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videobuf-core.c
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/*
* generic helper functions for handling video4linux capture buffers
*
* (c) 2007 Mauro Carvalho Chehab, <[email protected]>
*
* Highly based on video-buf written originally by:
* (c) 2001,02 Gerd Knorr <[email protected]>
* (c) 2006 Mauro Carvalho Chehab, <[email protected]>
* (c) 2006 Ted Walther and John Sokol
*
* 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
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/time32.h>
#include "videobuf-core.h"
#define MAGIC_BUFFER 0x20070728
#define MAGIC_CHECK(is, should) \
do { \
if (unlikely((is) != (should))) { \
printk(KERN_ERR \
"magic mismatch: %x (expected %x)\n", \
is, should); \
BUG(); \
} \
} while (0)
static int debug = 4;
#define dprintk(level, fmt, arg...) \
do { \
if (debug >= level) \
printk(KERN_DEBUG "vbuf: " fmt, ## arg); \
} while (0)
/* --------------------------------------------------------------------- */
#define CALL(q, f, arg...) \
((q->int_ops->f) ? q->int_ops->f(arg) : 0)
#define CALLPTR(q, f, arg...) \
((q->int_ops->f) ? q->int_ops->f(arg) : NULL)
struct videobuf_buffer *videobuf_alloc_vb(struct videobuf_queue *q)
{
struct videobuf_buffer *vb;
BUG_ON(q->msize < sizeof(*vb));
if (!q->int_ops || !q->int_ops->alloc_vb) {
printk(KERN_ERR "No specific ops defined!\n");
BUG();
}
vb = q->int_ops->alloc_vb(q->msize);
if (NULL != vb) {
init_waitqueue_head(&vb->done);
vb->magic = MAGIC_BUFFER;
}
return vb;
}
EXPORT_SYMBOL_GPL(videobuf_alloc_vb);
static int state_neither_active_nor_queued(struct videobuf_queue *q,
struct videobuf_buffer *vb)
{
unsigned long flags;
bool rc;
spin_lock_irqsave(q->irqlock, flags);
rc = vb->state != VIDEOBUF_ACTIVE && vb->state != VIDEOBUF_QUEUED;
spin_unlock_irqrestore(q->irqlock, flags);
return rc;
};
int videobuf_waiton(struct videobuf_queue *q, struct videobuf_buffer *vb,
int non_blocking, int intr)
{
bool is_ext_locked;
int ret = 0;
MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
if (non_blocking) {
if (state_neither_active_nor_queued(q, vb))
return 0;
return -EAGAIN;
}
is_ext_locked = q->ext_lock && mutex_is_locked(q->ext_lock);
/* Release vdev lock to prevent this wait from blocking outside access to
the device. */
if (is_ext_locked)
mutex_unlock(q->ext_lock);
if (intr)
ret = wait_event_interruptible(vb->done,
state_neither_active_nor_queued(q, vb));
else
wait_event(vb->done, state_neither_active_nor_queued(q, vb));
/* Relock */
if (is_ext_locked)
mutex_lock(q->ext_lock);
return ret;
}
EXPORT_SYMBOL_GPL(videobuf_waiton);
int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb,
struct v4l2_framebuffer *fbuf)
{
MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
return CALL(q, iolock, q, vb, fbuf);
}
EXPORT_SYMBOL_GPL(videobuf_iolock);
void *videobuf_queue_to_vaddr(struct videobuf_queue *q,
struct videobuf_buffer *buf)
{
if (q->int_ops->vaddr)
return q->int_ops->vaddr(buf);
return NULL;
}
EXPORT_SYMBOL_GPL(videobuf_queue_to_vaddr);
/* --------------------------------------------------------------------- */
void videobuf_queue_core_init(struct videobuf_queue *q,
