[PATCHv3 6/8] videobuf2: add queue memory coherency parameter

Sergey Senozhatsky
2021-07-09T09:20:56Z

Preparations for future V4L2_MEMORY_FLAG_NON_COHERENT support.

Extend vb2_core_reqbufs() parameters list to accept requests'
->flags, which will be used for memory coherency configuration.

An attempt to allocate a buffer with coherency requirements
which don't match queue's consistency model will fail.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
.../media/common/videobuf2/videobuf2-core.c | 38 ++++++++++++++++---
.../media/common/videobuf2/videobuf2-v4l2.c | 5 ++-
drivers/media/dvb-core/dvb_vb2.c | 2 +-
include/media/videobuf2-core.h | 10 ++++-
4 files changed, 44 insertions(+), 11 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 55af63d54f23..af4db310cf5e 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -738,11 +738,31 @@ int vb2_verify_memory_type(struct vb2_queue *q,
}
EXPORT_SYMBOL(vb2_verify_memory_type);

+static void set_queue_coherency(struct vb2_queue *q, bool coherent_mem)
+{
+ q->coherent_mem = 1;
+
+ if (!vb2_queue_allows_cache_hints(q))
+ return;
+ if (!coherent_mem)
+ q->coherent_mem = 0;
+}
+
+static bool verify_coherency_flags(struct vb2_queue *q, bool coherent_mem)
+{
+ if (coherent_mem != q->coherent_mem) {
+ dprintk(q, 1, "memory coherency model mismatch\n");
+ return false;
+ }
+ return true;
+}
+
int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
- unsigned int *count)
+ unsigned int flags, unsigned int *count)
{
unsigned int num_buffers, allocated_buffers, num_planes = 0;
unsigned plane_sizes[VB2_MAX_PLANES] = { };
+ bool coherent_mem = true;
unsigned int i;
int ret;

@@ -757,7 +777,8 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
}

if (*count == 0 || q->num_buffers != 0 ||
- (q->memory != VB2_MEMORY_UNKNOWN && q->memory != memory)) {
+ (q->memory != VB2_MEMORY_UNKNOWN && q->memory != memory) ||
+ !verify_coherency_flags(q, coherent_mem)) {
/*
* We already have buffers allocated, so first check if they
* are not in use and can be freed.
@@ -794,6 +815,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
num_buffers = min_t(unsigned int, num_buffers, VB2_MAX_FRAME);
memset(q->alloc_devs, 0, sizeof(q->alloc_devs));
q->memory = memory;
+ set_queue_coherency(q, coherent_mem);

/*
* Ask the driver how many buffers and planes per buffer it requires.
@@ -878,12 +900,13 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
EXPORT_SYMBOL_GPL(vb2_core_reqbufs);

int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
- unsigned int *count,
+ unsigned int flags, unsigned int *count,
unsigned int requested_planes,
const unsigned int requested_sizes[])
{
unsigned int num_planes = 0, num_buffers, allocated_buffers;
unsigned plane_sizes[VB2_MAX_PLANES] = { };
+ bool coherent_mem = true;
int ret;

if (q->num_buffers == VB2_MAX_FRAME) {
@@ -899,11 +922,14 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
memset(q->alloc_devs, 0, sizeof(q->alloc_devs));
q->memory = memory;
q->waiting_for_buffers = !q->is_output;
+ set_queue_coherency(q, coherent_mem);
} else {
if (q->memory != memory) {
dprintk(q, 1, "memory model mismatch\n");
return -EINVAL;
}
+ if (!verify_coherency_flags(q, coherent_mem))
+ return -EINVAL;
}

num_buffers = min(*count, VB2_MAX_FRAME - q->num_buffers);
@@ -2576,7 +2602,7 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read)
fileio->memory = VB2_MEMORY_MMAP;
fileio->type = q->type;
q->fileio = fileio;
- ret = vb2_core_reqbufs(q, fileio->memory, &fileio->count);
+ ret = vb2_core_reqbufs(q, fileio->memory, 0, &fileio->count);
if (ret)
goto err_kfree;

