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>
diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c
index 45bf54d..d040840 100644
--- a/arch/x86/kernel/rtc.c
+++ b/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 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 @@
*/
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 @@
unsigned long mach_get_cmos_time(void)
{
- unsigned int year, mon, day, hour, min, sec;
+ unsigned int year, mon, day, hour, min, sec, century = 0;
- 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 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();
- if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+ 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 @@
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 @@
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 @@
/* 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();