/*
* Memory-to-memory device framework for Video for Linux 2 and videobuf.
*
* Helper functions for devices that use videobuf buffers for both their
* source and destination.
*
* Copyright (c) 2009-2010 Samsung Electronics Co., Ltd.
* Pawel Osciak, <p.osciak@samsung.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.
*/
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <media/videobuf-core.h>
#include <media/v4l2-mem2mem.h>
MODULE_DESCRIPTION("Mem to mem device framework for videobuf");
MODULE_AUTHOR("Pawel Osciak, <p.osciak@samsung.com>");
MODULE_LICENSE("GPL");
static bool debug;
module_param(debug, bool, 0644);
#define dprintk(fmt, arg...) \
do { \
if (debug) \
printk(KERN_DEBUG "%s: " fmt, __func__, ## arg);\
} while (0)
/* Instance is already queued on the job_queue */
#define TRANS_QUEUED (1 << 0)
/* Instance is currently running in hardware */
#define TRANS_RUNNING (1 << 1)
/* Offset base for buffers on the destination queue - used to distinguish
* between source and destination buffers when mmapping - they receive the same
* offsets but for different queues */
#define DST_QUEUE_OFF_BASE (1 << 30)
/**
* struct v4l2_m2m_dev - per-device context
* @curr_ctx: currently running instance
* @job_queue: instances queued to run
* @job_spinlock: protects job_queue
* @m2m_ops: driver callbacks
*/
struct v4l2_m2m_dev {
struct v4l2_m2m_ctx *curr_ctx;
struct list_head job_queue;
spinlock_t job_spinlock;
struct v4l2_m2m_ops *m2m_ops;
};
static struct v4l2_m2m_queue_ctx *get_queue_ctx(struct v4l2_m2m_ctx *m2m_ctx,
enum v4l2_buf_type type)
{
switch (type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE:
return &m2m_ctx->cap_q_ctx;
case V4L2_BUF_TYPE_VIDEO_OUTPUT:
return &m2m_ctx->out_q_ctx;
default:
printk(KERN_ERR "Invalid buffer type\n");
return NULL;
}
}
/**
* v4l2_m2m_get_vq() - return videobuf_queue for the given type
*/
struct videobuf_queue *v4l2_m2m_get_vq(struct v4l2_m2m_ctx *m2m_ctx,
enum v4l2_buf_type type)
{
struct v4l2_m2m_queue_ctx *q_ctx;
q_ctx = get_queue_ctx(m2m_ctx, type);
if (!q_ctx)
return NULL;
return &q_ctx->q;
}
EXPORT_SYMBOL(v4l2_m2m_get_vq);
/**
* v4l2_m2m_next_buf() - return next buffer from the list of ready buffers
*/
void *v4l2_m2m_next_buf(struct v4l2_m2m_ctx *m2m_ctx, enum v4l2_buf_type type)
{
struct v4l2_m2m_queue_ctx *q_ctx;
struct videobuf_buffer *vb = NULL;
unsigned long flags;
q_ctx = get_queue_ctx(m2m_ctx, type);
if (!q_ctx)
return NULL;
spin_lock_irqsave(q_ctx->q.irqlock, flags);
if (list_empty(&q_ctx->rdy_queue))
goto end;
vb = list_entry(q_ctx->rdy_queue.next, struct videobuf_buffer, queue);
vb->state = VIDEOBUF_ACTIVE;
end:
spin_unlock_irqrestore(q_ctx->q.irqlock, flags);
return vb;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_next_buf);
/**
* v4l2_m2m_buf_remove() - take off a buffer from the list of ready buffers and
* return it
*/
void *v4l2_m2m_buf_remove(struct v4l2_m2m_ctx *m2m_ctx, enum v4l2_buf_type type)
{
struct v4l2_m2m_queue_ctx *q_ctx;
struct videobuf_buffer *vb = NULL;
unsigned long flags;
q_ctx = get_queue_ctx(m2m_ctx, type);
if (!q_ctx)
return NULL;
spin_lock_irqsave(q_ctx->q.irqlock, flags);
if (!list_empty(&q_ctx->rdy_queue)) {
vb = list_entry(q_ctx->rdy_queue.next, struct videobuf_buffer,
queue);
list_del(&vb->queue);
q_ctx->num_rdy--;
}
spin_unlock_irqrestore(q_ctx->q.irqlock, flags);
return vb;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_buf_remove);
/*
* Scheduling handlers
*/
/**
* v4l2_m2m_get_curr_priv() - return driver private data for the currently
* running instance or NULL if no instance is running
*/
void *v4l2_m2m_get_curr_priv(struct v4l2_m2m_dev *m2m_dev)
{
unsigned long flags;
void *ret = NULL;
spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
if (m2m_dev->curr_ctx)
ret = m2m_dev->curr_ctx->priv;
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
return ret;
}
EXPORT_SYMBOL(v4l2_m2m_get_curr_priv);
/**
* v4l2_m2m_try_run() - select next job to perform and run it if possible
*
* Get next transaction (if present) from the waiting jobs list and run it.
