f_uvc.c

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/*
 *  uvc_gadget.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/fs.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
#include <linux/usb/video.h>
#include <linux/vmalloc.h>
#include <linux/wait.h>

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

#include "uvc.h"

unsigned int uvc_gadget_trace_param;

/*-------------------------------------------------------------------------*/

/* module parameters specific to the Video streaming endpoint */
static unsigned streaming_interval = 1;
module_param(streaming_interval, uint, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(streaming_interval, "1 - 16");

static unsigned streaming_maxpacket = 1024;
module_param(streaming_maxpacket, uint, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(streaming_maxpacket, "0 - 1023 (fs), 0 - 1024 (hs/ss)");

static unsigned streaming_mult;
module_param(streaming_mult, uint, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(streaming_mult, "0 - 2 (hs/ss only)");

static unsigned streaming_maxburst;
module_param(streaming_maxburst, uint, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(streaming_maxburst, "0 - 15 (ss only)");

/* --------------------------------------------------------------------------
 * Function descriptors
 */

/* string IDs are assigned dynamically */

#define UVC_STRING_ASSOCIATION_IDX      0
#define UVC_STRING_CONTROL_IDX          1
#define UVC_STRING_STREAMING_IDX        2

static struct usb_string uvc_en_us_strings[] = {
    [UVC_STRING_ASSOCIATION_IDX].s = "UVC Camera",
    [UVC_STRING_CONTROL_IDX].s = "Video Control",
    [UVC_STRING_STREAMING_IDX].s = "Video Streaming",
    {  }
};

static struct usb_gadget_strings uvc_stringtab = {
    .language = 0x0409, /* en-us */
    .strings = uvc_en_us_strings,
};

static struct usb_gadget_strings *uvc_function_strings[] = {
    &uvc_stringtab,
    NULL,
};

#define UVC_INTF_VIDEO_CONTROL          0
#define UVC_INTF_VIDEO_STREAMING        1

#define STATUS_BYTECOUNT            16  /* 16 bytes status */

static struct usb_interface_assoc_descriptor uvc_iad __initdata = {
    .bLength        = sizeof(uvc_iad),
    .bDescriptorType    = USB_DT_INTERFACE_ASSOCIATION,
    .bFirstInterface    = 0,
    .bInterfaceCount    = 2,
    .bFunctionClass     = USB_CLASS_VIDEO,
    .bFunctionSubClass  = UVC_SC_VIDEO_INTERFACE_COLLECTION,
    .bFunctionProtocol  = 0x00,
    .iFunction      = 0,
};

static struct usb_interface_descriptor uvc_control_intf __initdata = {
    .bLength        = USB_DT_INTERFACE_SIZE,
    .bDescriptorType    = USB_DT_INTERFACE,
    .bInterfaceNumber   = UVC_INTF_VIDEO_CONTROL,
    .bAlternateSetting  = 0,
    .bNumEndpoints      = 1,
    .bInterfaceClass    = USB_CLASS_VIDEO,
    .bInterfaceSubClass = UVC_SC_VIDEOCONTROL,
    .bInterfaceProtocol = 0x00,
    .iInterface     = 0,
};

static struct usb_endpoint_descriptor uvc_fs_control_ep __initdata = {
    .bLength        = USB_DT_ENDPOINT_SIZE,
    .bDescriptorType    = USB_DT_ENDPOINT,
    .bEndpointAddress   = USB_DIR_IN,
    .bmAttributes       = USB_ENDPOINT_XFER_INT,
    .wMaxPacketSize     = cpu_to_le16(STATUS_BYTECOUNT),
    .bInterval      = 8,
};

static struct uvc_control_endpoint_descriptor uvc_control_cs_ep __initdata = {
    .bLength        = UVC_DT_CONTROL_ENDPOINT_SIZE,
    .bDescriptorType    = USB_DT_CS_ENDPOINT,
    .bDescriptorSubType = UVC_EP_INTERRUPT,
    .wMaxTransferSize   = cpu_to_le16(STATUS_BYTECOUNT),
};

static struct usb_interface_descriptor uvc_streaming_intf_alt0 __initdata = {
    .bLength        = USB_DT_INTERFACE_SIZE,
    .bDescriptorType    = USB_DT_INTERFACE,
    .bInterfaceNumber   = UVC_INTF_VIDEO_STREAMING,
    .bAlternateSetting  = 0,
    .bNumEndpoints      = 0,
    .bInterfaceClass    = USB_CLASS_VIDEO,
    .bInterfaceSubClass = UVC_SC_VIDEOSTREAMING,
    .bInterfaceProtocol = 0x00,
    .iInterface     = 0,
};

