/*
 *      uvc_v4l2.c  --  USB Video Class driver - V4L2 API
 *
 *      Copyright (C) 2005-2010
 *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)
 *
 *      This program is free software; you can redistribute it and/or modify
 *      it under the terms of the GNU General Public License as published by
 *      the Free Software Foundation; either version 2 of the License, or
 *      (at your option) any later version.
 *
 */

#include <linux/compat.h>
#include <linux/kernel.h>
#include <linux/version.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/videodev2.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/wait.h>
#include <linux/atomic.h>

#include <media/v4l2-common.h>
#include <media/v4l2-ioctl.h>

#include "uvcvideo.h"

/* ------------------------------------------------------------------------
 * UVC ioctls
 */
static int uvc_ioctl_ctrl_map(struct uvc_video_chain *chain,
        struct uvc_xu_control_mapping *xmap)
{
        struct uvc_control_mapping *map;
        unsigned int size;
        int ret;

        map = kzalloc(sizeof *map, GFP_KERNEL);
        if (map == NULL)
                return -ENOMEM;

        map->id = xmap->id;
        memcpy(map->name, xmap->name, sizeof map->name);
        memcpy(map->entity, xmap->entity, sizeof map->entity);
        map->selector = xmap->selector;
        map->size = xmap->size;
        map->offset = xmap->offset;
        map->v4l2_type = xmap->v4l2_type;
        map->data_type = xmap->data_type;

        switch (xmap->v4l2_type) {
        case V4L2_CTRL_TYPE_INTEGER:
        case V4L2_CTRL_TYPE_BOOLEAN:
        case V4L2_CTRL_TYPE_BUTTON:
                break;

        case V4L2_CTRL_TYPE_MENU:
                /* Prevent excessive memory consumption, as well as integer
                 * overflows.
                 */
                if (xmap->menu_count == 0 ||
                    xmap->menu_count > UVC_MAX_CONTROL_MENU_ENTRIES) {
                        ret = -EINVAL;
                        goto done;
                }

                size = xmap->menu_count * sizeof(*map->menu_info);
                map->menu_info = kmalloc(size, GFP_KERNEL);
                if (map->menu_info == NULL) {
                        ret = -ENOMEM;
                        goto done;
                }

                if (copy_from_user(map->menu_info, xmap->menu_info, size)) {
                        ret = -EFAULT;
                        goto done;
                }

                map->menu_count = xmap->menu_count;
                break;

        default:
                uvc_trace(UVC_TRACE_CONTROL, "Unsupported V4L2 control type "
                          "%u.\n", xmap->v4l2_type);
                ret = -ENOTTY;
                goto done;
        }

        ret = uvc_ctrl_add_mapping(chain, map);

done:
        kfree(map->menu_info);
        kfree(map);

        return ret;
}

/* ------------------------------------------------------------------------
 * V4L2 interface
 */

/*
 * Find the frame interval closest to the requested frame interval for the
 * given frame format and size. This should be done by the device as part of
 * the Video Probe and Commit negotiation, but some hardware don't implement
 * that feature.
 */
static __u32 uvc_try_frame_interval(struct uvc_frame *frame, __u32 interval)
{
        unsigned int i;

        if (frame->bFrameIntervalType) {
                __u32 best = -1, dist;

                for (i = 0; i < frame->bFrameIntervalType; ++i) {
                        dist = interval > frame->dwFrameInterval[i]
                             ? interval - frame->dwFrameInterval[i]
                             : frame->dwFrameInterval[i] - interval;

                        if (dist > best)
                                break;

                        best = dist;
                }

                interval = frame->dwFrameInterval[i-1];
        } else {
                const __u32 min = frame->dwFrameInterval[0];
                const __u32 max = frame->dwFrameInterval[1];
                const __u32 step = frame->dwFrameInterval[2];

                interval = min + (interval - min + step/2) / step * step;
                if (interval > max)
                        interval = max;
        }

        return interval;
}

static int uvc_v4l2_try_format(struct uvc_streaming *stream,
        struct v4l2_format *fmt, struct uvc_streaming_control *probe,
        struct uvc_format **uvc_format, struct uvc_frame **uvc_frame)
{
        struct uvc_format *format = NULL;
        struct uvc_frame *frame = NULL;
        __u16 rw, rh;
        unsigned int d, maxd;
        unsigned int i;
        __u32 interval;
        int ret = 0;
        __u8 *fcc;

        if (fmt->type != stream->type)
                return -EINVAL;

        fcc = (__u8 *)&fmt->fmt.pix.pixelformat;
        uvc_trace(UVC_TRACE_FORMAT, "Trying format 0x%08x (%c%c%c%c): %ux%u.\n",
                        fmt->fmt.pix.pixelformat,
                        fcc[0], fcc[1], fcc[2], fcc[3],
                        fmt->fmt.pix.width, fmt->fmt.pix.height);

