From a5b4bd2874d9032b42db8cc4880058576c561b06 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 24 Sep 2013 10:35:14 +0100 Subject: KEYS: Use bool in make_key_ref() and is_key_possessed() Make make_key_ref() take a bool possession parameter and make is_key_possessed() return a bool. Signed-off-by: David Howells --- Documentation/security/keys.txt | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/security/keys.txt b/Documentation/security/keys.txt index 7b4145d00452..9ede67084f0b 100644 --- a/Documentation/security/keys.txt +++ b/Documentation/security/keys.txt @@ -865,15 +865,14 @@ encountered: calling processes has a searchable link to the key from one of its keyrings. There are three functions for dealing with these: - key_ref_t make_key_ref(const struct key *key, - unsigned long possession); + key_ref_t make_key_ref(const struct key *key, bool possession); struct key *key_ref_to_ptr(const key_ref_t key_ref); - unsigned long is_key_possessed(const key_ref_t key_ref); + bool is_key_possessed(const key_ref_t key_ref); The first function constructs a key reference from a key pointer and - possession information (which must be 0 or 1 and not any other value). + possession information (which must be true or false). The second function retrieves the key pointer from a reference and the third retrieves the possession flag. -- cgit v1.2.3 From ccc3e6d9c9aea07a0b60b2b0bfc5b05a704b66d5 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 24 Sep 2013 10:35:16 +0100 Subject: KEYS: Define a __key_get() wrapper to use rather than atomic_inc() Define a __key_get() wrapper to use rather than atomic_inc() on the key usage count as this makes it easier to hook in refcount error debugging. Signed-off-by: David Howells --- Documentation/security/keys.txt | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'Documentation') diff --git a/Documentation/security/keys.txt b/Documentation/security/keys.txt index 9ede67084f0b..a4c33f1a7c6d 100644 --- a/Documentation/security/keys.txt +++ b/Documentation/security/keys.txt @@ -960,14 +960,17 @@ payload contents" for more information. the argument will not be parsed. -(*) Extra references can be made to a key by calling the following function: +(*) Extra references can be made to a key by calling one of the following + functions: + struct key *__key_get(struct key *key); struct key *key_get(struct key *key); - These need to be disposed of by calling key_put() when they've been - finished with. The key pointer passed in will be returned. If the pointer - is NULL or CONFIG_KEYS is not set then the key will not be dereferenced and - no increment will take place. + Keys so references will need to be disposed of by calling key_put() when + they've been finished with. The key pointer passed in will be returned. + + In the case of key_get(), if the pointer is NULL or CONFIG_KEYS is not set + then the key will not be dereferenced and no increment will take place. (*) A key's serial number can be obtained by calling: -- cgit v1.2.3 From 3cb989501c2688cacbb7dc4b0d353faf838f53a1 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 24 Sep 2013 10:35:17 +0100 Subject: Add a generic associative array implementation. Add a generic associative array implementation that can be used as the container for keyrings, thereby massively increasing the capacity available whilst also speeding up searching in keyrings that contain a lot of keys. This may also be useful in FS-Cache for tracking cookies. Documentation is added into Documentation/associative_array.txt Some of the properties of the implementation are: (1) Objects are opaque pointers. The implementation does not care where they point (if anywhere) or what they point to (if anything). [!] NOTE: Pointers to objects _must_ be zero in the two least significant bits. (2) Objects do not need to contain linkage blocks for use by the array. This permits an object to be located in multiple arrays simultaneously. Rather, the array is made up of metadata blocks that point to objects. (3) Objects are labelled as being one of two types (the type is a bool value). This information is stored in the array, but has no consequence to the array itself or its algorithms. (4) Objects require index keys to locate them within the array. (5) Index keys must be unique. Inserting an object with the same key as one already in the array will replace the old object. (6) Index keys can be of any length and can be of different lengths. (7) Index keys should encode the length early on, before any variation due to length is seen. (8) Index keys can include a hash to scatter objects throughout the array. (9) The array can iterated over. The objects will not necessarily come out in key order. (10) The array can be iterated whilst it is being modified, provided the RCU readlock is being held by the iterator. Note, however, under these circumstances, some objects may be seen more than once. If this is a problem, the iterator should lock against modification. Objects will not be missed, however, unless deleted. (11) Objects in the array can be looked up by means of their index key. (12) Objects can be looked up whilst the array is being modified, provided the RCU readlock is being held by the thread doing the look up. The implementation uses a tree of 16-pointer nodes internally that are indexed on each level by nibbles from the index key. To improve memory efficiency, shortcuts can be emplaced to skip over what would otherwise be a series of single-occupancy nodes. Further, nodes pack leaf object pointers into spare space in the node rather than making an extra branch until as such time an object needs to be added to a full node. Signed-off-by: David Howells --- Documentation/assoc_array.txt | 574 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 574 insertions(+) create mode 100644 Documentation/assoc_array.txt (limited to 'Documentation') diff --git a/Documentation/assoc_array.txt b/Documentation/assoc_array.txt new file mode 100644 index 000000000000..f4faec0f66e4 --- /dev/null +++ b/Documentation/assoc_array.txt @@ -0,0 +1,574 @@ + ======================================== + GENERIC ASSOCIATIVE ARRAY IMPLEMENTATION + ======================================== + +Contents: + + - Overview. + + - The public API. + - Edit script. + - Operations table. + - Manipulation functions. + - Access functions. + - Index key form. + + - Internal workings. + - Basic internal tree layout. + - Shortcuts. + - Splitting and collapsing nodes. + - Non-recursive iteration. + - Simultaneous alteration and iteration. + + +======== +OVERVIEW +======== + +This associative array implementation is an object container with the following +properties: + + (1) Objects are opaque pointers. The implementation does not care where they + point (if anywhere) or what they point to (if anything). + + [!] NOTE: Pointers to objects _must_ be zero in the least significant bit. + + (2) Objects do not need to contain linkage blocks for use by the array. This + permits an object to be located in multiple arrays simultaneously. + Rather, the array is made up of metadata blocks that point to objects. + + (3) Objects require index keys to locate them within the array. + + (4) Index keys must be unique. Inserting an object with the same key as one + already in the array will replace the old object. + + (5) Index keys can be of any length and can be of different lengths. + + (6) Index keys should encode the length early on, before any variation due to + length is seen. + + (7) Index keys can include a hash to scatter objects throughout the array. + + (8) The array can iterated over. The objects will not necessarily come out in + key order. + + (9) The array can be iterated over whilst it is being modified, provided the + RCU readlock is being held by the iterator. Note, however, under these + circumstances, some objects may be seen more than once. If this is a + problem, the iterator should lock against modification. Objects will not + be missed, however, unless deleted. + +(10) Objects in the array can be looked up by means of their index key. + +(11) Objects can be looked up whilst the array is being modified, provided the + RCU readlock is being held by the thread doing the look up. + +The implementation uses a tree of 16-pointer nodes internally that are indexed +on each level by nibbles from the index key in the same manner as in a radix +tree. To improve memory efficiency, shortcuts can be emplaced to skip over +what would otherwise be a series of single-occupancy nodes. Further, nodes +pack leaf object pointers into spare space in the node rather than making an +extra branch until as such time an object needs to be added to a full node. + + +============== +THE PUBLIC API +============== + +The public API can be found in . The associative array is +rooted on the following structure: + + struct assoc_array { + ... + }; + +The code is selected by enabling CONFIG_ASSOCIATIVE_ARRAY. + + +EDIT SCRIPT +----------- + +The insertion and deletion functions produce an 'edit script' that can later be +applied to effect the changes without risking ENOMEM. This retains the +preallocated metadata blocks that will be installed in the internal tree and +keeps track of the metadata blocks that will be removed from the tree when the +script is applied. + +This is also used to keep track of dead blocks and dead objects after the +script has been applied so that they can be freed later. The freeing is done +after an RCU grace period has passed - thus allowing access functions to +proceed under the RCU read lock. + +The script appears as outside of the API as a pointer of the type: + + struct assoc_array_edit; + +There are two functions for dealing with the script: + + (1) Apply an edit script. + + void assoc_array_apply_edit(struct assoc_array_edit *edit); + + This will perform the edit functions, interpolating various write barriers + to permit accesses under the RCU read lock to continue. The edit script + will then be passed to call_rcu() to free it and any dead stuff it points + to. + + (2) Cancel an edit script. + + void assoc_array_cancel_edit(struct assoc_array_edit *edit); + + This frees the edit script and all preallocated memory immediately. If + this was for insertion, the new object is _not_ released by this function, + but must rather be released by the caller. + +These functions are guaranteed not to fail. + + +OPERATIONS TABLE +---------------- + +Various functions take a table of operations: + + struct assoc_array_ops { + ... + }; + +This points to a number of methods, all of which need to be provided: + + (1) Get a chunk of index key from caller data: + + unsigned long (*get_key_chunk)(const void *index_key, int level); + + This should return a chunk of caller-supplied index key starting at the + *bit* position given by the level argument. The level argument will be a + multiple of ASSOC_ARRAY_KEY_CHUNK_SIZE and the function should return + ASSOC_ARRAY_KEY_CHUNK_SIZE bits. No error is possible. + + + (2) Get a chunk of an object's index key. + + unsigned long (*get_object_key_chunk)(const void *object, int level); + + As the previous function, but gets its data from an object in the array + rather than from a caller-supplied index key. + + + (3) See if this is the object we're looking for. + + bool (*compare_object)(const void *object, const void *index_key); + + Compare the object against an index key and return true if it matches and + false if it doesn't. + + + (4) Diff the index keys of two objects. + + int (*diff_objects)(const void *a, const void *b); + + Return the bit position at which the index keys of two objects differ or + -1 if they are the same. + + + (5) Free an object. + + void (*free_object)(void *object); + + Free the specified object. Note that this may be called an RCU grace + period after assoc_array_apply_edit() was called, so synchronize_rcu() may + be necessary on module unloading. + + +MANIPULATION FUNCTIONS +---------------------- + +There are a number of functions for manipulating an associative array: + + (1) Initialise an associative array. + + void assoc_array_init(struct assoc_array *array); + + This initialises the base structure for an associative array. It can't + fail. + + + (2) Insert/replace an object in an associative array. + + struct assoc_array_edit * + assoc_array_insert(struct assoc_array *array, + const struct assoc_array_ops *ops, + const void *index_key, + void *object); + + This inserts the given object into the array. Note that the least + significant bit of the pointer must be zero as it's used to type-mark + pointers internally. + + If an object already exists for that key then it will be replaced with the + new object and the old one will be freed automatically. + + The index_key argument should hold index key information and is + passed to the methods in the ops table when they are called. + + This function makes no alteration to the array itself, but rather returns + an edit script that must be applied. -ENOMEM is returned in the case of + an out-of-memory error. + + The caller should lock exclusively against other modifiers of the array. + + + (3) Delete an object from an associative array. + + struct assoc_array_edit * + assoc_array_delete(struct assoc_array *array, + const struct assoc_array_ops *ops, + const void *index_key); + + This deletes an object that matches the specified data from the array. + + The index_key argument should hold index key information and is + passed to the methods in the ops table when they are called. + + This function makes no alteration to the array itself, but rather returns + an edit script that must be applied. -ENOMEM is returned in the case of + an out-of-memory error. NULL will be returned if the specified object is + not found within the array. + + The caller should lock exclusively against other modifiers of the array. + + + (4) Delete all objects from an associative array. + + struct assoc_array_edit * + assoc_array_clear(struct assoc_array *array, + const struct assoc_array_ops *ops); + + This deletes all the objects from an associative array and leaves it + completely empty. + + This function makes no alteration to the array itself, but rather returns + an edit script that must be applied. -ENOMEM is returned in the case of + an out-of-memory error. + + The caller should lock exclusively against other modifiers of the array. + + + (5) Destroy an associative array, deleting all objects. + + void assoc_array_destroy(struct assoc_array *array, + const struct assoc_array_ops *ops); + + This destroys the contents of the associative array and leaves it + completely empty. It is not permitted for another thread to be traversing + the array under the RCU read lock at the same time as this function is + destroying it as no RCU deferral is performed on memory release - + something that would require memory to be allocated. + + The caller should lock exclusively against other modifiers and accessors + of the array. + + + (6) Garbage collect an associative array. + + int assoc_array_gc(struct assoc_array *array, + const struct assoc_array_ops *ops, + bool (*iterator)(void *object, void *iterator_data), + void *iterator_data); + + This iterates over the objects in an associative array and passes each one + to iterator(). If iterator() returns true, the object is kept. If it + returns false, the object will be freed. If the iterator() function + returns true, it must perform any appropriate refcount incrementing on the + object before returning. + + The internal tree will be packed down if possible as part of the iteration + to reduce the number of nodes in it. + + The iterator_data is passed directly to iterator() and is otherwise + ignored by the function. + + The function will return 0 if successful and -ENOMEM if there wasn't + enough memory. + + It is possible for other threads to iterate over or search the array under + the RCU read lock whilst this function is in progress. The caller should + lock exclusively against other modifiers of the array. + + +ACCESS FUNCTIONS +---------------- + +There are two functions for accessing an associative array: + + (1) Iterate over all the objects in an associative array. + + int assoc_array_iterate(const struct assoc_array *array, + int (*iterator)(const void *object, + void *iterator_data), + void *iterator_data); + + This passes each object in the array to the iterator callback function. + iterator_data is private data for that function. + + This may be used on an array at the same time as the array is being + modified, provided the RCU read lock is held. Under such circumstances, + it is possible for the iteration function to see some objects twice. If + this is a problem, then modification should be locked against. The + iteration algorithm should not, however, miss any objects. + + The function will return 0 if no objects were in the array or else it will + return the result of the last iterator function called. Iteration stops + immediately if any call to the iteration function results in a non-zero + return. + + + (2) Find an object in an associative array. + + void *assoc_array_find(const struct assoc_array *array, + const struct assoc_array_ops *ops, + const void *index_key); + + This walks through the array's internal tree directly to the object + specified by the index key.. + + This may be used on an array at the same time as the array is being + modified, provided the RCU read lock is held. + + The function will return the object if found (and set *_type to the object + type) or will return NULL if the object was not found. + + +INDEX KEY FORM +-------------- + +The index key can be of any form, but since the algorithms aren't told how long +the key is, it is strongly recommended that the index key includes its length +very early on before any variation due to the length would have an effect on +comparisons. + +This will cause leaves with different length keys to scatter away from each +other - and those with the same length keys to cluster together. + +It is also recommended that the index key begin with a hash of the rest of the +key to maximise scattering throughout keyspace. + +The better the scattering, the wider and lower the internal tree will be. + +Poor scattering isn't too much of a problem as there are shortcuts and nodes +can contain mixtures of leaves and metadata pointers. + +The index key is read in chunks of machine word. Each chunk is subdivided into +one nibble (4 bits) per level, so on a 32-bit CPU this is good for 8 levels and +on a 64-bit CPU, 16 levels. Unless the scattering is really poor, it is +unlikely that more than one word of any particular index key will have to be +used. + + +================= +INTERNAL WORKINGS +================= + +The associative array data structure has an internal tree. This tree is +constructed of two types of metadata blocks: nodes and shortcuts. + +A node is an array of slots. Each slot can contain one of four things: + + (*) A NULL pointer, indicating that the slot is empty. + + (*) A pointer to an object (a leaf). + + (*) A pointer to a node at the next level. + + (*) A pointer to a shortcut. + + +BASIC INTERNAL TREE LAYOUT +-------------------------- + +Ignoring shortcuts for the moment, the nodes form a multilevel tree. The index +key space is strictly subdivided by the nodes in the tree and nodes occur on +fixed levels. For example: + + Level: 0 1 2 3 + =============== =============== =============== =============== + NODE D + NODE B NODE C +------>+---+ + +------>+---+ +------>+---+ | | 0 | + NODE A | | 0 | | | 0 | | +---+ + +---+ | +---+ | +---+ | : : + | 0 | | : : | : : | +---+ + +---+ | +---+ | +---+ | | f | + | 1 |---+ | 3 |---+ | 7 |---+ +---+ + +---+ +---+ +---+ + : : : : | 8 |---+ + +---+ +---+ +---+ | NODE E + | e |---+ | f | : : +------>+---+ + +---+ | +---+ +---+ | 0 | + | f | | | f | +---+ + +---+ | +---+ : : + | NODE F +---+ + +------>+---+ | f | + | 0 | NODE G +---+ + +---+ +------>+---+ + : : | | 0 | + +---+ | +---+ + | 6 |---+ : : + +---+ +---+ + : : | f | + +---+ +---+ + | f | + +---+ + +In the above example, there are 7 nodes (A-G), each with 16 slots (0-f). +Assuming no other meta data nodes in the tree, the key space is divided thusly: + + KEY PREFIX NODE + ========== ==== + 137* D + 138* E + 13[0-69-f]* C + 1[0-24-f]* B + e6* G + e[0-57-f]* F + [02-df]* A + +So, for instance, keys with the following example index keys will be found in +the appropriate nodes: + + INDEX KEY PREFIX NODE + =============== ======= ==== + 13694892892489 13 C + 13795289025897 137 D + 13889dde88793 138 E + 138bbb89003093 138 E + 1394879524789 12 C + 1458952489 1 B + 9431809de993ba - A + b4542910809cd - A + e5284310def98 e F + e68428974237 e6 G + e7fffcbd443 e F + f3842239082 - A + +To save memory, if a node can hold all the leaves in its portion of keyspace, +then the node will have all those leaves in it and will not have any metadata +pointers - even if some of those leaves would like to be in the same slot. + +A node can contain a heterogeneous mix of leaves and metadata pointers. +Metadata pointers must be in the slots that match their subdivisions of key +space. The leaves can be in any slot not occupied by a metadata pointer. It +is guaranteed that none of the leaves in a node will match a slot occupied by a +metadata pointer. If the metadata pointer is there, any leaf whose key matches +the metadata key prefix must be in the subtree that the metadata pointer points +to. + +In the above example list of index keys, node A will contain: + + SLOT CONTENT INDEX KEY (PREFIX) + ==== =============== ================== + 1 PTR TO NODE B 1* + any LEAF 9431809de993ba + any LEAF b4542910809cd + e PTR TO NODE F e* + any LEAF f3842239082 + +and node B: + + 3 PTR TO NODE C 13* + any LEAF 1458952489 + + +SHORTCUTS +--------- + +Shortcuts are metadata records that jump over a piece of keyspace. A shortcut +is a replacement for a series of single-occupancy nodes ascending through the +levels. Shortcuts exist to save memory and to speed up traversal. + +It is possible for the root of the tree to be a shortcut - say, for example, +the tree contains at least 17 nodes all with key prefix '1111'. The insertion +algorithm will insert a shortcut to skip over the '1111' keyspace in a single +bound and get to the fourth level where these actually become different. + + +SPLITTING AND COLLAPSING NODES +------------------------------ + +Each node has a maximum capacity of 16 leaves and metadata pointers. If the +insertion algorithm finds that it is trying to insert a 17th object into a +node, that node will be split such that at least two leaves that have a common +key segment at that level end up in a separate node rooted on that slot for +that common key segment. + +If the leaves in a full node and the leaf that is being inserted are +sufficiently similar, then a shortcut will be inserted into the tree. + +When the number of objects in the subtree rooted at a node falls to 16 or +fewer, then the subtree will be collapsed down to a single node - and this will +ripple towards the root if possible. + + +NON-RECURSIVE ITERATION +----------------------- + +Each node and shortcut contains a back pointer to its parent and the number of +slot in that parent that points to it. None-recursive iteration uses these to +proceed rootwards through the tree, going to the parent node, slot N + 1 to +make sure progress is made without the need for a stack. + +The backpointers, however, make simultaneous alteration and iteration tricky. + + +SIMULTANEOUS ALTERATION AND ITERATION +------------------------------------- + +There are a number of cases to consider: + + (1) Simple insert/replace. This involves simply replacing a NULL or old + matching leaf pointer with the pointer to the new leaf after a barrier. + The metadata blocks don't change otherwise. An old leaf won't be freed + until after the RCU grace period. + + (2) Simple delete. This involves just clearing an old matching leaf. The + metadata blocks don't change otherwise. The old leaf won't be freed until + after the RCU grace period. + + (3) Insertion replacing part of a subtree that we haven't yet entered. This + may involve replacement of part of that subtree - but that won't affect + the iteration as we won't have reached the pointer to it yet and the + ancestry blocks are not replaced (the layout of those does not change). + + (4) Insertion replacing nodes that we're actively processing. This isn't a + problem as we've passed the anchoring pointer and won't switch onto the + new layout until we follow the back pointers - at which point we've + already examined the leaves in the replaced node (we iterate over all the + leaves in a node before following any of its metadata pointers). + + We might, however, re-see some leaves that have been split out into a new + branch that's in a slot further along than we were at. + + (5) Insertion replacing nodes that we're processing a dependent branch of. + This won't affect us until we follow the back pointers. Similar to (4). + + (6) Deletion collapsing a branch under us. This doesn't affect us because the + back pointers will get us back to the parent of the new node before we + could see the new node. The entire collapsed subtree is thrown away + unchanged - and will still be rooted on the same slot, so we shouldn't + process it a second time as we'll go back to slot + 1. + +Note: + + (*) Under some circumstances, we need to simultaneously change the parent + pointer and the parent slot pointer on a node (say, for example, we + inserted another node before it and moved it up a level). We cannot do + this without locking against a read - so we have to replace that node too. + + However, when we're changing a shortcut into a node this isn't a problem + as shortcuts only have one slot and so the parent slot number isn't used + when traversing backwards over one. This means that it's okay to change + the slot number first - provided suitable barriers are used to make sure + the parent slot number is read after the back pointer. + +Obsolete blocks and leaves are freed up after an RCU grace period has passed, +so as long as anyone doing walking or iteration holds the RCU read lock, the +old superstructure should not go away on them. -- cgit v1.2.3 From d80e224dd52dfc448e820aefa5f86c441ab76e1a Mon Sep 17 00:00:00 2001 From: Andy Grover Date: Wed, 9 Oct 2013 11:05:56 -0700 Subject: target: Remove TF_CIT_TMPL macro Remove a lingering macro that just hid a dereference. Reviewed-by: Christoph Hellwig Signed-off-by: Andy Grover Signed-off-by: Nicholas Bellinger --- Documentation/target/tcm_mod_builder.py | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) (limited to 'Documentation') diff --git a/Documentation/target/tcm_mod_builder.py b/Documentation/target/tcm_mod_builder.py index 54d29c1320ed..230ce71f4d75 100755 --- a/Documentation/target/tcm_mod_builder.py +++ b/Documentation/target/tcm_mod_builder.py @@ -440,15 +440,15 @@ def tcm_mod_build_configfs(proto_ident, fabric_mod_dir_var, fabric_mod_name): buf += " /*\n" buf += " * Setup default attribute lists for various fabric->tf_cit_tmpl\n" buf += " */\n" - buf += " TF_CIT_TMPL(fabric)->tfc_wwn_cit.ct_attrs = " + fabric_mod_name + "_wwn_attrs;\n" - buf += " TF_CIT_TMPL(fabric)->tfc_tpg_base_cit.ct_attrs = NULL;\n" - buf += " TF_CIT_TMPL(fabric)->tfc_tpg_attrib_cit.ct_attrs = NULL;\n" - buf += " TF_CIT_TMPL(fabric)->tfc_tpg_param_cit.ct_attrs = NULL;\n" - buf += " TF_CIT_TMPL(fabric)->tfc_tpg_np_base_cit.ct_attrs = NULL;\n" - buf += " TF_CIT_TMPL(fabric)->tfc_tpg_nacl_base_cit.ct_attrs = NULL;\n" - buf += " TF_CIT_TMPL(fabric)->tfc_tpg_nacl_attrib_cit.ct_attrs = NULL;\n" - buf += " TF_CIT_TMPL(fabric)->tfc_tpg_nacl_auth_cit.ct_attrs = NULL;\n" - buf += " TF_CIT_TMPL(fabric)->tfc_tpg_nacl_param_cit.ct_attrs = NULL;\n" + buf += " fabric->tf_cit_tmpl.tfc_wwn_cit.ct_attrs = " + fabric_mod_name + "_wwn_attrs;\n" + buf += " fabric->tf_cit_tmpl.tfc_tpg_base_cit.ct_attrs = NULL;\n" + buf += " fabric->tf_cit_tmpl.tfc_tpg_attrib_cit.ct_attrs = NULL;\n" + buf += " fabric->tf_cit_tmpl.tfc_tpg_param_cit.ct_attrs = NULL;\n" + buf += " fabric->tf_cit_tmpl.tfc_tpg_np_base_cit.ct_attrs = NULL;\n" + buf += " fabric->tf_cit_tmpl.tfc_tpg_nacl_base_cit.ct_attrs = NULL;\n" + buf += " fabric->tf_cit_tmpl.tfc_tpg_nacl_attrib_cit.ct_attrs = NULL;\n" + buf += " fabric->tf_cit_tmpl.tfc_tpg_nacl_auth_cit.ct_attrs = NULL;\n" + buf += " fabric->tf_cit_tmpl.tfc_tpg_nacl_param_cit.ct_attrs = NULL;\n" buf += " /*\n" buf += " * Register the fabric for use within TCM\n" buf += " */\n" -- cgit v1.2.3 From 13098cf05a430464f50ffac73cfa2c467768410d Mon Sep 17 00:00:00 2001 From: Ludovic Desroches Date: Fri, 4 Oct 2013 10:46:51 +0200 Subject: dma: atmel-dma: correct typo in the device tree bindings documentation The value to set ASAP mode for FIFO configuration is 2 instead of 1. Signed-off-by: Ludovic Desroches Acked-by: Nicolas Ferre Signed-off-by: Vinod Koul --- Documentation/devicetree/bindings/dma/atmel-dma.