[PATCH] RTC: Remove RTC UIP synchronization on CHRP (arch/powerpc)
Signed-off-by: Matt Mackall <mpm@selenic.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/powerpc/platforms/chrp/time.c b/arch/powerpc/platforms/chrp/time.c
index 12c6f68..7d78890 100644
--- a/arch/powerpc/platforms/chrp/time.c
+++ b/arch/powerpc/platforms/chrp/time.c
@@ -120,33 +120,15 @@
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);