        /* Check if the hardware supports the requested format. */
        for (i = 0; i < stream->nformats; ++i) {
                format = &stream->format[i];
                if (format->fcc == fmt->fmt.pix.pixelformat)
                        break;
        }

        if (format == NULL || format->fcc != fmt->fmt.pix.pixelformat) {
                uvc_trace(UVC_TRACE_FORMAT, "Unsupported format 0x%08x.\n",
                                fmt->fmt.pix.pixelformat);
                return -EINVAL;
        }

        /* Find the closest image size. The distance between image sizes is
         * the size in pixels of the non-overlapping regions between the
         * requested size and the frame-specified size.
         */
        rw = fmt->fmt.pix.width;
        rh = fmt->fmt.pix.height;
        maxd = (unsigned int)-1;

        for (i = 0; i < format->nframes; ++i) {
                __u16 w = format->frame[i].wWidth;
                __u16 h = format->frame[i].wHeight;

                d = min(w, rw) * min(h, rh);
                d = w*h + rw*rh - 2*d;
                if (d < maxd) {
                        maxd = d;
                        frame = &format->frame[i];
                }

                if (maxd == 0)
                        break;
        }

        if (frame == NULL) {
                uvc_trace(UVC_TRACE_FORMAT, "Unsupported size %ux%u.\n",
                                fmt->fmt.pix.width, fmt->fmt.pix.height);
                return -EINVAL;
        }

        /* Use the default frame interval. */
        interval = frame->dwDefaultFrameInterval;
        uvc_trace(UVC_TRACE_FORMAT, "Using default frame interval %u.%u us "
                "(%u.%u fps).\n", interval/10, interval%10, 10000000/interval,
                (100000000/interval)%10);

        /* Set the format index, frame index and frame interval. */
        memset(probe, 0, sizeof *probe);
        probe->bmHint = 1;      /* dwFrameInterval */
        probe->bFormatIndex = format->index;
        probe->bFrameIndex = frame->bFrameIndex;
        probe->dwFrameInterval = uvc_try_frame_interval(frame, interval);
        /* Some webcams stall the probe control set request when the
         * dwMaxVideoFrameSize field is set to zero. The UVC specification
         * clearly states that the field is read-only from the host, so this
         * is a webcam bug. Set dwMaxVideoFrameSize to the value reported by
         * the webcam to work around the problem.
         *
         * The workaround could probably be enabled for all webcams, so the
         * quirk can be removed if needed. It's currently useful to detect
         * webcam bugs and fix them before they hit the market (providing
         * developers test their webcams with the Linux driver as well as with
         * the Windows driver).
         */
        mutex_lock(&stream->mutex);
        if (stream->dev->quirks & UVC_QUIRK_PROBE_EXTRAFIELDS)
                probe->dwMaxVideoFrameSize =
                        stream->ctrl.dwMaxVideoFrameSize;

        /* Probe the device. */
        ret = uvc_probe_video(stream, probe);
        mutex_unlock(&stream->mutex);
        if (ret < 0)
                goto done;

        fmt->fmt.pix.width = frame->wWidth;
        fmt->fmt.pix.height = frame->wHeight;
        fmt->fmt.pix.field = V4L2_FIELD_NONE;
        fmt->fmt.pix.bytesperline = format->bpp * frame->wWidth / 8;
        fmt->fmt.pix.sizeimage = probe->dwMaxVideoFrameSize;
        fmt->fmt.pix.colorspace = format->colorspace;
        fmt->fmt.pix.priv = 0;

        if (uvc_format != NULL)
                *uvc_format = format;
        if (uvc_frame != NULL)
                *uvc_frame = frame;

done:
        return ret;
}

static int uvc_v4l2_get_format(struct uvc_streaming *stream,
        struct v4l2_format *fmt)
{
        struct uvc_format *format;
        struct uvc_frame *frame;
        int ret = 0;

        if (fmt->type != stream->type)
                return -EINVAL;

        mutex_lock(&stream->mutex);
        format = stream->cur_format;
        frame = stream->cur_frame;

        if (format == NULL || frame == NULL) {
                ret = -EINVAL;
                goto done;
        }

        fmt->fmt.pix.pixelformat = format->fcc;
        fmt->fmt.pix.width = frame->wWidth;
        fmt->fmt.pix.height = frame->wHeight;
        fmt->fmt.pix.field = V4L2_FIELD_NONE;
        fmt->fmt.pix.bytesperline = format->bpp * frame->wWidth / 8;
        fmt->fmt.pix.sizeimage = stream->ctrl.dwMaxVideoFrameSize;
        fmt->fmt.pix.colorspace = format->colorspace;
        fmt->fmt.pix.priv = 0;

done:
        mutex_unlock(&stream->mutex);
        return ret;
}

static int uvc_v4l2_set_format(struct uvc_streaming *stream,
        struct v4l2_format *fmt)
{
        struct uvc_streaming_control probe;
        struct uvc_format *format;
        struct uvc_frame *frame;
        int ret;

        if (fmt->type != stream->type)
                return -EINVAL;

        ret = uvc_v4l2_try_format(stream, fmt, &probe, &format, &frame);
        if (ret < 0)
                return ret;

        mutex_lock(&stream->mutex);

