Until now the only way to make the driver allocate buffers and
share them using dma_buf was to use V4L2_MEMORY_MMAP memory type.
Use of MMAP memory type is a problem because vb2 never call
dma_buf_map_attachment() to attach itself while queuing the buffer
so dma_buf importer will not know that another device use this buffer.
This patch allow to allocate buffer even for DMABUF memory type
and correctly manage dma_buf buffer attachment.
vb2_mem_ops attach_dmabuf() prototype has been changed to be able
to distinguish if the attachment is done on a already existing
buffer or on imported one.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>
---
drivers/media/v4l2-core/videobuf2-core.c | 76 ++++++++++++++++++++++++--
drivers/media/v4l2-core/videobuf2-dma-contig.c | 10 ++--
drivers/media/v4l2-core/videobuf2-dma-sg.c | 8 ++-
drivers/media/v4l2-core/videobuf2-vmalloc.c | 8 ++-
include/media/videobuf2-core.h | 5 +-
5 files changed, 91 insertions(+), 16 deletions(-)
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 1329dcc..c5968aa 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -337,6 +337,67 @@ static void __setup_offsets(struct vb2_queue *q, unsigned int n)
}
/**
+ * __setup_dmabufs() - setup dmabuf fd for every plane in
+ * every buffer on the queue
+ */
+static void __setup_dmabufs(struct vb2_queue *q, unsigned int n)
+{
+ unsigned int buffer, plane;
+ struct vb2_buffer *vb;
+ struct vb2_plane *vb_plane;
+ struct dma_buf *dbuf;
+ void *mem_priv;
+ int fd;
+ int write = !V4L2_TYPE_IS_OUTPUT(q->type);
+ int flags = write ? O_WRONLY : O_RDONLY;
+
+ for (buffer = q->num_buffers; buffer < q->num_buffers + n; ++buffer) {
+ vb = q->bufs[buffer];
+ if (!vb)
+ continue;
+
+ for (plane = 0; plane < vb->num_planes; ++plane) {
+ vb_plane = &vb->planes[plane];
+
+ dbuf = call_ptr_memop(vb, get_dmabuf,
+ vb_plane->mem_priv,
+ flags & O_ACCMODE);
+ if (IS_ERR_OR_NULL(dbuf)) {
+ dprintk(1, "Failed to export buffer %d, " \
+ "plane %d\n", buffer, plane);
+ continue;
+ }
+
+ fd = dma_buf_fd(dbuf, flags & ~O_ACCMODE);
+ if (fd < 0) {
+ dprintk(3, "buffer %d, plane %d failed " \
+ "to export (%d)\n", buffer, plane, fd);
+ dma_buf_put(dbuf);
+ continue;
+ }
+
+ /* Acquire each plane's memory */
+ mem_priv = call_ptr_memop(vb, attach_dmabuf,
+ q->alloc_ctx[plane], dbuf,
+ vb->v4l2_planes[plane].length,
+ write, vb_plane->mem_priv);
+ if (IS_ERR(mem_priv)) {
+ dprintk(1, "Buffer %d plane %d failed "\
+ "to attach dmabuf\n", buffer, plane);
+ dma_buf_put(dbuf);
+ continue;
+ }
+
+ vb_plane->dbuf = dbuf;
+ vb->v4l2_planes[plane].m.fd = fd;
+
+ dprintk(3, "Buffer %d, plane %d fd %x\n",
+ buffer, plane, fd);
+ }
+ }
+}
+
+/**
* __vb2_queue_alloc() - allocate videobuf buffer structures and (for MMAP type)
* video buffer memory for all buffers/planes on the queue and initializes the
* queue
@@ -369,8 +430,9 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum v4l2_memory memory,
vb->v4l2_buf.type = q->type;
vb->v4l2_buf.memory = memory;
- /* Allocate video buffer memory for the MMAP type */
- if (memory == V4L2_MEMORY_MMAP) {
+ /* Allocate video buffer memory for the MMAP and DMABUF types */
+ if (memory == V4L2_MEMORY_MMAP ||
+ memory == V4L2_MEMORY_DMABUF) {
ret = __vb2_buf_mem_alloc(vb);
if (ret) {
dprintk(1, "failed allocating memory for "
@@ -400,6 +462,9 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum v4l2_memory memory,
if (memory == V4L2_MEMORY_MMAP)
__setup_offsets(q, buffer);
+ if (memory == V4L2_MEMORY_DMABUF)
+ __setup_dmabufs(q, buffer);
+
dprintk(1, "allocated %d buffers, %d plane(s) each\n",
buffer, num_planes);
@@ -859,7 +924,7 @@ static int __verify_memory_type(struct vb2_queue *q,
* 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
+ * 5) for MMAP and DMABUF memory types, 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.
@@ -885,7 +950,8 @@ static int __reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
* are not in use and can be freed.
