[media] DocBook: Move all media docbook stuff into its own directory

This patch addresses several issues pointed by Randy Dunlap
<rdunlap@xenotime.net> at changeset ece722c:

- In the generated index.html file, "media" is listed first, but it
  should be listed in alphabetical order, not first.

- The generated files are (hidden) in .tmpmedia/

- The link from the top-level index.html file to "media" is to
  media/index.html, but the file is actually in .tmpmedia/media/index.html

- Please build docs with and without using "O=builddir" and test that.

- Would it be possible for media to have its own Makefile instead of
  merging into this one?

Due to the way cleandocs target works, I had to rename the media DocBook
to media_api, otherwise cleandocs would remove the /media directory.

Thanks-to: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 659 insertions, 0 deletions

diff --git a/Documentation/DocBook/media/v4l/capture.c.xml b/Documentation/DocBook/media/v4l/capture.c.xml
new file mode 100644
index 000000000000..1c5c49a2de59
--- /dev/null
+++ b/Documentation/DocBook/media/v4l/capture.c.xml
@@ -0,0 +1,659 @@
+<programlisting>
+/*
+ *  V4L2 video capture example
+ *
+ *  This program can be used and distributed without restrictions.
+ *
+ *      This program is provided with the V4L2 API
+ * see http://linuxtv.org/docs.php for more information
+ */
+
+#include &lt;stdio.h&gt;
+#include &lt;stdlib.h&gt;
+#include &lt;string.h&gt;
+#include &lt;assert.h&gt;
+
+#include &lt;getopt.h&gt;             /* getopt_long() */
+
+#include &lt;fcntl.h&gt;              /* low-level i/o */
+#include &lt;unistd.h&gt;
+#include &lt;errno.h&gt;
+#include &lt;sys/stat.h&gt;
+#include &lt;sys/types.h&gt;
+#include &lt;sys/time.h&gt;
+#include &lt;sys/mman.h&gt;
+#include &lt;sys/ioctl.h&gt;
+
+#include &lt;linux/videodev2.h&gt;
+
+#define CLEAR(x) memset(&amp;(x), 0, sizeof(x))
+
+enum io_method {
+        IO_METHOD_READ,
+        IO_METHOD_MMAP,
+        IO_METHOD_USERPTR,
+};
+
+struct buffer {
+        void   *start;
+        size_t  length;
+};
+
+static char            *dev_name;
+static enum io_method   io = IO_METHOD_MMAP;
+static int              fd = -1;
+struct buffer          *buffers;
+static unsigned int     n_buffers;
+static int              out_buf;
+static int              force_format;
+static int              frame_count = 70;
+
+static void errno_exit(const char *s)
+{
+        fprintf(stderr, "%s error %d, %s\n", s, errno, strerror(errno));
+        exit(EXIT_FAILURE);
+}
+
+static int xioctl(int fh, int request, void *arg)
+{
+        int r;
+
+        do {
+                r = ioctl(fh, request, arg);
+        } while (-1 == r &amp;&amp; EINTR == errno);
+
+        return r;
+}
+
+static void process_image(const void *p, int size)
+{
+        if (out_buf)
+                fwrite(p, size, 1, stdout);
+
+        fflush(stderr);
+        fprintf(stderr, ".");
+        fflush(stdout);
+}
+
+static int read_frame(void)
+{
+        struct <link linkend="v4l2-buffer">v4l2_buffer</link> buf;
+        unsigned int i;
+
+        switch (io) {
+        case IO_METHOD_READ:
+                if (-1 == read(fd, buffers[0].start, buffers[0].length)) {
+                        switch (errno) {
+                        case EAGAIN:
+                                return 0;
+
+                        case EIO:
+                                /* Could ignore EIO, see spec. */
+
+                                /* fall through */
+
+                        default:
+                                errno_exit("read");
+                        }
+                }
+
+                process_image(buffers[0].start, buffers[0].length);
+                break;
+
+        case IO_METHOD_MMAP:
+                CLEAR(buf);
+
+                buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+                buf.memory = V4L2_MEMORY_MMAP;
+
+                if (-1 == xioctl(fd, VIDIOC_DQBUF, &amp;buf)) {
+                        switch (errno) {
+                        case EAGAIN:
+                                return 0;
+
+                        case EIO:
+                                /* Could ignore EIO, see spec. */
+
+                                /* fall through */
+
+                        default:
+                                errno_exit("VIDIOC_DQBUF");
+                        }
