[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20090324140257.12735.75468.stgit@localhost.localdomain>
Date: Tue, 24 Mar 2009 14:03:07 +0000
From: Alan Cox <alan@...rguk.ukuu.org.uk>
To: linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
torvalds@...ux-foundation.org
Subject: [PATCH 08/30] Use barrier instead of cpu_relax for early blackfin boot
From: Graf Yang <graf.yang@...log.com>
We are making a SMP like patch to blackfin, cpu_relax() is replaced by a
data cache flush function which will count it to a per-cpu counter.
If this serial function is called too early, the per-cpu data area have
not been initialized, this call will cause crash.
So we'd like to use barrier() instead of cpu_relax().
Signed-off-by: Graf Yang <graf.yang@...log.com>
Signed-off-by: Bryan Wu <cooloney@...nel.org>
Signed-off-by: Alan Cox <alan@...rguk.ukuu.org.uk>
---
drivers/serial/bfin_5xx.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index 318d69d..d46d764 100644
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -1128,7 +1128,8 @@ static __init void early_serial_putc(struct uart_port *port, int ch)
struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
while ((!(UART_GET_LSR(uart) & THRE)) && --timeout)
- cpu_relax();
+ barrier();
+
UART_PUT_CHAR(uart, ch);
}
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists