Initial import

1 files changed, 958 insertions, 0 deletions

diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
new file mode 100644
index 000000000..cf0df8fbb
--- /dev/null
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -0,0 +1,958 @@
+/*
+ *	uvc_gadget.c  --  USB Video Class Gadget driver
+ *
+ *	Copyright (C) 2009-2010
+ *	    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/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/string.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 "u_uvc.h"
+#include "uvc.h"
+#include "uvc_configfs.h"
+#include "uvc_v4l2.h"
+#include "uvc_video.h"
+
+unsigned int uvc_gadget_trace_param;
+
+/* --------------------------------------------------------------------------
+ * Function descriptors
+ */
+
+/* string IDs are assigned dynamically */
+
+#define UVC_STRING_CONTROL_IDX			0
+#define UVC_STRING_STREAMING_IDX		1
+
+static struct usb_string uvc_en_us_strings[] = {
+	[UVC_STRING_CONTROL_IDX].s = "UVC Camera",
+	[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 UVC_STATUS_MAX_PACKET_SIZE		16	/* 16 bytes status */
+
+static struct usb_interface_assoc_descriptor uvc_iad = {
+	.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 = {
+	.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_control_ep = {
+	.bLength		= USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType	= USB_DT_ENDPOINT,
+	.bEndpointAddress	= USB_DIR_IN,
+	.bmAttributes		= USB_ENDPOINT_XFER_INT,
+	.wMaxPacketSize		= cpu_to_le16(UVC_STATUS_MAX_PACKET_SIZE),
+	.bInterval		= 8,
+};
+
+static struct usb_ss_ep_comp_descriptor uvc_ss_control_comp = {
+	.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(UVC_STATUS_MAX_PACKET_SIZE),
+};
+
+static struct uvc_control_endpoint_descriptor uvc_control_cs_ep = {
+	.bLength		= UVC_DT_CONTROL_ENDPOINT_SIZE,
+	.bDescriptorType	= USB_DT_CS_ENDPOINT,
+	.bDescriptorSubType	= UVC_EP_INTERRUPT,
+	.wMaxTransferSize	= cpu_to_le16(UVC_STATUS_MAX_PACKET_SIZE),
+};
+
+static struct usb_interface_descriptor uvc_streaming_intf_alt0 = {
+	.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 = {
+	.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_SYNC_ASYNC
+				| USB_ENDPOINT_XFER_ISOC,
+	/* The wMaxPacketSize and bInterval values will be initialized from
+	 * module parameters.
+	 */
+};
+
+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_SYNC_ASYNC
+				| USB_ENDPOINT_XFER_ISOC,
+	/* The wMaxPacketSize and bInterval values will be initialized from
+	 * module parameters.
+	 */
+};
+
+static struct usb_endpoint_descriptor uvc_ss_streaming_ep = {
+	.bLength		= USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType	= USB_DT_ENDPOINT,
+
+	.bEndpointAddress	= USB_DIR_IN,
+	.bmAttributes		= USB_ENDPOINT_SYNC_ASYNC
+				| USB_ENDPOINT_XFER_ISOC,
+	/* The wMaxPacketSize and bInterval values will be initialized from
+	 * module parameters.
+	 */
+};
+
+static struct usb_ss_ep_comp_descriptor uvc_ss_streaming_comp = {
+	.bLength		= sizeof(uvc_ss_streaming_comp),
+	.bDescriptorType	= USB_DT_SS_ENDPOINT_COMP,
+	/* The bMaxBurst, bmAttributes and wBytesPerInterval values will be
+	 * initialized from module parameters.
+	 */
+};
+
+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,
+};
+
+void uvc_set_trace_param(unsigned int trace)
+{
+	uvc_gadget_trace_param = trace;
+}
+EXPORT_SYMBOL(uvc_set_trace_param);
+
+/* --------------------------------------------------------------------------
+ * 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;
+
+	/* Tell the complete callback to generate an event for the next request
+	 * that will be enqueued by UVCIOC_SEND_RESPONSE.
