x86: enable ACPI extended century handling for 32bit

[linux-2.6-omap-h63xx.git] / arch / x86 / kernel / rtc.c

diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c
index 45bf54d9f4c52f9be2cd5552c3ff13eb5640591c..91492190ac7298c1a83a5f59b1a30dfcf43624d3 100644 (file)
--- a/arch/x86/kernel/rtc.c
+++ b/arch/x86/kernel/rtc.c
@@ -1,10 +1,28 @@
 /*
  * RTC related functions
  */
+#include <linux/acpi.h>
 #include <linux/bcd.h>
 #include <linux/mc146818rtc.h>
 
 #include <asm/time.h>
+#include <asm/vsyscall.h>
+
+#ifdef CONFIG_X86_32
+/*
+ * 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);
+#endif
+
+/* For two digit years assume time is always after that */
+#define CMOS_YEARS_OFFS 2000
+
+DEFINE_SPINLOCK(rtc_lock);
+EXPORT_SYMBOL(rtc_lock);
 
 /*
  * In order to set the CMOS clock precisely, set_rtc_mmss has to be
@@ -22,10 +40,12 @@ 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 +60,9 @@ 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 +94,34 @@ 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 status, 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);
+
+#ifdef CONFIG_ACPI
+       if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
+           acpi_gbl_FADT.century)
+               century = CMOS_READ(acpi_gbl_FADT.century);
+#endif
+
+       status = CMOS_READ(RTC_CONTROL);
+       WARN_ON_ONCE(RTC_ALWAYS_BCD && (status & RTC_DM_BINARY));
+
+       if (RTC_ALWAYS_BCD || !(status & RTC_DM_BINARY)) {
                BCD_TO_BIN(sec);
                BCD_TO_BIN(min);
                BCD_TO_BIN(hour);
@@ -93,24 +130,16 @@ 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;
 
        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 +167,6 @@ 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 +177,7 @@ 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();
@@ -164,3 +190,10 @@ int update_persistent_clock(struct timespec now)
 {
        return set_rtc_mmss(now.tv_sec);
 }
+
+unsigned long long native_read_tsc(void)
+{
+       return __native_read_tsc();
+}
+EXPORT_SYMBOL(native_read_tsc);
+