        if (uvc_queue_allocated(&stream->queue)) {
                ret = -EBUSY;
                goto done;
        }

        memcpy(&stream->ctrl, &probe, sizeof probe);
        stream->cur_format = format;
        stream->cur_frame = frame;

done:
        mutex_unlock(&stream->mutex);
        return ret;
}

static int uvc_v4l2_get_streamparm(struct uvc_streaming *stream,
                struct v4l2_streamparm *parm)
{
        uint32_t numerator, denominator;

        if (parm->type != stream->type)
                return -EINVAL;

        mutex_lock(&stream->mutex);
        numerator = stream->ctrl.dwFrameInterval;
        mutex_unlock(&stream->mutex);

        denominator = 10000000;
        uvc_simplify_fraction(&numerator, &denominator, 8, 333);

        memset(parm, 0, sizeof *parm);
        parm->type = stream->type;

        if (stream->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
                parm->parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
                parm->parm.capture.capturemode = 0;
                parm->parm.capture.timeperframe.numerator = numerator;
                parm->parm.capture.timeperframe.denominator = denominator;
                parm->parm.capture.extendedmode = 0;
                parm->parm.capture.readbuffers = 0;
        } else {
                parm->parm.output.capability = V4L2_CAP_TIMEPERFRAME;
                parm->parm.output.outputmode = 0;
                parm->parm.output.timeperframe.numerator = numerator;
                parm->parm.output.timeperframe.denominator = denominator;
        }

        return 0;
}

static int uvc_v4l2_set_streamparm(struct uvc_streaming *stream,
                struct v4l2_streamparm *parm)
{
        struct uvc_streaming_control probe;
        struct v4l2_fract timeperframe;
        uint32_t interval;
        int ret;

        if (parm->type != stream->type)
                return -EINVAL;

        if (parm->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
                timeperframe = parm->parm.capture.timeperframe;
        else
                timeperframe = parm->parm.output.timeperframe;

        interval = uvc_fraction_to_interval(timeperframe.numerator,
                timeperframe.denominator);
        uvc_trace(UVC_TRACE_FORMAT, "Setting frame interval to %u/%u (%u).\n",
                timeperframe.numerator, timeperframe.denominator, interval);

        mutex_lock(&stream->mutex);

        if (uvc_queue_streaming(&stream->queue)) {
                mutex_unlock(&stream->mutex);
                return -EBUSY;
        }

        memcpy(&probe, &stream->ctrl, sizeof probe);
        probe.dwFrameInterval =
                uvc_try_frame_interval(stream->cur_frame, interval);

        /* Probe the device with the new settings. */
        ret = uvc_probe_video(stream, &probe);
        if (ret < 0) {
                mutex_unlock(&stream->mutex);
                return ret;
        }

        memcpy(&stream->ctrl, &probe, sizeof probe);
        mutex_unlock(&stream->mutex);

        /* Return the actual frame period. */
        timeperframe.numerator = probe.dwFrameInterval;
        timeperframe.denominator = 10000000;
        uvc_simplify_fraction(&timeperframe.numerator,
                &timeperframe.denominator, 8, 333);

        if (parm->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
                parm->parm.capture.timeperframe = timeperframe;
        else
                parm->parm.output.timeperframe = timeperframe;

        return 0;
}

/* ------------------------------------------------------------------------
 * Privilege management
 */

/*
 * Privilege management is the multiple-open implementation basis. The current
 * implementation is completely transparent for the end-user and doesn't
 * require explicit use of the VIDIOC_G_PRIORITY and VIDIOC_S_PRIORITY ioctls.
 * Those ioctls enable finer control on the device (by making possible for a
 * user to request exclusive access to a device), but are not mature yet.
 * Switching to the V4L2 priority mechanism might be considered in the future
 * if this situation changes.
 *
 * Each open instance of a UVC device can either be in a privileged or
 * unprivileged state. Only a single instance can be in a privileged state at
 * a given time. Trying to perform an operation that requires privileges will
 * automatically acquire the required privileges if possible, or return -EBUSY
 * otherwise. Privileges are dismissed when closing the instance or when
 * freeing the video buffers using VIDIOC_REQBUFS.
 *
 * Operations that require privileges are:
 *
 * - VIDIOC_S_INPUT
 * - VIDIOC_S_PARM
 * - VIDIOC_S_FMT
 * - VIDIOC_REQBUFS
 */
static int uvc_acquire_privileges(struct uvc_fh *handle)
{
        /* Always succeed if the handle is already privileged. */
        if (handle->state == UVC_HANDLE_ACTIVE)
                return 0;

        /* Check if the device already has a privileged handle. */
        if (atomic_inc_return(&handle->stream->active) != 1) {
                atomic_dec(&handle->stream->active);
                return -EBUSY;
        }

        handle->state = UVC_HANDLE_ACTIVE;
        return 0;
}

static void uvc_dismiss_privileges(struct uvc_fh *handle)
{
        if (handle->state == UVC_HANDLE_ACTIVE)
                atomic_dec(&handle->stream->active);

        handle->state = UVC_HANDLE_PASSIVE;
}

static int uvc_has_privileges(struct uvc_fh *handle)
{
        return handle->state == UVC_HANDLE_ACTIVE;
}