static struct usb_interface_descriptor uvc_streaming_intf_alt1 __initdata = {
    .bLength        = USB_DT_INTERFACE_SIZE,
    .bDescriptorType    = USB_DT_INTERFACE,
    .bInterfaceNumber   = UVC_INTF_VIDEO_STREAMING,
    .bAlternateSetting  = 1,
    .bNumEndpoints      = 1,
    .bInterfaceClass    = USB_CLASS_VIDEO,
    .bInterfaceSubClass = UVC_SC_VIDEOSTREAMING,
    .bInterfaceProtocol = 0x00,
    .iInterface     = 0,
};

static struct usb_endpoint_descriptor uvc_fs_streaming_ep = {
    .bLength        = USB_DT_ENDPOINT_SIZE,
    .bDescriptorType    = USB_DT_ENDPOINT,
    .bEndpointAddress   = USB_DIR_IN,
    .bmAttributes       = USB_ENDPOINT_XFER_ISOC,
    .wMaxPacketSize     = cpu_to_le16(512),
    .bInterval      = 1,
};

static struct usb_endpoint_descriptor uvc_hs_streaming_ep = {
    .bLength        = USB_DT_ENDPOINT_SIZE,
    .bDescriptorType    = USB_DT_ENDPOINT,
    .bEndpointAddress   = USB_DIR_IN,
    .bmAttributes       = USB_ENDPOINT_XFER_ISOC,
    .wMaxPacketSize     = cpu_to_le16(1024),
    .bInterval      = 1,
};

/* super speed support */
static struct usb_endpoint_descriptor uvc_ss_control_ep __initdata = {
    .bLength =      USB_DT_ENDPOINT_SIZE,
    .bDescriptorType =  USB_DT_ENDPOINT,

    .bEndpointAddress = USB_DIR_IN,
    .bmAttributes =     USB_ENDPOINT_XFER_INT,
    .wMaxPacketSize =   cpu_to_le16(STATUS_BYTECOUNT),
    .bInterval =        8,
};

static struct usb_ss_ep_comp_descriptor uvc_ss_control_comp __initdata = {
    .bLength =      sizeof uvc_ss_control_comp,
    .bDescriptorType =  USB_DT_SS_ENDPOINT_COMP,

    /* the following 3 values can be tweaked if necessary */
    /* .bMaxBurst =     0, */
    /* .bmAttributes =  0, */
    .wBytesPerInterval =    cpu_to_le16(STATUS_BYTECOUNT),
};

static struct usb_endpoint_descriptor uvc_ss_streaming_ep __initdata = {
    .bLength =      USB_DT_ENDPOINT_SIZE,
    .bDescriptorType =  USB_DT_ENDPOINT,

    .bEndpointAddress = USB_DIR_IN,
    .bmAttributes =     USB_ENDPOINT_XFER_ISOC,
    .wMaxPacketSize =   cpu_to_le16(1024),
    .bInterval =        4,
};

static struct usb_ss_ep_comp_descriptor uvc_ss_streaming_comp = {
    .bLength =      sizeof uvc_ss_streaming_comp,
    .bDescriptorType =  USB_DT_SS_ENDPOINT_COMP,

    /* the following 3 values can be tweaked if necessary */
    .bMaxBurst =        0,
    .bmAttributes = 0,
    .wBytesPerInterval =    cpu_to_le16(1024),
};

static const struct usb_descriptor_header * const uvc_fs_streaming[] = {
    (struct usb_descriptor_header *) &uvc_streaming_intf_alt1,
    (struct usb_descriptor_header *) &uvc_fs_streaming_ep,
    NULL,
};

static const struct usb_descriptor_header * const uvc_hs_streaming[] = {
    (struct usb_descriptor_header *) &uvc_streaming_intf_alt1,
    (struct usb_descriptor_header *) &uvc_hs_streaming_ep,
    NULL,
};

static const struct usb_descriptor_header * const uvc_ss_streaming[] = {
    (struct usb_descriptor_header *) &uvc_streaming_intf_alt1,
    (struct usb_descriptor_header *) &uvc_ss_streaming_ep,
    (struct usb_descriptor_header *) &uvc_ss_streaming_comp,
    NULL,
};

