[PATCH v3] V4L: add two new ioctl()s for multi-size videobuffer management

A possibility to preallocate and initialise buffers of different sizes
in V4L2 is required for an efficient implementation of asnapshot mode.
This patch adds two new ioctl()s: VIDIOC_CREATE_BUFS and
VIDIOC_PREPARE_BUF and defines respective data structures.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
---

It's been almost a month since v2, the only comments were a request to 
increase the reserved space in the new ioctl() and to improve 
documentation. The reserved field is increased in this version, 
documentation also has been improved in multiple locations. I think, 
documentation can be further improved at any time, but if there are no 
objections against the actual contents of this patch, maybe we can commit 
this version. I still don't see v3.0;-), so, maybe we even can push it for 
3.1. A trivial comparison with v2 shows the size of the reserved field as 
the only change in the API, and the compatibility fix as the only two 
functional changes.

v3: addressed multiple comments by Sakari Ailus

1. increased reserved field in "struct v4l2_create_buffers" to 8 32-bit 
   ints
2. multiple documentation fixes and improvements
3. fixed misplaced "case VIDIOC_PREPARE_BUF" in ioctl 32-bit compatibility 
   processing

v2:

1. add preliminary Documentation
2. add flag V4L2_BUFFER_FLAG_NO_CACHE_CLEAN
3. remove VIDIOC_DESTROY_BUFS
4. rename SUBMIT to VIDIOC_PREPARE_BUF
5. add reserved field to struct v4l2_create_buffers
6. cache handling flags moved to struct v4l2_buffer for processing during 
   VIDIOC_PREPARE_BUF
7. VIDIOC_PREPARE_BUF now uses struct v4l2_buffer as its argument


 Documentation/DocBook/media/v4l/io.xml             |   17 +++
 Documentation/DocBook/media/v4l/v4l2.xml           |    2 +
 .../DocBook/media/v4l/vidioc-create-bufs.xml       |  152 ++++++++++++++++++++
 .../DocBook/media/v4l/vidioc-prepare-buf.xml       |   96 ++++++++++++
 drivers/media/video/v4l2-compat-ioctl32.c          |   68 ++++++++-
 drivers/media/video/v4l2-ioctl.c                   |   32 ++++
 include/linux/videodev2.h                          |   16 ++
 include/media/v4l2-ioctl.h                         |    2 +
 8 files changed, 377 insertions(+), 8 deletions(-)
 create mode 100644 Documentation/DocBook/media/v4l/vidioc-create-bufs.xml
 create mode 100644 Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml

diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml
index 227e7ac..6249d0e 100644
--- a/Documentation/DocBook/media/v4l/io.xml
+++ b/Documentation/DocBook/media/v4l/io.xml
@@ -927,6 +927,23 @@ ioctl is called.</entry>
 Applications set or clear this flag before calling the
 <constant>VIDIOC_QBUF</constant> ioctl.</entry>
 	  </row>
+	  <row>
+	    <entry><constant>V4L2_BUF_FLAG_NO_CACHE_INVALIDATE</constant></entry>
+	    <entry>0x0400</entry>
+	    <entry>Caches do not have to be invalidated for this buffer.
+Typically applications shall use this flag, if the data, captured in the buffer
+is not going to br touched by the CPU, instead the buffer will, probably, be
+passed on to a DMA-capable hardware unit for further processing or output.
+</entry>
+	  </row>
+	  <row>
+	    <entry><constant>V4L2_BUF_FLAG_NO_CACHE_CLEAN</constant></entry>
+	    <entry>0x0800</entry>
+	    <entry>Caches do not have to be cleaned for this buffer.
+Typically applications shall use this flag for output buffers, if the data
+in this buffer has not been created by the CPU, but by some DMA-capable unit,
+in which case caches have not been used.</entry>
+	  </row>
 	</tbody>
       </tgroup>
     </table>
diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml
index 0d05e87..06bb179 100644
--- a/Documentation/DocBook/media/v4l/v4l2.xml
+++ b/Documentation/DocBook/media/v4l/v4l2.xml
@@ -462,6 +462,7 @@ and discussions on the V4L mailing list.</revremark>
     &sub-close;
     &sub-ioctl;
     <!-- All ioctls go here. -->
+    &sub-create-bufs;
     &sub-cropcap;
     &sub-dbg-g-chip-ident;
     &sub-dbg-g-register;
@@ -504,6 +505,7 @@ and discussions on the V4L mailing list.</revremark>
     &sub-queryctrl;
     &sub-query-dv-preset;
     &sub-querystd;
+    &sub-prepare-buf;
     &sub-reqbufs;
     &sub-s-hw-freq-seek;
     &sub-streamon;
diff --git a/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml b/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml
new file mode 100644
index 0000000..5f0158c
--- /dev/null
+++ b/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml
@@ -0,0 +1,152 @@
+<refentry id="vidioc-create-bufs">
+  <refmeta>
+    <refentrytitle>ioctl VIDIOC_CREATE_BUFS</refentrytitle>
+    &manvol;
+  </refmeta>
+
+  <refnamediv>
+    <refname>VIDIOC_CREATE_BUFS</refname>
+    <refpurpose>Create buffers for Memory Mapped or User Pointer I/O</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_create_buffers *<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_CREATE_BUFS</para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><parameter>argp</parameter></term>
+	<listitem>
+	  <para></para>
+	</listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+
+  <refsect1>
+    <title>Description</title>
+
+    <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 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>To allocate device buffers applications initialize all
+fields of the <structname>v4l2_create_buffers</structname> structure.
+They set the <structfield>type</structfield> field in the
+<structname>v4l2_format</structname> structure, embedded in this
+structure, to the respective stream or buffer type.
+<structfield>count</structfield> must be set to the number of required
+buffers. <structfield>memory</structfield> specifies the required I/O
+method. Applications have two possibilities to specify the size of buffers
+to be prepared: they can either set the <structfield>size</structfield>
+field explicitly to a non-zero value, or fill in the frame format data in the
+<structfield>format</structfield> field. In the latter case buffer sizes
+will be calculated automatically by the driver. 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
+up to the requested number of buffers and store the actual number allocated
+and the starting index in the <structfield>count</structfield> and
+the <structfield>index</structfield> fields respectively.
+<structfield>count</structfield> can be smaller than the number requested.
+-ENOMEM is returned, if the driver runs out of free memory.</para>
+    <para>When the I/O method is not supported the ioctl
+returns an &EINVAL;.</para>
+
+    <table pgwide="1" frame="none" id="v4l2-create-buffers">
+      <title>struct <structname>v4l2_create_buffers</structname></title>
+      <tgroup cols="3">
+	&cs-str;
+	<tbody valign="top">
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>index</structfield></entry>
+	    <entry>The starting buffer index, returned by the driver.</entry>
+	  </row>
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>count</structfield></entry>
+	    <entry>The number of buffers requested or granted.</entry>
+	  </row>
+	  <row>
+	    <entry>&v4l2-memory;</entry>
+	    <entry><structfield>memory</structfield></entry>
+	    <entry>Applications set this field to
+<constant>V4L2_MEMORY_MMAP</constant> or
+<constant>V4L2_MEMORY_USERPTR</constant>.</entry>
+	  </row>
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>size</structfield></entry>
+	    <entry>Explicit size of buffers, being created.</entry>
+	  </row>
+	  <row>
+	    <entry>&v4l2-format;</entry>
+	    <entry><structfield>format</structfield></entry>
+	    <entry>Application has to set the <structfield>type</structfield>
+field, other fields should be used, if the application wants to allocate buffers
+for a specific frame format.</entry>
+	  </row>
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>reserved</structfield>[8]</entry>
+	    <entry>A place holder for future extensions.</entry>
+	  </row>
+	</tbody>
+      </tgroup>
+    </table>
+  </refsect1>
+
+  <refsect1>
+    &return-value;
+
+    <variablelist>
+      <varlistentry>
+	<term><errorcode>ENOMEM</errorcode></term>
+	<listitem>
+	  <para>No memory to allocate buffers for <link linkend="mmap">memory
+mapped</link> I/O.</para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><errorcode>EINVAL</errorcode></term>
+	<listitem>
+	  <para>The buffer type (<structfield>type</structfield> field) or the
+requested I/O method (<structfield>memory</structfield>) is not
+supported.</para>
+	</listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+</refentry>
+
+<!--
+Local Variables:
+mode: sgml
+sgml-parent-document: "v4l2.sgml"
+indent-tabs-mode: nil
+End:
+-->
diff --git a/Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml b/Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml
new file mode 100644
index 0000000..509e752
--- /dev/null
+++ b/Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml
@@ -0,0 +1,96 @@
+<refentry id="vidioc-prepare-buf">
+  <refmeta>
+    <refentrytitle>ioctl VIDIOC_PREPARE_BUF</refentrytitle>
+    &manvol;
+  </refmeta>
+
+  <refnamediv>
+    <refname>VIDIOC_PREPARE_BUF</refname>
+    <refpurpose>Prepare a buffer for I/O</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_buffer *<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_PREPARE_BUF</para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><parameter>argp</parameter></term>
+	<listitem>
+	  <para></para>
+	</listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+
+  <refsect1>
+    <title>Description</title>
+
+    <para>Applications can optionally call the
+<constant>VIDIOC_PREPARE_BUF</constant> ioctl to pass ownership of the buffer
+to the driver before actually enqueuing it, using the
+<constant>VIDIOC_QBUF</constant> ioctl, and to prepare it for future I/O.
+Such preparations may include cache invalidation or cleaning. Performing them
+in advance saves time during the actual I/O. In case such cache operations are
+not required, the application can use one of
+<constant>V4L2_BUF_FLAG_NO_CACHE_INVALIDATE</constant> and
+<constant>V4L2_BUF_FLAG_NO_CACHE_CLEAN</constant> flags to skip the respective
+step.</para>
+
+    <para>The <structname>v4l2_buffer</structname> structure is
+specified in <xref linkend="buffer" />.</para>
+  </refsect1>
+
+  <refsect1>
+    &return-value;
+
+    <variablelist>
+      <varlistentry>
+	<term><errorcode>EBUSY</errorcode></term>
+	<listitem>
+	  <para>File I/O is in progress.</para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><errorcode>EINVAL</errorcode></term>
+	<listitem>
+	  <para>The buffer <structfield>type</structfield> is not
+supported, or the <structfield>index</structfield> is out of bounds,
+or no buffers have been allocated yet, or the
+<structfield>userptr</structfield> or
+<structfield>length</structfield> are invalid.</para>
+	</listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+</refentry>
+
+<!--
+Local Variables:
+mode: sgml
+sgml-parent-document: "v4l2.sgml"
+indent-tabs-mode: nil
+End:
+-->
diff --git a/drivers/media/video/v4l2-compat-ioctl32.c b/drivers/media/video/v4l2-compat-ioctl32.c
index 61979b7..4105f69 100644
--- a/drivers/media/video/v4l2-compat-ioctl32.c
+++ b/drivers/media/video/v4l2-compat-ioctl32.c
@@ -159,11 +159,16 @@ struct v4l2_format32 {
 	} fmt;
 };
 