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/dma/atmel-dma.txt b/Documentation/devicetree/bindings/dma/atmel-dma.txt index e1f343c7a34b..f69bcf5a6343 100644 --- a/Documentation/devicetree/bindings/dma/atmel-dma.txt +++ b/Documentation/devicetree/bindings/dma/atmel-dma.txt @@ -28,7 +28,7 @@ The three cells in order are: dependent: - bit 7-0: peripheral identifier for the hardware handshaking interface. The identifier can be different for tx and rx. - - bit 11-8: FIFO configuration. 0 for half FIFO, 1 for ALAP, 1 for ASAP. + - bit 11-8: FIFO configuration. 0 for half FIFO, 1 for ALAP, 2 for ASAP. Example: -- cgit v1.2.3 From 4c336e4b1556f4b722ba597bc6e3df786968a600 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Sun, 6 Oct 2013 12:43:13 -0600 Subject: tpm: Add support for the Nuvoton NPCT501 I2C TPM This chip is/was also branded as a Winbond WPCT301. Originally written by Dan Morav and posted to LKML: https://lkml.org/lkml/2011/9/7/206 The original posting was not merged, I have taken it as a starting point, forward ported, tested and revised the driver: - Rework interrupt handling to work properly with level triggered interrupts. The old version just locked up. - Synchronize various items with Peter Huewe's Infineon driver: * Add durations/timeouts sysfs calls * Remove I2C device auto-detection * Don't fiddle with chip->release * Call tpm_dev_vendor_release in the probe error path * Use MODULE_DEVICE_TABLE for the I2C ids * Provide OF compatible strings for DT support * Use SIMPLE_DEV_PM_OPS * Use module_i2c_driver - checkpatch cleanups - Testing on ARM Kirkwood with GPIO interrupts, with this device tree: tpm@57 { compatible = "nuvoton,npct501"; reg = <0x57>; interrupt-parent = <&gpio1>; interrupts = <6 IRQ_TYPE_LEVEL_LOW>; }; Signed-off-by: Dan Morav [jgg: revised and tested] Signed-off-by: Jason Gunthorpe [phuewe: minor whitespace changes, fixed module name in kconfig] Signed-off-by: Peter Huewe --- Documentation/devicetree/bindings/i2c/trivial-devices.txt | 2 ++ 1 file changed, 2 insertions(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt index ad6a73852f08..58454bdfa20e 100644 --- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt +++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt @@ -44,6 +44,7 @@ mc,rv3029c2 Real Time Clock Module with I2C-Bus national,lm75 I2C TEMP SENSOR national,lm80 Serial Interface ACPI-Compatible Microprocessor System Hardware Monitor national,lm92 ±0.33°C Accurate, 12-Bit + Sign Temperature Sensor and Thermal Window Comparator with Two-Wire Interface +nuvoton,npct501 i2c trusted platform module (TPM) nxp,pca9556 Octal SMBus and I2C registered interface nxp,pca9557 8-bit I2C-bus and SMBus I/O port with reset nxp,pcf8563 Real-time clock/calendar @@ -61,3 +62,4 @@ taos,tsl2550 Ambient Light Sensor with SMBUS/Two Wire Serial Interface ti,tsc2003 I2C Touch-Screen Controller ti,tmp102 Low Power Digital Temperature Sensor with SMBUS/Two Wire Serial Interface ti,tmp275 Digital Temperature Sensor +winbond,wpct301 i2c trusted platform module (TPM) -- cgit v1.2.3 From a2871c62e1865c45f87a9343de76f727fb7a0ffd Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Sun, 6 Oct 2013 12:43:36 -0600 Subject: tpm: Add support for Atmel I2C TPMs This is based on the work of Teddy Reed published on GitHub: https://github.com/theopolis/tpm-i2c-atmel.git 34894b988b67e0ae55088d6388e77b0dbf10c07d That driver was never merged, I have taken it as a starting port, forward ported, tested and revised the driver: - Make it broadly textually similar to the Infineon and Nuvoton I2C driver - Place everything in a format suitable for mainline inclusion - Use high level I2C functions i2c_master_send and i2c_master_recv for data xfer - Use the timeout system from the core code, by faking out a status register - Only I2C transfer the number of bytes in the reply, not a fixed message size. - checkpatch cleanups - Testing on ARM Kirkwood, with this device tree, using a AT97SC3204T-X1A180 tpm@29 { compatible = "atmel,at97sc3204t"; reg = <0x29>; }; Signed-off-by: Teddy Reed [jgg: revised and tested] Signed-off-by: Jason Gunthorpe [phuewe: minor whitespace changes] Signed-off-by: Peter Huewe --- Documentation/devicetree/bindings/i2c/trivial-devices.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt index 58454bdfa20e..f1fb26eed0e9 100644 --- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt +++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt @@ -15,6 +15,7 @@ adi,adt7461 +/-1C TDM Extended Temp Range I.C adt7461 +/-1C TDM Extended Temp Range I.C at,24c08 i2c serial eeprom (24cxx) atmel,24c02 i2c serial eeprom (24cxx) +atmel,at97sc3204t i2c trusted platform module (TPM) catalyst,24c32 i2c serial eeprom dallas,ds1307 64 x 8, Serial, I2C Real-Time Clock dallas,ds1338 I2C RTC with 56-Byte NV RAM -- cgit v1.2.3 From adf53a778a0a5a5dc9103509da4a9719046e5310 Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Fri, 7 Jun 2013 12:16:29 +0200 Subject: ima: new templates management mechanism MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The original 'ima' template is fixed length, containing the filedata hash and pathname. The filedata hash is limited to 20 bytes (md5/sha1). The pathname is a null terminated string, limited to 255 characters. To overcome these limitations and to add additional file metadata, it is necessary to extend the current version of IMA by defining additional templates. The main reason to introduce this feature is that, each time a new template is defined, the functions that generate and display the measurement list would include the code for handling a new format and, thus, would significantly grow over time. This patch set solves this problem by separating the template management from the remaining IMA code. The core of this solution is the definition of two new data structures: a template descriptor, to determine which information should be included in the measurement list, and a template field, to generate and display data of a given type. To define a new template field, developers define the field identifier and implement two functions, init() and show(), respectively to generate and display measurement entries. Initially, this patch set defines the following template fields (support for additional data types will be added later):  - 'd': the digest of the event (i.e. the digest of a measured file),         calculated with the SHA1 or MD5 hash algorithm;  - 'n': the name of the event (i.e. the file name), with size up to         255 bytes;  - 'd-ng': the digest of the event, calculated with an arbitrary hash            algorithm (field format: [:]digest, where the digest            prefix is shown only if the hash algorithm is not SHA1 or MD5);  - 'n-ng': the name of the event, without size limitations. Defining a new template descriptor requires specifying the template format, a string of field identifiers separated by the '|' character. This patch set defines the following template descriptors:  - "ima": its format is 'd|n';  - "ima-ng" (default): its format is 'd-ng|n-ng' Further details about the new template architecture can be found in Documentation/security/IMA-templates.txt. Changelog: - don't defer calling ima_init_template() - Mimi - don't define ima_lookup_template_desc() until used - Mimi - squashed with documentation patch - Mimi Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar --- Documentation/security/00-INDEX | 2 + Documentation/security/IMA-templates.txt | 87 ++++++++++++++++++++++++++++++++ 2 files changed, 89 insertions(+) create mode 100644 Documentation/security/IMA-templates.txt (limited to 'Documentation') diff --git a/Documentation/security/00-INDEX b/Documentation/security/00-INDEX index 414235c1fcfc..45c82fd3e9d3 100644 --- a/Documentation/security/00-INDEX +++ b/Documentation/security/00-INDEX @@ -22,3 +22,5 @@ keys.txt - description of the kernel key retention service. tomoyo.txt - documentation on the TOMOYO Linux Security Module. +IMA-templates.txt + - documentation on the template management mechanism for IMA. diff --git a/Documentation/security/IMA-templates.txt b/Documentation/security/IMA-templates.txt new file mode 100644 index 000000000000..a777e5f1df5b --- /dev/null +++ b/Documentation/security/IMA-templates.txt @@ -0,0 +1,87 @@ + IMA Template Management Mechanism + + +==== INTRODUCTION ==== + +The original 'ima' template is fixed length, containing the filedata hash +and pathname. The filedata hash is limited to 20 bytes (md5/sha1). +The pathname is a null terminated string, limited to 255 characters. +To overcome these limitations and to add additional file metadata, it is +necessary to extend the current version of IMA by defining additional +templates. For example, information that could be possibly reported are +the inode UID/GID or the LSM labels either of the inode and of the process +that is accessing it. + +However, the main problem to introduce this feature is that, each time +a new template is defined, the functions that generate and display +the measurements list would include the code for handling a new format +and, thus, would significantly grow over the time. + +The proposed solution solves this problem by separating the template +management from the remaining IMA code. The core of this solution is the +definition of two new data structures: a template descriptor, to determine +which information should be included in the measurement list; a template +field, to generate and display data of a given type. + +Managing templates with these structures is very simple. To support +a new data type, developers define the field identifier and implement +two functions, init() and show(), respectively to generate and display +measurement entries. Defining a new template descriptor requires +specifying the template format, a string of field identifiers separated +by the '|' character. While in the current implementation it is possible +to define new template descriptors only by adding their definition in the +template specific code (ima_template.c), in a future version it will be +possible to register a new template on a running kernel by supplying to IMA +the desired format string. In this version, IMA initializes at boot time +all defined template descriptors by translating the format into an array +of template fields structures taken from the set of the supported ones. + +After the initialization step, IMA will call ima_alloc_init_template() +(new function defined within the patches for the new template management +mechanism) to generate a new measurement entry by using the template +descriptor chosen through the kernel configuration or through the newly +introduced 'ima_template=' kernel command line parameter. It is during this +phase that the advantages of the new architecture are clearly shown: +the latter function will not contain specific code to handle a given template +but, instead, it simply calls the init() method of the template fields +associated to the chosen template descriptor and store the result (pointer +to allocated data and data length) in the measurement entry structure. + +The same mechanism is employed to display measurements entries. +The functions ima[_ascii]_measurements_show() retrieve, for each entry, +the template descriptor used to produce that entry and call the show() +method for each item of the array of template fields structures. + + + +==== SUPPORTED TEMPLATE FIELDS AND DESCRIPTORS ==== + +In the following, there is the list of supported template fields +('': description), that can be used to define new template +descriptors by adding their identifier to the format string +(support for more data types will be added later): + + - 'd': the digest of the event (i.e. the digest of a measured file), + calculated with the SHA1 or MD5 hash algorithm; + - 'n': the name of the event (i.e. the file name), with size up to 255 bytes; + - 'd-ng': the digest of the event, calculated with an arbitrary hash + algorithm (field format: [:]digest, where the digest + prefix is shown only if the hash algorithm is not SHA1 or MD5); + - 'n-ng': the name of the event, without size limitations. + + +Below, there is the list of defined template descriptors: + - "ima": its format is 'd|n'; + - "ima-ng" (default): its format is 'd-ng|n-ng'. + + + +==== USE ==== + +To specify the template descriptor to be used to generate measurement entries, +currently the following methods are supported: + + - select a template descriptor among those supported in the kernel + configuration ('ima-ng' is the default choice); + - specify a template descriptor name from the kernel command line through + the 'ima_template=' parameter. -- cgit v1.2.3 From 9b9d4ce592d283fc4c01da746c02a840c499bb7e Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Fri, 7 Jun 2013 12:16:35 +0200 Subject: ima: define kernel parameter 'ima_template=' to change configured default This patch allows users to specify from the kernel command line the template descriptor, among those defined, that will be used to generate and display measurement entries. If an user specifies a wrong template, IMA reverts to the template descriptor set in the kernel configuration. Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar --- Documentation/kernel-parameters.txt | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 1a036cd972fb..2b78cb55ac34 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1190,6 +1190,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. programs exec'd, files mmap'd for exec, and all files opened for read by uid=0. + ima_template= [IMA] + Select one of defined IMA measurements template formats. + Formats: { "ima" | "ima-ng" } + Default: "ima-ng" + init= [KNL] Format: Run specified binary instead of /sbin/init as init -- cgit v1.2.3 From e7a2ad7eb6f48ad80c70a22dd8167fb34b409466 Mon Sep 17 00:00:00 2001 From: Mimi Zohar Date: Fri, 7 Jun 2013 12:16:37 +0200 Subject: ima: enable support for larger default filedata hash algorithms The IMA measurement list contains two hashes - a template data hash and a filedata hash. The template data hash is committed to the TPM, which is limited, by the TPM v1.2 specification, to 20 bytes. The filedata hash is defined as 20 bytes as well. Now that support for variable length measurement list templates was added, the filedata hash is not limited to 20 bytes. This patch adds Kconfig support for defining larger default filedata hash algorithms and replacing the builtin default with one specified on the kernel command line. contains a list of hash algorithms. The Kconfig default hash algorithm is a subset of this list, but any hash algorithm included in the list can be specified at boot, using the 'ima_hash=' kernel command line option. Changelog v2: - update Kconfig Changelog: - support hashes that are configured - use generic HASH_ALGO_ definitions - add Kconfig support - hash_setup must be called only once (Dmitry) - removed trailing whitespaces (Roberto Sassu) Signed-off-by: Mimi Zohar Signed-off-by: Roberto Sassu --- Documentation/kernel-parameters.txt | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 2b78cb55ac34..1e8761c89a2c 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1181,9 +1181,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. owned by uid=0. ima_hash= [IMA] - Format: { "sha1" | "md5" } + Format: { md5 | sha1 | rmd160 | sha256 | sha384 + | sha512 | ... } default: "sha1" + The list of supported hash algorithms is defined + in crypto/hash_info.h. + ima_tcb [IMA] Load a policy which meets the needs of the Trusted Computing Base. This means IMA will measure all -- cgit v1.2.3 From 2883229309a13760296abc91ac5f64f3dffc4801 Mon Sep 17 00:00:00 2001 From: Stanimir Varbanov Date: Tue, 15 Oct 2013 17:11:17 +0300 Subject: ARM: DT: msm: Add Qualcomm's PRNG driver binding document This adds Qualcomm PRNG driver device tree binding documentation to use as an example in dts trees. Signed-off-by: Stanimir Varbanov Reviewed-by: Stephen Boyd Signed-off-by: Herbert Xu --- Documentation/devicetree/bindings/rng/qcom,prng.txt | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) create mode 100644 Documentation/devicetree/bindings/rng/qcom,prng.txt (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/rng/qcom,prng.txt b/Documentation/devicetree/bindings/rng/qcom,prng.txt new file mode 100644 index 000000000000..8e5853c2879b --- /dev/null +++ b/Documentation/devicetree/bindings/rng/qcom,prng.txt @@ -0,0 +1,17 @@ +Qualcomm MSM pseudo random number generator. + +Required properties: + +- compatible : should be "qcom,prng" +- reg : specifies base physical address and size of the registers map +- clocks : phandle to clock-controller plus clock-specifier pair +- clock-names : "core" clocks all registers, FIFO and circuits in PRNG IP block + +Example: + + rng@f9bff000 { + compatible = "qcom,prng"; + reg = <0xf9bff000 0x200>; + clocks = <&clock GCC_PRNG_AHB_CLK>; + clock-names = "core"; + }; -- cgit v1.2.3 From ea309944e226d655d7d4adca9623c575ba786bbe Mon Sep 17 00:00:00 2001 From: Ulf Hansson Date: Fri, 8 Nov 2013 06:13:51 +0100 Subject: PM / Runtime: Update documentation around probe|remove|suspend PM core and driver core has changed some behavior regarding use of runtime PM. Update the documentation accordingly. Signed-off-by: Ulf Hansson Signed-off-by: Rafael J. Wysocki --- Documentation/power/runtime_pm.txt | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) (limited to 'Documentation') diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index 0f54333b0ff2..b6ce00b2be9a 100644 --- a/Documentation/power/runtime_pm.txt +++ b/Documentation/power/runtime_pm.txt @@ -547,13 +547,11 @@ helper functions described in Section 4. In that case, pm_runtime_resume() should be used. Of course, for this purpose the device's runtime PM has to be enabled earlier by calling pm_runtime_enable(). -If the device bus type's or driver's ->probe() callback runs -pm_runtime_suspend() or pm_runtime_idle() or their asynchronous counterparts, -they will fail returning -EAGAIN, because the device's usage counter is -incremented by the driver core before executing ->probe(). Still, it may be -desirable to suspend the device as soon as ->probe() has finished, so the driver -core uses pm_runtime_put_sync() to invoke the subsystem-level idle callback for -the device at that time. +It may be desirable to suspend the device once ->probe() has finished. +Therefore the driver core uses the asyncronous pm_request_idle() to submit a +request to execute the subsystem-level idle callback for the device at that +time. A driver that makes use of the runtime autosuspend feature, may want to +update the last busy mark before returning from ->probe(). Moreover, the driver core prevents runtime PM callbacks from racing with the bus notifier callback in __device_release_driver(), which is necessary, because the @@ -656,7 +654,7 @@ out the following operations: __pm_runtime_disable() with 'false' as the second argument for every device right before executing the subsystem-level .suspend_late() callback for it. - * During system resume it calls pm_runtime_enable() and pm_runtime_put_sync() + * During system resume it calls pm_runtime_enable() and pm_runtime_put() for every device right after executing the subsystem-level .resume_early() callback and right after executing the subsystem-level .resume() callback for it, respectively. -- cgit v1.2.3 From c3d68d8dd4f8d44579e2f0d121990f288c4a0e9a Mon Sep 17 00:00:00 2001 From: Hongbo Zhang Date: Thu, 26 Sep 2013 17:33:41 +0800 Subject: DMA: Freescale: revise device tree binding document This patch updates the discription of each type of DMA controller and its channels, it is preparation for adding another new DMA controller binding, it also fixes some defects of indent for text alignment at the same time. Signed-off-by: Hongbo Zhang Acked-by: Mark Rutland Signed-off-by: Vinod Koul --- .../devicetree/bindings/powerpc/fsl/dma.txt | 68 ++++++++++------------ 1 file changed, 31 insertions(+), 37 deletions(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/powerpc/fsl/dma.txt b/Documentation/devicetree/bindings/powerpc/fsl/dma.txt index 2a4b4bce6110..05841689c4a3 100644 --- a/Documentation/devicetree/bindings/powerpc/fsl/dma.txt +++ b/Documentation/devicetree/bindings/powerpc/fsl/dma.txt @@ -1,33 +1,30 @@ -* Freescale 83xx DMA Controller +* Freescale DMA Controllers -Freescale PowerPC 83xx have on chip general purpose DMA controllers. +** Freescale Elo DMA Controller + This is a little-endian 4-channel DMA controller, used in Freescale mpc83xx + series chips such as mpc8315, mpc8349, mpc8379 etc. Required properties: -- compatible : compatible list, contains 2 entries, first is - "fsl,CHIP-dma", where CHIP is the processor - (mpc8349, mpc8360, etc.) and the second is - "fsl,elo-dma" -- reg : -- ranges : Should be defined as specified in 1) to describe the - DMA controller channels. +- compatible : must include "fsl,elo-dma" +- reg : DMA General Status Register, i.e. DGSR which contains + status for all the 4 DMA channels +- ranges : describes the mapping between the address space of the + DMA channels and the address space of the DMA controller - cell-index : controller index. 0 for controller @ 0x8100 -- interrupts : +- interrupts : interrupt specifier for DMA IRQ - interrupt-parent : optional, if needed for interrupt mapping - - DMA channel nodes: - - compatible : compatible list, contains 2 entries, first is - "fsl,CHIP-dma-channel", where CHIP is the processor - (mpc8349, mpc8350, etc.) and the second is - "fsl,elo-dma-channel". However, see note below. - - reg : - - cell-index : dma channel index starts at 0. + - compatible : must include "fsl,elo-dma-channel" + However, see note below. + - reg : DMA channel specific registers + - cell-index : DMA channel index starts at 0. Optional properties: - - interrupts : - (on 83xx this is expected to be identical to - the interrupts property of the parent node) + - interrupts : interrupt specifier for DMA channel IRQ + (on 83xx this is expected to be identical to + the interrupts property of the parent node) - interrupt-parent : optional, if needed for interrupt mapping Example: @@ -70,30 +67,27 @@ Example: }; }; -* Freescale 85xx/86xx DMA Controller - -Freescale PowerPC 85xx/86xx have on chip general purpose DMA controllers. +** Freescale EloPlus DMA Controller + This is a 4-channel DMA controller with extended addresses and chaining, + mainly used in Freescale mpc85xx/86xx, Pxxx and BSC series chips, such as + mpc8540, mpc8641 p4080, bsc9131 etc. Required properties: -- compatible : compatible list, contains 2 entries, first is - "fsl,CHIP-dma", where CHIP is the processor - (mpc8540, mpc8540, etc.) and the second is - "fsl,eloplus-dma" -- reg : +- compatible : must include "fsl,eloplus-dma" +- reg : DMA General Status Register, i.e. DGSR which contains + status for all the 4 DMA channels - cell-index : controller index. 