const struct videobuf_queue_ops *ops,
struct device *dev,
spinlock_t *irqlock,
enum v4l2_buf_type type,
enum v4l2_field field,
unsigned int msize,
void *priv,
struct videobuf_qtype_ops *int_ops,
struct mutex *ext_lock)
{
BUG_ON(!q);
memset(q, 0, sizeof(*q));
q->irqlock = irqlock;
q->ext_lock = ext_lock;
q->dev = dev;
q->type = type;
q->field = field;
q->msize = msize;
q->ops = ops;
q->priv_data = priv;
q->int_ops = int_ops;
/* All buffer operations are mandatory */
BUG_ON(!q->ops->buf_setup);
BUG_ON(!q->ops->buf_prepare);
BUG_ON(!q->ops->buf_queue);
BUG_ON(!q->ops->buf_release);
/* Lock is mandatory for queue_cancel to work */
BUG_ON(!irqlock);
/* Having implementations for abstract methods are mandatory */
BUG_ON(!q->int_ops);
mutex_init(&q->vb_lock);
init_waitqueue_head(&q->wait);
INIT_LIST_HEAD(&q->stream);
}
EXPORT_SYMBOL_GPL(videobuf_queue_core_init);
/* Locking: Only usage in bttv unsafe find way to remove */
int videobuf_queue_is_busy(struct videobuf_queue *q)
{
int i;
MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
if (q->streaming) {
dprintk(1, "busy: streaming active\n");
return 1;
}
if (q->reading) {
dprintk(1, "busy: pending read #1\n");
return 1;
}
if (q->read_buf) {
dprintk(1, "busy: pending read #2\n");
return 1;
}
for (i = 0; i < VIDEO_MAX_FRAME; i++) {
if (NULL == q->bufs[i])
continue;
if (q->bufs[i]->map) {
dprintk(1, "busy: buffer #%d mapped\n", i);
return 1;
}
if (q->bufs[i]->state == VIDEOBUF_QUEUED) {
dprintk(1, "busy: buffer #%d queued\n", i);
return 1;
}
if (q->bufs[i]->state == VIDEOBUF_ACTIVE) {
dprintk(1, "busy: buffer #%d active\n", i);
return 1;
}
}
return 0;
}
EXPORT_SYMBOL_GPL(videobuf_queue_is_busy);
/*
* __videobuf_free() - free all the buffers and their control structures
*
* This function can only be called if streaming/reading is off, i.e. no buffers
* are under control of the driver.
*/
/* Locking: Caller holds q->vb_lock */
static int __videobuf_free(struct videobuf_queue *q)
{
int i;
dprintk(1, "%s\n", __func__);
if (!q)
return 0;
if (q->streaming || q->reading) {
dprintk(1, "Cannot free buffers when streaming or reading\n");
return -EBUSY;
}
MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
for (i = 0; i < VIDEO_MAX_FRAME; i++)
if (q->bufs[i] && q->bufs[i]->map) {
dprintk(1, "Cannot free mmapped buffers\n");
return -EBUSY;
}
for (i = 0; i < VIDEO_MAX_FRAME; i++) {
if (NULL == q->bufs[i])
continue;
q->ops->buf_release(q, q->bufs[i]);
kfree(q->bufs[i]);
q->bufs[i] = NULL;
}
return 0;
}
/* Locking: Caller holds q->vb_lock */
void videobuf_queue_cancel(struct videobuf_queue *q)
{
unsigned long flags = 0;
int i;
q->streaming = 0;
q->reading = 0;
wake_up_interruptible_sync(&q->wait);
/* remove queued buffers from list */
spin_lock_irqsave(q->irqlock, flags);
for (i = 0; i < VIDEO_MAX_FRAME; i++) {
if (NULL == q->bufs[i])
continue;
if (q->bufs[i]->state == VIDEOBUF_QUEUED) {
list_del(&q->bufs[i]->queue);
q->bufs[i]->state = VIDEOBUF_ERROR;
wake_up_all(&q->bufs[i]->done);
}
}
spin_unlock_irqrestore(q->irqlock, flags);
/* free all buffers + clear queue */
for (i = 0; i < VIDEO_MAX_FRAME; i++) {
