Hi Laurent, Please see my little comment below.. On 2011-01-27 13:30, Laurent Pinchart wrote: > Create the following two ioctls and implement them at the media device > level to enumerate entities, pads and links. > > - MEDIA_IOC_ENUM_ENTITIES: Enumerate entities and their properties > - MEDIA_IOC_ENUM_LINKS: Enumerate all pads and links for a given entity > > Entity IDs can be non-contiguous. Userspace applications should > enumerate entities using the MEDIA_ENT_ID_FLAG_NEXT flag. When the flag > is set in the entity ID, the MEDIA_IOC_ENUM_ENTITIES will return the > next entity with an ID bigger than the requested one. > > Only forward links that originate at one of the entity's source pads are > returned during the enumeration process. > > Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxxxxxxxxxxxxx> > --- > Documentation/DocBook/media-entities.tmpl | 8 + > Documentation/DocBook/v4l/media-controller.xml | 2 + > .../DocBook/v4l/media-ioc-device-info.xml | 3 +- > .../DocBook/v4l/media-ioc-enum-entities.xml | 308 ++++++++++++++++++++ > Documentation/DocBook/v4l/media-ioc-enum-links.xml | 202 +++++++++++++ > drivers/media/media-device.c | 123 ++++++++ > include/linux/media.h | 85 ++++++ > include/media/media-entity.h | 24 +-- > 8 files changed, 731 insertions(+), 24 deletions(-) > create mode 100644 Documentation/DocBook/v4l/media-ioc-enum-entities.xml > create mode 100644 Documentation/DocBook/v4l/media-ioc-enum-links.xml > ... > diff --git a/Documentation/DocBook/v4l/media-ioc-enum-links.xml b/Documentation/DocBook/v4l/media-ioc-enum-links.xml > new file mode 100644 > index 0000000..daf0360 > --- /dev/null > +++ b/Documentation/DocBook/v4l/media-ioc-enum-links.xml > @@ -0,0 +1,202 @@ > +<refentry id="media-ioc-enum-links"> > + <refmeta> > + <refentrytitle>ioctl MEDIA_IOC_ENUM_LINKS</refentrytitle> > + &manvol; > + </refmeta> > + > + <refnamediv> > + <refname>MEDIA_IOC_ENUM_LINKS</refname> > + <refpurpose>Enumerate all pads and links for a given entity</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 media_links_enum *<parameter>argp</parameter></paramdef> > + </funcprototype> > + </funcsynopsis> > + </refsynopsisdiv> > + > + <refsect1> > + <title>Arguments</title> > + > + <variablelist> > + <varlistentry> > + <term><parameter>fd</parameter></term> > + <listitem> > + <para>File descriptor returned by > + <link linkend='media-func-open'><function>open()</function></link>.</para> > + </listitem> > + </varlistentry> > + <varlistentry> > + <term><parameter>request</parameter></term> > + <listitem> > + <para>MEDIA_IOC_ENUM_LINKS</para> > + </listitem> > + </varlistentry> > + <varlistentry> > + <term><parameter>argp</parameter></term> > + <listitem> > + <para></para> > + </listitem> > + </varlistentry> > + </variablelist> > + </refsect1> > + > + <refsect1> > + <title>Description</title> > + > + <para>To enumerate pads and/or links for a given entity, applications set > + the entity field of a &media-links-enum; structure and initialize the > + &media-pad-desc; and &media-link-desc; structure arrays pointed by the > + <structfield>pads</structfield> and <structfield>links</structfield> fields. > + They then call the MEDIA_IOC_ENUM_LINKS ioctl with a pointer to this > + structure.</para> > + <para>If the <structfield>pads</structfield> field is not NULL, the driver > + fills the <structfield>pads</structfield> array with information about the > + entity's pads. The array must have enough room to store all the entity's > + pads. The number of pads can be retrieved with the &MEDIA-IOC-ENUM-ENTITIES; > + ioctl.</para> > + <para>If the <structfield>links</structfield> field is not NULL, the driver > + fills the <structfield>links</structfield> array with information about the > + entity's outbound links. The array must have enough room to store all the > + entity's outbound links. The number of outbound links can be retrieved with > + the &MEDIA-IOC-ENUM-ENTITIES; ioctl.</para> > + <para>Only forward links that originate at one of the entity's source pads > + are returned during the enumeration process.</para> > + > + <table pgwide="1" frame="none" id="media-links-enum"> > + <title>struct <structname>media_links_enum</structname></title> > + <tgroup cols="3"> > + &cs-str; > + <tbody valign="top"> > + <row> > + <entry>__u32</entry> > + <entry><structfield>entity</structfield></entry> > + <entry>Entity id, set by the application.</entry> > + </row> > + <row> > + <entry>struct &media-pad-desc;</entry> > + <entry>*<structfield>pads</structfield></entry> > + <entry>Pointer to a pads array allocated by the application. Ignored > + if NULL.</entry> > + </row> > + <row> > + <entry>struct &media-link-desc;</entry> > + <entry>*<structfield>links</structfield></entry> > + <entry>Pointer to a links array allocated by the application. Ignored > + if NULL.</entry> > + </row> > + </tbody> > + </tgroup> > + </table> > + > + <table pgwide="1" frame="none" id="media-pad-desc"> > + <title>struct <structname>media_pad_desc</structname></title> > + <tgroup cols="3"> > + &cs-str; > + <tbody valign="top"> > + <row> > + <entry>__u32</entry> > + <entry><structfield>entity</structfield></entry> > + <entry>ID of the entity this pad belongs to.</entry> > + </row> > + <row> > + <entry>__u16</entry> > + <entry><structfield>index</structfield></entry> > + <entry>0-based pad index.</entry> > + </row> > + <row> > + <entry>__u32</entry> > + <entry><structfield>flags</structfield></entry> > + <entry>Pad flags, see <xref linkend="media-pad-flag" /> for more details.</entry> > + </row> > + </tbody> > + </tgroup> > + </table> > + > + <table frame="none" pgwide="1" id="media-pad-flag"> > + <title>Media pad flags</title> > + <tgroup cols="2"> > + <colspec colname="c1"/> > + <colspec colname="c2"/> > + <tbody valign="top"> > + <row> > + <entry><constant>MEDIA_PAD_FL_INPUT</constant></entry> > + <entry>Input pad, relative to the entity. Input pads sink data and > + are targets of links.</entry> > + </row> > + <row> > + <entry><constant>MEDIA_PAD_FL_OUTPUT</constant></entry> > + <entry>Output pad, relative to the entity. Output pads source data > + and are origins of links.</entry> > + </row> > + </tbody> > + </tgroup> > + </table> > + > + <table pgwide="1" frame="none" id="media-link-desc"> > + <title>struct <structname>media_links_enum</structname></title> ..the above line should perhaps be: > + <title>struct <structname>media_links_desc</structname></title> as "struct media_links_desc" is described above. BTW, I was wondering how one makes use of the pads associated with a media entity of type other than MEDIA_ENT_T_V4L2_SUBDEV*, e.g. V4L2 device - MEDIA_ENT_T_DEVNODE_V4L. I guess new standard ioctls should be added for per pads operations at V4L2 device, similarly is it is done with v4l2-subdevs. Is this right? Regards, Sylwester -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
