uvc_v4l2.c

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/*
 *  uvc_v4l2.c  --  USB Video Class Gadget driver
 *
 *  Copyright (C) 2009-2010
 *      Laurent Pinchart ([email protected])
 *
 *  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/kernel.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/videodev2.h>
#include <linux/vmalloc.h>
#include <linux/wait.h>

#include <media/v4l2-dev.h>
#include <media/v4l2-event.h>
#include <media/v4l2-ioctl.h>

#include "uvc.h"
#include "uvc_queue.h"

/* --------------------------------------------------------------------------
 * Requests handling
 */

static int
uvc_send_response(struct uvc_device *uvc, struct uvc_request_data *data)
{
    struct usb_composite_dev *cdev = uvc->func.config->cdev;
    struct usb_request *req = uvc->control_req;

    if (data->length < 0)
        return usb_ep_set_halt(cdev->gadget->ep0);

    req->length = min_t(unsigned int, uvc->event_length, data->length);
    req->zero = data->length < uvc->event_length;
    req->dma = DMA_ADDR_INVALID;

    memcpy(req->buf, data->data, data->length);

    return usb_ep_queue(cdev->gadget->ep0, req, GFP_KERNEL);
}

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

struct uvc_format
{
    u8 bpp;
    u32 fcc;
};

static struct uvc_format uvc_formats[] = {
    { 16, V4L2_PIX_FMT_YUYV  },
    { 0,  V4L2_PIX_FMT_MJPEG },
};

static int
uvc_v4l2_get_format(struct uvc_video *video, struct v4l2_format *fmt)
{
    fmt->fmt.pix.pixelformat = video->fcc;
    fmt->fmt.pix.width = video->width;
    fmt->fmt.pix.height = video->height;
    fmt->fmt.pix.field = V4L2_FIELD_NONE;
    fmt->fmt.pix.bytesperline = video->bpp * video->width / 8;
    fmt->fmt.pix.sizeimage = video->imagesize;
    fmt->fmt.pix.colorspace = V4L2_COLORSPACE_SRGB;
    fmt->fmt.pix.priv = 0;

    return 0;
}

static int
uvc_v4l2_set_format(struct uvc_video *video, struct v4l2_format *fmt)
{
    struct uvc_format *format;
    unsigned int imagesize;
    unsigned int bpl;
    unsigned int i;

    for (i = 0; i < ARRAY_SIZE(uvc_formats); ++i) {
        format = &uvc_formats[i];
        if (format->fcc == fmt->fmt.pix.pixelformat)
            break;
    }

    if (i == ARRAY_SIZE(uvc_formats)) {
        printk(KERN_INFO "Unsupported format 0x%08x.\n",
            fmt->fmt.pix.pixelformat);
        return -EINVAL;
    }

    bpl = format->bpp * fmt->fmt.pix.width / 8;
    imagesize = bpl ? bpl * fmt->fmt.pix.height : fmt->fmt.pix.sizeimage;

    video->fcc = format->fcc;
    video->bpp = format->bpp;
    video->width = fmt->fmt.pix.width;
    video->height = fmt->fmt.pix.height;
    video->imagesize = imagesize;

    fmt->fmt.pix.field = V4L2_FIELD_NONE;
    fmt->fmt.pix.bytesperline = bpl;
    fmt->fmt.pix.sizeimage = imagesize;
    fmt->fmt.pix.colorspace = V4L2_COLORSPACE_SRGB;
    fmt->fmt.pix.priv = 0;

    return 0;
}

static int
uvc_v4l2_open(struct file *file)
{
    struct video_device *vdev = video_devdata(file);
    struct uvc_device *uvc = video_get_drvdata(vdev);
    struct uvc_file_handle *handle;

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

    v4l2_fh_init(&handle->vfh, vdev);
    v4l2_fh_add(&handle->vfh);

    handle->device = &uvc->video;
    file->private_data = &handle->vfh;

    uvc_function_connect(uvc);
    return 0;
}

static int
uvc_v4l2_release(struct file *file)
{
    struct video_device *vdev = video_devdata(file);
    struct uvc_device *uvc = video_get_drvdata(vdev);
    struct uvc_file_handle *handle = to_uvc_file_handle(file->private_data);
    struct uvc_video *video = handle->device;

    uvc_function_disconnect(uvc);

    uvc_video_enable(video, 0);
    mutex_lock(&video->queue.mutex);
    if (uvc_free_buffers(&video->queue) < 0)
        printk(KERN_ERR "uvc_v4l2_release: Unable to free "
                "buffers.\n");
    mutex_unlock(&video->queue.mutex);

    file->private_data = NULL;
    v4l2_fh_del(&handle->vfh);
    v4l2_fh_exit(&handle->vfh);
    kfree(handle);
    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_device *uvc = video_get_drvdata(vdev);
    struct uvc_file_handle *handle = to_uvc_file_handle(file->private_data);
    struct usb_composite_dev *cdev = uvc->func.config->cdev;
    struct uvc_video *video = &uvc->video;
    int ret = 0;

