/**
* vb2_reqbufs() - Initiate streaming
* @q: videobuf2 queue
* @req: struct passed from userspace to vidioc_reqbufs handler in driver
*
* Should be called from vidioc_reqbufs ioctl handler of a driver.
* This function:
* 1) verifies streaming parameters passed from the userspace,
* 2) sets up the queue,
* 3) negotiates number of buffers and planes per buffer with the driver
* to be used during streaming,
* 4) allocates internal buffer structures (struct vb2_buffer), according to
* the agreed parameters,
* 5) for MMAP memory type, allocates actual video memory, using the
* memory handling/allocation routines provided during queue initialization
*
* If req->count is 0, all the memory will be freed instead.
* If the queue has been allocated previously (by a previous vb2_reqbufs) call
* and the queue is not busy, memory will be reallocated.
*
* The return values from this function are intended to be directly returned
* from vidioc_reqbufs handler in driver.
*/
int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
{
unsigned int num_buffers = 0;
unsigned int num_planes = 0;
unsigned long plane_sizes[VIDEO_MAX_PLANES];
int ret = 0;
if (q->fileio) {
dprintk(1, "reqbufs: file io in progress\n");
return -EBUSY;
}
if (req->memory != V4L2_MEMORY_MMAP
&& req->memory != V4L2_MEMORY_USERPTR) {
dprintk(1, "reqbufs: unsupported memory type\n");
return -EINVAL;
}
if (req->type != q->type) {
dprintk(1, "reqbufs: requested type is incorrect\n");
return -EINVAL;
}
if (q->streaming) {
dprintk(1, "reqbufs: streaming active\n");
return -EBUSY;
}
/*
* Make sure all the required memory ops for given memory type
* are available.
*/
if (req->memory == V4L2_MEMORY_MMAP && __verify_mmap_ops(q)) {
dprintk(1, "reqbufs: MMAP for current setup unsupported\n");
return -EINVAL;
}
if (req->memory == V4L2_MEMORY_USERPTR && __verify_userptr_ops(q)) {
dprintk(1, "reqbufs: USERPTR for current setup unsupported\n");
return -EINVAL;
}
if (req->count == 0 || q->num_buffers != 0 || q->memory != req->memory) {
/*
* We already have buffers allocated, so first check if they
* are not in use and can be freed.
*/
if (q->memory == V4L2_MEMORY_MMAP && __buffers_in_use(q)) {
dprintk(1, "reqbufs: memory in use, cannot free\n");
return -EBUSY;
}
__vb2_queue_free(q);
/*
* In case of REQBUFS(0) return immediately without calling
* driver's queue_setup() callback and allocating resources.
*/
if (req->count == 0)
return 0;
}
/*
* Make sure the requested values and current defaults are sane.
*/
num_buffers = min_t(unsigned int, req->count, VIDEO_MAX_FRAME);
memset(plane_sizes, 0, sizeof(plane_sizes));
memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx));
q->memory = req->memory;
/*
* Ask the driver how many buffers and planes per buffer it requires.
* Driver also sets the size and allocator context for each plane.
*/
ret = call_qop(q, queue_setup, q, &num_buffers, &num_planes,
plane_sizes, q->alloc_ctx);
if (ret)
return ret;
/* Finally, allocate buffers and video memory */
ret = __vb2_queue_alloc(q, req->memory, num_buffers, num_planes,
plane_sizes);
if (ret == 0) {
dprintk(1, "Memory allocation failed\n");
return -ENOMEM;
}
/*
* Check if driver can handle the allocated number of buffers.
*/
if (ret < num_buffers) {
unsigned int orig_num_buffers;
orig_num_buffers = num_buffers = ret;
ret = call_qop(q, queue_setup, q, &num_buffers, &num_planes,
plane_sizes, q->alloc_ctx);
if (ret)
goto free_mem;
if (orig_num_buffers < num_buffers) {
ret = -ENOMEM;
goto free_mem;
}
/*
* Ok, driver accepted smaller number of buffers.
*/
ret = num_buffers;
}
/*
* Return the number of successfully allocated buffers
* to the userspace.
*/
req->count = ret;
return 0;
free_mem:
__vb2_queue_free(q);
return ret;
}
int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
{
unsigned int num_buffers, num_planes;
unsigned long plane_sizes[VIDEO_MAX_PLANES];
int ret = 0;
num_buffers = 0;
num_planes = 0;
if (q->fileio) {
dprintk(1, "reqbufs: file io in progress\n");
return -EBUSY;
}
if (req->memory != V4L2_MEMORY_MMAP
&& req->memory != V4L2_MEMORY_USERPTR) {
dprintk(1, "reqbufs: unsupported memory type\n");
return -EINVAL;
}
if (req->type != q->type) {
dprintk(1, "reqbufs: requested type is incorrect\n");
return -EINVAL;
}
if (q->streaming) {
dprintk(1, "reqbufs: streaming active\n");
return -EBUSY;
}
if (req->memory == V4L2_MEMORY_MMAP && __verify_mmap_ops(q)) {
dprintk(1, "reqbufs: MMAP for current setup unsupported\n");
return -EINVAL;
}
if (req->memory == V4L2_MEMORY_USERPTR && __verify_userptr_ops(q)) {
dprintk(1, "reqbufs: USERPTR for current setup unsupported\n");
return -EINVAL;
}
if (q->memory == req->memory && req->count == q->num_buffers)
return 0;
if (req->count == 0 || q->num_buffers != 0 || q->memory != req->memory) {
if (q->memory == V4L2_MEMORY_MMAP && __buffers_in_use(q)) {
dprintk(1, "reqbufs: memory in use, cannot free\n");
return -EBUSY;
}
__vb2_queue_free(q);
if (req->count == 0)
return 0;
}
num_buffers = min_t(unsigned int, req->count, VIDEO_MAX_FRAME);
memset(plane_sizes, 0, sizeof(plane_sizes));
memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx));
q->memory = req->memory;
ret = call_qop(q, queue_setup, q, NULL, &num_buffers,
&num_planes, q->plane_sizes, q->alloc_ctx);
if (ret)
return ret;
ret = __vb2_queue_alloc(q, req->memory, num_buffers, num_planes,
plane_sizes);
if (ret == 0) {
dprintk(1, "Memory allocation failed\n");
return -ENOMEM;
}
if (ret < num_buffers) {
unsigned int orig_num_buffers;
orig_num_buffers = num_buffers = ret;
ret = call_qop(q, queue_setup, q, NULL, &num_buffers,
&num_planes, q->plane_sizes, q->alloc_ctx);
if (ret)
goto free_mem;
if (orig_num_buffers < num_buffers) {
ret = -ENOMEM;
goto free_mem;
}
ret = num_buffers;
}
req->count = ret;
return 0;
free_mem:
__vb2_queue_free(q);
return ret;
}