/* --------------------------------------------------------------------------
 * Control requests
 */

static void
uvc_function_ep0_complete(struct usb_ep *ep, struct usb_request *req)
{
    struct uvc_device *uvc = req->context;
    struct v4l2_event v4l2_event;
    struct uvc_event *uvc_event = (void *)&v4l2_event.u.data;

    if (uvc->event_setup_out) {
        uvc->event_setup_out = 0;

        memset(&v4l2_event, 0, sizeof(v4l2_event));
        v4l2_event.type = UVC_EVENT_DATA;
        uvc_event->data.length = req->actual;
        memcpy(&uvc_event->data.data, req->buf, req->actual);
        v4l2_event_queue(uvc->vdev, &v4l2_event);
    }
}

static int
uvc_function_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
{
    struct uvc_device *uvc = to_uvc(f);
    struct v4l2_event v4l2_event;
    struct uvc_event *uvc_event = (void *)&v4l2_event.u.data;

    /* printk(KERN_INFO "setup request %02x %02x value %04x index %04x %04x\n",
     *  ctrl->bRequestType, ctrl->bRequest, le16_to_cpu(ctrl->wValue),
     *  le16_to_cpu(ctrl->wIndex), le16_to_cpu(ctrl->wLength));
     */

    if ((ctrl->bRequestType & USB_TYPE_MASK) != USB_TYPE_CLASS) {
        INFO(f->config->cdev, "invalid request type\n");
        return -EINVAL;
    }

    /* Stall too big requests. */
    if (le16_to_cpu(ctrl->wLength) > UVC_MAX_REQUEST_SIZE)
        return -EINVAL;

    memset(&v4l2_event, 0, sizeof(v4l2_event));
    v4l2_event.type = UVC_EVENT_SETUP;
    memcpy(&uvc_event->req, ctrl, sizeof(uvc_event->req));
    v4l2_event_queue(uvc->vdev, &v4l2_event);

    return 0;
}

static int
uvc_function_get_alt(struct usb_function *f, unsigned interface)
{
    struct uvc_device *uvc = to_uvc(f);

    INFO(f->config->cdev, "uvc_function_get_alt(%u)\n", interface);

    if (interface == uvc->control_intf)
        return 0;
    else if (interface != uvc->streaming_intf)
        return -EINVAL;
    else
        return uvc->state == UVC_STATE_STREAMING ? 1 : 0;
}

static int
uvc_function_set_alt(struct usb_function *f, unsigned interface, unsigned alt)
{
    struct uvc_device *uvc = to_uvc(f);
    struct v4l2_event v4l2_event;
    struct uvc_event *uvc_event = (void *)&v4l2_event.u.data;
    int ret;

    INFO(f->config->cdev, "uvc_function_set_alt(%u, %u)\n", interface, alt);

    if (interface == uvc->control_intf) {
        if (alt)
            return -EINVAL;

        if (uvc->state == UVC_STATE_DISCONNECTED) {
            memset(&v4l2_event, 0, sizeof(v4l2_event));
            v4l2_event.type = UVC_EVENT_CONNECT;
            uvc_event->speed = f->config->cdev->gadget->speed;
            v4l2_event_queue(uvc->vdev, &v4l2_event);

            uvc->state = UVC_STATE_CONNECTED;
        }

        return 0;
    }

    if (interface != uvc->streaming_intf)
        return -EINVAL;

    /* TODO
    if (usb_endpoint_xfer_bulk(&uvc->desc.vs_ep))
        return alt ? -EINVAL : 0;
    */

    switch (alt) {
    case 0:
        if (uvc->state != UVC_STATE_STREAMING)
            return 0;

        if (uvc->video.ep)
            usb_ep_disable(uvc->video.ep);

        memset(&v4l2_event, 0, sizeof(v4l2_event));
        v4l2_event.type = UVC_EVENT_STREAMOFF;
        v4l2_event_queue(uvc->vdev, &v4l2_event);

        uvc->state = UVC_STATE_CONNECTED;
        break;

    case 1:
        if (uvc->state != UVC_STATE_CONNECTED)
            return 0;

        if (uvc->video.ep) {
            ret = config_ep_by_speed(f->config->cdev->gadget,
                    &(uvc->func), uvc->video.ep);
            if (ret)
                return ret;
            usb_ep_enable(uvc->video.ep);
        }

        memset(&v4l2_event, 0, sizeof(v4l2_event));
        v4l2_event.type = UVC_EVENT_STREAMON;
        v4l2_event_queue(uvc->vdev, &v4l2_event);

        uvc->state = UVC_STATE_STREAMING;
        break;

    default:
        return -EINVAL;
    }

    return 0;
}

static void
uvc_function_disable(struct usb_function *f)
{
    struct uvc_device *uvc = to_uvc(f);
    struct v4l2_event v4l2_event;

