Commit da2468b6 authored by Matt Mackall's avatar Matt Mackall Committed by Linus Torvalds
Browse files

[PATCH] RTC: Remove RTC UIP synchronization on MIPS MC146818


Signed-off-by: default avatarMatt Mackall <mpm@selenic.com>
Cc: Ralf Baechle <ralf@linux-mips.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 4af6ec46
......@@ -86,43 +86,14 @@ static inline int mc146818_set_rtc_mmss(unsigned long nowtime)
return retval;
}
/*
* Returns true if a clock update is in progress
*/
static inline unsigned char rtc_is_updating(void)
{
unsigned char uip;
unsigned long flags;
spin_lock_irqsave(&rtc_lock, flags);
uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
spin_unlock_irqrestore(&rtc_lock, flags);
return uip;
}
static inline unsigned long mc146818_get_cmos_time(void)
{
unsigned int year, mon, day, hour, min, sec;
int i;
unsigned long flags;
/*
* 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 (rtc_is_updating())
break;
for (i = 0 ; i < 1000000 ; i++) /* must try at least 2.228 ms */
if (!rtc_is_updating())
break;
spin_lock_irqsave(&rtc_lock, flags);
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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