[PATCH 7/8] videobuf2: handle V4L2_FLAG_MEMORY_NON_COHERENT flag
From: Sergey Senozhatsky
Date: Tue Mar 02 2021 - 02:48:06 EST
This patch lets user-space to request a non-coherent memory
allocation during CREATE_BUFS and REQBUFS ioctl calls.
= CREATE_BUFS
struct v4l2_create_buffers has seven 4-byte reserved areas,
so reserved[0] is renamed to ->flags. The struct, thus, now
has six reserved 4-byte regions.
= CREATE_BUFS32
struct v4l2_create_buffers32 has seven 4-byte reserved areas,
so reserved[0] is renamed to ->flags. The struct, thus, now
has six reserved 4-byte regions.
= REQBUFS
We use one bit of a ->reserved[1] member of struct v4l2_requestbuffers,
which is now renamed to ->flags. Unlike v4l2_create_buffers, struct
v4l2_requestbuffers does not have enough reserved room. Therefore for
backward compatibility ->reserved and ->flags were put into anonymous
union.
Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
---
.../media/v4l/vidioc-create-bufs.rst | 7 ++++++-
.../media/v4l/vidioc-reqbufs.rst | 11 +++++++++--
.../media/common/videobuf2/videobuf2-core.c | 6 ++++++
.../media/common/videobuf2/videobuf2-v4l2.c | 19 ++++++++++++++++---
drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 9 ++++++++-
drivers/media/v4l2-core/v4l2-ioctl.c | 5 +----
include/uapi/linux/videodev2.h | 11 +++++++++--
7 files changed, 55 insertions(+), 13 deletions(-)
diff --git a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
index b06e5b528e11..132c8b612a94 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
@@ -113,7 +113,12 @@ than the number requested.
``V4L2_MEMORY_MMAP`` and ``format.type`` to the buffer type.
* - __u32
- - ``reserved``\ [7]
+ - ``flags``
+ - Specifies additional buffer management attributes.
+ See :ref:`memory-flags`.
+
+ * - __u32
+ - ``reserved``\ [6]
- A place holder for future extensions. Drivers and applications
must set the array to zero.
diff --git a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
index 950e7ec1aac5..80ea48acea84 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
@@ -104,10 +104,17 @@ aborting or finishing any DMA in progress, an implicit
``V4L2_MEMORY_MMAP`` and ``type`` set to the buffer type. This will
free any previously allocated buffers, so this is typically something
that will be done at the start of the application.
+ * - union {
+ - (anonymous)
+ * - __u32
+ - ``flags``
+ - Specifies additional buffer management attributes.
+ See :ref:`memory-flags`.
* - __u32
- ``reserved``\ [1]
- - A place holder for future extensions. Drivers and applications
- must set the array to zero.
+ - Kept for backwards compatibility. Use ``flags`` instead.
+ * - }
+ -
.. tabularcolumns:: |p{6.1cm}|p{2.2cm}|p{8.7cm}|
diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 7040b7f47133..5906a48e7757 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -768,6 +768,9 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
unsigned int i;
int ret;
+ if (flags & V4L2_FLAG_MEMORY_NON_COHERENT)
+ coherent_mem = false;
+
if (q->streaming) {
dprintk(q, 1, "streaming active\n");
return -EBUSY;
@@ -911,6 +914,9 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
bool coherent_mem = true;
int ret;
+ if (flags & V4L2_FLAG_MEMORY_NON_COHERENT)
+ coherent_mem = false;
+
if (q->num_buffers == VB2_MAX_FRAME) {
dprintk(q, 1, "maximum number of buffers already allocated\n");
return -ENOBUFS;
diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index 1166d5a9291a..f6a8dcc1b5c6 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -692,12 +692,22 @@ static void fill_buf_caps(struct vb2_queue *q, u32 *caps)
#endif
}
+static void validate_coherency_flags(struct vb2_queue *q,
+ int memory,
+ unsigned int *flags)
+{
+ if (!q->allow_cache_hints || memory != V4L2_MEMORY_MMAP)
+ *flags &= ~V4L2_FLAG_MEMORY_NON_COHERENT;
+}
+
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, 0, &req->count);
+ validate_coherency_flags(q, req->memory, &req->flags);
+ return ret ? ret : vb2_core_reqbufs(q, req->memory,
+ req->flags, &req->count);
}
EXPORT_SYMBOL_GPL(vb2_reqbufs);
@@ -729,6 +739,7 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
unsigned i;
fill_buf_caps(q, &create->capabilities);
+ validate_coherency_flags(q, create->memory, &create->flags);
create->index = q->num_buffers;
if (create->count == 0)
return ret != -EBUSY ? ret : 0;
@@ -772,7 +783,7 @@ 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->flags,
&create->count,
requested_planes,
requested_sizes);
@@ -957,11 +968,12 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
int res = vb2_verify_memory_type(vdev->queue, p->memory, p->type);
fill_buf_caps(vdev->queue, &p->capabilities);
+ validate_coherency_flags(vdev->queue, p->memory, &p->flags);
if (res)
return res;
if (vb2_queue_is_busy(vdev, file))
return -EBUSY;
- res = vb2_core_reqbufs(vdev->queue, p->memory, 0, &p->count);
+ res = vb2_core_reqbufs(vdev->queue, p->memory, p->flags, &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)
@@ -979,6 +991,7 @@ int vb2_ioctl_create_bufs(struct file *file, void *priv,
p->index = vdev->queue->num_buffers;
fill_buf_caps(vdev->queue, &p->capabilities);
+ validate_coherency_flags(vdev->queue, p->memory, &p->flags);
/*
* If count == 0, then just check if memory and type are valid.
