Use rtc_lock to protect RTC operations

    
Many RTC routines were not protected against each other, so there are
potential races, for example, ntp-update against /dev/rtc.  This patch
fixes them using rtc_lock.
    
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/arch/mips/lasat/ds1603.c b/arch/mips/lasat/ds1603.c
index 9d7812e03dcd..7dced67c55eb 100644
--- a/arch/mips/lasat/ds1603.c
+++ b/arch/mips/lasat/ds1603.c
@@ -8,6 +8,7 @@
 #include <asm/lasat/lasat.h>
 #include <linux/delay.h>
 #include <asm/lasat/ds1603.h>
+#include <asm/time.h>
 
 #include "ds1603.h"
 
@@ -138,19 +139,27 @@ static void rtc_end_op(void)
 unsigned long ds1603_read(void)
 {
 	unsigned long word;
+	unsigned long flags;
+
+	spin_lock_irqsave(&rtc_lock, flags);
 	rtc_init_op();
 	rtc_write_byte(READ_TIME_CMD);
 	word = rtc_read_word();
 	rtc_end_op();
+	spin_unlock_irqrestore(&rtc_lock, flags);
 	return word;
 }
 
 int ds1603_set(unsigned long time)
 {
+	unsigned long flags;
+
+	spin_lock_irqsave(&rtc_lock, flags);
 	rtc_init_op();
 	rtc_write_byte(SET_TIME_CMD);
 	rtc_write_word(time);
 	rtc_end_op();
+	spin_unlock_irqrestore(&rtc_lock, flags);
 
 	return 0;
 }