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>

2 files changed, 13 insertions, 0 deletions

diff --git a/arch/mips/sibyte/swarm/rtc_m41t81.c b/arch/mips/sibyte/swarm/rtc_m41t81.c
index 5b4fc26c1b36..c13914bdda59 100644
--- a/arch/mips/sibyte/swarm/rtc_m41t81.c
+++ b/arch/mips/sibyte/swarm/rtc_m41t81.c
@@ -144,6 +144,7 @@ static int m41t81_write(uint8_t addr, int b)
 int m41t81_set_time(unsigned long t)
 {
 	struct rtc_time tm;
+	unsigned long flags;
 
 	to_tm(t, &tm);
 
@@ -153,6 +154,7 @@ int m41t81_set_time(unsigned long t)
 	 * 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 @@ int m41t81_set_time(unsigned long t)
 	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 @@ int m41t81_set_time(unsigned long t)
 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);
diff --git a/arch/mips/sibyte/swarm/rtc_xicor1241.c b/arch/mips/sibyte/swarm/rtc_xicor1241.c
index d9ff9323f24e..f4a178836415 100644
--- a/arch/mips/sibyte/swarm/rtc_xicor1241.c
+++ b/arch/mips/sibyte/swarm/rtc_xicor1241.c
@@ -113,9 +113,11 @@ int xicor_set_time(unsigned long t)
 {
 	struct rtc_time tm;
 	int tmp;
+	unsigned long flags;
 
 	to_tm(t, &tm);
 
+	spin_lock_irqsave(&rtc_lock, flags);
 	/* unlock writes to the CCR */
 	xicor_write(X1241REG_SR, X1241REG_SR_WEL);
 	xicor_write(X1241REG_SR, X1241REG_SR_WEL | X1241REG_SR_RWEL);
@@ -160,6 +162,7 @@ int xicor_set_time(unsigned long t)
 	xicor_write(X1241REG_HR, tmp);
 
 	xicor_write(X1241REG_SR, 0);
+	spin_unlock_irqrestore(&rtc_lock, flags);
 
 	return 0;
 }
@@ -167,7 +170,9 @@ int xicor_set_time(unsigned long t)
 unsigned long xicor_get_time(void)
 {
 	unsigned int year, mon, day, hour, min, sec, y2k;
+	unsigned long flags;
 
+	spin_lock_irqsave(&rtc_lock, flags);
 	sec = xicor_read(X1241REG_SC);
 	min = xicor_read(X1241REG_MN);
 	hour = xicor_read(X1241REG_HR);
@@ -183,6 +188,7 @@ unsigned long xicor_get_time(void)
 	mon = xicor_read(X1241REG_MO);
 	year = xicor_read(X1241REG_YR);
 	y2k = xicor_read(X1241REG_Y2K);
+	spin_unlock_irqrestore(&rtc_lock, flags);
 
 	sec = BCD2BIN(sec);
 	min = BCD2BIN(min);