    INFO(f->config->cdev, "uvc_function_disable\n");

    memset(&v4l2_event, 0, sizeof(v4l2_event));
    v4l2_event.type = UVC_EVENT_DISCONNECT;
    v4l2_event_queue(uvc->vdev, &v4l2_event);

    uvc->state = UVC_STATE_DISCONNECTED;
}

/* --------------------------------------------------------------------------
 * Connection / disconnection
 */

void
uvc_function_connect(struct uvc_device *uvc)
{
    struct usb_composite_dev *cdev = uvc->func.config->cdev;
    int ret;

    if ((ret = usb_function_activate(&uvc->func)) < 0)
        INFO(cdev, "UVC connect failed with %d\n", ret);
}

void
uvc_function_disconnect(struct uvc_device *uvc)
{
    struct usb_composite_dev *cdev = uvc->func.config->cdev;
    int ret;

    if ((ret = usb_function_deactivate(&uvc->func)) < 0)
        INFO(cdev, "UVC disconnect failed with %d\n", ret);
}

/* --------------------------------------------------------------------------
 * USB probe and disconnect
 */

static int
uvc_register_video(struct uvc_device *uvc)
{
    struct usb_composite_dev *cdev = uvc->func.config->cdev;
    struct video_device *video;

    /* TODO reference counting. */
    video = video_device_alloc();
    if (video == NULL)
        return -ENOMEM;

    video->parent = &cdev->gadget->dev;
    video->minor = -1;
    video->fops = &uvc_v4l2_fops;
    video->release = video_device_release;
    strncpy(video->name, cdev->gadget->name, sizeof(video->name));

    uvc->vdev = video;
    video_set_drvdata(video, uvc);

    return video_register_device(video, VFL_TYPE_GRABBER, -1);
}

#define UVC_COPY_DESCRIPTOR(mem, dst, desc) \
    do { \
        memcpy(mem, desc, (desc)->bLength); \
        *(dst)++ = mem; \
        mem += (desc)->bLength; \
    } while (0);

#define UVC_COPY_DESCRIPTORS(mem, dst, src) \
    do { \
        const struct usb_descriptor_header * const *__src; \
        for (__src = src; *__src; ++__src) { \
            memcpy(mem, *__src, (*__src)->bLength); \
            *dst++ = mem; \
            mem += (*__src)->bLength; \
        } \
    } while (0)

static struct usb_descriptor_header ** __init
uvc_copy_descriptors(struct uvc_device *uvc, enum usb_device_speed speed)
{
    struct uvc_input_header_descriptor *uvc_streaming_header;
    struct uvc_header_descriptor *uvc_control_header;
    const struct uvc_descriptor_header * const *uvc_control_desc;
    const struct uvc_descriptor_header * const *uvc_streaming_cls;
    const struct usb_descriptor_header * const *uvc_streaming_std;
    const struct usb_descriptor_header * const *src;
    static struct usb_endpoint_descriptor *uvc_control_ep;
    struct usb_descriptor_header **dst;
    struct usb_descriptor_header **hdr;
    unsigned int control_size;
    unsigned int streaming_size;
    unsigned int n_desc;
    unsigned int bytes;
    void *mem;

    switch (speed) {
    case USB_SPEED_SUPER:
        uvc_control_desc = uvc->desc.ss_control;
        uvc_streaming_cls = uvc->desc.ss_streaming;
        uvc_streaming_std = uvc_ss_streaming;
        uvc_control_ep = &uvc_ss_control_ep;
        break;

    case USB_SPEED_HIGH:
        uvc_control_desc = uvc->desc.fs_control;
        uvc_streaming_cls = uvc->desc.hs_streaming;
        uvc_streaming_std = uvc_hs_streaming;
        uvc_control_ep = &uvc_fs_control_ep;
        break;

    case USB_SPEED_FULL:
    default:
        uvc_control_desc = uvc->desc.fs_control;
        uvc_streaming_cls = uvc->desc.fs_streaming;
        uvc_streaming_std = uvc_fs_streaming;
        uvc_control_ep = &uvc_fs_control_ep;
        break;
    }