/* ------------------------------------------------------------------------
 * V4L2 file operations
 */

static int uvc_v4l2_open(struct file *file)
{
        struct uvc_streaming *stream;
        struct uvc_fh *handle;
        int ret = 0;

        uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_open\n");
        stream = video_drvdata(file);

        if (stream->dev->state & UVC_DEV_DISCONNECTED)
                return -ENODEV;

        ret = usb_autopm_get_interface(stream->dev->intf);
        if (ret < 0)
                return ret;

        /* Create the device handle. */
        handle = kzalloc(sizeof *handle, GFP_KERNEL);
        if (handle == NULL) {
                usb_autopm_put_interface(stream->dev->intf);
                return -ENOMEM;
        }

        if (atomic_inc_return(&stream->dev->users) == 1) {
                ret = uvc_status_start(stream->dev);
                if (ret < 0) {
                        usb_autopm_put_interface(stream->dev->intf);
                        atomic_dec(&stream->dev->users);
                        kfree(handle);
                        return ret;
                }
        }

        handle->chain = stream->chain;
        handle->stream = stream;
        handle->state = UVC_HANDLE_PASSIVE;
        file->private_data = handle;

        return 0;
}

static int uvc_v4l2_release(struct file *file)
{
        struct uvc_fh *handle = file->private_data;
        struct uvc_streaming *stream = handle->stream;

        uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_release\n");

        /* Only free resources if this is a privileged handle. */
        if (uvc_has_privileges(handle)) {
                uvc_video_enable(stream, 0);
                uvc_free_buffers(&stream->queue);
        }

        /* Release the file handle. */
        uvc_dismiss_privileges(handle);
        kfree(handle);
        file->private_data = NULL;

        if (atomic_dec_return(&stream->dev->users) == 0)
                uvc_status_stop(stream->dev);

        usb_autopm_put_interface(stream->dev->intf);
        return 0;
}

static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
{
        struct video_device *vdev = video_devdata(file);
        struct uvc_fh *handle = file->private_data;
        struct uvc_video_chain *chain = handle->chain;
        struct uvc_streaming *stream = handle->stream;
        long ret = 0;

        switch (cmd) {
        /* Query capabilities */
        case VIDIOC_QUERYCAP:
        {
                struct v4l2_capability *cap = arg;

                memset(cap, 0, sizeof *cap);
                strlcpy(cap->driver, "uvcvideo", sizeof cap->driver);
                strlcpy(cap->card, vdev->name, sizeof cap->card);
                usb_make_path(stream->dev->udev,
                              cap->bus_info, sizeof(cap->bus_info));
                cap->version = LINUX_VERSION_CODE;
                if (stream->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
                        cap->capabilities = V4L2_CAP_VIDEO_CAPTURE
                                          | V4L2_CAP_STREAMING;
                else
                        cap->capabilities = V4L2_CAP_VIDEO_OUTPUT
                                          | V4L2_CAP_STREAMING;
                break;
        }

        /* Get, Set & Query control */
        case VIDIOC_QUERYCTRL:
                return uvc_query_v4l2_ctrl(chain, arg);

        case VIDIOC_G_CTRL:
        {
                struct v4l2_control *ctrl = arg;
                struct v4l2_ext_control xctrl;

                memset(&xctrl, 0, sizeof xctrl);
                xctrl.id = ctrl->id;

                ret = uvc_ctrl_begin(chain);
                if (ret < 0)
                        return ret;

                ret = uvc_ctrl_get(chain, &xctrl);
                uvc_ctrl_rollback(chain);
                if (ret >= 0)
                        ctrl->value = xctrl.value;
                break;
        }

        case VIDIOC_S_CTRL:
        {
                struct v4l2_control *ctrl = arg;
                struct v4l2_ext_control xctrl;

                memset(&xctrl, 0, sizeof xctrl);
                xctrl.id = ctrl->id;
                xctrl.value = ctrl->value;

                ret = uvc_ctrl_begin(chain);
                if (ret < 0)
                        return ret;

                ret = uvc_ctrl_set(chain, &xctrl);
                if (ret < 0) {
                        uvc_ctrl_rollback(chain);
                        return ret;
                }
                ret = uvc_ctrl_commit(chain);
                if (ret == 0)
                        ctrl->value = xctrl.value;
                break;
        }

        case VIDIOC_QUERYMENU:
                return uvc_query_v4l2_menu(chain, arg);

        case VIDIOC_G_EXT_CTRLS:
        {
                struct v4l2_ext_controls *ctrls = arg;
                struct v4l2_ext_control *ctrl = ctrls->controls;
                unsigned int i;

                ret = uvc_ctrl_begin(chain);
                if (ret < 0)
                        return ret;

                for (i = 0; i < ctrls->count; ++ctrl, ++i) {
                        ret = uvc_ctrl_get(chain, ctrl);
                        if (ret < 0) {
                                uvc_ctrl_rollback(chain);
                                ctrls->error_idx = i;
                                return ret;
                        }
                }
                ctrls->error_idx = 0;
                ret = uvc_ctrl_rollback(chain);
                break;
        }

