diff options
| author | Atsushi Nemoto <anemo@mba.ocn.ne.jp> | 2005-11-03 01:01:15 +0900 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2005-11-07 18:05:38 +0000 |
| commit | 53c2df2f4ebbc1d8231ca7cc13ac5381230888b1 (patch) | |
| tree | a7446ec56dd877d77ef7318b4bcdc3d38555ff0a /include | |
| parent | e329331aedeca0f2a7e15bd26a829ee1619c05e0 (diff) | |
| download | linux-53c2df2f4ebbc1d8231ca7cc13ac5381230888b1.tar.gz | |
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 'include')
| -rw-r--r-- | include/asm-mips/mc146818-time.h | 24 | ||||
| -rw-r--r-- | include/asm-mips/time.h | 3 |
2 files changed, 25 insertions, 2 deletions
diff --git a/include/asm-mips/mc146818-time.h b/include/asm-mips/mc146818-time.h index a2c2d2c24303..47214861093b 100644 --- a/include/asm-mips/mc146818-time.h +++ b/include/asm-mips/mc146818-time.h @@ -33,7 +33,9 @@ static inline int mc146818_set_rtc_mmss(unsigned long nowtime) int real_seconds, real_minutes, cmos_minutes; unsigned char save_control, save_freq_select; int retval = 0; + unsigned long flags; + spin_lock_irqsave(&rtc_lock, flags); save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */ CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL); @@ -79,14 +81,30 @@ static inline int mc146818_set_rtc_mmss(unsigned long nowtime) */ CMOS_WRITE(save_control, RTC_CONTROL); CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT); + spin_unlock_irqrestore(&rtc_lock, flags); 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: @@ -97,12 +115,13 @@ static inline unsigned long mc146818_get_cmos_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 (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 (!rtc_is_updating()) break; + spin_lock_irqsave(&rtc_lock, flags); do { /* Isn't this overkill ? UIP above should guarantee consistency */ sec = CMOS_READ(RTC_SECONDS); min = CMOS_READ(RTC_MINUTES); @@ -120,6 +139,7 @@ static inline unsigned long mc146818_get_cmos_time(void) BCD_TO_BIN(mon); BCD_TO_BIN(year); } + spin_unlock_irqrestore(&rtc_lock, flags); year = mc146818_decode_year(year); return mktime(year, mon, day, hour, min, sec); diff --git a/include/asm-mips/time.h b/include/asm-mips/time.h index e22a20665871..9cc3564cc2c9 100644 --- a/include/asm-mips/time.h +++ b/include/asm-mips/time.h @@ -20,6 +20,9 @@ #include <linux/linkage.h> #include <linux/ptrace.h> #include <linux/rtc.h> +#include <linux/spinlock.h> + +extern spinlock_t rtc_lock; /* * RTC ops. By default, they point to no-RTC functions. |