Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 664 insertions, 0 deletions

diff --git a/Documentation/userspace-api/media/v4l/capture.c.rst b/Documentation/userspace-api/media/v4l/capture.c.rst
new file mode 100644
index 000000000..eef677296
--- /dev/null
+++ b/Documentation/userspace-api/media/v4l/capture.c.rst
@@ -0,0 +1,664 @@
+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+
+file: media/v4l/capture.c
+=========================
+
+.. code-block:: c
+
+    /*
+     *  V4L2 video capture example
+     *
+     *  This program can be used and distributed without restrictions.
+     *
+     *      This program is provided with the V4L2 API
+     * see https://linuxtv.org/docs.php for more information
+     */
+
+    #include <stdio.h>
+    #include <stdlib.h>
+    #include <string.h>
+    #include <assert.h>
+
+    #include <getopt.h>             /* getopt_long() */
+
+    #include <fcntl.h>              /* low-level i/o */
+    #include <unistd.h>
+    #include <errno.h>
+    #include <sys/stat.h>
+    #include <sys/types.h>
+    #include <sys/time.h>
+    #include <sys/mman.h>
+    #include <sys/ioctl.h>
+
+    #include <linux/videodev2.h>
+
+    #define CLEAR(x) memset(&(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 && 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 v4l2_buffer 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, &buf)) {
+			    switch (errno) {
+			    case EAGAIN:
+				    return 0;
+
+			    case EIO:
+				    /* Could ignore EIO, see spec. */
+
+				    /* fall through */
+
+			    default:
+				    errno_exit("VIDIOC_DQBUF");
+			    }
+		    }
+
+		    assert(buf.index < n_buffers);
+
+		    process_image(buffers[buf.index].start, buf.bytesused);
+
+		    if (-1 == xioctl(fd, VIDIOC_QBUF, &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, &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 < n_buffers; ++i)
+			    if (buf.m.userptr == (unsigned long)buffers[i].start
+				&& buf.length == buffers[i].length)
+				    break;
+
+		    assert(i < n_buffers);
+
+		    process_image((void *)buf.m.userptr, buf.bytesused);
+
+		    if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
+			    errno_exit("VIDIOC_QBUF");
+		    break;
+	    }
+
+	    return 1;
+    }
+
+    static void mainloop(void)
+    {
+	    unsigned int count;
+
+	    count = frame_count;
+
+	    while (count-- > 0) {
+		    for (;;) {
+			    fd_set fds;
+			    struct timeval tv;
+			    int r;
+
+			    FD_ZERO(&fds);
+			    FD_SET(fd, &fds);
+
+			    /* Timeout. */
+			    tv.tv_sec = 2;
+			    tv.tv_usec = 0;
+
+			    r = select(fd + 1, &fds, NULL, NULL, &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 v4l2_buf_type 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, &type))
+			    errno_exit("VIDIOC_STREAMOFF");
+		    break;
+	    }
+    }
+
+    static void start_capturing(void)
+    {
+	    unsigned int i;
+	    enum v4l2_buf_type type;
+
+	    switch (io) {
+	    case IO_METHOD_READ:
+		    /* Nothing to do. */
+		    break;
+
+	    case IO_METHOD_MMAP:
+		    for (i = 0; i < n_buffers; ++i) {
+			    struct v4l2_buffer buf;
+
+			    CLEAR(buf);
+			    buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+			    buf.memory = V4L2_MEMORY_MMAP;
+			    buf.index = i;
+
+			    if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
+				    errno_exit("VIDIOC_QBUF");
+		    }
+		    type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+		    if (-1 == xioctl(fd, VIDIOC_STREAMON, &type))
+			    errno_exit("VIDIOC_STREAMON");
+		    break;
+
+	    case IO_METHOD_USERPTR:
+		    for (i = 0; i < n_buffers; ++i) {
+			    struct v4l2_buffer 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, &buf))
+				    errno_exit("VIDIOC_QBUF");
+		    }
+		    type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+		    if (-1 == xioctl(fd, VIDIOC_STREAMON, &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 < n_buffers; ++i)
+			    if (-1 == munmap(buffers[i].start, buffers[i].length))
+				    errno_exit("munmap");
+		    break;
+
+	    case IO_METHOD_USERPTR:
+		    for (i = 0; i < 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 v4l2_requestbuffers req;
+
+	    CLEAR(req);
+
+	    req.count = 4;
+	    req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	    req.memory = V4L2_MEMORY_MMAP;
+
+	    if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) {
+		    if (EINVAL == errno) {
+			    fprintf(stderr, "%s does not support "
+				     "memory mappingn", dev_name);
+			    exit(EXIT_FAILURE);
+		    } else {
+			    errno_exit("VIDIOC_REQBUFS");
+		    }
+	    }
+
+	    if (req.count < 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 < req.count; ++n_buffers) {
+		    struct v4l2_buffer 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, &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 v4l2_requestbuffers req;
+
+	    CLEAR(req);
+
+	    req.count  = 4;
+	    req.type   = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	    req.memory = V4L2_MEMORY_USERPTR;
+
+	    if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) {
+		    if (EINVAL == errno) {
+			    fprintf(stderr, "%s does not support "
+				     "user pointer i/on", 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 < 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 v4l2_capability cap;
+	    struct v4l2_cropcap cropcap;
+	    struct v4l2_crop crop;
+	    struct v4l2_format fmt;
+	    unsigned int min;
+
+	    if (-1 == xioctl(fd, VIDIOC_QUERYCAP, &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 & 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 & 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 & 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, &cropcap)) {
+		    crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+		    crop.c = cropcap.defrect; /* reset to default */
+
+		    if (-1 == xioctl(fd, VIDIOC_S_CROP, &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, &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, &fmt))
+			    errno_exit("VIDIOC_G_FMT");
+	    }
+
+	    /* Buggy driver paranoia. */
+	    min = fmt.fmt.pix.width * 2;
+	    if (fmt.fmt.pix.bytesperline < min)
+		    fmt.fmt.pix.bytesperline = min;
+	    min = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height;
+	    if (fmt.fmt.pix.sizeimage < 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, &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 devicen", 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, &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;
+    }