+                }
+
+                assert(buf.index &lt; n_buffers);
+
+                process_image(buffers[buf.index].start, buf.bytesused);
+
+                if (-1 == xioctl(fd, VIDIOC_QBUF, &amp;buf))
+                        errno_exit("VIDIOC_QBUF");
+                break;
+
+        case IO_METHOD_USERPTR:
+                CLEAR(buf);
+
+                buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+                buf.memory = V4L2_MEMORY_USERPTR;
+
+                if (-1 == xioctl(fd, VIDIOC_DQBUF, &amp;buf)) {
+                        switch (errno) {
+                        case EAGAIN:
+                                return 0;
+
+                        case EIO:
+                                /* Could ignore EIO, see spec. */
+
+                                /* fall through */
+
+                        default:
+                                errno_exit("VIDIOC_DQBUF");
+                        }
+                }
+
+                for (i = 0; i &lt; n_buffers; ++i)
+                        if (buf.m.userptr == (unsigned long)buffers[i].start
+                            &amp;&amp; buf.length == buffers[i].length)
+                                break;
+
+                assert(i &lt; n_buffers);
+
+                process_image((void *)buf.m.userptr, buf.bytesused);
+
+                if (-1 == xioctl(fd, VIDIOC_QBUF, &amp;buf))
+                        errno_exit("VIDIOC_QBUF");
+                break;
+        }
+
+        return 1;
+}
+
+static void mainloop(void)
+{
+        unsigned int count;
+
+        count = frame_count;
+
+        while (count-- &gt; 0) {
+                for (;;) {
+                        fd_set fds;
+                        struct timeval tv;
+                        int r;
+
+                        FD_ZERO(&amp;fds);
+                        FD_SET(fd, &amp;fds);
+
+                        /* Timeout. */
+                        tv.tv_sec = 2;
+                        tv.tv_usec = 0;
+
+                        r = select(fd + 1, &amp;fds, NULL, NULL, &amp;tv);
+
+                        if (-1 == r) {
+                                if (EINTR == errno)
+                                        continue;
+                                errno_exit("select");
+                        }
+
+                        if (0 == r) {
+                                fprintf(stderr, "select timeout\n");
+                                exit(EXIT_FAILURE);
+                        }
+
+                        if (read_frame())
+                                break;
+                        /* EAGAIN - continue select loop. */
+                }
+        }
+}
+
+static void stop_capturing(void)
+{
+        enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type;
+
+        switch (io) {
+        case IO_METHOD_READ:
+                /* Nothing to do. */
+                break;
+
+        case IO_METHOD_MMAP:
+        case IO_METHOD_USERPTR:
+                type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+                if (-1 == xioctl(fd, VIDIOC_STREAMOFF, &amp;type))
+                        errno_exit("VIDIOC_STREAMOFF");
+                break;
+        }
+}
+
+static void start_capturing(void)
+{
+        unsigned int i;
+        enum <link linkend="v4l2-buf-type">v4l2_buf_type</link> type;
+
+        switch (io) {
+        case IO_METHOD_READ:
+                /* Nothing to do. */
+                break;
+
+        case IO_METHOD_MMAP:
+                for (i = 0; i &lt; n_buffers; ++i) {
+                        struct <link linkend="v4l2-buffer">v4l2_buffer</link> buf;
+
+                        CLEAR(buf);
+                        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+                        buf.memory = V4L2_MEMORY_MMAP;
+                        buf.index = i;
+
+                        if (-1 == xioctl(fd, VIDIOC_QBUF, &amp;buf))
+                                errno_exit("VIDIOC_QBUF");
+                }
+                type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+                if (-1 == xioctl(fd, VIDIOC_STREAMON, &amp;type))
+                        errno_exit("VIDIOC_STREAMON");
+                break;
+
+        case IO_METHOD_USERPTR:
+                for (i = 0; i &lt; n_buffers; ++i) {
+                        struct <link linkend="v4l2-buffer">v4l2_buffer</link> buf;
