usb: gadget: add raw-gadget interface

USB Raw Gadget is a kernel module that provides a userspace interface for
the USB Gadget subsystem. Essentially it allows to emulate USB devices
from userspace. Enabled with CONFIG_USB_RAW_GADGET. Raw Gadget is
currently a strictly debugging feature and shouldn't be used in
production.

Raw Gadget is similar to GadgetFS, but provides a more low-level and
direct access to the USB Gadget layer for the userspace. The key
differences are:

1. Every USB request is passed to the userspace to get a response, while
   GadgetFS responds to some USB requests internally based on the provided
   descriptors. However note, that the UDC driver might respond to some
   requests on its own and never forward them to the Gadget layer.

2. GadgetFS performs some sanity checks on the provided USB descriptors,
   while Raw Gadget allows you to provide arbitrary data as responses to
   USB requests.

3. Raw Gadget provides a way to select a UDC device/driver to bind to,
   while GadgetFS currently binds to the first available UDC.

4. Raw Gadget uses predictable endpoint names (handles) across different
   UDCs (as long as UDCs have enough endpoints of each required transfer
   type).

5. Raw Gadget has ioctl-based interface instead of a filesystem-based one.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

3 files changed, 1090 insertions, 0 deletions

diff --git a/drivers/usb/gadget/legacy/Kconfig b/drivers/usb/gadget/legacy/Kconfig
index 6e7e1a9202e6..a7064e21d9f2 100644
--- a/drivers/usb/gadget/legacy/Kconfig
+++ b/drivers/usb/gadget/legacy/Kconfig
@@ -516,4 +516,15 @@ config USB_G_WEBCAM
 	  Say "y" to link the driver statically, or "m" to build a
 	  dynamically linked module called "g_webcam".
 
+config USB_RAW_GADGET
+	tristate "USB Raw Gadget"
+	help
+	  USB Raw Gadget is a kernel module that provides a userspace interface
+	  for the USB Gadget subsystem. Essentially it allows to emulate USB
+	  devices from userspace. See Documentation/usb/raw-gadget.rst for
+	  details.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "raw_gadget".
+
 endchoice
diff --git a/drivers/usb/gadget/legacy/Makefile b/drivers/usb/gadget/legacy/Makefile
index abd0c3e66a05..4d864bf82799 100644
--- a/drivers/usb/gadget/legacy/Makefile
+++ b/drivers/usb/gadget/legacy/Makefile
@@ -43,3 +43,4 @@ obj-$(CONFIG_USB_G_WEBCAM)	+= g_webcam.o
 obj-$(CONFIG_USB_G_NCM)		+= g_ncm.o
 obj-$(CONFIG_USB_G_ACM_MS)	+= g_acm_ms.o
 obj-$(CONFIG_USB_GADGET_TARGET)	+= tcm_usb_gadget.o
+obj-$(CONFIG_USB_RAW_GADGET)	+= raw_gadget.o
diff --git a/drivers/usb/gadget/legacy/raw_gadget.c b/drivers/usb/gadget/legacy/raw_gadget.c
new file mode 100644
index 000000000000..76406343fbe5
--- /dev/null
+++ b/drivers/usb/gadget/legacy/raw_gadget.c
@@ -0,0 +1,1078 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * USB Raw Gadget driver.
+ * See Documentation/usb/raw-gadget.rst for more details.
