From 6f0d7bd6a14dcf5b258cfd809143c50e4897902b Mon Sep 17 00:00:00 2001 From: Matt Mackall Date: Tue, 28 Mar 2006 01:56:04 -0800 Subject: [PATCH] [PATCH] RTC: Remove RTC UIP synchronization on PPC Maple Signed-off-by: Matt Mackall Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Alessandro Zummo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/powerpc/platforms/maple/time.c | 24 ++---------------------- 1 file changed, 2 insertions(+), 22 deletions(-) diff --git a/arch/powerpc/platforms/maple/time.c b/arch/powerpc/platforms/maple/time.c index 5e6981d..b9a2b3d 100644 --- a/arch/powerpc/platforms/maple/time.c +++ b/arch/powerpc/platforms/maple/time.c @@ -60,34 +60,14 @@ static void maple_clock_write(unsigned long val, int addr) void maple_get_rtc_time(struct rtc_time *tm) { - int uip, i; - - /* The Linux interpretation of the CMOS 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. - */ - - /* Since the UIP flag is set for about 2.2 ms and the clock - * is typically written with a precision of 1 jiffy, trying - * to obtain a precision better than a few milliseconds is - * an illusion. Only consistency is interesting, this also - * allows to use the routine for /dev/rtc without a potential - * 1 second kernel busy loop triggered by any reader of /dev/rtc. - */ - - for (i = 0; i<1000000; i++) { - uip = maple_clock_read(RTC_FREQ_SELECT); + do { tm->tm_sec = maple_clock_read(RTC_SECONDS); tm->tm_min = maple_clock_read(RTC_MINUTES); tm->tm_hour = maple_clock_read(RTC_HOURS); tm->tm_mday = maple_clock_read(RTC_DAY_OF_MONTH); tm->tm_mon = maple_clock_read(RTC_MONTH); tm->tm_year = maple_clock_read(RTC_YEAR); - uip |= maple_clock_read(RTC_FREQ_SELECT); - if ((uip & RTC_UIP)==0) - break; - } + } while (tm->tm_sec != maple_clock_read(RTC_SECONDS)); if (!(maple_clock_read(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { -- 2.7.4