[PATCHv10 00/26] Integration of videobuf2 with DMABUF

[PATCHv10 00/26] Integration of videobuf2 with DMABUF

[Tomasz Stanislawski]

Hello everyone,
This patchset adds support for DMABUF [2] importing and exporting to V4L2
stack.

v10:
- rebase on media-next 3.7
- typos and style fixes in Documentation (from Hans Verkuil)
- fix compilation error with __fill_vb2_buffer
- fix uninitialized data_offset for single-planar queue
- support for DMABUF importing in S5P-FIMC mem-to-mem interface
- update layout of v4l2_exportbuffer structure
- update ioctl flags in v4l2_ioctls for VIDIOC_EXPBUF
- support for DMABUF exporting in m2m framework
- allow exporting for file handles that calle REQBUBS/CREATE_BUF
- simplify handling of get_device in vb2_dc_alloc
- reduce pr_err to pr_debug while checking alignment of userptr
- check size of userptr buffer against zero
- align size to PAGE_SIZE at allocation of dma-contig buffer

v9:
- rebase on 3.6
- change type for fs to __s32
- add support for vb2_ioctl_expbuf
- remove patch 'v4l: vb2: add support for DMA_ATTR_NO_KERNEL_MAPPING',
  it will be posted as a separate patch
- fix typos and style in Documentation (from Hans Verkuil)
- only vb2-core and vb2-dma-contig selects DMA_SHARED_BUFFER in Kconfig
- use data_offset and length while queueing DMABUF
- return the most recently used fd at VIDIOC_DQBUF
- use (buffer-type, index, plane) tuple instead of mem_offset
  to identify a for exporting (from Hans Verkuil)
- support for DMABUF mmap in vb2-dma-contig (from Laurent Pinchart)
- add testing alignment of vaddr and size while verifying userptr
  against DMA capabilities (from Laurent Pinchart)
- substitute VM_DONTDUMP with VM_RESERVED
- simplify error handling in vb2_dc_get_dmabuf (from Laurent Pinchart)

v8:
- rebased on 3.6-rc1
- merged importer and exporter patchsets
- fixed missing fields in v4l2_plane32 and v4l2_buffer32 structs
- fixed typos/style in documentation
- significant reduction of warnings from checkpatch.pl
- fixed STREAMOFF issues reported by Dima Zavin [4] by adding
  __vb2_dqbuf helper to vb2-core
- DC fails if userptr is not correctly aligned
- add support for DMA attributes in DC
- add support for buffers with no kernel mapping
- add reference counting on device from allocator context
- dummy support for mmap
- use dma_get_sgtable, drop vb2_dc_kaddr_to_pages hack and
  vb2_dc_get_base_sgt helper

v7:
- support for V4L2_MEMORY_DMABUF in v4l2-compact-ioctl32.c
- cosmetic fixes to the documentation
- added importing for vmalloc because vmap support in dmabuf for 3.5
  was pull-requested
- support for dmabuf importing for VIVI
- resurrect allocation of dma-contig context
- remove reference of alloc_ctx in dma-contig buffer
- use sg_alloc_table_from_pages
- fix DMA scatterlist calls to use orig_nents instead of nents
- fix memleak in vb2_dc_sgt_foreach_page (use orig_nents instead of nents)

v6:
- fixed missing entry in v4l2_memory_names
- fixed a bug occuring after get_user_pages failure
- fixed a bug caused by using invalid vma for get_user_pages
- prepare/finish no longer call dma_sync for dmabuf buffers

v5:
- removed change of importer/exporter behaviour
- fixes vb2_dc_pages_to_sgt basing on Laurent's hints
- changed pin/unpin words to lock/unlock in Doc

v4:
- rebased on mainline 3.4-rc2
- included missing importing support for s5p-fimc and s5p-tv
- added patch for changing map/unmap for importers
- fixes to Documentation part
- coding style fixes
- pairing {map/unmap}_dmabuf in vb2-core
- fixing variable types and semantic of arguments in videobufb2-dma-contig.c

v3:
- rebased on mainline 3.4-rc1
- split 'code refactor' patch to multiple smaller patches
- squashed fixes to Sumit's patches
- patchset is no longer dependant on 'DMA mapping redesign'
- separated path for handling IO and non-IO mappings
- add documentation for DMABUF importing to V4L
- removed all DMABUF exporter related code
- removed usage of dma_get_pages extension

v2:
- extended VIDIOC_EXPBUF argument from integer memoffset to struct
  v4l2_exportbuffer
- added patch that breaks DMABUF spec on (un)map_atachment callcacks but allows
  to work with existing implementation of DMABUF prime in DRM
- all dma-contig code refactoring patches were squashed
- bugfixes

v1: List of changes since [1].
- support for DMA api extension dma_get_pages, the function is used to retrieve
  pages used to create DMA mapping.
- small fixes/code cleanup to videobuf2
- added prepare and finish callbacks to vb2 allocators, it is used keep
  consistency between dma-cpu acess to the memory (by Marek Szyprowski)
- support for exporting of DMABUF buffer in V4L2 and Videobuf2, originated from
  [3].
- support for dma-buf exporting in vb2-dma-contig allocator
- support for DMABUF for s5p-tv and s5p-fimc (capture interface) drivers,
  originated from [3]
- changed handling for userptr buffers (by Marek Szyprowski, Andrzej
  Pietrasiewicz)
- let mmap method to use dma_mmap_writecombine call (by Marek Szyprowski)

[1] http://thread.gmane.org/gmane.linux.drivers.video-input-infrastructure/42966/focus=42968
[2] https://lkml.org/lkml/2011/12/26/29
[3] http://thread.gmane.org/gmane.linux.kernel.cross-arch/12819
[4] http://article.gmane.org/gmane.linux.drivers.video-input-infrastructure/49700

Laurent Pinchart (2):
  v4l: vb2-dma-contig: shorten vb2_dma_contig prefix to vb2_dc
  v4l: vb2-dma-contig: reorder functions

Marek Szyprowski (4):
  v4l: vb2: add prepare/finish callbacks to allocators
  v4l: vb2-dma-contig: add prepare/finish to dma-contig allocator
  v4l: vb2-dma-contig: let mmap method to use dma_mmap_coherent call
  v4l: vb2-dma-contig: fail if user ptr buffer is not correctly aligned

Sumit Semwal (4):
  v4l: Add DMABUF as a memory type
  v4l: vb2: add support for shared buffer (dma_buf)
  v4l: vb: remove warnings about MEMORY_DMABUF
  v4l: vb2-dma-contig: add support for dma_buf importing

Tomasz Stanislawski (16):
  Documentation: media: description of DMABUF importing in V4L2
  v4l: vb2-dma-contig: remove reference of alloc_ctx from a buffer
  v4l: vb2-dma-contig: add support for scatterlist in userptr mode
  v4l: vb2-vmalloc: add support for dmabuf importing
  v4l: vivi: support for dmabuf importing
  v4l: s5p-tv: mixer: support for dmabuf importing
  v4l: s5p-fimc: support for dmabuf importing
  Documentation: media: description of DMABUF exporting in V4L2
  v4l: add buffer exporting via dmabuf
  v4l: vb2: add buffer exporting via dmabuf
  v4l: vb2-dma-contig: add support for DMABUF exporting
  v4l: vb2-dma-contig: add reference counting for a device from
    allocator context
  v4l: vb2-dma-contig: align buffer size to PAGE_SIZE
  v4l: s5p-fimc: support for dmabuf exporting
  v4l: s5p-tv: mixer: support for dmabuf exporting
  v4l: s5p-mfc: support for dmabuf exporting

 Documentation/DocBook/media/v4l/compat.xml         |    7 +
 Documentation/DocBook/media/v4l/io.xml             |  184 ++++-
 Documentation/DocBook/media/v4l/v4l2.xml           |    1 +
 .../DocBook/media/v4l/vidioc-create-bufs.xml       |   16 +-
 Documentation/DocBook/media/v4l/vidioc-expbuf.xml  |  212 ++++++
 Documentation/DocBook/media/v4l/vidioc-qbuf.xml    |   17 +
 Documentation/DocBook/media/v4l/vidioc-reqbufs.xml |   47 +-
 drivers/media/platform/s5p-fimc/fimc-capture.c     |   11 +-
 drivers/media/platform/s5p-fimc/fimc-m2m.c         |   14 +-
 drivers/media/platform/s5p-mfc/s5p_mfc_dec.c       |   14 +
 drivers/media/platform/s5p-mfc/s5p_mfc_enc.c       |   14 +
 drivers/media/platform/s5p-tv/mixer_video.c        |   12 +-
 drivers/media/platform/vivi.c                      |    2 +-
 drivers/media/v4l2-core/Kconfig                    |    3 +
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c      |   19 +
 drivers/media/v4l2-core/v4l2-dev.c                 |    1 +
 drivers/media/v4l2-core/v4l2-ioctl.c               |   11 +
 drivers/media/v4l2-core/v4l2-mem2mem.c             |   13 +
 drivers/media/v4l2-core/videobuf-core.c            |    4 +
 drivers/media/v4l2-core/videobuf2-core.c           |  300 ++++++++-
 drivers/media/v4l2-core/videobuf2-dma-contig.c     |  702 ++++++++++++++++++--
 drivers/media/v4l2-core/videobuf2-memops.c         |   40 --
 drivers/media/v4l2-core/videobuf2-vmalloc.c        |   56 ++
 include/linux/videodev2.h                          |   35 +
 include/media/v4l2-ioctl.h                         |    2 +
 include/media/v4l2-mem2mem.h                       |    3 +
 include/media/videobuf2-core.h                     |   38 ++
 include/media/videobuf2-memops.h                   |    5 -
 28 files changed, 1645 insertions(+), 138 deletions(-)
 create mode 100644 Documentation/DocBook/media/v4l/vidioc-expbuf.xml

-- 
1.7.9.5

[PATCHv10 01/26] v4l: Add DMABUF as a memory type

[Tomasz Stanislawski]

From: Sumit Semwal <sumit.semwal@ti.com>

Adds DMABUF memory type to v4l framework. Also adds the related file
descriptor in v4l2_plane and v4l2_buffer.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
   [original work in the PoC for buffer sharing]
Signed-off-by: Sumit Semwal <sumit.semwal@ti.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c |   18 ++++++++++++++++++
 drivers/media/v4l2-core/v4l2-ioctl.c          |    1 +
 include/linux/videodev2.h                     |    7 +++++++
 3 files changed, 26 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index 83ffb64..cc5998b 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -297,6 +297,7 @@ struct v4l2_plane32 {
 	union {
 		__u32		mem_offset;
 		compat_long_t	userptr;
+		__s32		fd;
 	} m;
 	__u32			data_offset;
 	__u32			reserved[11];
@@ -318,6 +319,7 @@ struct v4l2_buffer32 {
 		__u32           offset;
 		compat_long_t   userptr;
 		compat_caddr_t  planes;
+		__s32		fd;
 	} m;
 	__u32			length;
 	__u32			reserved2;
@@ -341,6 +343,9 @@ static int get_v4l2_plane32(struct v4l2_plane *up, struct v4l2_plane32 *up32,
 		up_pln = compat_ptr(p);
 		if (put_user((unsigned long)up_pln, &up->m.userptr))
 			return -EFAULT;
+	} else if (memory == V4L2_MEMORY_DMABUF) {
+		if (copy_in_user(&up->m.fd, &up32->m.fd, sizeof(int)))
+			return -EFAULT;
 	} else {
 		if (copy_in_user(&up->m.mem_offset, &up32->m.mem_offset,
 					sizeof(__u32)))
@@ -364,6 +369,11 @@ static int put_v4l2_plane32(struct v4l2_plane *up, struct v4l2_plane32 *up32,
 		if (copy_in_user(&up32->m.mem_offset, &up->m.mem_offset,
 					sizeof(__u32)))
 			return -EFAULT;
+	/* For DMABUF, driver might've set up the fd, so copy it back. */
+	if (memory == V4L2_MEMORY_DMABUF)
+		if (copy_in_user(&up32->m.fd, &up->m.fd,
+					sizeof(int)))
+			return -EFAULT;
 
 	return 0;
 }
@@ -446,6 +456,10 @@ static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
 			if (get_user(kp->m.offset, &up->m.offset))
 				return -EFAULT;
 			break;
+		case V4L2_MEMORY_DMABUF:
+			if (get_user(kp->m.fd, &up->m.fd))
+				return -EFAULT;
+			break;
 		}
 	}
 
@@ -510,6 +524,10 @@ static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
 			if (put_user(kp->m.offset, &up->m.offset))
 				return -EFAULT;
 			break;
+		case V4L2_MEMORY_DMABUF:
+			if (put_user(kp->m.fd, &up->m.fd))
+				return -EFAULT;
+			break;
 		}
 	}
 
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 8f388ff..530a67e 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -155,6 +155,7 @@ static const char *v4l2_memory_names[] = {
 	[V4L2_MEMORY_MMAP]    = "mmap",
 	[V4L2_MEMORY_USERPTR] = "userptr",
 	[V4L2_MEMORY_OVERLAY] = "overlay",
+	[V4L2_MEMORY_DMABUF] = "dmabuf",
 };
 
 #define prt_names(a, arr) (((unsigned)(a)) < ARRAY_SIZE(arr) ? arr[a] : "unknown")
diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index 873adbe..07bc5d6 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -188,6 +188,7 @@ enum v4l2_memory {
 	V4L2_MEMORY_MMAP             = 1,
 	V4L2_MEMORY_USERPTR          = 2,
 	V4L2_MEMORY_OVERLAY          = 3,
+	V4L2_MEMORY_DMABUF           = 4,
 };
 
 /* see also http://vektor.theorem.ca/graphics/ycbcr/ */
@@ -604,6 +605,8 @@ struct v4l2_requestbuffers {
  *			should be passed to mmap() called on the video node)
  * @userptr:		when memory is V4L2_MEMORY_USERPTR, a userspace pointer
  *			pointing to this plane
+ * @fd:			when memory is V4L2_MEMORY_DMABUF, a userspace file
+ *			descriptor associated with this plane
  * @data_offset:	offset in the plane to the start of data; usually 0,
  *			unless there is a header in front of the data
  *
@@ -618,6 +621,7 @@ struct v4l2_plane {
 	union {
 		__u32		mem_offset;
 		unsigned long	userptr;
+		__s32		fd;
 	} m;
 	__u32			data_offset;
 	__u32			reserved[11];
@@ -642,6 +646,8 @@ struct v4l2_plane {
  *		(or a "cookie" that should be passed to mmap() as offset)
  * @userptr:	for non-multiplanar buffers with memory == V4L2_MEMORY_USERPTR;
  *		a userspace pointer pointing to this buffer
+ * @fd:		for non-multiplanar buffers with memory == V4L2_MEMORY_DMABUF;
+ *		a userspace file descriptor associated with this buffer
  * @planes:	for multiplanar buffers; userspace pointer to the array of plane
  *		info structs for this buffer
  * @length:	size in bytes of the buffer (NOT its payload) for single-plane
@@ -668,6 +674,7 @@ struct v4l2_buffer {
 		__u32           offset;
 		unsigned long   userptr;
 		struct v4l2_plane *planes;
+		__s32		fd;
 	} m;
 	__u32			length;
 	__u32			reserved2;
-- 
1.7.9.5

[PATCHv10 02/26] Documentation: media: description of DMABUF importing in V4L2

[Tomasz Stanislawski]

This patch adds description and usage examples for importing
DMABUF file descriptor in V4L2.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: linux-doc@vger.kernel.org
---
 Documentation/DocBook/media/v4l/compat.xml         |    4 +
 Documentation/DocBook/media/v4l/io.xml             |  181 +++++++++++++++++++-
 .../DocBook/media/v4l/vidioc-create-bufs.xml       |   16 +-
 Documentation/DocBook/media/v4l/vidioc-qbuf.xml    |   17 ++
 Documentation/DocBook/media/v4l/vidioc-reqbufs.xml |   47 ++---
 5 files changed, 235 insertions(+), 30 deletions(-)

diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml
index 4fdf6b5..50eb630 100644
--- a/Documentation/DocBook/media/v4l/compat.xml
+++ b/Documentation/DocBook/media/v4l/compat.xml
@@ -2586,6 +2586,10 @@ ioctls.</para>
 	  <para>Vendor and device specific media bus pixel formats.
 	    <xref linkend="v4l2-mbus-vendor-spec-fmts" />.</para>
         </listitem>
+        <listitem>
+	  <para>Importing DMABUF file descriptors as a new IO method described
+	  in <xref linkend="dmabuf" />.</para>
+        </listitem>
       </itemizedlist>
     </section>
 
diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml
index b5d1cbd..0abb5cb 100644
--- a/Documentation/DocBook/media/v4l/io.xml
+++ b/Documentation/DocBook/media/v4l/io.xml
@@ -331,7 +331,7 @@ application until one or more buffers can be dequeued. By default
 outgoing queue. When the <constant>O_NONBLOCK</constant> flag was
 given to the &func-open; function, <constant>VIDIOC_DQBUF</constant>
 returns immediately with an &EAGAIN; when no buffer is available. The
-&func-select; or &func-poll; function are always available.</para>
+&func-select; or &func-poll; functions are always available.</para>
 
     <para>To start and stop capturing or output applications call the
 &VIDIOC-STREAMON; and &VIDIOC-STREAMOFF; ioctl. Note
@@ -472,6 +472,162 @@ rest should be evident.</para>
       </footnote></para>
   </section>
 
+  <section id="dmabuf">
+    <title>Streaming I/O (DMA buffer importing)</title>
+
+    <note>
+      <title>Experimental</title>
+      <para>This is an <link linkend="experimental"> experimental </link>
+      interface and may change in the future.</para>
+    </note>
+
+<para>The DMABUF framework provides a generic method for sharing buffers
+between multiple devices. Device drivers that support DMABUF can export a DMA
+buffer to userspace as a file descriptor (known as the exporter role), import a
+DMA buffer from userspace using a file descriptor previously exported for a
+different or the same device (known as the importer role), or both. This
+section describes the DMABUF importer role API in V4L2.</para>
+
+<para>Input and output devices support the streaming I/O method when the
+<constant>V4L2_CAP_STREAMING</constant> flag in the
+<structfield>capabilities</structfield> field of &v4l2-capability; returned by
+the &VIDIOC-QUERYCAP; ioctl is set. Whether importing DMA buffers through
+DMABUF file descriptors is supported is determined by calling the
+&VIDIOC-REQBUFS; ioctl with the memory type set to
+<constant>V4L2_MEMORY_DMABUF</constant>.</para>
+
+    <para>This I/O method is dedicated to sharing DMA buffers between different
+devices, which may be V4L devices or other video-related devices (e.g. DRM).
+Buffers (planes) are allocated by a driver on behalf of an application. Next,
+these buffers are exported to the application as file descriptors using an API
+which is specific for an allocator driver.  Only such file descriptor are
+exchanged. The descriptors and meta-information are passed in &v4l2-buffer; (or
+in &v4l2-plane; in the multi-planar API case).  The driver must be switched
+into DMABUF I/O mode by calling the &VIDIOC-REQBUFS; with the desired buffer
+type.</para>
+
+    <example>
+      <title>Initiating streaming I/O with DMABUF file descriptors</title>
+
+      <programlisting>
+&v4l2-requestbuffers; reqbuf;
+
+memset(&amp;reqbuf, 0, sizeof (reqbuf));
+reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+reqbuf.memory = V4L2_MEMORY_DMABUF;
+reqbuf.count = 1;
+
+if (ioctl(fd, &VIDIOC-REQBUFS;, &amp;reqbuf) == -1) {
+	if (errno == EINVAL)
+		printf("Video capturing or DMABUF streaming is not supported\n");
+	else
+		perror("VIDIOC_REQBUFS");
+
+	exit(EXIT_FAILURE);
+}
+      </programlisting>
+    </example>
+
+    <para>The buffer (plane) file descriptor is passed on the fly with the
+&VIDIOC-QBUF; ioctl. In case of multiplanar buffers, every plane can be
+associated with a different DMABUF descriptor. Although buffers are commonly
+cycled, applications can pass a different DMABUF descriptor at each
+<constant>VIDIOC_QBUF</constant> call.</para>
+
+    <example>
+      <title>Queueing DMABUF using single plane API</title>
+
+      <programlisting>
+int buffer_queue(int v4lfd, int index, int dmafd)
+{
+	&v4l2-buffer; buf;
+
+	memset(&amp;buf, 0, sizeof buf);
+	buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	buf.memory = V4L2_MEMORY_DMABUF;
+	buf.index = index;
+	buf.m.fd = dmafd;
+
+	if (ioctl(v4lfd, &VIDIOC-QBUF;, &amp;buf) == -1) {
+		perror("VIDIOC_QBUF");
+		return -1;
+	}
+
+	return 0;
+}
+      </programlisting>
+    </example>
+
+    <example>
+      <title>Queueing DMABUF using multi plane API</title>
+
+      <programlisting>
+int buffer_queue_mp(int v4lfd, int index, int dmafd[], int n_planes)
+{
+	&v4l2-buffer; buf;
+	&v4l2-plane; planes[VIDEO_MAX_PLANES];
+	int i;
+
+	memset(&amp;buf, 0, sizeof buf);
+	buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+	buf.memory = V4L2_MEMORY_DMABUF;
+	buf.index = index;
+	buf.m.planes = planes;
+	buf.length = n_planes;
+
+	memset(&amp;planes, 0, sizeof planes);
+
+	for (i = 0; i &lt; n_planes; ++i)
+		buf.m.planes[i].m.fd = dmafd[i];
+
+	if (ioctl(v4lfd, &VIDIOC-QBUF;, &amp;buf) == -1) {
+		perror("VIDIOC_QBUF");
+		return -1;
+	}
+
+	return 0;
+}
+      </programlisting>
+    </example>
+
+    <para>Captured or displayed buffers are dequeued with the
+&VIDIOC-DQBUF; ioctl. The driver can unlock the buffer at any
+time between the completion of the DMA and this ioctl. The memory is
+also unlocked when &VIDIOC-STREAMOFF; is called, &VIDIOC-REQBUFS;, or
+when the device is closed.</para>
+
+    <para>For capturing applications it is customary to enqueue a
+number of empty buffers, to start capturing and enter the read loop.
+Here the application waits until a filled buffer can be dequeued, and
+re-enqueues the buffer when the data is no longer needed. Output
+applications fill and enqueue buffers, when enough buffers are stacked
+up output is started. In the write loop, when the application
+runs out of free buffers it must wait until an empty buffer can be
+dequeued and reused. Two methods exist to suspend execution of the
+application until one or more buffers can be dequeued. By default
+<constant>VIDIOC_DQBUF</constant> blocks when no buffer is in the
+outgoing queue. When the <constant>O_NONBLOCK</constant> flag was
+given to the &func-open; function, <constant>VIDIOC_DQBUF</constant>
+returns immediately with an &EAGAIN; when no buffer is available. The
+&func-select; and &func-poll; functions are always available.</para>
+
+    <para>To start and stop capturing or displaying applications call the
+&VIDIOC-STREAMON; and &VIDIOC-STREAMOFF; ioctls. Note that
+<constant>VIDIOC_STREAMOFF</constant> removes all buffers from both queues and
+unlocks all buffers as a side effect. Since there is no notion of doing
+anything "now" on a multitasking system, if an application needs to synchronize
+with another event it should examine the &v4l2-buffer;
+<structfield>timestamp</structfield> of captured buffers, or set the field
+before enqueuing buffers for output.</para>
+
+    <para>Drivers implementing DMABUF importing I/O must support the
+<constant>VIDIOC_REQBUFS</constant>, <constant>VIDIOC_QBUF</constant>,
+<constant>VIDIOC_DQBUF</constant>, <constant>VIDIOC_STREAMON</constant> and
+<constant>VIDIOC_STREAMOFF</constant> ioctls, and the
+<function>select()</function> and <function>poll()</function> functions.</para>
+
+  </section>
+
   <section id="async">
     <title>Asynchronous I/O</title>
 