+ *
+ * Andrey Konovalov <andreyknvl@gmail.com>
+ */
+
+#include <linux/compiler.h>
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/kref.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/semaphore.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/wait.h>
+
+#include <linux/usb.h>
+#include <linux/usb/ch9.h>
+#include <linux/usb/ch11.h>
+#include <linux/usb/gadget.h>
+
+#include <uapi/linux/usb/raw_gadget.h>
+
+#define	DRIVER_DESC "USB Raw Gadget"
+#define DRIVER_NAME "raw-gadget"
+
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_AUTHOR("Andrey Konovalov");
+MODULE_LICENSE("GPL");
+
+/*----------------------------------------------------------------------*/
+
+#define RAW_EVENT_QUEUE_SIZE	16
+
+struct raw_event_queue {
+	/* See the comment in raw_event_queue_fetch() for locking details. */
+	spinlock_t		lock;
+	struct semaphore	sema;
+	struct usb_raw_event	*events[RAW_EVENT_QUEUE_SIZE];
+	int			size;
+};
+
+static void raw_event_queue_init(struct raw_event_queue *queue)
+{
+	spin_lock_init(&queue->lock);
+	sema_init(&queue->sema, 0);
+	queue->size = 0;
+}
+
+static int raw_event_queue_add(struct raw_event_queue *queue,
+	enum usb_raw_event_type type, size_t length, const void *data)
+{
+	unsigned long flags;
+	struct usb_raw_event *event;
+
+	spin_lock_irqsave(&queue->lock, flags);
+	if (WARN_ON(queue->size >= RAW_EVENT_QUEUE_SIZE)) {
+		spin_unlock_irqrestore(&queue->lock, flags);
+		return -ENOMEM;
+	}
+	event = kmalloc(sizeof(*event) + length, GFP_ATOMIC);
+	if (!event) {
+		spin_unlock_irqrestore(&queue->lock, flags);
+		return -ENOMEM;
+	}
+	event->type = type;
+	event->length = length;
+	if (event->length)
+		memcpy(&event->data[0], data, length);
+	queue->events[queue->size] = event;
+	queue->size++;
+	up(&queue->sema);
+	spin_unlock_irqrestore(&queue->lock, flags);
+	return 0;
+}
+
+static struct usb_raw_event *raw_event_queue_fetch(
+				struct raw_event_queue *queue)
+{
+	unsigned long flags;
+	struct usb_raw_event *event;
+
+	/*
+	 * This function can be called concurrently. We first check that
+	 * there's at least one event queued by decrementing the semaphore,
+	 * and then take the lock to protect queue struct fields.
+	 */
+	if (down_interruptible(&queue->sema))
+		return NULL;
+	spin_lock_irqsave(&queue->lock, flags);
+	if (WARN_ON(!queue->size))
+		return NULL;
+	event = queue->events[0];
+	queue->size--;
+	memmove(&queue->events[0], &queue->events[1],
+			queue->size * sizeof(queue->events[0]));
+	spin_unlock_irqrestore(&queue->lock, flags);
+	return event;
+}
+
+static void raw_event_queue_destroy(struct raw_event_queue *queue)
+{
+	int i;
+
+	for (i = 0; i < queue->size; i++)
+		kfree(queue->events[i]);
+	queue->size = 0;
+}
+
+/*----------------------------------------------------------------------*/
+
+struct raw_dev;
+
+#define USB_RAW_MAX_ENDPOINTS 32
+
+enum ep_state {
+	STATE_EP_DISABLED,
+	STATE_EP_ENABLED,
+};
+
+struct raw_ep {
+	struct raw_dev		*dev;
+	enum ep_state		state;
+	struct usb_ep		*ep;
+	struct usb_request	*req;
+	bool			urb_queued;
+	bool			disabling;
+	ssize_t			status;
+};
+
+enum dev_state {
+	STATE_DEV_INVALID = 0,
+	STATE_DEV_OPENED,
+	STATE_DEV_INITIALIZED,
+	STATE_DEV_RUNNING,
+	STATE_DEV_CLOSED,
+	STATE_DEV_FAILED
+};
+
+struct raw_dev {
+	struct kref			count;
+	spinlock_t			lock;
+
+	const char			*udc_name;
+	struct usb_gadget_driver	driver;
+
+	/* Reference to misc device: */
+	struct device			*dev;
+
+	/* Protected by lock: */
+	enum dev_state			state;
+	bool				gadget_registered;
+	struct usb_gadget		*gadget;
+	struct usb_request		*req;
+	bool				ep0_in_pending;
+	bool				ep0_out_pending;
+	bool				ep0_urb_queued;
+	ssize_t				ep0_status;
+	struct raw_ep			eps[USB_RAW_MAX_ENDPOINTS];
+
+	struct completion		ep0_done;
+	struct raw_event_queue		queue;
+};
+
