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/*
* Memory-to-memory device framework for Video for Linux 2.
*
* Helper functions for devices that use memory buffers for both source
* and destination.
*
* Copyright (c) 2009 Samsung Electronics Co., Ltd.
* Pawel Osciak, <pawel@osciak.com>
* Marek Szyprowski, <m.szyprowski@samsung.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the
* License, or (at your option) any later version
*/
#ifndef _MEDIA_V4L2_MEM2MEM_H
#define _MEDIA_V4L2_MEM2MEM_H
#include <media/videobuf2-v4l2.h>
/**
* struct v4l2_m2m_ops - mem-to-mem device driver callbacks
* @device_run: required. Begin the actual job (transaction) inside this
* callback.
* The job does NOT have to end before this callback returns
* (and it will be the usual case). When the job finishes,
* v4l2_m2m_job_finish() has to be called.
* @job_ready: optional. Should return 0 if the driver does not have a job
* fully prepared to run yet (i.e. it will not be able to finish a
* transaction without sleeping). If not provided, it will be
* assumed that one source and one destination buffer are all
* that is required for the driver to perform one full transaction.
* This method may not sleep.
* @job_abort: optional. Informs the driver that it has to abort the currently
* running transaction as soon as possible (i.e. as soon as it can
* stop the device safely; e.g. in the next interrupt handler),
* even if the transaction would not have been finished by then.
* After the driver performs the necessary steps, it has to call
* v4l2_m2m_job_finish() (as if the transaction ended normally).
* This function does not have to (and will usually not) wait
* until the device enters a state when it can be stopped.
*/
struct v4l2_m2m_ops {
void (*device_run)(void *priv);
int (*job_ready)(void *priv);
void (*job_abort)(void *priv);
};
struct video_device;
struct v4l2_m2m_dev;
/**
* struct v4l2_m2m_queue_ctx - represents a queue for buffers ready to be
* processed
*
* @q: pointer to struct &vb2_queue
* @rdy_queue: List of V4L2 mem-to-mem queues
* @rdy_spinlock: spin lock to protect the struct usage
* @num_rdy: number of buffers ready to be processed
* @buffered: is the queue buffered?
*
* Queue for buffers ready to be processed as soon as this
* instance receives access to the device.
*/
struct v4l2_m2m_queue_ctx {
struct vb2_queue q;
struct list_head rdy_queue;
spinlock_t rdy_spinlock;
u8 num_rdy;
bool buffered;
};
/**
* struct v4l2_m2m_ctx - Memory to memory context structure
*
* @q_lock: struct &mutex lock
* @m2m_dev: opaque pointer to the internal data to handle M2M context
* @cap_q_ctx: Capture (output to memory) queue context
* @out_q_ctx: Output (input from memory) queue context
* @queue: List of memory to memory contexts
* @job_flags: Job queue flags, used internally by v4l2-mem2mem.c:
* %TRANS_QUEUED, %TRANS_RUNNING and %TRANS_ABORT.
* @finished: Wait queue used to signalize when a job queue finished.
* @priv: Instance private data
*
* The memory to memory context is specific to a file handle, NOT to e.g.
* a device.
*/
struct v4l2_m2m_ctx {
/* optional cap/out vb2 queues lock */
struct mutex *q_lock;
/* internal use only */
struct v4l2_m2m_dev *m2m_dev;
struct v4l2_m2m_queue_ctx cap_q_ctx;
struct v4l2_m2m_queue_ctx out_q_ctx;
/* For device job queue */
struct list_head queue;
unsigned long job_flags;
wait_queue_head_t finished;
void *priv;
};
/**
* struct v4l2_m2m_buffer - Memory to memory buffer
*
* @vb: pointer to struct &vb2_v4l2_buffer
* @list: list of m2m buffers
*/
struct v4l2_m2m_buffer {
struct vb2_v4l2_buffer vb;
struct list_head list;
};
/**
* v4l2_m2m_get_curr_priv() - return driver private data for the currently
* running instance or NULL if no instance is running
*
* @m2m_dev: opaque pointer to the internal data to handle M2M context
*/
void *v4l2_m2m_get_curr_priv(struct v4l2_m2m_dev *m2m_dev);
/**
* v4l2_m2m_get_vq() - return vb2_queue for the given type
*
* @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
* @type: type of the V4L2 buffer, as defined by enum &v4l2_buf_type
*/
struct vb2_queue *v4l2_m2m_get_vq(struct v4l2_m2m_ctx *m2m_ctx,
enum v4l2_buf_type type);
/**
* v4l2_m2m_try_schedule() - check whether an instance is ready to be added to
* the pending job queue and add it if so.