@@ -673,6 +829,14 @@ memory, set by the application. See <xref linkend="userp" /> for details.
 	    <structname>v4l2_buffer</structname> structure.</entry>
 	  </row>
 	  <row>
+	    <entry></entry>
+	    <entry>int</entry>
+	    <entry><structfield>fd</structfield></entry>
+	    <entry>For the single-plane API and when
+<structfield>memory</structfield> is <constant>V4L2_MEMORY_DMABUF</constant> this
+is the file descriptor associated with a DMABUF buffer.</entry>
+	  </row>
+	  <row>
 	    <entry>__u32</entry>
 	    <entry><structfield>length</structfield></entry>
 	    <entry></entry>
@@ -744,6 +908,15 @@ should set this to 0.</entry>
 	      </entry>
 	  </row>
 	  <row>
+	    <entry></entry>
+	    <entry>int</entry>
+	    <entry><structfield>fd</structfield></entry>
+	    <entry>When the memory type in the containing &v4l2-buffer; is
+		<constant>V4L2_MEMORY_DMABUF</constant>, this is a file
+		descriptor associated with a DMABUF buffer, similar to the
+		<structfield>fd</structfield> field in &v4l2-buffer;.</entry>
+	  </row>
+	  <row>
 	    <entry>__u32</entry>
 	    <entry><structfield>data_offset</structfield></entry>
 	    <entry></entry>
@@ -964,6 +1137,12 @@ pointer</link> I/O.</entry>
 	    <entry>3</entry>
 	    <entry>[to do]</entry>
 	  </row>
+	  <row>
+	    <entry><constant>V4L2_MEMORY_DMABUF</constant></entry>
+	    <entry>4</entry>
+	    <entry>The buffer is used for <link linkend="dmabuf">DMA shared
+buffer</link> I/O.</entry>
+	  </row>
 	</tbody>
       </tgroup>
     </table>
diff --git a/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml b/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml
index a8cda1a..cd99436 100644
--- a/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml
@@ -6,7 +6,8 @@
 
   <refnamediv>
     <refname>VIDIOC_CREATE_BUFS</refname>
-    <refpurpose>Create buffers for Memory Mapped or User Pointer I/O</refpurpose>
+    <refpurpose>Create buffers for Memory Mapped or User Pointer or DMA Buffer
+    I/O</refpurpose>
   </refnamediv>
 
   <refsynopsisdiv>
@@ -55,11 +56,11 @@
     </note>
 
     <para>This ioctl is used to create buffers for <link linkend="mmap">memory
-mapped</link> or <link linkend="userp">user pointer</link>
-I/O. It can be used as an alternative or in addition to the
-<constant>VIDIOC_REQBUFS</constant> ioctl, when a tighter control over buffers
-is required. This ioctl can be called multiple times to create buffers of
-different sizes.</para>
+mapped</link> or <link linkend="userp">user pointer</link> or <link
+linkend="dmabuf">DMA buffer</link> I/O. It can be used as an alternative or in
+addition to the <constant>VIDIOC_REQBUFS</constant> ioctl, when a tighter
+control over buffers is required. This ioctl can be called multiple times to
+create buffers of different sizes.</para>
 
     <para>To allocate device buffers applications initialize relevant fields of
 the <structname>v4l2_create_buffers</structname> structure. They set the
@@ -109,7 +110,8 @@ information.</para>
 	    <entry>__u32</entry>
 	    <entry><structfield>memory</structfield></entry>
 	    <entry>Applications set this field to
-<constant>V4L2_MEMORY_MMAP</constant> or
+<constant>V4L2_MEMORY_MMAP</constant>,
+<constant>V4L2_MEMORY_DMABUF</constant> or
 <constant>V4L2_MEMORY_USERPTR</constant>. See <xref linkend="v4l2-memory"
 /></entry>
 	  </row>
diff --git a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml
index 2d37abe..3504a7f 100644
--- a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml
@@ -109,6 +109,23 @@ they cannot be swapped out to disk. Buffers remain locked until
 dequeued, until the &VIDIOC-STREAMOFF; or &VIDIOC-REQBUFS; ioctl is
 called, or until the device is closed.</para>
 
+    <para>To enqueue a <link linkend="dmabuf">DMABUF</link> buffer applications
+set the <structfield>memory</structfield> field to
+<constant>V4L2_MEMORY_DMABUF</constant> and the <structfield>m.fd</structfield>
+field to a file descriptor associated with a DMABUF buffer. When the
+multi-planar API is used the <structfield>m.fd</structfield> fields of the
+passed array of &v4l2-plane; have to be used instead. When
+<constant>VIDIOC_QBUF</constant> is called with a pointer to this structure the
+driver sets the <constant>V4L2_BUF_FLAG_QUEUED</constant> flag and clears the
+<constant>V4L2_BUF_FLAG_MAPPED</constant> and
+<constant>V4L2_BUF_FLAG_DONE</constant> flags in the
+<structfield>flags</structfield> field, or it returns an error code.  This
+ioctl locks the buffer. Locking a buffer means passing it to a driver for a
+hardware access (usually DMA).  If an application accesses (reads/writes) a
+locked buffer then the result is undefined.  Buffers remain locked until
+dequeued, until the &VIDIOC-STREAMOFF; or &VIDIOC-REQBUFS; ioctl is called, or
+until the device is closed.</para>
+
     <para>Applications call the <constant>VIDIOC_DQBUF</constant>
 ioctl to dequeue a filled (capturing) or displayed (output) buffer
 from the driver's outgoing queue. They just set the
diff --git a/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml b/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml
index 2b50ef2..78a06a9 100644
--- a/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml
@@ -48,28 +48,30 @@
   <refsect1>
     <title>Description</title>
 
-    <para>This ioctl is used to initiate <link linkend="mmap">memory
-mapped</link> or <link linkend="userp">user pointer</link>
-I/O. Memory mapped buffers are located in device memory and must be
-allocated with this ioctl before they can be mapped into the
-application's address space. User buffers are allocated by
-applications themselves, and this ioctl is merely used to switch the
-driver into user pointer I/O mode and to setup some internal structures.</para>
+<para>This ioctl is used to initiate <link linkend="mmap">memory mapped</link>,
+<link linkend="userp">user pointer</link> or <link
+linkend="dmabuf">DMABUF</link> based I/O.  Memory mapped buffers are located in
+device memory and must be allocated with this ioctl before they can be mapped
+into the application's address space. User buffers are allocated by
+applications themselves, and this ioctl is merely used to switch the driver
+into user pointer I/O mode and to setup some internal structures.
+Similarly, DMABUF buffers are allocated by applications through a device
+driver, and this ioctl only configures the driver into DMABUF I/O mode without
+performing any direct allocation.</para>
 
-    <para>To allocate device buffers applications initialize all
-fields of the <structname>v4l2_requestbuffers</structname> structure.
-They set the <structfield>type</structfield> field to the respective
-stream or buffer type, the <structfield>count</structfield> field to
-the desired number of buffers, <structfield>memory</structfield>
-must be set to the requested I/O method and the <structfield>reserved</structfield> array
-must be zeroed. When the ioctl
-is called with a pointer to this structure the driver will attempt to allocate
-the requested number of buffers and it stores the actual number
-allocated in the <structfield>count</structfield> field. It can be
-smaller than the number requested, even zero, when the driver runs out
-of free memory. A larger number is also possible when the driver requires
-more buffers to function correctly. For example video output requires at least two buffers,
-one displayed and one filled by the application.</para>
+    <para>To allocate device buffers applications initialize all fields of the
+<structname>v4l2_requestbuffers</structname> structure.  They set the
+<structfield>type</structfield> field to the respective stream or buffer type,
+the <structfield>count</structfield> field to the desired number of buffers,
+<structfield>memory</structfield> must be set to the requested I/O method and
+the <structfield>reserved</structfield> array must be zeroed. When the ioctl is
+called with a pointer to this structure the driver will attempt to allocate the
+requested number of buffers and it stores the actual number allocated in the
+<structfield>count</structfield> field. It can be smaller than the number
+requested, even zero, when the driver runs out of free memory. A larger number
+is also possible when the driver requires more buffers to function correctly.
+For example video output requires at least two buffers, one displayed and one
+filled by the application.</para>
     <para>When the I/O method is not supported the ioctl
 returns an &EINVAL;.</para>
 
@@ -102,7 +104,8 @@ as the &v4l2-format; <structfield>type</structfield> field. See <xref
 	    <entry>__u32</entry>
 	    <entry><structfield>memory</structfield></entry>
 	    <entry>Applications set this field to
-<constant>V4L2_MEMORY_MMAP</constant> or
+<constant>V4L2_MEMORY_MMAP</constant>,
+<constant>V4L2_MEMORY_DMABUF</constant> or
 <constant>V4L2_MEMORY_USERPTR</constant>. See <xref linkend="v4l2-memory"
 />.</entry>
 	  </row>
-- 
1.7.9.5

[PATCHv10 03/26] v4l: vb2: add support for shared buffer (dma_buf)

[Tomasz Stanislawski]

From: Sumit Semwal <sumit.semwal@ti.com>

This patch adds support for DMABUF memory type in videobuf2. It calls relevant
APIs of dma_buf for v4l reqbuf / qbuf / dqbuf operations.

For this version, the support is for videobuf2 as a user of the shared buffer;
so the allocation of the buffer is done outside of V4L2. [A sample allocator of
dma-buf shared buffer is given at [1]]

[1]: Rob Clark's DRM:
   https://github.com/robclark/kernel-omap4/commits/drmplane-dmabuf

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
   [original work in the PoC for buffer sharing]
Signed-off-by: Sumit Semwal <sumit.semwal@ti.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/Kconfig          |    1 +
 drivers/media/v4l2-core/videobuf2-core.c |  206 +++++++++++++++++++++++++++++-
 include/media/videobuf2-core.h           |   27 ++++
 3 files changed, 231 insertions(+), 3 deletions(-)

diff --git a/drivers/media/v4l2-core/Kconfig b/drivers/media/v4l2-core/Kconfig
index 0c54e19..2e787cc 100644
--- a/drivers/media/v4l2-core/Kconfig
+++ b/drivers/media/v4l2-core/Kconfig
@@ -59,6 +59,7 @@ config VIDEOBUF_DVB
 
 # Used by drivers that need Videobuf2 modules
 config VIDEOBUF2_CORE
+	select DMA_SHARED_BUFFER
 	tristate
 
 config VIDEOBUF2_MEMOPS
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 432df11..a51dad6 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -109,6 +109,36 @@ static void __vb2_buf_userptr_put(struct vb2_buffer *vb)
 }
 
 /**
+ * __vb2_plane_dmabuf_put() - release memory associated with
+ * a DMABUF shared plane
+ */
+static void __vb2_plane_dmabuf_put(struct vb2_queue *q, struct vb2_plane *p)
+{
+	if (!p->mem_priv)
+		return;
+
+	if (p->dbuf_mapped)
+		call_memop(q, unmap_dmabuf, p->mem_priv);
+
+	call_memop(q, detach_dmabuf, p->mem_priv);
+	dma_buf_put(p->dbuf);
+	memset(p, 0, sizeof(*p));
+}
+
+/**
+ * __vb2_buf_dmabuf_put() - release memory associated with
+ * a DMABUF shared buffer
+ */
+static void __vb2_buf_dmabuf_put(struct vb2_buffer *vb)
+{
+	struct vb2_queue *q = vb->vb2_queue;
+	unsigned int plane;
+
+	for (plane = 0; plane < vb->num_planes; ++plane)
+		__vb2_plane_dmabuf_put(q, &vb->planes[plane]);
+}
+
+/**
  * __setup_offsets() - setup unique offsets ("cookies") for every plane in
  * every buffer on the queue
  */
@@ -230,6 +260,8 @@ static void __vb2_free_mem(struct vb2_queue *q, unsigned int buffers)
 		/* Free MMAP buffers or release USERPTR buffers */
 		if (q->memory == V4L2_MEMORY_MMAP)
 			__vb2_buf_mem_free(vb);
+		else if (q->memory == V4L2_MEMORY_DMABUF)
+			__vb2_buf_dmabuf_put(vb);
 		else
 			__vb2_buf_userptr_put(vb);
 	}
@@ -362,6 +394,8 @@ static void __fill_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b)
 			b->m.offset = vb->v4l2_planes[0].m.mem_offset;
 		else if (q->memory == V4L2_MEMORY_USERPTR)
 			b->m.userptr = vb->v4l2_planes[0].m.userptr;
+		else if (q->memory == V4L2_MEMORY_DMABUF)
+			b->m.fd = vb->v4l2_planes[0].m.fd;
 	}
 
 	/*
@@ -454,13 +488,28 @@ static int __verify_mmap_ops(struct vb2_queue *q)
 }
 
 /**
+ * __verify_dmabuf_ops() - verify that all memory operations required for
+ * DMABUF queue type have been provided
+ */
+static int __verify_dmabuf_ops(struct vb2_queue *q)
+{
+	if (!(q->io_modes & VB2_DMABUF) || !q->mem_ops->attach_dmabuf ||
+	    !q->mem_ops->detach_dmabuf  || !q->mem_ops->map_dmabuf ||
+	    !q->mem_ops->unmap_dmabuf)
+		return -EINVAL;
+
+	return 0;
+}
+
+/**
  * __verify_memory_type() - Check whether the memory type and buffer type
  * passed to a buffer operation are compatible with the queue.
  */
 static int __verify_memory_type(struct vb2_queue *q,
 		enum v4l2_memory memory, enum v4l2_buf_type type)
 {
-	if (memory != V4L2_MEMORY_MMAP && memory != V4L2_MEMORY_USERPTR) {
+	if (memory != V4L2_MEMORY_MMAP && memory != V4L2_MEMORY_USERPTR &&
+	    memory != V4L2_MEMORY_DMABUF) {
 		dprintk(1, "reqbufs: unsupported memory type\n");
 		return -EINVAL;
 	}
@@ -484,6 +533,11 @@ static int __verify_memory_type(struct vb2_queue *q,
 		return -EINVAL;
 	}
 
+	if (memory == V4L2_MEMORY_DMABUF && __verify_dmabuf_ops(q)) {
+		dprintk(1, "reqbufs: DMABUF for current setup unsupported\n");
+		return -EINVAL;
+	}
+
 	/*
 	 * Place the busy tests at the end: -EBUSY can be ignored when
 	 * create_bufs is called with count == 0, but count == 0 should still
@@ -845,6 +899,16 @@ static void __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b
 					b->m.planes[plane].length;
 			}
 		}
+		if (b->memory == V4L2_MEMORY_DMABUF) {
+			for (plane = 0; plane < vb->num_planes; ++plane) {
+				v4l2_planes[plane].m.fd =
+					b->m.planes[plane].m.fd;
+				v4l2_planes[plane].length =
+					b->m.planes[plane].length;
+				v4l2_planes[plane].data_offset =
+					b->m.planes[plane].data_offset;
+			}
+		}
 	} else {
 		/*
 		 * Single-planar buffers do not use planes array,
@@ -859,6 +923,13 @@ static void __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b
 			v4l2_planes[0].m.userptr = b->m.userptr;
 			v4l2_planes[0].length = b->length;
 		}
+
+		if (b->memory == V4L2_MEMORY_DMABUF) {
+			v4l2_planes[0].m.fd = b->m.fd;
+			v4l2_planes[0].length = b->length;
+			v4l2_planes[0].data_offset = 0;
+		}
+
 	}
 
 	vb->v4l2_buf.field = b->field;
@@ -959,6 +1030,107 @@ static int __qbuf_mmap(struct vb2_buffer *vb, const struct v4l2_buffer *b)
 }
 
 /**
+ * __qbuf_dmabuf() - handle qbuf of a DMABUF buffer
+ */
+static int __qbuf_dmabuf(struct vb2_buffer *vb, const struct v4l2_buffer *b)
+{
+	struct v4l2_plane planes[VIDEO_MAX_PLANES];
+	struct vb2_queue *q = vb->vb2_queue;
+	void *mem_priv;
+	unsigned int plane;
+	int ret;
+	int write = !V4L2_TYPE_IS_OUTPUT(q->type);
+
+	/* Verify and copy relevant information provided by the userspace */
+	__fill_vb2_buffer(vb, b, planes);
+
+	for (plane = 0; plane < vb->num_planes; ++plane) {
+		struct dma_buf *dbuf = dma_buf_get(planes[plane].m.fd);
+
+		if (IS_ERR_OR_NULL(dbuf)) {
+			dprintk(1, "qbuf: invalid dmabuf fd for plane %d\n",
+				plane);
+			ret = -EINVAL;
+			goto err;
+		}
+
+		/* use DMABUF size if length is not provided */
+		if (planes[plane].length == 0)
+			planes[plane].length = dbuf->size;
+
+		if (planes[plane].length < planes[plane].data_offset +
+		    q->plane_sizes[plane]) {
+			ret = -EINVAL;
+			goto err;
+		}
+
+		/* Skip the plane if already verified */
+		if (dbuf == vb->planes[plane].dbuf &&
+		    vb->v4l2_planes[plane].length == planes[plane].length) {
+			dma_buf_put(dbuf);
+			continue;
+		}
+
+		dprintk(1, "qbuf: buffer for plane %d changed\n", plane);
+
+		/* Release previously acquired memory if present */
+		__vb2_plane_dmabuf_put(q, &vb->planes[plane]);
+		memset(&vb->v4l2_planes[plane], 0, sizeof(struct v4l2_plane));
+
+		/* Acquire each plane's memory */
+		mem_priv = call_memop(q, attach_dmabuf, q->alloc_ctx[plane],
+			dbuf, planes[plane].length, write);
+		if (IS_ERR(mem_priv)) {
+			dprintk(1, "qbuf: failed to attach dmabuf\n");
+			ret = PTR_ERR(mem_priv);
+			dma_buf_put(dbuf);
+			goto err;
+		}
+
+		vb->planes[plane].dbuf = dbuf;
+		vb->planes[plane].mem_priv = mem_priv;
+	}
+
+	/* TODO: This pins the buffer(s) with  dma_buf_map_attachment()).. but
+	 * really we want to do this just before the DMA, not while queueing
+	 * the buffer(s)..
+	 */
+	for (plane = 0; plane < vb->num_planes; ++plane) {
+		ret = call_memop(q, map_dmabuf, vb->planes[plane].mem_priv);
+		if (ret) {
+			dprintk(1, "qbuf: failed to map dmabuf for plane %d\n",
+				plane);
+			goto err;
+		}
+		vb->planes[plane].dbuf_mapped = 1;
+	}
+
+	/*
+	 * Call driver-specific initialization on the newly acquired buffer,
+	 * if provided.
+	 */
+	ret = call_qop(q, buf_init, vb);
+	if (ret) {
+		dprintk(1, "qbuf: buffer initialization failed\n");
+		goto err;
+	}
+
+	/*
+	 * Now that everything is in order, copy relevant information
+	 * provided by userspace.
+	 */
+	for (plane = 0; plane < vb->num_planes; ++plane)
+		vb->v4l2_planes[plane] = planes[plane];
+
+	return 0;
+err:
+	/* In case of errors, release planes that were already acquired */
+	__vb2_buf_dmabuf_put(vb);
+
+	return ret;
+}
+
+/**
  * __enqueue_in_driver() - enqueue a vb2_buffer in driver for processing
  */
 static void __enqueue_in_driver(struct vb2_buffer *vb)
@@ -982,6 +1154,9 @@ static int __buf_prepare(struct vb2_buffer *vb, const struct v4l2_buffer *b)
 	case V4L2_MEMORY_USERPTR:
 		ret = __qbuf_userptr(vb, b);
 		break;
+	case V4L2_MEMORY_DMABUF:
+		ret = __qbuf_dmabuf(vb, b);
+		break;
 	default:
 		WARN(1, "Invalid queue type\n");
 		ret = -EINVAL;
@@ -1303,6 +1478,30 @@ int vb2_wait_for_all_buffers(struct vb2_queue *q)
 EXPORT_SYMBOL_GPL(vb2_wait_for_all_buffers);
 
