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Commit 140d8816 authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Mauro Carvalho Chehab
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[media] media: Media device information query 

Create the following ioctl and implement it at the media device level to
query device information.

- MEDIA_IOC_DEVICE_INFO: Query media device information

The ioctl and its data structure are defined in the new kernel header
linux/media.h available to userspace applications.
Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: default avatarHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 503c3d82
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Documentation/DocBook/media-entities.tmpl
View file @ 140d8816
......@@ -11,6 +11,10 @@
<!ENTITY func-select "<link linkend='func-select'><function>select()</function></link>">
<!ENTITY func-write "<link linkend='func-write'><function>write()</function></link>">
<!ENTITY media-func-close "<link linkend='media-func-close'><function>close()</function></link>">
<!ENTITY media-func-ioctl "<link linkend='media-func-ioctl'><function>ioctl()</function></link>">
<!ENTITY media-func-open "<link linkend='media-func-open'><function>open()</function></link>">
<!-- Ioctls -->
<!ENTITY VIDIOC-CROPCAP "<link linkend='vidioc-cropcap'><constant>VIDIOC_CROPCAP</constant></link>">
<!ENTITY VIDIOC-DBG-G-CHIP-IDENT "<link linkend='vidioc-dbg-g-chip-ident'><constant>VIDIOC_DBG_G_CHIP_IDENT</constant></link>">
......@@ -87,6 +91,8 @@
<!ENTITY VIDIOC-TRY-FMT "<link linkend='vidioc-g-fmt'><constant>VIDIOC_TRY_FMT</constant></link>">
<!ENTITY VIDIOC-UNSUBSCRIBE-EVENT "<link linkend='vidioc-subscribe-event'><constant>VIDIOC_UNSUBSCRIBE_EVENT</constant></link>">
<!ENTITY MEDIA-IOC-DEVICE-INFO "<link linkend='media-ioc-device-info'><constant>MEDIA_IOC_DEVICE_INFO</constant></link>">
<!-- Types -->
<!ENTITY v4l2-std-id "<link linkend='v4l2-std-id'>v4l2_std_id</link>">
......@@ -184,6 +190,8 @@
<!ENTITY v4l2-vbi-format "struct&nbsp;<link linkend='v4l2-vbi-format'>v4l2_vbi_format</link>">
<!ENTITY v4l2-window "struct&nbsp;<link linkend='v4l2-window'>v4l2_window</link>">
<!ENTITY media-device-info "struct&nbsp;<link linkend='media-device-info'>media_device_info</link>">
<!-- Error Codes -->
<!ENTITY EACCES "<errorcode>EACCES</errorcode> error code">
<!ENTITY EAGAIN "<errorcode>EAGAIN</errorcode> error code">
......@@ -328,6 +336,10 @@
<!ENTITY sub-media-indices SYSTEM "media-indices.tmpl">
<!ENTITY sub-media-controller SYSTEM "v4l/media-controller.xml">
<!ENTITY sub-media-open SYSTEM "v4l/media-func-open.xml">
<!ENTITY sub-media-close SYSTEM "v4l/media-func-close.xml">
<!ENTITY sub-media-ioctl SYSTEM "v4l/media-func-ioctl.xml">
<!ENTITY sub-media-ioc-device-info SYSTEM "v4l/media-ioc-device-info.xml">
<!-- Function Reference -->
<!ENTITY close SYSTEM "v4l/func-close.xml">
......
Documentation/DocBook/v4l/media-controller.xml
View file @ 140d8816
......@@ -74,3 +74,13 @@
pad to a sink pad.</para>
</section>
</chapter>
<appendix id="media-user-func">
<title>Function Reference</title>
<!-- Keep this alphabetically sorted. -->
&sub-media-open;
&sub-media-close;
&sub-media-ioctl;
<!-- All ioctls go here. -->
&sub-media-ioc-device-info;
</appendix>
Documentation/DocBook/v4l/media-func-close.xml 0 → 100644
View file @ 140d8816
<refentry id="media-func-close">
<refmeta>
<refentrytitle>media close()</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname>media-close</refname>
<refpurpose>Close a media device</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;unistd.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>close</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>fd</parameter></term>
<listitem>
<para>&fd;</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>Closes the media device. Resources associated with the file descriptor
are freed. The device configuration remain unchanged.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para><function>close</function> returns 0 on success. On error, -1 is
returned, and <varname>errno</varname> is set appropriately. Possible error
codes are:</para>
<variablelist>
<varlistentry>
<term><errorcode>EBADF</errorcode></term>
<listitem>
<para><parameter>fd</parameter> is not a valid open file descriptor.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
Documentation/DocBook/v4l/media-func-ioctl.xml 0 → 100644
View file @ 140d8816
<refentry id="media-func-ioctl">
<refmeta>
<refentrytitle>media ioctl()</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname>media-ioctl</refname>
<refpurpose>Control a media device</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;sys/ioctl.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>ioctl</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>int <parameter>request</parameter></paramdef>
<paramdef>void *<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>Media ioctl request code as defined in the media.h header file,
for example MEDIA_IOC_SETUP_LINK.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>argp</parameter></term>
<listitem>
<para>Pointer to a request-specific structure.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>The <function>ioctl()</function> function manipulates media device