if (NULL == q->bufs[i])
continue;
q->ops->buf_release(q, q->bufs[i]);
}
INIT_LIST_HEAD(&q->stream);
}
EXPORT_SYMBOL_GPL(videobuf_queue_cancel);
/* --------------------------------------------------------------------- */
/* Locking: Caller holds q->vb_lock */
enum v4l2_field videobuf_next_field(struct videobuf_queue *q)
{
enum v4l2_field field = q->field;
BUG_ON(V4L2_FIELD_ANY == field);
if (V4L2_FIELD_ALTERNATE == field) {
if (V4L2_FIELD_TOP == q->last) {
field = V4L2_FIELD_BOTTOM;
q->last = V4L2_FIELD_BOTTOM;
} else {
field = V4L2_FIELD_TOP;
q->last = V4L2_FIELD_TOP;
}
}
return field;
}
EXPORT_SYMBOL_GPL(videobuf_next_field);
static inline void ns_to_timeval32(struct __kernel_v4l2_timeval *tv, s64 nsec)
{
struct __kernel_old_timeval tv_old;
tv_old = ns_to_kernel_old_timeval(nsec);
tv->tv_sec = tv_old.tv_sec;
tv->tv_usec = tv_old.tv_sec / NSEC_PER_USEC;
}
/* Locking: Caller holds q->vb_lock */
static void videobuf_status(struct videobuf_queue *q, struct v4l2_buffer *b,
struct videobuf_buffer *vb, enum v4l2_buf_type type)
{
MAGIC_CHECK(vb->magic, MAGIC_BUFFER);
MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
b->index = vb->i;
b->type = type;
b->memory = vb->memory;
switch (b->memory) {
case V4L2_MEMORY_MMAP:
b->m.offset = vb->boff;
b->length = vb->bsize;
break;
case V4L2_MEMORY_USERPTR:
b->m.userptr = vb->baddr;
b->length = vb->bsize;
break;
case V4L2_MEMORY_OVERLAY:
b->m.offset = vb->boff;
break;
case V4L2_MEMORY_DMABUF:
/* DMABUF is not handled in videobuf framework */
break;
}
b->flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
if (vb->map)
b->flags |= V4L2_BUF_FLAG_MAPPED;
switch (vb->state) {
case VIDEOBUF_PREPARED:
case VIDEOBUF_QUEUED:
case VIDEOBUF_ACTIVE:
b->flags |= V4L2_BUF_FLAG_QUEUED;
break;
case VIDEOBUF_ERROR:
b->flags |= V4L2_BUF_FLAG_ERROR;
/* fall through */
case VIDEOBUF_DONE:
b->flags |= V4L2_BUF_FLAG_DONE;
break;
case VIDEOBUF_NEEDS_INIT:
case VIDEOBUF_IDLE:
/* nothing */
break;
}
b->field = vb->field;
//b->timestamp = ns_to_kernel_old_timeval(vb->ts);
ns_to_timeval32(&b->timestamp, vb->ts);
b->bytesused = vb->size;
b->sequence = vb->field_count >> 1;
}
int videobuf_mmap_free(struct videobuf_queue *q)
{
int ret;
videobuf_queue_lock(q);
ret = __videobuf_free(q);
videobuf_queue_unlock(q);
return ret;
}
EXPORT_SYMBOL_GPL(videobuf_mmap_free);
/* Locking: Caller holds q->vb_lock */
int __videobuf_mmap_setup(struct videobuf_queue *q,
unsigned int bcount, unsigned int bsize,
enum v4l2_memory memory)
{
unsigned int i;
int err;
MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
err = __videobuf_free(q);
if (0 != err)
return err;
/* Allocate and initialize buffers */
for (i = 0; i < bcount; i++) {
q->bufs[i] = videobuf_alloc_vb(q);
if (NULL == q->bufs[i])
break;
q->bufs[i]->i = i;
q->bufs[i]->memory = memory;
q->bufs[i]->bsize = bsize;
switch (memory) {
case V4L2_MEMORY_MMAP:
q->bufs[i]->boff = PAGE_ALIGN(bsize) * i;
break;
case V4L2_MEMORY_USERPTR:
case V4L2_MEMORY_OVERLAY:
case V4L2_MEMORY_DMABUF:
/* nothing */
break;
}
}
if (!i)
return -ENOMEM;
dprintk(1, "mmap setup: %d buffers, %d bytes each\n", i, bsize);
return i;
}
EXPORT_SYMBOL_GPL(__videobuf_mmap_setup);