 /**
+ * __vb2_dqbuf() - bring back the buffer to the DEQUEUED state
+ */
+static void __vb2_dqbuf(struct vb2_buffer *vb)
+{
+	struct vb2_queue *q = vb->vb2_queue;
+	unsigned int i;
+
+	/* nothing to do if the buffer is already dequeued */
+	if (vb->state == VB2_BUF_STATE_DEQUEUED)
+		return;
+
+	vb->state = VB2_BUF_STATE_DEQUEUED;
+
+	/* unmap DMABUF buffer */
+	if (q->memory == V4L2_MEMORY_DMABUF)
+		for (i = 0; i < vb->num_planes; ++i) {
+			if (!vb->planes[i].dbuf_mapped)
+				continue;
+			call_memop(q, unmap_dmabuf, vb->planes[i].mem_priv);
+			vb->planes[i].dbuf_mapped = 0;
+		}
+}
+
+/**
  * vb2_dqbuf() - Dequeue a buffer to the userspace
  * @q:		videobuf2 queue
  * @b:		buffer structure passed from userspace to vidioc_dqbuf handler
@@ -1363,11 +1562,12 @@ int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking)
 	__fill_v4l2_buffer(vb, b);
 	/* Remove from videobuf queue */
 	list_del(&vb->queued_entry);
+	/* go back to dequeued state */
+	__vb2_dqbuf(vb);
 
 	dprintk(1, "dqbuf of buffer %d, with state %d\n",
 			vb->v4l2_buf.index, vb->state);
 
-	vb->state = VB2_BUF_STATE_DEQUEUED;
 	return 0;
 }
 EXPORT_SYMBOL_GPL(vb2_dqbuf);
@@ -1406,7 +1606,7 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
 	 * Reinitialize all buffers for next use.
 	 */
 	for (i = 0; i < q->num_buffers; ++i)
-		q->bufs[i]->state = VB2_BUF_STATE_DEQUEUED;
+		__vb2_dqbuf(q->bufs[i]);
 }
 
 /**
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index e04252a..689ae4a 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -16,6 +16,7 @@
 #include <linux/mutex.h>
 #include <linux/poll.h>
 #include <linux/videodev2.h>
+#include <linux/dma-buf.h>
 
 struct vb2_alloc_ctx;
 struct vb2_fileio_data;
@@ -41,6 +42,20 @@ struct vb2_fileio_data;
  *		 argument to other ops in this structure
  * @put_userptr: inform the allocator that a USERPTR buffer will no longer
  *		 be used
+ * @attach_dmabuf: attach a shared struct dma_buf for a hardware operation;
+ *		   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;
+ *		   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
+ *		   allocator private per-buffer structure previously returned
+ *		   from the attach_dmabuf callback
+ * @map_dmabuf: request for access to the dmabuf from allocator; the allocator
+ *		of dmabuf is informed that this driver is going to use the
+ *		dmabuf
+ * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
+ *		  that this driver is done using the dmabuf for now
  * @vaddr:	return a kernel virtual address to a given memory buffer
  *		associated with the passed private structure or NULL if no
  *		such mapping exists
@@ -56,6 +71,8 @@ struct vb2_fileio_data;
  * Required ops for USERPTR types: get_userptr, put_userptr.
  * Required ops for MMAP types: alloc, put, num_users, mmap.
  * Required ops for read/write access types: alloc, put, num_users, vaddr
+ * Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, map_dmabuf,
+ *				  unmap_dmabuf.
  */
 struct vb2_mem_ops {
 	void		*(*alloc)(void *alloc_ctx, unsigned long size);
@@ -65,6 +82,12 @@ struct vb2_mem_ops {
 					unsigned long size, int write);
 	void		(*put_userptr)(void *buf_priv);
 
+	void		*(*attach_dmabuf)(void *alloc_ctx, struct dma_buf *dbuf,
+				unsigned long size, int write);
+	void		(*detach_dmabuf)(void *buf_priv);
+	int		(*map_dmabuf)(void *buf_priv);
+	void		(*unmap_dmabuf)(void *buf_priv);
+
 	void		*(*vaddr)(void *buf_priv);
 	void		*(*cookie)(void *buf_priv);
 
@@ -75,6 +98,8 @@ struct vb2_mem_ops {
 
 struct vb2_plane {
 	void			*mem_priv;
+	struct dma_buf		*dbuf;
+	unsigned int		dbuf_mapped;
 };
 
 /**
@@ -83,12 +108,14 @@ struct vb2_plane {
  * @VB2_USERPTR:	driver supports USERPTR with streaming API
  * @VB2_READ:		driver supports read() style access
  * @VB2_WRITE:		driver supports write() style access
+ * @VB2_DMABUF:		driver supports DMABUF with streaming API
  */
 enum vb2_io_modes {
 	VB2_MMAP	= (1 << 0),
 	VB2_USERPTR	= (1 << 1),
 	VB2_READ	= (1 << 2),
 	VB2_WRITE	= (1 << 3),
+	VB2_DMABUF	= (1 << 4),
 };
 
 /**
-- 
1.7.9.5

[PATCHv10 04/26] v4l: vb: remove warnings about MEMORY_DMABUF

[Tomasz Stanislawski]

From: Sumit Semwal <sumit.semwal@ti.com>

Adding DMABUF memory type causes videobuf to complain about not using it
in some switch cases. This patch removes these warnings.

Signed-off-by: Sumit Semwal <sumit.semwal@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/videobuf-core.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/media/v4l2-core/videobuf-core.c b/drivers/media/v4l2-core/videobuf-core.c
index bf7a326..5449e8a 100644
--- a/drivers/media/v4l2-core/videobuf-core.c
+++ b/drivers/media/v4l2-core/videobuf-core.c
@@ -335,6 +335,9 @@ static void videobuf_status(struct videobuf_queue *q, struct v4l2_buffer *b,
 	case V4L2_MEMORY_OVERLAY:
 		b->m.offset  = vb->boff;
 		break;
+	case V4L2_MEMORY_DMABUF:
+		/* DMABUF is not handled in videobuf framework */
+		break;
 	}
 
 	b->flags    = 0;
@@ -405,6 +408,7 @@ int __videobuf_mmap_setup(struct videobuf_queue *q,
 			break;
 		case V4L2_MEMORY_USERPTR:
 		case V4L2_MEMORY_OVERLAY:
+		case V4L2_MEMORY_DMABUF:
 			/* nothing */
 			break;
 		}
-- 
1.7.9.5

[PATCHv10 05/26] v4l: vb2-dma-contig: shorten vb2_dma_contig prefix to vb2_dc

[Tomasz Stanislawski]

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/videobuf2-dma-contig.c |   36 ++++++++++++------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 4b71326..a05784f 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -32,9 +32,9 @@ struct vb2_dc_buf {
 	struct vb2_vmarea_handler	handler;
 };
 
-static void vb2_dma_contig_put(void *buf_priv);
+static void vb2_dc_put(void *buf_priv);
 
-static void *vb2_dma_contig_alloc(void *alloc_ctx, unsigned long size)
+static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size)
 {
 	struct vb2_dc_conf *conf = alloc_ctx;
 	struct vb2_dc_buf *buf;
@@ -56,7 +56,7 @@ static void *vb2_dma_contig_alloc(void *alloc_ctx, unsigned long size)
 	buf->size = size;
 
 	buf->handler.refcount = &buf->refcount;
-	buf->handler.put = vb2_dma_contig_put;
+	buf->handler.put = vb2_dc_put;
 	buf->handler.arg = buf;
 
 	atomic_inc(&buf->refcount);
@@ -64,7 +64,7 @@ static void *vb2_dma_contig_alloc(void *alloc_ctx, unsigned long size)
 	return buf;
 }
 
-static void vb2_dma_contig_put(void *buf_priv)
+static void vb2_dc_put(void *buf_priv)
 {
 	struct vb2_dc_buf *buf = buf_priv;
 
@@ -75,14 +75,14 @@ static void vb2_dma_contig_put(void *buf_priv)
 	}
 }
 
-static void *vb2_dma_contig_cookie(void *buf_priv)
+static void *vb2_dc_cookie(void *buf_priv)
 {
 	struct vb2_dc_buf *buf = buf_priv;
 
 	return &buf->dma_addr;
 }
 
-static void *vb2_dma_contig_vaddr(void *buf_priv)
+static void *vb2_dc_vaddr(void *buf_priv)
 {
 	struct vb2_dc_buf *buf = buf_priv;
 	if (!buf)
@@ -91,14 +91,14 @@ static void *vb2_dma_contig_vaddr(void *buf_priv)
 	return buf->vaddr;
 }
 
-static unsigned int vb2_dma_contig_num_users(void *buf_priv)
+static unsigned int vb2_dc_num_users(void *buf_priv)
 {
 	struct vb2_dc_buf *buf = buf_priv;
 
 	return atomic_read(&buf->refcount);
 }
 
-static int vb2_dma_contig_mmap(void *buf_priv, struct vm_area_struct *vma)
+static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
 {
 	struct vb2_dc_buf *buf = buf_priv;
 
@@ -111,7 +111,7 @@ static int vb2_dma_contig_mmap(void *buf_priv, struct vm_area_struct *vma)
 				  &vb2_common_vm_ops, &buf->handler);
 }
 
-static void *vb2_dma_contig_get_userptr(void *alloc_ctx, unsigned long vaddr,
+static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
 					unsigned long size, int write)
 {
 	struct vb2_dc_buf *buf;
@@ -138,7 +138,7 @@ static void *vb2_dma_contig_get_userptr(void *alloc_ctx, unsigned long vaddr,
 	return buf;
 }
 
-static void vb2_dma_contig_put_userptr(void *mem_priv)
+static void vb2_dc_put_userptr(void *mem_priv)
 {
 	struct vb2_dc_buf *buf = mem_priv;
 
@@ -150,14 +150,14 @@ static void vb2_dma_contig_put_userptr(void *mem_priv)
 }
 
 const struct vb2_mem_ops vb2_dma_contig_memops = {
-	.alloc		= vb2_dma_contig_alloc,
-	.put		= vb2_dma_contig_put,
-	.cookie		= vb2_dma_contig_cookie,
-	.vaddr		= vb2_dma_contig_vaddr,
-	.mmap		= vb2_dma_contig_mmap,
-	.get_userptr	= vb2_dma_contig_get_userptr,
-	.put_userptr	= vb2_dma_contig_put_userptr,
-	.num_users	= vb2_dma_contig_num_users,
+	.alloc		= vb2_dc_alloc,
+	.put		= vb2_dc_put,
+	.cookie		= vb2_dc_cookie,
+	.vaddr		= vb2_dc_vaddr,
+	.mmap		= vb2_dc_mmap,
+	.get_userptr	= vb2_dc_get_userptr,
+	.put_userptr	= vb2_dc_put_userptr,
+	.num_users	= vb2_dc_num_users,
 };
 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
 
-- 
1.7.9.5

[PATCHv10 06/26] v4l: vb2-dma-contig: remove reference of alloc_ctx from a buffer

[Tomasz Stanislawski]

This patch removes a reference to alloc_ctx from an instance of a DMA
contiguous buffer. It helps to avoid a risk of a dangling pointer if the
context is released while the buffer is still valid. Moreover it removes one
dereference step while accessing a device structure.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/videobuf2-dma-contig.c |   13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index a05784f..20c95da 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -23,7 +23,7 @@ struct vb2_dc_conf {
 };
 
 struct vb2_dc_buf {
-	struct vb2_dc_conf		*conf;
+	struct device			*dev;
 	void				*vaddr;
 	dma_addr_t			dma_addr;
 	unsigned long			size;
@@ -37,22 +37,21 @@ static void vb2_dc_put(void *buf_priv);
 static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size)
 {
 	struct vb2_dc_conf *conf = alloc_ctx;
+	struct device *dev = conf->dev;
 	struct vb2_dc_buf *buf;
 
 	buf = kzalloc(sizeof *buf, GFP_KERNEL);
 	if (!buf)
 		return ERR_PTR(-ENOMEM);
 
-	buf->vaddr = dma_alloc_coherent(conf->dev, size, &buf->dma_addr,
-					GFP_KERNEL);
+	buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr, GFP_KERNEL);
 	if (!buf->vaddr) {
-		dev_err(conf->dev, "dma_alloc_coherent of size %ld failed\n",
-			size);
+		dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
 		kfree(buf);
 		return ERR_PTR(-ENOMEM);
 	}
 
-	buf->conf = conf;
+	buf->dev = dev;
 	buf->size = size;
 
 	buf->handler.refcount = &buf->refcount;
@@ -69,7 +68,7 @@ static void vb2_dc_put(void *buf_priv)
 	struct vb2_dc_buf *buf = buf_priv;
 
 	if (atomic_dec_and_test(&buf->refcount)) {
-		dma_free_coherent(buf->conf->dev, buf->size, buf->vaddr,
+		dma_free_coherent(buf->dev, buf->size, buf->vaddr,
 				  buf->dma_addr);
 		kfree(buf);
 	}
-- 
1.7.9.5

[PATCHv10 07/26] v4l: vb2-dma-contig: reorder functions

[Tomasz Stanislawski]

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Group functions by buffer type.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/videobuf2-dma-contig.c |   92 ++++++++++++++----------
 1 file changed, 54 insertions(+), 38 deletions(-)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 20c95da..daac2b2 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -25,14 +25,56 @@ struct vb2_dc_conf {
 struct vb2_dc_buf {
 	struct device			*dev;
 	void				*vaddr;
-	dma_addr_t			dma_addr;
 	unsigned long			size;
-	struct vm_area_struct		*vma;
-	atomic_t			refcount;
+	dma_addr_t			dma_addr;
+
+	/* MMAP related */
 	struct vb2_vmarea_handler	handler;
+	atomic_t			refcount;
+
+	/* USERPTR related */
+	struct vm_area_struct		*vma;
 };
 
-static void vb2_dc_put(void *buf_priv);
+/*********************************************/
+/*         callbacks for all buffers         */
+/*********************************************/
+
+static void *vb2_dc_cookie(void *buf_priv)
+{
+	struct vb2_dc_buf *buf = buf_priv;
+
+	return &buf->dma_addr;
+}
+
+static void *vb2_dc_vaddr(void *buf_priv)
+{
+	struct vb2_dc_buf *buf = buf_priv;
+
+	return buf->vaddr;
+}
+
+static unsigned int vb2_dc_num_users(void *buf_priv)
+{
+	struct vb2_dc_buf *buf = buf_priv;
+
+	return atomic_read(&buf->refcount);
+}
+
+/*********************************************/
+/*        callbacks for MMAP buffers         */
+/*********************************************/
+
+static void vb2_dc_put(void *buf_priv)
+{
+	struct vb2_dc_buf *buf = buf_priv;
+
+	if (!atomic_dec_and_test(&buf->refcount))
+		return;
+
+	dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
+	kfree(buf);
+}
 
 static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size)
 {
@@ -63,40 +105,6 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size)
 	return buf;
 }
 
-static void vb2_dc_put(void *buf_priv)
-{
-	struct vb2_dc_buf *buf = buf_priv;
-
-	if (atomic_dec_and_test(&buf->refcount)) {
-		dma_free_coherent(buf->dev, buf->size, buf->vaddr,
-				  buf->dma_addr);
-		kfree(buf);
-	}
-}
-
-static void *vb2_dc_cookie(void *buf_priv)
-{
-	struct vb2_dc_buf *buf = buf_priv;
-
-	return &buf->dma_addr;
-}
-
-static void *vb2_dc_vaddr(void *buf_priv)
-{
-	struct vb2_dc_buf *buf = buf_priv;
-	if (!buf)
-		return NULL;
-
-	return buf->vaddr;
-}
-
-static unsigned int vb2_dc_num_users(void *buf_priv)
-{
-	struct vb2_dc_buf *buf = buf_priv;
-
-	return atomic_read(&buf->refcount);
-}
-
 static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
 {
 	struct vb2_dc_buf *buf = buf_priv;
@@ -110,6 +118,10 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
 				  &vb2_common_vm_ops, &buf->handler);
 }
 
+/*********************************************/
+/*       callbacks for USERPTR buffers       */
+/*********************************************/
+
 static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
 					unsigned long size, int write)
 {
@@ -148,6 +160,10 @@ static void vb2_dc_put_userptr(void *mem_priv)
 	kfree(buf);
 }
 
+/*********************************************/
+/*       DMA CONTIG exported functions       */
+/*********************************************/
+
 const struct vb2_mem_ops vb2_dma_contig_memops = {
 	.alloc		= vb2_dc_alloc,
 	.put		= vb2_dc_put,
-- 
1.7.9.5

[PATCHv10 08/26] v4l: vb2-dma-contig: add support for scatterlist in userptr mode

[Tomasz Stanislawski]

This patch introduces usage of dma_map_sg to map memory behind
a userspace pointer to a device as dma-contiguous mapping.

This patch contains some of the code kindly provided by Marek Szyprowski
<m.szyprowski@samsung.com> and Kamil Debski <k.debski@samsung.com> and Andrzej
Pietrasiewicz <andrzej.p@samsung.com>. Kind thanks for bug reports from Laurent
Pinchart <laurent.pinchart@ideasonboard.com> and Seung-Woo Kim
<sw0312.kim@samsung.com>.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/videobuf2-dma-contig.c |  226 ++++++++++++++++++++++--
 1 file changed, 210 insertions(+), 16 deletions(-)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index daac2b2..8486e06 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -11,6 +11,8 @@
  */
 
 #include <linux/module.h>
+#include <linux/scatterlist.h>
+#include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/dma-mapping.h>
 
@@ -27,6 +29,8 @@ struct vb2_dc_buf {
 	void				*vaddr;
 	unsigned long			size;
 	dma_addr_t			dma_addr;
+	enum dma_data_direction		dma_dir;
+	struct sg_table			*dma_sgt;
 
 	/* MMAP related */
 	struct vb2_vmarea_handler	handler;
@@ -37,6 +41,44 @@ struct vb2_dc_buf {
 };
 
 /*********************************************/
+/*        scatterlist table functions        */
+/*********************************************/
+
+
+static void vb2_dc_sgt_foreach_page(struct sg_table *sgt,
+	void (*cb)(struct page *pg))
+{
+	struct scatterlist *s;
+	unsigned int i;
+
+	for_each_sg(sgt->sgl, s, sgt->orig_nents, i) {
+		struct page *page = sg_page(s);
+		unsigned int n_pages = PAGE_ALIGN(s->offset + s->length)
+			>> PAGE_SHIFT;
+		unsigned int j;
+
+		for (j = 0; j < n_pages; ++j, ++page)
+			cb(page);
+	}
+}
+
+static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt)
+{
+	struct scatterlist *s;
+	dma_addr_t expected = sg_dma_address(sgt->sgl);
+	unsigned int i;
+	unsigned long size = 0;
+
+	for_each_sg(sgt->sgl, s, sgt->nents, i) {
+		if (sg_dma_address(s) != expected)
+			break;
+		expected = sg_dma_address(s) + sg_dma_len(s);
+		size += sg_dma_len(s);
+	}
+	return size;
+}
+
+/*********************************************/
 /*         callbacks for all buffers         */
 /*********************************************/
 
@@ -122,42 +164,194 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
 /*       callbacks for USERPTR buffers       */
 /*********************************************/
 
+static inline int vma_is_io(struct vm_area_struct *vma)
+{
+	return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
+}
+
+static int vb2_dc_get_user_pages(unsigned long start, struct page **pages,
+	int n_pages, struct vm_area_struct *vma, int write)
+{
+	if (vma_is_io(vma)) {
+		unsigned int i;
+
+		for (i = 0; i < n_pages; ++i, start += PAGE_SIZE) {
+			unsigned long pfn;
+			int ret = follow_pfn(vma, start, &pfn);
+
+			if (ret) {
+				pr_err("no page for address %lu\n", start);
+				return ret;
+			}
+			pages[i] = pfn_to_page(pfn);
+		}
+	} else {
+		int n;
+
+		n = get_user_pages(current, current->mm, start & PAGE_MASK,
+			n_pages, write, 1, pages, NULL);
+		/* negative error means that no page was pinned */
+		n = max(n, 0);
+		if (n != n_pages) {
+			pr_err("got only %d of %d user pages\n", n, n_pages);
+			while (n)
+				put_page(pages[--n]);
+			return -EFAULT;
+		}
+	}
+
+	return 0;
+}
+
+static void vb2_dc_put_dirty_page(struct page *page)
+{
+	set_page_dirty_lock(page);
+	put_page(page);
+}
+
+static void vb2_dc_put_userptr(void *buf_priv)
+{
+	struct vb2_dc_buf *buf = buf_priv;
+	struct sg_table *sgt = buf->dma_sgt;
+
+	dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
+	if (!vma_is_io(buf->vma))
+		vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
+
+	sg_free_table(sgt);
+	kfree(sgt);
+	vb2_put_vma(buf->vma);
+	kfree(buf);
+}
+
 static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
-					unsigned long size, int write)
+	unsigned long size, int write)
 {
+	struct vb2_dc_conf *conf = alloc_ctx;
 	struct vb2_dc_buf *buf;
+	unsigned long start;
+	unsigned long end;
+	unsigned long offset;
+	struct page **pages;
+	int n_pages;
+	int ret = 0;
 	struct vm_area_struct *vma;
-	dma_addr_t dma_addr = 0;
-	int ret;
+	struct sg_table *sgt;
+	unsigned long contig_size;
 
 	buf = kzalloc(sizeof *buf, GFP_KERNEL);
 	if (!buf)
 		return ERR_PTR(-ENOMEM);
 
