@@ -31,6 +31,10 @@
#include <trace/events/vb2.h>
+#define PLANE_INDEX_SHIFT 3
+#define PLANE_INDEX_MASK 0x7
+#define MAX_BUFFERS 0xffff
+
static int debug;
module_param(debug, int, 0644);
@@ -358,29 +362,23 @@ static void __setup_offsets(struct vb2_buffer *vb)
unsigned int plane;
unsigned long off = 0;
- if (vb->index) {
- struct vb2_buffer *prev;
- struct vb2_plane *p;
-
- prev = vb2_get_buffer(q, vb->index - 1);
- if (!prev) {
- dprintk(q, 1, "can't find the requested buffer\n");
- return;
- }
-
- p = &prev->planes[prev->num_planes - 1];
-
- off = PAGE_ALIGN(p->m.offset + p->length);
- }
+ /*
+ * Offsets cookies value have the following constraints:
+ * - a buffer could have up to 8 planes.
+ * - v4l2 mem2mem use bit 30 to distinguish between source and destination buffers.
+ * - must be page aligned
+ * That led to this bit mapping:
+ * |30 |29 15|14 12|11 0|
+ * |DST_QUEUE_OFF_BASE|buffer index|plane index| 0 |
+ * where there is 16 bits to store buffer index.
+ */
+ off = vb->index << (PLANE_INDEX_SHIFT + PAGE_SHIFT);
for (plane = 0; plane < vb->num_planes; ++plane) {
- vb->planes[plane].m.offset = off;
+ vb->planes[plane].m.offset = off + (plane << PAGE_SHIFT);
dprintk(q, 3, "buffer %d, plane %d offset 0x%08lx\n",
vb->index, plane, off);
-
- off += vb->planes[plane].length;
- off = PAGE_ALIGN(off);
}
}
@@ -2294,24 +2292,18 @@ static int __find_plane_by_offset(struct vb2_queue *q, unsigned long off,
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 = vb2_get_buffer(q, buffer);
+ /* Get buffer and plane from the offset */
+ buffer = (off >> (PLANE_INDEX_SHIFT + PAGE_SHIFT)) & MAX_BUFFERS;
+ plane = (off >> PAGE_SHIFT) & PLANE_INDEX_MASK;
- if (!vb)
- continue;
+ vb = vb2_get_buffer(q, buffer);
+ if (!vb)
+ return -EINVAL;
- for (plane = 0; plane < vb->num_planes; ++plane) {
- if (vb->planes[plane].m.offset == off) {
- *_buffer = buffer;
- *_plane = plane;
- return 0;
- }
- }
+ if (vb->planes[plane].m.offset == off) {
+ *_buffer = buffer;
+ *_plane = plane;
+ return 0;
}
return -EINVAL;
@@ -2552,6 +2544,9 @@ int vb2_core_queue_init(struct vb2_queue *q)
if (!q->max_allowed_buffers)
q->max_allowed_buffers = VB2_MAX_FRAME;
+ /* The maximum is limited by offset cookie encoding pattern */
+ q->max_allowed_buffers = min_t(unsigned int, q->max_allowed_buffers, MAX_BUFFERS);
+
q->bufs = kcalloc(q->max_allowed_buffers, sizeof(*q->bufs), GFP_KERNEL);
if (q->buf_struct_size == 0)
Change how offset 'cookie' field value is computed to make possible to use more buffers. With this encoding pattern we know the maximum number that a queue could store so we can check ing at queue init time. It also make easier and faster to find buffer and plane from using the offset field. Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com> --- .../media/common/videobuf2/videobuf2-core.c | 63 +++++++++---------- 1 file changed, 29 insertions(+), 34 deletions(-)