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 <dbrownell@users.sourceforge.net>
Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/atmel_usba_udc.c

@@ -649,7 +649,13 @@ static int usba_ep_disable(struct usb_ep *_ep)
 
 	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;
@@ -1032,8 +1038,6 @@ static struct usba_udc the_udc = {
 			.release	= nop_release,
 		},
 	},
-
-	.lock	= SPIN_LOCK_UNLOCKED,
 };
 
 /*
@@ -1052,6 +1056,12 @@ static void reset_all_endpoints(struct usba_udc *udc)
 		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);
@@ -1219,7 +1229,7 @@ static inline bool feature_is_ep_halt(struct usb_ctrlrequest *crq)
 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: {
@@ -1693,6 +1703,14 @@ static irqreturn_t usba_udc_irq(int irq, void *devid)
 		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;
@@ -1716,9 +1734,13 @@ static irqreturn_t usba_udc_irq(int irq, void *devid)
 				| 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);
@@ -1751,9 +1773,11 @@ static irqreturn_t usba_vbus_irq(int irq, void *devid)
 			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;
 	}
@@ -1825,7 +1849,7 @@ int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
 
 	if (!udc->pdev)
 		return -ENODEV;
-	if (driver != udc->driver)
+	if (driver != udc->driver || !driver->unbind)
 		return -EINVAL;
 
 	if (udc->vbus_pin != -1)
@@ -1840,6 +1864,9 @@ int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
 	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;
 	udc->driver = NULL;
@@ -1879,6 +1906,7 @@ static int __init usba_udc_probe(struct platform_device *pdev)
 		goto err_get_hclk;
 	}
 
+	spin_lock_init(&udc->lock);
 	udc->pdev = pdev;
 	udc->pclk = pclk;
 	udc->hclk = hclk;