parameters. The argument <parameter>fd</parameter> must be an open file
descriptor.</para>
<para>The ioctl <parameter>request</parameter> code specifies the media
function to be called. It has encoded in it whether the argument is an
input, output or read/write parameter, and the size of the argument
<parameter>argp</parameter> in bytes.</para>
<para>Macros and structures definitions specifying media ioctl requests and
their parameters are located in the media.h header file. All media ioctl
requests, their respective function and parameters are specified in
<xref linkend="media-user-func" />.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para><function>ioctl()</function> returns <returnvalue>0</returnvalue> on
success. On failure, <returnvalue>-1</returnvalue> is returned, and the
<varname>errno</varname> variable is set appropriately. Generic error codes
are listed below, and request-specific error codes are listed in the
individual requests descriptions.</para>
<para>When an ioctl that takes an output or read/write parameter fails,
the parameter remains unmodified.</para>
<variablelist>
<varlistentry>
<term><errorcode>EBADF</errorcode></term>
<listitem>
<para><parameter>fd</parameter> is not a valid open file descriptor.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>EFAULT</errorcode></term>
<listitem>
<para><parameter>argp</parameter> references an inaccessible memory
area.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>EINVAL</errorcode></term>
<listitem>
<para>The <parameter>request</parameter> or the data pointed to by
<parameter>argp</parameter> is not valid. This is a very common error
code, see the individual ioctl requests listed in
<xref linkend="media-user-func" /> for actual causes.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>ENOMEM</errorcode></term>
<listitem>
<para>Insufficient kernel memory was available to complete the
request.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>ENOTTY</errorcode></term>
<listitem>
<para><parameter>fd</parameter> is not associated with a character
special device.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
Documentation/DocBook/v4l/media-func-open.xml 0 → 100644
View file @ 140d8816
<refentry id="media-func-open">
<refmeta>
<refentrytitle>media open()</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname>media-open</refname>
<refpurpose>Open a media device</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;fcntl.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>open</function></funcdef>
<paramdef>const char *<parameter>device_name</parameter></paramdef>
<paramdef>int <parameter>flags</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>device_name</parameter></term>
<listitem>
<para>Device to be opened.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>flags</parameter></term>
<listitem>
<para>Open flags. Access mode must be either <constant>O_RDONLY</constant>
or <constant>O_RDWR</constant>. Other flags have no effect.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>To open a media device applications call <function>open()</function>
with the desired device name. The function has no side effects; the device
configuration remain unchanged.</para>
<para>When the device is opened in read-only mode, attemps to modify its
configuration will result in an error, and <varname>errno</varname> will be
set to <errorcode>EBADF</errorcode>.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para><function>open</function> returns the new file descriptor on success.
On error, -1 is returned, and <varname>errno</varname> is set appropriately.
Possible error codes are:</para>
<variablelist>
<varlistentry>
<term><errorcode>EACCES</errorcode></term>
<listitem>
<para>The requested access to the file is not allowed.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>EMFILE</errorcode></term>
<listitem>
<para>The process already has the maximum number of files open.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>ENFILE</errorcode></term>
<listitem>
<para>The system limit on the total number of open files has been
reached.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>ENOMEM</errorcode></term>
<listitem>
<para>Insufficient kernel memory was available.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>ENXIO</errorcode></term>
<listitem>
<para>No device corresponding to this device special file exists.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
Documentation/DocBook/v4l/media-ioc-device-info.xml 0 → 100644
View file @ 140d8816
<refentry id="media-ioc-device-info">
<refmeta>
<refentrytitle>ioctl MEDIA_IOC_DEVICE_INFO</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname>MEDIA_IOC_DEVICE_INFO</refname>
<refpurpose>Query device information</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_device_info *<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>MEDIA_IOC_DEVICE_INFO</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>argp</parameter></term>
<listitem>
<para></para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>All media devices must support the <constant>MEDIA_IOC_DEVICE_INFO</constant>
ioctl. To query device information, applications call the ioctl with a
pointer to a &media-device-info;. The driver fills the structure and returns
the information to the application.