int videobuf_mmap_setup(struct videobuf_queue *q,
unsigned int bcount, unsigned int bsize,
enum v4l2_memory memory)
{
int ret;
videobuf_queue_lock(q);
ret = __videobuf_mmap_setup(q, bcount, bsize, memory);
videobuf_queue_unlock(q);
return ret;
}
EXPORT_SYMBOL_GPL(videobuf_mmap_setup);
int videobuf_reqbufs(struct videobuf_queue *q,
struct v4l2_requestbuffers *req)
{
unsigned int size, count;
int retval;
if (req->memory != V4L2_MEMORY_MMAP &&
req->memory != V4L2_MEMORY_USERPTR &&
req->memory != V4L2_MEMORY_OVERLAY) {
dprintk(1, "reqbufs: memory type invalid\n");
return -EINVAL;
}
videobuf_queue_lock(q);
if (req->type != q->type) {
dprintk(1, "reqbufs: queue type invalid\n");
retval = -EINVAL;
goto done;
}
if (q->streaming) {
dprintk(1, "reqbufs: streaming already exists\n");
retval = -EBUSY;
goto done;
}
if (!list_empty(&q->stream)) {
dprintk(1, "reqbufs: stream running\n");
retval = -EBUSY;
goto done;
}
if (req->count == 0) {
dprintk(1, "reqbufs: count invalid (%d)\n", req->count);
retval = __videobuf_free(q);
goto done;
}
count = req->count;
if (count > VIDEO_MAX_FRAME)
count = VIDEO_MAX_FRAME;
size = 0;
q->ops->buf_setup(q, &count, &size);
dprintk(1, "reqbufs: bufs=%d, size=0x%x [%u pages total]\n",
count, size,
(unsigned int)((count * PAGE_ALIGN(size)) >> PAGE_SHIFT));
retval = __videobuf_mmap_setup(q, count, size, req->memory);
if (retval < 0) {
dprintk(1, "reqbufs: mmap setup returned %d\n", retval);
goto done;
}
req->count = retval;
retval = 0;
done:
videobuf_queue_unlock(q);
return retval;
}
EXPORT_SYMBOL_GPL(videobuf_reqbufs);
int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b)
{
int ret = -EINVAL;
videobuf_queue_lock(q);
if (unlikely(b->type != q->type)) {
dprintk(1, "querybuf: Wrong type.\n");
goto done;
}
if (unlikely(b->index >= VIDEO_MAX_FRAME)) {
dprintk(1, "querybuf: index out of range.\n");
goto done;
}
if (unlikely(NULL == q->bufs[b->index])) {
dprintk(1, "querybuf: buffer is null.\n");
goto done;
}
videobuf_status(q, b, q->bufs[b->index], q->type);
ret = 0;
done:
videobuf_queue_unlock(q);
return ret;
}
EXPORT_SYMBOL_GPL(videobuf_querybuf);
static __u64 v4l2_timeval_to_ns_local(const struct __kernel_v4l2_timeval *tv)
{
return (__u64)tv->tv_sec * 1000000000ULL + tv->tv_usec * 1000;
}
int videobuf_qbuf(struct videobuf_queue *q, struct v4l2_buffer *b)
{
struct videobuf_buffer *buf;
enum v4l2_field field;
unsigned long flags = 0;
int retval;
MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
if (b->memory == V4L2_MEMORY_MMAP)
mmap_read_lock(current->mm);
videobuf_queue_lock(q);
retval = -EBUSY;
if (q->reading) {
dprintk(1, "qbuf: Reading running...\n");
goto done;
}
retval = -EINVAL;
if (b->type != q->type) {
dprintk(1, "qbuf: Wrong type.\n");
goto done;
}
if (b->index >= VIDEO_MAX_FRAME) {
dprintk(1, "qbuf: index out of range.\n");
goto done;
}
buf = q->bufs[b->index];
if (NULL == buf) {
dprintk(1, "qbuf: buffer is null.\n");
goto done;
}
MAGIC_CHECK(buf->magic, MAGIC_BUFFER);
if (buf->memory != b->memory) {
dprintk(1, "qbuf: memory type is wrong.\n");
goto done;
}
if (buf->state != VIDEOBUF_NEEDS_INIT && buf->state != VIDEOBUF_IDLE) {
