On Wed, 20 Jul 2011, Sakari Ailus wrote:
> Hi, Guennadi!
>
> Thanks for the patch!
>
> On Wed, Jul 20, 2011 at 10:43:08AM +0200, Guennadi Liakhovetski wrote:
> > 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@xxxxxx>
> > ---
> >
> > 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>
>
> No need to mention -ENOMEM here. It's already in the return values below;
> the same goes for the EINVAL just below.
Yes, incremental patches welcome.
>
> > + <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>
>
> I'm not sure if we want to use struct v4l2_buffer here. It's an obvious
> choice, but there's an issue in using it.
>
> The struct is almost full i.e. there are very few reserved fields in it,
> namely two, counting the input field which was unused AFAIR. There are now
> three ioctls using it as their argument.
>
> Future functionality which would be nice:
>
> - Format counters. Every format set by S_FMT (or gotten by G_FMT) should
> come with a counter value so that the user would know the format of
> dequeued buffers when setting the format on-the-fly. Currently there are
> only bytesperline and length, but the format can't be explicitly
> determined from those.
>
> - Binding to generic DMA buffers. This can likely be achieved by using the m
> union in struct v4l2_buffer. (Speaking of which: these buffers likely have
> a cache behaviour defined for them, e.g. they might be non-cacheable. This
> probably has no effect on the cache flags in V4L2 but it might still be
> good to keep this in mind.)
>
> I don't have an obvious replacement for it either. There are two options I
> can see: Create a new struct v4l2_ext_buffer which contains the old
> v4l2_buffer plus a bunch of reserved fields, or use the two last fields to
> hold a pointer to an extension struct, v4l2_buffer_ext. The new structure
> would later be used to contain the reserved fields.
>
> I admit that this is not an issue right now, myt point is that I don't want
> this to be an issue in the future either.
Good, then we'll address it, when it becomes an issue.
>
> > + </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;
>
> Aren't enums something to avoid in public APIs? -> __u32?
They are, but this specific enum is already used in "struct
v4l2_requestbuffers" and "struct v4l2_buffer" so, I decided, it would be
consistent to use it here too, even if it involves extra compat craft, and
the embedded struct v4l2_format also includes an enum in it anyway, so,
basically, they are all over the place.
>
> > + __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
> >
>
> Regards,
So, I take it as an ack;-)
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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