[PATCH] RTC: Remove RTC UIP synchronization on MIPS-based DEC

Move real_year inside the read loop and move the spinlock up as well

Signed-off-by: Matt Mackall <mpm@selenic.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/mips/dec/time.c b/arch/mips/dec/time.c
index f17d3378e9a6796aaf76df4415c13bc58a9ce0d7..74cb055d4bf64d859923a6aeb33fa23bded02f84 100644 (file)
--- a/arch/mips/dec/time.c
+++ b/arch/mips/dec/time.c
@@ -36,41 +36,13 @@
 #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);
@@ -78,7 +50,16 @@ 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);
@@ -87,13 +68,7 @@ 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);