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>

3 files changed, 64 insertions, 191 deletions

diff --git a/arch/x86/kernel/Makefile_64 b/arch/x86/kernel/Makefile_64
index 9cb3df27c413..ae95d21ea885 100644
--- a/arch/x86/kernel/Makefile_64
+++ b/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/
diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c
index 45bf54d9f4c5..d040840ff1b6 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 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();
diff --git a/arch/x86/kernel/time_64.c b/arch/x86/kernel/time_64.c
index 0a01504586a5..64cd03ed9bfc 100644
--- a/arch/x86/kernel/time_64.c
+++ b/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