dprintk(1, "qbuf: buffer is already queued or active.\n");
goto done;
}
switch (b->memory) {
case V4L2_MEMORY_MMAP:
if (0 == buf->baddr) {
dprintk(1, "qbuf: mmap requested but buffer addr is zero!\n");
goto done;
}
if (q->type == V4L2_BUF_TYPE_VIDEO_OUTPUT
|| q->type == V4L2_BUF_TYPE_VBI_OUTPUT
|| q->type == V4L2_BUF_TYPE_SLICED_VBI_OUTPUT
|| q->type == V4L2_BUF_TYPE_SDR_OUTPUT) {
buf->size = b->bytesused;
buf->field = b->field;
buf->ts = v4l2_timeval_to_ns_local(&b->timestamp);
}
break;
case V4L2_MEMORY_USERPTR:
if (b->length < buf->bsize) {
dprintk(1, "qbuf: buffer length is not enough\n");
goto done;
}
if (VIDEOBUF_NEEDS_INIT != buf->state &&
buf->baddr != b->m.userptr)
q->ops->buf_release(q, buf);
buf->baddr = b->m.userptr;
break;
case V4L2_MEMORY_OVERLAY:
buf->boff = b->m.offset;
break;
default:
dprintk(1, "qbuf: wrong memory type\n");
goto done;
}
dprintk(1, "qbuf: requesting next field\n");
field = videobuf_next_field(q);
retval = q->ops->buf_prepare(q, buf, field);
if (0 != retval) {
dprintk(1, "qbuf: buffer_prepare returned %d\n", retval);
goto done;
}
list_add_tail(&buf->stream, &q->stream);
if (q->streaming) {
spin_lock_irqsave(q->irqlock, flags);
q->ops->buf_queue(q, buf);
spin_unlock_irqrestore(q->irqlock, flags);
}
dprintk(1, "qbuf: succeeded\n");
retval = 0;
wake_up_interruptible_sync(&q->wait);
done:
videobuf_queue_unlock(q);
if (b->memory == V4L2_MEMORY_MMAP)
mmap_read_unlock(current->mm);
return retval;
}
EXPORT_SYMBOL_GPL(videobuf_qbuf);
/* Locking: Caller holds q->vb_lock */
static int stream_next_buffer_check_queue(struct videobuf_queue *q, int noblock)
{
int retval;
checks:
if (!q->streaming) {
dprintk(1, "next_buffer: Not streaming\n");
retval = -EINVAL;
goto done;
}
if (list_empty(&q->stream)) {
if (noblock) {
retval = -EAGAIN;
dprintk(2, "next_buffer: no buffers to dequeue\n");
goto done;
} else {
dprintk(2, "next_buffer: waiting on buffer\n");
/* Drop lock to avoid deadlock with qbuf */
videobuf_queue_unlock(q);
/* Checking list_empty and streaming is safe without
* locks because we goto checks to validate while
* holding locks before proceeding */
retval = wait_event_interruptible(q->wait,
!list_empty(&q->stream) || !q->streaming);
videobuf_queue_lock(q);
if (retval)
goto done;
goto checks;
}
}
retval = 0;
done:
return retval;
}
/* Locking: Caller holds q->vb_lock */
static int stream_next_buffer(struct videobuf_queue *q,
struct videobuf_buffer **vb, int nonblocking)
{
int retval;
struct videobuf_buffer *buf = NULL;
retval = stream_next_buffer_check_queue(q, nonblocking);
if (retval)
goto done;
buf = list_entry(q->stream.next, struct videobuf_buffer, stream);
retval = videobuf_waiton(q, buf, nonblocking, 1);
if (retval < 0)
goto done;
*vb = buf;
done:
return retval;
}
int videobuf_dqbuf(struct videobuf_queue *q,
struct v4l2_buffer *b, int nonblocking)
{
struct videobuf_buffer *buf = NULL;
int retval;
MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
memset(b, 0, sizeof(*b));
videobuf_queue_lock(q);
retval = stream_next_buffer(q, &buf, nonblocking);
if (retval < 0) {
dprintk(1, "dqbuf: next_buffer error: %i\n", retval);
goto done;