+
+                        CLEAR(buf);
+                        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+                        buf.memory = V4L2_MEMORY_USERPTR;
+                        buf.index = i;
+                        buf.m.userptr = (unsigned long)buffers[i].start;
+                        buf.length = buffers[i].length;
+
+                        if (-1 == xioctl(fd, VIDIOC_QBUF, &amp;buf))
+                                errno_exit("VIDIOC_QBUF");
+                }
+                type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+                if (-1 == xioctl(fd, VIDIOC_STREAMON, &amp;type))
+                        errno_exit("VIDIOC_STREAMON");
+                break;
+        }
+}
+
+static void uninit_device(void)
+{
+        unsigned int i;
+
+        switch (io) {
+        case IO_METHOD_READ:
+                free(buffers[0].start);
+                break;
+
+        case IO_METHOD_MMAP:
+                for (i = 0; i &lt; n_buffers; ++i)
+                        if (-1 == munmap(buffers[i].start, buffers[i].length))
+                                errno_exit("munmap");
+                break;
+
+        case IO_METHOD_USERPTR:
+                for (i = 0; i &lt; n_buffers; ++i)
+                        free(buffers[i].start);
+                break;
+        }
+
+        free(buffers);
+}
+
+static void init_read(unsigned int buffer_size)
+{
+        buffers = calloc(1, sizeof(*buffers));
+
+        if (!buffers) {
+                fprintf(stderr, "Out of memory\n");
+                exit(EXIT_FAILURE);
+        }
+
+        buffers[0].length = buffer_size;
+        buffers[0].start = malloc(buffer_size);
+
+        if (!buffers[0].start) {
+                fprintf(stderr, "Out of memory\n");
+                exit(EXIT_FAILURE);
+        }
+}
+
+static void init_mmap(void)
+{
+        struct <link linkend="v4l2-requestbuffers">v4l2_requestbuffers</link> req;
+
+        CLEAR(req);
+
+        req.count = 4;
+        req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+        req.memory = V4L2_MEMORY_MMAP;
+
+        if (-1 == xioctl(fd, VIDIOC_REQBUFS, &amp;req)) {
+                if (EINVAL == errno) {
+                        fprintf(stderr, "%s does not support "
+                                 "memory mapping\n", dev_name);
+                        exit(EXIT_FAILURE);
+                } else {
+                        errno_exit("VIDIOC_REQBUFS");
+                }
+        }
+
+        if (req.count &lt; 2) {
+                fprintf(stderr, "Insufficient buffer memory on %s\n",
+                         dev_name);
+                exit(EXIT_FAILURE);
+        }
+
+        buffers = calloc(req.count, sizeof(*buffers));
+
+        if (!buffers) {
+                fprintf(stderr, "Out of memory\n");
+                exit(EXIT_FAILURE);
+        }
+
+        for (n_buffers = 0; n_buffers &lt; req.count; ++n_buffers) {
+                struct <link linkend="v4l2-buffer">v4l2_buffer</link> buf;
+
+                CLEAR(buf);
+
+                buf.type        = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+                buf.memory      = V4L2_MEMORY_MMAP;
+                buf.index       = n_buffers;
+
+                if (-1 == xioctl(fd, VIDIOC_QUERYBUF, &amp;buf))
+                        errno_exit("VIDIOC_QUERYBUF");
+
+                buffers[n_buffers].length = buf.length;
+                buffers[n_buffers].start =
+                        mmap(NULL /* start anywhere */,
+                              buf.length,
+                              PROT_READ | PROT_WRITE /* required */,
+                              MAP_SHARED /* recommended */,
+                              fd, buf.m.offset);
+
+                if (MAP_FAILED == buffers[n_buffers].start)
+                        errno_exit("mmap");
+        }
+}
+
+static void init_userp(unsigned int buffer_size)
+{
+        struct <link linkend="v4l2-requestbuffers">v4l2_requestbuffers</link> req;
+
+        CLEAR(req);
+
+        req.count  = 4;
+        req.type   = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+        req.memory = V4L2_MEMORY_USERPTR;
+
+        if (-1 == xioctl(fd, VIDIOC_REQBUFS, &amp;req)) {
+                if (EINVAL == errno) {
+                        fprintf(stderr, "%s does not support "
+                                 "user pointer i/o\n", dev_name);
