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 <[email protected]> --- v4: 1. CREATE_BUFS now takes an array of plane sizes and a fourcc code in its argument, instead of a frame format specification, including documentation update 2. documentation improvements, as suggested by Hans 3. increased reserved fields to 18, as suggested by Sakari Documentation/DocBook/media/v4l/io.xml | 17 ++ Documentation/DocBook/media/v4l/v4l2.xml | 2 + .../DocBook/media/v4l/vidioc-create-bufs.xml | 161 ++++++++++++++++++++ .../DocBook/media/v4l/vidioc-prepare-buf.xml | 96 ++++++++++++ drivers/media/video/v4l2-compat-ioctl32.c | 6 + drivers/media/video/v4l2-ioctl.c | 26 +++ include/linux/videodev2.h | 18 +++ include/media/v4l2-ioctl.h | 2 + 8 files changed, 328 insertions(+), 0 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..ff03dd2 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 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 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..b37b9a4 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml @@ -0,0 +1,161 @@ +<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 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. If <structfield>num_planes</structfield> == 0 or all elements of the +<structfield>sizes</structfield> array are 0, then buffers, suitable for the +currently configured video format, are allocated, exactly like for the +<constant>VIDIOC_REQBUFS</constant> ioctl. If +<structfield>num_planes</structfield> > 0 and at least some of the respective +<structfield>sizes</structfield> elements are non-zero, this information will be +used for buffer-allocation. 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. On return <structfield>count</structfield> can be smaller +than the number requested.</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>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry>V4L2 buffer type: one of <constant>V4L2_BUF_TYPE_*</constant> +values.</entry> + </row> + <row> + <entry>__u32</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>fourcc</structfield></entry> + <entry>One of V4L2_PIX_FMT_* FOURCCs of the video data.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>num_planes</structfield></entry> + <entry>Number of planes or 0 to use the current format.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>size[VIDEO_MAX_PLANES]</structfield></entry> + <entry>Explicit sizes of buffers, being created.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[18]</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..ee5eec8 100644 --- a/drivers/media/video/v4l2-compat-ioctl32.c +++ b/drivers/media/video/v4l2-compat-ioctl32.c @@ -702,6 +702,7 @@ 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_PREPARE_BUF32 _IOWR('V', 93, struct v4l2_buffer32) #define VIDIOC_OVERLAY32 _IOW ('V', 14, s32) #define VIDIOC_STREAMON32 _IOW ('V', 18, s32) @@ -751,6 +752,7 @@ 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_PREPARE_BUF32: cmd = VIDIOC_PREPARE_BUF; break; } switch (cmd) { @@ -775,6 +777,7 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar compatible_arg = 0; break; + case VIDIOC_PREPARE_BUF: case VIDIOC_QUERYBUF: case VIDIOC_QBUF: case VIDIOC_DQBUF: @@ -860,6 +863,7 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar err = put_v4l2_format32(&karg.v2f, up); break; + case VIDIOC_PREPARE_BUF: case VIDIOC_QUERYBUF: case VIDIOC_QBUF: case VIDIOC_DQBUF: @@ -959,6 +963,8 @@ 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_BUFS: + 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..3da87c0 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 +2218,30 @@ 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 = ops->vidioc_create_bufs(file, fh, create); + + dbgarg(cmd, "count=%u @ %u\n", create->count, create->index); + 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..3cd0cb3 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 +2095,18 @@ 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; + __u32 type; + __u32 memory; + __u32 fourcc; + __u32 num_planes; + __u32 sizes[VIDEO_MAX_PLANES]; + __u32 reserved[18]; +}; + /* * 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 +2197,9 @@ 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 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
