usb: gadgetfs remove delayed init mode

Gadgetfs had a mode in which endpoint descriptors were written by the user
program before connection.  This mode had some bugs, and hasn't seen much
(if any) use.  This patch removes that mode, leaving the mode of operation
where the user program waits for endpoint 0 to report a SET_CONFIGURATION,
and only then configures the endpoints.

From: "Phil Endecott" <spam_from_usb_devel@chezphil.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/inode.c

@@ -59,11 +59,11 @@
  *   may serve as a source of device events, used to handle all control
  *   requests other than basic enumeration.
  *
- * - Then either immediately, or after a SET_CONFIGURATION control request,
- *   ep_config() is called when each /dev/gadget/ep* file is configured
- *   (by writing endpoint descriptors).  Afterwards these files are used
- *   to write() IN data or to read() OUT data.  To halt the endpoint, a
- *   "wrong direction" request is issued (like reading an IN endpoint).
+ * - Then, after a SET_CONFIGURATION control request, ep_config() is
+ *   called when each /dev/gadget/ep* file is configured (by writing
+ *   endpoint descriptors).  Afterwards these files are used to write()
+ *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
+ *   direction" request is issued (like reading an IN endpoint).
  *
  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
  * not possible on all hardware.  For example, precise fault handling with
@@ -188,7 +188,6 @@ static struct dev_data *dev_new (void)
 enum ep_state {
 	STATE_EP_DISABLED = 0,
 	STATE_EP_READY,
-	STATE_EP_DEFER_ENABLE,
 	STATE_EP_ENABLED,
 	STATE_EP_UNBOUND,
 };
@@ -313,18 +312,10 @@ nonblock:
 
 	if ((val = down_interruptible (&epdata->lock)) < 0)
 		return val;
-newstate:
+
 	switch (epdata->state) {
 	case STATE_EP_ENABLED:
 		break;
-	case STATE_EP_DEFER_ENABLE:
-		DBG (epdata->dev, "%s wait for host\n", epdata->name);
-		if ((val = wait_event_interruptible (epdata->wait, 
-				epdata->state != STATE_EP_DEFER_ENABLE
-				|| epdata->dev->state == STATE_DEV_UNBOUND
-				)) < 0)
-			goto fail;
-		goto newstate;
 	// case STATE_EP_DISABLED:		/* "can't happen" */
 	// case STATE_EP_READY:			/* "can't happen" */
 	default:				/* error! */
@@ -333,7 +324,6 @@ newstate:
 		// FALLTHROUGH
 	case STATE_EP_UNBOUND:			/* clean disconnect */
 		val = -ENODEV;
-fail:
 		up (&epdata->lock);
 	}
 	return val;
@@ -852,9 +842,9 @@ ep_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
 		break;
 #endif
 	default:
-		DBG (data->dev, "unconnected, %s init deferred\n",
+		DBG(data->dev, "unconnected, %s init abandoned\n",
 				data->name);
-		data->state = STATE_EP_DEFER_ENABLE;
+		value = -EINVAL;
 	}
 	if (value == 0) {
 		fd->f_op = &ep_io_operations;
@@ -1393,8 +1383,6 @@ gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
 	spin_lock (&dev->lock);
 	dev->setup_abort = 0;
 	if (dev->state == STATE_UNCONNECTED) {
-		struct usb_ep	*ep;
-		struct ep_data	*data;
 
 		dev->state = STATE_CONNECTED;
 		dev->dev->bMaxPacketSize0 = gadget->ep0->maxpacket;
@@ -1411,27 +1399,6 @@ gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
 		event->u.speed = gadget->speed;
 		ep0_readable (dev);
 
-		list_for_each_entry (ep, &gadget->ep_list, ep_list) {
-			data = ep->driver_data;
-			/* ... down_trylock (&data->lock) ... */
-			if (data->state != STATE_EP_DEFER_ENABLE)
-				continue;
-#ifdef	CONFIG_USB_GADGET_DUALSPEED
-			if (gadget->speed == USB_SPEED_HIGH)
-				value = usb_ep_enable (ep, &data->hs_desc);
-			else
-#endif	/* CONFIG_USB_GADGET_DUALSPEED */
-				value = usb_ep_enable (ep, &data->desc);
-			if (value) {
-				ERROR (dev, "deferred %s enable --> %d\n",
-					data->name, value);
-				continue;
-			}
-			data->state = STATE_EP_ENABLED;
-			wake_up (&data->wait);
-			DBG (dev, "woke up %s waiters\n", data->name);
-		}
-
 	/* host may have given up waiting for response.  we can miss control
 	 * requests handled lower down (device/endpoint status and features);
 	 * then ep0_{read,write} will report the wrong status. controller
@@ -1852,16 +1819,13 @@ static struct usb_gadget_driver probe_driver = {
  *	this one's optional except for high-speed hardware
  * . device descriptor
  *
- * Endpoints are not yet enabled. Drivers may want to immediately
- * initialize them, using the /dev/gadget/ep* files that are available
- * as soon as the kernel sees the configuration, or they can wait
- * until device configuration and interface altsetting changes create
+ * Endpoints are not yet enabled. Drivers must wait until device
+ * configuration and interface altsetting changes create
  * the need to configure (or unconfigure) them.
  *
  * After initialization, the device stays active for as long as that
- * $CHIP file is open.  Events may then be read from that descriptor,
- * such as configuration notifications.  More complex drivers will handle
- * some control requests in user space.
+ * $CHIP file is open.  Events must then be read from that descriptor,
+ * such as configuration notifications.
  */
 
 static int is_valid_config (struct usb_config_descriptor *config)