x86: share rtc code

Remove the rtc code from time_64.c and add the extra bits to the
i386 path. The ACPI century check is probably valid for i386 as
well, but this is material for a separate patch.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/Makefile_64

@@ -11,7 +11,7 @@ obj-y	:= process_64.o signal_64.o entry_64.o traps_64.o irq_64.o \
 		x8664_ksyms_64.o i387_64.o syscall_64.o vsyscall_64.o \
 		setup64.o bootflag.o e820_64.o reboot_64.o quirks.o i8237.o \
 		pci-dma_64.o pci-nommu_64.o alternative.o hpet.o tsc_64.o bugs_64.o \
-		i8253.o io_delay.o
+		i8253.o io_delay.o rtc.o
 
 obj-$(CONFIG_STACKTRACE)	+= stacktrace.o
 obj-y				+= cpu/

arch/x86/kernel/rtc.c

@@ -1,11 +1,32 @@
 /*
  * RTC related functions
  */
+#include <linux/acpi.h>
 #include <linux/bcd.h>
 #include <linux/mc146818rtc.h>
 
 #include <asm/time.h>
 
+#ifdef CONFIG_X86_32
+# define CMOS_YEARS_OFFS 1900
+/*
+ * This is a special lock that is owned by the CPU and holds the index
+ * register we are working with.  It is required for NMI access to the
+ * CMOS/RTC registers.  See include/asm-i386/mc146818rtc.h for details.
+ */
+volatile unsigned long cmos_lock = 0;
+EXPORT_SYMBOL(cmos_lock);
+#else
+/*
+ * x86-64 systems only exists since 2002.
+ * This will work up to Dec 31, 2100
+ */
+# define CMOS_YEARS_OFFS 2000
+#endif
+
+DEFINE_SPINLOCK(rtc_lock);
+EXPORT_SYMBOL(rtc_lock);
+
 /*
  * In order to set the CMOS clock precisely, set_rtc_mmss has to be
  * called 500 ms after the second nowtime has started, because when
@@ -22,10 +43,12 @@ int mach_set_rtc_mmss(unsigned long nowtime)
 	int real_seconds, real_minutes, cmos_minutes;
 	unsigned char save_control, save_freq_select;
 
-	save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */
+	 /* tell the clock it's being set */
+	save_control = CMOS_READ(RTC_CONTROL);
 	CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
 
-	save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */
+	/* stop and reset prescaler */
+	save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
 	CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
 
 	cmos_minutes = CMOS_READ(RTC_MINUTES);
@@ -40,8 +63,9 @@ int mach_set_rtc_mmss(unsigned long nowtime)
 	 */
 	real_seconds = nowtime % 60;
 	real_minutes = nowtime / 60;
+	/* correct for half hour time zone */
 	if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
-		real_minutes += 30;		/* correct for half hour time zone */
+		real_minutes += 30;
 	real_minutes %= 60;
 
 	if (abs(real_minutes - cmos_minutes) < 30) {
@@ -73,18 +97,32 @@ int mach_set_rtc_mmss(unsigned long nowtime)
 
 unsigned long mach_get_cmos_time(void)
 {
-	unsigned int year, mon, day, hour, min, sec;
-
-	do {
-		sec = CMOS_READ(RTC_SECONDS);
-		min = CMOS_READ(RTC_MINUTES);
-		hour = CMOS_READ(RTC_HOURS);
-		day = CMOS_READ(RTC_DAY_OF_MONTH);
-		mon = CMOS_READ(RTC_MONTH);
-		year = CMOS_READ(RTC_YEAR);
-	} while (sec != CMOS_READ(RTC_SECONDS));
-
-	if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+	unsigned int year, mon, day, hour, min, sec, century = 0;
+
+	/*
+	 * If UIP is clear, then we have >= 244 microseconds before
+	 * RTC registers will be updated.  Spec sheet says that this
+	 * is the reliable way to read RTC - registers. If UIP is set
+	 * then the register access might be invalid.
+	 */
+	while ((CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
+		cpu_relax();
+
+	sec = CMOS_READ(RTC_SECONDS);
+	min = CMOS_READ(RTC_MINUTES);
+	hour = CMOS_READ(RTC_HOURS);
+	day = CMOS_READ(RTC_DAY_OF_MONTH);
+	mon = CMOS_READ(RTC_MONTH);
+	year = CMOS_READ(RTC_YEAR);
+
+#if defined(CONFIG_ACPI) && defined(CONFIG_X86_64)
+	/* CHECKME: Is this really 64bit only ??? */
+	if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
+	    acpi_gbl_FADT.century)
+		century = CMOS_READ(acpi_gbl_FADT.century);
+#endif
+
+	if (RTC_ALWAYS_BCD || !(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)) {
 		BCD_TO_BIN(sec);
 		BCD_TO_BIN(min);
 		BCD_TO_BIN(hour);
@@ -93,24 +131,19 @@ unsigned long mach_get_cmos_time(void)
 		BCD_TO_BIN(year);
 	}
 
