Re: [PATCH v3 1/1] usb: gadget: add raw-gadget interface

Andrey Konovalov
2019-12-18T17:28:36Z

On Wed, Dec 18, 2019 at 2:23 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Wed, Dec 11, 2019 at 07:02:41PM +0100, Andrey Konovalov wrote:
> > 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.
>
> Looks good to me, only minor comments below.

Great, thanks!

About reworking the logging to use dev_err/dbg(): can I pass the
global miscdevice struct into those macros? Or should I pass a pointer
to this struct into all of the functions that print log messages? The
latter seems unnecessarily complex, unless there's a reason to do
that.

For the rest of the comments please see below.

>
> > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> > ---
> > Documentation/usb/index.rst | 1 +
> > Documentation/usb/raw-gadget.rst | 59 ++
> > drivers/usb/gadget/legacy/Kconfig | 8 +
> > drivers/usb/gadget/legacy/Makefile | 1 +
> > drivers/usb/gadget/legacy/raw.c | 1070 +++++++++++++++++++++++++++
> > include/uapi/linux/usb/raw_gadget.h | 167 +++++
> > 6 files changed, 1306 insertions(+)
> > create mode 100644 Documentation/usb/raw-gadget.rst
> > create mode 100644 drivers/usb/gadget/legacy/raw.c
> > create mode 100644 include/uapi/linux/usb/raw_gadget.h
> >
> > diff --git a/Documentation/usb/index.rst b/Documentation/usb/index.rst
> > index e55386a4abfb..90310e2a0c1f 100644
> > --- a/Documentation/usb/index.rst
> > +++ b/Documentation/usb/index.rst
> > @@ -22,6 +22,7 @@ USB support
> > misc_usbsevseg
> > mtouchusb
> > ohci
> > + raw-gadget
> > rio
> > usbip_protocol
> > usbmon
> > diff --git a/Documentation/usb/raw-gadget.rst b/Documentation/usb/raw-gadget.rst
> > new file mode 100644
> > index 000000000000..cbedf5451ed3
> > --- /dev/null
> > +++ b/Documentation/usb/raw-gadget.rst
> > @@ -0,0 +1,59 @@
> > +==============
> > +USB Raw Gadget
> > +==============
> > +
> > +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, use GadgetFS instead.
> > +
> > +Comparison to GadgetFS
> > +~~~~~~~~~~~~~~~~~~~~~~
> > +
> > +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.
> > +
> > +Userspace interface
> > +~~~~~~~~~~~~~~~~~~~
> > +
> > +To create a Raw Gadget instance open /dev/raw-gadget. Multiple raw-gadget
> > +instances (bound to different UDCs) can be used at the same time. The
> > +interaction with the opened file happens through the ioctl() calls, see
> > +comments in include/uapi/linux/usb/raw_gadget.h for details.
> > +
> > +The typical usage of Raw Gadget looks like:
> > +
> > +1. Open Raw Gadget instance via /dev/raw-gadget.
> > +2. Initialize the instance via USB_RAW_IOCTL_INIT.
> > +3. Launch the instance with USB_RAW_IOCTL_RUN.
> > +4. In a loop issue USB_RAW_IOCTL_EVENT_FETCH calls to receive events from
> > + Raw Gadget and react to those depending on what kind of USB device
> > + needs to be emulated.
> > +
> > +Potential future improvements
> > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > +
> > +- Implement ioctl's for setting/clearing halt status on endpoints.
> > +
> > +- Reporting more events (suspend, resume, etc.) through
> > + USB_RAW_IOCTL_EVENT_FETCH.
> > diff --git a/drivers/usb/gadget/legacy/Kconfig b/drivers/usb/gadget/legacy/Kconfig
> > index 119a4e47681f..8c947edf7515 100644
> > --- a/drivers/usb/gadget/legacy/Kconfig
> > +++ b/drivers/usb/gadget/legacy/Kconfig
> > @@ -489,3 +489,11 @@ 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.
>
> No help text saying what the module name would be if selected as one?

Will add in v4.

>
>
> > diff --git a/drivers/usb/gadget/legacy/Makefile b/drivers/usb/gadget/legacy/Makefile
> > index abd0c3e66a05..799feefeee58 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.o
>
> raw.ko? I think we already have a raw.ko in the kernel, shouldn't this
> be usb_raw_gadget.ko or something?
>
> Yeah, we do, look at drivers/char/raw.c. This needs to be changed,
> I can't take it as-is otherwise the builders will croak on it.

OK, I think raw_gadget.ko is short enough and unique. Will change it in in v4.

