From: Matt Mackall Date: Tue, 28 Mar 2006 09:56:03 +0000 (-0800) Subject: [PATCH] RTC: Remove RTC UIP synchronization on CHRP (arch/powerpc) X-Git-Tag: v2.6.17-rc1~269 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=4dc12ec7e26f287e33065e803bc0aede4c1dbdf3;p=linux-2.6-omap-h63xx.git [PATCH] RTC: Remove RTC UIP synchronization on CHRP (arch/powerpc) Signed-off-by: Matt Mackall Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Alessandro Zummo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/arch/powerpc/platforms/chrp/time.c b/arch/powerpc/platforms/chrp/time.c index 12c6f689b1a..7d788902693 100644 --- a/arch/powerpc/platforms/chrp/time.c +++ b/arch/powerpc/platforms/chrp/time.c @@ -120,33 +120,15 @@ int chrp_set_rtc_time(struct rtc_time *tmarg) void chrp_get_rtc_time(struct rtc_time *tm) { unsigned int year, mon, day, hour, min, sec; - 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 = chrp_cmos_clock_read(RTC_FREQ_SELECT); + do { sec = chrp_cmos_clock_read(RTC_SECONDS); min = chrp_cmos_clock_read(RTC_MINUTES); hour = chrp_cmos_clock_read(RTC_HOURS); day = chrp_cmos_clock_read(RTC_DAY_OF_MONTH); mon = chrp_cmos_clock_read(RTC_MONTH); year = chrp_cmos_clock_read(RTC_YEAR); - uip |= chrp_cmos_clock_read(RTC_FREQ_SELECT); - if ((uip & RTC_UIP)==0) break; - } + } while (sec != chrp_cmos_clock_read(RTC_SECONDS)); if (!(chrp_cmos_clock_read(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { BCD_TO_BIN(sec);