-	year += 1900;
-	if (year < 1970)
-		year += 100;
+	if (century) {
+		BCD_TO_BIN(century);
+		year += century * 100;
+		printk(KERN_INFO "Extended CMOS year: %d\n", century * 100);
+	} else {
+		year += CMOS_YEARS_OFFS;
+		if (year < 1970)
+			year += 100;
+	}
 
 	return mktime(year, mon, day, hour, min, sec);
 }
 
-DEFINE_SPINLOCK(rtc_lock);
-EXPORT_SYMBOL(rtc_lock);
-
-/*
- * This is a special lock that is owned by the CPU and holds the index
- * register we are working with.  It is required for NMI access to the
- * CMOS/RTC registers.  See include/asm-i386/mc146818rtc.h for details.
- */
-volatile unsigned long cmos_lock = 0;
-EXPORT_SYMBOL(cmos_lock);
-
 /* Routines for accessing the CMOS RAM/RTC. */
 unsigned char rtc_cmos_read(unsigned char addr)
 {
@@ -138,8 +171,6 @@ static int set_rtc_mmss(unsigned long nowtime)
 	int retval;
 	unsigned long flags;
 
-	/* gets recalled with irq locally disabled */
-	/* XXX - does irqsave resolve this? -johnstul */
 	spin_lock_irqsave(&rtc_lock, flags);
 	retval = set_wallclock(nowtime);
 	spin_unlock_irqrestore(&rtc_lock, flags);
@@ -150,8 +181,7 @@ static int set_rtc_mmss(unsigned long nowtime)
 /* not static: needed by APM */
 unsigned long read_persistent_clock(void)
 {
-	unsigned long retval;
-	unsigned long flags;
+	unsigned long retval, flags;
 
 	spin_lock_irqsave(&rtc_lock, flags);
 	retval = get_wallclock();

arch/x86/kernel/time_64.c

@@ -46,9 +46,6 @@
 #include <asm/nmi.h>
 #include <asm/vgtod.h>
 
-DEFINE_SPINLOCK(rtc_lock);
-EXPORT_SYMBOL(rtc_lock);
-
 volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES;
 
 unsigned long profile_pc(struct pt_regs *regs)
@@ -69,103 +66,6 @@ unsigned long profile_pc(struct pt_regs *regs)
 }
 EXPORT_SYMBOL(profile_pc);
 
