From 9e69c935fad9fd5f0550c51e3bd251cd30033136 Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Fri, 4 Oct 2013 12:06:00 +0100 Subject: iio: Add reference counting for buffers Since the buffer is accessed by userspace we can not just free the buffers memory once we are done with it in kernel space. There might still be open file descriptors and userspace still might be accessing the buffer. This patch adds support for reference counting to the IIO buffers. When a buffer is created and initialized its initial reference count is set to 1. Instead of freeing the memory of the buffer the buffer's _free() function will drop that reference again. But only after the last reference to the buffer has been dropped the buffer the buffer's memory will be freed. The IIO device will take a reference to its primary buffer. The patch adds a small helper function for this called iio_device_attach_buffer() which will get a reference to the buffer and assign the buffer to the IIO device. This function must be used instead of assigning the buffer to the device by hand. The reference is only dropped once the IIO device is freed and we can be sure that there are no more open file handles. A reference to a buffer will also be taken whenever the buffer is active to avoid the buffer being freed while data is still being send to it. Signed-off-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron --- include/linux/iio/buffer.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'include/linux') diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h index a1124bdc4cac..6e428d96d570 100644 --- a/include/linux/iio/buffer.h +++ b/include/linux/iio/buffer.h @@ -11,6 +11,7 @@ #define _IIO_BUFFER_GENERIC_H_ #include #include +#include #ifdef CONFIG_IIO_BUFFER @@ -26,6 +27,8 @@ struct iio_buffer; * @set_bytes_per_datum:set number of bytes per datum * @get_length: get number of datums in buffer * @set_length: set number of datums in buffer + * @release: called when the last reference to the buffer is dropped, + * should free all resources allocated by the buffer. * * The purpose of this structure is to make the buffer element * modular as event for a given driver, different usecases may require @@ -47,6 +50,8 @@ struct iio_buffer_access_funcs { int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd); int (*get_length)(struct iio_buffer *buffer); int (*set_length)(struct iio_buffer *buffer, int length); + + void (*release)(struct iio_buffer *buffer); }; /** @@ -67,6 +72,7 @@ struct iio_buffer_access_funcs { * @demux_list: [INTERN] list of operations required to demux the scan. * @demux_bounce: [INTERN] buffer for doing gather from incoming scan. * @buffer_list: [INTERN] entry in the devices list of current buffers. + * @ref: [INTERN] reference count of the buffer. */ struct iio_buffer { int length; @@ -83,6 +89,7 @@ struct iio_buffer { struct list_head demux_list; void *demux_bounce; struct list_head buffer_list; + struct kref ref; }; /** @@ -204,6 +211,24 @@ int iio_sw_buffer_preenable(struct iio_dev *indio_dev); bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev, const unsigned long *mask); +struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer); +void iio_buffer_put(struct iio_buffer *buffer); + +/** + * iio_device_attach_buffer - Attach a buffer to a IIO device + * @indio_dev: The device the buffer should be attached to + * @buffer: The buffer to attach to the device + * + * This function attaches a buffer to a IIO device. The buffer stays attached to + * the device until the device is freed. The function should only be called at + * most once per device. + */ +static inline void iio_device_attach_buffer(struct iio_dev *indio_dev, + struct iio_buffer *buffer) +{ + indio_dev->buffer = iio_buffer_get(buffer); +} + #else /* CONFIG_IIO_BUFFER */ static inline int iio_buffer_register(struct iio_dev *indio_dev, @@ -216,6 +241,9 @@ static inline int iio_buffer_register(struct iio_dev *indio_dev, static inline void iio_buffer_unregister(struct iio_dev *indio_dev) {} +static inline void iio_buffer_get(struct iio_buffer *buffer) {} +static inline void iio_buffer_put(struct iio_buffer *buffer) {} + #endif /* CONFIG_IIO_BUFFER */ #endif /* _IIO_BUFFER_GENERIC_H_ */ -- cgit v1.2.3 From b4e3ac0a204ff1775c69924510f49922a56910a7 Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Mon, 7 Oct 2013 15:11:00 +0100 Subject: iio: Extend the event config interface The event configuration interface of the IIO framework has not been getting the same attention as other parts. As a result it has not seen the same improvements as e.g. the channel interface has seen with