        case VIDIOC_S_EXT_CTRLS:
        case VIDIOC_TRY_EXT_CTRLS:
        {
                struct v4l2_ext_controls *ctrls = arg;
                struct v4l2_ext_control *ctrl = ctrls->controls;
                unsigned int i;

                ret = uvc_ctrl_begin(chain);
                if (ret < 0)
                        return ret;

                for (i = 0; i < ctrls->count; ++ctrl, ++i) {
                        ret = uvc_ctrl_set(chain, ctrl);
                        if (ret < 0) {
                                uvc_ctrl_rollback(chain);
                                ctrls->error_idx = i;
                                return ret;
                        }
                }

                ctrls->error_idx = 0;

                if (cmd == VIDIOC_S_EXT_CTRLS)
                        ret = uvc_ctrl_commit(chain);
                else
                        ret = uvc_ctrl_rollback(chain);
                break;
        }

        /* Get, Set & Enum input */
        case VIDIOC_ENUMINPUT:
        {
                const struct uvc_entity *selector = chain->selector;
                struct v4l2_input *input = arg;
                struct uvc_entity *iterm = NULL;
                u32 index = input->index;
                int pin = 0;

                if (selector == NULL ||
                    (chain->dev->quirks & UVC_QUIRK_IGNORE_SELECTOR_UNIT)) {
                        if (index != 0)
                                return -EINVAL;
                        list_for_each_entry(iterm, &chain->entities, chain) {
                                if (UVC_ENTITY_IS_ITERM(iterm))
                                        break;
                        }
                        pin = iterm->id;
                } else if (pin < selector->bNrInPins) {
                        pin = selector->baSourceID[index];
                        list_for_each_entry(iterm, &chain->entities, chain) {
                                if (!UVC_ENTITY_IS_ITERM(iterm))
                                        continue;
                                if (iterm->id == pin)
                                        break;
                        }
                }

                if (iterm == NULL || iterm->id != pin)
                        return -EINVAL;

                memset(input, 0, sizeof *input);
                input->index = index;
                strlcpy(input->name, iterm->name, sizeof input->name);
                if (UVC_ENTITY_TYPE(iterm) == UVC_ITT_CAMERA)
                        input->type = V4L2_INPUT_TYPE_CAMERA;
                break;
        }

        case VIDIOC_G_INPUT:
        {
                u8 input;

                if (chain->selector == NULL ||
                    (chain->dev->quirks & UVC_QUIRK_IGNORE_SELECTOR_UNIT)) {
                        *(int *)arg = 0;
                        break;
                }

                ret = uvc_query_ctrl(chain->dev, UVC_GET_CUR,
                        chain->selector->id, chain->dev->intfnum,
                        UVC_SU_INPUT_SELECT_CONTROL, &input, 1);
                if (ret < 0)
                        return ret;

                *(int *)arg = input - 1;
                break;
        }

        case VIDIOC_S_INPUT:
        {
                u32 input = *(u32 *)arg + 1;

                if ((ret = uvc_acquire_privileges(handle)) < 0)
                        return ret;

                if (chain->selector == NULL ||
                    (chain->dev->quirks & UVC_QUIRK_IGNORE_SELECTOR_UNIT)) {
                        if (input != 1)
                                return -EINVAL;
                        break;
                }

                if (input == 0 || input > chain->selector->bNrInPins)
                        return -EINVAL;

                return uvc_query_ctrl(chain->dev, UVC_SET_CUR,
                        chain->selector->id, chain->dev->intfnum,
                        UVC_SU_INPUT_SELECT_CONTROL, &input, 1);
        }

        /* Try, Get, Set & Enum format */
        case VIDIOC_ENUM_FMT:
        {
                struct v4l2_fmtdesc *fmt = arg;
                struct uvc_format *format;
                enum v4l2_buf_type type = fmt->type;
                __u32 index = fmt->index;

                if (fmt->type != stream->type ||
                    fmt->index >= stream->nformats)
                        return -EINVAL;

                memset(fmt, 0, sizeof(*fmt));
                fmt->index = index;
                fmt->type = type;

                format = &stream->format[fmt->index];
                fmt->flags = 0;
                if (format->flags & UVC_FMT_FLAG_COMPRESSED)
                        fmt->flags |= V4L2_FMT_FLAG_COMPRESSED;
                strlcpy(fmt->description, format->name,
                        sizeof fmt->description);
                fmt->description[sizeof fmt->description - 1] = 0;
                fmt->pixelformat = format->fcc;
                break;
        }

        case VIDIOC_TRY_FMT:
        {
                struct uvc_streaming_control probe;

                return uvc_v4l2_try_format(stream, arg, &probe, NULL, NULL);
        }

        case VIDIOC_S_FMT:
                if ((ret = uvc_acquire_privileges(handle)) < 0)
                        return ret;

                return uvc_v4l2_set_format(stream, arg);

        case VIDIOC_G_FMT:
                return uvc_v4l2_get_format(stream, arg);

