usb: dwc3: Wait for EndXfer completion before restoring GUSB2PHYCFG

DWC3 programming guide mentions that when operating in USB2.0 speeds,
if GUSB2PHYCFG[6] or GUSB2PHYCFG[8] is set, it must be cleared prior
to issuing commands and may be set again  after the command completes.
But currently while issuing EndXfer command without CmdIOC set, we
wait for 1ms after GUSB2PHYCFG is restored. This results in cases
where EndXfer command doesn't get completed and causes SMMU faults
since requests are unmapped afterwards. Hence restore GUSB2PHYCFG
after waiting for EndXfer command completion.

Cc: [email protected]
Fixes: 1d26ba0 ("usb: dwc3: Wait unconditionally after issuing EndXfer command")
Signed-off-by: Prashanth K <[email protected]>
Acked-by: Thinh Nguyen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Prashanth K

drivers/usb/dwc3/gadget.c

@@ -438,6 +438,10 @@ int dwc3_send_gadget_ep_cmd(struct dwc3_ep *dep, unsigned int cmd,
 			dwc3_gadget_ep_get_transfer_index(dep);
 	}
 
+	if (DWC3_DEPCMD_CMD(cmd) == DWC3_DEPCMD_ENDTRANSFER &&
+	    !(cmd & DWC3_DEPCMD_CMDIOC))
+		mdelay(1);
+
 	if (saved_config) {
 		reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
 		reg |= saved_config;
@@ -1715,12 +1719,10 @@ static int __dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force, bool int
 	WARN_ON_ONCE(ret);
 	dep->resource_index = 0;
 
-	if (!interrupt) {
-		mdelay(1);
+	if (!interrupt)
 		dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
-	} else if (!ret) {
+	else if (!ret)
 		dep->flags |= DWC3_EP_END_TRANSFER_PENDING;
-	}
 
 	dep->flags &= ~DWC3_EP_DELAY_STOP;
 	return ret;