From ddcabb4fc7f2f4a70f35aa72827888a4c549d355 Mon Sep 17 00:00:00 2001 From: Matt Mackall Date: Tue, 28 Mar 2006 01:56:06 -0800 Subject: [PATCH] [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 Cc: Ralf Baechle Cc: Alessandro Zummo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/mips/dec/time.c | 47 +++++++++++------------------------------------ 1 file changed, 11 insertions(+), 36 deletions(-) diff --git a/arch/mips/dec/time.c b/arch/mips/dec/time.c index f17d337..74cb055 100644 --- a/arch/mips/dec/time.c +++ b/arch/mips/dec/time.c @@ -36,41 +36,13 @@ #include #include - -/* - * 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); -- 1.8.2.3