*
* @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
*
* There are three basic requirements an instance has to meet to be able to run:
* 1) at least one source buffer has to be queued,
* 2) at least one destination buffer has to be queued,
* 3) streaming has to be on.
*
* If a queue is buffered (for example a decoder hardware ringbuffer that has
* to be drained before doing streamoff), allow scheduling without v4l2 buffers
* on that queue.
*
* There may also be additional, custom requirements. In such case the driver
* should supply a custom callback (job_ready in v4l2_m2m_ops) that should
* return 1 if the instance is ready.
* An example of the above could be an instance that requires more than one
* src/dst buffer per transaction.
*/
void v4l2_m2m_try_schedule(struct v4l2_m2m_ctx *m2m_ctx);
/**
* v4l2_m2m_job_finish() - inform the framework that a job has been finished
* and have it clean up
*
* @m2m_dev: opaque pointer to the internal data to handle M2M context
* @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
*
* Called by a driver to yield back the device after it has finished with it.
* Should be called as soon as possible after reaching a state which allows
* other instances to take control of the device.
*
* This function has to be called only after &v4l2_m2m_ops->device_run
* callback has been called on the driver. To prevent recursion, it should
* not be called directly from the &v4l2_m2m_ops->device_run callback though.
*/
void v4l2_m2m_job_finish(struct v4l2_m2m_dev *m2m_dev,
struct v4l2_m2m_ctx *m2m_ctx);
static inline void
v4l2_m2m_buf_done(struct vb2_v4l2_buffer *buf, enum vb2_buffer_state state)
{
vb2_buffer_done(&buf->vb2_buf, state);
}
/**
* v4l2_m2m_reqbufs() - multi-queue-aware REQBUFS multiplexer
*
* @file: pointer to struct &file
* @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
* @reqbufs: pointer to struct &v4l2_requestbuffers
*/
int v4l2_m2m_reqbufs(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct v4l2_requestbuffers *reqbufs);
/**
* v4l2_m2m_querybuf() - multi-queue-aware QUERYBUF multiplexer
*
* @file: pointer to struct &file
* @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
* @buf: pointer to struct &v4l2_buffer
*
* See v4l2_m2m_mmap() documentation for details.
