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Subject[PATCH -mm v4 3/9] atmel_serial: Use cpu_relax() when busy-waiting
Date
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>
---
drivers/serial/atmel_serial.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c
index ee5d844..4b5c6ff 100644
--- a/drivers/serial/atmel_serial.c
+++ b/drivers/serial/atmel_serial.c
@@ -616,7 +616,7 @@ 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);
@@ -795,7 +795,7 @@ 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);
}

--
1.5.3.8


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