*/
static void v4l2_m2m_try_run(struct v4l2_m2m_dev *m2m_dev)
{
unsigned long flags;
spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
if (NULL != m2m_dev->curr_ctx) {
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
dprintk("Another instance is running, won't run now\n");
return;
}
if (list_empty(&m2m_dev->job_queue)) {
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
dprintk("No job pending\n");
return;
}
m2m_dev->curr_ctx = list_entry(m2m_dev->job_queue.next,
struct v4l2_m2m_ctx, queue);
m2m_dev->curr_ctx->job_flags |= TRANS_RUNNING;
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
m2m_dev->m2m_ops->device_run(m2m_dev->curr_ctx->priv);
}
/**
* 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 to be checked
*
* 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.
*
* 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.
*/
static void v4l2_m2m_try_schedule(struct v4l2_m2m_ctx *m2m_ctx)
{
struct v4l2_m2m_dev *m2m_dev;
unsigned long flags_job, flags;
m2m_dev = m2m_ctx->m2m_dev;
dprintk("Trying to schedule a job for m2m_ctx: %p\n", m2m_ctx);
if (!m2m_ctx->out_q_ctx.q.streaming
|| !m2m_ctx->cap_q_ctx.q.streaming) {
dprintk("Streaming needs to be on for both queues\n");
return;
}
spin_lock_irqsave(&m2m_dev->job_spinlock, flags_job);
if (m2m_ctx->job_flags & TRANS_QUEUED) {
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
dprintk("On job queue already\n");
return;
}
spin_lock_irqsave(m2m_ctx->out_q_ctx.q.irqlock, flags);
if (list_empty(&m2m_ctx->out_q_ctx.rdy_queue)) {
spin_unlock_irqrestore(m2m_ctx->out_q_ctx.q.irqlock, flags);
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
dprintk("No input buffers available\n");
return;
}
if (list_empty(&m2m_ctx->cap_q_ctx.rdy_queue)) {
spin_unlock_irqrestore(m2m_ctx->out_q_ctx.q.irqlock, flags);
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
dprintk("No output buffers available\n");
return;
}
spin_unlock_irqrestore(m2m_ctx->out_q_ctx.q.irqlock, flags);
if (m2m_dev->m2m_ops->job_ready
&& (!m2m_dev->m2m_ops->job_ready(m2m_ctx->priv))) {
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
dprintk("Driver not ready\n");
return;
}
list_add_tail(&m2m_ctx->queue, &m2m_dev->job_queue);
m2m_ctx->job_flags |= TRANS_QUEUED;
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
v4l2_m2m_try_run(m2m_dev);
}
/**
* v4l2_m2m_job_finish() - inform the framework that a job has been finished
* and have it clean up
*
* 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 device_run() callback has been
* called on the driver. To prevent recursion, it should not be called directly
* from the device_run() callback though.
*/
void v4l2_m2m_job_finish(struct v4l2_m2m_dev *m2m_dev,
struct v4l2_m2m_ctx *m2m_ctx)
{
unsigned long flags;
spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
if (!m2m_dev->curr_ctx || m2m_dev->curr_ctx != m2m_ctx) {
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
dprintk("Called by an instance not currently running\n");
return;
}
list_del(&m2m_dev->curr_ctx->queue);
m2m_dev->curr_ctx->job_flags &= ~(TRANS_QUEUED | TRANS_RUNNING);
m2m_dev->curr_ctx = NULL;
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
/* This instance might have more buffers ready, but since we do not
* allow more than one job on the job_queue per instance, each has
* to be scheduled separately after the previous one finishes. */
v4l2_m2m_try_schedule(m2m_ctx);
v4l2_m2m_try_run(m2m_dev);
}
EXPORT_SYMBOL(v4l2_m2m_job_finish);
/**
* v4l2_m2m_reqbufs() - multi-queue-aware REQBUFS multiplexer
*/
int v4l2_m2m_reqbufs(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct v4l2_requestbuffers *reqbufs)
{
struct videobuf_queue *vq;
vq = v4l2_m2m_get_vq(m2m_ctx, reqbufs->type);
return videobuf_reqbufs(vq, reqbufs);
}
EXPORT_SYMBOL_GPL(v4l2_m2m_reqbufs);
/**
* v4l2_m2m_querybuf() - multi-queue-aware QUERYBUF multiplexer
*
* See v4l2_m2m_mmap() documentation for details.