+static struct raw_dev *dev_new(void)
+{
+	struct raw_dev *dev;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return NULL;
+	/* Matches kref_put() in raw_release(). */
+	kref_init(&dev->count);
+	spin_lock_init(&dev->lock);
+	init_completion(&dev->ep0_done);
+	raw_event_queue_init(&dev->queue);
+	return dev;
+}
+
+static void dev_free(struct kref *kref)
+{
+	struct raw_dev *dev = container_of(kref, struct raw_dev, count);
+	int i;
+
+	kfree(dev->udc_name);
+	kfree(dev->driver.udc_name);
+	if (dev->req) {
+		if (dev->ep0_urb_queued)
+			usb_ep_dequeue(dev->gadget->ep0, dev->req);
+		usb_ep_free_request(dev->gadget->ep0, dev->req);
+	}
+	raw_event_queue_destroy(&dev->queue);
+	for (i = 0; i < USB_RAW_MAX_ENDPOINTS; i++) {
+		if (dev->eps[i].state != STATE_EP_ENABLED)
+			continue;
+		usb_ep_disable(dev->eps[i].ep);
+		usb_ep_free_request(dev->eps[i].ep, dev->eps[i].req);
+		kfree(dev->eps[i].ep->desc);
+		dev->eps[i].state = STATE_EP_DISABLED;
+	}
+	kfree(dev);
+}
+
+/*----------------------------------------------------------------------*/
+
+static int raw_queue_event(struct raw_dev *dev,
+	enum usb_raw_event_type type, size_t length, const void *data)
+{
+	int ret = 0;
+	unsigned long flags;
+
+	ret = raw_event_queue_add(&dev->queue, type, length, data);
+	if (ret < 0) {
+		spin_lock_irqsave(&dev->lock, flags);
+		dev->state = STATE_DEV_FAILED;
+		spin_unlock_irqrestore(&dev->lock, flags);
+	}
+	return ret;
+}
+
+static void gadget_ep0_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	struct raw_dev *dev = req->context;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	if (req->status)
+		dev->ep0_status = req->status;
+	else
+		dev->ep0_status = req->actual;
+	if (dev->ep0_in_pending)
+		dev->ep0_in_pending = false;
+	else
+		dev->ep0_out_pending = false;
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	complete(&dev->ep0_done);
+}
+
+static int gadget_bind(struct usb_gadget *gadget,
+			struct usb_gadget_driver *driver)
+{
+	int ret = 0;
+	struct raw_dev *dev = container_of(driver, struct raw_dev, driver);
+	struct usb_request *req;
+	unsigned long flags;
+
+	if (strcmp(gadget->name, dev->udc_name) != 0)
+		return -ENODEV;
+
+	set_gadget_data(gadget, dev);
+	req = usb_ep_alloc_request(gadget->ep0, GFP_KERNEL);
+	if (!req) {
+		dev_err(&gadget->dev, "usb_ep_alloc_request failed\n");
+		set_gadget_data(gadget, NULL);
+		return -ENOMEM;
+	}
+
+	spin_lock_irqsave(&dev->lock, flags);
+	dev->req = req;
+	dev->req->context = dev;
+	dev->req->complete = gadget_ep0_complete;
+	dev->gadget = gadget;
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	/* Matches kref_put() in gadget_unbind(). */
+	kref_get(&dev->count);
+
+	ret = raw_queue_event(dev, USB_RAW_EVENT_CONNECT, 0, NULL);
+	if (ret < 0)
+		dev_err(&gadget->dev, "failed to queue event\n");
+
+	return ret;
+}
+
+static void gadget_unbind(struct usb_gadget *gadget)
+{
+	struct raw_dev *dev = get_gadget_data(gadget);
+
+	set_gadget_data(gadget, NULL);
+	/* Matches kref_get() in gadget_bind(). */
+	kref_put(&dev->count, dev_free);
+}
+
+static int gadget_setup(struct usb_gadget *gadget,
+			const struct usb_ctrlrequest *ctrl)
+{
+	int ret = 0;
+	struct raw_dev *dev = get_gadget_data(gadget);
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	if (dev->state != STATE_DEV_RUNNING) {
+		dev_err(&gadget->dev, "ignoring, device is not running\n");
+		ret = -ENODEV;
+		goto out_unlock;
+	}
+	if (dev->ep0_in_pending || dev->ep0_out_pending) {
+		dev_dbg(&gadget->dev, "stalling, request already pending\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	if ((ctrl->bRequestType & USB_DIR_IN) && ctrl->wLength)
+		dev->ep0_in_pending = true;
+	else
+		dev->ep0_out_pending = true;
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	ret = raw_queue_event(dev, USB_RAW_EVENT_CONTROL, sizeof(*ctrl), ctrl);