+                        exit(EXIT_FAILURE);
+                } else {
+                        errno_exit("VIDIOC_REQBUFS");
+                }
+        }
+
+        buffers = calloc(4, sizeof(*buffers));
+
+        if (!buffers) {
+                fprintf(stderr, "Out of memory\n");
+                exit(EXIT_FAILURE);
+        }
+
+        for (n_buffers = 0; n_buffers &lt; 4; ++n_buffers) {
+                buffers[n_buffers].length = buffer_size;
+                buffers[n_buffers].start = malloc(buffer_size);
+
+                if (!buffers[n_buffers].start) {
+                        fprintf(stderr, "Out of memory\n");
+                        exit(EXIT_FAILURE);
+                }
+        }
+}
+
+static void init_device(void)
+{
+        struct <link linkend="v4l2-capability">v4l2_capability</link> cap;
+        struct <link linkend="v4l2-cropcap">v4l2_cropcap</link> cropcap;
+        struct <link linkend="v4l2-crop">v4l2_crop</link> crop;
+        struct <link linkend="v4l2-format">v4l2_format</link> fmt;
+        unsigned int min;
+
+        if (-1 == xioctl(fd, VIDIOC_QUERYCAP, &amp;cap)) {
+                if (EINVAL == errno) {
+                        fprintf(stderr, "%s is no V4L2 device\n",
+                                 dev_name);
+                        exit(EXIT_FAILURE);
+                } else {
+                        errno_exit("VIDIOC_QUERYCAP");
+                }
+        }
+
+        if (!(cap.capabilities &amp; V4L2_CAP_VIDEO_CAPTURE)) {
+                fprintf(stderr, "%s is no video capture device\n",
+                         dev_name);
+                exit(EXIT_FAILURE);
+        }
+
+        switch (io) {
+        case IO_METHOD_READ:
+                if (!(cap.capabilities &amp; V4L2_CAP_READWRITE)) {
+                        fprintf(stderr, "%s does not support read i/o\n",
+                                 dev_name);
+                        exit(EXIT_FAILURE);
+                }
+                break;
+
+        case IO_METHOD_MMAP:
+        case IO_METHOD_USERPTR:
+                if (!(cap.capabilities &amp; V4L2_CAP_STREAMING)) {
+                        fprintf(stderr, "%s does not support streaming i/o\n",
+                                 dev_name);
+                        exit(EXIT_FAILURE);
+                }
+                break;
+        }
+
+
+        /* Select video input, video standard and tune here. */
+
+
+        CLEAR(cropcap);
+
+        cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+
+        if (0 == xioctl(fd, VIDIOC_CROPCAP, &amp;cropcap)) {
+                crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+                crop.c = cropcap.defrect; /* reset to default */
+
+                if (-1 == xioctl(fd, VIDIOC_S_CROP, &amp;crop)) {
+                        switch (errno) {
+                        case EINVAL:
+                                /* Cropping not supported. */
+                                break;
+                        default:
+                                /* Errors ignored. */
+                                break;
+                        }
+                }
+        } else {
+                /* Errors ignored. */
+        }
+
+
+        CLEAR(fmt);
+
+        fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+        if (force_format) {
+                fmt.fmt.pix.width       = 640;
+                fmt.fmt.pix.height      = 480;
+                fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
+                fmt.fmt.pix.field       = V4L2_FIELD_INTERLACED;
+
+                if (-1 == xioctl(fd, VIDIOC_S_FMT, &amp;fmt))
+                        errno_exit("VIDIOC_S_FMT");
+
+                /* Note VIDIOC_S_FMT may change width and height. */
+        } else {
+                /* Preserve original settings as set by v4l2-ctl for example */
+                if (-1 == xioctl(fd, VIDIOC_G_FMT, &amp;fmt))
+                        errno_exit("VIDIOC_G_FMT");
+        }
+
+        /* Buggy driver paranoia. */
+        min = fmt.fmt.pix.width * 2;
+        if (fmt.fmt.pix.bytesperline &lt; min)
+                fmt.fmt.pix.bytesperline = min;
+        min = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height;
+        if (fmt.fmt.pix.sizeimage &lt; min)
+                fmt.fmt.pix.sizeimage = min;
+
+        switch (io) {
