/* 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;
}
/* 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]->input = UNSET;
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;
}
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;
}
