Hi Gueannadi,
A preliminary quick scan over the patch while waiting for documentation.
On Fri, Apr 1, 2011 at 07:06, Guennadi Liakhovetski
<g.liakhovetski@xxxxxx> wrote:
> This patch extends the videobuf2 framework with new helper functions and
> modifies existing ones to support multi-size video-buffers.
>
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> ---
>
> v2: fix offset calculation in __setup_offsets()
>
> drivers/media/video/videobuf2-core.c | 195 ++++++++++++++++++++++++++++++----
> include/media/videobuf2-core.h | 15 +++
> 2 files changed, 187 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/media/video/videobuf2-core.c b/drivers/media/video/videobuf2-core.c
> index 71734a4..20e1572 100644
> --- a/drivers/media/video/videobuf2-core.c
> +++ b/drivers/media/video/videobuf2-core.c
> @@ -41,7 +41,7 @@ module_param(debug, int, 0644);
> * __vb2_buf_mem_alloc() - allocate video memory for the given buffer
> */
> static int __vb2_buf_mem_alloc(struct vb2_buffer *vb,
> - unsigned long *plane_sizes)
> + const unsigned long *plane_sizes)
> {
> struct vb2_queue *q = vb->vb2_queue;
> void *mem_priv;
> @@ -107,13 +107,22 @@ static void __vb2_buf_userptr_put(struct vb2_buffer *vb)
> * __setup_offsets() - setup unique offsets ("cookies") for every plane in
> * every buffer on the queue
> */
> -static void __setup_offsets(struct vb2_queue *q)
> +static void __setup_offsets(struct vb2_queue *q, unsigned int n)
> {
> unsigned int buffer, plane;
> struct vb2_buffer *vb;
> - unsigned long off = 0;
> + unsigned long off;
>
> - for (buffer = 0; buffer < q->num_buffers; ++buffer) {
> + if (q->num_buffers) {
> + struct v4l2_plane *p;
> + vb = q->bufs[q->num_buffers - 1];
> + p = &vb->v4l2_planes[vb->num_planes - 1];
> + off = PAGE_ALIGN(p->m.mem_offset + p->length);
> + } else {
> + off = 0;
> + }
> +
> + for (buffer = q->num_buffers - n; buffer < q->num_buffers; ++buffer) {
> vb = q->bufs[buffer];
> if (!vb)
> continue;
> @@ -139,7 +148,7 @@ static void __setup_offsets(struct vb2_queue *q)
> */
> static int __vb2_queue_alloc(struct vb2_queue *q, enum v4l2_memory memory,
> unsigned int num_buffers, unsigned int num_planes,
> - unsigned long plane_sizes[])
> + const unsigned long plane_sizes[])
> {
> unsigned int buffer;
> struct vb2_buffer *vb;
> @@ -160,7 +169,7 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum v4l2_memory memory,
> vb->state = VB2_BUF_STATE_DEQUEUED;
> vb->vb2_queue = q;
> vb->num_planes = num_planes;
> - vb->v4l2_buf.index = buffer;
> + vb->v4l2_buf.index = q->num_buffers + buffer;
> vb->v4l2_buf.type = q->type;
> vb->v4l2_buf.memory = memory;
>
> @@ -188,12 +197,12 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum v4l2_memory memory,
> }
> }
>
> - q->bufs[buffer] = vb;
> + q->bufs[q->num_buffers + buffer] = vb;
> }
>
> - q->num_buffers = buffer;
> + q->num_buffers += buffer;
>
> - __setup_offsets(q);
> + __setup_offsets(q, buffer);
>
> dprintk(1, "Allocated %d buffers, %d plane(s) each\n",
> q->num_buffers, num_planes);
> @@ -204,12 +213,13 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum v4l2_memory memory,
> /**
> * __vb2_free_mem() - release all video buffer memory for a given queue
> */
> -static void __vb2_free_mem(struct vb2_queue *q)
> +static void __vb2_free_mem(struct vb2_queue *q, struct v4l2_buffer_span *span)
> {
> unsigned int buffer;
> struct vb2_buffer *vb;
>
> - for (buffer = 0; buffer < q->num_buffers; ++buffer) {
> + for (buffer = span->index; buffer < span->index + span->count;
> + ++buffer) {
> vb = q->bufs[buffer];
> if (!vb)
> continue;
> @@ -222,18 +232,17 @@ static void __vb2_free_mem(struct vb2_queue *q)
> }
> }
>
> -/**
> - * __vb2_queue_free() - free the queue - video memory and related information
> - * and return the queue to an uninitialized state. Might be called even if the
> - * queue has already been freed.