+	if (ret < 0)
+		dev_err(&gadget->dev, "failed to queue event\n");
+	goto out;
+
+out_unlock:
+	spin_unlock_irqrestore(&dev->lock, flags);
+out:
+	return ret;
+}
+
+/* These are currently unused but present in case UDC driver requires them. */
+static void gadget_disconnect(struct usb_gadget *gadget) { }
+static void gadget_suspend(struct usb_gadget *gadget) { }
+static void gadget_resume(struct usb_gadget *gadget) { }
+static void gadget_reset(struct usb_gadget *gadget) { }
+
+/*----------------------------------------------------------------------*/
+
+static struct miscdevice raw_misc_device;
+
+static int raw_open(struct inode *inode, struct file *fd)
+{
+	struct raw_dev *dev;
+
+	/* Nonblocking I/O is not supported yet. */
+	if (fd->f_flags & O_NONBLOCK)
+		return -EINVAL;
+
+	dev = dev_new();
+	if (!dev)
+		return -ENOMEM;
+	fd->private_data = dev;
+	dev->state = STATE_DEV_OPENED;
+	dev->dev = raw_misc_device.this_device;
+	return 0;
+}
+
+static int raw_release(struct inode *inode, struct file *fd)
+{
+	int ret = 0;
+	struct raw_dev *dev = fd->private_data;
+	unsigned long flags;
+	bool unregister = false;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	dev->state = STATE_DEV_CLOSED;
+	if (!dev->gadget) {
+		spin_unlock_irqrestore(&dev->lock, flags);
+		goto out_put;
+	}
+	if (dev->gadget_registered)
+		unregister = true;
+	dev->gadget_registered = false;
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	if (unregister) {
+		ret = usb_gadget_unregister_driver(&dev->driver);
+		if (ret != 0)
+			dev_err(dev->dev,
+				"usb_gadget_unregister_driver() failed with %d\n",
+				ret);
+		/* Matches kref_get() in raw_ioctl_run(). */
+		kref_put(&dev->count, dev_free);
+	}
+
+out_put:
+	/* Matches dev_new() in raw_open(). */
+	kref_put(&dev->count, dev_free);
+	return ret;
+}
+
+/*----------------------------------------------------------------------*/
+
+static int raw_ioctl_init(struct raw_dev *dev, unsigned long value)
+{
+	int ret = 0;
+	struct usb_raw_init arg;
+	char *udc_driver_name;
+	char *udc_device_name;
+	unsigned long flags;
+
+	ret = copy_from_user(&arg, (void __user *)value, sizeof(arg));
+	if (ret)
+		return ret;
+
+	switch (arg.speed) {
+	case USB_SPEED_UNKNOWN:
+		arg.speed = USB_SPEED_HIGH;
+		break;
+	case USB_SPEED_LOW:
+	case USB_SPEED_FULL:
+	case USB_SPEED_HIGH:
+	case USB_SPEED_SUPER:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	udc_driver_name = kmalloc(UDC_NAME_LENGTH_MAX, GFP_KERNEL);
+	if (!udc_driver_name)
+		return -ENOMEM;
+	ret = strscpy(udc_driver_name, &arg.driver_name[0],
+				UDC_NAME_LENGTH_MAX);
+	if (ret < 0) {
+		kfree(udc_driver_name);
+		return ret;
+	}
+	ret = 0;
+
+	udc_device_name = kmalloc(UDC_NAME_LENGTH_MAX, GFP_KERNEL);
+	if (!udc_device_name) {
+		kfree(udc_driver_name);
+		return -ENOMEM;
+	}
+	ret = strscpy(udc_device_name, &arg.device_name[0],
+				UDC_NAME_LENGTH_MAX);
+	if (ret < 0) {
+		kfree(udc_driver_name);
+		kfree(udc_device_name);
+		return ret;
+	}
+	ret = 0;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	if (dev->state != STATE_DEV_OPENED) {
+		dev_dbg(dev->dev, "fail, device is not opened\n");
+		kfree(udc_driver_name);
+		kfree(udc_device_name);
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	dev->udc_name = udc_driver_name;
+
+	dev->driver.function = DRIVER_DESC;
+	dev->driver.max_speed = arg.speed;
+	dev->driver.setup = gadget_setup;
+	dev->driver.disconnect = gadget_disconnect;
+	dev->driver.bind = gadget_bind;
+	dev->driver.unbind = gadget_unbind;
+	dev->driver.suspend = gadget_suspend;
+	dev->driver.resume = gadget_resume;
+	dev->driver.reset = gadget_reset;
+	dev->driver.driver.name = DRIVER_NAME;
+	dev->driver.udc_name = udc_device_name;
+	dev->driver.match_existing_only = 1;
+
+	dev->state = STATE_DEV_INITIALIZED;
+