@@ -2633,7 +2659,7 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read)

err_reqbufs:
fileio->count = 0;
- vb2_core_reqbufs(q, fileio->memory, &fileio->count);
+ vb2_core_reqbufs(q, fileio->memory, 0, &fileio->count);

err_kfree:
q->fileio = NULL;
@@ -2653,7 +2679,7 @@ static int __vb2_cleanup_fileio(struct vb2_queue *q)
vb2_core_streamoff(q, q->type);
q->fileio = NULL;
fileio->count = 0;
- vb2_core_reqbufs(q, fileio->memory, &fileio->count);
+ vb2_core_reqbufs(q, fileio->memory, 0, &fileio->count);
kfree(fileio);
dprintk(q, 3, "file io emulator closed\n");
}
diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index 2fbae9bd7b52..b4f70ddb09b0 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -697,7 +697,7 @@ int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
int ret = vb2_verify_memory_type(q, req->memory, req->type);

fill_buf_caps(q, &req->capabilities);
- return ret ? ret : vb2_core_reqbufs(q, req->memory, &req->count);
+ return ret ? ret : vb2_core_reqbufs(q, req->memory, 0, &req->count);
}
EXPORT_SYMBOL_GPL(vb2_reqbufs);

@@ -772,6 +772,7 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
if (requested_sizes[i] == 0)
return -EINVAL;
return ret ? ret : vb2_core_create_bufs(q, create->memory,
+ 0,
&create->count,
requested_planes,
requested_sizes);
@@ -974,7 +975,7 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
return res;
if (vb2_queue_is_busy(vdev, file))
return -EBUSY;
- res = vb2_core_reqbufs(vdev->queue, p->memory, &p->count);
+ res = vb2_core_reqbufs(vdev->queue, p->memory, 0, &p->count);
/* If count == 0, then the owner has released all buffers and he
is no longer owner of the queue. Otherwise we have a new owner. */
if (res == 0)
diff --git a/drivers/media/dvb-core/dvb_vb2.c b/drivers/media/dvb-core/dvb_vb2.c
index 6974f1731529..959d110407a4 100644
--- a/drivers/media/dvb-core/dvb_vb2.c
+++ b/drivers/media/dvb-core/dvb_vb2.c
@@ -342,7 +342,7 @@ int dvb_vb2_reqbufs(struct dvb_vb2_ctx *ctx, struct dmx_requestbuffers *req)

ctx->buf_siz = req->size;
ctx->buf_cnt = req->count;
- ret = vb2_core_reqbufs(&ctx->vb_q, VB2_MEMORY_MMAP, &req->count);
+ ret = vb2_core_reqbufs(&ctx->vb_q, VB2_MEMORY_MMAP, 0, &req->count);
if (ret) {
ctx->state = DVB_VB2_STATE_NONE;
dprintk(1, "[%s] count=%d size=%d errno=%d\n", ctx->name,
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 66e548268242..7e748cd09b7a 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -504,6 +504,8 @@ struct vb2_buf_ops {
* @allow_cache_hints: when set user-space can pass cache management hints in
* order to skip cache flush/invalidation on ->prepare() or/and
* ->finish().
+ * @coherent_mem: when cleared queue will attempt to allocate buffers using
+ * non-coherent memory.
* @lock: pointer to a mutex that protects the &struct vb2_queue. The
* driver can set this to a mutex to let the v4l2 core serialize
* the queuing ioctls. If the driver wants to handle locking
@@ -583,6 +585,7 @@ struct vb2_queue {
unsigned int uses_qbuf:1;
unsigned int uses_requests:1;
unsigned int allow_cache_hints:1;
+ unsigned int coherent_mem:1;

struct mutex *lock;
void *owner;
@@ -748,6 +751,8 @@ void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb);
* vb2_core_reqbufs() - Initiate streaming.
* @q: pointer to &struct vb2_queue with videobuf2 queue.
* @memory: memory type, as defined by &enum vb2_memory.
+ * @flags: auxiliary queue/buffer management flags. Currently, the only
+ * used flag is %V4L2_MEMORY_FLAG_NON_COHERENT.
* @count: requested buffer count.
*
* Videobuf2 core helper to implement VIDIOC_REQBUF() operation. It is called
@@ -772,12 +777,13 @@ void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb);
* Return: returns zero on success; an error code otherwise.
*/
int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
- unsigned int *count);
+ unsigned int flags, unsigned int *count);

/**
* vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs
* @q: pointer to &struct vb2_queue with videobuf2 queue.
* @memory: memory type, as defined by &enum vb2_memory.
+ * @flags: auxiliary queue/buffer management flags.
* @count: requested buffer count.
* @requested_planes: number of planes requested.
* @requested_sizes: array with the size of the planes.
@@ -795,7 +801,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
* Return: returns zero on success; an error code otherwise.
*/
int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
- unsigned int *count,
+ unsigned int flags, unsigned int *count,
unsigned int requested_planes,
const unsigned int requested_sizes[]);

--
2.32.0.93.g670b81a890-goog