}
switch (buf->state) {
case VIDEOBUF_ERROR:
dprintk(1, "dqbuf: state is error\n");
break;
case VIDEOBUF_DONE:
dprintk(1, "dqbuf: state is done\n");
break;
default:
dprintk(1, "dqbuf: state invalid\n");
retval = -EINVAL;
goto done;
}
CALL(q, sync, q, buf);
videobuf_status(q, b, buf, q->type);
list_del(&buf->stream);
buf->state = VIDEOBUF_IDLE;
b->flags &= ~V4L2_BUF_FLAG_DONE;
done:
videobuf_queue_unlock(q);
return retval;
}
EXPORT_SYMBOL_GPL(videobuf_dqbuf);
int videobuf_streamon(struct videobuf_queue *q)
{
struct videobuf_buffer *buf;
unsigned long flags = 0;
int retval;
videobuf_queue_lock(q);
retval = -EBUSY;
if (q->reading)
goto done;
retval = 0;
if (q->streaming)
goto done;
q->streaming = 1;
spin_lock_irqsave(q->irqlock, flags);
list_for_each_entry(buf, &q->stream, stream)
if (buf->state == VIDEOBUF_PREPARED)
q->ops->buf_queue(q, buf);
spin_unlock_irqrestore(q->irqlock, flags);
wake_up_interruptible_sync(&q->wait);
done:
videobuf_queue_unlock(q);
return retval;
}
EXPORT_SYMBOL_GPL(videobuf_streamon);
/* Locking: Caller holds q->vb_lock */
static int __videobuf_streamoff(struct videobuf_queue *q)
{
if (!q->streaming)
return -EINVAL;
videobuf_queue_cancel(q);
return 0;
}
int videobuf_streamoff(struct videobuf_queue *q)
{
int retval;
videobuf_queue_lock(q);
retval = __videobuf_streamoff(q);
videobuf_queue_unlock(q);
return retval;
}
EXPORT_SYMBOL_GPL(videobuf_streamoff);
/* Locking: Caller holds q->vb_lock */
static ssize_t videobuf_read_zerocopy(struct videobuf_queue *q,
char __user *data,
size_t count, loff_t *ppos)
{
enum v4l2_field field;
unsigned long flags = 0;
int retval;
MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
/* setup stuff */
q->read_buf = videobuf_alloc_vb(q);
if (NULL == q->read_buf)
return -ENOMEM;
q->read_buf->memory = V4L2_MEMORY_USERPTR;
q->read_buf->baddr = (unsigned long)data;
q->read_buf->bsize = count;
field = videobuf_next_field(q);
retval = q->ops->buf_prepare(q, q->read_buf, field);
if (0 != retval)
goto done;
/* start capture & wait */
spin_lock_irqsave(q->irqlock, flags);
q->ops->buf_queue(q, q->read_buf);
spin_unlock_irqrestore(q->irqlock, flags);
retval = videobuf_waiton(q, q->read_buf, 0, 0);
if (0 == retval) {
CALL(q, sync, q, q->read_buf);
if (VIDEOBUF_ERROR == q->read_buf->state)
retval = -EIO;
else
retval = q->read_buf->size;
}
done:
/* cleanup */
q->ops->buf_release(q, q->read_buf);
kfree(q->read_buf);
q->read_buf = NULL;
return retval;
}
static int __videobuf_copy_to_user(struct videobuf_queue *q,
struct videobuf_buffer *buf,
char __user *data, size_t count,
int nonblocking)
{
void *vaddr = CALLPTR(q, vaddr, buf);
/* copy to userspace */
if (count > buf->size - q->read_off)
count = buf->size - q->read_off;
if (copy_to_user(data, vaddr + q->read_off, count))
return -EFAULT;
return count;
}
static int __videobuf_copy_stream(struct videobuf_queue *q,
struct videobuf_buffer *buf,
char __user *data, size_t count, size_t pos,
int vbihack, int nonblocking)
{
unsigned int *fc = CALLPTR(q, vaddr, buf);
if (vbihack) {
/* dirty, undocumented hack -- pass the frame counter
* within the last four bytes of each vbi data block.