-	ret = vb2_get_contig_userptr(vaddr, size, &vma, &dma_addr);
+	buf->dev = conf->dev;
+	buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
+
+	start = vaddr & PAGE_MASK;
+	offset = vaddr & ~PAGE_MASK;
+	end = PAGE_ALIGN(vaddr + size);
+	n_pages = (end - start) >> PAGE_SHIFT;
+
+	pages = kmalloc(n_pages * sizeof(pages[0]), GFP_KERNEL);
+	if (!pages) {
+		ret = -ENOMEM;
+		pr_err("failed to allocate pages table\n");
+		goto fail_buf;
+	}
+
+	/* current->mm->mmap_sem is taken by videobuf2 core */
+	vma = find_vma(current->mm, vaddr);
+	if (!vma) {
+		pr_err("no vma for address %lu\n", vaddr);
+		ret = -EFAULT;
+		goto fail_pages;
+	}
+
+	if (vma->vm_end < vaddr + size) {
+		pr_err("vma at %lu is too small for %lu bytes\n", vaddr, size);
+		ret = -EFAULT;
+		goto fail_pages;
+	}
+
+	buf->vma = vb2_get_vma(vma);
+	if (!buf->vma) {
+		pr_err("failed to copy vma\n");
+		ret = -ENOMEM;
+		goto fail_pages;
+	}
+
+	/* extract page list from userspace mapping */
+	ret = vb2_dc_get_user_pages(start, pages, n_pages, vma, write);
 	if (ret) {
-		printk(KERN_ERR "Failed acquiring VMA for vaddr 0x%08lx\n",
-				vaddr);
-		kfree(buf);
-		return ERR_PTR(ret);
+		pr_err("failed to get user pages\n");
+		goto fail_vma;
+	}
+
+	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
+	if (!sgt) {
+		pr_err("failed to allocate sg table\n");
+		ret = -ENOMEM;
+		goto fail_get_user_pages;
+	}
+
+	ret = sg_alloc_table_from_pages(sgt, pages, n_pages,
+		offset, size, GFP_KERNEL);
+	if (ret) {
+		pr_err("failed to initialize sg table\n");
+		goto fail_sgt;
+	}
+
+	/* pages are no longer needed */
+	kfree(pages);
+	pages = NULL;
+
+	sgt->nents = dma_map_sg(buf->dev, sgt->sgl, sgt->orig_nents,
+		buf->dma_dir);
+	if (sgt->nents <= 0) {
+		pr_err("failed to map scatterlist\n");
+		ret = -EIO;
+		goto fail_sgt_init;
+	}
+
+	contig_size = vb2_dc_get_contiguous_size(sgt);
+	if (contig_size < size) {
+		pr_err("contiguous mapping is too small %lu/%lu\n",
+			contig_size, size);
+		ret = -EFAULT;
+		goto fail_map_sg;
 	}
 
+	buf->dma_addr = sg_dma_address(sgt->sgl);
 	buf->size = size;
-	buf->dma_addr = dma_addr;
-	buf->vma = vma;
+	buf->dma_sgt = sgt;
 
 	return buf;
-}
 
-static void vb2_dc_put_userptr(void *mem_priv)
-{
-	struct vb2_dc_buf *buf = mem_priv;
+fail_map_sg:
+	dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
 
-	if (!buf)
-		return;
+fail_sgt_init:
+	if (!vma_is_io(buf->vma))
+		vb2_dc_sgt_foreach_page(sgt, put_page);
+	sg_free_table(sgt);
+
+fail_sgt:
+	kfree(sgt);
 
+fail_get_user_pages:
+	if (pages && !vma_is_io(buf->vma))
+		while (n_pages)
+			put_page(pages[--n_pages]);
+
+fail_vma:
 	vb2_put_vma(buf->vma);
+
+fail_pages:
+	kfree(pages); /* kfree is NULL-proof */
+
+fail_buf:
 	kfree(buf);
+
+	return ERR_PTR(ret);
 }
 
 /*********************************************/
-- 
1.7.9.5

[PATCHv10 09/26] v4l: vb2: add prepare/finish callbacks to allocators

[Tomasz Stanislawski]

From: Marek Szyprowski <m.szyprowski@samsung.com>

This patch adds support for prepare/finish callbacks in VB2 allocators. These
callback are used for buffer flushing.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/videobuf2-core.c |   11 +++++++++++
 include/media/videobuf2-core.h           |    7 +++++++
 2 files changed, 18 insertions(+)

diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index a51dad6..613dea1 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -844,6 +844,7 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
 {
 	struct vb2_queue *q = vb->vb2_queue;
 	unsigned long flags;
+	unsigned int plane;
 
 	if (vb->state != VB2_BUF_STATE_ACTIVE)
 		return;
@@ -854,6 +855,10 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
 	dprintk(4, "Done processing on buffer %d, state: %d\n",
 			vb->v4l2_buf.index, vb->state);
 
+	/* sync buffers */
+	for (plane = 0; plane < vb->num_planes; ++plane)
+		call_memop(q, finish, vb->planes[plane].mem_priv);
+
 	/* Add the buffer to the done buffers list */
 	spin_lock_irqsave(&q->done_lock, flags);
 	vb->state = state;
@@ -1136,9 +1141,15 @@ err:
 static void __enqueue_in_driver(struct vb2_buffer *vb)
 {
 	struct vb2_queue *q = vb->vb2_queue;
+	unsigned int plane;
 
 	vb->state = VB2_BUF_STATE_ACTIVE;
 	atomic_inc(&q->queued_count);
+
+	/* sync buffers */
+	for (plane = 0; plane < vb->num_planes; ++plane)
+		call_memop(q, prepare, vb->planes[plane].mem_priv);
+
 	q->ops->buf_queue(vb);
 }
 
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 689ae4a..24b9c90 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -56,6 +56,10 @@ struct vb2_fileio_data;
  *		dmabuf
  * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified
  *		  that this driver is done using the dmabuf for now
+ * @prepare:	called every time the buffer is passed from userspace to the
+ *		driver, useful for cache synchronisation, optional
+ * @finish:	called every time the buffer is passed back from the driver
+ *		to the userspace, also optional
  * @vaddr:	return a kernel virtual address to a given memory buffer
  *		associated with the passed private structure or NULL if no
  *		such mapping exists
@@ -82,6 +86,9 @@ struct vb2_mem_ops {
 					unsigned long size, int write);
 	void		(*put_userptr)(void *buf_priv);
 
+	void		(*prepare)(void *buf_priv);
+	void		(*finish)(void *buf_priv);
+
 	void		*(*attach_dmabuf)(void *alloc_ctx, struct dma_buf *dbuf,
 				unsigned long size, int write);
 	void		(*detach_dmabuf)(void *buf_priv);
-- 
1.7.9.5

[PATCHv10 10/26] v4l: vb2-dma-contig: add prepare/finish to dma-contig allocator

[Tomasz Stanislawski]

From: Marek Szyprowski <m.szyprowski@samsung.com>

Add prepare/finish callbacks to vb2-dma-contig allocator.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/videobuf2-dma-contig.c |   24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 8486e06..494a824 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -103,6 +103,28 @@ static unsigned int vb2_dc_num_users(void *buf_priv)
 	return atomic_read(&buf->refcount);
 }
 
+static void vb2_dc_prepare(void *buf_priv)
+{
+	struct vb2_dc_buf *buf = buf_priv;
+	struct sg_table *sgt = buf->dma_sgt;
+
+	if (!sgt)
+		return;
+
+	dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
+}
+
+static void vb2_dc_finish(void *buf_priv)
+{
+	struct vb2_dc_buf *buf = buf_priv;
+	struct sg_table *sgt = buf->dma_sgt;
+
+	if (!sgt)
+		return;
+
+	dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
+}
+
 /*********************************************/
 /*        callbacks for MMAP buffers         */
 /*********************************************/
@@ -366,6 +388,8 @@ const struct vb2_mem_ops vb2_dma_contig_memops = {
 	.mmap		= vb2_dc_mmap,
 	.get_userptr	= vb2_dc_get_userptr,
 	.put_userptr	= vb2_dc_put_userptr,
+	.prepare	= vb2_dc_prepare,
+	.finish		= vb2_dc_finish,
 	.num_users	= vb2_dc_num_users,
 };
 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
-- 
1.7.9.5

[PATCHv10 11/26] v4l: vb2-dma-contig: add support for dma_buf importing

[Tomasz Stanislawski]

From: Sumit Semwal <sumit.semwal@ti.com>

This patch makes changes for adding dma-contig as a dma_buf user. It provides
function implementations for the {attach, detach, map, unmap}_dmabuf()
mem_ops of DMABUF memory type.

Signed-off-by: Sumit Semwal <sumit.semwal@ti.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
	[author of the original patch]
Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
	[integration with refactored dma-contig allocator]
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/media/v4l2-core/Kconfig                |    1 +
 drivers/media/v4l2-core/videobuf2-dma-contig.c |  120 +++++++++++++++++++++++-
 2 files changed, 119 insertions(+), 2 deletions(-)

diff --git a/drivers/media/v4l2-core/Kconfig b/drivers/media/v4l2-core/Kconfig
index 2e787cc..e30583b 100644
--- a/drivers/media/v4l2-core/Kconfig
+++ b/drivers/media/v4l2-core/Kconfig
@@ -69,6 +69,7 @@ config VIDEOBUF2_DMA_CONTIG
 	tristate
 	select VIDEOBUF2_CORE
 	select VIDEOBUF2_MEMOPS
+	select DMA_SHARED_BUFFER
 
 config VIDEOBUF2_VMALLOC
 	tristate
diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 494a824..a5804cf 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -10,6 +10,7 @@
  * the Free Software Foundation.
  */
 
+#include <linux/dma-buf.h>
 #include <linux/module.h>
 #include <linux/scatterlist.h>
 #include <linux/sched.h>
@@ -38,6 +39,9 @@ struct vb2_dc_buf {
 
 	/* USERPTR related */
 	struct vm_area_struct		*vma;
+
+	/* DMABUF related */
+	struct dma_buf_attachment	*db_attach;
 };
 
 /*********************************************/
@@ -108,7 +112,8 @@ static void vb2_dc_prepare(void *buf_priv)
 	struct vb2_dc_buf *buf = buf_priv;
 	struct sg_table *sgt = buf->dma_sgt;
 
-	if (!sgt)
+	/* DMABUF exporter will flush the cache for us */
+	if (!sgt || buf->db_attach)
 		return;
 
 	dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
@@ -119,7 +124,8 @@ static void vb2_dc_finish(void *buf_priv)
 	struct vb2_dc_buf *buf = buf_priv;
 	struct sg_table *sgt = buf->dma_sgt;
 
-	if (!sgt)
+	/* DMABUF exporter will flush the cache for us */
+	if (!sgt || buf->db_attach)
 		return;
 
 	dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
@@ -377,6 +383,112 @@ fail_buf:
 }
 
 /*********************************************/
+/*       callbacks for DMABUF buffers        */
+/*********************************************/
+
+static int vb2_dc_map_dmabuf(void *mem_priv)
+{
+	struct vb2_dc_buf *buf = mem_priv;
+	struct sg_table *sgt;
+	unsigned long contig_size;
+
+	if (WARN_ON(!buf->db_attach)) {
+		pr_err("trying to pin a non attached buffer\n");
+		return -EINVAL;
+	}
+
+	if (WARN_ON(buf->dma_sgt)) {
+		pr_err("dmabuf buffer is already pinned\n");
+		return 0;
+	}
+
+	/* get the associated scatterlist for this buffer */
+	sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
+	if (IS_ERR_OR_NULL(sgt)) {
+		pr_err("Error getting dmabuf scatterlist\n");
+		return -EINVAL;
+	}
+
+	/* checking if dmabuf is big enough to store contiguous chunk */
+	contig_size = vb2_dc_get_contiguous_size(sgt);
+	if (contig_size < buf->size) {
+		pr_err("contiguous chunk is too small %lu/%lu b\n",
+			contig_size, buf->size);
+		dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
+		return -EFAULT;
+	}
+
+	buf->dma_addr = sg_dma_address(sgt->sgl);
+	buf->dma_sgt = sgt;
+
+	return 0;
+}
+
+static void vb2_dc_unmap_dmabuf(void *mem_priv)
+{
+	struct vb2_dc_buf *buf = mem_priv;
+	struct sg_table *sgt = buf->dma_sgt;
+
+	if (WARN_ON(!buf->db_attach)) {
+		pr_err("trying to unpin a not attached buffer\n");
+		return;
+	}
+
+	if (WARN_ON(!sgt)) {
+		pr_err("dmabuf buffer is already unpinned\n");
+		return;
+	}
+
+	dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
+
+	buf->dma_addr = 0;
+	buf->dma_sgt = NULL;
+}
+
+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))
+		vb2_dc_unmap_dmabuf(buf);
+
+	/* detach this attachment */
+	dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
+	kfree(buf);
+}
+
+static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
+	unsigned long size, int write)
+{
+	struct vb2_dc_conf *conf = alloc_ctx;
+	struct vb2_dc_buf *buf;
+	struct dma_buf_attachment *dba;
+
+	if (dbuf->size < size)
+		return ERR_PTR(-EFAULT);
+
+	buf = kzalloc(sizeof(*buf), GFP_KERNEL);
+	if (!buf)
+		return ERR_PTR(-ENOMEM);
+
+	buf->dev = conf->dev;
+	/* create attachment for the dmabuf with the user device */
+	dba = dma_buf_attach(dbuf, buf->dev);
+	if (IS_ERR(dba)) {
+		pr_err("failed to attach dmabuf\n");
+		kfree(buf);
+		return dba;
+	}
+
+	buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
+	buf->size = size;
+	buf->db_attach = dba;
+
+	return buf;
+}
+
+/*********************************************/
 /*       DMA CONTIG exported functions       */
 /*********************************************/
 
@@ -390,6 +502,10 @@ const struct vb2_mem_ops vb2_dma_contig_memops = {
 	.put_userptr	= vb2_dc_put_userptr,
 	.prepare	= vb2_dc_prepare,
 	.finish		= vb2_dc_finish,
+	.map_dmabuf	= vb2_dc_map_dmabuf,
+	.unmap_dmabuf	= vb2_dc_unmap_dmabuf,
+	.attach_dmabuf	= vb2_dc_attach_dmabuf,
+	.detach_dmabuf	= vb2_dc_detach_dmabuf,
 	.num_users	= vb2_dc_num_users,
 };
 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
-- 
1.7.9.5

[PATCHv10 12/26] v4l: vb2-vmalloc: add support for dmabuf importing

[Tomasz Stanislawski]

This patch adds support for importing DMABUF files for
vmalloc allocator in Videobuf2.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/Kconfig             |    1 +
 drivers/media/v4l2-core/videobuf2-vmalloc.c |   56 +++++++++++++++++++++++++++
 2 files changed, 57 insertions(+)

diff --git a/drivers/media/v4l2-core/Kconfig b/drivers/media/v4l2-core/Kconfig
index e30583b..65875c3 100644
--- a/drivers/media/v4l2-core/Kconfig
+++ b/drivers/media/v4l2-core/Kconfig
@@ -75,6 +75,7 @@ config VIDEOBUF2_VMALLOC
 	tristate
 	select VIDEOBUF2_CORE
 	select VIDEOBUF2_MEMOPS
+	select DMA_SHARED_BUFFER
 
 config VIDEOBUF2_DMA_SG
 	tristate
diff --git a/drivers/media/v4l2-core/videobuf2-vmalloc.c b/drivers/media/v4l2-core/videobuf2-vmalloc.c
index 94efa04..a47fd4f 100644
--- a/drivers/media/v4l2-core/videobuf2-vmalloc.c
+++ b/drivers/media/v4l2-core/videobuf2-vmalloc.c
@@ -30,6 +30,7 @@ struct vb2_vmalloc_buf {
 	unsigned int			n_pages;
 	atomic_t			refcount;
 	struct vb2_vmarea_handler	handler;
+	struct dma_buf			*dbuf;
 };
 
 static void vb2_vmalloc_put(void *buf_priv);
@@ -207,11 +208,66 @@ static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma)
 	return 0;
 }
 
+/*********************************************/
+/*       callbacks for DMABUF buffers        */
+/*********************************************/
+
+static int vb2_vmalloc_map_dmabuf(void *mem_priv)
+{
+	struct vb2_vmalloc_buf *buf = mem_priv;
+
+	buf->vaddr = dma_buf_vmap(buf->dbuf);
+
+	return buf->vaddr ? 0 : -EFAULT;
+}
+
+static void vb2_vmalloc_unmap_dmabuf(void *mem_priv)
+{
+	struct vb2_vmalloc_buf *buf = mem_priv;
+
+	dma_buf_vunmap(buf->dbuf, buf->vaddr);
+	buf->vaddr = NULL;
+}
+
+static void vb2_vmalloc_detach_dmabuf(void *mem_priv)
+{
+	struct vb2_vmalloc_buf *buf = mem_priv;
+
+	if (buf->vaddr)
+		dma_buf_vunmap(buf->dbuf, buf->vaddr);
+
+	kfree(buf);
+}
+
+static void *vb2_vmalloc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
+	unsigned long size, int write)
+{
+	struct vb2_vmalloc_buf *buf;
+
+	if (dbuf->size < size)
+		return ERR_PTR(-EFAULT);
+
+	buf = kzalloc(sizeof(*buf), GFP_KERNEL);
+	if (!buf)
+		return ERR_PTR(-ENOMEM);
+
+	buf->dbuf = dbuf;
+	buf->write = write;
+	buf->size = size;
+
+	return buf;
+}
+
+
 const struct vb2_mem_ops vb2_vmalloc_memops = {
 	.alloc		= vb2_vmalloc_alloc,
 	.put		= vb2_vmalloc_put,
 	.get_userptr	= vb2_vmalloc_get_userptr,
 	.put_userptr	= vb2_vmalloc_put_userptr,
+	.map_dmabuf	= vb2_vmalloc_map_dmabuf,
+	.unmap_dmabuf	= vb2_vmalloc_unmap_dmabuf,
+	.attach_dmabuf	= vb2_vmalloc_attach_dmabuf,
+	.detach_dmabuf	= vb2_vmalloc_detach_dmabuf,
 	.vaddr		= vb2_vmalloc_vaddr,
 	.mmap		= vb2_vmalloc_mmap,
 	.num_users	= vb2_vmalloc_num_users,
-- 
1.7.9.5

[PATCHv10 13/26] v4l: vivi: support for dmabuf importing

[Tomasz Stanislawski]

This patch enhances VIVI driver with a support for importing a buffer
from DMABUF file descriptors.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/platform/vivi.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/platform/vivi.c b/drivers/media/platform/vivi.c
index b366b05..9e077bb 100644
--- a/drivers/media/platform/vivi.c
+++ b/drivers/media/platform/vivi.c
@@ -1308,7 +1308,7 @@ static int __init vivi_create_instance(int inst)
 	/* initialize queue */
 	q = &dev->vb_vidq;
 	q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
-	q->io_modes = VB2_MMAP | VB2_USERPTR | VB2_READ;
+	q->io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF | VB2_READ;
 	q->drv_priv = dev;
 	q->buf_struct_size = sizeof(struct vivi_buffer);
 	q->ops = &vivi_video_qops;
-- 
1.7.9.5

[PATCHv10 14/26] v4l: s5p-tv: mixer: support for dmabuf importing

[Tomasz Stanislawski]

This patch enhances s5p-tv with support for DMABUF importing via
V4L2_MEMORY_DMABUF memory type.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/platform/s5p-tv/mixer_video.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/platform/s5p-tv/mixer_video.c b/drivers/media/platform/s5p-tv/mixer_video.c
index 0c1cd89..2421e527 100644
--- a/drivers/media/platform/s5p-tv/mixer_video.c
+++ b/drivers/media/platform/s5p-tv/mixer_video.c
@@ -1093,7 +1093,7 @@ struct mxr_layer *mxr_base_layer_create(struct mxr_device *mdev,
 
 	layer->vb_queue = (struct vb2_queue) {
 		.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE,
-		.io_modes = VB2_MMAP | VB2_USERPTR,
+		.io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF,
 		.drv_priv = layer,
 		.buf_struct_size = sizeof(struct mxr_buffer),
 		.ops = &mxr_video_qops,
-- 
1.7.9.5

[PATCHv10 15/26] v4l: s5p-fimc: support for dmabuf importing

[Tomasz Stanislawski]

This patch enhances s5p-fimc with support for DMABUF importing via
V4L2_MEMORY_DMABUF memory type.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/platform/s5p-fimc/fimc-capture.c |    2 +-
 drivers/media/platform/s5p-fimc/fimc-m2m.c     |    4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/s5p-fimc/fimc-capture.c b/drivers/media/platform/s5p-fimc/fimc-capture.c
index 367efd1..246bb32 100644
--- a/drivers/media/platform/s5p-fimc/fimc-capture.c
+++ b/drivers/media/platform/s5p-fimc/fimc-capture.c
@@ -1730,7 +1730,7 @@ static int fimc_register_capture_device(struct fimc_dev *fimc,
 	q = &fimc->vid_cap.vbq;
 	memset(q, 0, sizeof(*q));
 	q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
-	q->io_modes = VB2_MMAP | VB2_USERPTR;
+	q->io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
 	q->drv_priv = fimc->vid_cap.ctx;
 	q->ops = &fimc_capture_qops;
 	q->mem_ops = &vb2_dma_contig_memops;
diff --git a/drivers/media/platform/s5p-fimc/fimc-m2m.c b/drivers/media/platform/s5p-fimc/fimc-m2m.c
index 4500e44..17067a7 100644
--- a/drivers/media/platform/s5p-fimc/fimc-m2m.c
+++ b/drivers/media/platform/s5p-fimc/fimc-m2m.c
@@ -622,7 +622,7 @@ static int queue_init(void *priv, struct vb2_queue *src_vq,
 	int ret;
 
 	src_vq->type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
-	src_vq->io_modes = VB2_MMAP | VB2_USERPTR;
+	src_vq->io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
 	src_vq->drv_priv = ctx;
 	src_vq->ops = &fimc_qops;
 	src_vq->mem_ops = &vb2_dma_contig_memops;
@@ -633,7 +633,7 @@ static int queue_init(void *priv, struct vb2_queue *src_vq,
 		return ret;
 
 	dst_vq->type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
-	dst_vq->io_modes = VB2_MMAP | VB2_USERPTR;
+	dst_vq->io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
 	dst_vq->drv_priv = ctx;
 	dst_vq->ops = &fimc_qops;
 	dst_vq->mem_ops = &vb2_dma_contig_memops;
-- 
1.7.9.5

[PATCHv10 16/26] v4l: vb2-dma-contig: let mmap method to use dma_mmap_coherent call

[Tomasz Stanislawski]

