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>

1 files changed, 11 insertions, 2 deletions

diff --git a/drivers/usb/renesas_usbhs/fifo.c b/drivers/usb/renesas_usbhs/fifo.c
index 03cac07f57b5..68f26904c316 100644
--- 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