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: e8d548d54968 ("usb: renesas_usbhs: fifo became independent from pipe.")
Cc: <stable@vger.kernel.org> # v3.1+
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

diff --git a/drivers/usb/renesas_usbhs/fifo.c b/drivers/usb/renesas_usbhs/fifo.c
index 03cac07..68f2690 100644 (file)
--- a/drivers/usb/renesas_usbhs/fifo.c
+++ b/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