0 for controller @ 0x21000, 1 for controller @ 0xc000 -- ranges : Should be defined as specified in 1) to describe the - DMA controller channels. +- ranges : describes the mapping between the address space of the + DMA channels and the address space of the DMA controller - DMA channel nodes: - - compatible : compatible list, contains 2 entries, first is - "fsl,CHIP-dma-channel", where CHIP is the processor - (mpc8540, mpc8560, etc.) and the second is - "fsl,eloplus-dma-channel". However, see note below. - - cell-index : dma channel index starts at 0. - - reg : - - interrupts : + - compatible : must include "fsl,eloplus-dma-channel" + However, see note below. + - cell-index : DMA channel index starts at 0. + - reg : DMA channel specific registers + - interrupts : interrupt specifier for DMA channel IRQ - interrupt-parent : optional, if needed for interrupt mapping Example: -- cgit v1.2.3 From 03aa254f1e3c3d902cd68763f8abc2387e82b4da Mon Sep 17 00:00:00 2001 From: Hongbo Zhang Date: Thu, 26 Sep 2013 17:33:42 +0800 Subject: DMA: Freescale: Add new 8-channel DMA engine device tree nodes Freescale QorIQ T4 and B4 introduce new 8-channel DMA engines, this patch adds the device tree nodes for them. Signed-off-by: Hongbo Zhang Acked-by: Mark Rutland Signed-off-by: Vinod Koul --- .../devicetree/bindings/powerpc/fsl/dma.txt | 70 ++++++++++++++++++++++ 1 file changed, 70 insertions(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/powerpc/fsl/dma.txt b/Documentation/devicetree/bindings/powerpc/fsl/dma.txt index 05841689c4a3..7fc1b010fa75 100644 --- a/Documentation/devicetree/bindings/powerpc/fsl/dma.txt +++ b/Documentation/devicetree/bindings/powerpc/fsl/dma.txt @@ -128,6 +128,76 @@ Example: }; }; +** Freescale Elo3 DMA Controller + DMA controller which has same function as EloPlus except that Elo3 has 8 + channels while EloPlus has only 4, it is used in Freescale Txxx and Bxxx + series chips, such as t1040, t4240, b4860. + +Required properties: + +- compatible : must include "fsl,elo3-dma" +- reg : contains two entries for DMA General Status Registers, + i.e. DGSR0 which includes status for channel 1~4, and + DGSR1 for channel 5~8 +- ranges : describes the mapping between the address space of the + DMA channels and the address space of the DMA controller + +- DMA channel nodes: + - compatible : must include "fsl,eloplus-dma-channel" + - reg : DMA channel specific registers + - interrupts : interrupt specifier for DMA channel IRQ + - interrupt-parent : optional, if needed for interrupt mapping + +Example: +dma@100300 { + #address-cells = <1>; + #size-cells = <1>; + compatible = "fsl,elo3-dma"; + reg = <0x100300 0x4>, + <0x100600 0x4>; + ranges = <0x0 0x100100 0x500>; + dma-channel@0 { + compatible = "fsl,eloplus-dma-channel"; + reg = <0x0 0x80>; + interrupts = <28 2 0 0>; + }; + dma-channel@80 { + compatible = "fsl,eloplus-dma-channel"; + reg = <0x80 0x80>; + interrupts = <29 2 0 0>; + }; + dma-channel@100 { + compatible = "fsl,eloplus-dma-channel"; + reg = <0x100 0x80>; + interrupts = <30 2 0 0>; + }; + dma-channel@180 { + compatible = "fsl,eloplus-dma-channel"; + reg = <0x180 0x80>; + interrupts = <31 2 0 0>; + }; + dma-channel@300 { + compatible = "fsl,eloplus-dma-channel"; + reg = <0x300 0x80>; + interrupts = <76 2 0 0>; + }; + dma-channel@380 { + compatible = "fsl,eloplus-dma-channel"; + reg = <0x380 0x80>; + interrupts = <77 2 0 0>; + }; + dma-channel@400 { + compatible = "fsl,eloplus-dma-channel"; + reg = <0x400 0x80>; + interrupts = <78 2 0 0>; + }; + dma-channel@480 { + compatible = "fsl,eloplus-dma-channel"; + reg = <0x480 0x80>; + interrupts = <79 2 0 0>; + }; +}; + Note on DMA channel compatible properties: The compatible property must say "fsl,elo-dma-channel" or "fsl,eloplus-dma-channel" to be used by the Elo DMA driver (fsldma). Any DMA channel used by fsldma cannot be used by another -- cgit v1.2.3 From 7b61017822cdff9c18ae70005cf52d84e8dafe5d Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 6 Nov 2013 16:29:57 -0800 Subject: Revert "dmatest: append verify result to results" This reverts commit d86b2f298e6de124984f5d5817ed1e6e759b3ada. The kernel log buffer is sufficient for collecting test results. The current logging OOMs the machine on long running tests, and usually only the first error is relevant. It is better to stop on error and parse the kernel output. If output volume becomes an issue we can always investigate using trace messages. Cc: Andy Shevchenko Acked-by: Andy Shevchenko Signed-off-by: Dan Williams --- Documentation/dmatest.txt | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/dmatest.txt b/Documentation/dmatest.txt index a2b5663eae26..8b7a5c879df9 100644 --- a/Documentation/dmatest.txt +++ b/Documentation/dmatest.txt @@ -76,7 +76,5 @@ The message format is unified across the different types of errors. A number in the parens represents additional information, e.g. error code, error counter, or status. -Comparison between buffers is stored to the dedicated structure. - -Note that the verify result is now accessible only via file 'results' in the -debugfs. +Note that the buffer comparison is done in the old way, i.e. data is not +collected and just printed out. -- cgit v1.2.3 From 872f05c6e9a37e9358fd58eb54deee7337863496 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 6 Nov 2013 16:29:58 -0800 Subject: dmatest: replace stored results mechanism, with uniform messages For long running tests the tracking results in a memory leak for the "ok" results, and for the failures the kernel log should be sufficient. Provide a uniform format for error messages so they can be easily parsed and remove the debugfs file. Cc: Andy Shevchenko Signed-off-by: Dan Williams --- Documentation/dmatest.txt | 27 +++++++++++++-------------- 1 file changed, 13 insertions(+), 14 deletions(-) (limited to 'Documentation') diff --git a/Documentation/dmatest.txt b/Documentation/dmatest.txt index 8b7a5c879df9..45b8c95f1a21 100644 --- a/Documentation/dmatest.txt +++ b/Documentation/dmatest.txt @@ -16,9 +16,8 @@ be built as module or inside kernel. Let's consider those cases. Part 2 - When dmatest is built as a module... After mounting debugfs and loading the module, the /sys/kernel/debug/dmatest -folder with nodes will be created. There are two important files located. First -is the 'run' node that controls run and stop phases of the test, and the second -one, 'results', is used to get the test case results. +folder with a file named 'run' nodes will be created. 'run' controls run and +stop phases of the test. Note that in this case test will not run on load automatically. @@ -32,8 +31,9 @@ Hint: available channel list could be extracted by running the following command: % ls -1 /sys/class/dma/ -After a while you will start to get messages about current status or error like -in the original code. +Once started a message like "dmatest: Started 1 threads using dma0chan0" is +emitted. After that only test failure messages are reported until the test +stops. Note that running a new test will not stop any in progress test. @@ -62,19 +62,18 @@ case. You always could check them at run-time by running Part 4 - Gathering the test results -The module provides a storage for the test results in the memory. The gathered -data could be used after test is done. +Test results are printed to the kernel log buffer with the format: -The special file 'results' in the debugfs represents gathered data of the in -progress test. The messages collected are printed to the kernel log as well. +"dmatest: result : : '' with src_off= dst_off= len= ()" Example of output: - % cat /sys/kernel/debug/dmatest/results - dma0chan0-copy0: #1: No errors with src_off=0x7bf dst_off=0x8ad len=0x3fea (0) + % dmesg | tail -n 1 + dmatest: result dma0chan0-copy0: #1: No errors with src_off=0x7bf dst_off=0x8ad len=0x3fea (0) The message format is unified across the different types of errors. A number in the parens represents additional information, e.g. error code, error counter, -or status. +or status. A test thread also emits a summary line at completion listing the +number of tests executed, number that failed, and a result code. -Note that the buffer comparison is done in the old way, i.e. data is not -collected and just printed out. +The details of a data miscompare error are also emitted, but do not follow the +above format. -- cgit v1.2.3 From a310d037b8d06755c62bb4878c00d19490af5550 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 6 Nov 2013 16:30:01 -0800 Subject: dmatest: restore ability to start test at module load and init 1/ move 'run' control to a module parameter so we can do: modprobe dmatest run=1. With this moved the rest of the debugfs boilerplate can go. 2/ Fix parameter initialization. Previously the test was being started without taking the parameters into account in the built-in case. Also killed off the '__' version of some routines. The new rule is just hold the lock when calling a *threaded_test() routine. Acked-by: Linus Walleij Cc: Andy Shevchenko Acked-by: Andy Shevchenko Signed-off-by: Dan Williams --- Documentation/dmatest.txt | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) (limited to 'Documentation') diff --git a/Documentation/dmatest.txt b/Documentation/dmatest.txt index 45b8c95f1a21..e6e16a7f3706 100644 --- a/Documentation/dmatest.txt +++ b/Documentation/dmatest.txt @@ -15,17 +15,19 @@ be built as module or inside kernel. Let's consider those cases. Part 2 - When dmatest is built as a module... -After mounting debugfs and loading the module, the /sys/kernel/debug/dmatest -folder with a file named 'run' nodes will be created. 'run' controls run and -stop phases of the test. - -Note that in this case test will not run on load automatically. - Example of usage: + % modprobe dmatest channel=dma0chan0 timeout=2000 iterations=1 run=1 + +...or: + % modprobe dmatest % echo dma0chan0 > /sys/module/dmatest/parameters/channel % echo 2000 > /sys/module/dmatest/parameters/timeout % echo 1 > /sys/module/dmatest/parameters/iterations - % echo 1 > /sys/kernel/debug/dmatest/run + % echo 1 > /sys/module/dmatest/parameters/run + +...or on the kernel command line: + + dmatest.channel=dma0chan0 dmatest.timeout=2000 dmatest.iterations=1 dmatest.run=1 Hint: available channel list could be extracted by running the following command: @@ -42,7 +44,7 @@ The following command should return actual state of the test. To wait for test done the user may perform a busy loop that checks the state. - % while [ $(cat /sys/kernel/debug/dmatest/run) = "Y" ] + % while [ $(cat /sys/module/dmatest/parameters/run) = "Y" ] > do > echo -n "." > sleep 1 -- cgit v1.2.3 From 86727443a04fdb25397041188efd2527f2b7237b Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 6 Nov 2013 16:30:07 -0800 Subject: dmatest: add basic performance metrics Add iops and throughput to the summary output. Acked-by: Andy Shevchenko Signed-off-by: Dan Williams --- Documentation/dmatest.txt | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'Documentation') diff --git a/Documentation/dmatest.txt b/Documentation/dmatest.txt index e6e16a7f3706..0beb4b68d81f 100644 --- a/Documentation/dmatest.txt +++ b/Documentation/dmatest.txt @@ -77,5 +77,9 @@ the parens represents additional information, e.g. error code, error counter, or status. A test thread also emits a summary line at completion listing the number of tests executed, number that failed, and a result code. +Example: + % dmesg | tail -n 1 + dmatest: dma3chan0-copy0: summary 400000 tests, 0 failures iops: 61524 KB/s 246098 (0) + The details of a data miscompare error are also emitted, but do not follow the above format. -- cgit v1.2.3 From 2d88ce76eb98c4ac4411dcb299cf61ca8999d2b9 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 6 Nov 2013 16:30:09 -0800 Subject: dmatest: add a 'wait' parameter Allows for scripting test runs by module load / unload. Prevent module load from returning until 'iterations' (finite) tests have completed, or cause reads of the 'wait' parameter in sysfs to pause until the tests are done. Also killed the local waitqueue since we can just let the thread exit naturally as long as we hold a reference. Cc: Nicolas Ferre Signed-off-by: Dan Williams --- Documentation/dmatest.txt | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) (limited to 'Documentation') diff --git a/Documentation/dmatest.txt b/Documentation/dmatest.txt index 0beb4b68d81f..dd77a81bdb80 100644 --- a/Documentation/dmatest.txt +++ b/Documentation/dmatest.txt @@ -39,17 +39,24 @@ stops. Note that running a new test will not stop any in progress test. -The following command should return actual state of the test. - % cat /sys/kernel/debug/dmatest/run +The following command returns the state of the test. + % cat /sys/module/dmatest/parameters/run -To wait for test done the user may perform a busy loop that checks the state. +To wait for test completion userpace can poll 'run' until it is false, or use +the wait parameter. Specifying 'wait=1' when loading the module causes module +initialization to pause until a test run has completed, while reading +/sys/module/dmatest/parameters/wait waits for any running test to complete +before returning. For example, the following scripts wait for 42 tests +to complete before exiting. Note that if 'iterations' is set to 'infinite' then +waiting is disabled. - % while [ $(cat /sys/module/dmatest/parameters/run) = "Y" ] - > do - > echo -n "." - > sleep 1 - > done - > echo +Example: + % modprobe dmatest run=1 iterations=42 wait=1 + % modprobe -r dmatest +...or: + % modprobe dmatest run=1 iterations=42 + % cat /sys/module/dmatest/parameters/wait + % modprobe -r dmatest Part 3 - When built-in in the kernel... @@ -79,7 +86,7 @@ number of tests executed, number that failed, and a result code. Example: % dmesg | tail -n 1 - dmatest: dma3chan0-copy0: summary 400000 tests, 0 failures iops: 61524 KB/s 246098 (0) + dmatest: dma0chan0-copy0: summary 1 test, 0 failures 1000 iops 100000 KB/s (0) The details of a data miscompare error are also emitted, but do not follow the above format. -- cgit v1.2.3 From 4c624840ebe2d84b72e4b2ab3e7390dddf74d0a5 Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Thu, 14 Nov 2013 15:25:07 -0800 Subject: i2c: omap: Fix missing device tree flags for omap2 As we claim to support device tree for mach-omap2, we should have the necessary flags in the driver to make it usable. Cc: linux-i2c@vger.kernel.org Acked-by: Wolfram Sang Signed-off-by: Tony Lindgren --- Documentation/devicetree/bindings/i2c/i2c-omap.txt | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/i2c/i2c-omap.txt b/Documentation/devicetree/bindings/i2c/i2c-omap.txt index 56564aa4b444..7e49839d4124 100644 --- a/Documentation/devicetree/bindings/i2c/i2c-omap.txt +++ b/Documentation/devicetree/bindings/i2c/i2c-omap.txt @@ -1,7 +1,8 @@ I2C for OMAP platforms Required properties : -- compatible : Must be "ti,omap3-i2c" or "ti,omap4-i2c" +- compatible : Must be "ti,omap2420-i2c", "ti,omap2430-i2c", "ti,omap3-i2c" + or "ti,omap4-i2c" - ti,hwmods : Must be "i2c", n being the instance number (1-based) - #address-cells = <1>; - #size-cells = <0>; -- cgit v1.2.3 From c98d6c65e6e6bd24a12174fff6ca4990d346de5d Mon Sep 17 00:00:00 2001 From: Arnaud Ebalard Date: Sat, 9 Nov 2013 18:39:14 +0100 Subject: hwmon: (lm75) Add support for GMT G751 chip This was tested on a NETGEAR ReadyNAS 2120 device (Marvell Armada XP based board, via DT). Signed-off-by: Arnaud Ebalard Signed-off-by: Guenter Roeck --- Documentation/devicetree/bindings/i2c/trivial-devices.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt index ad6a73852f08..c98e5a2934d8 100644 --- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt +++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt @@ -35,6 +35,7 @@ fsl,mc13892 MC13892: Power Management Integrated Circuit (PMIC) for i.MX35/51 fsl,mma8450 MMA8450Q: Xtrinsic Low-power, 3-axis Xtrinsic Accelerometer fsl,mpr121 MPR121: Proximity Capacitive Touch Sensor Controller fsl,sgtl5000 SGTL5000: Ultra Low-Power Audio Codec +gmt,g751 G751: Digital Temperature Sensor and Thermal Watchdog with Two-Wire Interface infineon,slb9635tt Infineon SLB9635 (Soft-) I2C TPM (old protocol, max 100khz) infineon,slb9645tt Infineon SLB9645 I2C TPM (new protocol, max 400khz) maxim,ds1050 5 Bit Programmable, Pulse-Width Modulator -- cgit v1.2.3 From 906c176e541f89ed3c04d0e9af1c7cf7b3cc1adb Mon Sep 17 00:00:00 2001 From: David Sterba Date: Wed, 20 Nov 2013 15:05:51 +0100 Subject: Documentation: filesystems: add new btrfs mount options Two new options were added in 3.12: commit and rescan_uuid_tree CC: linux-doc@vger.kernel.org Signed-off-by: David Sterba Signed-off-by: Chris Mason --- Documentation/filesystems/btrfs.txt | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/filesystems/btrfs.txt b/Documentation/filesystems/btrfs.txt index 9dae59407437..4ced8be43c88 100644 --- a/Documentation/filesystems/btrfs.txt +++ b/Documentation/filesystems/btrfs.txt @@ -70,6 +70,12 @@ Unless otherwise specified, all options default to off. See comments at the top of fs/btrfs/check-integrity.c for more info. + commit= + Set the interval of periodic commit, 30 seconds by default. Higher + values defer data being synced to permanent storage with obvious + consequences when the system crashes. The upper bound is not forced, + but a warning is printed if it's more than 300 seconds (5 minutes). + compress compress= compress-force @@ -154,7 +160,11 @@ Unless otherwise specified, all options default to off. Currently this scans a list of several previous tree roots and tries to use the first readable. - skip_balance + rescan_uuid_tree + Force check and rebuild procedure of the UUID tree. This should not + normally be needed. + + skip_balance Skip automatic resume of interrupted balance operation after mount. May be resumed with "btrfs balance resume." -- cgit v1.2.3 From c75017961ba7df5da148b48a905c97181587d562 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Wed, 20 Nov 2013 15:06:08 +0100 Subject: Documentation: filesystems: update btrfs tools section The tools mentioned have been obsoleted long ago, replace with the current ones. CC: linux-doc@vger.kernel.org Signed-off-by: David Sterba Signed-off-by: Chris Mason --- Documentation/filesystems/btrfs.txt | 22 ++++++---------------- 1 file changed, 6 insertions(+), 16 deletions(-) (limited to 'Documentation') diff --git a/Documentation/filesystems/btrfs.txt b/Documentation/filesystems/btrfs.txt index 4ced8be43c88..5dd282dda55c 100644 --- a/Documentation/filesystems/btrfs.txt +++ b/Documentation/filesystems/btrfs.txt @@ -244,24 +244,14 @@ available from the git repository at the following location: These include the following tools: -mkfs.btrfs: create a filesystem +* mkfs.btrfs: create a filesystem -btrfsctl: control program to create snapshots and subvolumes: +* btrfs: a single tool to manage the filesystems, refer to the manpage for more details - mount /dev/sda2 /mnt - btrfsctl -s new_subvol_name /mnt - btrfsctl -s snapshot_of_default /mnt/default - btrfsctl -s snapshot_of_new_subvol /mnt/new_subvol_name - btrfsctl -s snapshot_of_a_snapshot /mnt/snapshot_of_new_subvol - ls /mnt - default snapshot_of_a_snapshot snapshot_of_new_subvol - new_subvol_name snapshot_of_default +* 'btrfsck' or 'btrfs check': do a consistency check of the filesystem - Snapshots and subvolumes cannot be deleted right now, but you can - rm -rf all the files and directories inside them. +Other tools for specific tasks: -btrfsck: do a limited check of the FS extent trees. +* btrfs-convert: in-place conversion from ext2/3/4 filesystems -btrfs-debug-tree: print all of the FS metadata in text form. Example: - - btrfs-debug-tree /dev/sda2 >& big_output_file +* btrfs-image: dump filesystem metadata for debugging -- cgit v1.2.3 From c283610e44ec4ccc412dde8b71cf297ed9515f2f Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Thu, 21 Nov 2013 14:32:09 -0800 Subject: x86, mm: do not leak page->ptl for pmd page tables There are two code paths how page with pmd page table can be freed: pmd_free() and pmd_free_tlb(). I've missed the second one and didn't add page table destructor call there. It leads to leak of page->ptl for pmd page tables, if dynamically allocated page->ptl is in use. The patch adds the missed destructor and modifies documentation accordingly. Signed-off-by: Kirill A. Shutemov Reported-by: Andrey Vagin Tested-by: Andrey Vagin Cc: Ingo Molnar Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/vm/split_page_table_lock | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/vm/split_page_table_lock b/Documentation/vm/split_page_table_lock index 7521d367f21d..6dea4fd5c961 100644 --- a/Documentation/vm/split_page_table_lock +++ b/Documentation/vm/split_page_table_lock @@ -63,9 +63,9 @@ levels. PMD split lock enabling requires pgtable_pmd_page_ctor() call on PMD table allocation and pgtable_pmd_page_dtor() on freeing. -Allocation usually happens in pmd_alloc_one(), freeing in pmd_free(), but -make sure you cover all PMD table allocation / freeing paths: i.e X86_PAE -preallocate few PMDs on pgd_alloc(). +Allocation usually happens in pmd_alloc_one(), freeing in pmd_free() and +pmd_free_tlb(), but make sure you cover all PMD table allocation / freeing +paths: i.e X86_PAE preallocate few PMDs on pgd_alloc(). With everything in place you can set CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK. -- cgit v1.2.3 From fd8e198cfcaa8abcc7f7525619d447f9a805e86e Mon Sep 17 00:00:00 2001 From: Alexandre Courbot Date: Sat, 16 Nov 2013 21:34:21 +0900 Subject: Documentation: gpiolib: document new interface gpiolib now exports a new descriptor-based interface which deprecates the older integer-based one. This patch documents this new interface and also takes the opportunity to brush-up the GPIO documentation a little bit. The new descriptor-based interface follows the same consumer/driver model as many other kernel subsystems (e.g. clock, regulator), so its documentation has similarly been splitted into different files. The content of the former documentation has been reused whenever it made sense; however, some of its content did not apply to the new interface anymore and have this been removed. Likewise, new sections like the mapping of GPIOs to devices have been written from scratch. The deprecated legacy-based documentation is still available, untouched, under Documentation/gpio/gpio-legacy.txt. Signed-off-by: Alexandre Courbot Signed-off-by: Linus Walleij --- Documentation/gpio.txt | 775 ------------------------------------- Documentation/gpio/board.txt | 115 ++++++ Documentation/gpio/consumer.txt | 197 ++++++++++ Documentation/gpio/driver.txt | 75 ++++ Documentation/gpio/gpio-legacy.txt | 775 +++++++++++++++++++++++++++++++++++++ Documentation/gpio/gpio.txt | 119 ++++++ Documentation/gpio/sysfs.txt | 155 ++++++++ 7 files changed, 1436 insertions(+), 775 deletions(-) delete mode 100644 Documentation/gpio.txt create mode 100644 Documentation/gpio/board.txt create mode 100644 Documentation/gpio/consumer.txt create mode 100644 Documentation/gpio/driver.txt create mode 100644 Documentation/gpio/gpio-legacy.txt create mode 100644 Documentation/gpio/gpio.txt create mode 100644 Documentation/gpio/sysfs.txt (limited to 'Documentation') diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt deleted file mode 100644 index 6f83fa965b4b..000000000000 --- a/Documentation/gpio.txt +++ /dev/null @@ -1,775 +0,0 @@ -GPIO Interfaces - -This provides an overview of GPIO access conventions on Linux. - -These calls use the gpio_* naming prefix. No other calls should use that -prefix, or the related __gpio_* prefix. - - -What is a GPIO? -=============== -A "General Purpose Input/Output" (GPIO) is a flexible software-controlled -digital signal. They are provided from many kinds of chip, and are familiar -to Linux developers working with embedded and custom hardware. Each GPIO -represents a bit connected to a particular pin, or "ball" on Ball Grid Array -(BGA) packages. Board schematics show which external hardware connects to -which GPIOs. Drivers can be written generically, so that board setup code -passes such pin configuration data to drivers. - -System-on-Chip (SOC) processors heavily rely on GPIOs. In some cases, every -non-dedicated pin can be configured as a GPIO; and most chips have at least -several dozen of them. Programmable logic devices (like FPGAs) can easily -provide GPIOs; multifunction chips like power managers, and audio codecs -often have a few such pins to help with pin scarcity on SOCs; and there are -also "GPIO Expander" chips that connect using the I2C or SPI serial busses. -Most PC southbridges have a few dozen GPIO-capable pins (with only the BIOS -firmware knowing how they're used). - -The exact capabilities of GPIOs vary between systems. Common options: - - - Output values are writable (high=1, low=0). Some chips also have - options about how that value is driven, so that for example only one - value might be driven ... supporting "wire-OR" and similar schemes - for the other value (notably, "open drain" signaling). - - - Input values are likewise readable (1, 0). Some chips support readback - of pins configured as "output", which is very useful in such "wire-OR" - cases (to support bidirectional signaling). GPIO controllers may have - input de-glitch/debounce logic, sometimes with software controls. - - - Inputs can often be used as IRQ signals, often edge triggered but - sometimes level triggered. Such IRQs may be configurable as system - wakeup events, to wake the system from a low power state. - - - Usually a GPIO will be configurable as either input or output, as needed - by different product boards; single direction ones exist too. - - - Most GPIOs can be accessed while holding spinlocks, but those accessed - through a serial bus normally can't. Some systems support both types. - -On a given board each GPIO is used for one specific purpose like monitoring -MMC/SD card insertion/removal, detecting card writeprotect status, driving -a LED, configuring a transceiver, bitbanging a serial bus, poking a hardware -watchdog, sensing a switch, and so on. - - -GPIO conventions -================ -Note that this is called a "convention" because you don't need to do it this -way, and it's no crime if you don't. There **are** cases where portability -is not the main issue; GPIOs are often used for the kind of board-specific -glue logic that may even change between board revisions, and can't ever be -used on a board that's wired differently. Only least-common-denominator -functionality can be very portable. Other features are platform-specific, -and that can be critical for glue logic. - -Plus, this doesn't require any implementation framework, just an interface. -One platform might implement it as simple inline functions accessing chip -registers; another might implement it by delegating through abstractions -used for several very different kinds of GPIO controller. (There is some -optional code supporting such an implementation strategy, described later -in this document, but drivers acting as clients to the GPIO interface must -not care how it's implemented.) - -That said, if the convention is supported on their platform, drivers should -use it when possible. Platforms must select ARCH_REQUIRE_GPIOLIB or -ARCH_WANT_OPTIONAL_GPIOLIB in their Kconfig. Drivers that can't work without -standard GPIO calls should have Kconfig entries which depend on GPIOLIB. The -GPIO calls are available, either as "real code" or as optimized-away stubs, -when drivers use the include file: - - #include - -If you stick to this convention then it'll be easier for other developers to -see what your code is doing, and help maintain it. - -Note that these operations include I/O barriers on platforms which need to -use them; drivers don't need to add them explicitly. - - -Identifying GPIOs ------------------ -GPIOs are identified by unsigned integers in the range 0..MAX_INT. That -reserves "negative" numbers for other purposes like marking signals as -"not available on this board", or indicating faults. Code that doesn't -touch the underlying hardware treats these integers as opaque cookies. - -Platforms define how they use those integers, and usually #define symbols -for the GPIO lines so that