usb: renesas_usbhs: fix usbhsf_fifo_clear() for RX direction

This patch fixes an issue that the usbhsf_fifo_clear() is possible
to cause 10 msec delay if the pipe is RX direction and empty because
the FRDY bit will never be set to 1 in such case.

Fixes: e8d548d ("usb: renesas_usbhs: fifo became independent from pipe.")
Cc: <[email protected]> # v3.1+
Signed-off-by: Yoshihiro Shimoda <[email protected]>
Signed-off-by: Felipe Balbi <[email protected]>

Author: shimoday

drivers/usb/renesas_usbhs/fifo.c

@@ -284,8 +284,17 @@ static void usbhsf_fifo_clear(struct usbhs_pipe *pipe,
 	struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
 	int ret = 0;
 
-	if (!usbhs_pipe_is_dcp(pipe))
-		ret = usbhsf_fifo_barrier(priv, fifo);
+	if (!usbhs_pipe_is_dcp(pipe)) {
+		/*
+		 * This driver checks the pipe condition first to avoid -EBUSY
+		 * from usbhsf_fifo_barrier() with about 10 msec delay in
+		 * the interrupt handler if the pipe is RX direction and empty.
+		 */
+		if (usbhs_pipe_is_dir_in(pipe))
+			ret = usbhs_pipe_is_accessible(pipe);
+		if (!ret)
+			ret = usbhsf_fifo_barrier(priv, fifo);
+	}
 
 	/*
 	 * if non-DCP pipe, this driver should set BCLR when