* We need that one to maintain backward compatibility
* to all vbi decoding software out there ... */
fc += (buf->size >> 2) - 1;
*fc = buf->field_count >> 1;
dprintk(1, "vbihack: %d\n", *fc);
}
/* copy stuff using the common method */
count = __videobuf_copy_to_user(q, buf, data, count, nonblocking);
if ((count == -EFAULT) && (pos == 0))
return -EFAULT;
return count;
}
ssize_t videobuf_read_one(struct videobuf_queue *q,
char __user *data, size_t count, loff_t *ppos,
int nonblocking)
{
enum v4l2_field field;
unsigned long flags = 0;
unsigned size = 0, nbufs = 1;
int retval;
MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
videobuf_queue_lock(q);
q->ops->buf_setup(q, &nbufs, &size);
if (NULL == q->read_buf &&
count >= size &&
!nonblocking) {
retval = videobuf_read_zerocopy(q, data, count, ppos);
if (retval >= 0 || retval == -EIO)
/* ok, all done */
goto done;
/* fallback to kernel bounce buffer on failures */
}
if (NULL == q->read_buf) {
/* need to capture a new frame */
retval = -ENOMEM;
q->read_buf = videobuf_alloc_vb(q);
dprintk(1, "video alloc=0x%p\n", q->read_buf);
if (NULL == q->read_buf)
goto done;
q->read_buf->memory = V4L2_MEMORY_USERPTR;
q->read_buf->bsize = count; /* preferred size */
field = videobuf_next_field(q);
retval = q->ops->buf_prepare(q, q->read_buf, field);
if (0 != retval) {
kfree(q->read_buf);
q->read_buf = NULL;
goto done;
}
spin_lock_irqsave(q->irqlock, flags);
q->ops->buf_queue(q, q->read_buf);
spin_unlock_irqrestore(q->irqlock, flags);
q->read_off = 0;
}
/* wait until capture is done */
retval = videobuf_waiton(q, q->read_buf, nonblocking, 1);
if (0 != retval)
goto done;
CALL(q, sync, q, q->read_buf);
if (VIDEOBUF_ERROR == q->read_buf->state) {
/* catch I/O errors */
q->ops->buf_release(q, q->read_buf);
kfree(q->read_buf);
q->read_buf = NULL;
retval = -EIO;
goto done;
}
/* Copy to userspace */
retval = __videobuf_copy_to_user(q, q->read_buf, data, count, nonblocking);
if (retval < 0)
goto done;
q->read_off += retval;
if (q->read_off == q->read_buf->size) {
/* all data copied, cleanup */
q->ops->buf_release(q, q->read_buf);
kfree(q->read_buf);
q->read_buf = NULL;
}
done:
videobuf_queue_unlock(q);
return retval;
}
EXPORT_SYMBOL_GPL(videobuf_read_one);
/* Locking: Caller holds q->vb_lock */
static int __videobuf_read_start(struct videobuf_queue *q)
{
enum v4l2_field field;
unsigned long flags = 0;
unsigned int count = 0, size = 0;
int err, i;
q->ops->buf_setup(q, &count, &size);
if (count < 2)
count = 2;
if (count > VIDEO_MAX_FRAME)
count = VIDEO_MAX_FRAME;
size = PAGE_ALIGN(size);
err = __videobuf_mmap_setup(q, count, size, V4L2_MEMORY_USERPTR);
if (err < 0)
return err;
count = err;
for (i = 0; i < count; i++) {
field = videobuf_next_field(q);
err = q->ops->buf_prepare(q, q->bufs[i], field);
if (err)
return err;
list_add_tail(&q->bufs[i]->stream, &q->stream);
}