/* 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 dma_buf_attachment; struct dma_fence; struct iio_dev; struct iio_dma_buffer_block; struct iio_buffer; struct sg_table; /** * 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 - must be safe to * call from any context (e.g. must not sleep). * @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. * @attach_dmabuf: called from userspace via ioctl to attach one external * DMABUF. * @detach_dmabuf: called from userspace via ioctl to detach one previously * attached DMABUF. * @enqueue_dmabuf: called from userspace via ioctl to queue this DMABUF * object to this buffer. Requires a valid DMABUF fd, that * was previouly attached to this buffer. * @get_dma_dev: called to get the DMA channel associated with this buffer. * @lock_queue: called when the core needs to lock the buffer queue; * it is used when enqueueing DMABUF objects. * @unlock_queue: used to unlock a previously locked buffer queue * @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); struct iio_dma_buffer_block * (*attach_dmabuf)(struct iio_buffer *buffer, struct dma_buf_attachment *attach); void (*detach_dmabuf)(struct iio_buffer *buffer, struct iio_dma_buffer_block *block); int (*enqueue_dmabuf)(struct iio_buffer *buffer, struct iio_dma_buffer_block *block, struct dma_fence *fence, struct sg_table *sgt, size_t size, bool cyclic); struct device * (*get_dma_dev)(struct iio_buffer *buffer); void (*lock_queue)(struct iio_buffer *buffer); void (*unlock_queue)(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; /* @dmabufs: List of DMABUF attachments */ struct list_head dmabufs; /* P: dmabufs_mutex */ /* @dmabufs_mutex: Protects dmabufs */ struct mutex dmabufs_mutex; }; /** * 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 all the buffering and build it up again * * Returns: 0 on success or -errno on error */ 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); void iio_buffer_signal_dmabuf_done(struct dma_fence *fence, int ret); #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_ */