*/
int v4l2_m2m_querybuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct v4l2_buffer *buf);
/**
* v4l2_m2m_qbuf() - enqueue a source or destination buffer, depending on
* the type
*
* @file: pointer to struct &file
* @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
* @buf: pointer to struct &v4l2_buffer
*/
int v4l2_m2m_qbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct v4l2_buffer *buf);
/**
* v4l2_m2m_dqbuf() - dequeue a source or destination buffer, depending on
* the type
*
* @file: pointer to struct &file
* @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
* @buf: pointer to struct &v4l2_buffer
*/
int v4l2_m2m_dqbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct v4l2_buffer *buf);
/**
* v4l2_m2m_prepare_buf() - prepare a source or destination buffer, depending on
* the type
*
* @file: pointer to struct &file
* @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
* @buf: pointer to struct &v4l2_buffer
*/
int v4l2_m2m_prepare_buf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct v4l2_buffer *buf);
/**
* v4l2_m2m_create_bufs() - create a source or destination buffer, depending
* on the type
*
* @file: pointer to struct &file
* @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
* @create: pointer to struct &v4l2_create_buffers
*/
int v4l2_m2m_create_bufs(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct v4l2_create_buffers *create);
/**
* v4l2_m2m_expbuf() - export a source or destination buffer, depending on
* the type
*
* @file: pointer to struct &file
* @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
* @eb: pointer to struct &v4l2_exportbuffer
*/
int v4l2_m2m_expbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct v4l2_exportbuffer *eb);
/**
* v4l2_m2m_streamon() - turn on streaming for a video queue
*
* @file: pointer to struct &file
* @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
* @type: type of the V4L2 buffer, as defined by enum &v4l2_buf_type
*/
int v4l2_m2m_streamon(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
enum v4l2_buf_type type);
/**
* v4l2_m2m_streamoff() - turn off streaming for a video queue
*
* @file: pointer to struct &file
* @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
* @type: type of the V4L2 buffer, as defined by enum &v4l2_buf_type
*/
int v4l2_m2m_streamoff(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
enum v4l2_buf_type type);
/**
* v4l2_m2m_poll() - poll replacement, for destination buffers only
*
* @file: pointer to struct &file
* @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
* @wait: pointer to struct &poll_table_struct
*
* Call from the driver's poll() function. Will poll both queues. If a buffer
* is available to dequeue (with dqbuf) from the source queue, this will
* indicate that a non-blocking write can be performed, while read will be
* returned in case of the destination queue.
*/
__poll_t v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct poll_table_struct *wait);
/**
* v4l2_m2m_mmap() - source and destination queues-aware mmap multiplexer
*
* @file: pointer to struct &file
* @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
* @vma: pointer to struct &vm_area_struct
*
* Call from driver's mmap() function. Will handle mmap() for both queues
* seamlessly for videobuffer, which will receive normal per-queue offsets and
* proper videobuf queue pointers. The differentiation is made outside videobuf
* by adding a predefined offset to buffers from one of the queues and
* subtracting it before passing it back to videobuf. Only drivers (and
* thus applications) receive modified offsets.
*/
int v4l2_m2m_mmap(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct vm_area_struct *vma);
/**
* v4l2_m2m_init() - initialize per-driver m2m data
*
* @m2m_ops: pointer to struct v4l2_m2m_ops
*
* Usually called from driver's ``probe()`` function.
*
* Return: returns an opaque pointer to the internal data to handle M2M context
*/
struct v4l2_m2m_dev *v4l2_m2m_init(const struct v4l2_m2m_ops *m2m_ops);
#if defined(CONFIG_MEDIA_CONTROLLER)
void v4l2_m2m_unregister_media_controller(struct v4l2_m2m_dev *m2m_dev);
int v4l2_m2m_register_media_controller(struct v4l2_m2m_dev *m2m_dev,
struct video_device *vdev, int function);
#else
static inline void
v4l2_m2m_unregister_media_controller(struct v4l2_m2m_dev *m2m_dev)
{
}
static inline int
v4l2_m2m_register_media_controller(struct v4l2_m2m_dev *m2m_dev,
struct video_device *vdev, int function)
{
return 0;
}
#endif
/**
* v4l2_m2m_release() - cleans up and frees a m2m_dev structure
*
* @m2m_dev: opaque pointer to the internal data to handle M2M context
*
* Usually called from driver's ``remove()`` function.
*/
void v4l2_m2m_release(struct v4l2_m2m_dev *m2m_dev);
/**
* v4l2_m2m_ctx_init() - allocate and initialize a m2m context
*
* @m2m_dev: opaque pointer to the internal data to handle M2M context
* @drv_priv: driver's instance private data
* @queue_init: a callback for queue type-specific initialization function
* to be used for initializing videobuf_queues
*
* Usually called from driver's ``open()`` function.
*/
struct v4l2_m2m_ctx *v4l2_m2m_ctx_init(struct v4l2_m2m_dev *m2m_dev,
void *drv_priv,
int
|