the introduction of the channel spec struct. Currently all the event config callbacks take a u64 (the so called event code) to pass all the different information about for which event the callback is invoked. The callback function then has to extract the information it is interested in using some macros with rather long names. Most information encoded in the event code comes straight from the iio_chan_spec struct the event was registered for. Since we always have a handle to the channel spec when we call the event callbacks the first step is to add the channel spec as a parameter to the event callbacks. The two remaining things encoded in the event code are the type and direction of the event. Instead of passing them in one parameter, add one parameter for each of them and remove the eventcode from the event callbacks. The patch also adds a new iio_event_info parameter to the {read,write}_event_value callbacks. This makes it possible, similar to the iio_chan_info_enum for channels, to specify additional properties other than just the value for an event. Furthermore the new interface will allow to register shared events. This is e.g. useful if a device allows configuring a threshold event, but the threshold setting is the same for all channels. To implement this the patch adds a new iio_event_spec struct which is similar to the iio_chan_spec struct. It as two field to specify the type and the direction of the event. Furthermore it has a mask field for each one of the different iio_shared_by types. These mask fields holds which kind of attributes should be registered for the event. Creation of the attributes follows the same rules as the for the channel attributes. E.g. for the separate_mask there will be a attribute for each channel with this event, for the shared_by_type there will only be one attribute per channel type. The iio_chan_spec struct gets two new fields, 'event_spec' and 'num_event_specs', which is used to specify which the events for this channel. These two fields are going to replace the channel's event_mask field. For now both the old and the new event config interface coexist, but over the few patches all drivers will be converted from the old to the new interface. Once that is done all code for supporting the old interface will be removed. Signed-off-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron --- include/linux/iio/events.h | 14 ----------- include/linux/iio/iio.h | 58 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/iio/types.h | 19 +++++++++++++++ 3 files changed, 77 insertions(+), 14 deletions(-) (limited to 'include/linux') diff --git a/include/linux/iio/events.h b/include/linux/iio/events.h index 13ce220c7003..5dab2c41031f 100644 --- a/include/linux/iio/events.h +++ b/include/linux/iio/events.h @@ -26,20 +26,6 @@ struct iio_event_data { #define IIO_GET_EVENT_FD_IOCTL _IOR('i', 0x90, int) -enum iio_event_type { - IIO_EV_TYPE_THRESH, - IIO_EV_TYPE_MAG, - IIO_EV_TYPE_ROC, - IIO_EV_TYPE_THRESH_ADAPTIVE, - IIO_EV_TYPE_MAG_ADAPTIVE, -}; - -enum iio_event_direction { - IIO_EV_DIR_EITHER, - IIO_EV_DIR_RISING, - IIO_EV_DIR_FALLING, -}; - /** * IIO_EVENT_CODE() - create event identifier * @chan_type: Type of the channel. Should be one of enum iio_chan_type. diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h index ac1cb8f1858c..256a90a1bea6 100644 --- a/include/linux/iio/iio.h +++ b/include/linux/iio/iio.h @@ -138,6 +138,29 @@ ssize_t iio_enum_write(struct iio_dev *indio_dev, .private = (uintptr_t)(_e), \ } +/** + * struct iio_event_spec - specification for a channel event + * @type: Type of the event + * @dir: Direction of the event + * @mask_separate: Bit mask of enum iio_event_info values. Attributes + * set in this mask will be registered per channel. + * @mask_shared_by_type: Bit mask of enum iio_event_info values. Attributes + * set in this mask will be shared by channel type. + * @mask_shared_by_dir: Bit mask of enum iio_event_info values. Attributes + * set in this mask will be shared by channel type and + * direction. + * @mask_shared_by_all: Bit mask of enum iio_event_info values. Attributes + * set in this mask will be shared by all channels. + */ +struct iio_event_spec { + enum iio_event_type type; + enum iio_event_direction dir; + unsigned long mask_separate; + unsigned long mask_shared_by_type; + unsigned long mask_shared_by_dir; + unsigned long mask_shared_by_all; +}; + /** * struct iio_chan_spec - specification of a single channel * @type: What type of measurement is the channel making. @@ -163,6 +186,9 @@ ssize_t iio_enum_write(struct iio_dev *indio_dev, * @info_mask_shared_by_all: What information is to be exported that is shared * by all channels. * @event_mask: What events can this channel produce. + * @event_spec: Array of events which should be registered for this + * channel. + * @num_event_specs: Size of the event_spec array. * @ext_info: Array of extended info attributes for this channel. * The array is NULL terminated, the last element should * have its name field set to NULL. @@ -201,6 +227,8 @@ struct iio_chan_spec { long info_mask_shared_by_dir; long info_mask_shared_by_all; long event_mask; + const struct iio_event_spec *event_spec; + unsigned int num_event_specs; const struct iio_chan_spec_ext_info *ext_info; const char *extend_name; const char *datasheet_name; @@ -283,6 +311,12 @@ struct iio_dev; * is event dependant. event_code specifies which event. * @write_event_value: write the value associated with the event. * Meaning is event dependent. + * @read_event_config_new: find out if the event is enabled. New style interface. + * @write_event_config_new: set if the event is enabled. New style interface. + * @read_event_value_new: read a configuration value associated with the event. + * New style interface. + * @write_event_value_new: write a configuration value for the event. New style + * interface. * @validate_trigger: function to validate the trigger when the * current trigger gets changed. * @update_scan_mode: function to configure device and scan buffer when @@ -323,6 +357,30 @@ struct iio_info { int (*write_event_value)(struct iio_dev *indio_dev, u64 event_code, int val); + + int (*read_event_config_new)(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir); + + int (*write_event_config_new)(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir, + int state); + + int (*read_event_value_new)(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir, + enum iio_event_info info, int *val, int *val2); + + int (*write_event_value_new)(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir, + enum iio_event_info info, int val, int val2); + int (*validate_trigger)(struct iio_dev *indio_dev, struct iio_trigger *trig); int (*update_scan_mode)(struct iio_dev *indio_dev, diff --git a/include/linux/iio/types.h b/include/linux/iio/types.h index 88bf0f0d27b4..18339ef4ff5d 100644 --- a/include/linux/iio/types.h +++ b/include/linux/iio/types.h @@ -54,6 +54,25 @@ enum iio_modifier { IIO_MOD_LIGHT_BLUE, }; +enum iio_event_type { + IIO_EV_TYPE_THRESH, + IIO_EV_TYPE_MAG, + IIO_EV_TYPE_ROC, + IIO_EV_TYPE_THRESH_ADAPTIVE, + IIO_EV_TYPE_MAG_ADAPTIVE, +}; + +enum iio_event_info { + IIO_EV_INFO_ENABLE, + IIO_EV_INFO_VALUE, +}; + +enum iio_event_direction { + IIO_EV_DIR_EITHER, + IIO_EV_DIR_RISING, + IIO_EV_DIR_FALLING, +}; + #define IIO_VAL_INT 1 #define IIO_VAL_INT_PLUS_MICRO 2 #define IIO_VAL_INT_PLUS_NANO 3 -- cgit v1.2.3 From ec6670ae53c13d767bdb7b3e37755ad661395380 Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Mon, 7 Oct 2013 15:11:00 +0100 Subject: iio: Add a hysteresis event info attribute For some devices it is possible to configure a hysteresis for threshold (or similar) events. This patch adds a new hysteresis event info type which allows for easy creation and read/write handling of the sysfs attribute. Signed-off-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron --- include/linux/iio/types.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/iio/types.h b/include/linux/iio/types.h index 18339ef4ff5d..4ac928ee31c5 100644 --- a/include/linux/iio/types.h +++ b/include/linux/iio/types.h @@ -65,6 +65,7 @@ enum iio_event_type { enum iio_event_info { IIO_EV_INFO_ENABLE, IIO_EV_INFO_VALUE, + IIO_EV_INFO_HYSTERESIS, }; enum iio_event_direction { -- cgit v1.2.3 From bf741c08af194ed0448799ff2690c8dd3da709e5 Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Mon, 14 Oct 2013 17:49:00 +0100 Subject: iio: Remove unused iio_sw_buffer_preenable() The functionality implemented by iio_sw_buffer_preenable() is now done directly in the IIO core and previous users of iio_sw_buffer_preenable() have all been updated to not use it anymore. It is unused now and can be remove. Signed-off-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron --- include/linux/iio/buffer.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h index 6e428d96d570..15607b45221a 100644 --- a/include/linux/iio/buffer.h +++ b/include/linux/iio/buffer.h @@ -206,8 +206,6 @@ ssize_t iio_buffer_show_enable(struct device *dev, iio_buffer_show_enable, \ iio_buffer_store_enable) -int iio_sw_buffer_preenable(struct iio_dev *indio_dev); - bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev, const unsigned long *mask); -- cgit v1.2.3