-static int get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
+struct v4l2_create_buffers32 {
+	__u32			index;		/* output: buffers index...index + count - 1 have been created */
+	__u32			count;
+	enum v4l2_memory        memory;
+	__u32			size;		/* Explicit size, e.g., for compressed streams */
+	struct v4l2_format32	format;		/* "type" is used always, the rest if size == 0 */
+};
+
+static int __get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
 {
-	if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_format32)) ||
-			get_user(kp->type, &up->type))
-			return -EFAULT;
 	switch (kp->type) {
 	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
 	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
@@ -192,11 +197,24 @@ static int get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user
 	}
 }
 
-static int put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
+static int get_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
+{
+	if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_format32)) ||
+			get_user(kp->type, &up->type))
+			return -EFAULT;
+	return __get_v4l2_format32(kp, up);
+}
+
+static int get_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up)
+{
+	if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_create_buffers32)) ||
+	    copy_from_user(kp, up, offsetof(struct v4l2_create_buffers32, format.fmt)))
+			return -EFAULT;
+	return __get_v4l2_format32(&kp->format, &up->format);
+}
+
+static int __put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
 {
-	if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_format32)) ||
-		put_user(kp->type, &up->type))
-		return -EFAULT;
 	switch (kp->type) {
 	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
 	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
@@ -225,6 +243,22 @@ static int put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user
 	}
 }
 