-/* Routines for accessing the CMOS RAM/RTC. */
-unsigned char rtc_cmos_read(unsigned char addr)
-{
-	unsigned char val;
-	lock_cmos_prefix(addr);
-	outb_p(addr, RTC_PORT(0));
-	val = inb_p(RTC_PORT(1));
-	lock_cmos_suffix(addr);
-	return val;
-}
-EXPORT_SYMBOL(rtc_cmos_read);
-
-void rtc_cmos_write(unsigned char val, unsigned char addr)
-{
-	lock_cmos_prefix(addr);
-	outb_p(addr, RTC_PORT(0));
-	outb_p(val, RTC_PORT(1));
-	lock_cmos_suffix(addr);
-}
-EXPORT_SYMBOL(rtc_cmos_write);
-
-/*
- * In order to set the CMOS clock precisely, set_rtc_mmss has to be called 500
- * ms after the second nowtime has started, because when nowtime is written
- * into the registers of the CMOS clock, it will jump to the next second
- * precisely 500 ms later. Check the Motorola MC146818A or Dallas DS12887 data
- * sheet for details.
- */
-
-static int set_rtc_mmss(unsigned long nowtime)
-{
-	int retval = 0;
-	int real_seconds, real_minutes, cmos_minutes;
-	unsigned char control, freq_select;
-	unsigned long flags;
-
-/*
- * set_rtc_mmss is called when irqs are enabled, so disable irqs here
- */
-	spin_lock_irqsave(&rtc_lock, flags);
-/*
- * Tell the clock it's being set and stop it.
- */
-	control = CMOS_READ(RTC_CONTROL);
-	CMOS_WRITE(control | RTC_SET, RTC_CONTROL);
-
-	freq_select = CMOS_READ(RTC_FREQ_SELECT);
-	CMOS_WRITE(freq_select | RTC_DIV_RESET2, RTC_FREQ_SELECT);
-
-	cmos_minutes = CMOS_READ(RTC_MINUTES);
-		BCD_TO_BIN(cmos_minutes);
-
-/*
- * since we're only adjusting minutes and seconds, don't interfere with hour
- * overflow. This avoids messing with unknown time zones but requires your RTC
- * not to be off by more than 15 minutes. Since we're calling it only when
- * our clock is externally synchronized using NTP, this shouldn't be a problem.
- */
-
-	real_seconds = nowtime % 60;
-	real_minutes = nowtime / 60;
-	if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1)
-		real_minutes += 30;		/* correct for half hour time zone */
-	real_minutes %= 60;
-
-	if (abs(real_minutes - cmos_minutes) >= 30) {
-		printk(KERN_WARNING "time.c: can't update CMOS clock "
-		       "from %d to %d\n", cmos_minutes, real_minutes);
-		retval = -1;
-	} else {
-		BIN_TO_BCD(real_seconds);
-		BIN_TO_BCD(real_minutes);
-		CMOS_WRITE(real_seconds, RTC_SECONDS);
-		CMOS_WRITE(real_minutes, RTC_MINUTES);
-	}
-
-/*
- * The following flags have to be released exactly in this order, otherwise the
- * DS12887 (popular MC146818A clone with integrated battery and quartz) will
- * not reset the oscillator and will not update precisely 500 ms later. You
- * won't find this mentioned in the Dallas Semiconductor data sheets, but who
- * believes data sheets anyway ... -- Markus Kuhn
- */
-
-	CMOS_WRITE(control, RTC_CONTROL);
-	CMOS_WRITE(freq_select, RTC_FREQ_SELECT);
-
-	spin_unlock_irqrestore(&rtc_lock, flags);
-
-	return retval;
-}
-
-int update_persistent_clock(struct timespec now)
-{
-	return set_rtc_mmss(now.tv_sec);
-}
-
 static irqreturn_t timer_event_interrupt(int irq, void *dev_id)
 {
 	add_pda(irq0_irqs, 1);
@@ -175,63 +75,6 @@ static irqreturn_t timer_event_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-unsigned long read_persistent_clock(void)
-{
-	unsigned int year, mon, day, hour, min, sec;
-	unsigned long flags;
-	unsigned century = 0;
-
-	spin_lock_irqsave(&rtc_lock, flags);
-	/*
-	 * if UIP is clear, then we have >= 244 microseconds before RTC
-	 * registers will be updated.  Spec sheet says that this is the
-	 * reliable way to read RTC - registers invalid (off bus) during update
-	 */
-	while ((CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
-		cpu_relax();
-
-
-	/* now read all RTC registers while stable with interrupts disabled */
-	sec = CMOS_READ(RTC_SECONDS);
-	min = CMOS_READ(RTC_MINUTES);
-	hour = CMOS_READ(RTC_HOURS);
-	day = CMOS_READ(RTC_DAY_OF_MONTH);
-	mon = CMOS_READ(RTC_MONTH);
-	year = CMOS_READ(RTC_YEAR);
-#ifdef CONFIG_ACPI
-	if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
-				acpi_gbl_FADT.century)
-		century = CMOS_READ(acpi_gbl_FADT.century);
-#endif
-	spin_unlock_irqrestore(&rtc_lock, flags);
-
-	/*
-	 * We know that x86-64 always uses BCD format, no need to check the
-	 * config register.
-	 */
-
-	BCD_TO_BIN(sec);
-	BCD_TO_BIN(min);
-	BCD_TO_BIN(hour);
-	BCD_TO_BIN(day);
-	BCD_TO_BIN(mon);
-	BCD_TO_BIN(year);
-
-	if (century) {
-		BCD_TO_BIN(century);
-		year += century * 100;
-		printk(KERN_INFO "Extended CMOS year: %d\n", century * 100);
-	} else {
-		/*
-		 * x86-64 systems only exists since 2002.
-		 * This will work up to Dec 31, 2100
-		 */
-		year += 2000;
-	}
-
-	return mktime(year, mon, day, hour, min, sec);
-}
-
 /* calibrate_cpu is used on systems with fixed rate TSCs to determine
  * processor frequency */
 #define TICK_COUNT 100000000