+out_unlock:
+	spin_unlock_irqrestore(&dev->lock, flags);
+	return ret;
+}
+
+static int raw_ioctl_run(struct raw_dev *dev, unsigned long value)
+{
+	int ret = 0;
+	unsigned long flags;
+
+	if (value)
+		return -EINVAL;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	if (dev->state != STATE_DEV_INITIALIZED) {
+		dev_dbg(dev->dev, "fail, device is not initialized\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	ret = usb_gadget_probe_driver(&dev->driver);
+
+	spin_lock_irqsave(&dev->lock, flags);
+	if (ret) {
+		dev_err(dev->dev,
+			"fail, usb_gadget_probe_driver returned %d\n", ret);
+		dev->state = STATE_DEV_FAILED;
+		goto out_unlock;
+	}
+	dev->gadget_registered = true;
+	dev->state = STATE_DEV_RUNNING;
+	/* Matches kref_put() in raw_release(). */
+	kref_get(&dev->count);
+
+out_unlock:
+	spin_unlock_irqrestore(&dev->lock, flags);
+	return ret;
+}
+
+static int raw_ioctl_event_fetch(struct raw_dev *dev, unsigned long value)
+{
+	int ret = 0;
+	struct usb_raw_event arg;
+	unsigned long flags;
+	struct usb_raw_event *event;
+	uint32_t length;
+
+	ret = copy_from_user(&arg, (void __user *)value, sizeof(arg));
+	if (ret)
+		return ret;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	if (dev->state != STATE_DEV_RUNNING) {
+		dev_dbg(dev->dev, "fail, device is not running\n");
+		spin_unlock_irqrestore(&dev->lock, flags);
+		return -EINVAL;
+	}
+	if (!dev->gadget) {
+		dev_dbg(dev->dev, "fail, gadget is not bound\n");
+		spin_unlock_irqrestore(&dev->lock, flags);
+		return -EBUSY;
+	}
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	event = raw_event_queue_fetch(&dev->queue);
+	if (!event) {
+		dev_dbg(&dev->gadget->dev, "event fetching interrupted\n");
+		return -EINTR;
+	}
+	length = min(arg.length, event->length);
+	ret = copy_to_user((void __user *)value, event,
+				sizeof(*event) + length);
+	return ret;
+}
+
+static void *raw_alloc_io_data(struct usb_raw_ep_io *io, void __user *ptr,
+				bool get_from_user)
+{
+	int ret;
+	void *data;
+
+	ret = copy_from_user(io, ptr, sizeof(*io));
+	if (ret)
+		return ERR_PTR(ret);
+	if (io->ep >= USB_RAW_MAX_ENDPOINTS)
+		return ERR_PTR(-EINVAL);
+	if (!usb_raw_io_flags_valid(io->flags))
+		return ERR_PTR(-EINVAL);
+	if (io->length > PAGE_SIZE)
+		return ERR_PTR(-EINVAL);
+	if (get_from_user)
+		data = memdup_user(ptr + sizeof(*io), io->length);
+	else {
+		data = kmalloc(io->length, GFP_KERNEL);
+		if (!data)
+			data = ERR_PTR(-ENOMEM);
+	}
+	return data;
+}
+
+static int raw_process_ep0_io(struct raw_dev *dev, struct usb_raw_ep_io *io,
+				void *data, bool in)
+{
+	int ret = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	if (dev->state != STATE_DEV_RUNNING) {
+		dev_dbg(dev->dev, "fail, device is not running\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	if (!dev->gadget) {
+		dev_dbg(dev->dev, "fail, gadget is not bound\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	if (dev->ep0_urb_queued) {
+		dev_dbg(&dev->gadget->dev, "fail, urb already queued\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	if ((in && !dev->ep0_in_pending) ||
+			(!in && !dev->ep0_out_pending)) {
+		dev_dbg(&dev->gadget->dev, "fail, wrong direction\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	if (WARN_ON(in && dev->ep0_out_pending)) {
+		ret = -ENODEV;
+		dev->state = STATE_DEV_FAILED;
+		goto out_done;
+	}
+	if (WARN_ON(!in && dev->ep0_in_pending)) {
+		ret = -ENODEV;
+		dev->state = STATE_DEV_FAILED;
+		goto out_done;
+	}
+
+	dev->req->buf = data;
+	dev->req->length = io->length;
+	dev->req->zero = usb_raw_io_flags_zero(io->flags);
+	dev->ep0_urb_queued = true;
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	ret = usb_ep_queue(dev->gadget->ep0, dev->req, GFP_KERNEL);
+	if (ret) {
+		dev_err(&dev->gadget->dev,
+				"fail, usb_ep_queue returned %d\n", ret);