board-specific setup code directly corresponds -to the relevant schematics. In contrast, drivers should only use GPIO -numbers passed to them from that setup code, using platform_data to hold -board-specific pin configuration data (along with other board specific -data they need). That avoids portability problems. - -So for example one platform uses numbers 32-159 for GPIOs; while another -uses numbers 0..63 with one set of GPIO controllers, 64-79 with another -type of GPIO controller, and on one particular board 80-95 with an FPGA. -The numbers need not be contiguous; either of those platforms could also -use numbers 2000-2063 to identify GPIOs in a bank of I2C GPIO expanders. - -If you want to initialize a structure with an invalid GPIO number, use -some negative number (perhaps "-EINVAL"); that will never be valid. To -test if such number from such a structure could reference a GPIO, you -may use this predicate: - - int gpio_is_valid(int number); - -A number that's not valid will be rejected by calls which may request -or free GPIOs (see below). Other numbers may also be rejected; for -example, a number might be valid but temporarily unused on a given board. - -Whether a platform supports multiple GPIO controllers is a platform-specific -implementation issue, as are whether that support can leave "holes" in the space -of GPIO numbers, and whether new controllers can be added at runtime. Such issues -can affect things including whether adjacent GPIO numbers are both valid. - -Using GPIOs ------------ -The first thing a system should do with a GPIO is allocate it, using -the gpio_request() call; see later. - -One of the next things to do with a GPIO, often in board setup code when -setting up a platform_device using the GPIO, is mark its direction: - - /* set as input or output, returning 0 or negative errno */ - int gpio_direction_input(unsigned gpio); - int gpio_direction_output(unsigned gpio, int value); - -The return value is zero for success, else a negative errno. It should -be checked, since the get/set calls don't have error returns and since -misconfiguration is possible. You should normally issue these calls from -a task context. However, for spinlock-safe GPIOs it's OK to use them -before tasking is enabled, as part of early board setup. - -For output GPIOs, the value provided becomes the initial output value. -This helps avoid signal glitching during system startup. - -For compatibility with legacy interfaces to GPIOs, setting the direction -of a GPIO implicitly requests that GPIO (see below) if it has not been -requested already. That compatibility is being removed from the optional -gpiolib framework. - -Setting the direction can fail if the GPIO number is invalid, or when -that particular GPIO can't be used in that mode. It's generally a bad -idea to rely on boot firmware to have set the direction correctly, since -it probably wasn't validated to do more than boot Linux. (Similarly, -that board setup code probably needs to multiplex that pin as a GPIO, -and configure pullups/pulldowns appropriately.) - - -Spinlock-Safe GPIO access -------------------------- -Most GPIO controllers can be accessed with memory read/write instructions. -Those don't need to sleep, and can safely be done from inside hard -(nonthreaded) IRQ handlers and similar contexts. - -Use the following calls to access such GPIOs, -for which gpio_cansleep() will always return false (see below): - - /* GPIO INPUT: return zero or nonzero */ - int gpio_get_value(unsigned gpio); - - /* GPIO OUTPUT */ - void gpio_set_value(unsigned gpio, int value); - -The values are boolean, zero for low, nonzero for high. When reading the -value of an output pin, the value returned should be what's seen on the -pin ... that won't always match the specified output value, because of -issues including open-drain signaling and output latencies. - -The get/set calls have no error returns because "invalid GPIO" should have -been reported earlier from gpio_direction_*(). However, note that not all -platforms can read the value of output pins; those that can't should always -return zero. Also, using these calls for GPIOs that can't safely be accessed -without sleeping (see below) is an error. - -Platform-specific implementations are encouraged to optimize the two -calls to access the GPIO value in cases where the GPIO number (and for -output, value) are constant. It's normal for them to need only a couple -of instructions in such cases (reading or writing a hardware register), -and not to need spinlocks. Such optimized calls can make bitbanging -applications a lot more efficient (in both space and time) than spending -dozens of instructions on subroutine calls. - - -GPIO access that may sleep --------------------------- -Some GPIO controllers must be accessed using message based busses like I2C -or SPI. Commands to read or write those GPIO values require waiting to -get to the head of a queue to transmit a command and get its response. -This requires sleeping, which can't be done from inside IRQ handlers. - -Platforms that support this type of GPIO distinguish them from other GPIOs -by returning nonzero from this call (which requires a valid GPIO number, -which should have been previously allocated with gpio_request): - - int gpio_cansleep(unsigned gpio); - -To access such GPIOs, a different set of accessors is defined: - - /* GPIO INPUT: return zero or nonzero, might sleep */ - int gpio_get_value_cansleep(unsigned gpio); - - /* GPIO OUTPUT, might sleep */ - void gpio_set_value_cansleep(unsigned gpio, int value); - - -Accessing such GPIOs requires a context which may sleep, for example -a threaded IRQ handler, and those accessors must be used instead of -spinlock-safe accessors without the cansleep() name suffix. - -Other than the fact that these accessors might sleep, and will work -on GPIOs that can't be accessed from hardIRQ handlers, these calls act -the same as the spinlock-safe calls. - - ** IN ADDITION ** calls to setup and configure such GPIOs must be made -from contexts which may sleep, since they may need to access the GPIO -controller chip too: (These setup calls are usually made from board -setup or driver probe/teardown code, so this is an easy constraint.) - - gpio_direction_input() - gpio_direction_output() - gpio_request() - -## gpio_request_one() -## gpio_request_array() -## gpio_free_array() - - gpio_free() - gpio_set_debounce() - - - -Claiming and Releasing GPIOs ----------------------------- -To help catch system configuration errors, two calls are defined. - - /* request GPIO, returning 0 or negative errno. - * non-null labels may be useful for diagnostics. - */ - int gpio_request(unsigned gpio, const char *label); - - /* release previously-claimed GPIO */ - void gpio_free(unsigned gpio); - -Passing invalid GPIO numbers to gpio_request() will fail, as will requesting -GPIOs that have already been claimed with that call. The return value of -gpio_request() must be checked. You should normally issue these calls from -a task context. However, for spinlock-safe GPIOs it's OK to request GPIOs -before tasking is enabled, as part of early board setup. - -These calls serve two basic purposes. One is marking the signals which -are actually in use as GPIOs, for better diagnostics; systems may have -several hundred potential GPIOs, but often only a dozen are used on any -given board. Another is to catch conflicts, identifying errors when -(a) two or more drivers wrongly think they have exclusive use of that -signal, or (b) something wrongly believes it's safe to remove drivers -needed to manage a signal that's in active use. That is, requesting a -GPIO can serve as a kind of lock. - -Some platforms may also use knowledge about what GPIOs are active for -power management, such as by powering down unused chip sectors and, more -easily, gating off unused clocks. - -For GPIOs that use pins known to the pinctrl subsystem, that subsystem should -be informed of their use; a gpiolib driver's .request() operation may call -pinctrl_request_gpio(), and a gpiolib driver's .free() operation may call -pinctrl_free_gpio(). The pinctrl subsystem allows a pinctrl_request_gpio() -to succeed concurrently with a pin or pingroup being "owned" by a device for -pin multiplexing. - -Any programming of pin multiplexing hardware that is needed to route the -GPIO signal to the appropriate pin should occur within a GPIO driver's -.direction_input() or .direction_output() operations, and occur after any -setup of an output GPIO's value. This allows a glitch-free migration from a -pin's special function to GPIO. This is sometimes required when using a GPIO -to implement a workaround on signals typically driven by a non-GPIO HW block. - -Some platforms allow some or all GPIO signals to be routed to different pins. -Similarly, other aspects of the GPIO or pin may need to be configured, such as -pullup/pulldown. Platform software should arrange that any such details are -configured prior to gpio_request() being called for those GPIOs, e.g. using -the pinctrl subsystem's mapping table, so that GPIO users need not be aware -of these details. - -Also note that it's your responsibility to have stopped using a GPIO -before you free it. - -Considering in most cases GPIOs are actually configured right after they -are claimed, three additional calls are defined: - - /* request a single GPIO, with initial configuration specified by - * 'flags', identical to gpio_request() wrt other arguments and - * return value - */ - int gpio_request_one(unsigned gpio, unsigned long flags, const char *label); - - /* request multiple GPIOs in a single call - */ - int gpio_request_array(struct gpio *array, size_t num); - - /* release multiple GPIOs in a single call - */ - void gpio_free_array(struct gpio *array, size_t num); - -where 'flags' is currently defined to specify the following properties: - - * GPIOF_DIR_IN - to configure direction as input - * GPIOF_DIR_OUT - to configure direction as output - - * GPIOF_INIT_LOW - as output, set initial level to LOW - * GPIOF_INIT_HIGH - as output, set initial level to HIGH - * GPIOF_OPEN_DRAIN - gpio pin is open drain type. - * GPIOF_OPEN_SOURCE - gpio pin is open source type. - - * GPIOF_EXPORT_DIR_FIXED - export gpio to sysfs, keep direction - * GPIOF_EXPORT_DIR_CHANGEABLE - also export, allow changing direction - -since GPIOF_INIT_* are only valid when configured as output, so group valid -combinations as: - - * GPIOF_IN - configure as input - * GPIOF_OUT_INIT_LOW - configured as output, initial level LOW - * GPIOF_OUT_INIT_HIGH - configured as output, initial level HIGH - -When setting the flag as GPIOF_OPEN_DRAIN then it will assume that pins is -open drain type. Such pins will not be driven to 1 in output mode. It is -require to connect pull-up on such pins. By enabling this flag, gpio lib will -make the direction to input when it is asked to set value of 1 in output mode -to make the pin HIGH. The pin is make to LOW by driving value 0 in output mode. - -When setting the flag as GPIOF_OPEN_SOURCE then it will assume that pins is -open source type. Such pins will not be driven to 0 in output mode. It is -require to connect pull-down on such pin. By enabling this flag, gpio lib will -make the direction to input when it is asked to set value of 0 in output mode -to make the pin LOW. The pin is make to HIGH by driving value 1 in output mode. - -In the future, these flags can be extended to support more properties. - -Further more, to ease the claim/release of multiple GPIOs, 'struct gpio' is -introduced to encapsulate all three fields as: - - struct gpio { - unsigned gpio; - unsigned long flags; - const char *label; - }; - -A typical example of usage: - - static struct gpio leds_gpios[] = { - { 32, GPIOF_OUT_INIT_HIGH, "Power LED" }, /* default to ON */ - { 33, GPIOF_OUT_INIT_LOW, "Green LED" }, /* default to OFF */ - { 34, GPIOF_OUT_INIT_LOW, "Red LED" }, /* default to OFF */ - { 35, GPIOF_OUT_INIT_LOW, "Blue LED" }, /* default to OFF */ - { ... }, - }; - - err = gpio_request_one(31, GPIOF_IN, "Reset Button"); - if (err) - ... - - err = gpio_request_array(leds_gpios, ARRAY_SIZE(leds_gpios)); - if (err) - ... - - gpio_free_array(leds_gpios, ARRAY_SIZE(leds_gpios)); - - -GPIOs mapped to IRQs --------------------- -GPIO numbers are unsigned integers; so are IRQ numbers. These make up -two logically distinct namespaces (GPIO 0 need not use IRQ 0). You can -map between them using calls like: - - /* map GPIO numbers to IRQ numbers */ - int gpio_to_irq(unsigned gpio); - - /* map IRQ numbers to GPIO numbers (avoid using this) */ - int irq_to_gpio(unsigned irq); - -Those return either the corresponding number in the other namespace, or -else a negative errno code if the mapping can't be done. (For example, -some GPIOs can't be used as IRQs.) It is an unchecked error to use a GPIO -number that wasn't set up as an input using gpio_direction_input(), or -to use an IRQ number that didn't originally come from gpio_to_irq(). - -These two mapping calls are expected to cost on the order of a single -addition or subtraction. They're not allowed to sleep. - -Non-error values returned from gpio_to_irq() can be passed to request_irq() -or free_irq(). They will often be stored into IRQ resources for platform -devices, by the board-specific initialization code. Note that IRQ trigger -options are part of the IRQ interface, e.g. IRQF_TRIGGER_FALLING, as are -system wakeup capabilities. - -Non-error values returned from irq_to_gpio() would most commonly be used -with gpio_get_value(), for example to initialize or update driver state -when the IRQ is edge-triggered. Note that some platforms don't support -this reverse mapping, so you should avoid using it. - - -Emulating Open Drain Signals ----------------------------- -Sometimes shared signals need to use "open drain" signaling, where only the -low signal level is actually driven. (That term applies to CMOS transistors; -"open collector" is used for TTL.) A pullup resistor causes the high signal -level. This is sometimes called a "wire-AND"; or more practically, from the -negative logic (low=true) perspective this is a "wire-OR". - -One common example of an open drain signal is a shared active-low IRQ line. -Also, bidirectional data bus signals sometimes use open drain signals. - -Some GPIO controllers directly support open drain outputs; many don't. When -you need open drain signaling but your hardware doesn't directly support it, -there's a common idiom you can use to emulate it with any GPIO pin that can -be used as either an input or an output: - - LOW: gpio_direction_output(gpio, 0) ... this drives the signal - and overrides the pullup. - - HIGH: gpio_direction_input(gpio) ... this turns off the output, - so the pullup (or some other device) controls the signal. - -If you are "driving" the signal high but gpio_get_value(gpio) reports a low -value (after the appropriate rise time passes), you know some other component -is driving the shared signal low. That's not necessarily an error. As one -common example, that's how I2C clocks are stretched: a slave that needs a -slower clock delays the rising edge of SCK, and the I2C master adjusts its -signaling rate accordingly. - - -GPIO controllers and the pinctrl subsystem ------------------------------------------- - -A GPIO controller on a SOC might be tightly coupled with the pinctrl -subsystem, in the sense that the pins can be used by other functions -together with an optional gpio feature. We have already covered the -case where e.g. a GPIO controller need to reserve a pin or set the -direction of a pin by calling any of: - -pinctrl_request_gpio() -pinctrl_free_gpio() -pinctrl_gpio_direction_input() -pinctrl_gpio_direction_output() - -But how does the pin control subsystem cross-correlate the GPIO -numbers (which are a global business) to a certain pin on a certain -pin controller? - -This is done by registering "ranges" of pins, which are essentially -cross-reference tables. These are described in -Documentation/pinctrl.txt - -While the pin allocation is totally managed by the pinctrl subsystem, -gpio (under gpiolib) is still maintained by gpio drivers. It may happen -that different pin ranges in a SoC is managed by different gpio drivers. - -This makes it logical to let gpio drivers announce their pin ranges to -the pin ctrl subsystem before it will call 'pinctrl_request_gpio' in order -to request the corresponding pin to be prepared by the pinctrl subsystem -before any gpio usage. - -For this, the gpio controller can register its pin range with pinctrl -subsystem. There are two ways of doing it currently: with or without DT. - -For with DT support refer to Documentation/devicetree/bindings/gpio/gpio.txt. - -For non-DT support, user can call gpiochip_add_pin_range() with appropriate -parameters to register a range of gpio pins with a pinctrl driver. For this -exact name string of pinctrl device has to be passed as one of the -argument to this routine. - - -What do these conventions omit? -=============================== -One of the biggest things these conventions omit is pin multiplexing, since -this is highly chip-specific and nonportable. One platform might not need -explicit multiplexing; another might have just two options for use of any -given pin; another might have eight options per pin; another might be able -to route a given GPIO to any one of several pins. (Yes, those examples all -come from systems that run Linux today.) - -Related to multiplexing is configuration and enabling of the pullups or -pulldowns integrated on some platforms. Not all platforms support them, -or support them in the same way; and any given board might use external -pullups (or pulldowns) so that the on-chip ones should not be used. -(When a circuit needs 5 kOhm, on-chip 100 kOhm resistors won't do.) -Likewise drive strength (2 mA vs 20 mA) and voltage (1.8V vs 3.3V) is a -platform-specific issue, as are models like (not) having a one-to-one -correspondence between configurable pins and GPIOs. - -There are other system-specific mechanisms that are not specified here, -like the aforementioned options for input de-glitching and wire-OR output. -Hardware may support reading or writing GPIOs in gangs, but that's usually -configuration dependent: for GPIOs sharing the same bank. (GPIOs are -commonly grouped in banks of 16 or 32, with a given SOC having several such -banks.) Some systems can trigger IRQs from output GPIOs, or read values -from pins not managed as GPIOs. Code relying on such mechanisms will -necessarily be nonportable. - -Dynamic definition of GPIOs is not currently standard; for example, as -a side effect of configuring an add-on board with some GPIO expanders. - - -GPIO implementor's framework (OPTIONAL) -======================================= -As noted earlier, there is an optional implementation framework making it -easier for platforms to support different kinds of GPIO controller using -the same programming interface. This framework is called "gpiolib". - -As a debugging aid, if debugfs is available a /sys/kernel/debug/gpio file -will be found there. That will list all the controllers registered through -this framework, and the state of the GPIOs currently in use. - - -Controller Drivers: gpio_chip ------------------------------ -In this framework each GPIO controller is packaged as a "struct gpio_chip" -with information common to each controller of that type: - - - methods to establish GPIO direction - - methods used to access GPIO values - - flag saying whether calls to its methods may sleep - - optional debugfs dump method (showing extra state like pullup config) - - label for diagnostics - -There is also per-instance data, which may come from device.platform_data: -the number of its first GPIO, and how many GPIOs it exposes. - -The code implementing a gpio_chip should support multiple instances of the -controller, possibly using the driver model. That code will configure each -gpio_chip and issue gpiochip_add(). Removing a GPIO controller should be -rare; use gpiochip_remove() when it is unavoidable. - -Most often a gpio_chip is part of an instance-specific structure with state -not exposed by the GPIO interfaces, such as addressing, power management, -and more. Chips such as codecs will have complex non-GPIO state. - -Any debugfs dump method should normally ignore signals which haven't been -requested as GPIOs. They can use gpiochip_is_requested(), which returns -either NULL or the label associated with that GPIO when it was requested. - - -Platform Support ----------------- -To support this framework, a platform's Kconfig will "select" either -ARCH_REQUIRE_GPIOLIB or ARCH_WANT_OPTIONAL_GPIOLIB -and arrange that its includes and defines -three functions: gpio_get_value(), gpio_set_value(), and gpio_cansleep(). - -It may also provide a custom value for ARCH_NR_GPIOS, so that it better -reflects the number of GPIOs in actual use on that platform, without -wasting static table space. (It should count both built-in/SoC GPIOs and -also ones on GPIO expanders. - -ARCH_REQUIRE_GPIOLIB means that the gpiolib code will always get compiled -into the kernel on that architecture. - -ARCH_WANT_OPTIONAL_GPIOLIB means the gpiolib code defaults to off and the user -can enable it and build it into the kernel optionally. - -If neither of these options are selected, the platform does not support -GPIOs through GPIO-lib and the code cannot be enabled by the user. - -Trivial implementations of those functions can directly use framework -code, which always dispatches through the gpio_chip: - - #define gpio_get_value __gpio_get_value - #define gpio_set_value __gpio_set_value - #define gpio_cansleep __gpio_cansleep - -Fancier implementations could instead define those as inline functions with -logic optimizing access to specific SOC-based GPIOs. For example, if the -referenced GPIO is the constant "12", getting or setting its value could -cost as little as two or three instructions, never sleeping. When such an -optimization is not possible those calls must delegate to the framework -code, costing at least a few dozen instructions. For bitbanged I/O, such -instruction savings can be significant. - -For SOCs, platform-specific code defines and registers gpio_chip instances -for each bank of on-chip GPIOs. Those GPIOs should be numbered/labeled to -match chip vendor documentation, and directly match board schematics. They -may well start at zero and go up to a platform-specific limit. Such GPIOs -are normally integrated into platform initialization to make them always be -available, from arch_initcall() or earlier; they can often serve as IRQs. - - -Board Support -------------- -For external GPIO controllers -- such as I2C or SPI expanders, ASICs, multi -function devices, FPGAs or CPLDs -- most often board-specific code handles -registering controller devices and ensures that their drivers know what GPIO -numbers to use with gpiochip_add(). Their numbers often start right after -platform-specific GPIOs. - -For example, board setup code could create structures identifying the range -of GPIOs that chip will expose, and passes them to each GPIO expander chip -using platform_data. Then the chip driver's probe() routine could pass that -data to gpiochip_add(). - -Initialization order can be important. For example, when a device relies on -an I2C-based GPIO, its probe() routine should only be called after that GPIO -becomes available. That may mean the device should not be registered until -calls for that GPIO can work. One way to address such dependencies is for -such gpio_chip controllers to provide setup() and teardown() callbacks to -board specific code; those board specific callbacks would register devices -once all the necessary resources are available, and remove them later when -the GPIO controller device becomes unavailable. - - -Sysfs Interface for Userspace (OPTIONAL) -======================================== -Platforms which use the "gpiolib" implementors framework may choose to -configure a sysfs user interface to GPIOs. This is different from the -debugfs interface, since it provides control over GPIO direction and -value instead of just showing a gpio state summary. Plus, it could be -present on production systems without debugging support. - -Given appropriate hardware documentation for the system, userspace could -know for example that GPIO #23 controls the write protect line used to -protect boot loader segments in flash memory. System upgrade procedures -may need to temporarily remove that protection, first importing a GPIO, -then changing its output state, then updating the code before re-enabling -the write protection. In normal use, GPIO #23 would never be touched, -and the kernel would have no need to know about it. - -Again depending on appropriate hardware documentation, on some systems -userspace GPIO can be used to determine system configuration data that -standard kernels won't know about. And for some tasks, simple userspace -GPIO drivers could be all that the system really needs. - -Note that standard kernel drivers exist for common "LEDs and Buttons" -GPIO tasks: "leds-gpio" and "gpio_keys", respectively. Use those -instead of talking directly to the GPIOs; they integrate with kernel -frameworks better than your userspace code could. - - -Paths in Sysfs --------------- -There are three kinds of entry in /sys/class/gpio: - - - Control interfaces used to get userspace control over GPIOs; - - - GPIOs themselves; and - - - GPIO controllers ("gpio_chip" instances). - -That's in addition to standard files including the "device" symlink. - -The control interfaces are write-only: - - /sys/class/gpio/ - - "export" ... Userspace may ask the kernel to export control of - a GPIO to userspace by writing its number to this file. - - Example: "echo 19 > export" will create a "gpio19" node - for GPIO #19, if that's not requested by kernel code. - - "unexport" ... Reverses the effect of exporting to userspace. - - Example: "echo 19 > unexport" will remove a "gpio19" - node exported using the "export" file. - -GPIO signals have paths like /sys/class/gpio/gpio42/ (for GPIO #42) -and have the following read/write attributes: - - /sys/class/gpio/gpioN/ - - "direction" ... reads as either "in" or "out". This value may - normally be written. Writing as "out" defaults to - initializing the value as low. To ensure glitch free - operation, values "low" and "high" may be written to - configure the GPIO as an output with that initial value. - - Note that this attribute *will not exist* if the kernel - doesn't support changing the direction of a GPIO, or - it was exported by kernel code that didn't explicitly - allow userspace to