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Subject[PATCH 6/14] RTC: Remove RTC UIP synchronization on PPC Maple
Date
Remove RTC UIP synchronization on PPC Maple

Signed-off-by: Matt Mackall <mpm@selenic.com>

Index: rtc/arch/powerpc/platforms/maple/time.c
===================================================================
--- rtc.orig/arch/powerpc/platforms/maple/time.c 2006-03-16 16:48:37.000000000 -0600
+++ rtc/arch/powerpc/platforms/maple/time.c 2006-03-16 19:00:12.000000000 -0600
@@ -62,34 +62,14 @@ static void maple_clock_write(unsigned l

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) {
-
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