>
> > diff --git a/drivers/usb/gadget/legacy/raw.c b/drivers/usb/gadget/legacy/raw.c
> > new file mode 100644
> > index 000000000000..fcfa2ebc103e
> > --- /dev/null
> > +++ b/drivers/usb/gadget/legacy/raw.c
> > @@ -0,0 +1,1070 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * USB Raw Gadget driver.
> > + * See Documentation/usb/raw-gadget.rst for more details.
> > + *
> > + * Andrey Konovalov <andreyknvl@gmail.com>
> > + */
> > +
> > +#define pr_fmt(fmt) "raw: %s: " fmt, __func__
>
> "raw gadget"?
>
> This a driver, why do you ever need to do a pr_* call and not a dev_*
> instead?
>
> > +
> > +#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"
>
> You only use this in one place. You can use it in the definition of the
> misc driver name also, right?

Yes, will do in v4.

>
>
> > +
> > +MODULE_DESCRIPTION(DRIVER_DESC);
> > +MODULE_AUTHOR("Andrey Konovalov");
> > +MODULE_LICENSE("GPL");
> > +
> > +/*----------------------------------------------------------------------*/
> > +
> > +#define RAW_EVENT_QUEUE_SIZE 128
> > +
> > +struct raw_event_queue {
> > + spinlock_t lock;
> > + struct semaphore sema;
>
> Two locks for the same structure? That feels "wrong". Why is this?
> document the heck out of it if it is required please.

raw_event_queue_fetch() can be called concurrently, so there 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. Does
this make sense?

I'll add comment explaining that in v4.

>
> > + 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 (queue->size >= RAW_EVENT_QUEUE_SIZE) {
> > + pr_err("too many events\n");
>
> What can someone do with this error?

Hm, I guess we better change this to WARN_ON(), since if this is
triggered, there's probably a flaw in raw gadget that we want to
detect and get fixed.

>
> dev_err() to show exactly where it came from?
>
> > + 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;
> > +
> > + if (down_interruptible(&queue->sema))
> > + return NULL;
> > + spin_lock_irqsave(&queue->lock, flags);
>
> You just locked twice?

See the explanation above.

>
> > + if (WARN_ON(!queue->size))
> > + return NULL;
>
> It's as if you want to trigger syzbot :)
>
> Just log it and return an error.

We do want to trigger syzbot here =) Same as with the upper bound, if
this is hit, there's probably a flaw in raw gadget that we want to
detect and get fixed.

>
> > + 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;
>
> No locking needed?

No. This is called from dev_free(), which is only called when all
references go away, so there are no concurrent accesses.

>
> > +}
> > +
> > +/*----------------------------------------------------------------------*/
> > +
> > +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;
>
> A dev embeds a driver?
>
> Not a pointer?
>
> But you have a kref, so the reference count of this object is there,
> right?

I didn't get this comment, could you elaborate? I can make it a
pointer, but for each raw_dev we have a unique usb_gadget_driver
instance, so embedding it as is is simpler.

>
> > +
> > + /* 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;
>
> No pointer to your misc device? I think you need that for logging.
>
> > +};
> > +
> > +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) {
> > + pr_err("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)
> > + pr_err("failed to queue event\n");
> > +
> > + return ret;
> > +}
> > +
> > +static void gadget_unbind(struct usb_gadget *gadget)
> > +{
> > + struct raw_dev *dev = get_gadget_data(gadget);
> > + unsigned long flags;
> > +
> > + spin_lock_irqsave(&dev->lock, flags);
> > + set_gadget_data(gadget, NULL);
> > + spin_unlock_irqrestore(&dev->lock, flags);
> > + /* Matches kref_get() in gadget_bind(). */
> > + kref_put(&dev->count, dev_free);
>
> What protects the kref from being called 'put' twice on the same
> pointer at the same time? There should be some lock somewhere, right?

Hm, kref_put() does refcount_dec_and_test(), which in turns calls
atomic_dec_and_test(), so this is protected against concurrent puts
(which is the whole idea of kref?), and no locking is needed. Unless I
misunderstand something.

>
>
> > +}
> > +
> > +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) {
> > + pr_err("ignoring, device is not running\n");
> > + ret = -ENODEV;
> > + goto out_unlock;
> > + }
> > + if (dev->ep0_in_pending || dev->ep0_out_pending) {
> > + pr_debug("stalling, already have pending request\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)
> > + pr_err("failed to queue event\n");
> > + goto out;
> > +
> > +out_unlock:
> > + spin_unlock_irqrestore(&dev->lock, flags);
> > +out:
> > + return ret;
> > +}
> > +
> > +/* These are currently ununsed 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 int raw_open(struct inode *inode, struct file *fd)
> > +{
> > + struct raw_dev *dev;
> > +
> > + dev = dev_new();
> > + if (!dev) {
> > + pr_err("failed to created device");
>
> You should have access to your misc device here, so dev_err()?
>
> > + return -ENOMEM;
> > + }
> > + fd->private_data = dev;
> > + dev->state = STATE_DEV_OPENED;
> > + 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);
> > + WARN_ON(ret != 0);
>
> you want to crash? :)

No reason to crash here I guess :) Will remove in v4.

