linux-kernel - [PATCH 3/3] serial: samsung: Change barrier() to cpu

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Date:	Mon, 21 Apr 2014 09:40:36 -0700
From:	Doug Anderson <dianders@...omium.org>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-samsung-soc@...r.kernel.org
Cc:	olof@...om.net, Doug Anderson <dianders@...omium.org>,
	jslaby@...e.cz, linux-serial@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] serial: samsung: Change barrier() to cpu_relax() in console output

The two functions to write out to the console (one used in normal
console mode and one in polling console mode) were slightly different.
One used a barrier() in its loop and the other a cpu_relax().  The
barrier() really doesn't do anything since we're using rd_regl() to
read the port anyway.  Switch it to cpu_relax() to make things
consistent.

No known bugs / issues are fixed by this change--it just makes things
more consistent.

Signed-off-by: Doug Anderson <dianders@...omium.org>
---
 drivers/tty/serial/samsung.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
index 12442748..1f5505e 100644
--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -1466,7 +1466,7 @@ s3c24xx_serial_console_putchar(struct uart_port *port, int ch)
 	unsigned int ufcon = rd_regl(port, S3C2410_UFCON);
 
 	while (!s3c24xx_serial_console_txrdy(port, ufcon))
-		barrier();
+		cpu_relax();
 	wr_regb(port, S3C2410_UTXH, ch);
 }
 
-- 
1.9.1.423.g4596e3a

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