+	 */
+	uvc->event_setup_out = !(ctrl->bRequestType & USB_DIR_IN);
+	uvc->event_length = le16_to_cpu(ctrl->wLength);
+
+	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;
+}
+
+void uvc_function_setup_continue(struct uvc_device *uvc)
+{
+	struct usb_composite_dev *cdev = uvc->func.config->cdev;
+
+	usb_composite_setup_continue(cdev);
+}
+
+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->video.ep->driver_data ? 1 : 0;
+}
+
+static int
+uvc_function_set_alt(struct usb_function *f, unsigned interface, unsigned alt)
+{
+	struct uvc_device *uvc = to_uvc(f);
+	struct usb_composite_dev *cdev = f->config->cdev;
+	struct v4l2_event v4l2_event;
+	struct uvc_event *uvc_event = (void *)&v4l2_event.u.data;
+	int ret;
+
+	INFO(cdev, "uvc_function_set_alt(%u, %u)\n", interface, alt);
+
+	if (interface == uvc->control_intf) {
+		if (alt)
+			return -EINVAL;
+
+		if (uvc->control_ep->driver_data) {
+			INFO(cdev, "reset UVC Control\n");
+			usb_ep_disable(uvc->control_ep);
+			uvc->control_ep->driver_data = NULL;
+		}
+
+		if (!uvc->control_ep->desc)
+			if (config_ep_by_speed(cdev->gadget, f, uvc->control_ep))
+				return -EINVAL;
+
+		usb_ep_enable(uvc->control_ep);
+		uvc->control_ep->driver_data = uvc;
+
+		if (uvc->state == UVC_STATE_DISCONNECTED) {
+			memset(&v4l2_event, 0, sizeof(v4l2_event));
+			v4l2_event.type = UVC_EVENT_CONNECT;
+			uvc_event->speed = 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);
+			uvc->video.ep->driver_data = NULL;
+		}
+
+		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;
+		return 0;
+
+	case 1:
+		if (uvc->state != UVC_STATE_CONNECTED)
+			return 0;
+
+		if (!uvc->video.ep)
+			return -EINVAL;
+
+		if (uvc->video.ep->driver_data) {
+			INFO(cdev, "reset UVC\n");
+			usb_ep_disable(uvc->video.ep);
+			uvc->video.ep->driver_data = NULL;
+		}
+
+		ret = config_ep_by_speed(f->config->cdev->gadget,
+				&(uvc->func), uvc->video.ep);
+		if (ret)
+			return ret;
+		usb_ep_enable(uvc->video.ep);
+		uvc->video.ep->driver_data = uvc;
+
+		memset(&v4l2_event, 0, sizeof(v4l2_event));
+		v4l2_event.type = UVC_EVENT_STREAMON;
+		v4l2_event_queue(&uvc->vdev, &v4l2_event);
+		return USB_GADGET_DELAYED_STATUS;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+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;
+
+	if (uvc->video.ep->driver_data) {
+		usb_ep_disable(uvc->video.ep);
+		uvc->video.ep->driver_data = NULL;
+	}
+
+	if (uvc->control_ep->driver_data) {
+		usb_ep_disable(uvc->control_ep);
+		uvc->control_ep->driver_data = NULL;
+	}
+}
+
+/* --------------------------------------------------------------------------
+ * 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;
+
+	/* TODO reference counting. */
+	uvc->vdev.v4l2_dev = &uvc->v4l2_dev;
+	uvc->vdev.fops = &uvc_v4l2_fops;
+	uvc->vdev.ioctl_ops = &uvc_v4l2_ioctl_ops;
+	uvc->vdev.release = video_device_release_empty;
+	uvc->vdev.vfl_dir = VFL_DIR_TX;
+	uvc->vdev.lock = &uvc->video.mutex;
+	strlcpy(uvc->vdev.name, cdev->gadget->name, sizeof(uvc->vdev.name));
+
+	video_set_drvdata(&uvc->vdev, uvc);
+
+	return video_register_device(&uvc->vdev, 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 **
+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;
+	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;
+		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;
+		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;
+		break;
+	}
+
+	if (!uvc_control_desc || !uvc_streaming_cls)
+		return ERR_PTR(-ENODEV);
+
+	/* Descriptors layout
+	 *
+	 * uvc_iad
+	 * uvc_control_intf
+	 * Class-specific UVC control descriptors
+	 * uvc_control_ep
+	 * uvc_control_cs_ep
+	 * uvc_ss_control_comp (for SS only)
+	 * 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->video.ep->address;
+
+	UVC_COPY_DESCRIPTORS(mem, dst, uvc_streaming_std);
+
+	*dst = NULL;
+	return hdr;
+}
+
+static int
+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_string *us;
+	unsigned int max_packet_mult;
+	unsigned int max_packet_size;
+	struct usb_ep *ep;
+	struct f_uvc_opts *opts;
+	int ret = -EINVAL;
+
+	INFO(cdev, "uvc_function_bind\n");
+
+	opts = fi_to_f_uvc_opts(f->fi);
+	/* Sanity check the streaming endpoint module parameters.