+		spin_lock_irqsave(&dev->lock, flags);
+		dev->state = STATE_DEV_FAILED;
+		goto out_done;
+	}
+
+	ret = wait_for_completion_interruptible(&dev->ep0_done);
+	if (ret) {
+		dev_dbg(&dev->gadget->dev, "wait interrupted\n");
+		usb_ep_dequeue(dev->gadget->ep0, dev->req);
+		wait_for_completion(&dev->ep0_done);
+		spin_lock_irqsave(&dev->lock, flags);
+		goto out_done;
+	}
+
+	spin_lock_irqsave(&dev->lock, flags);
+	ret = dev->ep0_status;
+
+out_done:
+	dev->ep0_urb_queued = false;
+out_unlock:
+	spin_unlock_irqrestore(&dev->lock, flags);
+	return ret;
+}
+
+static int raw_ioctl_ep0_write(struct raw_dev *dev, unsigned long value)
+{
+	int ret = 0;
+	void *data;
+	struct usb_raw_ep_io io;
+
+	data = raw_alloc_io_data(&io, (void __user *)value, true);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+	ret = raw_process_ep0_io(dev, &io, data, true);
+	kfree(data);
+	return ret;
+}
+
+static int raw_ioctl_ep0_read(struct raw_dev *dev, unsigned long value)
+{
+	int ret = 0;
+	void *data;
+	struct usb_raw_ep_io io;
+	unsigned int length;
+
+	data = raw_alloc_io_data(&io, (void __user *)value, false);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+	ret = raw_process_ep0_io(dev, &io, data, false);
+	if (ret < 0) {
+		kfree(data);
+		return ret;
+	}
+	length = min(io.length, (unsigned int)ret);
+	ret = copy_to_user((void __user *)(value + sizeof(io)), data, length);
+	kfree(data);
+	return ret;
+}
+
+static bool check_ep_caps(struct usb_ep *ep,
+				struct usb_endpoint_descriptor *desc)
+{
+	switch (usb_endpoint_type(desc)) {
+	case USB_ENDPOINT_XFER_ISOC:
+		if (!ep->caps.type_iso)
+			return false;
+		break;
+	case USB_ENDPOINT_XFER_BULK:
+		if (!ep->caps.type_bulk)
+			return false;
+		break;
+	case USB_ENDPOINT_XFER_INT:
+		if (!ep->caps.type_int)
+			return false;
+		break;
+	default:
+		return false;
+	}
+
+	if (usb_endpoint_dir_in(desc) && !ep->caps.dir_in)
+		return false;
+	if (usb_endpoint_dir_out(desc) && !ep->caps.dir_out)
+		return false;
+
+	return true;
+}
+
+static int raw_ioctl_ep_enable(struct raw_dev *dev, unsigned long value)
+{
+	int ret = 0, i;
+	unsigned long flags;
+	struct usb_endpoint_descriptor *desc;
+	struct usb_ep *ep = NULL;
+
+	desc = memdup_user((void __user *)value, sizeof(*desc));
+	if (IS_ERR(desc))
+		return PTR_ERR(desc);
+
+	/*
+	 * Endpoints with a maxpacket length of 0 can cause crashes in UDC
+	 * drivers.
+	 */
+	if (usb_endpoint_maxp(desc) == 0) {
+		dev_dbg(dev->dev, "fail, bad endpoint maxpacket\n");
+		kfree(desc);
+		return -EINVAL;
+	}
+
+	spin_lock_irqsave(&dev->lock, flags);
+	if (dev->state != STATE_DEV_RUNNING) {
+		dev_dbg(dev->dev, "fail, device is not running\n");
+		ret = -EINVAL;
+		goto out_free;
+	}
+	if (!dev->gadget) {
+		dev_dbg(dev->dev, "fail, gadget is not bound\n");
+		ret = -EBUSY;
+		goto out_free;
+	}
+
+	for (i = 0; i < USB_RAW_MAX_ENDPOINTS; i++) {
+		if (dev->eps[i].state == STATE_EP_ENABLED)
+			continue;
+		break;
+	}
+	if (i == USB_RAW_MAX_ENDPOINTS) {
+		dev_dbg(&dev->gadget->dev,
+				"fail, no device endpoints available\n");
+		ret = -EBUSY;
+		goto out_free;
+	}
+
+	gadget_for_each_ep(ep, dev->gadget) {
+		if (ep->enabled)
+			continue;
+		if (!check_ep_caps(ep, desc))
+			continue;
+		ep->desc = desc;
+		ret = usb_ep_enable(ep);
+		if (ret < 0) {
+			dev_err(&dev->gadget->dev,
+				"fail, usb_ep_enable returned %d\n", ret);
+			goto out_free;
+		}
+		dev->eps[i].req = usb_ep_alloc_request(ep, GFP_ATOMIC);
+		if (!dev->eps[i].req) {
+			dev_err(&dev->gadget->dev,
+				"fail, usb_ep_alloc_request failed\n");
+			usb_ep_disable(ep);
+			ret = -ENOMEM;
+			goto out_free;
+		}
+		dev->eps[i].ep = ep;
+		dev->eps[i].state = STATE_EP_ENABLED;
+		ep->driver_data = &dev->eps[i];
+		ret = i;
+		goto out_unlock;
+	}
+
+	dev_dbg(&dev->gadget->dev, "fail, no gadget endpoints available\n");
