diff options
Diffstat (limited to 'arch/x86_64/kernel/time.c')
| -rw-r--r-- | arch/x86_64/kernel/time.c | 41 |
1 files changed, 12 insertions, 29 deletions
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c index 7f58fa682491..473b514b66e4 100644 --- a/arch/x86_64/kernel/time.c +++ b/arch/x86_64/kernel/time.c @@ -504,42 +504,25 @@ unsigned long long sched_clock(void) static unsigned long get_cmos_time(void) { - unsigned int timeout = 1000000, year, mon, day, hour, min, sec; - unsigned char uip = 0, this = 0; + unsigned int year, mon, day, hour, min, sec; unsigned long flags; unsigned extyear = 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. Waiting for this can take up to 1 - * second, we timeout approximately after 2.4 seconds on a machine with - * standard 8.3 MHz ISA bus. - */ - spin_lock_irqsave(&rtc_lock, flags); - while (timeout && (!uip || this)) { - uip |= this; - this = CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP; - timeout--; - } - - /* - * Here we are safe to assume the registers won't change for a whole - * second, so we just go ahead and read them. - */ - sec = CMOS_READ(RTC_SECONDS); - min = CMOS_READ(RTC_MINUTES); - hour = CMOS_READ(RTC_HOURS); - day = CMOS_READ(RTC_DAY_OF_MONTH); - mon = CMOS_READ(RTC_MONTH); - year = CMOS_READ(RTC_YEAR); - + do { + sec = CMOS_READ(RTC_SECONDS); + min = CMOS_READ(RTC_MINUTES); + hour = CMOS_READ(RTC_HOURS); + day = CMOS_READ(RTC_DAY_OF_MONTH); + mon = CMOS_READ(RTC_MONTH); + year = CMOS_READ(RTC_YEAR); #ifdef CONFIG_ACPI - if (acpi_fadt.revision >= FADT2_REVISION_ID && acpi_fadt.century) - extyear = CMOS_READ(acpi_fadt.century); + if (acpi_fadt.revision >= FADT2_REVISION_ID && + acpi_fadt.century) + extyear = CMOS_READ(acpi_fadt.century); #endif + } while (sec != CMOS_READ(RTC_SECONDS)); spin_unlock_irqrestore(&rtc_lock, flags); |