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>
diff --git a/arch/mips/sibyte/swarm/rtc_m41t81.c b/arch/mips/sibyte/swarm/rtc_m41t81.c
index 5b4fc26..c13914b 100644
--- a/arch/mips/sibyte/swarm/rtc_m41t81.c
+++ b/arch/mips/sibyte/swarm/rtc_m41t81.c
@@ -144,6 +144,7 @@
int m41t81_set_time(unsigned long t)
{
struct rtc_time tm;
+ unsigned long flags;
to_tm(t, &tm);
@@ -153,6 +154,7 @@
* believe we should finish writing min within a second.
*/
+ spin_lock_irqsave(&rtc_lock, flags);
tm.tm_sec = BIN2BCD(tm.tm_sec);
m41t81_write(M41T81REG_SC, tm.tm_sec);
@@ -180,6 +182,7 @@
tm.tm_year %= 100;
tm.tm_year = BIN2BCD(tm.tm_year);
m41t81_write(M41T81REG_YR, tm.tm_year);
+ spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
@@ -187,19 +190,23 @@
unsigned long m41t81_get_time(void)
{
unsigned int year, mon, day, hour, min, sec;
+ unsigned long flags;
/*
* min is valid if two reads of sec are the same.
*/
for (;;) {
+ spin_lock_irqsave(&rtc_lock, flags);
sec = m41t81_read(M41T81REG_SC);
min = m41t81_read(M41T81REG_MN);
if (sec == m41t81_read(M41T81REG_SC)) break;
+ spin_unlock_irqrestore(&rtc_lock, flags);
}
hour = m41t81_read(M41T81REG_HR) & 0x3f;
day = m41t81_read(M41T81REG_DT);
mon = m41t81_read(M41T81REG_MO);
year = m41t81_read(M41T81REG_YR);
+ spin_unlock_irqrestore(&rtc_lock, flags);
sec = BCD2BIN(sec);
min = BCD2BIN(min);