patch-2.2.18 linux/drivers/char/rtc.c

• Lines: 257
• Date: Sat Oct 28 13:46:20 2000
• Orig file: v2.2.17/drivers/char/rtc.c
• Orig date: Fri Apr 21 12:46:06 2000

diff -u --new-file --recursive --exclude-from /usr/src/exclude v2.2.17/drivers/char/rtc.c linux/drivers/char/rtc.c
@@ -42,10 +42,9 @@
 
 /*
  *	Note that *all* calls to CMOS_READ and CMOS_WRITE are done with
- *	interrupts disabled. Due to the index-port/data-port (0x70/0x71)
- *	design of the RTC, we don't want two different things trying to
- *	get to it at once. (e.g. the periodic 11 min sync from time.c vs.
- *	this driver.)
+ *	the rtc_lock held. Due to the index-port/data-port (0x70/0x71) design 
+ *	of the RTC, we don't want two different things trying to get to it at 
+ *	once. (e.g. the periodic 11 min sync from time.c vs. this driver.)
  */
 
 #include <linux/types.h>
@@ -110,13 +109,15 @@
 
 static unsigned long epoch = 1900;	/* year corresponding to 0x00	*/
 
-unsigned char days_in_mo[] = 
-{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+unsigned char days_in_mo[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
 
 /*
  *	A very tiny interrupt handler. It runs with SA_INTERRUPT set,
- *	so that there is no possibility of conflicting with the
- *	set_rtc_mmss() call that happens during some timer interrupts.
+ *	but there is possibility of conflicting with the set_rtc_mmss()
+ *	call (the rtc irq and the timer irq can easily run at the same
+ *	time in two different CPUs). So we need to serializes
+ *	accesses to the chip with the rtc_lock spinlock that each
+ *	architecture should implement in the timer code.
  *	(See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.)
  */
 
@@ -131,7 +132,10 @@
 
 	rtc_irq_data += 0x100;
 	rtc_irq_data &= ~0xff;
+	/* runs with irq locally disabled (see SA_INTERRUPT flag). */
+	spin_lock(&rtc_lock);
 	rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);
+	spin_unlock(&rtc_lock);
 	wake_up_interruptible(&rtc_wait);	
 
 	if (rtc_status & RTC_TIMER_ON)
@@ -276,8 +280,7 @@
 		if (sec >= 60)
 			sec = 0xff;
 
-		save_flags(flags);
-		cli();
+		spin_lock_irqsave(&rtc_lock, flags);
 		if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) ||
 		    RTC_ALWAYS_BCD)
 		{
@@ -288,7 +291,7 @@
 		CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 		CMOS_WRITE(min, RTC_MINUTES_ALARM);
 		CMOS_WRITE(sec, RTC_SECONDS_ALARM);
-		restore_flags(flags);
+		spin_unlock_irqrestore(&rtc_lock, flags);
 
 		return 0;
 	}
@@ -336,12 +339,11 @@
 		if ((yrs -= epoch) > 255)    /* They are unsigned */
 			return -EINVAL;
 
-		save_flags(flags);
-		cli();
+		spin_lock_irqsave(&rtc_lock, flags);
 		if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
 		    || RTC_ALWAYS_BCD) {
 			if (yrs > 169) {
-				restore_flags(flags);
+				spin_unlock_irqrestore(&rtc_lock, flags);
 				return -EINVAL;
 			}
 			if (yrs >= 100)
@@ -370,7 +372,7 @@
 		CMOS_WRITE(save_control, RTC_CONTROL);
 		CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
 
-		restore_flags(flags);
+		spin_unlock_irqrestore(&rtc_lock, flags);
 		return 0;
 	}
 	case RTC_IRQP_READ:	/* Read the periodic IRQ rate.	*/
@@ -405,12 +407,11 @@
 
 		rtc_freq = arg;
 
-		save_flags(flags);
-		cli();
+		spin_lock_irqsave(&rtc_lock, flags);
 		val = CMOS_READ(RTC_FREQ_SELECT) & 0xf0;
 		val |= (16 - tmp);
 		CMOS_WRITE(val, RTC_FREQ_SELECT);
-		restore_flags(flags);
+		spin_unlock_irqrestore(&rtc_lock, flags);
 		return 0;
 	}
 #ifdef __alpha__
@@ -465,15 +466,14 @@
 	unsigned char tmp;
 	unsigned long flags;
 
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&rtc_lock, flags);
 	tmp = CMOS_READ(RTC_CONTROL);
 	tmp &=  ~RTC_PIE;
 	tmp &=  ~RTC_AIE;
 	tmp &=  ~RTC_UIE;
 	CMOS_WRITE(tmp, RTC_CONTROL);
 	CMOS_READ(RTC_INTR_FLAGS);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&rtc_lock, flags);
 
 	if (rtc_status & RTC_TIMER_ON) {
 		rtc_status &= ~RTC_TIMER_ON;
@@ -546,11 +546,10 @@
 		while (jiffies - uip_watchdog < 2*HZ/100)
 			barrier();
 	
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&rtc_lock, flags);
 	year = CMOS_READ(RTC_YEAR);
 	ctrl = CMOS_READ(RTC_CONTROL);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&rtc_lock, flags);
 	
 	if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
 		BCD_TO_BIN(year);       /* This should never happen... */
@@ -568,11 +567,10 @@
 	init_timer(&rtc_irq_timer);
 	rtc_irq_timer.function = rtc_dropped_irq;
 	rtc_wait = NULL;
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&rtc_lock, flags);
 	/* Initialize periodic freq. to CMOS reset default, which is 1024Hz */
 	CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT) & 0xF0) | 0x06), RTC_FREQ_SELECT);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&rtc_lock, flags);
 	rtc_freq = 1024;
 	return 0;
 }
@@ -596,12 +594,11 @@
 	printk(KERN_INFO "rtc: lost some interrupts at %ldHz.\n", rtc_freq);
 	mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);
 
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&rtc_lock, flags);
 	rtc_irq_data += ((rtc_freq/HZ)<<8);
 	rtc_irq_data &= ~0xff;
 	rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);	/* restart */
-	restore_flags(flags);
+	spin_unlock_irqrestore(&rtc_lock, flags);
 }
 
 /*
@@ -615,11 +612,10 @@
 	unsigned char batt, ctrl;
 	unsigned long flags;
 
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&rtc_lock, flags);
 	batt = CMOS_READ(RTC_VALID) & RTC_VRT;
 	ctrl = CMOS_READ(RTC_CONTROL);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&rtc_lock, flags);
 
 	p = buf;
 
@@ -690,10 +686,9 @@
 	unsigned long flags;
 	unsigned char uip;
 
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&rtc_lock, flags);
 	uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&rtc_lock, flags);
 	return uip;
 }
 
@@ -723,8 +718,7 @@
 	 * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
 	 * by the RTC when initially set to a non-zero value.
 	 */
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&rtc_lock, flags);
 	rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
 	rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
 	rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
@@ -732,7 +726,7 @@
 	rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
 	rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
 	ctrl = CMOS_READ(RTC_CONTROL);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&rtc_lock, flags);
 
 	if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
 	{
@@ -763,13 +757,12 @@
 	 * Only the values that we read from the RTC are set. That
 	 * means only tm_hour, tm_min, and tm_sec.
 	 */
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&rtc_lock, flags);
 	alm_tm->tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 	alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 	alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 	ctrl = CMOS_READ(RTC_CONTROL);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&rtc_lock, flags);
 
 	if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
 	{
@@ -794,13 +787,12 @@
 	unsigned char val;
 	unsigned long flags;
 
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&rtc_lock, flags);
 	val = CMOS_READ(RTC_CONTROL);
 	val &=  ~bit;
 	CMOS_WRITE(val, RTC_CONTROL);
 	CMOS_READ(RTC_INTR_FLAGS);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&rtc_lock, flags);
 	rtc_irq_data = 0;
 }
 
@@ -809,12 +801,11 @@
 	unsigned char val;
 	unsigned long flags;
 
-	save_flags(flags);
-	cli();
+	spin_lock_irqsave(&rtc_lock, flags);
 	val = CMOS_READ(RTC_CONTROL);
 	val |= bit;
 	CMOS_WRITE(val, RTC_CONTROL);
 	CMOS_READ(RTC_INTR_FLAGS);
 	rtc_irq_data = 0;
-	restore_flags(flags);
+	spin_unlock_irqrestore(&rtc_lock, flags);
 }