*/
int v4l2_m2m_querybuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct v4l2_buffer *buf)
{
struct videobuf_queue *vq;
int ret;
vq = v4l2_m2m_get_vq(m2m_ctx, buf->type);
ret = videobuf_querybuf(vq, buf);
if (buf->memory == V4L2_MEMORY_MMAP
&& vq->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
buf->m.offset += DST_QUEUE_OFF_BASE;
}
return ret;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_querybuf);
/**
* v4l2_m2m_qbuf() - enqueue a source or destination buffer, depending on
* the type
*/
int v4l2_m2m_qbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct v4l2_buffer *buf)
{
struct videobuf_queue *vq;
int ret;
vq = v4l2_m2m_get_vq(m2m_ctx, buf->type);
ret = videobuf_qbuf(vq, buf);
if (!ret)
v4l2_m2m_try_schedule(m2m_ctx);
return ret;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_qbuf);
/**
* v4l2_m2m_dqbuf() - dequeue a source or destination buffer, depending on
* the type
*/
int v4l2_m2m_dqbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct v4l2_buffer *buf)
{
struct videobuf_queue *vq;
vq = v4l2_m2m_get_vq(m2m_ctx, buf->type);
return videobuf_dqbuf(vq, buf, file->f_flags & O_NONBLOCK);
}
EXPORT_SYMBOL_GPL(v4l2_m2m_dqbuf);
/**
* v4l2_m2m_streamon() - turn on streaming for a video queue
*/
int v4l2_m2m_streamon(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
enum v4l2_buf_type type)
{
struct videobuf_queue *vq;
int ret;
vq = v4l2_m2m_get_vq(m2m_ctx, type);
ret = videobuf_streamon(vq);
if (!ret)
v4l2_m2m_try_schedule(m2m_ctx);
return ret;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_streamon);
/**
* v4l2_m2m_streamoff() - turn off streaming for a video queue
*/
int v4l2_m2m_streamoff(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
enum v4l2_buf_type type)
{
struct videobuf_queue *vq;
vq = v4l2_m2m_get_vq(m2m_ctx, type);
return videobuf_streamoff(vq);
}
EXPORT_SYMBOL_GPL(v4l2_m2m_streamoff);
/**
* v4l2_m2m_poll() - poll replacement, for destination buffers only
*
* 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.
*/
unsigned int v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct poll_table_struct *wait)
{
struct videobuf_queue *src_q, *dst_q;
struct videobuf_buffer *src_vb = NULL, *dst_vb = NULL;
unsigned int rc = 0;
src_q = v4l2_m2m_get_src_vq(m2m_ctx);
dst_q = v4l2_m2m_get_dst_vq(m2m_ctx);
videobuf_queue_lock(src_q);
videobuf_queue_lock(dst_q);
if (src_q->streaming && !list_empty(&src_q->stream))
src_vb = list_first_entry(&src_q->stream,
struct videobuf_buffer, stream);
if (dst_q->streaming && !list_empty(&dst_q->stream))
dst_vb = list_first_entry(&dst_q->stream,
struct videobuf_buffer, stream);
if (!src_vb && !dst_vb) {
rc = POLLERR;
goto end;
}
if (src_vb) {
poll_wait(file, &src_vb->done, wait);
if (src_vb->state == VIDEOBUF_DONE
|| src_vb->state == VIDEOBUF_ERROR)
rc |= POLLOUT | POLLWRNORM;
}
if (dst_vb) {
poll_wait(file, &dst_vb->done, wait);
if (dst_vb->state == VIDEOBUF_DONE
|| dst_vb->state == VIDEOBUF_ERROR)
rc |= POLLIN | POLLRDNORM;
}
end:
videobuf_queue_unlock(dst_q);
videobuf_queue_unlock(src_q);
return rc;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_poll);
/**
* v4l2_m2m_mmap() - source and destination queues-aware mmap multiplexer
*
* 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)
{
unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
struct videobuf_queue *vq;
if (offset < DST_QUEUE_OFF_BASE) {
vq = v4l2_m2m_get_src_vq(m2m_ctx);
} else {
vq = v4l2_m2m_get_dst_vq(m2m_ctx);
vma->vm_pgoff -= (DST_QUEUE_OFF_BASE >> PAGE_SHIFT);
}
return videobuf_mmap_mapper(vq, vma);
}
EXPORT_SYMBOL(v4l2_m2m_mmap);
/**
* v4l2_m2m_init() - initialize per-driver m2m data
*
* Usually called from driver's probe() function.
*/
struct v4l2_m2m_dev *v4l2_m2m_init(struct v4l2_m2m_ops *m2m_ops)
{
struct v4l2_m2m_dev *m2m_dev;
if (!m2m_ops)
return ERR_PTR(-EINVAL);
BUG_ON(!m2m_ops->device_run);
BUG_ON(!m2m_ops->job_abort);
m2m_dev = kzalloc(sizeof *m2m_dev, GFP_KERNEL);
if (!m2m_dev)
return ERR_PTR(-ENOMEM);
m2m_dev->curr_ctx = NULL;
m2m_dev->m2m_ops = m2m_ops;
INIT_LIST_HEAD(&m2m_dev->job_queue);
spin_lock_init(&m2m_dev->job_spinlock);
return m2m_dev;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_init);
/**
* v4l2_m2m_release() - cleans up and frees a m2m_dev structure
*
* Usually called from driver's remove() function.