The ioctl never fails.</para>
<table pgwide="1" frame="none" id="media-device-info">
<title>struct <structname>media_device_info</structname></title>
<tgroup cols="3">
&cs-str;
<tbody valign="top">
<row>
<entry>char</entry>
<entry><structfield>driver</structfield>[16]</entry>
<entry><para>Name of the driver implementing the media API as a
NUL-terminated ASCII string. The driver version is stored in the
<structfield>driver_version</structfield> field.</para>
<para>Driver specific applications can use this information to
verify the driver identity. It is also useful to work around
known bugs, or to identify drivers in error reports.</para></entry>
</row>
<row>
<entry>char</entry>
<entry><structfield>model</structfield>[32]</entry>
<entry>Device model name as a NUL-terminated UTF-8 string. The
device version is stored in the <structfield>device_version</structfield>
field and is not be appended to the model name.</entry>
</row>
<row>
<entry>char</entry>
<entry><structfield>serial</structfield>[40]</entry>
<entry>Serial number as a NUL-terminated ASCII string.</entry>
</row>
<row>
<entry>char</entry>
<entry><structfield>bus_info</structfield>[32]</entry>
<entry>Location of the device in the system as a NUL-terminated
ASCII string. This includes the bus type name (PCI, USB, ...) and a
bus-specific identifier.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>media_version</structfield></entry>
<entry>Media API version, formatted with the
<constant>KERNEL_VERSION()</constant> macro.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>hw_revision</structfield></entry>
<entry>Hardware device revision in a driver-specific format.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>media_version</structfield></entry>
<entry>Media device driver version, formatted with the
<constant>KERNEL_VERSION()</constant> macro. Together with the
<structfield>driver</structfield> field this identifies a particular
driver.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>reserved</structfield>[31]</entry>
<entry>Reserved for future extensions. Drivers and applications must
set this array to zero.</entry>
</row>
</tbody>
</tgroup>
</table>
<para>The <structfield>serial</structfield> and <structfield>bus_info</structfield>
fields can be used to distinguish between multiple instances of otherwise
identical hardware. The serial number takes precedence when provided and can
be assumed to be unique. If the serial number is an empty string, the
<structfield>bus_info</structfield> field can be used instead. The
<structfield>bus_info</structfield> field is guaranteed to be unique, but
can vary across reboots or device unplug/replug.</para>
</refsect1>
<refsect1>
<title>Return value</title>
<para>This function doesn't return specific error codes.</para>
</refsect1>
</refentry>
drivers/media/media-device.c
View file @ 140d8816
......@@ -22,13 +22,70 @@
#include <linux/types.h>
#include <linux/ioctl.h>
#include <linux/media.h>
#include <media/media-device.h>
#include <media/media-devnode.h>
#include <media/media-entity.h>
/* -----------------------------------------------------------------------------
* Userspace API
*/
static int media_device_open(struct file *filp)
{
return 0;
}
static int media_device_close(struct file *filp)
{
return 0;
}
static int media_device_get_info(struct media_device *dev,
struct media_device_info __user *__info)
{
struct media_device_info info;
memset(&info, 0, sizeof(info));
strlcpy(info.driver, dev->dev->driver->name, sizeof(info.driver));
strlcpy(info.model, dev->model, sizeof(info.model));
strlcpy(info.serial, dev->serial, sizeof(info.serial));
strlcpy(info.bus_info, dev->bus_info, sizeof(info.bus_info));
info.media_version = MEDIA_API_VERSION;
info.hw_revision = dev->hw_revision;
info.driver_version = dev->driver_version;
return copy_to_user(__info, &info, sizeof(*__info));
}
static long media_device_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
{
struct media_devnode *devnode = media_devnode_data(filp);
struct media_device *dev = to_media_device(devnode);
long ret;
switch (cmd) {
case MEDIA_IOC_DEVICE_INFO:
ret = media_device_get_info(dev,
(struct media_device_info __user *)arg);
break;
default:
ret = -ENOIOCTLCMD;
}
return ret;
}
static const struct media_file_operations media_device_fops = {
.owner = THIS_MODULE,
.open = media_device_open,
.ioctl = media_device_ioctl,
.release = media_device_close,
};
/* -----------------------------------------------------------------------------
......
include/linux/Kbuild
View file @ 140d8816
......@@ -233,6 +233,7 @@ header-y += magic.h
header-y += major.h
header-y += map_to_7segment.h
header-y += matroxfb.h
header-y += media.h
header-y += mempolicy.h
header-y += meye.h
header-y += mii.h
......
include/linux/media.h 0 → 100644
View file @ 140d8816
/*
* Multimedia device API
*
* Copyright (C) 2010 Nokia Corporation
*
* Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
* Sakari Ailus <sakari.ailus@iki.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef __LINUX_MEDIA_H
#define __LINUX_MEDIA_H
#include <linux/ioctl.h>
#include <linux/types.h>
#include <linux/version.h>
#define MEDIA_API_VERSION KERNEL_VERSION(0, 1, 0)
struct media_device_info {
char driver[16];
char model[32];
char serial[40];
char bus_info[32];
__u32 media_version;
__u32 hw_revision;
__u32 driver_version;
__u32 reserved[31];
};
#define MEDIA_IOC_DEVICE_INFO _IOWR('M', 1, struct media_device_info)
#endif /* __LINUX_MEDIA_H */
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