+static int put_v4l2_format32(struct v4l2_format *kp, struct v4l2_format32 __user *up)
+{
+	if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_format32)) ||
+		put_user(kp->type, &up->type))
+		return -EFAULT;
+	return __put_v4l2_format32(kp, up);
+}
+
+static int put_v4l2_create32(struct v4l2_create_buffers *kp, struct v4l2_create_buffers32 __user *up)
+{
+	if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_create_buffers32)) ||
+	    copy_to_user(up, kp, offsetof(struct v4l2_create_buffers32, format.fmt)))
+			return -EFAULT;
+	return __put_v4l2_format32(&kp->format, &up->format);
+}
+
 struct v4l2_standard32 {
 	__u32		     index;
 	__u32		     id[2]; /* __u64 would get the alignment wrong */
@@ -702,6 +736,8 @@ static int put_v4l2_event32(struct v4l2_event *kp, struct v4l2_event32 __user *u
 #define VIDIOC_S_EXT_CTRLS32    _IOWR('V', 72, struct v4l2_ext_controls32)
 #define VIDIOC_TRY_EXT_CTRLS32  _IOWR('V', 73, struct v4l2_ext_controls32)
 #define	VIDIOC_DQEVENT32	_IOR ('V', 89, struct v4l2_event32)
+#define VIDIOC_CREATE_BUFS32	_IOWR('V', 92, struct v4l2_create_buffers32)
+#define VIDIOC_PREPARE_BUF32	_IOWR('V', 93, struct v4l2_buffer32)
 
 #define VIDIOC_OVERLAY32	_IOW ('V', 14, s32)
 #define VIDIOC_STREAMON32	_IOW ('V', 18, s32)
@@ -721,6 +757,7 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
 		struct v4l2_standard v2s;
 		struct v4l2_ext_controls v2ecs;
 		struct v4l2_event v2ev;
+		struct v4l2_create_buffers v2crt;
 		unsigned long vx;
 		int vi;
 	} karg;
@@ -751,6 +788,8 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
 	case VIDIOC_S_INPUT32: cmd = VIDIOC_S_INPUT; break;
 	case VIDIOC_G_OUTPUT32: cmd = VIDIOC_G_OUTPUT; break;
 	case VIDIOC_S_OUTPUT32: cmd = VIDIOC_S_OUTPUT; break;
+	case VIDIOC_CREATE_BUFS32: cmd = VIDIOC_CREATE_BUFS; break;
+	case VIDIOC_PREPARE_BUF32: cmd = VIDIOC_PREPARE_BUF; break;
 	}
 
 	switch (cmd) {
@@ -775,6 +814,12 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
 		compatible_arg = 0;
 		break;
 
+	case VIDIOC_CREATE_BUFS:
+		err = get_v4l2_create32(&karg.v2crt, up);
+		compatible_arg = 0;
+		break;
+
+	case VIDIOC_PREPARE_BUF:
 	case VIDIOC_QUERYBUF:
 	case VIDIOC_QBUF:
 	case VIDIOC_DQBUF:
@@ -860,6 +905,11 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
 		err = put_v4l2_format32(&karg.v2f, up);
 		break;
 
+	case VIDIOC_CREATE_BUFS:
+		err = put_v4l2_create32(&karg.v2crt, up);
+		break;
+
+	case VIDIOC_PREPARE_BUF:
 	case VIDIOC_QUERYBUF:
 	case VIDIOC_QBUF:
 	case VIDIOC_DQBUF:
@@ -959,6 +1009,8 @@ long v4l2_compat_ioctl32(struct file *file, unsigned int cmd, unsigned long arg)
 	case VIDIOC_DQEVENT32:
 	case VIDIOC_SUBSCRIBE_EVENT:
 	case VIDIOC_UNSUBSCRIBE_EVENT:
+	case VIDIOC_CREATE_BUFS32:
+	case VIDIOC_PREPARE_BUF32:
 		ret = do_video_ioctl(file, cmd, arg);
 		break;
 
diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c
index 002ce13..7824152 100644
--- a/drivers/media/video/v4l2-ioctl.c
+++ b/drivers/media/video/v4l2-ioctl.c
@@ -260,6 +260,8 @@ static const char *v4l2_ioctls[] = {
 	[_IOC_NR(VIDIOC_DQEVENT)]	   = "VIDIOC_DQEVENT",
 	[_IOC_NR(VIDIOC_SUBSCRIBE_EVENT)]  = "VIDIOC_SUBSCRIBE_EVENT",
 	[_IOC_NR(VIDIOC_UNSUBSCRIBE_EVENT)] = "VIDIOC_UNSUBSCRIBE_EVENT",
+	[_IOC_NR(VIDIOC_CREATE_BUFS)]      = "VIDIOC_CREATE_BUFS",
+	[_IOC_NR(VIDIOC_PREPARE_BUF)]      = "VIDIOC_PREPARE_BUF",
 };
 #define V4L2_IOCTLS ARRAY_SIZE(v4l2_ioctls)
 