*/
void v4l2_m2m_release(struct v4l2_m2m_dev *m2m_dev)
{
kfree(m2m_dev);
}
EXPORT_SYMBOL_GPL(v4l2_m2m_release);
/**
* v4l2_m2m_ctx_init() - allocate and initialize a m2m context
* @priv - driver's instance private data
* @m2m_dev - a previously initialized m2m_dev struct
* @vq_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(void *priv, struct v4l2_m2m_dev *m2m_dev,
void (*vq_init)(void *priv, struct videobuf_queue *,
enum v4l2_buf_type))
{
struct v4l2_m2m_ctx *m2m_ctx;
struct v4l2_m2m_queue_ctx *out_q_ctx, *cap_q_ctx;
if (!vq_init)
return ERR_PTR(-EINVAL);
m2m_ctx = kzalloc(sizeof *m2m_ctx, GFP_KERNEL);
if (!m2m_ctx)
return ERR_PTR(-ENOMEM);
m2m_ctx->priv = priv;
m2m_ctx->m2m_dev = m2m_dev;
out_q_ctx = get_queue_ctx(m2m_ctx, V4L2_BUF_TYPE_VIDEO_OUTPUT);
cap_q_ctx = get_queue_ctx(m2m_ctx, V4L2_BUF_TYPE_VIDEO_CAPTURE);
INIT_LIST_HEAD(&out_q_ctx->rdy_queue);
INIT_LIST_HEAD(&cap_q_ctx->rdy_queue);
INIT_LIST_HEAD(&m2m_ctx->queue);
vq_init(priv, &out_q_ctx->q, V4L2_BUF_TYPE_VIDEO_OUTPUT);
vq_init(priv, &cap_q_ctx->q, V4L2_BUF_TYPE_VIDEO_CAPTURE);
out_q_ctx->q.priv_data = cap_q_ctx->q.priv_data = priv;
return m2m_ctx;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_ctx_init);
/**
* v4l2_m2m_ctx_release() - release m2m context
*
* Usually called from driver's release() function.
*/
void v4l2_m2m_ctx_release(struct v4l2_m2m_ctx *m2m_ctx)
{
struct v4l2_m2m_dev *m2m_dev;
struct videobuf_buffer *vb;
unsigned long flags;
m2m_dev = m2m_ctx->m2m_dev;
spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
if (m2m_ctx->job_flags & TRANS_RUNNING) {
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
m2m_dev->m2m_ops->job_abort(m2m_ctx->priv);
dprintk("m2m_ctx %p running, will wait to complete", m2m_ctx);
vb = v4l2_m2m_next_dst_buf(m2m_ctx);
BUG_ON(NULL == vb);
wait_event(vb->done, vb->state != VIDEOBUF_ACTIVE
&& vb->state != VIDEOBUF_QUEUED);
} else if (m2m_ctx->job_flags & TRANS_QUEUED) {
list_del(&m2m_ctx->queue);
m2m_ctx->job_flags &= ~(TRANS_QUEUED | TRANS_RUNNING);
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
dprintk("m2m_ctx: %p had been on queue and was removed\n",
m2m_ctx);
} else {
/* Do nothing, was not on queue/running */
spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
}
videobuf_stop(&m2m_ctx->cap_q_ctx.q);
videobuf_stop(&m2m_ctx->out_q_ctx.q);
videobuf_mmap_free(&m2m_ctx->cap_q_ctx.q);
videobuf_mmap_free(&m2m_ctx->out_q_ctx.q);
kfree(m2m_ctx);
}
EXPORT_SYMBOL_GPL(v4l2_m2m_ctx_release);
/**
* v4l2_m2m_buf_queue() - add a buffer to the proper ready buffers list.
*
* Call from buf_queue(), videobuf_queue_ops callback.
*
* Locking: Caller holds q->irqlock (taken by videobuf before calling buf_queue
* callback in the driver).
*/
void v4l2_m2m_buf_queue(struct v4l2_m2m_ctx *m2m_ctx, struct videobuf_queue *vq,
struct videobuf_buffer *vb)
{
struct v4l2_m2m_queue_ctx *q_ctx;
q_ctx = get_queue_ctx(m2m_ctx, vq->type);
if (!q_ctx)
return;
list_add_tail(&vb->queue, &q_ctx->rdy_queue);
q_ctx->num_rdy++;
vb->state = VIDEOBUF_QUEUED;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_buf_queue);