reconfigure this GPIO's direction. - - "value" ... reads as either 0 (low) or 1 (high). If the GPIO - is configured as an output, this value may be written; - any nonzero value is treated as high. - - If the pin can be configured as interrupt-generating interrupt - and if it has been configured to generate interrupts (see the - description of "edge"), you can poll(2) on that file and - poll(2) will return whenever the interrupt was triggered. If - you use poll(2), set the events POLLPRI and POLLERR. If you - use select(2), set the file descriptor in exceptfds. After - poll(2) returns, either lseek(2) to the beginning of the sysfs - file and read the new value or close the file and re-open it - to read the value. - - "edge" ... reads as either "none", "rising", "falling", or - "both". Write these strings to select the signal edge(s) - that will make poll(2) on the "value" file return. - - This file exists only if the pin can be configured as an - interrupt generating input pin. - - "active_low" ... reads as either 0 (false) or 1 (true). Write - any nonzero value to invert the value attribute both - for reading and writing. Existing and subsequent - poll(2) support configuration via the edge attribute - for "rising" and "falling" edges will follow this - setting. - -GPIO controllers have paths like /sys/class/gpio/gpiochip42/ (for the -controller implementing GPIOs starting at #42) and have the following -read-only attributes: - - /sys/class/gpio/gpiochipN/ - - "base" ... same as N, the first GPIO managed by this chip - - "label" ... provided for diagnostics (not always unique) - - "ngpio" ... how many GPIOs this manges (N to N + ngpio - 1) - -Board documentation should in most cases cover what GPIOs are used for -what purposes. However, those numbers are not always stable; GPIOs on -a daughtercard might be different depending on the base board being used, -or other cards in the stack. In such cases, you may need to use the -gpiochip nodes (possibly in conjunction with schematics) to determine -the correct GPIO number to use for a given signal. - - -Exporting from Kernel code --------------------------- -Kernel code can explicitly manage exports of GPIOs which have already been -requested using gpio_request(): - - /* export the GPIO to userspace */ - int gpio_export(unsigned gpio, bool direction_may_change); - - /* reverse gpio_export() */ - void gpio_unexport(); - - /* create a sysfs link to an exported GPIO node */ - int gpio_export_link(struct device *dev, const char *name, - unsigned gpio) - - /* change the polarity of a GPIO node in sysfs */ - int gpio_sysfs_set_active_low(unsigned gpio, int value); - -After a kernel driver requests a GPIO, it may only be made available in -the sysfs interface by gpio_export(). The driver can control whether the -signal direction may change. This helps drivers prevent userspace code -from accidentally clobbering important system state. - -This explicit exporting can help with debugging (by making some kinds -of experiments easier), or can provide an always-there interface that's -suitable for documenting as part of a board support package. - -After the GPIO has been exported, gpio_export_link() allows creating -symlinks from elsewhere in sysfs to the GPIO sysfs node. Drivers can -use this to provide the interface under their own device in sysfs with -a descriptive name. - -Drivers can use gpio_sysfs_set_active_low() to hide GPIO line polarity -differences between boards from user space. This only affects the -sysfs interface. Polarity change can be done both before and after -gpio_export(), and previously enabled poll(2) support for either -rising or falling edge will be reconfigured to follow this setting. diff --git a/Documentation/gpio/board.txt b/Documentation/gpio/board.txt new file mode 100644 index 000000000000..0d03506f2cc5 --- /dev/null +++ b/Documentation/gpio/board.txt @@ -0,0 +1,115 @@ +GPIO Mappings +============= + +This document explains how GPIOs can be assigned to given devices and functions. +Note that it only applies to the new descriptor-based interface. For a +description of the deprecated integer-based GPIO interface please refer to +gpio-legacy.txt (actually, there is no real mapping possible with the old +interface; you just fetch an integer from somewhere and request the +corresponding GPIO. + +Platforms that make use of GPIOs must select ARCH_REQUIRE_GPIOLIB (if GPIO usage +is mandatory) or ARCH_WANT_OPTIONAL_GPIOLIB (if GPIO support can be omitted) in +their Kconfig. Then, how GPIOs are mapped depends on what the platform uses to +describe its hardware layout. Currently, mappings can be defined through device +tree, ACPI, and platform data. + +Device Tree +----------- +GPIOs can easily be mapped to devices and functions in the device tree. The +exact way to do it depends on the GPIO controller providing the GPIOs, see the +device tree bindings for your controller. + +GPIOs mappings are defined in the consumer device's node, in a property named +-gpios, where is the function the driver will request +through gpiod_get(). For example: + + foo_device { + compatible = "acme,foo"; + ... + led-gpios = <&gpio 15 GPIO_ACTIVE_HIGH>, /* red */ + <&gpio 16 GPIO_ACTIVE_HIGH>, /* green */ + <&gpio 17 GPIO_ACTIVE_HIGH>; /* blue */ + + power-gpio = <&gpio 1 GPIO_ACTIVE_LOW>; + }; + +This property will make GPIOs 15, 16 and 17 available to the driver under the +"led" function, and GPIO 1 as the "power" GPIO: + + struct gpio_desc *red, *green, *blue, *power; + + red = gpiod_get_index(dev, "led", 0); + green = gpiod_get_index(dev, "led", 1); + blue = gpiod_get_index(dev, "led", 2); + + power = gpiod_get(dev, "power"); + +The led GPIOs will be active-high, while the power GPIO will be active-low (i.e. +gpiod_is_active_low(power) will be true). + +ACPI +---- +ACPI does not support function names for GPIOs. Therefore, only the "idx" +argument of gpiod_get_index() is useful to discriminate between GPIOs assigned +to a device. The "con_id" argument can still be set for debugging purposes (it +will appear under error messages as well as debug and sysfs nodes). + +Platform Data +------------- +Finally, GPIOs can be bound to devices and functions using platform data. Board +files that desire to do so need to include the following header: + + #include + +GPIOs are mapped by the means of tables of lookups, containing instances of the +gpiod_lookup structure. Two macros are defined to help declaring such mappings: + + GPIO_LOOKUP(chip_label, chip_hwnum, dev_id, con_id, flags) + GPIO_LOOKUP_IDX(chip_label, chip_hwnum, dev_id, con_id, idx, flags) + +where + + - chip_label is the label of the gpiod_chip instance providing the GPIO + - chip_hwnum is the hardware number of the GPIO within the chip + - dev_id is the identifier of the device that will make use of this GPIO. If + NULL, the GPIO will be available to all devices. + - con_id is the name of the GPIO function from the device point of view. It + can be NULL. + - idx is the index of the GPIO within the function. + - flags is defined to specify the following properties: + * GPIOF_ACTIVE_LOW - to configure the GPIO as active-low + * GPIOF_OPEN_DRAIN - GPIO pin is open drain type. + * GPIOF_OPEN_SOURCE - GPIO pin is open source type. + +In the future, these flags might be extended to support more properties. + +Note that GPIO_LOOKUP() is just a shortcut to GPIO_LOOKUP_IDX() where idx = 0. + +A lookup table can then be defined as follows: + + struct gpiod_lookup gpios_table[] = { + GPIO_LOOKUP_IDX("gpio.0", 15, "foo.0", "led", 0, GPIO_ACTIVE_HIGH), + GPIO_LOOKUP_IDX("gpio.0", 16, "foo.0", "led", 1, GPIO_ACTIVE_HIGH), + GPIO_LOOKUP_IDX("gpio.0", 17, "foo.0", "led", 2, GPIO_ACTIVE_HIGH), + GPIO_LOOKUP("gpio.0", 1, "foo.0", "power", GPIO_ACTIVE_LOW), + }; + +And the table can be added by the board code as follows: + + gpiod_add_table(gpios_table, ARRAY_SIZE(gpios_table)); + +The driver controlling "foo.0" will then be able to obtain its GPIOs as follows: + + struct gpio_desc *red, *green, *blue, *power; + + red = gpiod_get_index(dev, "led", 0); + green = gpiod_get_index(dev, "led", 1); + blue = gpiod_get_index(dev, "led", 2); + + power = gpiod_get(dev, "power"); + gpiod_direction_output(power, 1); + +Since the "power" GPIO is mapped as active-low, its actual signal will be 0 +after this code. Contrary to the legacy integer GPIO interface, the active-low +property is handled during mapping and is thus transparent to GPIO consumers. diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt new file mode 100644 index 000000000000..07c74a3765a0 --- /dev/null +++ b/Documentation/gpio/consumer.txt @@ -0,0 +1,197 @@ +GPIO Descriptor Consumer Interface +================================== + +This document describes the consumer interface of the GPIO framework. Note that +it describes the new descriptor-based interface. For a description of the +deprecated integer-based GPIO interface please refer to gpio-legacy.txt. + + +Guidelines for GPIOs consumers +============================== + +Drivers that can't work without standard GPIO calls should have Kconfig entries +that depend on GPIOLIB. The functions that allow a driver to obtain and use +GPIOs are available by including the following file: + + #include + +All the functions that work with the descriptor-based GPIO interface are +prefixed with gpiod_. The gpio_ prefix is used for the legacy interface. No +other function in the kernel should use these prefixes. + + +Obtaining and Disposing GPIOs +============================= + +With the descriptor-based interface, GPIOs are identified with an opaque, +non-forgeable handler that must be obtained through a call to one of the +gpiod_get() functions. Like many other kernel subsystems, gpiod_get() takes the +device that will use the GPIO and the function the requested GPIO is supposed to +fulfill: + + struct gpio_desc *gpiod_get(struct device *dev, const char *con_id) + +If a function is implemented by using several GPIOs together (e.g. a simple LED +device that displays digits), an additional index argument can be specified: + + struct gpio_desc *gpiod_get_index(struct device *dev, + const char *con_id, unsigned int idx) + +Both functions return either a valid GPIO descriptor, or an error code checkable +with IS_ERR(). They will never return a NULL pointer. + +Device-managed variants of these functions are also defined: + + struct gpio_desc *devm_gpiod_get(struct device *dev, const char *con_id) + + struct gpio_desc *devm_gpiod_get_index(struct device *dev, + const char *con_id, + unsigned int idx) + +A GPIO descriptor can be disposed of using the gpiod_put() function: + + void gpiod_put(struct gpio_desc *desc) + +It is strictly forbidden to use a descriptor after calling this function. The +device-managed variant is, unsurprisingly: + + void devm_gpiod_put(struct device *dev, struct gpio_desc *desc) + + +Using GPIOs +=========== + +Setting Direction +----------------- +The first thing a driver must do with a GPIO is setting its direction. This is +done by invoking one of the gpiod_direction_*() functions: + + int gpiod_direction_input(struct gpio_desc *desc) + int gpiod_direction_output(struct gpio_desc *desc, int value) + +The return value is zero for success, else a negative errno. It should be +checked, since the get/set calls don't return errors and since misconfiguration +is possible. You should normally issue these calls from a task context. However, +for spinlock-safe GPIOs it is OK to use them before tasking is enabled, as part +of early board setup. + +For output GPIOs, the value provided becomes the initial output value. This +helps avoid signal glitching during system startup. + +A driver can also query the current direction of a GPIO: + + int gpiod_get_direction(const struct gpio_desc *desc) + +This function will return either GPIOF_DIR_IN or GPIOF_DIR_OUT. + +Be aware that there is no default direction for GPIOs. Therefore, **using a GPIO +without setting its direction first is illegal and will result in undefined +behavior!** + + +Spinlock-Safe GPIO Access +------------------------- +Most GPIO controllers can be accessed with memory read/write instructions. Those +don't need to sleep, and can safely be done from inside hard (non-threaded) IRQ +handlers and similar contexts. + +Use the following calls to access GPIOs from an atomic context: + + int gpiod_get_value(const struct gpio_desc *desc); + void gpiod_set_value(struct gpio_desc *desc, int value); + +The values are boolean, zero for low, nonzero for high. When reading the value +of an output pin, the value returned should be what's seen on the pin. That +won't always match the specified output value, because of issues including +open-drain signaling and output latencies. + +The get/set calls do not return errors because "invalid GPIO" should have been +reported earlier from gpiod_direction_*(). However, note that not all platforms +can read the value of output pins; those that can't should always return zero. +Also, using these calls for GPIOs that can't safely be accessed without sleeping +(see below) is an error. + + +GPIO Access That May Sleep +-------------------------- +Some GPIO controllers must be accessed using message based buses like I2C or +SPI. Commands to read or write those GPIO values require waiting to get to the +head of a queue to transmit a command and get its response. This requires +sleeping, which can't be done from inside IRQ handlers. + +Platforms that support this type of GPIO distinguish them from other GPIOs by +returning nonzero from this call: + + int gpiod_cansleep(const struct gpio_desc *desc) + +To access such GPIOs, a different set of accessors is defined: + + int gpiod_get_value_cansleep(const struct gpio_desc *desc) + void gpiod_set_value_cansleep(struct gpio_desc *desc, int value) + +Accessing such GPIOs requires a context which may sleep, for example a threaded +IRQ handler, and those accessors must be used instead of spinlock-safe +accessors without the cansleep() name suffix. + +Other than the fact that these accessors might sleep, and will work on GPIOs +that can't be accessed from hardIRQ handlers, these calls act the same as the +spinlock-safe calls. + + +Active-low State and Raw GPIO Values +------------------------------------ +Device drivers like to manage the logical state of a GPIO, i.e. the value their +device will actually receive, no matter what lies between it and the GPIO line. +In some cases, it might make sense to control the actual GPIO line value. The +following set of calls ignore the active-low property of a GPIO and work on the +raw line value: + + int gpiod_get_raw_value(const struct gpio_desc *desc) + void gpiod_set_raw_value(struct gpio_desc *desc, int value) + int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc) + void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value) + +The active-low state of a GPIO can also be queried using the following call: + + int gpiod_is_active_low(const struct gpio_desc *desc) + +Note that these functions should only be used with great moderation ; a driver +should not have to care about the physical line level. + +GPIOs mapped to IRQs +-------------------- +GPIO lines can quite often be used as IRQs. You can get the IRQ number +corresponding to a given GPIO using the following call: + + int gpiod_to_irq(const struct gpio_desc *desc) + +It will return an IRQ number, or an negative errno code if the mapping can't be +done (most likely because that particular GPIO cannot be used as IRQ). It is an +unchecked error to use a GPIO that wasn't set up as an input using +gpiod_direction_input(), or to use an IRQ number that didn't originally come +from gpiod_to_irq(). gpiod_to_irq() is not allowed to sleep. + +Non-error values returned from gpiod_to_irq() can be passed to request_irq() or +free_irq(). They will often be stored into IRQ resources for platform devices, +by the board-specific initialization code. Note that IRQ trigger options are +part of the IRQ interface, e.g. IRQF_TRIGGER_FALLING, as are system wakeup +capabilities. + + +Interacting With the Legacy GPIO Subsystem +========================================== +Many kernel subsystems still handle GPIOs using the legacy integer-based +interface. Although it is strongly encouraged to upgrade them to the safer +descriptor-based API, the following two functions allow you to convert a GPIO +descriptor into the GPIO integer namespace and vice-versa: + + int desc_to_gpio(const struct gpio_desc *desc) + struct gpio_desc *gpio_to_desc(unsigned gpio) + +The GPIO number returned by desc_to_gpio() can be safely used as long as the +GPIO descriptor has not been freed. All the same, a GPIO number passed to +gpio_to_desc() must have been properly acquired, and usage of the returned GPIO +descriptor is only possible after the GPIO number has been released. + +Freeing a GPIO obtained by one API with the other API is forbidden and an +unchecked error. diff --git a/Documentation/gpio/driver.txt b/Documentation/gpio/driver.txt new file mode 100644 index 000000000000..9da0bfa74781 --- /dev/null +++ b/Documentation/gpio/driver.txt @@ -0,0 +1,75 @@ +GPIO Descriptor Driver Interface +================================ + +This document serves as a guide for GPIO chip drivers writers. Note that it +describes the new descriptor-based interface. For a description of the +deprecated integer-based GPIO interface please refer to gpio-legacy.txt. + +Each GPIO controller driver needs to include the following header, which defines +the structures used to define a GPIO driver: + + #include + + +Internal Representation of GPIOs +================================ + +Inside a GPIO driver, individual GPIOs are identified by their hardware number, +which is a unique number between 0 and n, n being the number of GPIOs managed by +the chip. This number is purely internal: the hardware number of a particular +GPIO descriptor is never made visible outside of the driver. + +On top of this internal number, each GPIO also need to have a global number in +the integer GPIO namespace so that it can be used with the legacy GPIO +interface. Each chip must thus have a "base" number (which can be automatically +assigned), and for each GPIO the global number will be (base + hardware number). +Although the integer representation is considered deprecated, it still has many +users and thus needs to be maintained. + +So for example one platform could use numbers 32-159 for GPIOs, with a +controller defining 128 GPIOs at a "base" of 32 ; while another platform uses +numbers 0..63 with one set of GPIO controllers, 64-79 with another type of GPIO +controller, and on one particular board 80-95 with an FPGA. The numbers need not +be contiguous; either of those platforms could also use numbers 2000-2063 to +identify GPIOs in a bank of I2C GPIO expanders. + + +Controller Drivers: gpio_chip +============================= + +In the gpiolib framework each GPIO controller is packaged as a "struct +gpio_chip" (see linux/gpio/driver.h for its complete definition) with members +common to each controller of that type: + + - methods to establish GPIO direction + - methods used to access GPIO values + - method to return the IRQ number associated to a given GPIO + - flag saying whether calls to its methods may sleep + - optional debugfs dump method (showing extra state like pullup config) + - optional base number (will be automatically assigned if omitted) + - label for diagnostics and GPIOs mapping using platform data + +The code implementing a gpio_chip should support multiple instances of the +controller, possibly using the driver model. That code will configure each +gpio_chip and issue gpiochip_add(). Removing a GPIO controller should be rare; +use gpiochip_remove() when it is unavoidable. + +Most often a gpio_chip is part of an instance-specific structure with state not +exposed by the GPIO interfaces, such as addressing, power management, and more. +Chips such as codecs will have complex non-GPIO state. + +Any debugfs dump method should normally ignore signals which haven't been +requested as GPIOs. They can use gpiochip_is_requested(), which returns either +NULL or the label associated with that GPIO when it was requested. + +Locking IRQ usage +----------------- +Input GPIOs can be used as IRQ signals. When this happens, a driver is requested +to mark the GPIO as being used as an IRQ: + + int gpiod_lock_as_irq(struct gpio_desc *desc) + +This will prevent the use of non-irq related GPIO APIs until the GPIO IRQ lock +is released: + + void gpiod_unlock_as_irq(struct gpio_desc *desc) diff --git a/Documentation/gpio/gpio-legacy.txt b/Documentation/gpio/gpio-legacy.txt new file mode 100644 index 000000000000..6f83fa965b4b --- /dev/null +++ b/Documentation/gpio/gpio-legacy.txt @@ -0,0 +1,775 @@ +GPIO Interfaces + +This provides an overview of GPIO access conventions on Linux. + +These calls use the gpio_* naming prefix. No other calls should use that +prefix, or the related __gpio_* prefix. + + +What is a GPIO? +=============== +A "General Purpose Input/Output" (GPIO) is a flexible software-controlled +digital signal. They are provided from many kinds of chip, and are familiar +to Linux developers working with embedded and custom hardware. Each GPIO +represents a bit connected to a particular pin, or "ball" on Ball Grid Array +(BGA) packages. Board schematics show which external hardware connects to +which GPIOs. Drivers can be written generically, so that board setup code +passes such pin configuration data to drivers. + +System-on-Chip (SOC) processors heavily rely on GPIOs. In some cases, every +non-dedicated pin can be configured as a GPIO; and most chips have at least +several dozen of them. Programmable logic devices (like FPGAs) can easily +provide GPIOs; multifunction chips like power managers, and audio codecs +often have a few such pins to help with pin scarcity on SOCs; and there are +also "GPIO Expander" chips that connect using the I2C or SPI serial busses. +Most PC southbridges have a few dozen GPIO-capable pins (with only the BIOS +firmware knowing how they're used). + +The exact capabilities of GPIOs vary between systems. Common options: + + - Output values are writable (high=1, low=0). Some chips also have + options about how that value is driven, so that for example only one + value might be driven ... supporting "wire-OR" and similar schemes + for the other value (notably, "open drain" signaling). + + - Input values are likewise readable (1, 0). Some chips support readback + of pins configured as "output", which is very useful in such "wire-OR" + cases (to support bidirectional signaling). GPIO controllers may have + input de-glitch/debounce logic, sometimes with software controls. + + - Inputs can often be used as IRQ signals, often edge triggered but + sometimes level triggered. Such IRQs may be configurable as system + wakeup events, to wake the system from a low power state. + + - Usually a GPIO will be configurable as either input or output, as needed + by different product boards; single direction ones exist too. + + - Most GPIOs can be accessed while holding spinlocks, but those accessed + through a serial bus normally can't. Some systems support both types. + +On a given board each GPIO is used for one specific purpose like monitoring +MMC/SD card insertion/removal, detecting card writeprotect status, driving +a LED, configuring a transceiver, bitbanging a serial bus, poking a hardware +watchdog, sensing a switch, and so on. + + +GPIO conventions +================ +Note that this is called a "convention" because you don't need to do it this +way, and it's no crime if you don't. There **are** cases where portability +is not the main issue; GPIOs are often used for the kind of board-specific +glue logic that may even change between board revisions, and can't ever be +used on a board that's wired differently. Only least-common-denominator +functionality can be very portable. Other features are platform-specific, +and that can be critical for glue logic. + +Plus, this doesn't require any implementation framework, just an interface. +One platform might implement it as simple inline functions accessing chip +registers; another might implement it by delegating through abstractions +used for several very different kinds of GPIO controller. (There is some +optional code supporting such an implementation strategy, described later +in this document, but drivers acting as clients to the GPIO interface must +not care how it's implemented.) + +That said, if the convention is supported on their platform, drivers should +use it when possible. Platforms must select ARCH_REQUIRE_GPIOLIB or +ARCH_WANT_OPTIONAL_GPIOLIB in their Kconfig. Drivers that can't work without +standard GPIO calls should have Kconfig entries which depend on GPIOLIB. The +GPIO calls are available, either as "real code" or as optimized-away stubs, +when drivers use the include file: + + #include + +If you stick to this convention then it'll be easier for other developers to +see what your code is doing, and help maintain it. + +Note that these operations include I/O barriers on platforms which need to +use them; drivers don't need to add them explicitly. + + +Identifying GPIOs +----------------- +GPIOs are identified by unsigned integers in the range 0..MAX_INT. That +reserves "negative" numbers for other purposes like marking signals as +"not available on this board", or indicating faults. Code that doesn't +touch the underlying hardware treats these integers as opaque cookies. + +Platforms define how they use those integers, and usually #define symbols +for the GPIO lines so that board-specific setup code directly corresponds +to the relevant schematics. In contrast, drivers should only use GPIO +numbers passed to them from that setup code, using platform_data to hold +board-specific pin configuration data (along with other board specific +data they need). That avoids portability problems. + +So for example one platform uses numbers 32-159 for GPIOs; while another +uses numbers 0..63 with one set of GPIO controllers, 64-79 with another +type of GPIO controller, and on one particular board 80-95 with an FPGA. +The numbers need not be contiguous; either of those platforms could also +use numbers 2000-2063 to identify GPIOs in a bank of I2C GPIO expanders. + +If you want to initialize a structure with an invalid GPIO number, use +some negative number (perhaps "-EINVAL"); that will never be valid. To +test if such number from such a structure could reference a GPIO, you +may use this predicate: + + int gpio_is_valid(int number); + +A number that's not valid will be rejected by calls which may request +or free GPIOs (see below). Other numbers