linux-toradex.git/drivers/w1/w1.h, branch v4.4.87

w1: optional bundling of netlink kernel replies

2014-05-27T20:56:21+00:00

Applications can submit a set of commands in one packet to the kernel,
and in some cases it is required such as reading the temperature
sensor results.  This adds an option W1_CN_BUNDLE to the flags of
cn_msg to request the kernel to reply in one packet for efficiency.

The cn_msg flags now check for unknown flag values and return an error
if one is seen.  See "Proper handling of unknown flags in system
calls" http://lwn.net/Articles/588444/

This corrects the ack values returned as per the protocol standard,
namely the original ack for status messages and seq + 1 for all others
such as the data returned from a read.

Some of the common variable names have been standardized as follows.
struct cn_msg *cn
struct w1_netlink_msg *msg
struct w1_netlink_cmd *cmd
struct w1_master *dev

When an argument and a function scope variable would collide, add req_
to the argument.

Signed-off-by: David Fries 
Acked-by: Evgeniy Polyakov 
Signed-off-by: Greg Kroah-Hartman

w1: format for DocBook and fixes

2014-02-07T23:40:18+00:00

Switch the code documentation format style to DocBook format, enable
DocBook documentation generation, and fix some comments.

Signed-off-by: David Fries 
Acked-by: Evgeniy Polyakov 
Signed-off-by: Greg Kroah-Hartman

w1: use family_data instead of rom in w1_slave

2014-02-07T23:40:18+00:00

The first line printed from w1_slave gives the context of the w1
device.  So does the second line, but if the CRC check failed, the
second line contains the last successful result.  It is confusing when
it prints the temperature next to the line that might be a previous
conversion and has nothing to do with that printed temperature value.
Modify the code to store the last good conversion in family_data,
which is designed for custom data structures.

Signed-off-by: David Fries 
Acked-by: Evgeniy Polyakov 
Signed-off-by: Greg Kroah-Hartman

w1: reply only to the requester portid

2014-02-07T23:40:17+00:00

Unicast one wire replies back to the sender portid to avoid multiple
programs getting each other's messages, especially as the response
can't be uniquely identified with the sequence coming from the
requesting program when both programs generate the same id.  Continue
to broadcast events such as add/remove master/slave devices.

Signed-off-by: David Fries 
Acked-by: Evgeniy Polyakov 
Signed-off-by: Greg Kroah-Hartman

w1: process w1 netlink commands in w1_process thread

2014-02-07T23:40:17+00:00

Netlink is a socket interface and is expected to be asynchronous.
Clients can now make w1 requests without blocking by making use of the
w1_master thread to process netlink commands which was previously only
used for doing an automatic bus search.

Signed-off-by: David Fries 
Acked-by: Evgeniy Polyakov 
Signed-off-by: Greg Kroah-Hartman

w1: new netlink commands, add/remove/list slaves

2014-02-07T23:40:17+00:00

Introduce new commands to add, remove, and list slave devices through
the netlink interface.  This can be useful to skip the search on a
static network.  They could previously only be added or removed
through automatic search or sysfs, and this allows a program to only
use netlink.

Only allocate memory when needed, so move kzalloc into w1_get_slaves
where it was used.

Signed-off-by: David Fries 
Acked-by: Evgeniy Polyakov 
Signed-off-by: Greg Kroah-Hartman

w1: continue slave search where previous left off

2014-02-07T23:40:17+00:00

Search will detect at most max_slave_count devices per run, if there
are more pick up the next search where the previous left off.

Signed-off-by: David Fries 
Acked-by: Evgeniy Polyakov 
Signed-off-by: Greg Kroah-Hartman

w1: increase w1_max_slave_count, allow write access

2014-02-07T23:40:17+00:00

w1_max_slave_count is only used to abort the search early
or take a fast search (when 1), so there isn't any reason to not allow
it to be updated through sysfs.  Memory is not allocated based on
the current value and 10 is a rather low base number, increasing to
64, and printing a message the first time the count is reached and
there were more devices to discover to let the user know why not
all the devices were found.

Signed-off-by: David Fries 
Acked-by: Evgeniy Polyakov 
Signed-off-by: Greg Kroah-Hartman

w1: fixup search to support abort from netlink

2014-02-07T23:40:17+00:00

Before 63706172f33 "rework kthread_stop()" kthread_should_stop()
always returned false when called from a non-kthread task, after it
would oops as a non-kthread didn't have that structure and netlink was
calling search from a thread which wasn't a kthread.  9d1817cab2f030
"w1: fix oops when w1_search is called from netlink connector",
modified the code to avoid calling kthread_stop from a netlink thread.

Introduce a w1_master flag and bit W1_ABORT_SEARCH to identify abort
to cleanly support both kthread and netlink search abort.  A search
can take seconds to run, so it is important to abort early if the
hardware is removed in the middle of a search.

Signed-off-by: David Fries 
Acked-by: Evgeniy Polyakov 
Cc: Marcin Jurkowski 
Cc: Josh Boyer 
Cc: Sven Geggus 
Signed-off-by: Greg Kroah-Hartman

drivers: w1: make w1_slave::flags long to avoid memory corruption

2013-11-13T03:09:35+00:00

On architectures where long is more then 32 bits, modifying a 32-bit field
with set_bit (and other atomic bit operations) may cause bytes following
the field to by modified.

Because the endianness of the bits within a field is the native endianness
of the CPU[1], on big-endian machines, bit number zero is in the last byte
of the field.

Therefore, `set_bit(0, ptr)' on a 64-bit big-endian machine is roughly
equivalent to `((char *)ptr)[7] |= 1', and since w1 driver uses a 32-bit
field for holding the flags, this causes bytes beyond the field to be
modified.

[1] From Documentation/atomic_ops.txt:

    Native atomic bit operations are defined to operate on objects
    aligned to the size of an "unsigned long" C data type, and are
    least of that size.  The endianness of the bits within each
    "unsigned long" are the native endianness of the cpu.

Signed-off-by: Michal Nazarewicz 
Cc: Evgeniy Polyakov 
Cc: Greg KH 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds