diff options
author | Benjamin Gaignard <benjamin.gaignard@collabora.com> | 2023-11-09 19:29:14 +0300 |
---|---|---|
committer | Mauro Carvalho Chehab <mchehab@kernel.org> | 2023-11-23 13:47:08 +0300 |
commit | 3431e32cb585f3159ffd4ccceffa0d570bdd5744 (patch) | |
tree | a38a88156b4b3f04361899b623558eae402eedf0 /drivers/media/common/videobuf2/videobuf2-core.c | |
parent | 07cb30216d31bee8e4250549ebb4086ba5951887 (diff) | |
download | linux-3431e32cb585f3159ffd4ccceffa0d570bdd5744.tar.xz |
media: videobuf2: Rework offset 'cookie' encoding pattern
Change how offset 'cookie' field value is computed to make possible
to use more buffers.
The maximum number of buffers depends of PAGE_SHIFT value and can
go up to 0x7fff when PAGE_SHIFT = 12.
With this encoding pattern we know the maximum number that a queue
could store so we can check it at queue init time.
It also make easier and faster to find buffer and plane from using
the offset field.
Change __find_plane_by_offset() prototype to return the video buffer
itself rather than it index.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Diffstat (limited to 'drivers/media/common/videobuf2/videobuf2-core.c')
-rw-r--r-- | drivers/media/common/videobuf2/videobuf2-core.c | 78 |
1 files changed, 40 insertions, 38 deletions
diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c index e5fd7ff0dae6..0b7c6b297d12 100644 --- a/drivers/media/common/videobuf2/videobuf2-core.c +++ b/drivers/media/common/videobuf2/videobuf2-core.c @@ -31,6 +31,16 @@ #include <trace/events/vb2.h> +#define PLANE_INDEX_BITS 3 +#define PLANE_INDEX_SHIFT (PAGE_SHIFT + PLANE_INDEX_BITS) +#define PLANE_INDEX_MASK (BIT_MASK(PLANE_INDEX_BITS) - 1) +#define MAX_BUFFER_INDEX BIT_MASK(30 - PLANE_INDEX_SHIFT) +#define BUFFER_INDEX_MASK (MAX_BUFFER_INDEX - 1) + +#if BIT(PLANE_INDEX_BITS) != VIDEO_MAX_PLANES +#error PLANE_INDEX_BITS order must be equal to VIDEO_MAX_PLANES +#endif + static int debug; module_param(debug, int, 0644); @@ -358,21 +368,27 @@ static void __setup_offsets(struct vb2_buffer *vb) unsigned int plane; unsigned long offset = 0; - if (vb->index) { - struct vb2_buffer *prev = q->bufs[vb->index - 1]; - struct vb2_plane *p = &prev->planes[prev->num_planes - 1]; - - offset = PAGE_ALIGN(p->m.offset + p->length); - } + /* + * The offset "cookie" value has the following constraints: + * - a buffer can have up to 8 planes. + * - v4l2 mem2mem uses bit 30 to distinguish between + * OUTPUT (aka "source", bit 30 is 0) and + * CAPTURE (aka "destination", bit 30 is 1) buffers. + * - must be page aligned + * That led to this bit mapping when PAGE_SHIFT = 12: + * |30 |29 15|14 12|11 0| + * |DST_QUEUE_OFF_BASE|buffer index|plane index| 0 | + * where there are 15 bits to store the buffer index. + * Depending on PAGE_SHIFT value we can have fewer bits + * to store the buffer index. + */ + offset = vb->index << PLANE_INDEX_SHIFT; for (plane = 0; plane < vb->num_planes; ++plane) { - vb->planes[plane].m.offset = offset; + vb->planes[plane].m.offset = offset + (plane << PAGE_SHIFT); dprintk(q, 3, "buffer %d, plane %d offset 0x%08lx\n", vb->index, plane, offset); - - offset += vb->planes[plane].length; - offset = PAGE_ALIGN(offset); } } @@ -2188,10 +2204,9 @@ EXPORT_SYMBOL_GPL(vb2_core_streamoff); * __find_plane_by_offset() - find plane associated with the given offset */ static int __find_plane_by_offset(struct vb2_queue *q, unsigned long offset, - unsigned int *_buffer, unsigned int *_plane) + struct vb2_buffer **vb, unsigned int *plane) { - struct vb2_buffer *vb; - unsigned int buffer, plane; + unsigned int buffer; /* * Sanity checks to ensure the lock is held, MEMORY_MMAP is @@ -2209,24 +2224,15 @@ static int __find_plane_by_offset(struct vb2_queue *q, unsigned long offset, return -EBUSY; } - /* - * Go over all buffers and their planes, comparing the given offset - * with an offset assigned to each plane. If a match is found, - * return its buffer and plane numbers. - */ - for (buffer = 0; buffer < q->num_buffers; ++buffer) { - vb = q->bufs[buffer]; + /* Get buffer and plane from the offset */ + buffer = (offset >> PLANE_INDEX_SHIFT) & BUFFER_INDEX_MASK; + *plane = (offset >> PAGE_SHIFT) & PLANE_INDEX_MASK; - for (plane = 0; plane < vb->num_planes; ++plane) { - if (vb->planes[plane].m.offset == offset) { - *_buffer = buffer; - *_plane = plane; - return 0; - } - } - } + if (buffer >= q->num_buffers || *plane >= q->bufs[buffer]->num_planes) + return -EINVAL; - return -EINVAL; + *vb = q->bufs[buffer]; + return 0; } int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type, @@ -2306,7 +2312,7 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma) { unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; struct vb2_buffer *vb; - unsigned int buffer = 0, plane = 0; + unsigned int plane = 0; int ret; unsigned long length; @@ -2335,12 +2341,10 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma) * Find the plane corresponding to the offset passed by userspace. This * will return an error if not MEMORY_MMAP or file I/O is in progress. */ - ret = __find_plane_by_offset(q, offset, &buffer, &plane); + ret = __find_plane_by_offset(q, offset, &vb, &plane); if (ret) goto unlock; - vb = q->bufs[buffer]; - /* * MMAP requires page_aligned buffers. * The buffer length was page_aligned at __vb2_buf_mem_alloc(), @@ -2368,7 +2372,7 @@ unlock: if (ret) return ret; - dprintk(q, 3, "buffer %d, plane %d successfully mapped\n", buffer, plane); + dprintk(q, 3, "buffer %u, plane %d successfully mapped\n", vb->index, plane); return 0; } EXPORT_SYMBOL_GPL(vb2_mmap); @@ -2382,7 +2386,7 @@ unsigned long vb2_get_unmapped_area(struct vb2_queue *q, { unsigned long offset = pgoff << PAGE_SHIFT; struct vb2_buffer *vb; - unsigned int buffer, plane; + unsigned int plane; void *vaddr; int ret; @@ -2392,12 +2396,10 @@ unsigned long vb2_get_unmapped_area(struct vb2_queue *q, * Find the plane corresponding to the offset passed by userspace. This * will return an error if not MEMORY_MMAP or file I/O is in progress. */ - ret = __find_plane_by_offset(q, offset, &buffer, &plane); + ret = __find_plane_by_offset(q, offset, &vb, &plane); if (ret) goto unlock; - vb = q->bufs[buffer]; - vaddr = vb2_plane_vaddr(vb, plane); mutex_unlock(&q->mmap_lock); return vaddr ? (unsigned long)vaddr : -EINVAL; |