>
> > + /* 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) {
> > + pr_debug("fail, device is not opened\n");
>
> dev_dbg().
>
> > + 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) {
> > + pr_debug("fail, device is not initialized\n");
>
> dev_dbg()
>
> > + 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) {
> > + pr_err("fail, usb_gadget_probe_driver returned %d\n", ret);
>
> dev_err()
>
> same goes for everywhere, no need for any pr_* calls in this driver.
>
> > + 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) {
> > + pr_debug("fail, device is not running\n");
> > + spin_unlock_irqrestore(&dev->lock, flags);
> > + return -EINVAL;
> > + }
> > + if (!dev->gadget) {
> > + pr_debug("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) {
> > + pr_debug("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) {
> > + pr_debug("fail, device is not running\n");
> > + ret = -EINVAL;
> > + goto out_unlock;
> > + }
> > + if (!dev->gadget) {
> > + pr_debug("fail, gadget is not bound\n");
> > + ret = -EBUSY;
> > + goto out_unlock;
> > + }
> > + if (dev->ep0_urb_queued) {
> > + pr_debug("fail, urb already queued\n");
> > + ret = -EBUSY;
> > + goto out_unlock;
> > + }
> > + if ((in && !dev->ep0_in_pending) ||
> > + (!in && !dev->ep0_out_pending)) {
> > + pr_debug("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_ATOMIC);
> > + if (ret) {
> > + pr_err("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) {
> > + pr_debug("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) {
> > + kfree(desc);
> > + return -EINVAL;
> > + }
> > +
> > + spin_lock_irqsave(&dev->lock, flags);
> > + if (dev->state != STATE_DEV_RUNNING) {
> > + pr_debug("fail, device is not running\n");
> > + ret = -EINVAL;
> > + goto out_free;
> > + }
> > + if (!dev->gadget) {
> > + pr_debug("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) {
> > + pr_debug("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) {
> > + pr_err("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) {
> > + pr_err("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;
> > + }
> > +
> > + pr_debug("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) {
> > + pr_debug("fail, device is not running\n");
> > + ret = -EINVAL;
> > + goto out_unlock;
> > + }
> > + if (!dev->gadget) {
> > + pr_debug("fail, gadget is not bound\n");
> > + ret = -EBUSY;
> > + goto out_unlock;
> > + }
> > + if (dev->eps[i].state != STATE_EP_ENABLED) {
> > + pr_debug("fail, endpoint is not enabled\n");
> > + ret = -EINVAL;
> > + goto out_unlock;
> > + }
> > + if (dev->eps[i].disabling) {
> > + pr_debug("fail, disable already in progress\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) {
> > + pr_debug("fail, device is not running\n");
> > + ret = -EINVAL;
> > + goto out_unlock;
> > + }
> > + if (!dev->gadget) {
> > + pr_debug("fail, gadget is not bound\n");
> > + ret = -EBUSY;
> > + goto out_unlock;
> > + }
> > + if (ep->state != STATE_EP_ENABLED) {
> > + pr_debug("fail, endpoint is not enabled\n");
> > + ret = -EBUSY;
> > + goto out_unlock;
> > + }
> > + if (ep->disabling) {
> > + pr_debug("fail, endpoint is being disabled\n");
> > + ret = -EBUSY;
> > + goto out_unlock;
> > + }
> > + if (ep->urb_queued) {
> > + pr_debug("fail, urb already queued\n");
> > + ret = -EBUSY;
> > + goto out_unlock;
> > + }
> > + if ((in && !ep->ep->caps.dir_in) || (!in && ep->ep->caps.dir_in)) {
> > + pr_debug("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_ATOMIC);
> > + if (ret) {
> > + pr_err("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) {
> > + pr_debug("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) {
> > + pr_debug("fail, device is not running\n");
> > + ret = -EINVAL;
> > + goto out_unlock;
> > + }
> > + if (!dev->gadget) {
> > + pr_debug("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) {
> > + pr_debug("fail, device is not running\n");
> > + ret = -EINVAL;
> > + goto out_unlock;
> > + }
> > + if (!dev->gadget) {
> > + pr_debug("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_device = {
> > + .minor = MISC_DYNAMIC_MINOR,
> > + .name = "raw-gadget",
>
> DRIVER_NAME?

Will do in v4.

>
> > + .fops = &raw_fops,
> > +};
> > +
> > +static int __init raw_init(void)
> > +{
> > + int rv;
> > +
> > + rv = misc_register(&raw_device);
> > + if (rv) {
> > + pr_err("failed to register raw-gadget device with %d\n", rv);
> > + return rv;
> > + }
> > + return 0;
> > +}
> > +
> > +static void __exit raw_exit(void)
> > +{
> > + misc_deregister(&raw_device);
> > +}
> > +
> > +module_init(raw_init);
> > +module_exit(raw_exit);
>
> module_misc_device()? :)

Will do in v4.

Thanks!