From: Marek Szyprowski <m.szyprowski@samsung.com>

Let mmap method to use dma_mmap_coherent call.  Moreover, this patch removes
vb2_mmap_pfn_range from videobuf2 helpers as it was suggested by Laurent
Pinchart.  The function is no longer used in vb2 code.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/videobuf2-dma-contig.c |   28 +++++++++++++++--
 drivers/media/v4l2-core/videobuf2-memops.c     |   40 ------------------------
 include/media/videobuf2-memops.h               |    5 ---
 3 files changed, 26 insertions(+), 47 deletions(-)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index a5804cf..0e065ce 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -178,14 +178,38 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size)
 static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
 {
 	struct vb2_dc_buf *buf = buf_priv;
+	int ret;
 
 	if (!buf) {
 		printk(KERN_ERR "No buffer to map\n");
 		return -EINVAL;
 	}
 
-	return vb2_mmap_pfn_range(vma, buf->dma_addr, buf->size,
-				  &vb2_common_vm_ops, &buf->handler);
+	/*
+	 * dma_mmap_* uses vm_pgoff as in-buffer offset, but we want to
+	 * map whole buffer
+	 */
+	vma->vm_pgoff = 0;
+
+	ret = dma_mmap_coherent(buf->dev, vma, buf->vaddr,
+		buf->dma_addr, buf->size);
+
+	if (ret) {
+		pr_err("Remapping memory failed, error: %d\n", ret);
+		return ret;
+	}
+
+	vma->vm_flags		|= VM_DONTEXPAND | VM_RESERVED;
+	vma->vm_private_data	= &buf->handler;
+	vma->vm_ops		= &vb2_common_vm_ops;
+
+	vma->vm_ops->open(vma);
+
+	pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %ld\n",
+		__func__, (unsigned long)buf->dma_addr, vma->vm_start,
+		buf->size);
+
+	return 0;
 }
 
 /*********************************************/
diff --git a/drivers/media/v4l2-core/videobuf2-memops.c b/drivers/media/v4l2-core/videobuf2-memops.c
index 504cd4c..81c1ad8 100644
--- a/drivers/media/v4l2-core/videobuf2-memops.c
+++ b/drivers/media/v4l2-core/videobuf2-memops.c
@@ -137,46 +137,6 @@ int vb2_get_contig_userptr(unsigned long vaddr, unsigned long size,
 EXPORT_SYMBOL_GPL(vb2_get_contig_userptr);
 
 /**
- * vb2_mmap_pfn_range() - map physical pages to userspace
- * @vma:	virtual memory region for the mapping
- * @paddr:	starting physical address of the memory to be mapped
- * @size:	size of the memory to be mapped
- * @vm_ops:	vm operations to be assigned to the created area
- * @priv:	private data to be associated with the area
- *
- * Returns 0 on success.
- */
-int vb2_mmap_pfn_range(struct vm_area_struct *vma, unsigned long paddr,
-				unsigned long size,
-				const struct vm_operations_struct *vm_ops,
-				void *priv)
-{
-	int ret;
-
-	size = min_t(unsigned long, vma->vm_end - vma->vm_start, size);
-
-	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
-	ret = remap_pfn_range(vma, vma->vm_start, paddr >> PAGE_SHIFT,
-				size, vma->vm_page_prot);
-	if (ret) {
-		printk(KERN_ERR "Remapping memory failed, error: %d\n", ret);
-		return ret;
-	}
-
-	vma->vm_flags		|= VM_DONTEXPAND | VM_RESERVED;
-	vma->vm_private_data	= priv;
-	vma->vm_ops		= vm_ops;
-
-	vma->vm_ops->open(vma);
-
-	pr_debug("%s: mapped paddr 0x%08lx at 0x%08lx, size %ld\n",
-			__func__, paddr, vma->vm_start, size);
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(vb2_mmap_pfn_range);
-
-/**
  * vb2_common_vm_open() - increase refcount of the vma
  * @vma:	virtual memory region for the mapping
  *
diff --git a/include/media/videobuf2-memops.h b/include/media/videobuf2-memops.h
index 84e1f6c..f05444c 100644
--- a/include/media/videobuf2-memops.h
+++ b/include/media/videobuf2-memops.h
@@ -33,11 +33,6 @@ extern const struct vm_operations_struct vb2_common_vm_ops;
 int vb2_get_contig_userptr(unsigned long vaddr, unsigned long size,
 			   struct vm_area_struct **res_vma, dma_addr_t *res_pa);
 
-int vb2_mmap_pfn_range(struct vm_area_struct *vma, unsigned long paddr,
-				unsigned long size,
-				const struct vm_operations_struct *vm_ops,
-				void *priv);
-
 struct vm_area_struct *vb2_get_vma(struct vm_area_struct *vma);
 void vb2_put_vma(struct vm_area_struct *vma);
 
-- 
1.7.9.5

[PATCHv10 17/26] Documentation: media: description of DMABUF exporting in V4L2

[Tomasz Stanislawski]

This patch adds description and usage examples for exporting
DMABUF file descriptor in V4L2.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: linux-doc@vger.kernel.org
---
 Documentation/DocBook/media/v4l/compat.xml        |    3 +
 Documentation/DocBook/media/v4l/io.xml            |    3 +
 Documentation/DocBook/media/v4l/v4l2.xml          |    1 +
 Documentation/DocBook/media/v4l/vidioc-expbuf.xml |  212 +++++++++++++++++++++
 4 files changed, 219 insertions(+)
 create mode 100644 Documentation/DocBook/media/v4l/vidioc-expbuf.xml

diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml
index 50eb630..3dd9e78 100644
--- a/Documentation/DocBook/media/v4l/compat.xml
+++ b/Documentation/DocBook/media/v4l/compat.xml
@@ -2590,6 +2590,9 @@ ioctls.</para>
 	  <para>Importing DMABUF file descriptors as a new IO method described
 	  in <xref linkend="dmabuf" />.</para>
         </listitem>
+        <listitem>
+	  <para>Exporting DMABUF files using &VIDIOC-EXPBUF; ioctl.</para>
+        </listitem>
       </itemizedlist>
     </section>
 
diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml
index 0abb5cb..81d0ed4 100644
--- a/Documentation/DocBook/media/v4l/io.xml
+++ b/Documentation/DocBook/media/v4l/io.xml
@@ -488,6 +488,9 @@ DMA buffer from userspace using a file descriptor previously exported for a
 different or the same device (known as the importer role), or both. This
 section describes the DMABUF importer role API in V4L2.</para>
 
+    <para>Refer to <link linked="vidioc-expbuf"> DMABUF exporting </link> for
+details about exporting V4L2 buffers as DMABUF file descriptors.</para>
+
 <para>Input and output devices support the streaming I/O method when the
 <constant>V4L2_CAP_STREAMING</constant> flag in the
 <structfield>capabilities</structfield> field of &v4l2-capability; returned by
diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml
index 10ccde9..4d110b1 100644
--- a/Documentation/DocBook/media/v4l/v4l2.xml
+++ b/Documentation/DocBook/media/v4l/v4l2.xml
@@ -543,6 +543,7 @@ and discussions on the V4L mailing list.</revremark>
     &sub-enuminput;
     &sub-enumoutput;
     &sub-enumstd;
+    &sub-expbuf;
     &sub-g-audio;
     &sub-g-audioout;
     &sub-g-crop;
diff --git a/Documentation/DocBook/media/v4l/vidioc-expbuf.xml b/Documentation/DocBook/media/v4l/vidioc-expbuf.xml
new file mode 100644
index 0000000..72dfbd2
--- /dev/null
+++ b/Documentation/DocBook/media/v4l/vidioc-expbuf.xml
@@ -0,0 +1,212 @@
+<refentry id="vidioc-expbuf">
+
+  <refmeta>
+    <refentrytitle>ioctl VIDIOC_EXPBUF</refentrytitle>
+    &manvol;
+  </refmeta>
+
+  <refnamediv>
+    <refname>VIDIOC_EXPBUF</refname>
+    <refpurpose>Export a buffer as a DMABUF file descriptor.</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <funcsynopsis>
+      <funcprototype>
+	<funcdef>int <function>ioctl</function></funcdef>
+	<paramdef>int <parameter>fd</parameter></paramdef>
+	<paramdef>int <parameter>request</parameter></paramdef>
+	<paramdef>struct v4l2_exportbuffer *<parameter>argp</parameter></paramdef>
+      </funcprototype>
+    </funcsynopsis>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Arguments</title>
+
+    <variablelist>
+      <varlistentry>
+	<term><parameter>fd</parameter></term>
+	<listitem>
+	  <para>&fd;</para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><parameter>request</parameter></term>
+	<listitem>
+	  <para>VIDIOC_EXPBUF</para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><parameter>argp</parameter></term>
+	<listitem>
+	  <para></para>
+	</listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+
+  <refsect1>
+    <title>Description</title>
+
+    <note>
+      <title>Experimental</title>
+      <para>This is an <link linkend="experimental"> experimental </link>
+      interface and may change in the future.</para>
+    </note>
+
+<para>This ioctl is an extension to the <link linkend="mmap">memory
+mapping</link> I/O method, therefore it is available only for
+<constant>V4L2_MEMORY_MMAP</constant> buffers.  It can be used to export a
+buffer as a DMABUF file at any time after buffers have been allocated with the
+&VIDIOC-REQBUFS; ioctl.</para>
+
+<para> To export a buffer, applications fill &v4l2-exportbuffer;.  The
+<structfield> type </structfield> field is set to the same buffer type as was
+previously used with  &v4l2-requestbuffers;<structfield> type </structfield>.
+Applications must also set the <structfield> index </structfield> field. Valid
+index numbers range from zero to the number of buffers allocated with
+&VIDIOC-REQBUFS; (&v4l2-requestbuffers;<structfield> count </structfield>)
+minus one.  For the multi-planar API, applications set the <structfield> plane
+</structfield> field to the index of the plane to be exported. Valid planes
+range from zero to the maximal number of valid planes for the currently active
+format. For the single-planar API, applications must set <structfield> plane
+</structfield> to zero.  Additional flags may be posted in the <structfield>
+flags </structfield> field.  Refer to a manual for open() for details.
+Currently only O_CLOEXEC is supported.  All other fields must be set to zero.
+In the case of multi-planar API, every plane is exported separately using
+multiple <constant> VIDIOC_EXPBUF </constant> calls. </para>
+
+<para> After calling <constant>VIDIOC_EXPBUF</constant> the <structfield> fd
+</structfield> field will be set by a driver.  This is a DMABUF file
+descriptor. The application may pass it to other DMABUF-aware devices. Refer to
+<link linkend="dmabuf">DMABUF importing</link> for details about importing
+DMABUF files into V4L2 nodes. It is recommended to close a DMABUF file when it
+is no longer used to allow the associated memory to be reclaimed. </para>
+
+  </refsect1>
+  <refsect1>
+   <section>
+      <title>Examples</title>
+
+      <example>
+	<title>Exporting a buffer.</title>
+	<programlisting>
+int buffer_export(int v4lfd, &v4l2-buf-type; bt, int index, int *dmafd)
+{
+	&v4l2-exportbuffer; expbuf;
+
+	memset(&amp;expbuf, 0, sizeof(expbuf));
+	expbuf.type = bt;
+	expbuf.index = index;
+	if (ioctl(v4lfd, &VIDIOC-EXPBUF;, &amp;expbuf) == -1) {
+		perror("VIDIOC_EXPBUF");
+		return -1;
+	}
+
+	*dmafd = expbuf.fd;
+
+	return 0;
+}
+        </programlisting>
+      </example>
+
+      <example>
+	<title>Exporting a buffer using the multi-planar API.</title>
+	<programlisting>
+int buffer_export_mp(int v4lfd, &v4l2-buf-type; bt, int index,
+	int dmafd[], int n_planes)
+{
+	int i;
+
+	for (i = 0; i &lt; n_planes; ++i) {
+		&v4l2-exportbuffer; expbuf;
+
+		memset(&amp;expbuf, 0, sizeof(expbuf));
+		expbuf.type = bt;
+		expbuf.index = index;
+		expbuf.plane = i;
+		if (ioctl(v4lfd, &VIDIOC-EXPBUF;, &amp;expbuf) == -1) {
+			perror("VIDIOC_EXPBUF");
+			while (i)
+				close(dmafd[--i]);
+			return -1;
+		}
+		dmafd[i] = expbuf.fd;
+	}
+
+	return 0;
+}
+        </programlisting>
+      </example>
+   </section>
+  </refsect1>
+
+  <refsect1>
+    <table pgwide="1" frame="none" id="v4l2-exportbuffer">
+      <title>struct <structname>v4l2_exportbuffer</structname></title>
+      <tgroup cols="3">
+	&cs-str;
+	<tbody valign="top">
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>type</structfield></entry>
+	    <entry>Type of the buffer, same as &v4l2-format;
+<structfield>type</structfield> or &v4l2-requestbuffers;
+<structfield>type</structfield>, set by the application. See <xref
+linkend="v4l2-buf-type" /></entry>
+	  </row>
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>index</structfield></entry>
+	    <entry>Number of the buffer, set by the application. This field is
+only used for <link linkend="mmap">memory mapping</link> I/O and can range from
+zero to the number of buffers allocated with the &VIDIOC-REQBUFS; and/or
+&VIDIOC-CREATE-BUFS; ioctls. </entry>
+	  </row>
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>plane</structfield></entry>
+	    <entry>Index of the plane to be exported when using the
+multi-planar API. Otherwise this value must be set to zero. </entry>
+	  </row>
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>flags</structfield></entry>
+	    <entry>Flags for the newly created file, currently only <constant>
+O_CLOEXEC </constant> is supported, refer to the manual of open() for more
+details.</entry>
+	  </row>
+	  <row>
+	    <entry>__s32</entry>
+	    <entry><structfield>fd</structfield></entry>
+	    <entry>The DMABUF file descriptor associated with a buffer. Set by
+		the driver.</entry>
+	  </row>
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>reserved[11]</structfield></entry>
+	    <entry>Reserved field for future use. Must be set to zero.</entry>
+	  </row>
+	</tbody>
+      </tgroup>
+    </table>
+
+  </refsect1>
+
+  <refsect1>
+    &return-value;
+    <variablelist>
+      <varlistentry>
+	<term><errorcode>EINVAL</errorcode></term>
+	<listitem>
+	  <para>A queue is not in MMAP mode or DMABUF exporting is not
+supported or <structfield> flags </structfield> or <structfield> type
+</structfield> or <structfield> index </structfield> or <structfield> plane
+</structfield> fields are invalid.</para>
+	</listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+
+</refentry>
-- 
1.7.9.5

[PATCHv10 18/26] v4l: add buffer exporting via dmabuf

[Tomasz Stanislawski]

This patch adds extension to V4L2 api. It allow to export a mmap buffer as file
descriptor. New ioctl VIDIOC_EXPBUF is added. It takes a buffer offset used by
mmap and return a file descriptor on success.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c |    1 +
 drivers/media/v4l2-core/v4l2-dev.c            |    1 +
 drivers/media/v4l2-core/v4l2-ioctl.c          |   10 +++++++++
 include/linux/videodev2.h                     |   28 +++++++++++++++++++++++++
 include/media/v4l2-ioctl.h                    |    2 ++
 5 files changed, 42 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index cc5998b..7157af3 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -1018,6 +1018,7 @@ long v4l2_compat_ioctl32(struct file *file, unsigned int cmd, unsigned long arg)
 	case VIDIOC_S_FBUF32:
 	case VIDIOC_OVERLAY32:
 	case VIDIOC_QBUF32:
+	case VIDIOC_EXPBUF:
 	case VIDIOC_DQBUF32:
 	case VIDIOC_STREAMON32:
 	case VIDIOC_STREAMOFF32:
diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index a2df842..98dcad9 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -571,6 +571,7 @@ static void determine_valid_ioctls(struct video_device *vdev)
 	SET_VALID_IOCTL(ops, VIDIOC_REQBUFS, vidioc_reqbufs);
 	SET_VALID_IOCTL(ops, VIDIOC_QUERYBUF, vidioc_querybuf);
 	SET_VALID_IOCTL(ops, VIDIOC_QBUF, vidioc_qbuf);
+	SET_VALID_IOCTL(ops, VIDIOC_EXPBUF, vidioc_expbuf);
 	SET_VALID_IOCTL(ops, VIDIOC_DQBUF, vidioc_dqbuf);
 	SET_VALID_IOCTL(ops, VIDIOC_STREAMON, vidioc_streamon);
 	SET_VALID_IOCTL(ops, VIDIOC_STREAMOFF, vidioc_streamoff);
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 530a67e..aa6e7c7 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -454,6 +454,15 @@ static void v4l_print_buffer(const void *arg, bool write_only)
 			tc->type, tc->flags, tc->frames, *(__u32 *)tc->userbits);
 }
 
+static void v4l_print_exportbuffer(const void *arg, bool write_only)
+{
+	const struct v4l2_exportbuffer *p = arg;
+
+	pr_cont("fd=%d, type=%s, index=%u, plane=%u, flags=0x%08x\n",
+		p->fd, prt_names(p->type, v4l2_type_names),
+		p->index, p->plane, p->flags);
+}
+
 static void v4l_print_create_buffers(const void *arg, bool write_only)
 {
 	const struct v4l2_create_buffers *p = arg;
@@ -1961,6 +1970,7 @@ static struct v4l2_ioctl_info v4l2_ioctls[] = {
 	IOCTL_INFO_STD(VIDIOC_S_FBUF, vidioc_s_fbuf, v4l_print_framebuffer, INFO_FL_PRIO),
 	IOCTL_INFO_FNC(VIDIOC_OVERLAY, v4l_overlay, v4l_print_u32, INFO_FL_PRIO),
 	IOCTL_INFO_FNC(VIDIOC_QBUF, v4l_qbuf, v4l_print_buffer, INFO_FL_QUEUE),
+	IOCTL_INFO_STD(VIDIOC_EXPBUF, vidioc_expbuf, v4l_print_exportbuffer, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_exportbuffer, flags)),
 	IOCTL_INFO_FNC(VIDIOC_DQBUF, v4l_dqbuf, v4l_print_buffer, INFO_FL_QUEUE),
 	IOCTL_INFO_FNC(VIDIOC_STREAMON, v4l_streamon, v4l_print_buftype, INFO_FL_PRIO | INFO_FL_QUEUE),
 	IOCTL_INFO_FNC(VIDIOC_STREAMOFF, v4l_streamoff, v4l_print_buftype, INFO_FL_PRIO | INFO_FL_QUEUE),
diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index 07bc5d6..19765df 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -696,6 +696,33 @@ struct v4l2_buffer {
 #define V4L2_BUF_FLAG_NO_CACHE_INVALIDATE	0x0800
 #define V4L2_BUF_FLAG_NO_CACHE_CLEAN		0x1000
 
+/**
+ * struct v4l2_exportbuffer - export of video buffer as DMABUF file descriptor
+ *
+ * @index:	id number of the buffer
+ * @type:	enum v4l2_buf_type; buffer type (type == *_MPLANE for
+ *		multiplanar buffers);
+ * @plane:	index of the plane to be exported, 0 for single plane queues
+ * @flags:	flags for newly created file, currently only O_CLOEXEC is
+ *		supported, refer to manual of open syscall for more details
+ * @fd:		file descriptor associated with DMABUF (set by driver)
+ *
+ * Contains data used for exporting a video buffer as DMABUF file descriptor.
+ * The buffer is identified by a 'cookie' returned by VIDIOC_QUERYBUF
+ * (identical to the cookie used to mmap() the buffer to userspace). All
+ * reserved fields must be set to zero. The field reserved0 is expected to
+ * become a structure 'type' allowing an alternative layout of the structure
+ * content. Therefore this field should not be used for any other extensions.
+ */
+struct v4l2_exportbuffer {
+	__u32		type; /* enum v4l2_buf_type */
+	__u32		index;
+	__u32		plane;
+	__u32		flags;
+	__s32		fd;
+	__u32		reserved[11];
+};
+
 /*
  *	O V E R L A Y   P R E V I E W
  */
@@ -1897,6 +1924,7 @@ struct v4l2_create_buffers {
 #define VIDIOC_S_FBUF		 _IOW('V', 11, struct v4l2_framebuffer)
 #define VIDIOC_OVERLAY		 _IOW('V', 14, int)
 #define VIDIOC_QBUF		_IOWR('V', 15, struct v4l2_buffer)
+#define VIDIOC_EXPBUF		_IOWR('V', 16, struct v4l2_exportbuffer)
 #define VIDIOC_DQBUF		_IOWR('V', 17, struct v4l2_buffer)
 #define VIDIOC_STREAMON		 _IOW('V', 18, int)
 #define VIDIOC_STREAMOFF	 _IOW('V', 19, int)
diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
index e48b571..4118ad1 100644
--- a/include/media/v4l2-ioctl.h
+++ b/include/media/v4l2-ioctl.h
@@ -111,6 +111,8 @@ struct v4l2_ioctl_ops {
 	int (*vidioc_reqbufs) (struct file *file, void *fh, struct v4l2_requestbuffers *b);
 	int (*vidioc_querybuf)(struct file *file, void *fh, struct v4l2_buffer *b);
 	int (*vidioc_qbuf)    (struct file *file, void *fh, struct v4l2_buffer *b);
+	int (*vidioc_expbuf)  (struct file *file, void *fh,
+				struct v4l2_exportbuffer *e);
 	int (*vidioc_dqbuf)   (struct file *file, void *fh, struct v4l2_buffer *b);
 
 	int (*vidioc_create_bufs)(struct file *file, void *fh, struct v4l2_create_buffers *b);
-- 
1.7.9.5

[PATCHv10 19/26] v4l: vb2: add buffer exporting via dmabuf

[Tomasz Stanislawski]

This patch adds extension to videobuf2-core. It allow to export a mmap buffer
as a file descriptor.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/v4l2-mem2mem.c   |   13 +++++
 drivers/media/v4l2-core/videobuf2-core.c |   83 ++++++++++++++++++++++++++++++
 include/media/v4l2-mem2mem.h             |    3 ++
 include/media/videobuf2-core.h           |    4 ++
 4 files changed, 103 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-mem2mem.c b/drivers/media/v4l2-core/v4l2-mem2mem.c
index 3ac8358..9aa7cc7 100644
--- a/drivers/media/v4l2-core/v4l2-mem2mem.c
+++ b/drivers/media/v4l2-core/v4l2-mem2mem.c
@@ -369,6 +369,19 @@ int v4l2_m2m_dqbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 EXPORT_SYMBOL_GPL(v4l2_m2m_dqbuf);
 
