Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

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;
+    }