        /* Frame size enumeration */
        case VIDIOC_ENUM_FRAMESIZES:
        {
                struct v4l2_frmsizeenum *fsize = arg;
                struct uvc_format *format = NULL;
                struct uvc_frame *frame;
                int i;

                /* Look for the given pixel format */
                for (i = 0; i < stream->nformats; i++) {
                        if (stream->format[i].fcc ==
                                        fsize->pixel_format) {
                                format = &stream->format[i];
                                break;
                        }
                }
                if (format == NULL)
                        return -EINVAL;

                if (fsize->index >= format->nframes)
                        return -EINVAL;

                frame = &format->frame[fsize->index];
                fsize->type = V4L2_FRMSIZE_TYPE_DISCRETE;
                fsize->discrete.width = frame->wWidth;
                fsize->discrete.height = frame->wHeight;
                break;
        }

        /* Frame interval enumeration */
        case VIDIOC_ENUM_FRAMEINTERVALS:
        {
                struct v4l2_frmivalenum *fival = arg;
                struct uvc_format *format = NULL;
                struct uvc_frame *frame = NULL;
                int i;

                /* Look for the given pixel format and frame size */
                for (i = 0; i < stream->nformats; i++) {
                        if (stream->format[i].fcc ==
                                        fival->pixel_format) {
                                format = &stream->format[i];
                                break;
                        }
                }
                if (format == NULL)
                        return -EINVAL;

                for (i = 0; i < format->nframes; i++) {
                        if (format->frame[i].wWidth == fival->width &&
                            format->frame[i].wHeight == fival->height) {
                                frame = &format->frame[i];
                                break;
                        }
                }
                if (frame == NULL)
                        return -EINVAL;

                if (frame->bFrameIntervalType) {
                        if (fival->index >= frame->bFrameIntervalType)
                                return -EINVAL;

                        fival->type = V4L2_FRMIVAL_TYPE_DISCRETE;
                        fival->discrete.numerator =
                                frame->dwFrameInterval[fival->index];
                        fival->discrete.denominator = 10000000;
                        uvc_simplify_fraction(&fival->discrete.numerator,
                                &fival->discrete.denominator, 8, 333);
                } else {
                        fival->type = V4L2_FRMIVAL_TYPE_STEPWISE;
                        fival->stepwise.min.numerator =
                                frame->dwFrameInterval[0];
                        fival->stepwise.min.denominator = 10000000;
                        fival->stepwise.max.numerator =
                                frame->dwFrameInterval[1];
                        fival->stepwise.max.denominator = 10000000;
                        fival->stepwise.step.numerator =
                                frame->dwFrameInterval[2];
                        fival->stepwise.step.denominator = 10000000;
                        uvc_simplify_fraction(&fival->stepwise.min.numerator,
                                &fival->stepwise.min.denominator, 8, 333);
                        uvc_simplify_fraction(&fival->stepwise.max.numerator,
                                &fival->stepwise.max.denominator, 8, 333);
                        uvc_simplify_fraction(&fival->stepwise.step.numerator,
                                &fival->stepwise.step.denominator, 8, 333);
                }
                break;
        }

        /* Get & Set streaming parameters */
        case VIDIOC_G_PARM:
                return uvc_v4l2_get_streamparm(stream, arg);

        case VIDIOC_S_PARM:
                if ((ret = uvc_acquire_privileges(handle)) < 0)
                        return ret;

                return uvc_v4l2_set_streamparm(stream, arg);

        /* Cropping and scaling */
        case VIDIOC_CROPCAP:
        {
                struct v4l2_cropcap *ccap = arg;

                if (ccap->type != stream->type)
                        return -EINVAL;

                ccap->bounds.left = 0;
                ccap->bounds.top = 0;

                mutex_lock(&stream->mutex);
                ccap->bounds.width = stream->cur_frame->wWidth;
                ccap->bounds.height = stream->cur_frame->wHeight;
                mutex_unlock(&stream->mutex);

                ccap->defrect = ccap->bounds;

                ccap->pixelaspect.numerator = 1;
                ccap->pixelaspect.denominator = 1;
                break;
        }

        case VIDIOC_G_CROP:
        case VIDIOC_S_CROP:
                return -EINVAL;

        /* Buffers & streaming */
        case VIDIOC_REQBUFS:
                if ((ret = uvc_acquire_privileges(handle)) < 0)
                        return ret;

                mutex_lock(&stream->mutex);
                ret = uvc_alloc_buffers(&stream->queue, arg);
                mutex_unlock(&stream->mutex);
                if (ret < 0)
                        return ret;

                if (ret == 0)
                        uvc_dismiss_privileges(handle);

                ret = 0;
                break;

        case VIDIOC_QUERYBUF:
        {
                struct v4l2_buffer *buf = arg;

                if (!uvc_has_privileges(handle))
                        return -EBUSY;

                return uvc_query_buffer(&stream->queue, buf);
        }

        case VIDIOC_QBUF:
                if (!uvc_has_privileges(handle))
                        return -EBUSY;