 /**
+ * v4l2_m2m_expbuf() - export a source or destination buffer, depending on
+ * the type
+ */
+int v4l2_m2m_expbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
+		  struct v4l2_exportbuffer *eb)
+{
+	struct vb2_queue *vq;
+
+	vq = v4l2_m2m_get_vq(m2m_ctx, eb->type);
+	return vb2_expbuf(vq, eb);
+}
+EXPORT_SYMBOL_GPL(v4l2_m2m_expbuf);
+/**
  * v4l2_m2m_streamon() - turn on streaming for a video queue
  */
 int v4l2_m2m_streamon(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 613dea1..9f81be2 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -1751,6 +1751,79 @@ static int __find_plane_by_offset(struct vb2_queue *q, unsigned long off,
 }
 
 /**
+ * vb2_expbuf() - Export a buffer as a file descriptor
+ * @q:		videobuf2 queue
+ * @eb:		export buffer structure passed from userspace to vidioc_expbuf
+ *		handler in driver
+ *
+ * The return values from this function are intended to be directly returned
+ * from vidioc_expbuf handler in driver.
+ */
+int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb)
+{
+	struct vb2_buffer *vb = NULL;
+	struct vb2_plane *vb_plane;
+	int ret;
+	struct dma_buf *dbuf;
+
+	if (q->memory != V4L2_MEMORY_MMAP) {
+		dprintk(1, "Queue is not currently set up for mmap\n");
+		return -EINVAL;
+	}
+
+	if (!q->mem_ops->get_dmabuf) {
+		dprintk(1, "Queue does not support DMA buffer exporting\n");
+		return -EINVAL;
+	}
+
+	if (eb->flags & ~O_CLOEXEC) {
+		dprintk(1, "Queue does support only O_CLOEXEC flag\n");
+		return -EINVAL;
+	}
+
+	if (eb->type != q->type) {
+		dprintk(1, "qbuf: invalid buffer type\n");
+		return -EINVAL;
+	}
+
+	if (eb->index >= q->num_buffers) {
+		dprintk(1, "buffer index out of range\n");
+		return -EINVAL;
+	}
+
+	vb = q->bufs[eb->index];
+
+	if (eb->plane >= vb->num_planes) {
+		dprintk(1, "buffer plane out of range\n");
+		return -EINVAL;
+	}
+
+	vb_plane = &vb->planes[eb->plane];
+
+	dbuf = call_memop(q, get_dmabuf, vb_plane->mem_priv);
+	if (IS_ERR_OR_NULL(dbuf)) {
+		dprintk(1, "Failed to export buffer %d, plane %d\n",
+			eb->index, eb->plane);
+		return -EINVAL;
+	}
+
+	ret = dma_buf_fd(dbuf, eb->flags);
+	if (ret < 0) {
+		dprintk(3, "buffer %d, plane %d failed to export (%d)\n",
+			eb->index, eb->plane, ret);
+		dma_buf_put(dbuf);
+		return ret;
+	}
+
+	dprintk(3, "buffer %d, plane %d exported as %d descriptor\n",
+		eb->index, eb->plane, ret);
+	eb->fd = ret;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vb2_expbuf);
+
+/**
  * vb2_mmap() - map video buffers into application address space
  * @q:		videobuf2 queue
  * @vma:	vma passed to the mmap file operation handler in the driver
@@ -2456,6 +2529,16 @@ int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i)
 }
 EXPORT_SYMBOL_GPL(vb2_ioctl_streamoff);
 
+int vb2_ioctl_expbuf(struct file *file, void *priv, struct v4l2_exportbuffer *p)
+{
+	struct video_device *vdev = video_devdata(file);
+
+	if (vb2_queue_is_busy(vdev, file))
+		return -EBUSY;
+	return vb2_expbuf(vdev->queue, p);
+}
+EXPORT_SYMBOL_GPL(vb2_ioctl_expbuf);
+
 /* v4l2_file_operations helpers */
 
 int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma)
diff --git a/include/media/v4l2-mem2mem.h b/include/media/v4l2-mem2mem.h
index 131cc4a..7e82d2b 100644
--- a/include/media/v4l2-mem2mem.h
+++ b/include/media/v4l2-mem2mem.h
@@ -111,6 +111,9 @@ int v4l2_m2m_qbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 int v4l2_m2m_dqbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 		   struct v4l2_buffer *buf);
 
+int v4l2_m2m_expbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
+		   struct v4l2_exportbuffer *eb);
+
 int v4l2_m2m_streamon(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 		      enum v4l2_buf_type type);
 int v4l2_m2m_streamoff(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 24b9c90..9cfd4ee 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -81,6 +81,7 @@ struct vb2_fileio_data;
 struct vb2_mem_ops {
 	void		*(*alloc)(void *alloc_ctx, unsigned long size);
 	void		(*put)(void *buf_priv);
+	struct dma_buf *(*get_dmabuf)(void *buf_priv);
 
 	void		*(*get_userptr)(void *alloc_ctx, unsigned long vaddr,
 					unsigned long size, int write);
@@ -363,6 +364,7 @@ int __must_check vb2_queue_init(struct vb2_queue *q);
 void vb2_queue_release(struct vb2_queue *q);
 
 int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b);
+int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb);
 int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking);
 
 int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
@@ -472,6 +474,8 @@ int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p);
 int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p);
 int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i);
 int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i);
+int vb2_ioctl_expbuf(struct file *file, void *priv,
+	struct v4l2_exportbuffer *p);
 
 /* struct v4l2_file_operations helpers */
 
-- 
1.7.9.5

[PATCHv10 20/26] v4l: vb2-dma-contig: add support for DMABUF exporting

[Tomasz Stanislawski]

This patch adds support for exporting a dma-contig buffer using
DMABUF interface.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/videobuf2-dma-contig.c |  200 ++++++++++++++++++++++++
 1 file changed, 200 insertions(+)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 0e065ce..b138b5c 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -36,6 +36,7 @@ struct vb2_dc_buf {
 	/* MMAP related */
 	struct vb2_vmarea_handler	handler;
 	atomic_t			refcount;
+	struct sg_table			*sgt_base;
 
 	/* USERPTR related */
 	struct vm_area_struct		*vma;
@@ -142,6 +143,10 @@ static void vb2_dc_put(void *buf_priv)
 	if (!atomic_dec_and_test(&buf->refcount))
 		return;
 
+	if (buf->sgt_base) {
+		sg_free_table(buf->sgt_base);
+		kfree(buf->sgt_base);
+	}
 	dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
 	kfree(buf);
 }
@@ -213,6 +218,200 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
 }
 
 /*********************************************/
+/*         DMABUF ops for exporters          */
+/*********************************************/
+
+struct vb2_dc_attachment {
+	struct sg_table sgt;
+	enum dma_data_direction dir;
+};
+
+static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
+	struct dma_buf_attachment *dbuf_attach)
+{
+	struct vb2_dc_attachment *attach;
+	unsigned int i;
+	struct scatterlist *rd, *wr;
+	struct sg_table *sgt;
+	struct vb2_dc_buf *buf = dbuf->priv;
+	int ret;
+
+	attach = kzalloc(sizeof(*attach), GFP_KERNEL);
+	if (!attach)
+		return -ENOMEM;
+
+	sgt = &attach->sgt;
+	/* Copy the buf->base_sgt scatter list to the attachment, as we can't
+	 * map the same scatter list to multiple attachments at the same time.
+	 */
+	ret = sg_alloc_table(sgt, buf->sgt_base->orig_nents, GFP_KERNEL);
+	if (ret) {
+		kfree(attach);
+		return -ENOMEM;
+	}
+
+	rd = buf->sgt_base->sgl;
+	wr = sgt->sgl;
+	for (i = 0; i < sgt->orig_nents; ++i) {
+		sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
+		rd = sg_next(rd);
+		wr = sg_next(wr);
+	}
+
+	attach->dir = DMA_NONE;
+	dbuf_attach->priv = attach;
+
+	return 0;
+}
+
+static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
+	struct dma_buf_attachment *db_attach)
+{
+	struct vb2_dc_attachment *attach = db_attach->priv;
+	struct sg_table *sgt;
+
+	if (!attach)
+		return;
+
+	sgt = &attach->sgt;
+
+	/* release the scatterlist cache */
+	if (attach->dir != DMA_NONE)
+		dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
+			attach->dir);
+	sg_free_table(sgt);
+	kfree(attach);
+	db_attach->priv = NULL;
+}
+
+static struct sg_table *vb2_dc_dmabuf_ops_map(
+	struct dma_buf_attachment *db_attach, enum dma_data_direction dir)
+{
+	struct vb2_dc_attachment *attach = db_attach->priv;
+	/* stealing dmabuf mutex to serialize map/unmap operations */
+	struct mutex *lock = &db_attach->dmabuf->lock;
+	struct sg_table *sgt;
+	int ret;
+
+	mutex_lock(lock);
+
+	sgt = &attach->sgt;
+	/* return previously mapped sg table */
+	if (attach->dir == dir) {
+		mutex_unlock(lock);
+		return sgt;
+	}
+
+	/* release any previous cache */
+	if (attach->dir != DMA_NONE) {
+		dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
+			attach->dir);
+		attach->dir = DMA_NONE;
+	}
+
+	/* mapping to the client with new direction */
+	ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dir);
+	if (ret <= 0) {
+		pr_err("failed to map scatterlist\n");
+		mutex_unlock(lock);
+		return ERR_PTR(-EIO);
+	}
+
+	attach->dir = dir;
+
+	mutex_unlock(lock);
+
+	return sgt;
+}
+
+static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
+	struct sg_table *sgt, enum dma_data_direction dir)
+{
+	/* nothing to be done here */
+}
+
+static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf)
+{
+	/* drop reference obtained in vb2_dc_get_dmabuf */
+	vb2_dc_put(dbuf->priv);
+}
+
+static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
+{
+	struct vb2_dc_buf *buf = dbuf->priv;
+
+	return buf->vaddr + pgnum * PAGE_SIZE;
+}
+
+static void *vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf)
+{
+	struct vb2_dc_buf *buf = dbuf->priv;
+
+	return buf->vaddr;
+}
+
+static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf,
+	struct vm_area_struct *vma)
+{
+	return vb2_dc_mmap(dbuf->priv, vma);
+}
+
+static struct dma_buf_ops vb2_dc_dmabuf_ops = {
+	.attach = vb2_dc_dmabuf_ops_attach,
+	.detach = vb2_dc_dmabuf_ops_detach,
+	.map_dma_buf = vb2_dc_dmabuf_ops_map,
+	.unmap_dma_buf = vb2_dc_dmabuf_ops_unmap,
+	.kmap = vb2_dc_dmabuf_ops_kmap,
+	.kmap_atomic = vb2_dc_dmabuf_ops_kmap,
+	.vmap = vb2_dc_dmabuf_ops_vmap,
+	.mmap = vb2_dc_dmabuf_ops_mmap,
+	.release = vb2_dc_dmabuf_ops_release,
+};
+
+static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
+{
+	int ret;
+	struct sg_table *sgt;
+
+	sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
+	if (!sgt) {
+		dev_err(buf->dev, "failed to alloc sg table\n");
+		return NULL;
+	}
+
+	ret = dma_get_sgtable(buf->dev, sgt, buf->vaddr, buf->dma_addr,
+		buf->size);
+	if (ret < 0) {
+		dev_err(buf->dev, "failed to get scatterlist from DMA API\n");
+		kfree(sgt);
+		return NULL;
+	}
+
+	return sgt;
+}
+
+static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv)
+{
+	struct vb2_dc_buf *buf = buf_priv;
+	struct dma_buf *dbuf;
+
+	if (!buf->sgt_base)
+		buf->sgt_base = vb2_dc_get_base_sgt(buf);
+
+	if (WARN_ON(!buf->sgt_base))
+		return NULL;
+
+	dbuf = dma_buf_export(buf, &vb2_dc_dmabuf_ops, buf->size, 0);
+	if (IS_ERR(dbuf))
+		return NULL;
+
+	/* dmabuf keeps reference to vb2 buffer */
+	atomic_inc(&buf->refcount);
+
+	return dbuf;
+}
+
+/*********************************************/
 /*       callbacks for USERPTR buffers       */
 /*********************************************/
 
@@ -519,6 +718,7 @@ static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
 const struct vb2_mem_ops vb2_dma_contig_memops = {
 	.alloc		= vb2_dc_alloc,
 	.put		= vb2_dc_put,
+	.get_dmabuf	= vb2_dc_get_dmabuf,
 	.cookie		= vb2_dc_cookie,
 	.vaddr		= vb2_dc_vaddr,
 	.mmap		= vb2_dc_mmap,
-- 
1.7.9.5

[PATCHv10 21/26] v4l: vb2-dma-contig: add reference counting for a device from allocator context

[Tomasz Stanislawski]

This patch adds taking reference to the device for MMAP buffers.

Such buffers, may be exported using DMABUF mechanism. If the driver that
created a queue is unloaded then the queue is released, the device might be
released too.  However, buffers cannot be released if they are referenced by
DMABUF descriptor(s). The device pointer kept in a buffer must be valid for the
whole buffer's lifetime. Therefore MMAP buffers should take a reference to the
device to avoid risk of dangling pointers.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/videobuf2-dma-contig.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index b138b5c..2d661fd 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -148,6 +148,7 @@ static void vb2_dc_put(void *buf_priv)
 		kfree(buf->sgt_base);
 	}
 	dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
+	put_device(buf->dev);
 	kfree(buf);
 }
 
@@ -168,6 +169,9 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size)
 		return ERR_PTR(-ENOMEM);
 	}
 
+	/* prevent the device from release while the buffer is exported */
+	get_device(dev);
+
 	buf->dev = dev;
 	buf->size = size;
 
-- 
1.7.9.5

[PATCHv10 22/26] v4l: vb2-dma-contig: fail if user ptr buffer is not correctly aligned

[Tomasz Stanislawski]

From: Marek Szyprowski <m.szyprowski@samsung.com>

The DMA transfer must be aligned to a specific value. If userptr is not aligned
to DMA requirements then unexpected corruptions of the memory may occur before
or after a buffer.  To prevent such situations, all unligned userptr buffers
are rejected at VIDIOC_QBUF.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/videobuf2-dma-contig.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 2d661fd..571a919 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -493,6 +493,18 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
 	struct vm_area_struct *vma;
 	struct sg_table *sgt;
 	unsigned long contig_size;
+	unsigned long dma_align = dma_get_cache_alignment();
+
+	/* Only cache aligned DMA transfers are reliable */
+	if (!IS_ALIGNED(vaddr | size, dma_align)) {
+		pr_debug("user data must be aligned to %lu bytes\n", dma_align);
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (!size) {
+		pr_debug("size is zero\n");
+		return ERR_PTR(-EINVAL);
+	}
 
 	buf = kzalloc(sizeof *buf, GFP_KERNEL);
 	if (!buf)
-- 
1.7.9.5

[PATCHv10 23/26] v4l: vb2-dma-contig: align buffer size to PAGE_SIZE

[Tomasz Stanislawski]

Most operations on DMA and DMABUF framework need page
aligned buffers. This fix guarantees this requirement
for vb2-dma-contig buffers.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
---
 drivers/media/v4l2-core/videobuf2-dma-contig.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 571a919..002ee50 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -162,6 +162,9 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size)
 	if (!buf)
 		return ERR_PTR(-ENOMEM);
 
+	/* align image size to PAGE_SIZE */
+	size = PAGE_ALIGN(size);
+
 	buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr, GFP_KERNEL);
 	if (!buf->vaddr) {
 		dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
-- 
1.7.9.5

[PATCHv10 24/26] v4l: s5p-fimc: support for dmabuf exporting

[Tomasz Stanislawski]

This patch enhances s5p-fimc with support for DMABUF exporting via
VIDIOC_EXPBUF ioctl.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: Sylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/platform/s5p-fimc/fimc-capture.c |    9 +++++++++
 drivers/media/platform/s5p-fimc/fimc-m2m.c     |   10 ++++++++++
 2 files changed, 19 insertions(+)

diff --git a/drivers/media/platform/s5p-fimc/fimc-capture.c b/drivers/media/platform/s5p-fimc/fimc-capture.c
index 246bb32..e5fd159 100644
--- a/drivers/media/platform/s5p-fimc/fimc-capture.c
+++ b/drivers/media/platform/s5p-fimc/fimc-capture.c
@@ -1231,6 +1231,14 @@ static int fimc_cap_qbuf(struct file *file, void *priv,
 	return vb2_qbuf(&fimc->vid_cap.vbq, buf);
 }
 
+static int fimc_cap_expbuf(struct file *file, void *priv,
+			  struct v4l2_exportbuffer *eb)
+{
+	struct fimc_dev *fimc = video_drvdata(file);
+
+	return vb2_expbuf(&fimc->vid_cap.vbq, eb);
+}
+
 static int fimc_cap_dqbuf(struct file *file, void *priv,
 			   struct v4l2_buffer *buf)
 {
@@ -1355,6 +1363,7 @@ static const struct v4l2_ioctl_ops fimc_capture_ioctl_ops = {
 
 	.vidioc_qbuf			= fimc_cap_qbuf,
 	.vidioc_dqbuf			= fimc_cap_dqbuf,
+	.vidioc_expbuf			= fimc_cap_expbuf,
 
 	.vidioc_prepare_buf		= fimc_cap_prepare_buf,
 	.vidioc_create_bufs		= fimc_cap_create_bufs,
diff --git a/drivers/media/platform/s5p-fimc/fimc-m2m.c b/drivers/media/platform/s5p-fimc/fimc-m2m.c
index 17067a7..1cd4fcf 100644
--- a/drivers/media/platform/s5p-fimc/fimc-m2m.c
+++ b/drivers/media/platform/s5p-fimc/fimc-m2m.c
@@ -439,6 +439,15 @@ static int fimc_m2m_dqbuf(struct file *file, void *fh,
 	return v4l2_m2m_dqbuf(file, ctx->m2m_ctx, buf);
 }
 
+static int fimc_m2m_expbuf(struct file *file, void *fh,
+			    struct v4l2_exportbuffer *eb)
+{
+	struct fimc_ctx *ctx = fh_to_ctx(fh);
+
+	return v4l2_m2m_expbuf(file, ctx->m2m_ctx, eb);
+}
+
+
 static int fimc_m2m_streamon(struct file *file, void *fh,
 			     enum v4l2_buf_type type)
 {
@@ -607,6 +616,7 @@ static const struct v4l2_ioctl_ops fimc_m2m_ioctl_ops = {
 	.vidioc_querybuf		= fimc_m2m_querybuf,
 	.vidioc_qbuf			= fimc_m2m_qbuf,
 	.vidioc_dqbuf			= fimc_m2m_dqbuf,
+	.vidioc_expbuf			= fimc_m2m_expbuf,
 	.vidioc_streamon		= fimc_m2m_streamon,
 	.vidioc_streamoff		= fimc_m2m_streamoff,
 	.vidioc_g_crop			= fimc_m2m_g_crop,
-- 
1.7.9.5

[PATCHv10 25/26] v4l: s5p-tv: mixer: support for dmabuf exporting

[Tomasz Stanislawski]

This patch enhances s5p-tv with support for DMABUF exporting via
VIDIOC_EXPBUF ioctl.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/platform/s5p-tv/mixer_video.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/media/platform/s5p-tv/mixer_video.c b/drivers/media/platform/s5p-tv/mixer_video.c
index 2421e527..5e3cdb2 100644
--- a/drivers/media/platform/s5p-tv/mixer_video.c
+++ b/drivers/media/platform/s5p-tv/mixer_video.c
@@ -698,6 +698,15 @@ static int mxr_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p)
 	return vb2_dqbuf(&layer->vb_queue, p, file->f_flags & O_NONBLOCK);
 }
 
+static int mxr_expbuf(struct file *file, void *priv,
+	struct v4l2_exportbuffer *eb)
+{
+	struct mxr_layer *layer = video_drvdata(file);
+
+	mxr_dbg(layer->mdev, "%s:%d\n", __func__, __LINE__);
+	return vb2_expbuf(&layer->vb_queue, eb);
+}
+
 static int mxr_streamon(struct file *file, void *priv, enum v4l2_buf_type i)
 {
 	struct mxr_layer *layer = video_drvdata(file);
@@ -725,6 +734,7 @@ static const struct v4l2_ioctl_ops mxr_ioctl_ops = {
 	.vidioc_querybuf = mxr_querybuf,
 	.vidioc_qbuf = mxr_qbuf,
 	.vidioc_dqbuf = mxr_dqbuf,
+	.vidioc_expbuf = mxr_expbuf,
 	/* Streaming control */
 	.vidioc_streamon = mxr_streamon,
 	.vidioc_streamoff = mxr_streamoff,
-- 
1.7.9.5

[PATCHv10 26/26] v4l: s5p-mfc: support for dmabuf exporting

[Tomasz Stanislawski]

This patch enhances s5p-mfc with support for DMABUF exporting via
VIDIOC_EXPBUF ioctl.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: Kamil Debski <k.debski@samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/platform/s5p-mfc/s5p_mfc_dec.c |   14 ++++++++++++++
 drivers/media/platform/s5p-mfc/s5p_mfc_enc.c |   14 ++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c b/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c
index eb6a70b..6dad9a7 100644
--- a/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c
+++ b/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c
@@ -636,6 +636,19 @@ static int vidioc_dqbuf(struct file *file, void *priv, struct v4l2_buffer *buf)
 	return -EINVAL;
 }
 
+/* Export DMA buffer */
+static int vidioc_expbuf(struct file *file, void *priv,
+	struct v4l2_exportbuffer *eb)
+{
+	struct s5p_mfc_ctx *ctx = fh_to_ctx(priv);
+
+	if (eb->type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE)
+		return vb2_expbuf(&ctx->vq_src, eb);
+	if (eb->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE)
+		return vb2_expbuf(&ctx->vq_dst, eb);
+	return -EINVAL;
+}
+
 /* Stream on */
 static int vidioc_streamon(struct file *file, void *priv,
 			   enum v4l2_buf_type type)
@@ -813,6 +826,7 @@ static const struct v4l2_ioctl_ops s5p_mfc_dec_ioctl_ops = {
 	.vidioc_querybuf = vidioc_querybuf,
 	.vidioc_qbuf = vidioc_qbuf,
 	.vidioc_dqbuf = vidioc_dqbuf,
+	.vidioc_expbuf = vidioc_expbuf,
 	.vidioc_streamon = vidioc_streamon,
 	.vidioc_streamoff = vidioc_streamoff,
 	.vidioc_g_crop = vidioc_g_crop,
diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc_enc.c b/drivers/media/platform/s5p-mfc/s5p_mfc_enc.c
index 2af6d52..22bf684 100644
--- a/drivers/media/platform/s5p-mfc/s5p_mfc_enc.c
+++ b/drivers/media/platform/s5p-mfc/s5p_mfc_enc.c
@@ -1165,6 +1165,19 @@ static int vidioc_dqbuf(struct file *file, void *priv, struct v4l2_buffer *buf)
 	return ret;
 }
 
+/* Export DMA buffer */
+static int vidioc_expbuf(struct file *file, void *priv,
+	struct v4l2_exportbuffer *eb)
+{
+	struct s5p_mfc_ctx *ctx = fh_to_ctx(priv);
+
+	if (eb->type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE)
+		return vb2_expbuf(&ctx->vq_src, eb);
+	if (eb->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE)
+		return vb2_expbuf(&ctx->vq_dst, eb);
+	return -EINVAL;
+}
+
 /* Stream on */
 static int vidioc_streamon(struct file *file, void *priv,
 			   enum v4l2_buf_type type)
@@ -1568,6 +1581,7 @@ static const struct v4l2_ioctl_ops s5p_mfc_enc_ioctl_ops = {
 	.vidioc_querybuf = vidioc_querybuf,
 	.vidioc_qbuf = vidioc_qbuf,
 	.vidioc_dqbuf = vidioc_dqbuf,
+	.vidioc_expbuf = vidioc_expbuf,
 	.vidioc_streamon = vidioc_streamon,
 	.vidioc_streamoff = vidioc_streamoff,
 	.vidioc_s_parm = vidioc_s_parm,
-- 
1.7.9.5

Re: [PATCHv10 23/26] v4l: vb2-dma-contig: align buffer size to PAGE_SIZE

[Laurent Pinchart]

Hi Tomasz,

On Wednesday 10 October 2012 16:46:42 Tomasz Stanislawski wrote:
> Most operations on DMA and DMABUF framework need page
> aligned buffers.

