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patch "usb: renesas_usbhs: fix usbhsf_fifo_clear() for RX direction" added to usb-linus

PATCH [email protected] 1 participant 1 message Sep 29, 2017

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This is a note to let you know that I've just added the patch titled

usb: renesas_usbhs: fix usbhsf_fifo_clear() for RX direction

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

Quoted 1 line

From 0a2ce62b61f2c76d0213edf4e37aaf54a8ddf295 Mon Sep 17 00:00:00 2001

From: Yoshihiro Shimoda <[email protected]>
Date: Wed, 27 Sep 2017 18:47:13 +0900
Subject: 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 <[email protected]> # v3.1+
---
 drivers/usb/renesas_usbhs/fifo.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)
drivers/usb/renesas_usbhs/fifo.c +11 -2
index 03cac07f57b5..68f26904c316 100644
@@ -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
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