diff options
| -rw-r--r-- | Documentation/DocBook/media/v4l/compat.xml | 3 | ||||
| -rw-r--r-- | Documentation/DocBook/media/v4l/io.xml | 27 | ||||
| -rw-r--r-- | Documentation/DocBook/media/v4l/v4l2.xml | 2 | ||||
| -rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-create-bufs.xml | 139 | ||||
| -rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml | 88 |
5 files changed, 259 insertions, 0 deletions
diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml index 91410b6e7e08..b68698f96e7f 100644 --- a/Documentation/DocBook/media/v4l/compat.xml +++ b/Documentation/DocBook/media/v4l/compat.xml @@ -2486,6 +2486,9 @@ ioctls.</para> <listitem> <para>Flash API. <xref linkend="flash-controls" /></para> </listitem> + <listitem> + <para>&VIDIOC-CREATE-BUFS; and &VIDIOC-PREPARE-BUF; ioctls.</para> + </listitem> </itemizedlist> </section> diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml index c57d1ec6291c..3f47df1aa54a 100644 --- a/Documentation/DocBook/media/v4l/io.xml +++ b/Documentation/DocBook/media/v4l/io.xml @@ -927,6 +927,33 @@ 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_PREPARED</constant></entry> + <entry>0x0400</entry> + <entry>The buffer has been prepared for I/O and can be queued by the +application. Drivers set or clear this flag when the +<link linkend="vidioc-querybuf">VIDIOC_QUERYBUF</link>, <link + linkend="vidioc-qbuf">VIDIOC_PREPARE_BUF</link>, <link + linkend="vidioc-qbuf">VIDIOC_QBUF</link> or <link + linkend="vidioc-qbuf">VIDIOC_DQBUF</link> ioctl is called.</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 be 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 40132c277647..2ab365c10fb9 100644 --- a/Documentation/DocBook/media/v4l/v4l2.xml +++ b/Documentation/DocBook/media/v4l/v4l2.xml @@ -469,6 +469,7 @@ 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; @@ -511,6 +512,7 @@ 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 000000000000..73ae8a6cd004 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml @@ -0,0 +1,139 @@ +<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 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 +<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. The +<structfield>format</structfield> field shall typically be filled in using +either the <constant>VIDIOC_TRY_FMT</constant> or +<constant>VIDIOC_G_FMT</constant> ioctl(). Additionally, applications can adjust +<structfield>sizeimage</structfield> fields to fit their specific needs. The +<structfield>reserved</structfield> array must be zeroed.</para> + + <para>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. On return <structfield>count</structfield> can be smaller than +the number requested. The driver may also increase buffer sizes if required, +however, it will not update <structfield>sizeimage</structfield> field values. +The user has to use <constant>VIDIOC_QUERYBUF</constant> to retrieve that +information.</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>&v4l2-format;</entry> + <entry><structfield>format</structfield></entry> + <entry>Filled in by the application, preserved by the driver.</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> 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 000000000000..7bde698760e4 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-prepare-buf.xml @@ -0,0 +1,88 @@ +<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> |