linux 2.6.16.38 w/ vs2.0.3-rc1

[linux-2.6.git] / arch / mips / dec / time.c

diff --git a/arch/mips/dec/time.c b/arch/mips/dec/time.c
index 5729474..1748223 100644 (file)
--- a/arch/mips/dec/time.c
+++ b/arch/mips/dec/time.c
@@ -36,13 +36,41 @@
 #include <asm/dec/ioasic_addrs.h>
 #include <asm/dec/machtype.h>
 
+
+/*
+ * Returns true if a clock update is in progress
+ */
+static inline unsigned char dec_rtc_is_updating(void)
+{
+       unsigned char uip;
+       unsigned long flags;
+
+       spin_lock_irqsave(&rtc_lock, flags);
+       uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
+       spin_unlock_irqrestore(&rtc_lock, flags);
+       return uip;
+}
+
 static unsigned long dec_rtc_get_time(void)
 {
        unsigned int year, mon, day, hour, min, sec, real_year;
+       int i;
        unsigned long flags;
 
+       /* The Linux interpretation of the DS1287 clock register contents:
+        * When the Update-In-Progress (UIP) flag goes from 1 to 0, the
+        * RTC registers show the second which has precisely just started.
+        * Let's hope other operating systems interpret the RTC the same way.
+        */
+       /* read RTC exactly on falling edge of update flag */
+       for (i = 0; i < 1000000; i++)   /* may take up to 1 second... */
+               if (dec_rtc_is_updating())
+                       break;
+       for (i = 0; i < 1000000; i++)   /* must try at least 2.228 ms */
+               if (!dec_rtc_is_updating())
+                       break;
        spin_lock_irqsave(&rtc_lock, flags);
-
+       /* Isn't this overkill?  UIP above should guarantee consistency */
        do {
                sec = CMOS_READ(RTC_SECONDS);
                min = CMOS_READ(RTC_MINUTES);
@@ -50,16 +78,7 @@ static unsigned long dec_rtc_get_time(void)
                day = CMOS_READ(RTC_DAY_OF_MONTH);
                mon = CMOS_READ(RTC_MONTH);
                year = CMOS_READ(RTC_YEAR);
-               /*
-                * The PROM will reset the year to either '72 or '73.
-                * Therefore we store the real year separately, in one
-                * of unused BBU RAM locations.
-                */
-               real_year = CMOS_READ(RTC_DEC_YEAR);
        } while (sec != CMOS_READ(RTC_SECONDS));
-
-       spin_unlock_irqrestore(&rtc_lock, flags);
-
        if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
                sec = BCD2BIN(sec);
                min = BCD2BIN(min);
@@ -68,7 +87,13 @@ static unsigned long dec_rtc_get_time(void)
                mon = BCD2BIN(mon);
                year = BCD2BIN(year);
        }
-
+       /*
+        * The PROM will reset the year to either '72 or '73.
+        * Therefore we store the real year separately, in one
+        * of unused BBU RAM locations.
+        */
+       real_year = CMOS_READ(RTC_DEC_YEAR);
+       spin_unlock_irqrestore(&rtc_lock, flags);
        year += real_year - 72 + 2000;
 
        return mktime(year, mon, day, hour, min, sec);
@@ -168,8 +193,8 @@ static void dec_ioasic_hpt_init(unsigned int count)
 
 void __init dec_time_init(void)
 {
-       rtc_mips_get_time = dec_rtc_get_time;
-       rtc_mips_set_mmss = dec_rtc_set_mmss;
+       rtc_get_time = dec_rtc_get_time;
+       rtc_set_mmss = dec_rtc_set_mmss;
 
        mips_timer_state = dec_timer_state;
        mips_timer_ack = dec_timer_ack;
@@ -181,12 +206,12 @@ void __init dec_time_init(void)
        }
 
        /* Set up the rate of periodic DS1287 interrupts.  */
-       CMOS_WRITE(RTC_REF_CLCK_32KHZ | (16 - __ffs(HZ)), RTC_REG_A);
+       CMOS_WRITE(RTC_REF_CLCK_32KHZ | (16 - LOG_2_HZ), RTC_REG_A);
 }
 
 EXPORT_SYMBOL(do_settimeofday);
 
-void __init plat_timer_setup(struct irqaction *irq)
+void __init dec_timer_setup(struct irqaction *irq)
 {
        setup_irq(dec_interrupt[DEC_IRQ_RTC], irq);