> - */
> -static void __vb2_queue_free(struct vb2_queue *q)
> +int vb2_destroy_bufs(struct vb2_queue *q, struct v4l2_buffer_span *span)
> {
> - unsigned int buffer;
> + int buffer;
> +
> + if (span->index + span->count > q->num_buffers)
> + return -EINVAL;
>
Maybe it'd be better to free what we can here?
> /* Call driver-provided cleanup function for each buffer, if provided */
> if (q->ops->buf_cleanup) {
> - for (buffer = 0; buffer < q->num_buffers; ++buffer) {
> + for (buffer = span->index;
> + buffer < span->index + span->count; ++buffer) {
> if (NULL == q->bufs[buffer])
> continue;
> q->ops->buf_cleanup(q->bufs[buffer]);
> @@ -241,16 +250,36 @@ static void __vb2_queue_free(struct vb2_queue *q)
> }
>
> /* Release video buffer memory */
> - __vb2_free_mem(q);
> + __vb2_free_mem(q, span);
>
> /* Free videobuf buffers */
> - for (buffer = 0; buffer < q->num_buffers; ++buffer) {
> + for (buffer = span->index;
> + buffer < span->index + span->count; ++buffer) {
> kfree(q->bufs[buffer]);
> q->bufs[buffer] = NULL;
> }
>
> - q->num_buffers = 0;
> - q->memory = 0;
> + q->num_buffers -= span->count;
> + if (!q->num_buffers)
> + q->memory = 0;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(vb2_destroy_bufs);
> +
This messes up q->num_buffers, which is used in other places as the
upper bound for indexes and assumes <0; q->num_buffers> is contiguous.
Examples include querybufs, buffers_in_use. In general, I find it
unnecessary complicated and dangerous to allow introducing "holes" in
buffer indexes.
> +/**
> + * __vb2_queue_free() - free the queue - video memory and related information
> + * and return the queue to an uninitialized state. Might be called even if the
> + * queue has already been freed.
> + */
> +static void __vb2_queue_free(struct vb2_queue *q)
> +{
> + struct v4l2_buffer_span span = {
> + .index = 0,
> + .count = q->num_buffers,
> + };
> +
> + vb2_destroy_bufs(q, &span);
> }
>
> /**
> @@ -576,6 +605,126 @@ free_mem:
> }
> EXPORT_SYMBOL_GPL(vb2_reqbufs);
>
> +int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
> +{
> + unsigned int num_planes, num_buffers = 0;
> + unsigned long plane_sizes[VIDEO_MAX_PLANES] = {create->size};
> + int ret = 0;
> +
> + if (q->fileio) {
> + dprintk(1, "%s(): file io in progress\n", __func__);
> + return -EBUSY;
> + }
> +
> + if (create->memory != V4L2_MEMORY_MMAP
> + && create->memory != V4L2_MEMORY_USERPTR) {
> + dprintk(1, "%s(): unsupported memory type\n", __func__);
> + return -EINVAL;
> + }
> +
> + if (create->format.type != q->type) {
> + dprintk(1, "%s(): requested type is incorrect\n", __func__);
> + return -EINVAL;
> + }
> +
> + /*
> + * Make sure all the required memory ops for given memory type
> + * are available.
> + */
> + if (create->memory == V4L2_MEMORY_MMAP && __verify_mmap_ops(q)) {
> + dprintk(1, "%s(): MMAP for current setup unsupported\n", __func__);
> + return -EINVAL;
> + }
> +
> + if (create->memory == V4L2_MEMORY_USERPTR && __verify_userptr_ops(q)) {
> + dprintk(1, "%s(): USERPTR for current setup unsupported\n", __func__);
> + return -EINVAL;
> + }
> +
> + if (q->num_buffers == VIDEO_MAX_FRAME) {
> + dprintk(1, "%s(): maximum number of buffers already allocated\n",
> + __func__);
> + return -ENOBUFS;
> + }
> +
> + create->index = q->num_buffers + 1;
> +
Is this gap in indexes deliberate?
> + /*
> + * Make sure the requested values and current defaults are sane.
> + */
> + create->count = min_t(unsigned int, create->count, VIDEO_MAX_FRAME - q->num_buffers);
> +
> + if (!q->num_buffers)
> + memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx));
> +
> + /*
> + * 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_add, q, create, &num_buffers, &num_planes,
> + plane_sizes, q->alloc_ctx);
> + if (ret)
> + return ret;
> +
> + /* Finally, allocate buffers and video memory */
> + ret = __vb2_queue_alloc(q, create->memory, num_buffers, num_planes,
> + plane_sizes);
> + if (ret < 0) {
> + dprintk(1, "Memory allocation failed with error: %d\n", ret);
> + return ret;
> + }
> +
> + /*
> + * Check if driver can handle the so far allocated number of buffers.
> + */
> + if (ret < num_buffers) {
> + unsigned int orig_num_buffers;
> +
> + create->count = ret;
> + orig_num_buffers = ret;
> +
> + /*
> + * num_buffers still contains the number of buffers, that the
> + * queue driver has allocated
> + */
> + ret = call_qop(q, queue_add, q, create, &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.
> + */
> + create->count = ret;
> +
> + q->memory = create->memory;
> +
> + return 0;
> +
> +free_mem:
> + __vb2_queue_free(q);
Are we freeing the whole queue on a failed CREATE? Shouldn't we only
be freeing the buffers that CREATE requested?
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(vb2_create_bufs);
> +
> +int vb2_submit_buf(struct vb2_queue *q, unsigned int idx)
> +{
> + return call_qop(q, buf_submit, q->bufs[idx]);
> +}
> +EXPORT_SYMBOL_GPL(vb2_submit_buf);
> +
> /**
> * vb2_plane_vaddr() - Return a kernel virtual address of a given plane
> * @vb: vb2_buffer to which the plane in question belongs to
> diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
> index f87472a..88076fc 100644
> --- a/include/media/videobuf2-core.h
> +++ b/include/media/videobuf2-core.h
I'll be adding more detailed documentation of vb2_ops soon as well.
Some comments in spirit of that change:
> @@ -177,6 +177,10 @@ struct vb2_buffer {
> * plane should be set in the sizes[] array and optional
> * per-plane allocator specific context in alloc_ctxs[]
> * array
> + * @queue_add: like above, but called from VIDIOC_CREATE_BUFS, but if
> + * there are already buffers on the queue, it won't replace
> + * them, but add new ones, possibly with a different format
> + * and plane sizes
Needs some info how the driver can react and what to return.
> * @wait_prepare: release any locks taken while calling vb2 functions;
> * it is called before an ioctl needs to wait for a new
> * buffer to arrive; required to avoid a deadlock in
> @@ -194,6 +198,8 @@ struct vb2_buffer {
> * each hardware operation in this callback;
> * if an error is returned, the buffer will not be queued
> * in driver; optional
> + * @buf_submit: called primarily to invalidate buffer caches for faster
> + * consequent queuing; optional
Ditto. Also, I think it needs a more detailed explanation...
> * @buf_finish: called before every dequeue of the buffer back to
> * userspace; drivers may perform any operations required
> * before userspace accesses the buffer; optional
> @@ -213,11 +219,16 @@ struct vb2_ops {
> int (*queue_setup)(struct vb2_queue *q, unsigned int *num_buffers,
> unsigned int *num_planes, unsigned long sizes[],
> void *alloc_ctxs[]);
> + int (*queue_add)(struct vb2_queue *q,
> + struct v4l2_create_buffers *create,
> + unsigned int *num_buffers, unsigned int *num_planes,
> + unsigned long sizes[], void *alloc_ctxs[]);
>
> void (*wait_prepare)(struct vb2_queue *q);
> void (*wait_finish)(struct vb2_queue *q);
>
> int (*buf_init)(struct vb2_buffer *vb);
> + int (*buf_submit)(struct vb2_buffer *vb);
> int (*buf_prepare)(struct vb2_buffer *vb);
> int (*buf_finish)(struct vb2_buffer *vb);
> void (*buf_cleanup)(struct vb2_buffer *vb);
> @@ -291,6 +302,10 @@ int vb2_wait_for_all_buffers(struct vb2_queue *q);
> int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b);
> int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req);
>
> +int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create);
> +int vb2_destroy_bufs(struct vb2_queue *q, struct v4l2_buffer_span *span);
> +int vb2_submit_buf(struct vb2_queue *q, unsigned int idx);
> +
> int vb2_queue_init(struct vb2_queue *q);
>
> void vb2_queue_release(struct vb2_queue *q);
> --
> 1.7.2.5
>
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--
Best regards,
Pawel Osciak
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