[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>
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1 changed files with 11 additions and 36 deletions
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@ -36,41 +36,13 @@
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#include <asm/dec/ioasic_addrs.h>
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#include <asm/dec/ioasic_addrs.h>
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#include <asm/dec/machtype.h>
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#include <asm/dec/machtype.h>
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/*
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* Returns true if a clock update is in progress
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*/
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static inline unsigned char dec_rtc_is_updating(void)
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{
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unsigned char uip;
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unsigned long flags;
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spin_lock_irqsave(&rtc_lock, flags);
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uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
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spin_unlock_irqrestore(&rtc_lock, flags);
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return uip;
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}
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static unsigned long dec_rtc_get_time(void)
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static unsigned long dec_rtc_get_time(void)
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{
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{
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unsigned int year, mon, day, hour, min, sec, real_year;
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unsigned int year, mon, day, hour, min, sec, real_year;
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int i;
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unsigned long flags;
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unsigned long flags;
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/* The Linux interpretation of the DS1287 clock register contents:
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* When the Update-In-Progress (UIP) flag goes from 1 to 0, the
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* RTC registers show the second which has precisely just started.
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* Let's hope other operating systems interpret the RTC the same way.
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*/
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/* read RTC exactly on falling edge of update flag */
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for (i = 0; i < 1000000; i++) /* may take up to 1 second... */
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if (dec_rtc_is_updating())
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break;
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for (i = 0; i < 1000000; i++) /* must try at least 2.228 ms */
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if (!dec_rtc_is_updating())
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break;
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spin_lock_irqsave(&rtc_lock, flags);
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spin_lock_irqsave(&rtc_lock, flags);
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/* Isn't this overkill? UIP above should guarantee consistency */
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do {
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do {
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sec = CMOS_READ(RTC_SECONDS);
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sec = CMOS_READ(RTC_SECONDS);
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min = CMOS_READ(RTC_MINUTES);
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min = CMOS_READ(RTC_MINUTES);
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@ -78,7 +50,16 @@ static unsigned long dec_rtc_get_time(void)
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day = CMOS_READ(RTC_DAY_OF_MONTH);
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day = CMOS_READ(RTC_DAY_OF_MONTH);
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mon = CMOS_READ(RTC_MONTH);
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mon = CMOS_READ(RTC_MONTH);
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year = CMOS_READ(RTC_YEAR);
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year = CMOS_READ(RTC_YEAR);
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/*
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* The PROM will reset the year to either '72 or '73.
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* Therefore we store the real year separately, in one
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* of unused BBU RAM locations.
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*/
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real_year = CMOS_READ(RTC_DEC_YEAR);
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} while (sec != CMOS_READ(RTC_SECONDS));
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} while (sec != CMOS_READ(RTC_SECONDS));
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spin_unlock_irqrestore(&rtc_lock, flags);
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if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
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if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
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sec = BCD2BIN(sec);
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sec = BCD2BIN(sec);
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min = BCD2BIN(min);
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min = BCD2BIN(min);
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@ -87,13 +68,7 @@ static unsigned long dec_rtc_get_time(void)
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mon = BCD2BIN(mon);
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mon = BCD2BIN(mon);
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year = BCD2BIN(year);
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year = BCD2BIN(year);
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}
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}
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/*
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* The PROM will reset the year to either '72 or '73.
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* Therefore we store the real year separately, in one
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* of unused BBU RAM locations.
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*/
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real_year = CMOS_READ(RTC_DEC_YEAR);
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spin_unlock_irqrestore(&rtc_lock, flags);
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year += real_year - 72 + 2000;
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year += real_year - 72 + 2000;
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return mktime(year, mon, day, hour, min, sec);
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return mktime(year, mon, day, hour, min, sec);
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