    /* Descriptors layout
     *
     * uvc_iad
     * uvc_control_intf
     * Class-specific UVC control descriptors
     * uvc_control_ep
     * uvc_control_cs_ep
     * uvc_streaming_intf_alt0
     * Class-specific UVC streaming descriptors
     * uvc_{fs|hs}_streaming
     */

    /* Count descriptors and compute their size. */
    control_size = 0;
    streaming_size = 0;
    bytes = uvc_iad.bLength + uvc_control_intf.bLength
          + uvc_control_ep->bLength + uvc_control_cs_ep.bLength
          + uvc_streaming_intf_alt0.bLength;

    if (speed == USB_SPEED_SUPER) {
        bytes += uvc_ss_control_comp.bLength;
        n_desc = 6;
    } else {
        n_desc = 5;
    }

    for (src = (const struct usb_descriptor_header **)uvc_control_desc;
            *src; ++src) {
        control_size += (*src)->bLength;
        bytes += (*src)->bLength;
        n_desc++;
    }
    for (src = (const struct usb_descriptor_header **)uvc_streaming_cls;
            *src; ++src) {
        streaming_size += (*src)->bLength;
        bytes += (*src)->bLength;
        n_desc++;
    }
    for (src = uvc_streaming_std; *src; ++src) {
        bytes += (*src)->bLength;
        n_desc++;
    }

    mem = kmalloc((n_desc + 1) * sizeof(*src) + bytes, GFP_KERNEL);
    if (mem == NULL)
        return NULL;

    hdr = mem;
    dst = mem;
    mem += (n_desc + 1) * sizeof(*src);

    /* Copy the descriptors. */
    UVC_COPY_DESCRIPTOR(mem, dst, &uvc_iad);
    UVC_COPY_DESCRIPTOR(mem, dst, &uvc_control_intf);

    uvc_control_header = mem;
    UVC_COPY_DESCRIPTORS(mem, dst,
        (const struct usb_descriptor_header **)uvc_control_desc);
    uvc_control_header->wTotalLength = cpu_to_le16(control_size);
    uvc_control_header->bInCollection = 1;
    uvc_control_header->baInterfaceNr[0] = uvc->streaming_intf;

    UVC_COPY_DESCRIPTOR(mem, dst, uvc_control_ep);
    if (speed == USB_SPEED_SUPER)
        UVC_COPY_DESCRIPTOR(mem, dst, &uvc_ss_control_comp);

    UVC_COPY_DESCRIPTOR(mem, dst, &uvc_control_cs_ep);
    UVC_COPY_DESCRIPTOR(mem, dst, &uvc_streaming_intf_alt0);

    uvc_streaming_header = mem;
    UVC_COPY_DESCRIPTORS(mem, dst,
        (const struct usb_descriptor_header**)uvc_streaming_cls);
    uvc_streaming_header->wTotalLength = cpu_to_le16(streaming_size);
    uvc_streaming_header->bEndpointAddress =
        uvc_fs_streaming_ep.bEndpointAddress;

    UVC_COPY_DESCRIPTORS(mem, dst, uvc_streaming_std);

    *dst = NULL;
    return hdr;
}

static void
uvc_function_unbind(struct usb_configuration *c, struct usb_function *f)
{
    struct usb_composite_dev *cdev = c->cdev;
    struct uvc_device *uvc = to_uvc(f);

    INFO(cdev, "uvc_function_unbind\n");

    if (uvc->vdev) {
        if (uvc->vdev->minor == -1)
            video_device_release(uvc->vdev);
        else
            video_unregister_device(uvc->vdev);
        uvc->vdev = NULL;
    }

    if (uvc->control_ep)
        uvc->control_ep->driver_data = NULL;
    if (uvc->video.ep)
        uvc->video.ep->driver_data = NULL;

    if (uvc->control_req) {
        usb_ep_free_request(cdev->gadget->ep0, uvc->control_req);
        kfree(uvc->control_buf);
    }

    kfree(f->descriptors);
    kfree(f->hs_descriptors);
    kfree(f->ss_descriptors);

    kfree(uvc);
}

static int __init
uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
{
    struct usb_composite_dev *cdev = c->cdev;
    struct uvc_device *uvc = to_uvc(f);
    struct usb_ep *ep;
    int ret = -EINVAL;