*/
mutex_lock(&q->mmap_lock);
- if (q->memory == V4L2_MEMORY_MMAP && __buffers_in_use(q)) {
+ if ((q->memory == V4L2_MEMORY_MMAP ||
+ q->memory == V4L2_MEMORY_DMABUF) && __buffers_in_use(q)) {
mutex_unlock(&q->mmap_lock);
dprintk(1, "memory in use, cannot free\n");
return -EBUSY;
@@ -1540,7 +1606,7 @@ static int __qbuf_dmabuf(struct vb2_buffer *vb, const struct v4l2_buffer *b)
/* Acquire each plane's memory */
mem_priv = call_ptr_memop(vb, attach_dmabuf, q->alloc_ctx[plane],
- dbuf, planes[plane].length, dma_dir);
+ dbuf, planes[plane].length, dma_dir, NULL);
if (IS_ERR(mem_priv)) {
dprintk(1, "failed to attach dmabuf\n");
ret = PTR_ERR(mem_priv);
diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index b481d20..8dc945e 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -793,7 +793,7 @@ static void vb2_dc_detach_dmabuf(void *mem_priv)
struct vb2_dc_buf *buf = mem_priv;
/* if vb2 works correctly you should never detach mapped buffer */
- if (WARN_ON(buf->dma_addr))
+ if (WARN_ON(buf->dma_sgt))
vb2_dc_unmap_dmabuf(buf);
/* detach this attachment */
@@ -802,16 +802,18 @@ static void vb2_dc_detach_dmabuf(void *mem_priv)
}
static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
- unsigned long size, enum dma_data_direction dma_dir)
+ unsigned long size, enum dma_data_direction dma_dir, void *buf_priv)
{
struct vb2_dc_conf *conf = alloc_ctx;
- struct vb2_dc_buf *buf;
+ struct vb2_dc_buf *buf = buf_priv;
struct dma_buf_attachment *dba;
if (dbuf->size < size)
return ERR_PTR(-EFAULT);
- buf = kzalloc(sizeof(*buf), GFP_KERNEL);
+ if (!buf)
+ buf = kzalloc(sizeof(*buf), GFP_KERNEL);
+
if (!buf)
return ERR_PTR(-ENOMEM);
diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c
index b1838ab..b9855fd 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-sg.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c
@@ -667,16 +667,18 @@ static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
}
static void *vb2_dma_sg_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
- unsigned long size, enum dma_data_direction dma_dir)
+ unsigned long size, enum dma_data_direction dma_dir, void *buf_priv)
{
struct vb2_dma_sg_conf *conf = alloc_ctx;
- struct vb2_dma_sg_buf *buf;
+ struct vb2_dma_sg_buf *buf = buf_priv;
struct dma_buf_attachment *dba;
if (dbuf->size < size)
return ERR_PTR(-EFAULT);
- buf = kzalloc(sizeof(*buf), GFP_KERNEL);
+ if (!buf)
+ buf = kzalloc(sizeof(*buf), GFP_KERNEL);
+
if (!buf)
return ERR_PTR(-ENOMEM);
diff --git a/drivers/media/v4l2-core/videobuf2-vmalloc.c b/drivers/media/v4l2-core/videobuf2-vmalloc.c
index bcde885..373294c 100644
--- a/drivers/media/v4l2-core/videobuf2-vmalloc.c
+++ b/drivers/media/v4l2-core/videobuf2-vmalloc.c
@@ -416,14 +416,16 @@ static void vb2_vmalloc_detach_dmabuf(void *mem_priv)
}
static void *vb2_vmalloc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
- unsigned long size, enum dma_data_direction dma_dir)
+ unsigned long size, enum dma_data_direction dma_dir, void *buf_priv)
{
- struct vb2_vmalloc_buf *buf;
+ struct vb2_vmalloc_buf *buf = buf_priv;
if (dbuf->size < size)
return ERR_PTR(-EFAULT);
- buf = kzalloc(sizeof(*buf), GFP_KERNEL);
+ if (!buf)
+ buf = kzalloc(sizeof(*buf), GFP_KERNEL);
+
if (!buf)
return ERR_PTR(-ENOMEM);
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index a5790fd..374b26b 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -49,6 +49,8 @@ struct vb2_threadio_data;
* used for DMABUF memory types; alloc_ctx is the alloc context
* dbuf is the shared dma_buf; returns NULL on failure;
* allocator private per-buffer structure on success;
+ * if private per-buffer structure is provided reuse it
+ * instead of allocating a new one.
* this needs to be used for further accesses to the buffer.
* @detach_dmabuf: inform the exporter of the buffer that the current DMABUF
* buffer is no longer used; the buf_priv argument is the
@@ -98,7 +100,8 @@ struct vb2_mem_ops {
void *(*attach_dmabuf)(void *alloc_ctx, struct dma_buf *dbuf,
unsigned long size,
- enum dma_data_direction dma_dir);
+ enum dma_data_direction dma_dir,
+ void *buf_priv);
void (*detach_dmabuf)(void *buf_priv);
int (*map_dmabuf)(void *buf_priv);
void (*unmap_dmabuf)(void *buf_priv);
--
1.9.1
--
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