usb: gadget: f_fs: preserve wMaxPacketSize across usb_ep_autoconfig() call

usb_ep_autoconfig() treats the passed descriptor as if it were an fs
descriptor. In particular, for bulk endpoints, it clips wMaxPacketSize
to 64. This patch preserves the original value.
Signed-off-by: NAndrzej Pietrasiewicz <andrzej.p@collabora.com>
Signed-off-by: NFelipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/gadget/function/f_fs.c

@@ -2843,12 +2843,18 @@ static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
 		struct usb_request *req;
 		struct usb_ep *ep;
 		u8 bEndpointAddress;
+		u16 wMaxPacketSize;
 
 		/*
 		 * We back up bEndpointAddress because autoconfig overwrites
 		 * it with physical endpoint address.
 		 */
 		bEndpointAddress = ds->bEndpointAddress;
+		/*
+		 * We back up wMaxPacketSize because autoconfig treats
+		 * endpoint descriptors as if they were full speed.
+		 */
+		wMaxPacketSize = ds->wMaxPacketSize;
 		pr_vdebug("autoconfig\n");
 		ep = usb_ep_autoconfig(func->gadget, ds);
 		if (unlikely(!ep))
@@ -2869,6 +2875,11 @@ static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
 		 */
 		if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
 			ds->bEndpointAddress = bEndpointAddress;
+		/*
+		 * Restore wMaxPacketSize which was potentially
+		 * overwritten by autoconfig.
+		 */
+		ds->wMaxPacketSize = wMaxPacketSize;
 	}
 	ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);