+	 */
+	opts->streaming_interval = clamp(opts->streaming_interval, 1U, 16U);
+	opts->streaming_maxpacket = clamp(opts->streaming_maxpacket, 1U, 3072U);
+	opts->streaming_maxburst = min(opts->streaming_maxburst, 15U);
+
+	/* Fill in the FS/HS/SS Video Streaming specific descriptors from the
+	 * module parameters.
+	 *
+	 * NOTE: We assume that the user knows what they are doing and won't
+	 * give parameters that their UDC doesn't support.
+	 */
+	if (opts->streaming_maxpacket <= 1024) {
+		max_packet_mult = 1;
+		max_packet_size = opts->streaming_maxpacket;
+	} else if (opts->streaming_maxpacket <= 2048) {
+		max_packet_mult = 2;
+		max_packet_size = opts->streaming_maxpacket / 2;
+	} else {
+		max_packet_mult = 3;
+		max_packet_size = opts->streaming_maxpacket / 3;
+	}
+
+	uvc_fs_streaming_ep.wMaxPacketSize =
+		cpu_to_le16(min(opts->streaming_maxpacket, 1023U));
+	uvc_fs_streaming_ep.bInterval = opts->streaming_interval;
+
+	uvc_hs_streaming_ep.wMaxPacketSize =
+		cpu_to_le16(max_packet_size | ((max_packet_mult - 1) << 11));
+	uvc_hs_streaming_ep.bInterval = opts->streaming_interval;
+
+	uvc_ss_streaming_ep.wMaxPacketSize = cpu_to_le16(max_packet_size);
+	uvc_ss_streaming_ep.bInterval = opts->streaming_interval;
+	uvc_ss_streaming_comp.bmAttributes = max_packet_mult - 1;
+	uvc_ss_streaming_comp.bMaxBurst = opts->streaming_maxburst;
+	uvc_ss_streaming_comp.wBytesPerInterval =
+		cpu_to_le16(max_packet_size * max_packet_mult *
+			    opts->streaming_maxburst);
+
+	/* Allocate endpoints. */
+	ep = usb_ep_autoconfig(cdev->gadget, &uvc_control_ep);
+	if (!ep) {
+		INFO(cdev, "Unable to allocate control EP\n");
+		goto error;
+	}
+	uvc->control_ep = ep;
+	ep->driver_data = uvc;
+
+	if (gadget_is_superspeed(c->cdev->gadget))
+		ep = usb_ep_autoconfig_ss(cdev->gadget, &uvc_ss_streaming_ep,
+					  &uvc_ss_streaming_comp);
+	else if (gadget_is_dualspeed(cdev->gadget))
+		ep = usb_ep_autoconfig(cdev->gadget, &uvc_hs_streaming_ep);
+	else
+		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;
+
+	uvc_fs_streaming_ep.bEndpointAddress = uvc->video.ep->address;
+	uvc_hs_streaming_ep.bEndpointAddress = uvc->video.ep->address;
+	uvc_ss_streaming_ep.bEndpointAddress = uvc->video.ep->address;
+
+	us = usb_gstrings_attach(cdev, uvc_function_strings,
+				 ARRAY_SIZE(uvc_en_us_strings));
+	if (IS_ERR(us)) {
+		ret = PTR_ERR(us);
+		goto error;
+	}
+	uvc_iad.iFunction = us[UVC_STRING_CONTROL_IDX].id;
+	uvc_control_intf.iInterface = us[UVC_STRING_CONTROL_IDX].id;
+	ret = us[UVC_STRING_STREAMING_IDX].id;
+	uvc_streaming_intf_alt0.iInterface = ret;
+	uvc_streaming_intf_alt1.iInterface = ret;
+
+	/* 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;
+
+	/* Copy descriptors */
+	f->fs_descriptors = uvc_copy_descriptors(uvc, USB_SPEED_FULL);
+	if (IS_ERR(f->fs_descriptors)) {
+		ret = PTR_ERR(f->fs_descriptors);
+		f->fs_descriptors = NULL;
+		goto error;
+	}
+	if (gadget_is_dualspeed(cdev->gadget)) {
+		f->hs_descriptors = uvc_copy_descriptors(uvc, USB_SPEED_HIGH);
+		if (IS_ERR(f->hs_descriptors)) {
+			ret = PTR_ERR(f->hs_descriptors);