+	ret = -EBUSY;
+
+out_free:
+	kfree(desc);
+out_unlock:
+	spin_unlock_irqrestore(&dev->lock, flags);
+	return ret;
+}
+
+static int raw_ioctl_ep_disable(struct raw_dev *dev, unsigned long value)
+{
+	int ret = 0, i = value;
+	unsigned long flags;
+	const void *desc;
+
+	if (i < 0 || i >= USB_RAW_MAX_ENDPOINTS)
+		return -EINVAL;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	if (dev->state != STATE_DEV_RUNNING) {
+		dev_dbg(dev->dev, "fail, device is not running\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	if (!dev->gadget) {
+		dev_dbg(dev->dev, "fail, gadget is not bound\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	if (dev->eps[i].state != STATE_EP_ENABLED) {
+		dev_dbg(&dev->gadget->dev, "fail, endpoint is not enabled\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	if (dev->eps[i].disabling) {
+		dev_dbg(&dev->gadget->dev,
+				"fail, disable already in progress\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	if (dev->eps[i].urb_queued) {
+		dev_dbg(&dev->gadget->dev,
+				"fail, waiting for urb completion\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	dev->eps[i].disabling = true;
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	usb_ep_disable(dev->eps[i].ep);
+
+	spin_lock_irqsave(&dev->lock, flags);
+	usb_ep_free_request(dev->eps[i].ep, dev->eps[i].req);
+	desc = dev->eps[i].ep->desc;
+	dev->eps[i].ep = NULL;
+	dev->eps[i].state = STATE_EP_DISABLED;
+	kfree(desc);
+	dev->eps[i].disabling = false;
+
+out_unlock:
+	spin_unlock_irqrestore(&dev->lock, flags);
+	return ret;
+}
+
+static void gadget_ep_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	struct raw_ep *r_ep = (struct raw_ep *)ep->driver_data;
+	struct raw_dev *dev = r_ep->dev;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	if (req->status)
+		r_ep->status = req->status;
+	else
+		r_ep->status = req->actual;
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	complete((struct completion *)req->context);
+}
+
+static int raw_process_ep_io(struct raw_dev *dev, struct usb_raw_ep_io *io,
+				void *data, bool in)
+{
+	int ret = 0;
+	unsigned long flags;
+	struct raw_ep *ep = &dev->eps[io->ep];
+	DECLARE_COMPLETION_ONSTACK(done);
+
+	spin_lock_irqsave(&dev->lock, flags);
+	if (dev->state != STATE_DEV_RUNNING) {
+		dev_dbg(dev->dev, "fail, device is not running\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	if (!dev->gadget) {
+		dev_dbg(dev->dev, "fail, gadget is not bound\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	if (ep->state != STATE_EP_ENABLED) {
+		dev_dbg(&dev->gadget->dev, "fail, endpoint is not enabled\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	if (ep->disabling) {
+		dev_dbg(&dev->gadget->dev,
+				"fail, endpoint is already being disabled\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	if (ep->urb_queued) {
+		dev_dbg(&dev->gadget->dev, "fail, urb already queued\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	if ((in && !ep->ep->caps.dir_in) || (!in && ep->ep->caps.dir_in)) {
+		dev_dbg(&dev->gadget->dev, "fail, wrong direction\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	ep->dev = dev;
+	ep->req->context = &done;
+	ep->req->complete = gadget_ep_complete;
+	ep->req->buf = data;
+	ep->req->length = io->length;
+	ep->req->zero = usb_raw_io_flags_zero(io->flags);
+	ep->urb_queued = true;
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	ret = usb_ep_queue(ep->ep, ep->req, GFP_KERNEL);
+	if (ret) {
+		dev_err(&dev->gadget->dev,
+				"fail, usb_ep_queue returned %d\n", ret);
+		spin_lock_irqsave(&dev->lock, flags);
+		dev->state = STATE_DEV_FAILED;
+		goto out_done;
+	}
+
+	ret = wait_for_completion_interruptible(&done);
+	if (ret) {
+		dev_dbg(&dev->gadget->dev, "wait interrupted\n");
+		usb_ep_dequeue(ep->ep, ep->req);
+		wait_for_completion(&done);
