Messages in this thread Patch in this message | | | From | Matt Mackall <> | Subject | [PATCH 4/14] RTC: Remove RTC UIP synchronization on PPC CHRP (arch/ppc) | Date | Fri, 17 Mar 2006 17:30:35 -0600 |
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Remove RTC UIP synchronization on PPC CHRP (arch/ppc)
Signed-off-by: Matt Mackall <mpm@selenic.com>
Index: rtc/arch/ppc/platforms/chrp_time.c =================================================================== --- rtc.orig/arch/ppc/platforms/chrp_time.c 2005-10-27 19:02:08.000000000 -0500 +++ rtc/arch/ppc/platforms/chrp_time.c 2006-03-12 13:00:51.000000000 -0600 @@ -121,33 +121,15 @@ int __chrp chrp_set_rtc_time(unsigned lo unsigned long __chrp 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) { - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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