media: videobuf2: handle V4L2_MEMORY_FLAG_NON_COHERENT flag

This patch lets user-space 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 byte of a 4 byte ->reserved[1] member of struct
 v4l2_requestbuffers. The struct, thus, now has reserved 3 bytes.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
index f98f18c..a048a9f 100644 (file)
--- 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 e59306a..099fa66 100644 (file)
--- a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
@@ -104,10 +104,13 @@ 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.
-    * - __u32
-      - ``reserved``\ [1]
-      - A place holder for future extensions. Drivers and applications
-       must set the array to zero.
+    * - __u8
+      - ``flags``
+      - Specifies additional buffer management attributes.
+       See :ref:`memory-flags`.
+    * - __u8
+      - ``reserved``\ [3]
+      - Reserved for future extensions.
 
 .. _v4l2-buf-capabilities:
 .. _V4L2-BUF-CAP-SUPPORTS-MMAP:

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 60fb43b..2266bbd 100644 (file)
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -761,7 +761,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
 {
        unsigned int num_buffers, allocated_buffers, num_planes = 0;
        unsigned plane_sizes[VB2_MAX_PLANES] = { };
-       bool non_coherent_mem = false;
+       bool non_coherent_mem = flags & V4L2_MEMORY_FLAG_NON_COHERENT;
        unsigned int i;
        int ret;
 
@@ -905,7 +905,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
 {
        unsigned int num_planes = 0, num_buffers, allocated_buffers;
        unsigned plane_sizes[VB2_MAX_PLANES] = { };
-       bool non_coherent_mem = false;
+       bool non_coherent_mem = flags & V4L2_MEMORY_FLAG_NON_COHERENT;
        int ret;
 
        if (q->num_buffers == VB2_MAX_FRAME) {

diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index b4f70dd..6edf450 100644 (file)
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -692,12 +692,32 @@ static void fill_buf_caps(struct vb2_queue *q, u32 *caps)
 #endif
 }
 
+static void validate_memory_flags(struct vb2_queue *q,
+                                 int memory,
+                                 u32 *flags)
+{
+       if (!q->allow_cache_hints || memory != V4L2_MEMORY_MMAP) {
+               /*
+                * This needs to clear V4L2_MEMORY_FLAG_NON_COHERENT only,
+                * but in order to avoid bugs we zero out all bits.
+                */
+               *flags = 0;
+       } else {
+               /* Clear all unknown flags. */
+               *flags &= V4L2_MEMORY_FLAG_NON_COHERENT;
+       }
+}
+
 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
 {
        int ret = vb2_verify_memory_type(q, req->memory, req->type);
+       u32 flags = req->flags;
 
        fill_buf_caps(q, &req->capabilities);
-       return ret ? ret : vb2_core_reqbufs(q, req->memory, 0, &req->count);
+       validate_memory_flags(q, req->memory, &flags);
+       req->flags = flags;
+       return ret ? ret : vb2_core_reqbufs(q, req->memory,
+                                           req->flags, &req->count);
 }
 EXPORT_SYMBOL_GPL(vb2_reqbufs);
 
@@ -729,6 +749,7 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
        unsigned i;
 
        fill_buf_caps(q, &create->capabilities);
+       validate_memory_flags(q, create->memory, &create->flags);
        create->index = q->num_buffers;
        if (create->count == 0)
                return ret != -EBUSY ? ret : 0;
@@ -772,7 +793,7 @@ 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);
@@ -969,13 +990,16 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
 {
        struct video_device *vdev = video_devdata(file);
        int res = vb2_verify_memory_type(vdev->queue, p->memory, p->type);
+       u32 flags = p->flags;
 
        fill_buf_caps(vdev->queue, &p->capabilities);
+       validate_memory_flags(vdev->queue, p->memory, &flags);
+       p->flags = 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)
@@ -993,6 +1017,7 @@ int vb2_ioctl_create_bufs(struct file *file, void *priv,
 
        p->index = vdev->queue->num_buffers;
        fill_buf_caps(vdev->queue, &p->capabilities);
+       validate_memory_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 47aff3b..8176769 100644 (file)
--- 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 bc83d23..31d0109 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -2024,7 +2024,7 @@ static int v4l_reqbufs(const struct v4l2_ioctl_ops *ops,
        if (ret)
                return ret;
 
-       CLEAR_AFTER_FIELD(p, capabilities);
+       CLEAR_AFTER_FIELD(p, flags);
 
        return ops->vidioc_reqbufs(file, fh, p);
 }
@@ -2065,7 +2065,7 @@ 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 9b7032a..f118fe7 100644 (file)
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -959,7 +959,8 @@ struct v4l2_requestbuffers {
        __u32                   type;           /* enum v4l2_buf_type */
        __u32                   memory;         /* enum v4l2_memory */
        __u32                   capabilities;
-       __u32                   reserved[1];
+       __u8                    flags;
+       __u8                    reserved[3];
 };
 
 #define V4L2_MEMORY_FLAG_NON_COHERENT                  (1 << 0)
@@ -2507,6 +2508,9 @@ 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 {
@@ -2515,7 +2519,8 @@ struct v4l2_create_buffers {
        __u32                   memory;
        struct v4l2_format      format;
        __u32                   capabilities;
-       __u32                   reserved[7];
+       __u32                   flags;
+       __u32                   reserved[6];
 };
 
 /*