Hi Pawel
On Sun, 3 Apr 2011, Pawel Osciak wrote:
> 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?
Don't think so - it's a bogus request...
> > /* 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.
Yes, there are issues... I think, we can just return -EBUSY on such
fragmenting DESTROY calls. Anything left over will be freed on last
close() anyway. Let's decide how we want to handle these and I'll prepare
a v2, probably with documentation this time:-)
> > +/**
> > + * __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?
It was deliberate, yes, but it seems wrong to me now too... I'll re-think
and probably remove it.
> > + /*
> > + * 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?
Right, thanks for catching.
> > + 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...
Ok, will have a look at these.
>
> > * @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
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-media" in
> > the body of a message to majordomo@xxxxxxxxxxxxxxx
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> >
>
> --
> Best regards,
> Pawel Osciak
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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