    INFO(cdev, "uvc_function_bind\n");

    /* sanity check the streaming endpoint module parameters */
    if (streaming_interval < 1)
        streaming_interval = 1;
    if (streaming_interval > 16)
        streaming_interval = 16;
    if (streaming_mult > 2)
        streaming_mult = 2;
    if (streaming_maxburst > 15)
        streaming_maxburst = 15;

    /*
     * fill in the FS video streaming specific descriptors from the
     * module parameters
     */
    uvc_fs_streaming_ep.wMaxPacketSize = streaming_maxpacket > 1023 ?
                        1023 : streaming_maxpacket;
    uvc_fs_streaming_ep.bInterval = streaming_interval;

    /* Allocate endpoints. */
    ep = usb_ep_autoconfig(cdev->gadget, &uvc_fs_control_ep);
    if (!ep) {
        INFO(cdev, "Unable to allocate control EP\n");
        goto error;
    }
    uvc->control_ep = ep;
    ep->driver_data = uvc;

    ep = usb_ep_autoconfig(cdev->gadget, &uvc_fs_streaming_ep);
    if (!ep) {
        INFO(cdev, "Unable to allocate streaming EP\n");
        goto error;
    }
    uvc->video.ep = ep;
    ep->driver_data = uvc;

    /* Allocate interface IDs. */
    if ((ret = usb_interface_id(c, f)) < 0)
        goto error;
    uvc_iad.bFirstInterface = ret;
    uvc_control_intf.bInterfaceNumber = ret;
    uvc->control_intf = ret;

    if ((ret = usb_interface_id(c, f)) < 0)
        goto error;
    uvc_streaming_intf_alt0.bInterfaceNumber = ret;
    uvc_streaming_intf_alt1.bInterfaceNumber = ret;
    uvc->streaming_intf = ret;

    /* sanity check the streaming endpoint module parameters */
    if (streaming_maxpacket > 1024)
        streaming_maxpacket = 1024;

    /* Copy descriptors for FS. */
    f->descriptors = uvc_copy_descriptors(uvc, USB_SPEED_FULL);

    /* support high speed hardware */
    if (gadget_is_dualspeed(cdev->gadget)) {
        /*
         * Fill in the HS descriptors from the module parameters for the
         * Video Streaming endpoint.
         * NOTE: We assume that the user knows what they are doing and
         * won't give parameters that their UDC doesn't support.
         */
        uvc_hs_streaming_ep.wMaxPacketSize = streaming_maxpacket;
        uvc_hs_streaming_ep.wMaxPacketSize |= streaming_mult << 11;
        uvc_hs_streaming_ep.bInterval = streaming_interval;
        uvc_hs_streaming_ep.bEndpointAddress =
                uvc_fs_streaming_ep.bEndpointAddress;

        /* Copy descriptors. */
        f->hs_descriptors = uvc_copy_descriptors(uvc, USB_SPEED_HIGH);
    }

    /* support super speed hardware */
    if (gadget_is_superspeed(c->cdev->gadget)) {
        /*
         * Fill in the SS descriptors from the module parameters for the
         * Video Streaming endpoint.
         * NOTE: We assume that the user knows what they are doing and
         * won't give parameters that their UDC doesn't support.
         */
        uvc_ss_streaming_ep.wMaxPacketSize = streaming_maxpacket;
        uvc_ss_streaming_ep.bInterval = streaming_interval;
        uvc_ss_streaming_comp.bmAttributes = streaming_mult;
        uvc_ss_streaming_comp.bMaxBurst = streaming_maxburst;
        uvc_ss_streaming_comp.wBytesPerInterval =
            streaming_maxpacket * (streaming_mult + 1) *
            (streaming_maxburst + 1);
        uvc_ss_streaming_ep.bEndpointAddress =
                uvc_fs_streaming_ep.bEndpointAddress;

        /* Copy descriptors. */
        f->ss_descriptors = uvc_copy_descriptors(uvc, USB_SPEED_SUPER);
    }

    /* Preallocate control endpoint request. */
    uvc->control_req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
    uvc->control_buf = kmalloc(UVC_MAX_REQUEST_SIZE, GFP_KERNEL);
    if (uvc->control_req == NULL || uvc->control_buf == NULL) {
        ret = -ENOMEM;
        goto error;
    }

    uvc->control_req->buf = uvc->control_buf;
    uvc->control_req->complete = uvc_function_ep0_complete;
    uvc->control_req->context = uvc;

