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Commit 6f0d7bd6 authored by Matt Mackall's avatar Matt Mackall Committed by Linus Torvalds
Browse files

[PATCH] RTC: Remove RTC UIP synchronization on PPC Maple 



Signed-off-by: default avatarMatt 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: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 4dc12ec7

arch/powerpc/platforms/maple/time.c

+2 −22
Original line number Original line Diff line number Diff line
@@ -60,34 +60,14 @@ static void maple_clock_write(unsigned long val, int addr) 




void maple_get_rtc_time(struct rtc_time *tm)

void maple_get_rtc_time(struct rtc_time *tm)

{

{

	int uip, i;

	do {



	/* 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);

		tm->tm_sec = maple_clock_read(RTC_SECONDS);

		tm->tm_sec = maple_clock_read(RTC_SECONDS);

		tm->tm_min = maple_clock_read(RTC_MINUTES);

		tm->tm_min = maple_clock_read(RTC_MINUTES);

		tm->tm_hour = maple_clock_read(RTC_HOURS);

		tm->tm_hour = maple_clock_read(RTC_HOURS);

		tm->tm_mday = maple_clock_read(RTC_DAY_OF_MONTH);

		tm->tm_mday = maple_clock_read(RTC_DAY_OF_MONTH);

		tm->tm_mon = maple_clock_read(RTC_MONTH);

		tm->tm_mon = maple_clock_read(RTC_MONTH);

		tm->tm_year = maple_clock_read(RTC_YEAR);

		tm->tm_year = maple_clock_read(RTC_YEAR);

		uip |= maple_clock_read(RTC_FREQ_SELECT);

	} while (tm->tm_sec != maple_clock_read(RTC_SECONDS));

		if ((uip & RTC_UIP)==0)

			break;

	}





	if (!(maple_clock_read(RTC_CONTROL) & RTC_DM_BINARY)

	if (!(maple_clock_read(RTC_CONTROL) & RTC_DM_BINARY)

	    || RTC_ALWAYS_BCD) {

	    || RTC_ALWAYS_BCD) {