From: Haavard Skinnemoen <hskinnemoen@atmel.com>
Date: Fri, 8 Feb 2008 12:21:02 +0000 (-0800)
Subject: atmel_serial: use cpu_relax() when busy-waiting
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=829dd8112274d46c5ed82d46be506762e2c8fcd8;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

atmel_serial: use cpu_relax() when busy-waiting

Replace two instances of barrier() with cpu_relax() since that's the right
thing to do when busy-waiting.  This does not actually change anything since
cpu_relax() is defined as barrier() on both ARM and AVR32.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: Andrew Victor <linux@maxim.org.za>
Tested-by: Marc Pignat <marc.pignat@hevs.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c
index bb9c3574caa9..4d1ccc2b762d 100644
--- a/drivers/serial/atmel_serial.c
+++ b/drivers/serial/atmel_serial.c
@@ -615,7 +615,7 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
 	imr = UART_GET_IMR(port);
 	UART_PUT_IDR(port, -1);
 	while (!(UART_GET_CSR(port) & ATMEL_US_TXEMPTY))
-		barrier();
+		cpu_relax();
 
 	/* disable receiver and transmitter */
 	UART_PUT_CR(port, ATMEL_US_TXDIS | ATMEL_US_RXDIS);
@@ -794,7 +794,7 @@ void __init atmel_register_uart_fns(struct atmel_port_fns *fns)
 static void atmel_console_putchar(struct uart_port *port, int ch)
 {
 	while (!(UART_GET_CSR(port) & ATMEL_US_TXRDY))
-		barrier();
+		cpu_relax();
 	UART_PUT_CHAR(port, ch);
 }