The comment is a bit misleading, the buffer is already page-aligned (unless 
I'm mistaken dma_alloc_coherent() returns a page-aligned buffer) but its size 
isn't a multiple of the page size.

Do we really need a page size multiple ? Isn't it enough to make the size a 
multiple of the cache line size ?

> This fix guarantees this requirement
> for vb2-dma-contig buffers.
> 
> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
> ---
>  drivers/media/v4l2-core/videobuf2-dma-contig.c |    3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 571a919..002ee50
> 100644
> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> @@ -162,6 +162,9 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned long
> size) if (!buf)
>  		return ERR_PTR(-ENOMEM);
> 
> +	/* align image size to PAGE_SIZE */
> +	size = PAGE_ALIGN(size);
> +
>  	buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr, GFP_KERNEL);
>  	if (!buf->vaddr) {
>  		dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
-- 
Regards,

Laurent Pinchart

Re: [PATCHv10 22/26] v4l: vb2-dma-contig: fail if user ptr buffer is not correctly aligned

[Laurent Pinchart]

Hi Tomasz,

Thanks for the patch.

On Wednesday 10 October 2012 16:46:41 Tomasz Stanislawski wrote:
> From: Marek Szyprowski <m.szyprowski@samsung.com>
> 
> The DMA transfer must be aligned to a specific value. If userptr is not
> aligned to DMA requirements then unexpected corruptions of the memory may
> occur before or after a buffer.  To prevent such situations, all unligned
> userptr buffers are rejected at VIDIOC_QBUF.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
> ---
>  drivers/media/v4l2-core/videobuf2-dma-contig.c |   12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 2d661fd..571a919
> 100644
> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> @@ -493,6 +493,18 @@ static void *vb2_dc_get_userptr(void *alloc_ctx,
> unsigned long vaddr, struct vm_area_struct *vma;
>  	struct sg_table *sgt;
>  	unsigned long contig_size;
> +	unsigned long dma_align = dma_get_cache_alignment();
> +
> +	/* Only cache aligned DMA transfers are reliable */
> +	if (!IS_ALIGNED(vaddr | size, dma_align)) {
> +		pr_debug("user data must be aligned to %lu bytes\n", dma_align);
> +		return ERR_PTR(-EINVAL);
> +	}

Looks good to me.

> +	if (!size) {
> +		pr_debug("size is zero\n");
> +		return ERR_PTR(-EINVAL);
> +	}

Can this happen ? The vb2 core already has

                /* Check if the provided plane buffer is large enough */
                if (planes[plane].length < q->plane_sizes[plane]) {
                        ret = -EINVAL;
                        goto err;
                }

Unless queue_setup sets plane_sizes to 0 we can't reach vb2_dc_get_userptr.

>  	buf = kzalloc(sizeof *buf, GFP_KERNEL);
>  	if (!buf)

-- 
Regards,

Laurent Pinchart

Re: [PATCHv10 20/26] v4l: vb2-dma-contig: add support for DMABUF exporting

[Laurent Pinchart]

Hi Tomasz,

On Wednesday 10 October 2012 16:46:39 Tomasz Stanislawski wrote:
> This patch adds support for exporting a dma-contig buffer using
> DMABUF interface.
> 
> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> Acked-by: Hans Verkuil <hans.verkuil@cisco.com>

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  drivers/media/v4l2-core/videobuf2-dma-contig.c |  200 +++++++++++++++++++++
>  1 file changed, 200 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 0e065ce..b138b5c
> 100644
> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> @@ -36,6 +36,7 @@ struct vb2_dc_buf {
>  	/* MMAP related */
>  	struct vb2_vmarea_handler	handler;
>  	atomic_t			refcount;
> +	struct sg_table			*sgt_base;
> 
>  	/* USERPTR related */
>  	struct vm_area_struct		*vma;
> @@ -142,6 +143,10 @@ static void vb2_dc_put(void *buf_priv)
>  	if (!atomic_dec_and_test(&buf->refcount))
>  		return;
> 
> +	if (buf->sgt_base) {
> +		sg_free_table(buf->sgt_base);
> +		kfree(buf->sgt_base);
> +	}
>  	dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
>  	kfree(buf);
>  }
> @@ -213,6 +218,200 @@ static int vb2_dc_mmap(void *buf_priv, struct
> vm_area_struct *vma) }
> 
>  /*********************************************/
> +/*         DMABUF ops for exporters          */
> +/*********************************************/
> +
> +struct vb2_dc_attachment {
> +	struct sg_table sgt;
> +	enum dma_data_direction dir;
> +};
> +
> +static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device
> *dev, +	struct dma_buf_attachment *dbuf_attach)
> +{
> +	struct vb2_dc_attachment *attach;
> +	unsigned int i;
> +	struct scatterlist *rd, *wr;
> +	struct sg_table *sgt;
> +	struct vb2_dc_buf *buf = dbuf->priv;
> +	int ret;
> +
> +	attach = kzalloc(sizeof(*attach), GFP_KERNEL);
> +	if (!attach)
> +		return -ENOMEM;
> +
> +	sgt = &attach->sgt;
> +	/* Copy the buf->base_sgt scatter list to the attachment, as we can't
> +	 * map the same scatter list to multiple attachments at the same time.
> +	 */
> +	ret = sg_alloc_table(sgt, buf->sgt_base->orig_nents, GFP_KERNEL);
> +	if (ret) {
> +		kfree(attach);
> +		return -ENOMEM;
> +	}
> +
> +	rd = buf->sgt_base->sgl;
> +	wr = sgt->sgl;
> +	for (i = 0; i < sgt->orig_nents; ++i) {
> +		sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
> +		rd = sg_next(rd);
> +		wr = sg_next(wr);
> +	}
> +
> +	attach->dir = DMA_NONE;
> +	dbuf_attach->priv = attach;
> +
> +	return 0;
> +}
> +
> +static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
> +	struct dma_buf_attachment *db_attach)
> +{
> +	struct vb2_dc_attachment *attach = db_attach->priv;
> +	struct sg_table *sgt;
> +
> +	if (!attach)
> +		return;
> +
> +	sgt = &attach->sgt;
> +
> +	/* release the scatterlist cache */
> +	if (attach->dir != DMA_NONE)
> +		dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
> +			attach->dir);
> +	sg_free_table(sgt);
> +	kfree(attach);
> +	db_attach->priv = NULL;
> +}
> +
> +static struct sg_table *vb2_dc_dmabuf_ops_map(
> +	struct dma_buf_attachment *db_attach, enum dma_data_direction dir)
> +{
> +	struct vb2_dc_attachment *attach = db_attach->priv;
> +	/* stealing dmabuf mutex to serialize map/unmap operations */
> +	struct mutex *lock = &db_attach->dmabuf->lock;
> +	struct sg_table *sgt;
> +	int ret;
> +
> +	mutex_lock(lock);
> +
> +	sgt = &attach->sgt;
> +	/* return previously mapped sg table */
> +	if (attach->dir == dir) {
> +		mutex_unlock(lock);
> +		return sgt;
> +	}
> +
> +	/* release any previous cache */
> +	if (attach->dir != DMA_NONE) {
> +		dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
> +			attach->dir);
> +		attach->dir = DMA_NONE;
> +	}
> +
> +	/* mapping to the client with new direction */
> +	ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dir);
> +	if (ret <= 0) {
> +		pr_err("failed to map scatterlist\n");
> +		mutex_unlock(lock);
> +		return ERR_PTR(-EIO);
> +	}
> +
> +	attach->dir = dir;
> +
> +	mutex_unlock(lock);
> +
> +	return sgt;
> +}
> +
> +static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
> +	struct sg_table *sgt, enum dma_data_direction dir)
> +{
> +	/* nothing to be done here */
> +}
> +
> +static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf)
> +{
> +	/* drop reference obtained in vb2_dc_get_dmabuf */
> +	vb2_dc_put(dbuf->priv);
> +}
> +
> +static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long
> pgnum) +{
> +	struct vb2_dc_buf *buf = dbuf->priv;
> +
> +	return buf->vaddr + pgnum * PAGE_SIZE;
> +}
> +
> +static void *vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf)
> +{
> +	struct vb2_dc_buf *buf = dbuf->priv;
> +
> +	return buf->vaddr;
> +}
> +
> +static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf,
> +	struct vm_area_struct *vma)
> +{
> +	return vb2_dc_mmap(dbuf->priv, vma);
> +}
> +
> +static struct dma_buf_ops vb2_dc_dmabuf_ops = {
> +	.attach = vb2_dc_dmabuf_ops_attach,
> +	.detach = vb2_dc_dmabuf_ops_detach,
> +	.map_dma_buf = vb2_dc_dmabuf_ops_map,
> +	.unmap_dma_buf = vb2_dc_dmabuf_ops_unmap,
> +	.kmap = vb2_dc_dmabuf_ops_kmap,
> +	.kmap_atomic = vb2_dc_dmabuf_ops_kmap,
> +	.vmap = vb2_dc_dmabuf_ops_vmap,
> +	.mmap = vb2_dc_dmabuf_ops_mmap,
> +	.release = vb2_dc_dmabuf_ops_release,
> +};
> +
> +static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
> +{
> +	int ret;
> +	struct sg_table *sgt;
> +
> +	sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
> +	if (!sgt) {
> +		dev_err(buf->dev, "failed to alloc sg table\n");
> +		return NULL;
> +	}
> +
> +	ret = dma_get_sgtable(buf->dev, sgt, buf->vaddr, buf->dma_addr,
> +		buf->size);
> +	if (ret < 0) {
> +		dev_err(buf->dev, "failed to get scatterlist from DMA API\n");
> +		kfree(sgt);
> +		return NULL;
> +	}
> +
> +	return sgt;
> +}
> +
> +static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv)
> +{
> +	struct vb2_dc_buf *buf = buf_priv;
> +	struct dma_buf *dbuf;
> +
> +	if (!buf->sgt_base)
> +		buf->sgt_base = vb2_dc_get_base_sgt(buf);
> +
> +	if (WARN_ON(!buf->sgt_base))
> +		return NULL;
> +
> +	dbuf = dma_buf_export(buf, &vb2_dc_dmabuf_ops, buf->size, 0);
> +	if (IS_ERR(dbuf))
> +		return NULL;
> +
> +	/* dmabuf keeps reference to vb2 buffer */
> +	atomic_inc(&buf->refcount);
> +
> +	return dbuf;
> +}
> +
> +/*********************************************/
>  /*       callbacks for USERPTR buffers       */
>  /*********************************************/
> 
> @@ -519,6 +718,7 @@ static void *vb2_dc_attach_dmabuf(void *alloc_ctx,
> struct dma_buf *dbuf, const struct vb2_mem_ops vb2_dma_contig_memops = {
>  	.alloc		= vb2_dc_alloc,
>  	.put		= vb2_dc_put,
> +	.get_dmabuf	= vb2_dc_get_dmabuf,
>  	.cookie		= vb2_dc_cookie,
>  	.vaddr		= vb2_dc_vaddr,
>  	.mmap		= vb2_dc_mmap,
-- 
Regards,

Laurent Pinchart

Re: [PATCHv10 21/26] v4l: vb2-dma-contig: add reference counting for a device from allocator context

[Laurent Pinchart]

Hi Tomasz,

Thanks for the patch.

On Wednesday 10 October 2012 16:46:40 Tomasz Stanislawski wrote:
> This patch adds taking reference to the device for MMAP buffers.
> 
> Such buffers, may be exported using DMABUF mechanism. If the driver that
> created a queue is unloaded then the queue is released, the device might be
> released too.  However, buffers cannot be released if they are referenced by
> DMABUF descriptor(s). The device pointer kept in a buffer must be valid for
> the whole buffer's lifetime. Therefore MMAP buffers should take a reference
> to the device to avoid risk of dangling pointers.
> 
> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
> Acked-by: Hans Verkuil <hans.verkuil@cisco.com>

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

But two small comments below.

> ---
>  drivers/media/v4l2-core/videobuf2-dma-contig.c |    4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> b/drivers/media/v4l2-core/videobuf2-dma-contig.c index b138b5c..2d661fd
> 100644
> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> @@ -148,6 +148,7 @@ static void vb2_dc_put(void *buf_priv)
>  		kfree(buf->sgt_base);
>  	}
>  	dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
> +	put_device(buf->dev);
>  	kfree(buf);
>  }
> 
> @@ -168,6 +169,9 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned long
> size) return ERR_PTR(-ENOMEM);
>  	}
> 
> +	/* prevent the device from release while the buffer is exported */

s/prevent/Prevent/ ?

> +	get_device(dev);
> +
>  	buf->dev = dev;

What about just

	buf->dev = get_device(dev);

>  	buf->size = size;
-- 
Regards,

Laurent Pinchart

Re: [PATCHv10 21/26] v4l: vb2-dma-contig: add reference counting for a device from allocator context

[Tomasz Stanislawski]

Hi Laurent,
Thank your your review.

On 10/11/2012 11:49 PM, Laurent Pinchart wrote:
> Hi Tomasz,
> 
> Thanks for the patch.
> 
> On Wednesday 10 October 2012 16:46:40 Tomasz Stanislawski wrote:
>> This patch adds taking reference to the device for MMAP buffers.
>>
>> Such buffers, may be exported using DMABUF mechanism. If the driver that
>> created a queue is unloaded then the queue is released, the device might be
>> released too.  However, buffers cannot be released if they are referenced by
>> DMABUF descriptor(s). The device pointer kept in a buffer must be valid for
>> the whole buffer's lifetime. Therefore MMAP buffers should take a reference
>> to the device to avoid risk of dangling pointers.
>>
>> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
>> Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
> 
> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> But two small comments below.
> 
>> ---
>>  drivers/media/v4l2-core/videobuf2-dma-contig.c |    4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c
>> b/drivers/media/v4l2-core/videobuf2-dma-contig.c index b138b5c..2d661fd
>> 100644
>> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
>> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
>> @@ -148,6 +148,7 @@ static void vb2_dc_put(void *buf_priv)
>>  		kfree(buf->sgt_base);
>>  	}
>>  	dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
>> +	put_device(buf->dev);
>>  	kfree(buf);
>>  }
>>
>> @@ -168,6 +169,9 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned long
>> size) return ERR_PTR(-ENOMEM);
>>  	}
>>
>> +	/* prevent the device from release while the buffer is exported */
> 
> s/prevent/Prevent/ ?
> 

s/release/being released/ ?

>> +	get_device(dev);
>> +
>>  	buf->dev = dev;
> 
> What about just
> 
> 	buf->dev = get_device(dev);
> 

Right, sorry I missed that from your previous review :).

Regards,
Tomasz Stanislawski

>>  	buf->size = size;

Re: [PATCHv10 22/26] v4l: vb2-dma-contig: fail if user ptr buffer is not correctly aligned

[Tomasz Stanislawski]

Hi Laurent,
Thank you for the review.
Please refer to the comments below.

On 10/11/2012 11:36 PM, Laurent Pinchart wrote:
> Hi Tomasz,
> 
> Thanks for the patch.
> 
> On Wednesday 10 October 2012 16:46:41 Tomasz Stanislawski wrote:
>> From: Marek Szyprowski <m.szyprowski@samsung.com>
>>
>> The DMA transfer must be aligned to a specific value. If userptr is not
>> aligned to DMA requirements then unexpected corruptions of the memory may
>> occur before or after a buffer.  To prevent such situations, all unligned
>> userptr buffers are rejected at VIDIOC_QBUF.
>>
>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>> Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
>> ---
>>  drivers/media/v4l2-core/videobuf2-dma-contig.c |   12 ++++++++++++
>>  1 file changed, 12 insertions(+)
>>
>> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c
>> b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 2d661fd..571a919
>> 100644
>> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
>> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
>> @@ -493,6 +493,18 @@ static void *vb2_dc_get_userptr(void *alloc_ctx,
>> unsigned long vaddr, struct vm_area_struct *vma;
>>  	struct sg_table *sgt;
>>  	unsigned long contig_size;
>> +	unsigned long dma_align = dma_get_cache_alignment();
>> +
>> +	/* Only cache aligned DMA transfers are reliable */
>> +	if (!IS_ALIGNED(vaddr | size, dma_align)) {
>> +		pr_debug("user data must be aligned to %lu bytes\n", dma_align);
>> +		return ERR_PTR(-EINVAL);
>> +	}
> 
> Looks good to me.
> 
>> +	if (!size) {
>> +		pr_debug("size is zero\n");
>> +		return ERR_PTR(-EINVAL);
>> +	}
> 
> Can this happen ? The vb2 core already has
> 
>                 /* Check if the provided plane buffer is large enough */
>                 if (planes[plane].length < q->plane_sizes[plane]) {
>                         ret = -EINVAL;
>                         goto err;
>                 }
> 
> Unless queue_setup sets plane_sizes to 0 we can't reach vb2_dc_get_userptr.
> 

Yes.. unfortunately, some drivers set plane_size to 0 at queue_setup.
Especially, if REQBUFS is called before any S_FMT.
Maybe it is just a driver bug.

However, VB2 makes no sanity check if plane_sizes[] is zero.
I was not able to find in Documentation nor code comments
any explicit statement that plane_size cannot be zero.

Therefore I have to reject reject a 0-bytes-long user pointer
at vb2_dc_get_userptr before creating an empty scatterlist
and passing it to the DMA layer.

Regards,
Tomasz Stanislawski

>>  	buf = kzalloc(sizeof *buf, GFP_KERNEL);
>>  	if (!buf)
> 

Re: [PATCHv10 22/26] v4l: vb2-dma-contig: fail if user ptr buffer is not correctly aligned

[Hans Verkuil]

On Fri 12 October 2012 09:44:05 Tomasz Stanislawski wrote:
> Hi Laurent,
> Thank you for the review.
> Please refer to the comments below.
> 
> On 10/11/2012 11:36 PM, Laurent Pinchart wrote:
> > Hi Tomasz,
> > 
> > Thanks for the patch.
> > 
> > On Wednesday 10 October 2012 16:46:41 Tomasz Stanislawski wrote:
> >> From: Marek Szyprowski <m.szyprowski@samsung.com>
> >>
> >> The DMA transfer must be aligned to a specific value. If userptr is not
> >> aligned to DMA requirements then unexpected corruptions of the memory may
> >> occur before or after a buffer.  To prevent such situations, all unligned
> >> userptr buffers are rejected at VIDIOC_QBUF.
> >>
> >> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> >> Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
> >> ---
> >>  drivers/media/v4l2-core/videobuf2-dma-contig.c |   12 ++++++++++++
> >>  1 file changed, 12 insertions(+)
> >>
> >> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> >> b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 2d661fd..571a919
> >> 100644
> >> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> >> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> >> @@ -493,6 +493,18 @@ static void *vb2_dc_get_userptr(void *alloc_ctx,
> >> unsigned long vaddr, struct vm_area_struct *vma;
> >>  	struct sg_table *sgt;
> >>  	unsigned long contig_size;
> >> +	unsigned long dma_align = dma_get_cache_alignment();
> >> +
> >> +	/* Only cache aligned DMA transfers are reliable */
> >> +	if (!IS_ALIGNED(vaddr | size, dma_align)) {
> >> +		pr_debug("user data must be aligned to %lu bytes\n", dma_align);
> >> +		return ERR_PTR(-EINVAL);
> >> +	}
> > 
> > Looks good to me.
> > 
> >> +	if (!size) {
> >> +		pr_debug("size is zero\n");
> >> +		return ERR_PTR(-EINVAL);
> >> +	}
> > 
> > Can this happen ? The vb2 core already has
> > 
> >                 /* Check if the provided plane buffer is large enough */
> >                 if (planes[plane].length < q->plane_sizes[plane]) {
> >                         ret = -EINVAL;
> >                         goto err;
> >                 }
> > 
> > Unless queue_setup sets plane_sizes to 0 we can't reach vb2_dc_get_userptr.
> > 
> 
> Yes.. unfortunately, some drivers set plane_size to 0 at queue_setup.
> Especially, if REQBUFS is called before any S_FMT.
> Maybe it is just a driver bug.

That's a driver bug. Planes with size 0 make no sense whatsoever. vb2 should
WARN_ON on that and return an error.

