[PATCH] USB: Add OTG support to g_file_storage

This patch adds minimal USB On-The-Go support (mainly just an extra
descriptor) to the File-Storage Gadget.  The changes were based on the
additions made to the Gadget Zero driver.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/usb/gadget/file_storage.c

@@ -248,7 +248,7 @@
 
 #define DRIVER_DESC		"File-backed Storage Gadget"
 #define DRIVER_NAME		"g_file_storage"
-#define DRIVER_VERSION		"28 July 2004"
+#define DRIVER_VERSION		"31 August 2004"
 
 static const char longname[] = DRIVER_DESC;
 static const char shortname[] = DRIVER_NAME;
@@ -866,6 +866,14 @@ config_desc = {
 	.bMaxPower =		1,	// self-powered
 };
 
+static struct usb_otg_descriptor
+otg_desc = {
+	.bLength =		sizeof(otg_desc),
+	.bDescriptorType =	USB_DT_OTG,
+
+	.bmAttributes =		USB_OTG_SRP,
+};
+
 /* There is only one interface. */
 
 static struct usb_interface_descriptor
@@ -914,6 +922,7 @@ fs_intr_in_desc = {
 };
 
 static const struct usb_descriptor_header *fs_function[] = {
+	(struct usb_descriptor_header *) &otg_desc,
 	(struct usb_descriptor_header *) &intf_desc,
 	(struct usb_descriptor_header *) &fs_bulk_in_desc,
 	(struct usb_descriptor_header *) &fs_bulk_out_desc,
@@ -976,6 +985,7 @@ hs_intr_in_desc = {
 };
 
 static const struct usb_descriptor_header *hs_function[] = {
+	(struct usb_descriptor_header *) &otg_desc,
 	(struct usb_descriptor_header *) &intf_desc,
 	(struct usb_descriptor_header *) &hs_bulk_in_desc,
 	(struct usb_descriptor_header *) &hs_bulk_out_desc,
@@ -1018,9 +1028,10 @@ static struct usb_gadget_strings	stringtab = {
  * and with code managing interfaces and their altsettings.  They must
  * also handle different speeds and other-speed requests.
  */
-static int populate_config_buf(enum usb_device_speed speed,
+static int populate_config_buf(struct usb_gadget *gadget,
 		u8 *buf, u8 type, unsigned index)
 {
+	enum usb_device_speed			speed = gadget->speed;
 	int					len;
 	const struct usb_descriptor_header	**function;
 
@@ -1036,6 +1047,10 @@ static int populate_config_buf(enum usb_device_speed speed,
 #endif
 		function = fs_function;
 
+	/* for now, don't advertise srp-only devices */
+	if (!gadget->is_otg)
+		function++;
+
 	len = usb_gadget_config_buf(&config_desc, buf, EP0_BUFSIZE, function);
 	((struct usb_config_descriptor *) buf)->bDescriptorType = type;
 	return len;
@@ -1366,7 +1381,7 @@ static int standard_setup_req(struct fsg_dev *fsg,
 #ifdef CONFIG_USB_GADGET_DUALSPEED
 		get_config:
 #endif
-			value = populate_config_buf(fsg->gadget->speed,
+			value = populate_config_buf(fsg->gadget,
 					req->buf,
 					ctrl->wValue >> 8,
 					ctrl->wValue & 0xff);
@@ -3896,6 +3911,11 @@ static int __init fsg_bind(struct usb_gadget *gadget)
 	hs_intr_in_desc.bEndpointAddress = fs_intr_in_desc.bEndpointAddress;
 #endif
 
+	if (gadget->is_otg) {
+		otg_desc.bmAttributes |= USB_OTG_HNP,
+		config_desc.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+	}
+
 	rc = -ENOMEM;
 
 	/* Allocate the request and buffer for endpoint 0 */