                return uvc_queue_buffer(&stream->queue, arg);

        case VIDIOC_DQBUF:
                if (!uvc_has_privileges(handle))
                        return -EBUSY;

                return uvc_dequeue_buffer(&stream->queue, arg,
                        file->f_flags & O_NONBLOCK);

        case VIDIOC_STREAMON:
        {
                int *type = arg;

                if (*type != stream->type)
                        return -EINVAL;

                if (!uvc_has_privileges(handle))
                        return -EBUSY;

                mutex_lock(&stream->mutex);
                ret = uvc_video_enable(stream, 1);
                mutex_unlock(&stream->mutex);
                if (ret < 0)
                        return ret;
                break;
        }

        case VIDIOC_STREAMOFF:
        {
                int *type = arg;

                if (*type != stream->type)
                        return -EINVAL;

                if (!uvc_has_privileges(handle))
                        return -EBUSY;

                return uvc_video_enable(stream, 0);
        }

        /* Analog video standards make no sense for digital cameras. */
        case VIDIOC_ENUMSTD:
        case VIDIOC_QUERYSTD:
        case VIDIOC_G_STD:
        case VIDIOC_S_STD:

        case VIDIOC_OVERLAY:

        case VIDIOC_ENUMAUDIO:
        case VIDIOC_ENUMAUDOUT:

        case VIDIOC_ENUMOUTPUT:
                uvc_trace(UVC_TRACE_IOCTL, "Unsupported ioctl 0x%08x\n", cmd);
                return -EINVAL;

        case UVCIOC_CTRL_MAP:
                return uvc_ioctl_ctrl_map(chain, arg);

        case UVCIOC_CTRL_QUERY:
                return uvc_xu_ctrl_query(chain, arg);

        default:
                uvc_trace(UVC_TRACE_IOCTL, "Unknown ioctl 0x%08x\n", cmd);
                return -ENOTTY;
        }

        return ret;
}

static long uvc_v4l2_ioctl(struct file *file,
                     unsigned int cmd, unsigned long arg)
{
        if (uvc_trace_param & UVC_TRACE_IOCTL) {
                uvc_printk(KERN_DEBUG, "uvc_v4l2_ioctl(");
                v4l_printk_ioctl(cmd);
                printk(")\n");
        }

        return video_usercopy(file, cmd, arg, uvc_v4l2_do_ioctl);
}

#ifdef CONFIG_COMPAT
struct uvc_xu_control_mapping32 {
        __u32 id;
        __u8 name[32];
        __u8 entity[16];
        __u8 selector;

        __u8 size;
        __u8 offset;
        __u32 v4l2_type;
        __u32 data_type;

        compat_caddr_t menu_info;
        __u32 menu_count;

        __u32 reserved[4];
};

static int uvc_v4l2_get_xu_mapping(struct uvc_xu_control_mapping *kp,
                        const struct uvc_xu_control_mapping32 __user *up)
{
        struct uvc_menu_info __user *umenus;
        struct uvc_menu_info __user *kmenus;
        compat_caddr_t p;

        if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
            __copy_from_user(kp, up, offsetof(typeof(*up), menu_info)) ||
            __get_user(kp->menu_count, &up->menu_count))
                return -EFAULT;

        memset(kp->reserved, 0, sizeof(kp->reserved));

        if (kp->menu_count == 0) {
                kp->menu_info = NULL;
                return 0;
        }

        if (__get_user(p, &up->menu_info))
                return -EFAULT;
        umenus = compat_ptr(p);
        if (!access_ok(VERIFY_READ, umenus, kp->menu_count * sizeof(*umenus)))
                return -EFAULT;

        kmenus = compat_alloc_user_space(kp->menu_count * sizeof(*kmenus));
        if (kmenus == NULL)
                return -EFAULT;
        kp->menu_info = kmenus;

        if (copy_in_user(kmenus, umenus, kp->menu_count * sizeof(*umenus)))
                return -EFAULT;

        return 0;
}

static int uvc_v4l2_put_xu_mapping(const struct uvc_xu_control_mapping *kp,
                        struct uvc_xu_control_mapping32 __user *up)
{
        struct uvc_menu_info __user *umenus;
        struct uvc_menu_info __user *kmenus = kp->menu_info;
        compat_caddr_t p;

        if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
            __copy_to_user(up, kp, offsetof(typeof(*up), menu_info)) ||
            __put_user(kp->menu_count, &up->menu_count))
                return -EFAULT;

