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authorThomas Gleixner <tglx@linutronix.de>2007-07-21 04:37:37 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-21 17:49:15 -0700
commit82644459c592a28a3eab682f9b88d81019ddfe8b (patch)
tree738e4edaf54658912e78a8bcdadc3e2165ecb77a /kernel
parent99bc2fcb283852931fb6bbef40f3df8316b59000 (diff)
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NTP: move the cmos update code into ntp.c
i386 and sparc64 have the identical code to update the cmos clock. Move it into kernel/time/ntp.c as there are other architectures coming along with the same requirements. [akpm@linux-foundation.org: build fixes] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: David Miller <davem@davemloft.net> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/time/ntp.c59
1 files changed, 56 insertions, 3 deletions
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index b5e352597cb..cd91237dbfe 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -10,6 +10,7 @@
#include <linux/mm.h>
#include <linux/time.h>
+#include <linux/timer.h>
#include <linux/timex.h>
#include <linux/jiffies.h>
#include <linux/hrtimer.h>
@@ -175,12 +176,64 @@ u64 current_tick_length(void)
return tick_length;
}
+#ifdef CONFIG_GENERIC_CMOS_UPDATE
-void __attribute__ ((weak)) notify_arch_cmos_timer(void)
+/* Disable the cmos update - used by virtualization and embedded */
+int no_sync_cmos_clock __read_mostly;
+
+static void sync_cmos_clock(unsigned long dummy);
+
+static DEFINE_TIMER(sync_cmos_timer, sync_cmos_clock, 0, 0);
+
+static void sync_cmos_clock(unsigned long dummy)
+{
+ struct timespec now, next;
+ int fail = 1;
+
+ /*
+ * If we have an externally synchronized Linux clock, then update
+ * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
+ * called as close as possible to 500 ms before the new second starts.
+ * This code is run on a timer. If the clock is set, that timer
+ * may not expire at the correct time. Thus, we adjust...
+ */
+ if (!ntp_synced())
+ /*
+ * Not synced, exit, do not restart a timer (if one is
+ * running, let it run out).
+ */
+ return;
+
+ getnstimeofday(&now);
+ if (abs(xtime.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
+ fail = update_persistent_clock(now);
+
+ next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec;
+ if (next.tv_nsec <= 0)
+ next.tv_nsec += NSEC_PER_SEC;
+
+ if (!fail)
+ next.tv_sec = 659;
+ else
+ next.tv_sec = 0;
+
+ if (next.tv_nsec >= NSEC_PER_SEC) {
+ next.tv_sec++;
+ next.tv_nsec -= NSEC_PER_SEC;
+ }
+ mod_timer(&sync_cmos_timer, jiffies + timespec_to_jiffies(&next));
+}
+
+static void notify_cmos_timer(void)
{
- return;
+ if (no_sync_cmos_clock)
+ mod_timer(&sync_cmos_timer, jiffies + 1);
}
+#else
+static inline void notify_cmos_timer(void) { }
+#endif
+
/* adjtimex mainly allows reading (and writing, if superuser) of
* kernel time-keeping variables. used by xntpd.
*/
@@ -345,6 +398,6 @@ leave: if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0)
txc->stbcnt = 0;
write_sequnlock_irq(&xtime_lock);
do_gettimeofday(&txc->time);
- notify_arch_cmos_timer();
+ notify_cmos_timer();
return(result);
}