* Any -EBUSY result from vb2_verify_memory_type can be mapped to 0.
diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index 0ca75f6784c5..1aa9ca3b6ca4 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -126,6 +126,9 @@ struct v4l2_format32 {
* @memory: buffer memory type
* @format: frame format, for which buffers are requested
* @capabilities: capabilities of this buffer type.
+ * @flags: additional buffer management attributes (ignored unless the
+ * queue has V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS capability and
+ * configured for MMAP streaming I/O).
* @reserved: future extensions
*/
struct v4l2_create_buffers32 {
@@ -134,7 +137,8 @@ struct v4l2_create_buffers32 {
__u32 memory; /* enum v4l2_memory */
struct v4l2_format32 format;
__u32 capabilities;
- __u32 reserved[7];
+ __u32 flags;
+ __u32 reserved[6];
};
static int get_v4l2_format32(struct v4l2_format *p64,
@@ -182,6 +186,8 @@ static int get_v4l2_create32(struct v4l2_create_buffers *p64,
if (copy_from_user(p64, p32,
offsetof(struct v4l2_create_buffers32, format)))
return -EFAULT;
+ if (copy_from_user(&p64->flags, &p32->flags, sizeof(p32->flags)))
+ return -EFAULT;
return get_v4l2_format32(&p64->format, &p32->format);
}
@@ -227,6 +233,7 @@ static int put_v4l2_create32(struct v4l2_create_buffers *p64,
if (copy_to_user(p32, p64,
offsetof(struct v4l2_create_buffers32, format)) ||
put_user(p64->capabilities, &p32->capabilities) ||
+ put_user(p64->flags, &p32->flags) ||
copy_to_user(p32->reserved, p64->reserved, sizeof(p64->reserved)))
return -EFAULT;
return put_v4l2_format32(&p64->format, &p32->format);
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 31d1342e61e8..f8d38a3cd1e0 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -2045,9 +2045,6 @@ static int v4l_reqbufs(const struct v4l2_ioctl_ops *ops,
if (ret)
return ret;
-
- CLEAR_AFTER_FIELD(p, capabilities);
-
return ops->vidioc_reqbufs(file, fh, p);
}
@@ -2087,7 +2084,7 @@ static int v4l_create_bufs(const struct v4l2_ioctl_ops *ops,
if (ret)
return ret;
- CLEAR_AFTER_FIELD(create, capabilities);
+ CLEAR_AFTER_FIELD(create, flags);
v4l_sanitize_format(&create->format);
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index b1d4171fe50b..85d2681e73b6 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -951,7 +951,10 @@ struct v4l2_requestbuffers {
__u32 type; /* enum v4l2_buf_type */
__u32 memory; /* enum v4l2_memory */
__u32 capabilities;
- __u32 reserved[1];
+ union {
+ __u32 flags;
+ __u32 reserved[1];
+ };
};
#define V4L2_FLAG_MEMORY_NON_COHERENT (1 << 0)
@@ -2473,6 +2476,9 @@ struct v4l2_dbg_chip_info {
* @memory: enum v4l2_memory; buffer memory type
* @format: frame format, for which buffers are requested
* @capabilities: capabilities of this buffer type.
+ * @flags: additional buffer management attributes (ignored unless the
+ * queue has V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS capability
+ * and configured for MMAP streaming I/O).
* @reserved: future extensions
*/
struct v4l2_create_buffers {
@@ -2481,7 +2487,8 @@ struct v4l2_create_buffers {
__u32 memory;
struct v4l2_format format;
__u32 capabilities;
- __u32 reserved[7];
+ __u32 flags;
+ __u32 reserved[6];
};
/*
--
2.30.1.766.gb4fecdf3b7-goog