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[PATCH] RTC: Remove RTC UIP synchronization on ARM
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Signed-off-by: Matt Mackall <mpm@selenic.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Matt Mackall authored and Linus Torvalds committed Mar 28, 2006
1 parent 6f0d7bd commit 4af6ec4
Showing 1 changed file with 1 addition and 16 deletions.
17 changes: 1 addition & 16 deletions arch/arm/mach-footbridge/time.c
Original file line number Diff line number Diff line change
Expand Up @@ -34,27 +34,12 @@ static int rtc_base;
static unsigned long __init get_isa_cmos_time(void)
{
unsigned int year, mon, day, hour, min, sec;
int i;

// check to see if the RTC makes sense.....
if ((CMOS_READ(RTC_VALID) & RTC_VRT) == 0)
return mktime(1970, 1, 1, 0, 0, 0);

/* 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.
*/
/* read RTC exactly on falling edge of update flag */
for (i = 0 ; i < 1000000 ; i++) /* may take up to 1 second... */
if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)
break;

for (i = 0 ; i < 1000000 ; i++) /* must try at least 2.228 ms */
if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
break;

do { /* Isn't this overkill ? UIP above should guarantee consistency */
do {
sec = CMOS_READ(RTC_SECONDS);
min = CMOS_READ(RTC_MINUTES);
hour = CMOS_READ(RTC_HOURS);
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