+			f->hs_descriptors = NULL;
+			goto error;
+		}
+	}
+	if (gadget_is_superspeed(c->cdev->gadget)) {
+		f->ss_descriptors = uvc_copy_descriptors(uvc, USB_SPEED_SUPER);
+		if (IS_ERR(f->ss_descriptors)) {
+			ret = PTR_ERR(f->ss_descriptors);
+			f->ss_descriptors = NULL;
+			goto error;
+		}
+	}
+
+	/* 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;
+
+	if (v4l2_device_register(&cdev->gadget->dev, &uvc->v4l2_dev)) {
+		printk(KERN_INFO "v4l2_device_register failed\n");
+		goto error;
+	}
+
+	/* Initialise video. */
+	ret = uvcg_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:
+	v4l2_device_unregister(&uvc->v4l2_dev);
+
+	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);
+
+	usb_free_all_descriptors(f);
+	return ret;
+}
+
+/* --------------------------------------------------------------------------
+ * USB gadget function
+ */
+
+static void uvc_free_inst(struct usb_function_instance *f)
+{
+	struct f_uvc_opts *opts = fi_to_f_uvc_opts(f);
+
+	mutex_destroy(&opts->lock);
+	kfree(opts);
+}
+
+static struct usb_function_instance *uvc_alloc_inst(void)
+{
+	struct f_uvc_opts *opts;
+	struct uvc_camera_terminal_descriptor *cd;
+	struct uvc_processing_unit_descriptor *pd;
+	struct uvc_output_terminal_descriptor *od;
+	struct uvc_color_matching_descriptor *md;
+	struct uvc_descriptor_header **ctl_cls;
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return ERR_PTR(-ENOMEM);
+	opts->func_inst.free_func_inst = uvc_free_inst;
+	mutex_init(&opts->lock);
+
+	cd = &opts->uvc_camera_terminal;
+	cd->bLength			= UVC_DT_CAMERA_TERMINAL_SIZE(3);
+	cd->bDescriptorType		= USB_DT_CS_INTERFACE;
+	cd->bDescriptorSubType		= UVC_VC_INPUT_TERMINAL;
+	cd->bTerminalID			= 1;
+	cd->wTerminalType		= cpu_to_le16(0x0201);
+	cd->bAssocTerminal		= 0;
+	cd->iTerminal			= 0;
+	cd->wObjectiveFocalLengthMin	= cpu_to_le16(0);
+	cd->wObjectiveFocalLengthMax	= cpu_to_le16(0);
+	cd->wOcularFocalLength		= cpu_to_le16(0);
+	cd->bControlSize		= 3;
+	cd->bmControls[0]		= 2;
+	cd->bmControls[1]		= 0;
+	cd->bmControls[2]		= 0;
+
+	pd = &opts->uvc_processing;
+	pd->bLength			= UVC_DT_PROCESSING_UNIT_SIZE(2);
+	pd->bDescriptorType		= USB_DT_CS_INTERFACE;
+	pd->bDescriptorSubType		= UVC_VC_PROCESSING_UNIT;
+	pd->bUnitID			= 2;
+	pd->bSourceID			= 1;
+	pd->wMaxMultiplier		= cpu_to_le16(16*1024);
+	pd->bControlSize		= 2;
+	pd->bmControls[0]		= 1;
+	pd->bmControls[1]		= 0;
+	pd->iProcessing			= 0;
+
+	od = &opts->uvc_output_terminal;
+	od->bLength			= UVC_DT_OUTPUT_TERMINAL_SIZE;
+	od->bDescriptorType		= USB_DT_CS_INTERFACE;
+	od->bDescriptorSubType		= UVC_VC_OUTPUT_TERMINAL;
+	od->bTerminalID			= 3;
+	od->wTerminalType		= cpu_to_le16(0x0101);
+	od->bAssocTerminal		= 0;
+	od->bSourceID			= 2;
+	od->iTerminal			= 0;
+
+	md = &opts->uvc_color_matching;
+	md->bLength			= UVC_DT_COLOR_MATCHING_SIZE;
+	md->bDescriptorType		= USB_DT_CS_INTERFACE;
+	md->bDescriptorSubType		= UVC_VS_COLORFORMAT;
+	md->bColorPrimaries		= 1;
+	md->bTransferCharacteristics	= 1;
+	md->bMatrixCoefficients		= 4;
+
+	/* Prepare fs control class descriptors for configfs-based gadgets */
