usb: dwc3: gadget: properly check ep cmd

The cmd argument we pass to
dwc3_send_gadget_ep_cmd() could contain extra
arguments embedded. When checking for StartTransfer
command, we need to make sure to match only lower 4
bits which contain the actual command and ignore the
rest.
Reported-by: Janusz Dziedzic <januszx.dziedzic@intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/core.h

@@ -450,6 +450,8 @@
 #define DWC3_DEPCMD_SETTRANSFRESOURCE	(0x02 << 0)
 #define DWC3_DEPCMD_SETEPCONFIG		(0x01 << 0)
 
+#define DWC3_DEPCMD_CMD(x)		((x) & 0xf)
+
 /* The EP number goes 0..31 so ep0 is always out and ep1 is always in */
 #define DWC3_DALEPENA_EP(n)		(1 << n)
 

drivers/usb/dwc3/gadget.c

@@ -258,7 +258,7 @@ int dwc3_send_gadget_ep_cmd(struct dwc3_ep *dep, unsigned cmd,
 		}
 	}
 
-	if (cmd == DWC3_DEPCMD_STARTTRANSFER) {
+	if (DWC3_DEPCMD_CMD(cmd) == DWC3_DEPCMD_STARTTRANSFER) {
 		int		needs_wakeup;
 
 		needs_wakeup = (dwc->link_state == DWC3_LINK_STATE_U1 ||