        __clear_user(up->reserved, sizeof(up->reserved));

        if (kp->menu_count == 0)
                return 0;

        if (get_user(p, &up->menu_info))
                return -EFAULT;
        umenus = compat_ptr(p);
        if (!access_ok(VERIFY_WRITE, umenus, kp->menu_count * sizeof(*umenus)))
                return -EFAULT;

        if (copy_in_user(umenus, kmenus, kp->menu_count * sizeof(*umenus)))
                return -EFAULT;

        return 0;
}

struct uvc_xu_control_query32 {
        __u8 unit;
        __u8 selector;
        __u8 query;
        __u16 size;
        compat_caddr_t data;
};

static int uvc_v4l2_get_xu_query(struct uvc_xu_control_query *kp,
                        const struct uvc_xu_control_query32 __user *up)
{
        u8 __user *udata;
        u8 __user *kdata;
        compat_caddr_t p;

        if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
            __copy_from_user(kp, up, offsetof(typeof(*up), data)))
                return -EFAULT;

        if (kp->size == 0) {
                kp->data = NULL;
                return 0;
        }

        if (__get_user(p, &up->data))
                return -EFAULT;
        udata = compat_ptr(p);
        if (!access_ok(VERIFY_READ, udata, kp->size))
                return -EFAULT;

        kdata = compat_alloc_user_space(kp->size);
        if (kdata == NULL)
                return -EFAULT;
        kp->data = kdata;

        if (copy_in_user(kdata, udata, kp->size))
                return -EFAULT;

        return 0;
}

static int uvc_v4l2_put_xu_query(const struct uvc_xu_control_query *kp,
                        struct uvc_xu_control_query32 __user *up)
{
        u8 __user *udata;
        u8 __user *kdata = kp->data;
        compat_caddr_t p;

        if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
            __copy_to_user(up, kp, offsetof(typeof(*up), data)))
                return -EFAULT;

        if (kp->size == 0)
                return 0;

        if (get_user(p, &up->data))
                return -EFAULT;
        udata = compat_ptr(p);
        if (!access_ok(VERIFY_READ, udata, kp->size))
                return -EFAULT;

        if (copy_in_user(udata, kdata, kp->size))
                return -EFAULT;

        return 0;
}

#define UVCIOC_CTRL_MAP32       _IOWR('u', 0x20, struct uvc_xu_control_mapping32)
#define UVCIOC_CTRL_QUERY32     _IOWR('u', 0x21, struct uvc_xu_control_query32)

static long uvc_v4l2_compat_ioctl32(struct file *file,
                     unsigned int cmd, unsigned long arg)
{
        union {
                struct uvc_xu_control_mapping xmap;
                struct uvc_xu_control_query xqry;
        } karg;
        void __user *up = compat_ptr(arg);
        mm_segment_t old_fs;
        long ret;

        switch (cmd) {
        case UVCIOC_CTRL_MAP32:
                cmd = UVCIOC_CTRL_MAP;
                ret = uvc_v4l2_get_xu_mapping(&karg.xmap, up);
                break;

        case UVCIOC_CTRL_QUERY32:
                cmd = UVCIOC_CTRL_QUERY;
                ret = uvc_v4l2_get_xu_query(&karg.xqry, up);
                break;

        default:
                return -ENOIOCTLCMD;
        }

        old_fs = get_fs();
        set_fs(KERNEL_DS);
        ret = uvc_v4l2_ioctl(file, cmd, (unsigned long)&karg);
        set_fs(old_fs);

        if (ret < 0)
                return ret;

        switch (cmd) {
        case UVCIOC_CTRL_MAP:
                ret = uvc_v4l2_put_xu_mapping(&karg.xmap, up);
                break;

        case UVCIOC_CTRL_QUERY:
                ret = uvc_v4l2_put_xu_query(&karg.xqry, up);
                break;
        }

        return ret;
}
#endif

static ssize_t uvc_v4l2_read(struct file *file, char __user *data,
                    size_t count, loff_t *ppos)
{
        uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_read: not implemented.\n");
        return -EINVAL;
}

static int uvc_v4l2_mmap(struct file *file, struct vm_area_struct *vma)
{
        struct uvc_fh *handle = file->private_data;
        struct uvc_streaming *stream = handle->stream;

        uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_mmap\n");

        return uvc_queue_mmap(&stream->queue, vma);
}

static unsigned int uvc_v4l2_poll(struct file *file, poll_table *wait)
{
        struct uvc_fh *handle = file->private_data;
        struct uvc_streaming *stream = handle->stream;

        uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_poll\n");

        return uvc_queue_poll(&stream->queue, file, wait);
}

#ifndef CONFIG_MMU
static unsigned long uvc_v4l2_get_unmapped_area(struct file *file,
                unsigned long addr, unsigned long len, unsigned long pgoff,
                unsigned long flags)
{
        struct uvc_fh *handle = file->private_data;
        struct uvc_streaming *stream = handle->stream;

        uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_get_unmapped_area\n");

        return uvc_queue_get_unmapped_area(&stream->queue, pgoff);
}
#endif

const struct v4l2_file_operations uvc_fops = {
        .owner          = THIS_MODULE,
        .open           = uvc_v4l2_open,
        .release        = uvc_v4l2_release,
        .unlocked_ioctl = uvc_v4l2_ioctl,
#ifdef CONFIG_COMPAT
        .compat_ioctl32 = uvc_v4l2_compat_ioctl32,
#endif
        .read           = uvc_v4l2_read,
        .mmap           = uvc_v4l2_mmap,
        .poll           = uvc_v4l2_poll,
#ifndef CONFIG_MMU
        .get_unmapped_area = uvc_v4l2_get_unmapped_area,
#endif
};