+	ctl_cls = opts->uvc_fs_control_cls;
+	ctl_cls[0] = NULL;	/* assigned elsewhere by configfs */
+	ctl_cls[1] = (struct uvc_descriptor_header *)cd;
+	ctl_cls[2] = (struct uvc_descriptor_header *)pd;
+	ctl_cls[3] = (struct uvc_descriptor_header *)od;
+	ctl_cls[4] = NULL;	/* NULL-terminate */
+	opts->fs_control =
+		(const struct uvc_descriptor_header * const *)ctl_cls;
+
+	/* Prepare hs control class descriptors for configfs-based gadgets */
+	ctl_cls = opts->uvc_ss_control_cls;
+	ctl_cls[0] = NULL;	/* assigned elsewhere by configfs */
+	ctl_cls[1] = (struct uvc_descriptor_header *)cd;
+	ctl_cls[2] = (struct uvc_descriptor_header *)pd;
+	ctl_cls[3] = (struct uvc_descriptor_header *)od;
+	ctl_cls[4] = NULL;	/* NULL-terminate */
+	opts->ss_control =
+		(const struct uvc_descriptor_header * const *)ctl_cls;
+
+	opts->streaming_interval = 1;
+	opts->streaming_maxpacket = 1024;
+
+	uvcg_attach_configfs(opts);
+	return &opts->func_inst;
+}
+
+static void uvc_free(struct usb_function *f)
+{
+	struct uvc_device *uvc = to_uvc(f);
+	struct f_uvc_opts *opts = container_of(f->fi, struct f_uvc_opts,
+					       func_inst);
+	--opts->refcnt;
+	kfree(uvc);
+}
+
+static void uvc_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, "%s\n", __func__);
+
+	video_unregister_device(&uvc->vdev);
+	v4l2_device_unregister(&uvc->v4l2_dev);
+	uvc->control_ep->driver_data = NULL;
+	uvc->video.ep->driver_data = NULL;
+
+	usb_ep_free_request(cdev->gadget->ep0, uvc->control_req);
+	kfree(uvc->control_buf);
+
+	usb_free_all_descriptors(f);
+}
+
+static struct usb_function *uvc_alloc(struct usb_function_instance *fi)
+{
+	struct uvc_device *uvc;
+	struct f_uvc_opts *opts;
+	struct uvc_descriptor_header **strm_cls;
+
+	uvc = kzalloc(sizeof(*uvc), GFP_KERNEL);
+	if (uvc == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&uvc->video.mutex);
+	uvc->state = UVC_STATE_DISCONNECTED;
+	opts = fi_to_f_uvc_opts(fi);
+
+	mutex_lock(&opts->lock);
+	if (opts->uvc_fs_streaming_cls) {
+		strm_cls = opts->uvc_fs_streaming_cls;
+		opts->fs_streaming =
+			(const struct uvc_descriptor_header * const *)strm_cls;
+	}
+	if (opts->uvc_hs_streaming_cls) {
+		strm_cls = opts->uvc_hs_streaming_cls;
+		opts->hs_streaming =
+			(const struct uvc_descriptor_header * const *)strm_cls;
+	}
+	if (opts->uvc_ss_streaming_cls) {
+		strm_cls = opts->uvc_ss_streaming_cls;
+		opts->ss_streaming =
+			(const struct uvc_descriptor_header * const *)strm_cls;
+	}
+
+	uvc->desc.fs_control = opts->fs_control;
+	uvc->desc.ss_control = opts->ss_control;
+	uvc->desc.fs_streaming = opts->fs_streaming;
+	uvc->desc.hs_streaming = opts->hs_streaming;
+	uvc->desc.ss_streaming = opts->ss_streaming;
+	++opts->refcnt;
+	mutex_unlock(&opts->lock);
+
+	/* Register the function. */
+	uvc->func.name = "uvc";
+	uvc->func.bind = uvc_function_bind;
+	uvc->func.unbind = uvc_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;
+	uvc->func.free_func = uvc_free;
+
+	return &uvc->func;
+}
+
+DECLARE_USB_FUNCTION_INIT(uvc, uvc_alloc_inst, uvc_alloc);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Laurent Pinchart");