From: Matt Mackall Date: Tue, 28 Mar 2006 09:56:02 +0000 (-0800) Subject: [PATCH] RTC: Remove RTC UIP synchronization on PPC CHRP (arch/ppc) X-Git-Tag: v2.6.17-rc1~270 X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=59937bcdb2bd759d15c792d9798a00da03bf1f48;p=linux-2.6-omap-h63xx.git [PATCH] RTC: Remove RTC UIP synchronization on PPC CHRP (arch/ppc) 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/ppc/platforms/chrp_time.c b/arch/ppc/platforms/chrp_time.c index c8627770af1..e103a36e11a 100644 --- a/arch/ppc/platforms/chrp_time.c +++ b/arch/ppc/platforms/chrp_time.c @@ -119,33 +119,15 @@ int chrp_set_rtc_time(unsigned long nowtime) unsigned long chrp_get_rtc_time(void) { 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) {