may also be rejected; for +example, a number might be valid but temporarily unused on a given board. + +Whether a platform supports multiple GPIO controllers is a platform-specific +implementation issue, as are whether that support can leave "holes" in the space +of GPIO numbers, and whether new controllers can be added at runtime. Such issues +can affect things including whether adjacent GPIO numbers are both valid. + +Using GPIOs +----------- +The first thing a system should do with a GPIO is allocate it, using +the gpio_request() call; see later. + +One of the next things to do with a GPIO, often in board setup code when +setting up a platform_device using the GPIO, is mark its direction: + + /* set as input or output, returning 0 or negative errno */ + int gpio_direction_input(unsigned gpio); + int gpio_direction_output(unsigned gpio, int value); + +The return value is zero for success, else a negative errno. It should +be checked, since the get/set calls don't have error returns and since +misconfiguration is possible. You should normally issue these calls from +a task context. However, for spinlock-safe GPIOs it's OK to use them +before tasking is enabled, as part of early board setup. + +For output GPIOs, the value provided becomes the initial output value. +This helps avoid signal glitching during system startup. + +For compatibility with legacy interfaces to GPIOs, setting the direction +of a GPIO implicitly requests that GPIO (see below) if it has not been +requested already. That compatibility is being removed from the optional +gpiolib framework. + +Setting the direction can fail if the GPIO number is invalid, or when +that particular GPIO can't be used in that mode. It's generally a bad +idea to rely on boot firmware to have set the direction correctly, since +it probably wasn't validated to do more than boot Linux. (Similarly, +that board setup code probably needs to multiplex that pin as a GPIO, +and configure pullups/pulldowns appropriately.) + + +Spinlock-Safe GPIO access +------------------------- +Most GPIO controllers can be accessed with memory read/write instructions. +Those don't need to sleep, and can safely be done from inside hard +(nonthreaded) IRQ handlers and similar contexts. + +Use the following calls to access such GPIOs, +for which gpio_cansleep() will always return false (see below): + + /* GPIO INPUT: return zero or nonzero */ + int gpio_get_value(unsigned gpio); + + /* GPIO OUTPUT */ + void gpio_set_value(unsigned gpio, int value); + +The values are boolean, zero for low, nonzero for high. When reading the +value of an output pin, the value returned should be what's seen on the +pin ... that won't always match the specified output value, because of +issues including open-drain signaling and output latencies. + +The get/set calls have no error returns because "invalid GPIO" should have +been reported earlier from gpio_direction_*(). However, note that not all +platforms can read the value of output pins; those that can't should always +return zero. Also, using these calls for GPIOs that can't safely be accessed +without sleeping (see below) is an error. + +Platform-specific implementations are encouraged to optimize the two +calls to access the GPIO value in cases where the GPIO number (and for +output, value) are constant. It's normal for them to need only a couple +of instructions in such cases (reading or writing a hardware register), +and not to need spinlocks. Such optimized calls can make bitbanging +applications a lot more efficient (in both space and time) than spending +dozens of instructions on subroutine calls. + + +GPIO access that may sleep +-------------------------- +Some GPIO controllers must be accessed using message based busses like I2C +or SPI. Commands to read or write those GPIO values require waiting to +get to the head of a queue to transmit a command and get its response. +This requires sleeping, which can't be done from inside IRQ handlers. + +Platforms that support this type of GPIO distinguish them from other GPIOs +by returning nonzero from this call (which requires a valid GPIO number, +which should have been previously allocated with gpio_request): + + int gpio_cansleep(unsigned gpio); + +To access such GPIOs, a different set of accessors is defined: + + /* GPIO INPUT: return zero or nonzero, might sleep */ + int gpio_get_value_cansleep(unsigned gpio); + + /* GPIO OUTPUT, might sleep */ + void gpio_set_value_cansleep(unsigned gpio, int value); + + +Accessing such GPIOs requires a context which may sleep, for example +a threaded IRQ handler, and those accessors must be used instead of +spinlock-safe accessors without the cansleep() name suffix. + +Other than the fact that these accessors might sleep, and will work +on GPIOs that can't be accessed from hardIRQ handlers, these calls act +the same as the spinlock-safe calls. + + ** IN ADDITION ** calls to setup and configure such GPIOs must be made +from contexts which may sleep, since they may need to access the GPIO +controller chip too: (These setup calls are usually made from board +setup or driver probe/teardown code, so this is an easy constraint.) + + gpio_direction_input() + gpio_direction_output() + gpio_request() + +## gpio_request_one() +## gpio_request_array() +## gpio_free_array() + + gpio_free() + gpio_set_debounce() + + + +Claiming and Releasing GPIOs +---------------------------- +To help catch system configuration errors, two calls are defined. + + /* request GPIO, returning 0 or negative errno. + * non-null labels may be useful for diagnostics. + */ + int gpio_request(unsigned gpio, const char *label); + + /* release previously-claimed GPIO */ + void gpio_free(unsigned gpio); + +Passing invalid GPIO numbers to gpio_request() will fail, as will requesting +GPIOs that have already been claimed with that call. The return value of +gpio_request() must be checked. You should normally issue these calls from +a task context. However, for spinlock-safe GPIOs it's OK to request GPIOs +before tasking is enabled, as part of early board setup. + +These calls serve two basic purposes. One is marking the signals which +are actually in use as GPIOs, for better diagnostics; systems may have +several hundred potential GPIOs, but often only a dozen are used on any +given board. Another is to catch conflicts, identifying errors when +(a) two or more drivers wrongly think they have exclusive use of that +signal, or (b) something wrongly believes it's safe to remove drivers +needed to manage a signal that's in active use. That is, requesting a +GPIO can serve as a kind of lock. + +Some platforms may also use knowledge about what GPIOs are active for +power management, such as by powering down unused chip sectors and, more +easily, gating off unused clocks. + +For GPIOs that use pins known to the pinctrl subsystem, that subsystem should +be informed of their use; a gpiolib driver's .request() operation may call +pinctrl_request_gpio(), and a gpiolib driver's .free() operation may call +pinctrl_free_gpio(). The pinctrl subsystem allows a pinctrl_request_gpio() +to succeed concurrently with a pin or pingroup being "owned" by a device for +pin multiplexing. + +Any programming of pin multiplexing hardware that is needed to route the +GPIO signal to the appropriate pin should occur within a GPIO driver's +.direction_input() or .direction_output() operations, and occur after any +setup of an output GPIO's value. This allows a glitch-free migration from a +pin's special function to GPIO. This is sometimes required when using a GPIO +to implement a workaround on signals typically driven by a non-GPIO HW block. + +Some platforms allow some or all GPIO signals to be routed to different pins. +Similarly, other aspects of the GPIO or pin may need to be configured, such as +pullup/pulldown. Platform software should arrange that any such details are +configured prior to gpio_request() being called for those GPIOs, e.g. using +the pinctrl subsystem's mapping table, so that GPIO users need not be aware +of these details. + +Also note that it's your responsibility to have stopped using a GPIO +before you free it. + +Considering in most cases GPIOs are actually configured right after they +are claimed, three additional calls are defined: + + /* request a single GPIO, with initial configuration specified by + * 'flags', identical to gpio_request() wrt other arguments and + * return value + */ + int gpio_request_one(unsigned gpio, unsigned long flags, const char *label); + + /* request multiple GPIOs in a single call + */ + int gpio_request_array(struct gpio *array, size_t num); + + /* release multiple GPIOs in a single call + */ + void gpio_free_array(struct gpio *array, size_t num); + +where 'flags' is currently defined to specify the following properties: + + * GPIOF_DIR_IN - to configure direction as input + * GPIOF_DIR_OUT - to configure direction as output + + * GPIOF_INIT_LOW - as output, set initial level to LOW + * GPIOF_INIT_HIGH - as output, set initial level to HIGH + * GPIOF_OPEN_DRAIN - gpio pin is open drain type. + * GPIOF_OPEN_SOURCE - gpio pin is open source type. + + * GPIOF_EXPORT_DIR_FIXED - export gpio to sysfs, keep direction + * GPIOF_EXPORT_DIR_CHANGEABLE - also export, allow changing direction + +since GPIOF_INIT_* are only valid when configured as output, so group valid +combinations as: + + * GPIOF_IN - configure as input + * GPIOF_OUT_INIT_LOW - configured as output, initial level LOW + * GPIOF_OUT_INIT_HIGH - configured as output, initial level HIGH + +When setting the flag as GPIOF_OPEN_DRAIN then it will assume that pins is +open drain type. Such pins will not be driven to 1 in output mode. It is +require to connect pull-up on such pins. By enabling this flag, gpio lib will +make the direction to input when it is asked to set value of 1 in output mode +to make the pin HIGH. The pin is make to LOW by driving value 0 in output mode. + +When setting the flag as GPIOF_OPEN_SOURCE then it will assume that pins is +open source type. Such pins will not be driven to 0 in output mode. It is +require to connect pull-down on such pin. By enabling this flag, gpio lib will +make the direction to input when it is asked to set value of 0 in output mode +to make the pin LOW. The pin is make to HIGH by driving value 1 in output mode. + +In the future, these flags can be extended to support more properties. + +Further more, to ease the claim/release of multiple GPIOs, 'struct gpio' is +introduced to encapsulate all three fields as: + + struct gpio { + unsigned gpio; + unsigned long flags; + const char *label; + }; + +A typical example of usage: + + static struct gpio leds_gpios[] = { + { 32, GPIOF_OUT_INIT_HIGH, "Power LED" }, /* default to ON */ + { 33, GPIOF_OUT_INIT_LOW, "Green LED" }, /* default to OFF */ + { 34, GPIOF_OUT_INIT_LOW, "Red LED" }, /* default to OFF */ + { 35, GPIOF_OUT_INIT_LOW, "Blue LED" }, /* default to OFF */ + { ... }, + }; + + err = gpio_request_one(31, GPIOF_IN, "Reset Button"); + if (err) + ... + + err = gpio_request_array(leds_gpios, ARRAY_SIZE(leds_gpios)); + if (err) + ... + + gpio_free_array(leds_gpios, ARRAY_SIZE(leds_gpios)); + + +GPIOs mapped to IRQs +-------------------- +GPIO numbers are unsigned integers; so are IRQ numbers. These make up +two logically distinct namespaces (GPIO 0 need not use IRQ 0). You can +map between them using calls like: + + /* map GPIO numbers to IRQ numbers */ + int gpio_to_irq(unsigned gpio); + + /* map IRQ numbers to GPIO numbers (avoid using this) */ + int irq_to_gpio(unsigned irq); + +Those return either the corresponding number in the other namespace, or +else a negative errno code if the mapping can't be done. (For example, +some GPIOs can't be used as IRQs.) It is an unchecked error to use a GPIO +number that wasn't set up as an input using gpio_direction_input(), or +to use an IRQ number that didn't originally come from gpio_to_irq(). + +These two mapping calls are expected to cost on the order of a single +addition or subtraction. They're not allowed to sleep. + +Non-error values returned from gpio_to_irq() can be passed to request_irq() +or free_irq(). They will often be stored into IRQ resources for platform +devices, by the board-specific initialization code. Note that IRQ trigger +options are part of the IRQ interface, e.g. IRQF_TRIGGER_FALLING, as are +system wakeup capabilities. + +Non-error values returned from irq_to_gpio() would most commonly be used +with gpio_get_value(), for example to initialize or update driver state +when the IRQ is edge-triggered. Note that some platforms don't support +this reverse mapping, so you should avoid using it. + + +Emulating Open Drain Signals +---------------------------- +Sometimes shared signals need to use "open drain" signaling, where only the +low signal level is actually driven. (That term applies to CMOS transistors; +"open collector" is used for TTL.) A pullup resistor causes the high signal +level. This is sometimes called a "wire-AND"; or more practically, from the +negative logic (low=true) perspective this is a "wire-OR". + +One common example of an open drain signal is a shared active-low IRQ line. +Also, bidirectional data bus signals sometimes use open drain signals. + +Some GPIO controllers directly support open drain outputs; many don't. When +you need open drain signaling but your hardware doesn't directly support it, +there's a common idiom you can use to emulate it with any GPIO pin that can +be used as either an input or an output: + + LOW: gpio_direction_output(gpio, 0) ... this drives the signal + and overrides the pullup. + + HIGH: gpio_direction_input(gpio) ... this turns off the output, + so the pullup (or some other device) controls the signal. + +If you are "driving" the signal high but gpio_get_value(gpio) reports a low +value (after the appropriate rise time passes), you know some other component +is driving the shared signal low. That's not necessarily an error. As one +common example, that's how I2C clocks are stretched: a slave that needs a +slower clock delays the rising edge of SCK, and the I2C master adjusts its +signaling rate accordingly. + + +GPIO controllers and the pinctrl subsystem +------------------------------------------ + +A GPIO controller on a SOC might be tightly coupled with the pinctrl +subsystem, in the sense that the pins can be used by other functions +together with an optional gpio feature. We have already covered the +case where e.g. a GPIO controller need to reserve a pin or set the +direction of a pin by calling any of: + +pinctrl_request_gpio() +pinctrl_free_gpio() +pinctrl_gpio_direction_input() +pinctrl_gpio_direction_output() + +But how does the pin control subsystem cross-correlate the GPIO +numbers (which are a global business) to a certain pin on a certain +pin controller? + +This is done by registering "ranges" of pins, which are essentially +cross-reference tables. These are described in +Documentation/pinctrl.txt + +While the pin allocation is totally managed by the pinctrl subsystem, +gpio (under gpiolib) is still maintained by gpio drivers. It may happen +that different pin ranges in a SoC is managed by different gpio drivers. + +This makes it logical to let gpio drivers announce their pin ranges to +the pin ctrl subsystem before it will call 'pinctrl_request_gpio' in order +to request the corresponding pin to be prepared by the pinctrl subsystem +before any gpio usage. + +For this, the gpio controller can register its pin range with pinctrl +subsystem. There are two ways of doing it currently: with or without DT. + +For with DT support refer to Documentation/devicetree/bindings/gpio/gpio.txt. + +For non-DT support, user can call gpiochip_add_pin_range() with appropriate +parameters to register a range of gpio pins with a pinctrl driver. For this +exact name string of pinctrl device has to be passed as one of the +argument to this routine. + + +What do these conventions omit? +=============================== +One of the biggest things these conventions omit is pin multiplexing, since +this is highly chip-specific and nonportable. One platform might not need +explicit multiplexing; another might have just two options for use of any +given pin; another might have eight options per pin; another might be able +to route a given GPIO to any one of several pins. (Yes, those examples all +come from systems that run Linux today.) + +Related to multiplexing is configuration and enabling of the pullups or +pulldowns integrated on some platforms. Not all platforms support them, +or support them in the same way; and any given board might use external +pullups (or pulldowns) so that the on-chip ones should not be used. +(When a circuit needs 5 kOhm, on-chip 100 kOhm resistors won't do.) +Likewise drive strength (2 mA vs 20 mA) and voltage (1.8V vs 3.3V) is a +platform-specific issue, as are models like (not) having a one-to-one +correspondence between configurable pins and GPIOs. + +There are other system-specific mechanisms that are not specified here, +like the aforementioned options for input de-glitching and wire-OR output. +Hardware may support reading or writing GPIOs in gangs, but that's usually +configuration dependent: for GPIOs sharing the same bank. (GPIOs are +commonly grouped in banks of 16 or 32, with a given SOC having several such +banks.) Some systems can trigger IRQs from output GPIOs, or read values +from pins not managed as GPIOs. Code relying on such mechanisms will +necessarily be nonportable. + +Dynamic definition of GPIOs is not currently standard; for example, as +a side effect of configuring an add-on board with some GPIO expanders. + + +GPIO implementor's framework (OPTIONAL) +======================================= +As noted earlier, there is an optional implementation framework making it +easier for platforms to support different kinds of GPIO controller using +the same programming interface. This framework is called "gpiolib". + +As a debugging aid, if debugfs is available a /sys/kernel/debug/gpio file +will be found there. That will list all the controllers registered through +this framework, and the state of the GPIOs currently in use. + + +Controller Drivers: gpio_chip +----------------------------- +In this framework each GPIO controller is packaged as a "struct gpio_chip" +with information common to each controller of that type: + + - methods to establish GPIO direction + - methods used to access GPIO values + - flag saying whether calls to its methods may sleep + - optional debugfs dump method (showing extra state like pullup config) + - label for diagnostics + +There is also per-instance data, which may come from device.platform_data: +the number of its first GPIO, and how many GPIOs it exposes. + +The code implementing a gpio_chip should support multiple instances of the +controller, possibly using the driver model. That code will configure each +gpio_chip and issue gpiochip_add(). Removing a GPIO controller should be +rare; use gpiochip_remove() when it is unavoidable. + +Most often a gpio_chip is part of an instance-specific structure with state +not exposed by the GPIO interfaces, such as addressing, power management, +and more. Chips such as codecs will have complex non-GPIO state. + +Any debugfs dump method should normally ignore signals which haven't been +requested as GPIOs. They can use gpiochip_is_requested(), which returns +either NULL or the label associated with that GPIO when it was requested. + + +Platform Support +---------------- +To support this framework, a platform's Kconfig will "select" either +ARCH_REQUIRE_GPIOLIB or ARCH_WANT_OPTIONAL_GPIOLIB +and arrange that its includes and defines +three functions: gpio_get_value(), gpio_set_value(), and gpio_cansleep(). + +It may also provide a custom value for ARCH_NR_GPIOS, so that it better +reflects the number of GPIOs in actual use on that platform, without +wasting static table space. (It should count both built-in/SoC GPIOs and +also ones on GPIO expanders. + +ARCH_REQUIRE_GPIOLIB means that the gpiolib code will always get compiled +into the kernel on that architecture. + +ARCH_WANT_OPTIONAL_GPIOLIB means the gpiolib code defaults to off and the user +can enable it and build it into the kernel optionally. + +If neither of these options are selected, the platform does not support +GPIOs through GPIO-lib and the code cannot be enabled by the user. + +Trivial implementations of those functions can directly use framework +code, which always dispatches through the gpio_chip: + + #define gpio_get_value __gpio_get_value + #define gpio_set_value __gpio_set_value + #define gpio_cansleep __gpio_cansleep + +Fancier implementations could instead define those as inline functions with +logic optimizing access to specific SOC-based GPIOs. For example, if the +referenced GPIO is the constant "12", getting or setting its value could +cost as little as two or three instructions, never sleeping. When such an +optimization is not possible those calls must delegate to the framework +code, costing at least a few dozen instructions. For bitbanged I/O, such +instruction savings can be significant. + +For SOCs, platform-specific code defines and registers gpio_chip instances +for each bank of on-chip GPIOs. Those GPIOs should be numbered/labeled to +match chip vendor documentation, and directly match board schematics. They +may well start at zero and go up to a platform-specific limit. Such GPIOs +are normally integrated into platform initialization to make them always be +available, from arch_initcall() or earlier; they can often serve as IRQs. + + +Board Support +------------- +For external GPIO controllers -- such as I2C or SPI expanders, ASICs, multi +function devices, FPGAs or CPLDs -- most often board-specific code handles +registering controller devices and ensures that their drivers know what GPIO +numbers to use with gpiochip_add(). Their numbers often start right after +platform-specific GPIOs. + +For example, board setup code could create structures identifying the range +of GPIOs that chip will expose, and passes them to each GPIO expander chip +using platform_data. Then the chip driver's probe() routine could pass that +data to gpiochip_add(). + +Initialization order can be important. For example, when a device relies on +an I2C-based GPIO, its probe() routine should only be called after that GPIO +becomes available. That may mean the device should not be registered until +calls for that GPIO can work. One way to address such dependencies is for +such gpio_chip controllers to provide setup() and teardown() callbacks to +board specific code; those board specific callbacks would register devices +once all the necessary resources are available, and remove them later when +the GPIO controller device becomes unavailable. + + +Sysfs Interface for Userspace (OPTIONAL) +======================================== +Platforms which use the "gpiolib" implementors framework may choose to +configure a sysfs user interface to GPIOs. This is different from the +debugfs interface, since it provides control over GPIO direction and +value instead of just showing a gpio state summary. Plus, it could be +present on production systems without debugging support. + +Given appropriate hardware documentation for the system, userspace could +know for example that GPIO #23 controls the write protect line used to +protect boot loader segments in flash memory. System upgrade procedures +may need to temporarily remove that protection, first importing a GPIO, +then changing its output state, then updating the code before re-enabling +the write protection. In normal use, GPIO #23 would never be touched, +and the kernel would have no need to know about it. + +Again depending on appropriate hardware documentation, on some systems +userspace GPIO can be used to determine system configuration data that +standard kernels won't know about. And for some tasks, simple userspace +GPIO drivers could be all that the system really needs. + +Note that standard kernel drivers exist for common "LEDs and Buttons" +GPIO tasks: "leds-gpio" and "gpio_keys", respectively. Use those +instead of talking directly to the GPIOs; they integrate with kernel +frameworks better than your userspace code could. + + +Paths in Sysfs +-------------- +There are three kinds of entry in /sys/class/gpio: + + - Control interfaces used to get userspace control over GPIOs; + + - GPIOs themselves; and + + - GPIO controllers ("gpio_chip" instances). + +That's in addition to standard files including the "device" symlink. + +The control interfaces are write-only: + + /sys/class/gpio/ + + "export" ... Userspace may ask the kernel to export control of + a GPIO to userspace by writing its number to this file. + + Example: "echo 19 > export" will create a "gpio19" node + for GPIO #19, if that's not requested by kernel code. + + "unexport" ... Reverses the effect of exporting to userspace. + + Example: "echo 19 > unexport" will remove a "gpio19" + node exported using the "export" file. + +GPIO signals have paths like /sys/class/gpio/gpio42/ (for GPIO #42) +and have the following read/write attributes: + + /sys/class/gpio/gpioN/ + + "direction" ... reads as either "in" or "out". This value may + normally be written. Writing as "out" defaults to + initializing the value as low. To ensure glitch free + operation, values "low" and "high" may be written to + configure the GPIO as an output with that initial value. + + Note that this attribute *will not exist* if the kernel + doesn't support changing the direction of a GPIO, or + it was exported by kernel code that didn't explicitly + allow userspace to reconfigure this GPIO's direction. + + "value" ... reads as either 0 (low) or 1 (high). If the GPIO + is configured as an output, this value may be written; + any nonzero value is treated as high. + + If the pin can be configured as interrupt-generating interrupt + and if it has been configured to generate interrupts (see the + description of "edge"), you can poll(2) on that file and + poll(2) will return whenever the interrupt was triggered. If + you use poll(2), set the events POLLPRI and POLLERR. If you + use select(2), set the file descriptor in exceptfds. After + poll(2) returns, either lseek(2) to the beginning of the sysfs + file and read the new value or close the file and re-open it + to read the value. + + "edge" ... reads as either "none", "rising", "falling", or + "both". Write these strings to select the signal edge(s) + that will make poll(2) on the "value" file return. + + This file exists only if the pin can be configured as an + interrupt generating input pin. + + "active_low" ... reads as either 0 (false) or 1 (true). Write + any nonzero