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author | 2006-03-28 01:56:06 -0800 | |
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committer | 2006-03-28 09:16:01 -0800 | |
commit | ddcabb4fc7f2f4a70f35aa72827888a4c549d355 (patch) | |
tree | a730f9c35f76d88ec5f586dc415e427f618589a5 | |
parent | [PATCH] RTC: Remove RTC UIP synchronization on MIPS MC146818 (diff) | |
download | linux-ddcabb4fc7f2f4a70f35aa72827888a4c549d355.tar.gz linux-ddcabb4fc7f2f4a70f35aa72827888a4c549d355.tar.bz2 linux-ddcabb4fc7f2f4a70f35aa72827888a4c549d355.zip |
[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>
-rw-r--r-- | arch/mips/dec/time.c | 47 |
1 files changed, 11 insertions, 36 deletions
diff --git a/arch/mips/dec/time.c b/arch/mips/dec/time.c index f17d3378e9a6..74cb055d4bf6 100644 --- 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); |