+        case IO_METHOD_READ:
+                init_read(fmt.fmt.pix.sizeimage);
+                break;
+
+        case IO_METHOD_MMAP:
+                init_mmap();
+                break;
+
+        case IO_METHOD_USERPTR:
+                init_userp(fmt.fmt.pix.sizeimage);
+                break;
+        }
+}
+
+static void close_device(void)
+{
+        if (-1 == close(fd))
+                errno_exit("close");
+
+        fd = -1;
+}
+
+static void open_device(void)
+{
+        struct stat st;
+
+        if (-1 == stat(dev_name, &amp;st)) {
+                fprintf(stderr, "Cannot identify '%s': %d, %s\n",
+                         dev_name, errno, strerror(errno));
+                exit(EXIT_FAILURE);
+        }
+
+        if (!S_ISCHR(st.st_mode)) {
+                fprintf(stderr, "%s is no device\n", dev_name);
+                exit(EXIT_FAILURE);
+        }
+
+        fd = open(dev_name, O_RDWR /* required */ | O_NONBLOCK, 0);
+
+        if (-1 == fd) {
+                fprintf(stderr, "Cannot open '%s': %d, %s\n",
+                         dev_name, errno, strerror(errno));
+                exit(EXIT_FAILURE);
+        }
+}
+
+static void usage(FILE *fp, int argc, char **argv)
+{
+        fprintf(fp,
+                 "Usage: %s [options]\n\n"
+                 "Version 1.3\n"
+                 "Options:\n"
+                 "-d | --device name   Video device name [%s]\n"
+                 "-h | --help          Print this message\n"
+                 "-m | --mmap          Use memory mapped buffers [default]\n"
+                 "-r | --read          Use read() calls\n"
+                 "-u | --userp         Use application allocated buffers\n"
+                 "-o | --output        Outputs stream to stdout\n"
+                 "-f | --format        Force format to 640x480 YUYV\n"
+                 "-c | --count         Number of frames to grab [%i]\n"
+                 "",
+                 argv[0], dev_name, frame_count);
+}
+
+static const char short_options[] = "d:hmruofc:";
+
+static const struct option
+long_options[] = {
+        { "device", required_argument, NULL, 'd' },
+        { "help",   no_argument,       NULL, 'h' },
+        { "mmap",   no_argument,       NULL, 'm' },
+        { "read",   no_argument,       NULL, 'r' },
+        { "userp",  no_argument,       NULL, 'u' },
+        { "output", no_argument,       NULL, 'o' },
+        { "format", no_argument,       NULL, 'f' },
+        { "count",  required_argument, NULL, 'c' },
+        { 0, 0, 0, 0 }
+};
+
+int main(int argc, char **argv)
+{
+        dev_name = "/dev/video0";
+
+        for (;;) {
+                int idx;
+                int c;
+
+                c = getopt_long(argc, argv,
+                                short_options, long_options, &amp;idx);
+
+                if (-1 == c)
+                        break;
+
+                switch (c) {
+                case 0: /* getopt_long() flag */
+                        break;
+
+                case 'd':
+                        dev_name = optarg;
+                        break;
+
+                case 'h':
+                        usage(stdout, argc, argv);
+                        exit(EXIT_SUCCESS);
+
+                case 'm':
+                        io = IO_METHOD_MMAP;
+                        break;
+
+                case 'r':
+                        io = IO_METHOD_READ;
+                        break;
+
+                case 'u':
+                        io = IO_METHOD_USERPTR;
+                        break;
+
+                case 'o':
+                        out_buf++;
+                        break;
+
+                case 'f':
+                        force_format++;
+                        break;
+
+                case 'c':
+                        errno = 0;
+                        frame_count = strtol(optarg, NULL, 0);
+                        if (errno)
+                                errno_exit(optarg);
+                        break;
+
+                default:
+                        usage(stderr, argc, argv);
+                        exit(EXIT_FAILURE);
+                }
+        }
+
+        open_device();
+        init_device();
+        start_capturing();
+        mainloop();
+        stop_capturing();
+        uninit_device();
+        close_device();
+        fprintf(stderr, "\n");
+        return 0;
+}
+</programlisting>