diff options
| author | Atsushi Nemoto <anemo@mba.ocn.ne.jp> | 2005-11-02 19:01:15 +0300 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2005-11-07 21:05:38 +0300 |
| commit | 53c2df2f4ebbc1d8231ca7cc13ac5381230888b1 (patch) | |
| tree | a7446ec56dd877d77ef7318b4bcdc3d38555ff0a /arch/mips/dec/time.c | |
| parent | e329331aedeca0f2a7e15bd26a829ee1619c05e0 (diff) | |
| download | linux-53c2df2f4ebbc1d8231ca7cc13ac5381230888b1.tar.xz | |
Use rtc_lock to protect RTC operations
Many RTC routines were not protected against each other, so there are
potential races, for example, ntp-update against /dev/rtc. This patch
fixes them using rtc_lock.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/dec/time.c')
| -rw-r--r-- | arch/mips/dec/time.c | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/arch/mips/dec/time.c b/arch/mips/dec/time.c index dc7091caa7aa..174822344131 100644 --- a/arch/mips/dec/time.c +++ b/arch/mips/dec/time.c @@ -37,10 +37,25 @@ #include <asm/dec/machtype.h> +/* + * Returns true if a clock update is in progress + */ +static inline unsigned char dec_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 unsigned long dec_rtc_get_time(void) { unsigned int year, mon, day, hour, min, sec, real_year; int i; + unsigned long flags; /* The Linux interpretation of the DS1287 clock register contents: * When the Update-In-Progress (UIP) flag goes from 1 to 0, the @@ -49,11 +64,12 @@ static unsigned long dec_rtc_get_time(void) */ /* 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) + if (dec_rtc_is_updating()) break; for (i = 0; i < 1000000; i++) /* must try at least 2.228 ms */ - if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)) + if (!dec_rtc_is_updating()) break; + spin_lock_irqsave(&rtc_lock, flags); /* Isn't this overkill? UIP above should guarantee consistency */ do { sec = CMOS_READ(RTC_SECONDS); @@ -77,6 +93,7 @@ static unsigned long dec_rtc_get_time(void) * of unused BBU RAM locations. */ real_year = CMOS_READ(RTC_DEC_YEAR); + spin_unlock_irqrestore(&rtc_lock, flags); year += real_year - 72 + 2000; return mktime(year, mon, day, hour, min, sec); @@ -95,6 +112,8 @@ static int dec_rtc_set_mmss(unsigned long nowtime) int real_seconds, real_minutes, cmos_minutes; unsigned char save_control, save_freq_select; + /* irq are locally disabled here */ + spin_lock(&rtc_lock); /* tell the clock it's being set */ save_control = CMOS_READ(RTC_CONTROL); CMOS_WRITE((save_control | RTC_SET), RTC_CONTROL); @@ -141,6 +160,7 @@ static int dec_rtc_set_mmss(unsigned long nowtime) */ CMOS_WRITE(save_control, RTC_CONTROL); CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT); + spin_unlock(&rtc_lock); return retval; } |