value to invert the value attribute both + for reading and writing. Existing and subsequent + poll(2) support configuration via the edge attribute + for "rising" and "falling" edges will follow this + setting. + +GPIO controllers have paths like /sys/class/gpio/gpiochip42/ (for the +controller implementing GPIOs starting at #42) and have the following +read-only attributes: + + /sys/class/gpio/gpiochipN/ + + "base" ... same as N, the first GPIO managed by this chip + + "label" ... provided for diagnostics (not always unique) + + "ngpio" ... how many GPIOs this manges (N to N + ngpio - 1) + +Board documentation should in most cases cover what GPIOs are used for +what purposes. However, those numbers are not always stable; GPIOs on +a daughtercard might be different depending on the base board being used, +or other cards in the stack. In such cases, you may need to use the +gpiochip nodes (possibly in conjunction with schematics) to determine +the correct GPIO number to use for a given signal. + + +Exporting from Kernel code +-------------------------- +Kernel code can explicitly manage exports of GPIOs which have already been +requested using gpio_request(): + + /* export the GPIO to userspace */ + int gpio_export(unsigned gpio, bool direction_may_change); + + /* reverse gpio_export() */ + void gpio_unexport(); + + /* create a sysfs link to an exported GPIO node */ + int gpio_export_link(struct device *dev, const char *name, + unsigned gpio) + + /* change the polarity of a GPIO node in sysfs */ + int gpio_sysfs_set_active_low(unsigned gpio, int value); + +After a kernel driver requests a GPIO, it may only be made available in +the sysfs interface by gpio_export(). The driver can control whether the +signal direction may change. This helps drivers prevent userspace code +from accidentally clobbering important system state. + +This explicit exporting can help with debugging (by making some kinds +of experiments easier), or can provide an always-there interface that's +suitable for documenting as part of a board support package. + +After the GPIO has been exported, gpio_export_link() allows creating +symlinks from elsewhere in sysfs to the GPIO sysfs node. Drivers can +use this to provide the interface under their own device in sysfs with +a descriptive name. + +Drivers can use gpio_sysfs_set_active_low() to hide GPIO line polarity +differences between boards from user space. This only affects the +sysfs interface. Polarity change can be done both before and after +gpio_export(), and previously enabled poll(2) support for either +rising or falling edge will be reconfigured to follow this setting. diff --git a/Documentation/gpio/gpio.txt b/Documentation/gpio/gpio.txt new file mode 100644 index 000000000000..cd9b356e88cd --- /dev/null +++ b/Documentation/gpio/gpio.txt @@ -0,0 +1,119 @@ +GPIO Interfaces +=============== + +The documents in this directory give detailed instructions on how to access +GPIOs in drivers, and how to write a driver for a device that provides GPIOs +itself. + +Due to the history of GPIO interfaces in the kernel, there are two different +ways to obtain and use GPIOs: + + - The descriptor-based interface is the preferred way to manipulate GPIOs, +and is described by all the files in this directory excepted gpio-legacy.txt. + - The legacy integer-based interface which is considered deprecated (but still +usable for compatibility reasons) is documented in gpio-legacy.txt. + +The remainder of this document applies to the new descriptor-based interface. +gpio-legacy.txt contains the same information applied to the legacy +integer-based interface. + + +What is a GPIO? +=============== + +A "General Purpose Input/Output" (GPIO) is a flexible software-controlled +digital signal. They are provided from many kinds of chip, and are familiar +to Linux developers working with embedded and custom hardware. Each GPIO +represents a bit connected to a particular pin, or "ball" on Ball Grid Array +(BGA) packages. Board schematics show which external hardware connects to +which GPIOs. Drivers can be written generically, so that board setup code +passes such pin configuration data to drivers. + +System-on-Chip (SOC) processors heavily rely on GPIOs. In some cases, every +non-dedicated pin can be configured as a GPIO; and most chips have at least +several dozen of them. Programmable logic devices (like FPGAs) can easily +provide GPIOs; multifunction chips like power managers, and audio codecs +often have a few such pins to help with pin scarcity on SOCs; and there are +also "GPIO Expander" chips that connect using the I2C or SPI serial buses. +Most PC southbridges have a few dozen GPIO-capable pins (with only the BIOS +firmware knowing how they're used). + +The exact capabilities of GPIOs vary between systems. Common options: + + - Output values are writable (high=1, low=0). Some chips also have + options about how that value is driven, so that for example only one + value might be driven, supporting "wire-OR" and similar schemes for the + other value (notably, "open drain" signaling). + + - Input values are likewise readable (1, 0). Some chips support readback + of pins configured as "output", which is very useful in such "wire-OR" + cases (to support bidirectional signaling). GPIO controllers may have + input de-glitch/debounce logic, sometimes with software controls. + + - Inputs can often be used as IRQ signals, often edge triggered but + sometimes level triggered. Such IRQs may be configurable as system + wakeup events, to wake the system from a low power state. + + - Usually a GPIO will be configurable as either input or output, as needed + by different product boards; single direction ones exist too. + + - Most GPIOs can be accessed while holding spinlocks, but those accessed + through a serial bus normally can't. Some systems support both types. + +On a given board each GPIO is used for one specific purpose like monitoring +MMC/SD card insertion/removal, detecting card write-protect status, driving +a LED, configuring a transceiver, bit-banging a serial bus, poking a hardware +watchdog, sensing a switch, and so on. + + +Common GPIO Properties +====================== + +These properties are met through all the other documents of the GPIO interface +and it is useful to understand them, especially if you need to define GPIO +mappings. + +Active-High and Active-Low +-------------------------- +It is natural to assume that a GPIO is "active" when its output signal is 1 +("high"), and inactive when it is 0 ("low"). However in practice the signal of a +GPIO may be inverted before is reaches its destination, or a device could decide +to have different conventions about what "active" means. Such decisions should +be transparent to device drivers, therefore it is possible to define a GPIO as +being either active-high ("1" means "active", the default) or active-low ("0" +means "active") so that drivers only need to worry about the logical signal and +not about what happens at the line level. + +Open Drain and Open Source +-------------------------- +Sometimes shared signals need to use "open drain" (where only the low signal +level is actually driven), or "open source" (where only the high signal level is +driven) signaling. That term applies to CMOS transistors; "open collector" is +used for TTL. A pullup or pulldown resistor causes the high or low signal level. +This is sometimes called a "wire-AND"; or more practically, from the negative +logic (low=true) perspective this is a "wire-OR". + +One common example of an open drain signal is a shared active-low IRQ line. +Also, bidirectional data bus signals sometimes use open drain signals. + +Some GPIO controllers directly support open drain and open source outputs; many +don't. When you need open drain signaling but your hardware doesn't directly +support it, there's a common idiom you can use to emulate it with any GPIO pin +that can be used as either an input or an output: + + LOW: gpiod_direction_output(gpio, 0) ... this drives the signal and overrides + the pullup. + + HIGH: gpiod_direction_input(gpio) ... this turns off the output, so the pullup + (or some other device) controls the signal. + +The same logic can be applied to emulate open source signaling, by driving the +high signal and configuring the GPIO as input for low. This open drain/open +source emulation can be handled transparently by the GPIO framework. + +If you are "driving" the signal high but gpiod_get_value(gpio) reports a low +value (after the appropriate rise time passes), you know some other component is +driving the shared signal low. That's not necessarily an error. As one common +example, that's how I2C clocks are stretched: a slave that needs a slower clock +delays the rising edge of SCK, and the I2C master adjusts its signaling rate +accordingly. diff --git a/Documentation/gpio/sysfs.txt b/Documentation/gpio/sysfs.txt new file mode 100644 index 000000000000..c2c3a97f8ff7 --- /dev/null +++ b/Documentation/gpio/sysfs.txt @@ -0,0 +1,155 @@ +GPIO Sysfs Interface for Userspace +================================== + +Platforms which use the "gpiolib" implementors framework may choose to +configure a sysfs user interface to GPIOs. This is different from the +debugfs interface, since it provides control over GPIO direction and +value instead of just showing a gpio state summary. Plus, it could be +present on production systems without debugging support. + +Given appropriate hardware documentation for the system, userspace could +know for example that GPIO #23 controls the write protect line used to +protect boot loader segments in flash memory. System upgrade procedures +may need to temporarily remove that protection, first importing a GPIO, +then changing its output state, then updating the code before re-enabling +the write protection. In normal use, GPIO #23 would never be touched, +and the kernel would have no need to know about it. + +Again depending on appropriate hardware documentation, on some systems +userspace GPIO can be used to determine system configuration data that +standard kernels won't know about. And for some tasks, simple userspace +GPIO drivers could be all that the system really needs. + +Note that standard kernel drivers exist for common "LEDs and Buttons" +GPIO tasks: "leds-gpio" and "gpio_keys", respectively. Use those +instead of talking directly to the GPIOs; they integrate with kernel +frameworks better than your userspace code could. + + +Paths in Sysfs +-------------- +There are three kinds of entry in /sys/class/gpio: + + - Control interfaces used to get userspace control over GPIOs; + + - GPIOs themselves; and + + - GPIO controllers ("gpio_chip" instances). + +That's in addition to standard files including the "device" symlink. + +The control interfaces are write-only: + + /sys/class/gpio/ + + "export" ... Userspace may ask the kernel to export control of + a GPIO to userspace by writing its number to this file. + + Example: "echo 19 > export" will create a "gpio19" node + for GPIO #19, if that's not requested by kernel code. + + "unexport" ... Reverses the effect of exporting to userspace. + + Example: "echo 19 > unexport" will remove a "gpio19" + node exported using the "export" file. + +GPIO signals have paths like /sys/class/gpio/gpio42/ (for GPIO #42) +and have the following read/write attributes: + + /sys/class/gpio/gpioN/ + + "direction" ... reads as either "in" or "out". This value may + normally be written. Writing as "out" defaults to + initializing the value as low. To ensure glitch free + operation, values "low" and "high" may be written to + configure the GPIO as an output with that initial value. + + Note that this attribute *will not exist* if the kernel + doesn't support changing the direction of a GPIO, or + it was exported by kernel code that didn't explicitly + allow userspace to reconfigure this GPIO's direction. + + "value" ... reads as either 0 (low) or 1 (high). If the GPIO + is configured as an output, this value may be written; + any nonzero value is treated as high. + + If the pin can be configured as interrupt-generating interrupt + and if it has been configured to generate interrupts (see the + description of "edge"), you can poll(2) on that file and + poll(2) will return whenever the interrupt was triggered. If + you use poll(2), set the events POLLPRI and POLLERR. If you + use select(2), set the file descriptor in exceptfds. After + poll(2) returns, either lseek(2) to the beginning of the sysfs + file and read the new value or close the file and re-open it + to read the value. + + "edge" ... reads as either "none", "rising", "falling", or + "both". Write these strings to select the signal edge(s) + that will make poll(2) on the "value" file return. + + This file exists only if the pin can be configured as an + interrupt generating input pin. + + "active_low" ... reads as either 0 (false) or 1 (true). Write + any nonzero value to invert the value attribute both + for reading and writing. Existing and subsequent + poll(2) support configuration via the edge attribute + for "rising" and "falling" edges will follow this + setting. + +GPIO controllers have paths like /sys/class/gpio/gpiochip42/ (for the +controller implementing GPIOs starting at #42) and have the following +read-only attributes: + + /sys/class/gpio/gpiochipN/ + + "base" ... same as N, the first GPIO managed by this chip + + "label" ... provided for diagnostics (not always unique) + + "ngpio" ... how many GPIOs this manges (N to N + ngpio - 1) + +Board documentation should in most cases cover what GPIOs are used for +what purposes. However, those numbers are not always stable; GPIOs on +a daughtercard might be different depending on the base board being used, +or other cards in the stack. In such cases, you may need to use the +gpiochip nodes (possibly in conjunction with schematics) to determine +the correct GPIO number to use for a given signal. + + +Exporting from Kernel code +-------------------------- +Kernel code can explicitly manage exports of GPIOs which have already been +requested using gpio_request(): + + /* export the GPIO to userspace */ + int gpiod_export(struct gpio_desc *desc, bool direction_may_change); + + /* reverse gpio_export() */ + void gpiod_unexport(struct gpio_desc *desc); + + /* create a sysfs link to an exported GPIO node */ + int gpiod_export_link(struct device *dev, const char *name, + struct gpio_desc *desc); + + /* change the polarity of a GPIO node in sysfs */ + int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value); + +After a kernel driver requests a GPIO, it may only be made available in +the sysfs interface by gpiod_export(). The driver can control whether the +signal direction may change. This helps drivers prevent userspace code +from accidentally clobbering important system state. + +This explicit exporting can help with debugging (by making some kinds +of experiments easier), or can provide an always-there interface that's +suitable for documenting as part of a board support package. + +After the GPIO has been exported, gpiod_export_link() allows creating +symlinks from elsewhere in sysfs to the GPIO sysfs node. Drivers can +use this to provide the interface under their own device in sysfs with +a descriptive name. + +Drivers can use gpiod_sysfs_set_active_low() to hide GPIO line polarity +differences between boards from user space. Polarity change can be done both +before and after gpiod_export(), and previously enabled poll(2) support for +either rising or falling edge will be reconfigured to follow this setting. -- cgit v1.2.3 From 9cb238c00ba5c1ddfff2c2ed6aa66c15b962e4c3 Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Tue, 26 Nov 2013 15:50:33 -0800 Subject: mmc: omap: Fix I2C dependency and make driver usable with device tree Some features can be configured by the companion I2C chips, which may not be available at the probe time. Fix the issue by returning -EPROBE_DEFER when the MMC controller slots are not configured. While at it, let's also add minimal device tree support so omap24xx platforms can use this driver without legacy mode since we claim to support device tree for mach-omap2 based systems. Although adding the minimal device tree support is not strictly a fix, it does remove one of the last blockers for dropping a bunch of legacy platform data for mach-omap2. Cc: linux-mmc@vger.kernel.org Acked-by: Chris Ball Signed-off-by: Tony Lindgren --- Documentation/devicetree/bindings/mmc/ti-omap.txt | 54 +++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 Documentation/devicetree/bindings/mmc/ti-omap.txt (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/mmc/ti-omap.txt b/Documentation/devicetree/bindings/mmc/ti-omap.txt new file mode 100644 index 000000000000..8de579969763 --- /dev/null +++ b/Documentation/devicetree/bindings/mmc/ti-omap.txt @@ -0,0 +1,54 @@ +* TI MMC host controller for OMAP1 and 2420 + +The MMC Host Controller on TI OMAP1 and 2420 family provides +an interface for MMC, SD, and SDIO types of memory cards. + +This file documents differences between the core properties described +by mmc.txt and the properties used by the omap mmc driver. + +Note that this driver will not work with omap2430 or later omaps, +please see the omap hsmmc driver for the current omaps. + +Required properties: +- compatible: Must be "ti,omap2420-mmc", for OMAP2420 controllers +- ti,hwmods: For 2420, must be "msdi", where n is controller + instance starting 1 + +Examples: + + msdi1: mmc@4809c000 { + compatible = "ti,omap2420-mmc"; + ti,hwmods = "msdi1"; + reg = <0x4809c000 0x80>; + interrupts = <83>; + dmas = <&sdma 61 &sdma 62>; + dma-names = "tx", "rx"; + }; + +* TI MMC host controller for OMAP1 and 2420 + +The MMC Host Controller on TI OMAP1 and 2420 family provides +an interface for MMC, SD, and SDIO types of memory cards. + +This file documents differences between the core properties described +by mmc.txt and the properties used by the omap mmc driver. + +Note that this driver will not work with omap2430 or later omaps, +please see the omap hsmmc driver for the current omaps. + +Required properties: +- compatible: Must be "ti,omap2420-mmc", for OMAP2420 controllers +- ti,hwmods: For 2420, must be "msdi", where n is controller + instance starting 1 + +Examples: + + msdi1: mmc@4809c000 { + compatible = "ti,omap2420-mmc"; + ti,hwmods = "msdi1"; + reg = <0x4809c000 0x80>; + interrupts = <83>; + dmas = <&sdma 61 &sdma 62>; + dma-names = "tx", "rx"; + }; + -- cgit v1.2.3 From 286c24028c7f2df637323e672d9aa54a07b67bde Mon Sep 17 00:00:00 2001 From: Ashutosh Dixit Date: Wed, 27 Nov 2013 08:58:40 -0800 Subject: misc: mic: Bug fix for sysfs poll usage. MIC user space daemon poll's on sysfs changes. The documentation for sysfs_poll(...) in fs/sysfs/file.c states that "Once poll/select indicates that the value has changed, you need to close and re-open the file, or seek to 0 and read again". This step was missed out earlier and resulted in the daemon spinning continuously rather than getting blocked in 'poll'. This bug was exposed by commit aea585ef8fa65163 introduced as part of sysfs changes in 3.13-rc1. A seek to 0 has been introduced to fix it. Reviewed-by: Sudeep Dutt Signed-off-by: Ashutosh Dixit Signed-off-by: Greg Kroah-Hartman --- Documentation/mic/mpssd/mpssd.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'Documentation') diff --git a/Documentation/mic/mpssd/mpssd.c b/Documentation/mic/mpssd/mpssd.c index 0c980ad40b17..5c7fdda56f0e 100644 --- a/Documentation/mic/mpssd/mpssd.c +++ b/Documentation/mic/mpssd/mpssd.c @@ -1412,6 +1412,12 @@ mic_config(void *arg) } do { + ret = lseek(fd, 0, SEEK_SET); + if (ret < 0) { + mpsslog("%s: Failed to seek to file start '%s': %s\n", + mic->name, pathname, strerror(errno)); + goto close_error1; + } ret = read(fd, value, sizeof(value)); if (ret < 0) { mpsslog("%s: Failed to read sysfs entry '%s': %s\n", -- cgit v1.2.3 From 1e31aa9270daab40c7aef9d5488982e3475b87ef Mon Sep 17 00:00:00 2001 From: Ashutosh Dixit Date: Wed, 27 Nov 2013 08:58:41 -0800 Subject: misc: mic: Fix user space namespace pollution from mic_common.h. Avoid declaring ALIGN() and __aligned() in include/uapi/linux/mic_common.h since they pollute user space namespace. Also, mic_aligned_size() can be simply replaced simply by sizeof() since all structures where mic_aligned_size() is used are declared using __attribute__ ((aligned(8))); -- >From mail from H Peter Anvin about this: On Fri, Nov 08, 2013 H Peter Anvin wrote: Subject: Namespace pollution in mic_common.h This puts two macros, ALIGN() and __aligned(), into arbitrary user space namespace. This really isn't safe or acceptable, especially since those symbols are highly generic. ... When these structures are forced-aligned, they will in fact have padding automatically added by the compiler to an 8-byte boundary anyway, so mic_aligned_size() does nothing. ... Reported-by: H Peter Anvin Reviewed-by: Sudeep Dutt Signed-off-by: Nikhil Rao Signed-off-by: Ashutosh Dixit Signed-off-by: Greg Kroah-Hartman --- Documentation/mic/mpssd/mpssd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/mic/mpssd/mpssd.c b/Documentation/mic/mpssd/mpssd.c index 5c7fdda56f0e..91f9e8e4ef7b 100644 --- a/Documentation/mic/mpssd/mpssd.c +++ b/Documentation/mic/mpssd/mpssd.c @@ -313,7 +313,7 @@ static struct mic_device_desc *get_device_desc(struct mic_info *mic, int type) int i; void *dp = get_dp(mic, type); - for (i = mic_aligned_size(struct mic_bootparam); i < PAGE_SIZE; + for (i = sizeof(struct mic_bootparam); i < PAGE_SIZE; i += mic_total_desc_size(d)) { d = dp + i; @@ -520,7 +520,7 @@ static void * virtio_net(void *arg) { static __u8 vnet_hdr[2][sizeof(struct virtio_net_hdr)]; - static __u8 vnet_buf[2][MAX_NET_PKT_SIZE] __aligned(64); + static __u8 vnet_buf[2][MAX_NET_PKT_SIZE] __attribute__ ((aligned(64))); struct iovec vnet_iov[2][2] = { { { .iov_base = vnet_hdr[0], .iov_len = sizeof(vnet_hdr[0]) }, { .iov_base = vnet_buf[0], .iov_len = sizeof(vnet_buf[0]) } }, -- cgit v1.2.3 From 173c07278763850bfee57eec442dce38855d6f13 Mon Sep 17 00:00:00 2001 From: Ashutosh Dixit Date: Wed, 27 Nov 2013 08:58:42 -0800 Subject: misc: mic: Fix endianness issues. Endianness issues are now consistent as per the documentation in host/mic_virtio.h. Sparse warnings related to endianness are also fixed. Note that the MIC driver implementation assumes that the host can be both BE or LE whereas the card is always LE. Reported-by: Fengguang Wu Reviewed-by: Sudeep Dutt Reviewed-by: Nikhil Rao Signed-off-by: Ashutosh Dixit Signed-off-by: Greg Kroah-Hartman --- Documentation/mic/mpssd/mpssd.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/mic/mpssd/mpssd.c b/Documentation/mic/mpssd/mpssd.c index 91f9e8e4ef7b..4d17487d5ad9 100644 --- a/Documentation/mic/mpssd/mpssd.c +++ b/Documentation/mic/mpssd/mpssd.c @@ -445,8 +445,8 @@ init_vr(struct mic_info *mic, int fd, int type, __func__, mic->name, vr0->va, vr0->info, vr_size, vring_size(MIC_VRING_ENTRIES, MIC_VIRTIO_RING_ALIGN)); mpsslog("magic 0x%x expected 0x%x\n", - vr0->info->magic, MIC_MAGIC + type); - assert(vr0->info->magic == MIC_MAGIC + type); + le32toh(vr0->info->magic), MIC_MAGIC + type); + assert(le32toh(vr0->info->magic) == MIC_MAGIC + type); if (vr1) { vr1->va = (struct mic_vring *) &va[MIC_DEVICE_PAGE_END + vr_size]; @@ -458,8 +458,8 @@ init_vr(struct mic_info *mic, int fd, int type, __func__, mic->name, vr1->va, vr1->info, vr_size, vring_size(MIC_VRING_ENTRIES, MIC_VIRTIO_RING_ALIGN)); mpsslog("magic 0x%x expected 0x%x\n", - vr1->info->magic, MIC_MAGIC + type + 1); - assert(vr1->info->magic == MIC_MAGIC + type + 1); + le32toh(vr1->info->magic), MIC_MAGIC + type + 1); + assert(le32toh(vr1->info->magic) == MIC_MAGIC + type + 1); } done: return va; -- cgit v1.2.3 From dad337501d490b26fbf8d83baee99c788461c61c Mon Sep 17 00:00:00 2001 From: Dave Jones Date: Wed, 27 Nov 2013 15:15:57 -0500 Subject: remove obsolete references to powertweak This tool hasn't been maintained in over a decade, and is pretty much useless these days. Let's pretend it never happened. Also remove a long-dead email address. Signed-off-by: Dave Jones Signed-off-by: Linus Torvalds --- Documentation/Changes | 11 ----------- 1 file changed, 11 deletions(-) (limited to 'Documentation') diff --git a/Documentation/Changes b/Documentation/Changes index b17580885273..07c75d18154e 100644 --- a/Documentation/Changes +++ b/Documentation/Changes @@ -196,13 +196,6 @@ chmod 0644 /dev/cpu/microcode as root before you can use this. You'll probably also want to get the user-space microcode_ctl utility to use with this. -Powertweak ----------- - -If you are running v0.1.17 or earlier, you should upgrade to -version v0.99.0 or higher. Running old versions may cause problems -with programs using shared memory. - udev ---- udev is a userspace application for populating /dev dynamically with @@ -366,10 +359,6 @@ Intel P6 microcode ------------------ o -Powertweak ----------- -o - udev ---- o -- cgit v1.2.3 From 96d5d9d9e8b7925357737a49bdd1091543dde010 Mon Sep 17 00:00:00 2001 From: Nicolas Dichtel Date: Wed, 20 Nov 2013 09:50:28 +0100 Subject: doc: fix generation of device-drivers Since commit 7a6354e241d8 ("sched: Move wait.c into kernel/sched/"), the path of this file has changed. Signed-off-by: Nicolas Dichtel Acked-by: Randy Dunlap Acked-by: Andy Whitcroft Cc: Peter Zijlstra Cc: Ingo Molnar Signed-off-by: Linus Torvalds --- Documentation/DocBook/device-drivers.tmpl | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/DocBook/device-drivers.tmpl b/Documentation/DocBook/device-drivers.tmpl index 6c9d9d37c83a..f5170082bdb3 100644 --- a/Documentation/DocBook/device-drivers.tmpl +++ b/Documentation/DocBook/device-drivers.tmpl @@ -58,7 +58,7 @@ Wait queues and Wake events !Iinclude/linux/wait.h -!Ekernel/wait.c +!Ekernel/sched/wait.c High-resolution timers !Iinclude/linux/ktime.h -- cgit v1.2.3 From 23fd78d76415729b338ff1802a0066b4a62f7fb8 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 2 Dec 2013 11:24:18 +0000 Subject: KEYS: Fix multiple key add into associative array If sufficient keys (or keyrings) are added into a keyring such that a node in the associative array's tree overflows (each node has a capacity N, currently 16) and such that all N+1 keys have the same index key segment for that level of the tree (the level'th nibble of the index key), then assoc_array_insert() calls ops->diff_objects() to indicate at which bit position the two index keys vary. However, __key_link_begin() passes a NULL object to assoc_array_insert() with the intention of supplying the correct pointer later before we commit the change. This means that keyring_diff_objects() is given a NULL pointer as one of its arguments which it does not expect. This results in an oops like the attached. With the previous patch to fix the keyring hash function, this can be forced much more easily by creating a keyring and only adding keyrings to it. Add any other sort of key and a different insertion path is taken - all 16+1 objects must want to cluster in the same node slot. This can be tested by: r=`keyctl newring sandbox @s` for ((i=0; i<=16; i++)); do keyctl newring ring$i $r; done This should work fine, but oopses when the 17th keyring is added. Since ops->diff_objects() is always called with the first pointer pointing to the object to be inserted (ie. the NULL pointer), we can fix the problem by changing the to-be-inserted object pointer to point to the index key passed into assoc_array_insert() instead. Whilst we're at it, we also switch the arguments so that they are the same as for ->compare_object(). BUG: unable to handle kernel NULL pointer dereference at 0000000000000088 IP: [] hash_key_type_and_desc+0x18/0xb0 ... RIP: 0010:[] hash_key_type_and_desc+0x18/0xb0 ... Call Trace: [] keyring_diff_objects+0x21/0xd2 [] assoc_array_insert+0x3b6/0x908 [] __key_link_begin+0x78/0xe5 [] key_create_or_update+0x17d/0x36a [] SyS_add_key+0x123/0x183 [] tracesys+0xdd/0xe2 Signed-off-by: David Howells Tested-by: Stephen Gallagher --- Documentation/assoc_array.txt | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/assoc_array.txt b/Documentation/assoc_array.txt index f4faec0f66e4..2f2c6cdd73c0 100644 --- a/Documentation/assoc_array.txt +++ b/Documentation/assoc_array.txt @@ -164,10 +164,10 @@ This points to a number of methods, all of which need to be provided: (4) Diff the index keys of two objects. - int (*diff_objects)(const void *a, const void *b); + int (*diff_objects)(const void *object, const void *index_key); - Return the bit position at which the index keys of two objects differ or - -1 if they are the same. + Return the bit position at which the index key of the specified object + differs from the given index key or -1 if they are the same. (5) Free an object. -- cgit v1.2.3 From f04bda90392b729fea9b0420b2a87aa6f2abfcd9 Mon Sep 17 00:00:00 2001 From: Rob Herring Date: Thu, 7 Nov 2013 20:58:16 -0600 Subject: dt-bindings: add ARMv8 PMU binding Add missing "arm,armv8-pmuv3" compatible property for ARMv8 PMU. Signed-off-by: Rob Herring Cc: Will Deacon Cc: Pawel Moll Acked-by: Mark Rutland Cc: Ian Campbell --- Documentation/devicetree/bindings/arm/pmu.