@@ -2216,6 +2218,36 @@ static long __video_do_ioctl(struct file *file,
 		dbgarg(cmd, "type=0x%8.8x", sub->type);
 		break;
 	}
+	case VIDIOC_CREATE_BUFS:
+	{
+		struct v4l2_create_buffers *create = arg;
+
+		if (!ops->vidioc_create_bufs)
+			break;
+		ret = check_fmt(ops, create->format.type);
+		if (ret)
+			break;
+
+		if (create->size)
+			CLEAR_AFTER_FIELD(create, count);
+
+		ret = ops->vidioc_create_bufs(file, fh, create);
+
+		dbgarg(cmd, "count=%d\n", create->count);
+		break;
+	}
+	case VIDIOC_PREPARE_BUF:
+	{
+		struct v4l2_buffer *b = arg;
+
+		if (!ops->vidioc_prepare_buf)
+			break;
+
+		ret = ops->vidioc_prepare_buf(file, fh, b);
+
+		dbgarg(cmd, "index=%d", b->index);
+		break;
+	}
 	default:
 	{
 		bool valid_prio = true;
diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index fca24cc..0b594c7 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -653,6 +653,9 @@ struct v4l2_buffer {
 #define V4L2_BUF_FLAG_ERROR	0x0040
 #define V4L2_BUF_FLAG_TIMECODE	0x0100	/* timecode field is valid */
 #define V4L2_BUF_FLAG_INPUT     0x0200  /* input field is valid */
+/* Cache handling flags */
+#define V4L2_BUF_FLAG_NO_CACHE_INVALIDATE	0x0400
+#define V4L2_BUF_FLAG_NO_CACHE_CLEAN		0x0800
 
 /*
  *	O V E R L A Y   P R E V I E W
@@ -2092,6 +2095,16 @@ struct v4l2_dbg_chip_ident {
 	__u32 revision;    /* chip revision, chip specific */
 } __attribute__ ((packed));
 
+/* VIDIOC_CREATE_BUFS */
+struct v4l2_create_buffers {
+	__u32			index;		/* output: buffers index...index + count - 1 have been created */
+	__u32			count;
+	enum v4l2_memory        memory;
+	__u32			size;		/* Explicit size, e.g., for compressed streams */
+	struct v4l2_format	format;		/* "type" is used always, the rest if size == 0 */
+	__u32			reserved[8];
+};
+
 /*
  *	I O C T L   C O D E S   F O R   V I D E O   D E V I C E S
  *
@@ -2182,6 +2195,9 @@ struct v4l2_dbg_chip_ident {
 #define	VIDIOC_SUBSCRIBE_EVENT	 _IOW('V', 90, struct v4l2_event_subscription)
 #define	VIDIOC_UNSUBSCRIBE_EVENT _IOW('V', 91, struct v4l2_event_subscription)
 
+#define VIDIOC_CREATE_BUFS	_IOWR('V', 92, struct v4l2_create_buffers)
+#define VIDIOC_PREPARE_BUF	 _IOW('V', 93, struct v4l2_buffer)
+
 /* Reminder: when adding new ioctls please add support for them to
    drivers/media/video/v4l2-compat-ioctl32.c as well! */
 
diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
index dd9f1e7..4d1c74a 100644
--- a/include/media/v4l2-ioctl.h
+++ b/include/media/v4l2-ioctl.h
@@ -122,6 +122,8 @@ struct v4l2_ioctl_ops {
 	int (*vidioc_qbuf)    (struct file *file, void *fh, struct v4l2_buffer *b);
 	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);
+	int (*vidioc_prepare_buf)(struct file *file, void *fh, struct v4l2_buffer *b);
 
 	int (*vidioc_overlay) (struct file *file, void *fh, unsigned int i);
 	int (*vidioc_g_fbuf)   (struct file *file, void *fh,
-- 
1.7.2.5