My guess is that these drivers do not set up a default format as they should.

Regards,

	Hans

> However, VB2 makes no sanity check if plane_sizes[] is zero.
> I was not able to find in Documentation nor code comments
> any explicit statement that plane_size cannot be zero.
> 
> Therefore I have to reject reject a 0-bytes-long user pointer
> at vb2_dc_get_userptr before creating an empty scatterlist
> and passing it to the DMA layer.
> 
> Regards,
> Tomasz Stanislawski
> 
> >>  	buf = kzalloc(sizeof *buf, GFP_KERNEL);
> >>  	if (!buf)
> > 
> 

Re: [PATCHv10 23/26] v4l: vb2-dma-contig: align buffer size to PAGE_SIZE

[Tomasz Stanislawski]

Hi Laurent,

On 10/11/2012 11:31 PM, Laurent Pinchart wrote:
> Hi Tomasz,
> 
> On Wednesday 10 October 2012 16:46:42 Tomasz Stanislawski wrote:
>> Most operations on DMA and DMABUF framework need page
>> aligned buffers.
> 
> The comment is a bit misleading, the buffer is already page-aligned (unless 
> I'm mistaken dma_alloc_coherent() returns a page-aligned buffer) but its size 
> isn't a multiple of the page size.

Ok. I will update the commit message that only buffer size is going to be page aligned.

> 
> Do we really need a page size multiple ? Isn't it enough to make the size a 
> multiple of the cache line size ?
> 

Frankly, I strongly oppose forcing a size of a DMA buffer to be rounded up.

However, I discovered a problem while testing mmap() interface in dma-buf.
The test in dma_buf_mmap() will fail if the size is not a multiple of 4k.

Maybe the value from dma-buf.c:456 should be changed from:

dmabuf->size >> PAGE_SHIFT

to

PAGE_ALIGN(dmabuf->size) >> PAGE_SHIFT

However, I preferred to avoid any changes outside of the media tree
hoping that the patchset gets merged. Rounding the buffer size to
a page size was quick workaround for the issue with DMABUF mmap().

Regards,
Tomasz Stanislawski

>> This fix guarantees this requirement
>> for vb2-dma-contig buffers.
>>
>> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
>> ---
>>  drivers/media/v4l2-core/videobuf2-dma-contig.c |    3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c
>> b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 571a919..002ee50
>> 100644
>> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
>> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
>> @@ -162,6 +162,9 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned long
>> size) if (!buf)
>>  		return ERR_PTR(-ENOMEM);
>>
>> +	/* align image size to PAGE_SIZE */
>> +	size = PAGE_ALIGN(size);
>> +
>>  	buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr, GFP_KERNEL);
>>  	if (!buf->vaddr) {
>>  		dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);

Re: [PATCHv10 21/26] v4l: vb2-dma-contig: add reference counting for a device from allocator context

[Laurent Pinchart]

Hi Tomasz,

On Friday 12 October 2012 08:28:23 Tomasz Stanislawski wrote:
> On 10/11/2012 11:49 PM, Laurent Pinchart wrote:
> > On Wednesday 10 October 2012 16:46:40 Tomasz Stanislawski wrote:
> >> This patch adds taking reference to the device for MMAP buffers.
> >> 
> >> Such buffers, may be exported using DMABUF mechanism. If the driver that
> >> created a queue is unloaded then the queue is released, the device might
> >> be
> >> released too.  However, buffers cannot be released if they are referenced
> >> by DMABUF descriptor(s). The device pointer kept in a buffer must be
> >> valid for the whole buffer's lifetime. Therefore MMAP buffers should
> >> take a reference to the device to avoid risk of dangling pointers.
> >> 
> >> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
> >> Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
> > 
> > Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > 
> > But two small comments below.
> > 
> >> ---
> >> 
> >>  drivers/media/v4l2-core/videobuf2-dma-contig.c |    4 ++++
> >>  1 file changed, 4 insertions(+)
> >> 
> >> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> >> b/drivers/media/v4l2-core/videobuf2-dma-contig.c index b138b5c..2d661fd
> >> 100644
> >> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> >> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> >> @@ -148,6 +148,7 @@ static void vb2_dc_put(void *buf_priv)
> >>  		kfree(buf->sgt_base);
> >>  	}
> >>  	dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
> >> +	put_device(buf->dev);
> >>  	kfree(buf);
> >>  }
> >> 
> >> @@ -168,6 +169,9 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned
> >> long size)
> >>  		return ERR_PTR(-ENOMEM);
> >>  	}
> >> 
> >> +	/* prevent the device from release while the buffer is exported */
> > 
> > s/prevent/Prevent/ ?
> 
> s/release/being released/ ?

Oops. Of course :-)

> >> +	get_device(dev);
> >> +
> >>  	buf->dev = dev;
> > 
> > What about just
> > 
> > 	buf->dev = get_device(dev);
> 
> Right, sorry I missed that from your previous review :).

-- 
Regards,

Laurent Pinchart

Re: [PATCHv10 22/26] v4l: vb2-dma-contig: fail if user ptr buffer is not correctly aligned

[Laurent Pinchart]

Hi Tomasz,

On Friday 12 October 2012 09:44:05 Tomasz Stanislawski wrote:
> On 10/11/2012 11:36 PM, Laurent Pinchart wrote:
> > On Wednesday 10 October 2012 16:46:41 Tomasz Stanislawski wrote:
> >> From: Marek Szyprowski <m.szyprowski@samsung.com>
> >> 
> >> The DMA transfer must be aligned to a specific value. If userptr is not
> >> aligned to DMA requirements then unexpected corruptions of the memory may
> >> occur before or after a buffer.  To prevent such situations, all unligned
> >> userptr buffers are rejected at VIDIOC_QBUF.
> >> 
> >> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> >> Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
> >> ---
> >> 
> >>  drivers/media/v4l2-core/videobuf2-dma-contig.c |   12 ++++++++++++
> >>  1 file changed, 12 insertions(+)
> >> 
> >> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> >> b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 2d661fd..571a919
> >> 100644
> >> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> >> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> >> @@ -493,6 +493,18 @@ static void *vb2_dc_get_userptr(void *alloc_ctx,
> >> unsigned long vaddr, struct vm_area_struct *vma;
> >> 
> >>  	struct sg_table *sgt;
> >>  	unsigned long contig_size;
> >> 
> >> +	unsigned long dma_align = dma_get_cache_alignment();
> >> +
> >> +	/* Only cache aligned DMA transfers are reliable */
> >> +	if (!IS_ALIGNED(vaddr | size, dma_align)) {
> >> +		pr_debug("user data must be aligned to %lu bytes\n", dma_align);
> >> +		return ERR_PTR(-EINVAL);
> >> +	}
> > 
> > Looks good to me.
> > 
> >> +	if (!size) {
> >> +		pr_debug("size is zero\n");
> >> +		return ERR_PTR(-EINVAL);
> >> +	}
> > 
> > Can this happen ? The vb2 core already has
> > 
> >                 /* Check if the provided plane buffer is large enough */
> >                 if (planes[plane].length < q->plane_sizes[plane]) {
> >                 
> >                         ret = -EINVAL;
> >                         goto err;
> >                 
> >                 }
> > 
> > Unless queue_setup sets plane_sizes to 0 we can't reach
> > vb2_dc_get_userptr.
> 
> Yes.. unfortunately, some drivers set plane_size to 0 at queue_setup.
> Especially, if REQBUFS is called before any S_FMT.
> Maybe it is just a driver bug.
> 
> However, VB2 makes no sanity check if plane_sizes[] is zero.
> I was not able to find in Documentation nor code comments
> any explicit statement that plane_size cannot be zero.
> 
> Therefore I have to reject reject a 0-bytes-long user pointer
> at vb2_dc_get_userptr before creating an empty scatterlist
> and passing it to the DMA layer.

Wouldn't it then be better to add the sanity checks in the core ?

> >>  	buf = kzalloc(sizeof *buf, GFP_KERNEL);
> >>  	if (!buf)

-- 
Regards,

Laurent Pinchart

Re: [PATCHv10 02/26] Documentation: media: description of DMABUF importing in V4L2

[Hans Verkuil]

On Wed October 10 2012 16:46:21 Tomasz Stanislawski wrote:
> This patch adds description and usage examples for importing
> DMABUF file descriptor in V4L2.
> 
> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> CC: linux-doc@vger.kernel.org
> ---
>  Documentation/DocBook/media/v4l/compat.xml         |    4 +
>  Documentation/DocBook/media/v4l/io.xml             |  181 +++++++++++++++++++-
>  .../DocBook/media/v4l/vidioc-create-bufs.xml       |   16 +-
>  Documentation/DocBook/media/v4l/vidioc-qbuf.xml    |   17 ++
>  Documentation/DocBook/media/v4l/vidioc-reqbufs.xml |   47 ++---
>  5 files changed, 235 insertions(+), 30 deletions(-)
> 

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>

Re: [PATCHv10 17/26] Documentation: media: description of DMABUF exporting in V4L2

[Hans Verkuil]

On Wed October 10 2012 16:46:36 Tomasz Stanislawski wrote:
> This patch adds description and usage examples for exporting
> DMABUF file descriptor in V4L2.
> 
> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> CC: linux-doc@vger.kernel.org
> ---
>  Documentation/DocBook/media/v4l/compat.xml        |    3 +
>  Documentation/DocBook/media/v4l/io.xml            |    3 +
>  Documentation/DocBook/media/v4l/v4l2.xml          |    1 +
>  Documentation/DocBook/media/v4l/vidioc-expbuf.xml |  212 +++++++++++++++++++++
>  4 files changed, 219 insertions(+)
>  create mode 100644 Documentation/DocBook/media/v4l/vidioc-expbuf.xml
> 

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>

Re: [PATCHv10 18/26] v4l: add buffer exporting via dmabuf

[Hans Verkuil]

On Wed October 10 2012 16:46:37 Tomasz Stanislawski wrote:
> This patch adds extension to V4L2 api. It allow to export a mmap buffer as file
> descriptor. New ioctl VIDIOC_EXPBUF is added. It takes a buffer offset used by
> mmap and return a file descriptor on success.
> 
> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> ---
>  drivers/media/v4l2-core/v4l2-compat-ioctl32.c |    1 +
>  drivers/media/v4l2-core/v4l2-dev.c            |    1 +
>  drivers/media/v4l2-core/v4l2-ioctl.c          |   10 +++++++++
>  include/linux/videodev2.h                     |   28 +++++++++++++++++++++++++
>  include/media/v4l2-ioctl.h                    |    2 ++
>  5 files changed, 42 insertions(+)

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>

Re: [PATCHv10 23/26] v4l: vb2-dma-contig: align buffer size to PAGE_SIZE

[Laurent Pinchart]

Hi Tomasz,

On Friday 12 October 2012 10:24:34 Tomasz Stanislawski wrote:
> On 10/11/2012 11:31 PM, Laurent Pinchart wrote:
> > On Wednesday 10 October 2012 16:46:42 Tomasz Stanislawski wrote:
> >> Most operations on DMA and DMABUF framework need page
> >> aligned buffers.
> > 
> > The comment is a bit misleading, the buffer is already page-aligned
> > (unless I'm mistaken dma_alloc_coherent() returns a page-aligned buffer)
> > but its size isn't a multiple of the page size.
> 
> Ok. I will update the commit message that only buffer size is going to be
> page aligned.
>
> > Do we really need a page size multiple ? Isn't it enough to make the size
> > a multiple of the cache line size ?
> 
> Frankly, I strongly oppose forcing a size of a DMA buffer to be rounded up.
> 
> However, I discovered a problem while testing mmap() interface in dma-buf.
> The test in dma_buf_mmap() will fail if the size is not a multiple of 4k.
> 
> Maybe the value from dma-buf.c:456 should be changed from:
> 
> dmabuf->size >> PAGE_SHIFT
> 
> to
> 
> PAGE_ALIGN(dmabuf->size) >> PAGE_SHIFT
> 
> However, I preferred to avoid any changes outside of the media tree hoping
> that the patchset gets merged. Rounding the buffer size to a page size was
> quick workaround for the issue with DMABUF mmap().

After some more thoughts I'm not sure whether this patch does the right thing. 
We have two sizes that we neeed to care about, the user usable buffer size and 
the allocated memory size.

When a user of a buffer requests buffer allocation with an explicit or 
implicit size we might need to allocate a larger buffer to fulfill usage 
requirements. We can thus end up with an allocated memory size larger than 
what the user requested. Such usage requirements include

- DMA and CPU access: when accessing the buffer both through DMA and directly 
by the CPU cache management comes into play, and the buffer address and size 
then need to be aligned to a cache line size boundary.

- Mapping to userspace: we can only map complete pages to userspace, the 
buffer address and size need to be aligned to a page size boundary to make 
sure that we won't leak unrelated data to userspace.

As the cache line size is smaller than a page fulfilling the second 
requirement always fulfills the first. There might be other requirements that 
escape my mind right now.

As we don't precisely know at allocation time how the buffer will be used (for 
instance whether it will eventually be mapped to userspace or not), we have 
two options:

- Align the buffer size to a page size boundary unconditionally.

- Let the user handle that requirement by specifying an allocation size 
aligned to a page size boundary.

Given the complexity associated with the second solution and the very small, 
if not inexistent, expected memory gain (when using the DMA allocation APIs we 
always get complete pages anyway, so there would be no gain in not aligning 
the allocation size to a page size boundary), I think the first solution 
should be preferred.

This leaves us with two questions related to buffer size: what size (between 
the requested size and the actually allocated size) do we report back to the 
user (in the v4l2_buffer length field for instance), and what size do we 
report to the dma-buf core (and thus to the other subsystems and other buffer 
users) ?

-- 
Regards,

Laurent Pinchart

Re: [PATCHv10 08/26] v4l: vb2-dma-contig: add support for scatterlist in userptr mode

[Pawel Osciak]

Hi Tomasz,

On Wed, Oct 10, 2012 at 7:46 AM, Tomasz Stanislawski
<t.stanislaws@samsung.com> wrote:
> This patch introduces usage of dma_map_sg to map memory behind
> a userspace pointer to a device as dma-contiguous mapping.
>

Perhaps I'm missing something, but I don't understand the purpose of
this patch. If the device can do DMA SG, why use videobuf2-dma-contig
and not videobuf2-dma-sg? What would be the difference design-wise
between them if this patch is merged?

-- 
Best regards,
Pawel Osciak

Re: [PATCHv10 08/26] v4l: vb2-dma-contig: add support for scatterlist in userptr mode

[Marek Szyprowski]

Hello,

On 10/26/2012 6:24 PM, Pawel Osciak wrote:
> Hi Tomasz,
>
> On Wed, Oct 10, 2012 at 7:46 AM, Tomasz Stanislawski
> <t.stanislaws@samsung.com> wrote:
>> This patch introduces usage of dma_map_sg to map memory behind
>> a userspace pointer to a device as dma-contiguous mapping.
>>
>
> Perhaps I'm missing something, but I don't understand the purpose of
> this patch. If the device can do DMA SG, why use videobuf2-dma-contig
> and not videobuf2-dma-sg?

This patch is for devices which doesn't do DMA SG, but might be behind 
IOMMU. In such case one can call dma_map_sg() with scatterlist of 
individual pages gathered from user pointer (anonymous memory of the 
process) which in turn will be mapped into contiguous dma adress space 
(dma_map_sg() returns only one chunk in such case). This is not very 
intuitive, but it was best way to fit such case into existing 
dma-mapping design.

> What would be the difference design-wise
> between them if this patch is merged?

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center

[PATCH 27/26] v4l: vb2: Set data_offset to 0 for single-plane buffers

[Laurent Pinchart]

Single-planar V4L2 buffers are converted to multi-planar vb2 buffers
with a single plane when queued. The plane data_offset field is not
available in the single-planar API and must be set to 0 for dmabuf
buffers and all output buffers.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/media/v4l2-core/videobuf2-core.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index b0402f2..3eae3d8 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -931,6 +931,7 @@ static int __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b,
 		 */
 		if (V4L2_TYPE_IS_OUTPUT(b->type))
 			v4l2_planes[0].bytesused = b->bytesused;
+			v4l2_planes[0].data_offset = 0;
 
 		if (b->memory == V4L2_MEMORY_USERPTR) {
 			v4l2_planes[0].m.userptr = b->m.userptr;
@@ -940,6 +941,7 @@ static int __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b,
 		if (b->memory == V4L2_MEMORY_DMABUF) {
 			v4l2_planes[0].m.fd = b->m.fd;
 			v4l2_planes[0].length = b->length;
+			v4l2_planes[0].data_offset = 0;
 		}
 
 	}
-- 
Regards,

Laurent Pinchart

Re: [PATCH 27/26] v4l: vb2: Set data_offset to 0 for single-plane buffers

[Marek Szyprowski]

Hello,

On 11/8/2012 1:05 PM, Laurent Pinchart wrote:
> Single-planar V4L2 buffers are converted to multi-planar vb2 buffers
> with a single plane when queued. The plane data_offset field is not
> available in the single-planar API and must be set to 0 for dmabuf
> buffers and all output buffers.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>

> ---
>   drivers/media/v4l2-core/videobuf2-core.c |    2 ++
>   1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
> index b0402f2..3eae3d8 100644
> --- a/drivers/media/v4l2-core/videobuf2-core.c
> +++ b/drivers/media/v4l2-core/videobuf2-core.c
> @@ -931,6 +931,7 @@ static int __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b,
>   		 */
>   		if (V4L2_TYPE_IS_OUTPUT(b->type))
>   			v4l2_planes[0].bytesused = b->bytesused;
> +			v4l2_planes[0].data_offset = 0;
>   
>   		if (b->memory == V4L2_MEMORY_USERPTR) {
>   			v4l2_planes[0].m.userptr = b->m.userptr;
> @@ -940,6 +941,7 @@ static int __fill_vb2_buffer(struct vb2_buffer *vb, const struct v4l2_buffer *b,
>   		if (b->memory == V4L2_MEMORY_DMABUF) {
>   			v4l2_planes[0].m.fd = b->m.fd;
>   			v4l2_planes[0].length = b->length;
> +			v4l2_planes[0].data_offset = 0;
>   		}
>   
>   	}

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center

Re: [PATCH 27/26] v4l: vb2: Set data_offset to 0 for single-plane buffers

[Laurent Pinchart]

Hello,

On Thursday 08 November 2012 13:13:50 Marek Szyprowski wrote:
> On 11/8/2012 1:05 PM, Laurent Pinchart wrote:
> > Single-planar V4L2 buffers are converted to multi-planar vb2 buffers
> > with a single plane when queued. The plane data_offset field is not
> > available in the single-planar API and must be set to 0 for dmabuf
> > buffers and all output buffers.
> > 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>

Thank you.

Tomasz, could you please take this in your dma-buf branch ? Sorry for 
forgetting to CC you on the patch.

> > ---
> > 
> >   drivers/media/v4l2-core/videobuf2-core.c |    2 ++
> >   1 files changed, 2 insertions(+), 0 deletions(-)
> > 
> > diff --git a/drivers/media/v4l2-core/videobuf2-core.c
> > b/drivers/media/v4l2-core/videobuf2-core.c index b0402f2..3eae3d8 100644
> > --- a/drivers/media/v4l2-core/videobuf2-core.c
> > +++ b/drivers/media/v4l2-core/videobuf2-core.c
> > @@ -931,6 +931,7 @@ static int __fill_vb2_buffer(struct vb2_buffer *vb,
> > const struct v4l2_buffer *b,> 
> >   		 */
> >   		
> >   		if (V4L2_TYPE_IS_OUTPUT(b->type))
> >   		
> >   			v4l2_planes[0].bytesused = b->bytesused;
> > 
> > +			v4l2_planes[0].data_offset = 0;
> > 
> >   		if (b->memory == V4L2_MEMORY_USERPTR) {
> >   		
> >   			v4l2_planes[0].m.userptr = b->m.userptr;
> > 
> > @@ -940,6 +941,7 @@ static int __fill_vb2_buffer(struct vb2_buffer *vb,
> > const struct v4l2_buffer *b,> 
> >   		if (b->memory == V4L2_MEMORY_DMABUF) {
> >   		
> >   			v4l2_planes[0].m.fd = b->m.fd;
> >   			v4l2_planes[0].length = b->length;
> > 
> > +			v4l2_planes[0].data_offset = 0;
> > 
> >   		}
> >   	
> >   	}

-- 
Regards,

Laurent Pinchart

Re: [PATCH 27/26] v4l: vb2: Set data_offset to 0 for single-plane buffers

[Tomasz Stanislawski]

Hi Laurent,
The fix was partially applied in "[PATCHv10 03/26] v4l: vb2: add support for shared buffer (dma_buf)".
The data_offset is set to 0 for DMABUF capture/output for single-planar API.

We should define the meaning of data_offset in case of USERPTR and MMAP buffers.
For output device it is pretty intuitive.

For DMABUF capture devices data_offset maybe used to inform a driver to
capture the image at some offset inside the DMABUF buffer.

BTW. Should {} be added after "if (V4L2_TYPE_IS_OUTPUT(b->type))"
to avoid 'interesting' behavior? :)

Regards,
Tomasz Stanislawski

Re: [PATCH 27/26] v4l: vb2: Set data_offset to 0 for single-plane buffers

[Laurent Pinchart]

Hi Tomasz,

On Thursday 08 November 2012 16:28:12 Tomasz Stanislawski wrote:
> Hi Laurent,
> The fix was partially applied in "[PATCHv10 03/26] v4l: vb2: add support for
> shared buffer (dma_buf)". The data_offset is set to 0 for DMABUF
> capture/output for single-planar API.

My bad, I had an old version of your patch set in my git tree. The other half 
of the patch should still be applied, but it can go through Mauro's tree 
without going through yours.

> We should define the meaning of data_offset in case of USERPTR and MMAP
> buffers. For output device it is pretty intuitive.
> 
> For DMABUF capture devices data_offset maybe used to inform a driver to
> capture the image at some offset inside the DMABUF buffer.

That's indeed missing from the documentation.

> BTW. Should {} be added after "if (V4L2_TYPE_IS_OUTPUT(b->type))"
> to avoid 'interesting' behavior? :)

Oops :-) I'll fix that.

-- 
Regards,

Laurent Pinchart