Commit b42e8090 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
Browse files

USB: UDC: Implement udc_async_callbacks in net2280 



This patch adds a udc_async_callbacks handler to the net2280 UDC
driver, which will prevent a theoretical race during gadget unbinding.

The net2280 driver is sufficiently complicated that I didn't want to
mess around with IRQ settings.  Instead, the patch simply adds a new
flag to control async callbacks, and checks the flag before issuing
any of them.

Acked-by: default avatarFelipe Balbi <balbi@kernel.org>
Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20210520202200.GE1216852@rowland.harvard.edu


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 04145a03

drivers/usb/gadget/udc/net2280.c

+32 −17
Original line number Diff line number Diff line
@@ -1617,6 +1617,7 @@ static struct usb_ep *net2280_match_ep(struct usb_gadget *_gadget, 
static int net2280_start(struct usb_gadget *_gadget,

		struct usb_gadget_driver *driver);

static int net2280_stop(struct usb_gadget *_gadget);

static void net2280_async_callbacks(struct usb_gadget *_gadget, bool enable);



static const struct usb_gadget_ops net2280_ops = {

	.get_frame	= net2280_get_frame,
@@ -1625,6 +1626,7 @@ static const struct usb_gadget_ops net2280_ops = { 
	.pullup		= net2280_pullup,

	.udc_start	= net2280_start,

	.udc_stop	= net2280_stop,

	.udc_async_callbacks = net2280_async_callbacks,

	.match_ep	= net2280_match_ep,

};
@@ -2472,7 +2474,7 @@ static void stop_activity(struct net2280 *dev, struct usb_gadget_driver *driver) 
		nuke(&dev->ep[i]);



	/* report disconnect; the driver is already quiesced */

	if (driver) {

	if (dev->async_callbacks && driver) {

		spin_unlock(&dev->lock);

		driver->disconnect(&dev->gadget);

		spin_lock(&dev->lock);
@@ -2502,6 +2504,15 @@ static int net2280_stop(struct usb_gadget *_gadget) 
	return 0;

}



static void net2280_async_callbacks(struct usb_gadget *_gadget, bool enable)

{

	struct net2280	*dev = container_of(_gadget, struct net2280, gadget);



	spin_lock_irq(&dev->lock);

	dev->async_callbacks = enable;

	spin_unlock_irq(&dev->lock);

}



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



/* handle ep0, ep-e, ep-f with 64 byte packets: packet per irq.
@@ -3042,10 +3053,12 @@ static void handle_stat0_irqs_superspeed(struct net2280 *dev, 
				readl(&ep->cfg->ep_cfg));



		ep->responded = 0;

		if (dev->async_callbacks) {

			spin_unlock(&dev->lock);

			tmp = dev->driver->setup(&dev->gadget, &r);

			spin_lock(&dev->lock);

		}

	}

do_stall3:

	if (tmp < 0) {

		ep_vdbg(dev, "req %02x.%02x protocol STALL; stat %d\n",
@@ -3284,10 +3297,12 @@ static void handle_stat0_irqs(struct net2280 *dev, u32 stat) 
				w_value, w_index, w_length,

				readl(&ep->cfg->ep_cfg));

			ep->responded = 0;

			if (dev->async_callbacks) {

				spin_unlock(&dev->lock);

				tmp = dev->driver->setup(&dev->gadget, &u.r);

				spin_lock(&dev->lock);

			}

		}



		/* stall ep0 on error */

		if (tmp < 0) {
@@ -3391,14 +3406,14 @@ __acquires(dev->lock) 
			if (disconnect || reset) {

				stop_activity(dev, dev->driver);

				ep0_start(dev);

				if (dev->async_callbacks) {

					spin_unlock(&dev->lock);

					if (reset)

					usb_gadget_udc_reset

						(&dev->gadget, dev->driver);

						usb_gadget_udc_reset(&dev->gadget, dev->driver);

					else

					(dev->driver->disconnect)

						(&dev->gadget);

						(dev->driver->disconnect)(&dev->gadget);

					spin_lock(&dev->lock);

				}

				return;

			}

		}
@@ -3419,12 +3434,12 @@ __acquires(dev->lock) 
		writel(tmp, &dev->regs->irqstat1);

		spin_unlock(&dev->lock);

		if (stat & BIT(SUSPEND_REQUEST_INTERRUPT)) {

			if (dev->driver->suspend)

			if (dev->async_callbacks && dev->driver->suspend)

				dev->driver->suspend(&dev->gadget);

			if (!enable_suspend)

				stat &= ~BIT(SUSPEND_REQUEST_INTERRUPT);

		} else {

			if (dev->driver->resume)

			if (dev->async_callbacks && dev->driver->resume)

				dev->driver->resume(&dev->gadget);

			/* at high speed, note erratum 0133 */

		}

drivers/usb/gadget/udc/net2280.h

+1 −0
Original line number Diff line number Diff line
@@ -162,6 +162,7 @@ struct net2280 { 
					ltm_enable:1,

					wakeup_enable:1,

					addressed_state:1,

					async_callbacks:1,

					bug7734_patched:1;

	u16				chiprev;

	int enhanced_mode;