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/arm/pmu.txt b/Documentation/devicetree/bindings/arm/pmu.txt index 343781b9f246..3e1e498fea96 100644 --- a/Documentation/devicetree/bindings/arm/pmu.txt +++ b/Documentation/devicetree/bindings/arm/pmu.txt @@ -7,6 +7,7 @@ representation in the device tree should be done as under:- Required properties: - compatible : should be one of + "arm,armv8-pmuv3" "arm,cortex-a15-pmu" "arm,cortex-a9-pmu" "arm,cortex-a8-pmu" -- cgit v1.2.3 From f1e8e3811486b858bcc7190477bc6e4ea8f3488c Mon Sep 17 00:00:00 2001 From: Sricharan R Date: Fri, 8 Nov 2013 16:08:48 +0530 Subject: ARM: dts: doc: Document missing binding for omap5-mpu The binding and support for omap5-mpu which has a cortex-a15 smp core, gic and integrated L2 cache has been existing for sometime. So Documenting the missing binding here. Cc: Benoit Cousson Signed-off-by: Sricharan R Signed-off-by: Rob Herring --- Documentation/devicetree/bindings/arm/omap/mpu.txt | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/arm/omap/mpu.txt b/Documentation/devicetree/bindings/arm/omap/mpu.txt index 1a5a42ce21bb..83f405bde138 100644 --- a/Documentation/devicetree/bindings/arm/omap/mpu.txt +++ b/Documentation/devicetree/bindings/arm/omap/mpu.txt @@ -7,10 +7,18 @@ The MPU contain CPUs, GIC, L2 cache and a local PRCM. Required properties: - compatible : Should be "ti,omap3-mpu" for OMAP3 Should be "ti,omap4-mpu" for OMAP4 + Should be "ti,omap5-mpu" for OMAP5 - ti,hwmods: "mpu" Examples: +- For an OMAP5 SMP system: + +mpu { + compatible = "ti,omap5-mpu"; + ti,hwmods = "mpu" +}; + - For an OMAP4 SMP system: mpu { -- cgit v1.2.3 From 21ea02686164a71f1d464835c602c3fe2a0f3d61 Mon Sep 17 00:00:00 2001 From: Fabio Estevam Date: Mon, 18 Nov 2013 11:28:07 -0200 Subject: Documentation: net: fsl-fec.txt: Add phy-supply entry phy-supply is an optional property of the fec driver, so add it to the binding documentation. Signed-off-by: Fabio Estevam Signed-off-by: Rob Herring --- Documentation/devicetree/bindings/net/fsl-fec.txt | 2 ++ 1 file changed, 2 insertions(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/net/fsl-fec.txt b/Documentation/devicetree/bindings/net/fsl-fec.txt index d53639221403..845ff848d895 100644 --- a/Documentation/devicetree/bindings/net/fsl-fec.txt +++ b/Documentation/devicetree/bindings/net/fsl-fec.txt @@ -15,6 +15,7 @@ Optional properties: only if property "phy-reset-gpios" is available. Missing the property will have the duration be 1 millisecond. Numbers greater than 1000 are invalid and 1 millisecond will be used instead. +- phy-supply: regulator that powers the Ethernet PHY. Example: @@ -25,4 +26,5 @@ ethernet@83fec000 { phy-mode = "mii"; phy-reset-gpios = <&gpio2 14 0>; /* GPIO2_14 */ local-mac-address = [00 04 9F 01 1B B9]; + phy-supply = <®_fec_supply>; }; -- cgit v1.2.3 From 53d6b36020c76b7d77514ec08394a75cb9deab08 Mon Sep 17 00:00:00 2001 From: Thierry Reding Date: Mon, 18 Nov 2013 11:11:19 +0100 Subject: of: Add vendor prefix for LG Corporation Signed-off-by: Thierry Reding Signed-off-by: Rob Herring --- Documentation/devicetree/bindings/vendor-prefixes.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt index ce95ed1c6d3e..e986fbe26465 100644 --- a/Documentation/devicetree/bindings/vendor-prefixes.txt +++ b/Documentation/devicetree/bindings/vendor-prefixes.txt @@ -38,6 +38,7 @@ ibm International Business Machines (IBM) idt Integrated Device Technologies, Inc. img Imagination Technologies Ltd. intercontrol Inter Control Group +lg LG Corporation linux Linux-specific binding lsi LSI Corp. (LSI Logic) marvell Marvell Technology Group Ltd. -- cgit v1.2.3 From cdbea09819fc5f2ad84f1ffa218999632f0857a7 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Mon, 18 Nov 2013 12:46:12 +0100 Subject: clk: exynos: Fix typos in DT bindings documentation s/comptible/compatible/ Signed-off-by: Laurent Pinchart Reviewed-by: Sachin Kamat Signed-off-by: Rob Herring --- Documentation/devicetree/bindings/clock/exynos4-clock.txt | 2 +- Documentation/devicetree/bindings/clock/exynos5250-clock.txt | 2 +- Documentation/devicetree/bindings/clock/exynos5420-clock.txt | 2 +- Documentation/devicetree/bindings/clock/exynos5440-clock.txt | 2 +- 4 files changed, 4 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/clock/exynos4-clock.txt b/Documentation/devicetree/bindings/clock/exynos4-clock.txt index c6bf8a6c8f52..a2ac2d9ac71a 100644 --- a/Documentation/devicetree/bindings/clock/exynos4-clock.txt +++ b/Documentation/devicetree/bindings/clock/exynos4-clock.txt @@ -6,7 +6,7 @@ SoC's in the Exynos4 family. Required Properties: -- comptible: should be one of the following. +- compatible: should be one of the following. - "samsung,exynos4210-clock" - controller compatible with Exynos4210 SoC. - "samsung,exynos4412-clock" - controller compatible with Exynos4412 SoC. diff --git a/Documentation/devicetree/bindings/clock/exynos5250-clock.txt b/Documentation/devicetree/bindings/clock/exynos5250-clock.txt index 24765c146e31..46f5c791ea0d 100644 --- a/Documentation/devicetree/bindings/clock/exynos5250-clock.txt +++ b/Documentation/devicetree/bindings/clock/exynos5250-clock.txt @@ -5,7 +5,7 @@ controllers within the Exynos5250 SoC. Required Properties: -- comptible: should be one of the following. +- compatible: should be one of the following. - "samsung,exynos5250-clock" - controller compatible with Exynos5250 SoC. - reg: physical base address of the controller and length of memory mapped diff --git a/Documentation/devicetree/bindings/clock/exynos5420-clock.txt b/Documentation/devicetree/bindings/clock/exynos5420-clock.txt index 32aa34ecad36..458f34789e5d 100644 --- a/Documentation/devicetree/bindings/clock/exynos5420-clock.txt +++ b/Documentation/devicetree/bindings/clock/exynos5420-clock.txt @@ -5,7 +5,7 @@ controllers within the Exynos5420 SoC. Required Properties: -- comptible: should be one of the following. +- compatible: should be one of the following. - "samsung,exynos5420-clock" - controller compatible with Exynos5420 SoC. - reg: physical base address of the controller and length of memory mapped diff --git a/Documentation/devicetree/bindings/clock/exynos5440-clock.txt b/Documentation/devicetree/bindings/clock/exynos5440-clock.txt index 4499e9966bc9..9955dc9c7d96 100644 --- a/Documentation/devicetree/bindings/clock/exynos5440-clock.txt +++ b/Documentation/devicetree/bindings/clock/exynos5440-clock.txt @@ -5,7 +5,7 @@ controllers within the Exynos5440 SoC. Required Properties: -- comptible: should be "samsung,exynos5440-clock". +- compatible: should be "samsung,exynos5440-clock". - reg: physical base address of the controller and length of memory mapped region. -- cgit v1.2.3 From dd622d2506a63f0d9cf7b3beaad12f012308a39f Mon Sep 17 00:00:00 2001 From: Wei Ni Date: Wed, 13 Nov 2013 18:59:09 +0800 Subject: of: add vendor prefix for GMT Adding Global Mixed-mode Technology Inc. to the list of devicetree vendor prefixes. Signed-off-by: Wei Ni Acked-by: Stephen Warren Reviewed-by: Jean Delvare Signed-off-by: Rob Herring --- Documentation/devicetree/bindings/vendor-prefixes.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt index e986fbe26465..edbb8d88c85e 100644 --- a/Documentation/devicetree/bindings/vendor-prefixes.txt +++ b/Documentation/devicetree/bindings/vendor-prefixes.txt @@ -32,6 +32,7 @@ est ESTeem Wireless Modems fsl Freescale Semiconductor GEFanuc GE Fanuc Intelligent Platforms Embedded Systems, Inc. gef GE Fanuc Intelligent Platforms Embedded Systems, Inc. +gmt Global Mixed-mode Technology, Inc. hisilicon Hisilicon Limited. hp Hewlett Packard ibm International Business Machines (IBM) -- cgit v1.2.3 From 1675088f8bc3f955e9bd31418a6b3319487f27bf Mon Sep 17 00:00:00 2001 From: Chanwoo Choi Date: Wed, 23 Oct 2013 10:44:50 +0900 Subject: hwmon: ntc_thermistor: Fix typo (pullup-uV -> pullup-uv) This patch fix typo of property name from 'pullup-uV' to 'pullup-uv'. The ntc_thermistor.c use 'pullup-uv' when parsing dt data. Signed-off-by: Chanwoo Choi Reviewed-by: Jingoo Han Acked-by: Naveen Krishna Chatradhi Reviewed-by: Tomasz Figa Signed-off-by: Rob Herring --- Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt b/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt index 47ada1dff216..5d49f2b37f68 100644 --- a/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt +++ b/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt @@ -49,7 +49,7 @@ adc@12D10000 { /* NTC thermistor is a hwmon device */ ncp15wb473@0 { compatible = "ntc,ncp15wb473"; - pullup-uV = <1800000>; + pullup-uv = <1800000>; pullup-ohm = <47000>; pulldown-ohm = <0>; io-channels = <&adc 4>; -- cgit v1.2.3 From 72d944ec7eeb195db96942d5a9f907a312e23313 Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Mon, 25 Nov 2013 15:37:55 -0700 Subject: ARM: tegra: delete nvidia,tegra20-spi.txt binding This binding shouldn't exist; Tegra20 has two forms of SPI controller that are documented separately in nvidia,tegra20-sflash.txt and nvidia,tegra20-slink.txt. Signed-off-by: Stephen Warren Reviewed-by: Thierry Reding Signed-off-by: Rob Herring --- Documentation/devicetree/bindings/spi/nvidia,tegra20-spi.txt | 5 ----- 1 file changed, 5 deletions(-) delete mode 100644 Documentation/devicetree/bindings/spi/nvidia,tegra20-spi.txt (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/spi/nvidia,tegra20-spi.txt b/Documentation/devicetree/bindings/spi/nvidia,tegra20-spi.txt deleted file mode 100644 index 6b9e51896693..000000000000 --- a/Documentation/devicetree/bindings/spi/nvidia,tegra20-spi.txt +++ /dev/null @@ -1,5 +0,0 @@ -NVIDIA Tegra 2 SPI device - -Required properties: -- compatible : should be "nvidia,tegra20-spi". -- gpios : should specify GPIOs used for chipselect. -- cgit v1.2.3 From 2c0e641a963d073d60cb63c24614c642b6f64b21 Mon Sep 17 00:00:00 2001 From: Gerhard Sittig Date: Thu, 21 Nov 2013 09:41:44 +0100 Subject: dt: binding: reword PowerPC 8xxx GPIO documentation re-format and re-word the device tree binding documentation for MPC8xxx and compatibles, reference the common document for interrupt controllers and remove outdated duplicate SoC specific information Cc: Mark Rutland Cc: Rob Herring Cc: Pawel Moll Cc: Arnd Bergmann Cc: Acked-by: Arnd Bergmann Signed-off-by: Gerhard Sittig Signed-off-by: Rob Herring --- .../devicetree/bindings/gpio/8xxx_gpio.txt | 66 +++++++++++++--------- 1 file changed, 40 insertions(+), 26 deletions(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/gpio/8xxx_gpio.txt b/Documentation/devicetree/bindings/gpio/8xxx_gpio.txt index b0019eb5330e..798cfc9d3839 100644 --- a/Documentation/devicetree/bindings/gpio/8xxx_gpio.txt +++ b/Documentation/devicetree/bindings/gpio/8xxx_gpio.txt @@ -5,16 +5,42 @@ This is for the non-QE/CPM/GUTs GPIO controllers as found on Every GPIO controller node must have #gpio-cells property defined, this information will be used to translate gpio-specifiers. +See bindings/gpio/gpio.txt for details of how to specify GPIO +information for devices. + +The GPIO module usually is connected to the SoC's internal interrupt +controller, see bindings/interrupt-controller/interrupts.txt (the +interrupt client nodes section) for details how to specify this GPIO +module's interrupt. + +The GPIO module may serve as another interrupt controller (cascaded to +the SoC's internal interrupt controller). See the interrupt controller +nodes section in bindings/interrupt-controller/interrupts.txt for +details. Required properties: -- compatible : "fsl,-gpio" followed by "fsl,mpc8349-gpio" for - 83xx, "fsl,mpc8572-gpio" for 85xx and "fsl,mpc8610-gpio" for 86xx. -- #gpio-cells : Should be two. The first cell is the pin number and the - second cell is used to specify optional parameters (currently unused). - - interrupts : Interrupt mapping for GPIO IRQ. - - interrupt-parent : Phandle for the interrupt controller that - services interrupts for this device. -- gpio-controller : Marks the port as GPIO controller. +- compatible: "fsl,-gpio" followed by "fsl,mpc8349-gpio" + for 83xx, "fsl,mpc8572-gpio" for 85xx, or + "fsl,mpc8610-gpio" for 86xx. +- #gpio-cells: Should be two. The first cell is the pin number + and the second cell is used to specify optional + parameters (currently unused). +- interrupt-parent: Phandle for the interrupt controller that + services interrupts for this device. +- interrupts: Interrupt mapping for GPIO IRQ. +- gpio-controller: Marks the port as GPIO controller. + +Optional properties: +- interrupt-controller: Empty boolean property which marks the GPIO + module as an IRQ controller. +- #interrupt-cells: Should be two. Defines the number of integer + cells required to specify an interrupt within + this interrupt controller. The first cell + defines the pin number, the second cell + defines additional flags (trigger type, + trigger polarity). Note that the available + set of trigger conditions supported by the + GPIO module depends on the actual SoC. Example of gpio-controller nodes for a MPC8347 SoC: @@ -22,39 +48,27 @@ Example of gpio-controller nodes for a MPC8347 SoC: #gpio-cells = <2>; compatible = "fsl,mpc8347-gpio", "fsl,mpc8349-gpio"; reg = <0xc00 0x100>; - interrupts = <74 0x8>; interrupt-parent = <&ipic>; + interrupts = <74 0x8>; gpio-controller; + interrupt-controller; + #interrupt-cells = <2>; }; gpio2: gpio-controller@d00 { #gpio-cells = <2>; compatible = "fsl,mpc8347-gpio", "fsl,mpc8349-gpio"; reg = <0xd00 0x100>; - interrupts = <75 0x8>; interrupt-parent = <&ipic>; + interrupts = <75 0x8>; gpio-controller; }; -See booting-without-of.txt for details of how to specify GPIO -information for devices. - -To use GPIO pins as interrupt sources for peripherals, specify the -GPIO controller as the interrupt parent and define GPIO number + -trigger mode using the interrupts property, which is defined like -this: - -interrupts = , where: - - number: GPIO pin (0..31) - - trigger: trigger mode: - 2 = trigger on falling edge - 3 = trigger on both edges - -Example of device using this is: +Example of a peripheral using the GPIO module as an IRQ controller: funkyfpga@0 { compatible = "funky-fpga"; ... - interrupts = <4 3>; interrupt-parent = <&gpio1>; + interrupts = <4 3>; }; -- cgit v1.2.3 From 56a39aac593a7e855bed357b1ce43eeb7a99e7e2 Mon Sep 17 00:00:00 2001 From: Alexandre Courbot Date: Sat, 23 Nov 2013 19:32:20 +0900 Subject: Documentation: gpiolib: add 00-INDEX file Give a short overview of the various GPIO documentation files. Signed-off-by: Alexandre Courbot Signed-off-by: Linus Walleij --- Documentation/gpio/00-INDEX | 14 ++++++++++++++ 1 file changed, 14 insertions(+) create mode 100644 Documentation/gpio/00-INDEX (limited to 'Documentation') diff --git a/Documentation/gpio/00-INDEX b/Documentation/gpio/00-INDEX new file mode 100644 index 000000000000..1de43ae46ae6 --- /dev/null +++ b/Documentation/gpio/00-INDEX @@ -0,0 +1,14 @@ +00-INDEX + - This file +gpio.txt + - Introduction to GPIOs and their kernel interfaces +consumer.txt + - How to obtain and use GPIOs in a driver +driver.txt + - How to write a GPIO driver +board.txt + - How to assign GPIOs to a consumer device and a function +sysfs.txt + - Information about the GPIO sysfs interface +gpio-legacy.txt + - Historical documentation of the deprecated GPIO integer interface -- cgit v1.2.3 From dd0df47dc3548bf2dfdc7b4d65f49b452a9d9701 Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Tue, 3 Dec 2013 15:13:02 -0800 Subject: net: davinci_emac: Fix platform data handling and make usable for am3517 When booted with device tree, we may still have platform data passed as auxdata. For am3517 this is needed for passing the interrupt_enable and interrupt_disable callbacks that access the omap system control module registers. These callback functions will eventually go away when we have a separate system control module driver. Some of the things that are currently passed as platform data we don't need to set up as device tree properties as they are always the same on am3517. So let's use a new compatible flag for those so we can get those from the device tree match data. Also note that we need to fix setting of phy_dev to NULL instead of an empty string as the code later on uses that to find the first phy on the mdio bus. This seems to have been caused by 5d69e0076a72 (net: davinci_emac: switch to new mdio). Signed-off-by: Tony Lindgren Signed-off-by: David S. Miller --- Documentation/devicetree/bindings/net/davinci_emac.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/net/davinci_emac.txt b/Documentation/devicetree/bindings/net/davinci_emac.txt index 48b259e29e87..bad381faf036 100644 --- a/Documentation/devicetree/bindings/net/davinci_emac.txt +++ b/Documentation/devicetree/bindings/net/davinci_emac.txt @@ -4,7 +4,7 @@ This file provides information, what the device node for the davinci_emac interface contains. Required properties: -- compatible: "ti,davinci-dm6467-emac"; +- compatible: "ti,davinci-dm6467-emac" or "ti,am3517-emac" - reg: Offset and length of the register set for the device - ti,davinci-ctrl-reg-offset: offset to control register - ti,davinci-ctrl-mod-reg-offset: offset to control module register -- cgit v1.2.3 From c1b96a236e94d49d9396d0bbceb5524519c5c66e Mon Sep 17 00:00:00 2001 From: Philipp Zabel Date: Tue, 21 May 2013 05:11:35 -0300 Subject: [media] videobuf2: Add support for file access mode flags for DMABUF exporting Currently it is not possible for userspace to map a DMABUF exported buffer with write permissions. This patch allows to also pass O_RDONLY/O_RDWR when exporting the buffer, so that userspace may map it with write permissions. Signed-off-by: Philipp Zabel Signed-off-by: Sylwester Nawrocki Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/vidioc-expbuf.xml | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/DocBook/media/v4l/vidioc-expbuf.xml b/Documentation/DocBook/media/v4l/vidioc-expbuf.xml index e287c8fc803b..4165e7bfa4ff 100644 --- a/Documentation/DocBook/media/v4l/vidioc-expbuf.xml +++ b/Documentation/DocBook/media/v4l/vidioc-expbuf.xml @@ -73,7 +73,8 @@ range from zero to the maximal number of valid planes for the currently active format. For the single-planar API, applications must set plane to zero. Additional flags may be posted in the flags field. Refer to a manual for open() for details. -Currently only O_CLOEXEC is supported. All other fields must be set to zero. +Currently only O_CLOEXEC, O_RDONLY, O_WRONLY, and O_RDWR are supported. All +other fields must be set to zero. In the case of multi-planar API, every plane is exported separately using multiple VIDIOC_EXPBUF calls. @@ -170,8 +171,9 @@ multi-planar API. Otherwise this value must be set to zero. __u32 flags Flags for the newly created file, currently only -O_CLOEXEC is supported, refer to the manual of open() for more -details. +O_CLOEXEC , O_RDONLY, O_WRONLY +, and O_RDWR are supported, refer to the manual +of open() for more details. __s32 -- cgit v1.2.3 From 66e56cd46b93ef407c60adcac62cf33b06119d50 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 6 Dec 2013 11:36:15 +0100 Subject: packet: fix send path when running with proto == 0 Commit e40526cb20b5 introduced a cached dev pointer, that gets hooked into register_prot_hook(), __unregister_prot_hook() to update the device used for the send path. We need to fix this up, as otherwise this will not work with sockets created with protocol = 0, plus with sll_protocol = 0 passed via sockaddr_ll when doing the bind. So instead, assign the pointer directly. The compiler can inline these helper functions automagically. While at it, also assume the cached dev fast-path as likely(), and document this variant of socket creation as it seems it is not widely used (seems not even the author of TX_RING was aware of that in his reference example [1]). Tested with reproducer from e40526cb20b5. [1] http://wiki.ipxwarzone.com/index.php5?title=Linux_packet_mmap#Example Fixes: e40526cb20b5 ("packet: fix use after free race in send path when dev is released") Signed-off-by: Daniel Borkmann Tested-by: Salam Noureddine Tested-by: Jesper Dangaard Brouer Signed-off-by: David S. Miller --- Documentation/networking/packet_mmap.txt | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'Documentation') diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt index c01223628a87..8e48e3b14227 100644 --- a/Documentation/networking/packet_mmap.txt +++ b/Documentation/networking/packet_mmap.txt @@ -123,6 +123,16 @@ Transmission process is similar to capture as shown below. [shutdown] close() --------> destruction of the transmission socket and deallocation of all associated resources. +Socket creation and destruction is also straight forward, and is done +the same way as in capturing described in the previous paragraph: + + int fd = socket(PF_PACKET, mode, 0); + +The protocol can optionally be 0 in case we only want to transmit +via this socket, which avoids an expensive call to packet_rcv(). +In this case, you also need to bind(2) the TX_RING with sll_protocol = 0 +set. Otherwise, htons(ETH_P_ALL) or any other protocol, for example. + Binding the socket to your network interface is mandatory (with zero copy) to know the header size of frames used in the circular buffer. -- cgit v1.2.3 From 83f539e1a45a07934f0da69dc545bcbde01de36c Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Tue, 26 Nov 2013 11:03:54 -0500 Subject: dm cache: update Documentation for invalidate_cblocks's range syntax The cache target's invalidate_cblocks message allows cache block (cblock) ranges to be expressed with: - The range's value is "one past the end", so the range includes through -1. Signed-off-by: Mike Snitzer Acked-by: Joe Thornber --- Documentation/device-mapper/cache.txt | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/device-mapper/cache.txt b/Documentation/device-mapper/cache.txt index 274752f8bdf9..719320b5ed3f 100644 --- a/Documentation/device-mapper/cache.txt +++ b/Documentation/device-mapper/cache.txt @@ -266,10 +266,12 @@ E.g. Invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the invalidate_cblocks message, which takes an arbitrary number of cblock ranges. Each cblock -must be expressed as a decimal value, in the future a variant message -that takes cblock ranges expressed in hexidecimal may be needed to -better support efficient invalidation of larger caches. The cache must -be in passthrough mode when invalidate_cblocks is used. +range's end value is "one past the end", meaning 5-10 expresses a range +of values from 5 to 9. Each cblock must be expressed as a decimal +value, in the future a variant message that takes cblock ranges +expressed in hexidecimal may be needed to better support efficient +invalidation of larger caches. The cache must be in passthrough mode +when invalidate_cblocks is used. invalidate_cblocks [|-]* -- cgit v1.2.3 From 3f823c15d53dc78b50d6f561caf36e8109df1193 Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Wed, 11 Dec 2013 13:04:27 -0800 Subject: net: smc91x: Fix device tree based configuration so it's usable Commit 89ce376c6bdc (drivers/net: Use of_match_ptr() macro in smc91x.c) added minimal device tree support to smc91x, but it's not working on many platforms because of the lack of some key configuration bits. Fix the issue by parsing the necessary configuration like the smc911x driver is doing. As most smc91x users seem to use 16-bit access, let's default to that if no reg-io-width is specified. Cc: Nicolas Pitre Cc: Mark Rutland Cc: netdev@vger.kernel.org Cc: devicetree@vger.kernel.org Acked-by: Nishanth Menon Signed-off-by: Tony Lindgren Signed-off-by: David S. Miller --- Documentation/devicetree/bindings/net/smsc-lan91c111.txt | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/net/smsc-lan91c111.txt b/Documentation/devicetree/bindings/net/smsc-lan91c111.txt index 953049b4248a..5a41a8658daa 100644 --- a/Documentation/devicetree/bindings/net/smsc-lan91c111.txt +++ b/Documentation/devicetree/bindings/net/smsc-lan91c111.txt @@ -8,3 +8,7 @@ Required properties: Optional properties: - phy-device : phandle to Ethernet phy - local-mac-address : Ethernet mac address to use +- reg-io-width : Mask of sizes (in bytes) of the IO accesses that + are supported on the device. Valid value for SMSC LAN91c111 are + 1, 2 or 4. If it's omitted or invalid, the size would be 2 meaning + 16-bit access only. -- cgit v1.2.3