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Diffstat (limited to 'include/linux/iio/buffer_impl.h')
| -rw-r--r-- | include/linux/iio/buffer_impl.h | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/include/linux/iio/buffer_impl.h b/include/linux/iio/buffer_impl.h new file mode 100644 index 000000000..89c3fd7c2 --- /dev/null +++ b/include/linux/iio/buffer_impl.h @@ -0,0 +1,168 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _IIO_BUFFER_GENERIC_IMPL_H_ +#define _IIO_BUFFER_GENERIC_IMPL_H_ +#include <linux/sysfs.h> +#include <linux/kref.h> + +#ifdef CONFIG_IIO_BUFFER + +#include <uapi/linux/iio/buffer.h> +#include <linux/iio/buffer.h> + +struct iio_dev; +struct iio_buffer; + +/** + * INDIO_BUFFER_FLAG_FIXED_WATERMARK - Watermark level of the buffer can not be + * configured. It has a fixed value which will be buffer specific. + */ +#define INDIO_BUFFER_FLAG_FIXED_WATERMARK BIT(0) + +/** + * struct iio_buffer_access_funcs - access functions for buffers. + * @store_to: actually store stuff to the buffer + * @read: try to get a specified number of bytes (must exist) + * @data_available: indicates how much data is available for reading from + * the buffer. + * @remove_from: remove scan from buffer. Drivers should calls this to + * remove a scan from a buffer. + * @write: try to write a number of bytes + * @space_available: returns the amount of bytes available in a buffer + * @request_update: if a parameter change has been marked, update underlying + * storage. + * @set_bytes_per_datum:set number of bytes per datum + * @set_length: set number of datums in buffer + * @enable: called if the buffer is attached to a device and the + * device starts sampling. Calls are balanced with + * @disable. + * @disable: called if the buffer is attached to a device and the + * device stops sampling. Calles are balanced with @enable. + * @release: called when the last reference to the buffer is dropped, + * should free all resources allocated by the buffer. + * @modes: Supported operating modes by this buffer type + * @flags: A bitmask combination of INDIO_BUFFER_FLAG_* + * + * The purpose of this structure is to make the buffer element + * modular as event for a given driver, different usecases may require + * different buffer designs (space efficiency vs speed for example). + * + * It is worth noting that a given buffer implementation may only support a + * small proportion of these functions. The core code 'should' cope fine with + * any of them not existing. + **/ +struct iio_buffer_access_funcs { + int (*store_to)(struct iio_buffer *buffer, const void *data); + int (*read)(struct iio_buffer *buffer, size_t n, char __user *buf); + size_t (*data_available)(struct iio_buffer *buffer); + int (*remove_from)(struct iio_buffer *buffer, void *data); + int (*write)(struct iio_buffer *buffer, size_t n, const char __user *buf); + size_t (*space_available)(struct iio_buffer *buffer); + + int (*request_update)(struct iio_buffer *buffer); + + int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd); + int (*set_length)(struct iio_buffer *buffer, unsigned int length); + + int (*enable)(struct iio_buffer *buffer, struct iio_dev *indio_dev); + int (*disable)(struct iio_buffer *buffer, struct iio_dev *indio_dev); + + void (*release)(struct iio_buffer *buffer); + + unsigned int modes; + unsigned int flags; +}; + +/** + * struct iio_buffer - general buffer structure + * + * Note that the internals of this structure should only be of interest to + * those writing new buffer implementations. + */ +struct iio_buffer { + /** @length: Number of datums in buffer. */ + unsigned int length; + + /** @flags: File ops flags including busy flag. */ + unsigned long flags; + + /** @bytes_per_datum: Size of individual datum including timestamp. */ + size_t bytes_per_datum; + + /* @direction: Direction of the data stream (in/out). */ + enum iio_buffer_direction direction; + + /** + * @access: Buffer access functions associated with the + * implementation. + */ + const struct iio_buffer_access_funcs *access; + + /** @scan_mask: Bitmask used in masking scan mode elements. */ + long *scan_mask; + + /** @demux_list: List of operations required to demux the scan. */ + struct list_head demux_list; + + /** @pollq: Wait queue to allow for polling on the buffer. */ + wait_queue_head_t pollq; + + /** @watermark: Number of datums to wait for poll/read. */ + unsigned int watermark; + + /* private: */ + /* @scan_timestamp: Does the scan mode include a timestamp. */ + bool scan_timestamp; + + /* @buffer_attr_list: List of buffer attributes. */ + struct list_head buffer_attr_list; + + /* + * @buffer_group: Attributes of the new buffer group. + * Includes scan elements attributes. + */ + struct attribute_group buffer_group; + + /* @attrs: Standard attributes of the buffer. */ + const struct iio_dev_attr **attrs; + + /* @demux_bounce: Buffer for doing gather from incoming scan. */ + void *demux_bounce; + + /* @attached_entry: Entry in the devices list of buffers attached by the driver. */ + struct list_head attached_entry; + + /* @buffer_list: Entry in the devices list of current buffers. */ + struct list_head buffer_list; + + /* @ref: Reference count of the buffer. */ + struct kref ref; +}; + +/** + * iio_update_buffers() - add or remove buffer from active list + * @indio_dev: device to add buffer to + * @insert_buffer: buffer to insert + * @remove_buffer: buffer_to_remove + * + * Note this will tear down the all buffering and build it up again + */ +int iio_update_buffers(struct iio_dev *indio_dev, + struct iio_buffer *insert_buffer, + struct iio_buffer *remove_buffer); + +/** + * iio_buffer_init() - Initialize the buffer structure + * @buffer: buffer to be initialized + **/ +void iio_buffer_init(struct iio_buffer *buffer); + +struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer); +void iio_buffer_put(struct iio_buffer *buffer); + +#else /* CONFIG_IIO_BUFFER */ + +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_IMPL_H_ */ |