+		spin_lock_irqsave(&dev->lock, flags);
+		goto out_done;
+	}
+
+	spin_lock_irqsave(&dev->lock, flags);
+	ret = ep->status;
+
+out_done:
+	ep->urb_queued = false;
+out_unlock:
+	spin_unlock_irqrestore(&dev->lock, flags);
+	return ret;
+}
+
+static int raw_ioctl_ep_write(struct raw_dev *dev, unsigned long value)
+{
+	int ret = 0;
+	char *data;
+	struct usb_raw_ep_io io;
+
+	data = raw_alloc_io_data(&io, (void __user *)value, true);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+	ret = raw_process_ep_io(dev, &io, data, true);
+	kfree(data);
+	return ret;
+}
+
+static int raw_ioctl_ep_read(struct raw_dev *dev, unsigned long value)
+{
+	int ret = 0;
+	char *data;
+	struct usb_raw_ep_io io;
+	unsigned int length;
+
+	data = raw_alloc_io_data(&io, (void __user *)value, false);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+	ret = raw_process_ep_io(dev, &io, data, false);
+	if (ret < 0) {
+		kfree(data);
+		return ret;
+	}
+	length = min(io.length, (unsigned int)ret);
+	ret = copy_to_user((void __user *)(value + sizeof(io)), data, length);
+	kfree(data);
+	return ret;
+}
+
+static int raw_ioctl_configure(struct raw_dev *dev, unsigned long value)
+{
+	int ret = 0;
+	unsigned long flags;
+
+	if (value)
+		return -EINVAL;
+	spin_lock_irqsave(&dev->lock, flags);
+	if (dev->state != STATE_DEV_RUNNING) {
+		dev_dbg(dev->dev, "fail, device is not running\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	if (!dev->gadget) {
+		dev_dbg(dev->dev, "fail, gadget is not bound\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	usb_gadget_set_state(dev->gadget, USB_STATE_CONFIGURED);
+
+out_unlock:
+	spin_unlock_irqrestore(&dev->lock, flags);
+	return ret;
+}
+
+static int raw_ioctl_vbus_draw(struct raw_dev *dev, unsigned long value)
+{
+	int ret = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	if (dev->state != STATE_DEV_RUNNING) {
+		dev_dbg(dev->dev, "fail, device is not running\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	if (!dev->gadget) {
+		dev_dbg(dev->dev, "fail, gadget is not bound\n");
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	usb_gadget_vbus_draw(dev->gadget, 2 * value);
+
+out_unlock:
+	spin_unlock_irqrestore(&dev->lock, flags);
+	return ret;
+}
+
+static long raw_ioctl(struct file *fd, unsigned int cmd, unsigned long value)
+{
+	struct raw_dev *dev = fd->private_data;
+	int ret = 0;
+
+	if (!dev)
+		return -EBUSY;
+
+	switch (cmd) {
+	case USB_RAW_IOCTL_INIT:
+		ret = raw_ioctl_init(dev, value);
+		break;
+	case USB_RAW_IOCTL_RUN:
+		ret = raw_ioctl_run(dev, value);
+		break;
+	case USB_RAW_IOCTL_EVENT_FETCH:
+		ret = raw_ioctl_event_fetch(dev, value);
+		break;
+	case USB_RAW_IOCTL_EP0_WRITE:
+		ret = raw_ioctl_ep0_write(dev, value);
+		break;
+	case USB_RAW_IOCTL_EP0_READ:
+		ret = raw_ioctl_ep0_read(dev, value);
+		break;
+	case USB_RAW_IOCTL_EP_ENABLE:
+		ret = raw_ioctl_ep_enable(dev, value);
+		break;
+	case USB_RAW_IOCTL_EP_DISABLE:
+		ret = raw_ioctl_ep_disable(dev, value);
+		break;
+	case USB_RAW_IOCTL_EP_WRITE:
+		ret = raw_ioctl_ep_write(dev, value);
+		break;
+	case USB_RAW_IOCTL_EP_READ:
+		ret = raw_ioctl_ep_read(dev, value);
+		break;
+	case USB_RAW_IOCTL_CONFIGURE:
+		ret = raw_ioctl_configure(dev, value);
+		break;
+	case USB_RAW_IOCTL_VBUS_DRAW:
+		ret = raw_ioctl_vbus_draw(dev, value);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+/*----------------------------------------------------------------------*/
+
+static const struct file_operations raw_fops = {
+	.open =			raw_open,
+	.unlocked_ioctl =	raw_ioctl,
+	.compat_ioctl =		raw_ioctl,
+	.release =		raw_release,
+	.llseek =		no_llseek,
+};
+
+static struct miscdevice raw_misc_device = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = DRIVER_NAME,
+	.fops = &raw_fops,
+};
+
+module_misc_device(raw_misc_device);