USB: atmel_usba_udc fixes, mostly disconnect()

Various fixes to Atmel's high speed UDC driver.

* Issue some missing disconnect() calls. Currently they are only made
when VBUS power goes away (on boards where the driver can sense such
changes), but that's not enough for gadget drivers to clean out all
the state that's needed. Missing calls were:

- After USB reset, before starting enumeration.
- When unregistering a gadget driver, before unbind().

* Don't assume gadget drivers provide disconnect callbacks; make sure
to not call through a null pointer!

* When the driver doesn't provide an unbind() callback, refuse to
unregister it.

Also remove two bogus "error" messages:

* Related to mis-handling of disconnect() ... don't emit error messages
for disconnect() handlers that disable endpoints. All of them should
be doing that; the problem is (unfixed) oddness in atmel_usba_udc.

* Don't emit a diagnostic for a curious and transient nonfatal error
that shows up sometimes with EP0.

Those messages spammed syslog, for no good reason.

Signed-off-by: David Brownell <[e-mail]>
Acked-by: Haavard Skinnemoen <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/gadget/atmel_usba_udc.c

···
 
 	if (!ep->desc) {
 		spin_unlock_irqrestore(&udc->lock, flags);
-		DBG(DBG_ERR, "ep_disable: %s not enabled\n", ep->ep.name);
+		/* REVISIT because this driver disables endpoints in
+		 * reset_all_endpoints() before calling disconnect(),
+		 * most gadget drivers would trigger this non-error ...
+		 */
+		if (udc->gadget.speed != USB_SPEED_UNKNOWN)
+			DBG(DBG_ERR, "ep_disable: %s not enabled\n",
+					ep->ep.name);
 		return -EINVAL;
 	}
 	ep->desc = NULL;
···
 			.release	= nop_release,
 		},
 	},
-
-	.lock	= SPIN_LOCK_UNLOCKED,
 };
 
 /*
···
 		request_complete(ep, req, -ECONNRESET);
 	}
 
+	/* NOTE:  normally, the next call to the gadget driver is in
+	 * charge of disabling endpoints... usually disconnect().
+	 * The exception would be entering a high speed test mode.
+	 *
+	 * FIXME remove this code ... and retest thoroughly.
+	 */
 	list_for_each_entry(ep, &udc->gadget.ep_list, ep.ep_list) {
 		if (ep->desc) {
 			spin_unlock(&udc->lock);
···
 static int handle_ep0_setup(struct usba_udc *udc, struct usba_ep *ep,
 		struct usb_ctrlrequest *crq)
 {
-	int retval = 0;;
+	int retval = 0;
 
 	switch (crq->bRequest) {
 	case USB_REQ_GET_STATUS: {
···
 		usba_writel(udc, INT_CLR, USBA_END_OF_RESET);
 		reset_all_endpoints(udc);
 
+		if (udc->gadget.speed != USB_SPEED_UNKNOWN
+				&& udc->driver->disconnect) {
+			udc->gadget.speed = USB_SPEED_UNKNOWN;
+			spin_unlock(&udc->lock);
+			udc->driver->disconnect(&udc->gadget);
+			spin_lock(&udc->lock);
+		}
+
 		if (status & USBA_HIGH_SPEED) {
 			DBG(DBG_BUS, "High-speed bus reset detected\n");
 			udc->gadget.speed = USB_SPEED_HIGH;
···
 				| USBA_DET_SUSPEND
 				| USBA_END_OF_RESUME));
 
+		/*
+		 * Unclear why we hit this irregularly, e.g. in usbtest,
+		 * but it's clearly harmless...
+		 */
 		if (!(usba_ep_readl(ep0, CFG) & USBA_EPT_MAPPED))
-			dev_warn(&udc->pdev->dev,
-				 "WARNING: EP0 configuration is invalid!\n");
+			dev_dbg(&udc->pdev->dev,
+				 "ODD: EP0 configuration is invalid!\n");
 	}
 
 	spin_unlock(&udc->lock);
···
 			reset_all_endpoints(udc);
 			toggle_bias(0);
 			usba_writel(udc, CTRL, USBA_DISABLE_MASK);
-			spin_unlock(&udc->lock);
-			udc->driver->disconnect(&udc->gadget);
-			spin_lock(&udc->lock);
+			if (udc->driver->disconnect) {
+				spin_unlock(&udc->lock);
+				udc->driver->disconnect(&udc->gadget);
+				spin_lock(&udc->lock);
+			}
 		}
 		udc->vbus_prev = vbus;
 	}
···
 
 	if (!udc->pdev)
 		return -ENODEV;
-	if (driver != udc->driver)
+	if (driver != udc->driver || !driver->unbind)
 		return -EINVAL;
 
 	if (udc->vbus_pin != -1)
···
 	/* This will also disable the DP pullup */
 	toggle_bias(0);
 	usba_writel(udc, CTRL, USBA_DISABLE_MASK);
+
+	if (udc->driver->disconnect)
+		udc->driver->disconnect(&udc->gadget);
 
 	driver->unbind(&udc->gadget);
 	udc->gadget.dev.driver = NULL;
···
 		goto err_get_hclk;
 	}
 
+	spin_lock_init(&udc->lock);
 	udc->pdev = pdev;
 	udc->pclk = pclk;
 	udc->hclk = hclk;