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

        memset(cap, 0, sizeof *cap);
        strncpy(cap->driver, "g_uvc", sizeof(cap->driver));
        strncpy(cap->card, cdev->gadget->name, sizeof(cap->card));
        strncpy(cap->bus_info, dev_name(&cdev->gadget->dev),
            sizeof cap->bus_info);
        cap->version = DRIVER_VERSION_NUMBER;
        cap->capabilities = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;
        break;
    }

    /* Get & Set format */
    case VIDIOC_G_FMT:
    {
        struct v4l2_format *fmt = arg;

        if (fmt->type != video->queue.type)
            return -EINVAL;

        return uvc_v4l2_get_format(video, fmt);
    }

    case VIDIOC_S_FMT:
    {
        struct v4l2_format *fmt = arg;

        if (fmt->type != video->queue.type)
            return -EINVAL;

        return uvc_v4l2_set_format(video, fmt);
    }

    /* Buffers & streaming */
    case VIDIOC_REQBUFS:
    {
        struct v4l2_requestbuffers *rb = arg;

        if (rb->type != video->queue.type ||
            rb->memory != V4L2_MEMORY_MMAP)
            return -EINVAL;

        ret = uvc_alloc_buffers(&video->queue, rb->count,
                    video->imagesize);
        if (ret < 0)
            return ret;

        rb->count = ret;
        ret = 0;
        break;
    }

    case VIDIOC_QUERYBUF:
    {
        struct v4l2_buffer *buf = arg;

        if (buf->type != video->queue.type)
            return -EINVAL;

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

    case VIDIOC_QBUF:
        if ((ret = uvc_queue_buffer(&video->queue, arg)) < 0)
            return ret;

        return uvc_video_pump(video);

    case VIDIOC_DQBUF:
        return uvc_dequeue_buffer(&video->queue, arg,
            file->f_flags & O_NONBLOCK);

    case VIDIOC_STREAMON:
    {
        int *type = arg;

        if (*type != video->queue.type)
            return -EINVAL;

        return uvc_video_enable(video, 1);
    }

    case VIDIOC_STREAMOFF:
    {
        int *type = arg;

        if (*type != video->queue.type)
            return -EINVAL;

        return uvc_video_enable(video, 0);
    }

    /* Events */
        case VIDIOC_DQEVENT:
    {
        struct v4l2_event *event = arg;

        ret = v4l2_event_dequeue(&handle->vfh, event,
                     file->f_flags & O_NONBLOCK);
        if (ret == 0 && event->type == UVC_EVENT_SETUP) {
            struct uvc_event *uvc_event = (void *)&event->u.data;

            /* Tell the complete callback to generate an event for
             * the next request that will be enqueued by
             * uvc_event_write.
             */
            uvc->event_setup_out =
                !(uvc_event->req.bRequestType & USB_DIR_IN);
            uvc->event_length = uvc_event->req.wLength;
        }

        return ret;
    }

    case VIDIOC_SUBSCRIBE_EVENT:
    {
        struct v4l2_event_subscription *sub = arg;

        if (sub->type < UVC_EVENT_FIRST || sub->type > UVC_EVENT_LAST)
            return -EINVAL;

        return v4l2_event_subscribe(&handle->vfh, arg, 2, NULL);
    }

    case VIDIOC_UNSUBSCRIBE_EVENT:
        return v4l2_event_unsubscribe(&handle->vfh, arg);

    case UVCIOC_SEND_RESPONSE:
        ret = uvc_send_response(uvc, arg);
        break;

    default:
        return -ENOIOCTLCMD;
    }

    return ret;
}

static long
uvc_v4l2_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    return video_usercopy(file, cmd, arg, uvc_v4l2_do_ioctl);
}

static int
uvc_v4l2_mmap(struct file *file, struct vm_area_struct *vma)
{
    struct video_device *vdev = video_devdata(file);
    struct uvc_device *uvc = video_get_drvdata(vdev);

    return uvc_queue_mmap(&uvc->video.queue, vma);
}

static unsigned int
uvc_v4l2_poll(struct file *file, poll_table *wait)
{
    struct video_device *vdev = video_devdata(file);
    struct uvc_device *uvc = video_get_drvdata(vdev);
    struct uvc_file_handle *handle = to_uvc_file_handle(file->private_data);
    unsigned int mask = 0;

    poll_wait(file, &handle->vfh.wait, wait);
    if (v4l2_event_pending(&handle->vfh))
        mask |= POLLPRI;

    mask |= uvc_queue_poll(&uvc->video.queue, file, wait);

    return mask;
}

static struct v4l2_file_operations uvc_v4l2_fops = {
    .owner      = THIS_MODULE,
    .open       = uvc_v4l2_open,
    .release    = uvc_v4l2_release,
    .ioctl      = uvc_v4l2_ioctl,
    .mmap       = uvc_v4l2_mmap,
    .poll       = uvc_v4l2_poll,
};