    /* Avoid letting this gadget enumerate until the userspace server is
     * active.
     */
    if ((ret = usb_function_deactivate(f)) < 0)
        goto error;

    /* Initialise video. */
    ret = uvc_video_init(&uvc->video);
    if (ret < 0)
        goto error;

    /* Register a V4L2 device. */
    ret = uvc_register_video(uvc);
    if (ret < 0) {
        printk(KERN_INFO "Unable to register video device\n");
        goto error;
    }

    return 0;

error:
    uvc_function_unbind(c, f);
    return ret;
}

/* --------------------------------------------------------------------------
 * USB gadget function
 */

int __init
uvc_bind_config(struct usb_configuration *c,
        const struct uvc_descriptor_header * const *fs_control,
        const struct uvc_descriptor_header * const *ss_control,
        const struct uvc_descriptor_header * const *fs_streaming,
        const struct uvc_descriptor_header * const *hs_streaming,
        const struct uvc_descriptor_header * const *ss_streaming)
{
    struct uvc_device *uvc;
    int ret = 0;

    /* TODO Check if the USB device controller supports the required
     * features.
     */
    if (!gadget_is_dualspeed(c->cdev->gadget))
        return -EINVAL;

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

    uvc->state = UVC_STATE_DISCONNECTED;

    /* Validate the descriptors. */
    if (fs_control == NULL || fs_control[0] == NULL ||
        fs_control[0]->bDescriptorSubType != UVC_VC_HEADER)
        goto error;

    if (ss_control == NULL || ss_control[0] == NULL ||
        ss_control[0]->bDescriptorSubType != UVC_VC_HEADER)
        goto error;

    if (fs_streaming == NULL || fs_streaming[0] == NULL ||
        fs_streaming[0]->bDescriptorSubType != UVC_VS_INPUT_HEADER)
        goto error;

    if (hs_streaming == NULL || hs_streaming[0] == NULL ||
        hs_streaming[0]->bDescriptorSubType != UVC_VS_INPUT_HEADER)
        goto error;

    if (ss_streaming == NULL || ss_streaming[0] == NULL ||
        ss_streaming[0]->bDescriptorSubType != UVC_VS_INPUT_HEADER)
        goto error;

    uvc->desc.fs_control = fs_control;
    uvc->desc.ss_control = ss_control;
    uvc->desc.fs_streaming = fs_streaming;
    uvc->desc.hs_streaming = hs_streaming;
    uvc->desc.ss_streaming = ss_streaming;

    /* maybe allocate device-global string IDs, and patch descriptors */
    if (uvc_en_us_strings[UVC_STRING_ASSOCIATION_IDX].id == 0) {
        /* Allocate string descriptor numbers. */
        ret = usb_string_id(c->cdev);
        if (ret < 0)
            goto error;
        uvc_en_us_strings[UVC_STRING_ASSOCIATION_IDX].id = ret;
        uvc_iad.iFunction = ret;

        ret = usb_string_id(c->cdev);
        if (ret < 0)
            goto error;
        uvc_en_us_strings[UVC_STRING_CONTROL_IDX].id = ret;
        uvc_control_intf.iInterface = ret;

        ret = usb_string_id(c->cdev);
        if (ret < 0)
            goto error;
        uvc_en_us_strings[UVC_STRING_STREAMING_IDX].id = ret;
        uvc_streaming_intf_alt0.iInterface = ret;
        uvc_streaming_intf_alt1.iInterface = ret;
    }

    /* Register the function. */
    uvc->func.name = "uvc";
    uvc->func.strings = uvc_function_strings;
    uvc->func.bind = uvc_function_bind;
    uvc->func.unbind = uvc_function_unbind;
    uvc->func.get_alt = uvc_function_get_alt;
    uvc->func.set_alt = uvc_function_set_alt;
    uvc->func.disable = uvc_function_disable;
    uvc->func.setup = uvc_function_setup;

    ret = usb_add_function(c, &uvc->func);
    if (ret)
        kfree(uvc);

    return ret;

error:
    kfree(uvc);
    return ret;
}

module_param_named(trace, uvc_gadget_trace_param, uint, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(trace, "Trace level bitmask");