alpha: convert to use arch_gettimeoffset()
john stultz [Tue, 22 Sep 2009 00:04:00 +0000 (17:04 -0700)]
Converts alpha to use GENERIC_TIME via the arch_getoffset()
infrastructure, reducing the amount of arch specific code we need to
maintain.

I suspect the alpha arch could even be further improved to provide and
rpcc() based clocksource, but not having the hardware, I don't feel
comfortable attempting the more complicated conversion (but I'd be glad to
help if anyone else is interested).

[akpm@linux-foundation.org: fix build]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/alpha/Kconfig
arch/alpha/kernel/time.c

index 9fb8aae..4434481 100644 (file)
@@ -45,6 +45,14 @@ config GENERIC_CALIBRATE_DELAY
        bool
        default y
 
+config GENERIC_TIME
+       bool
+       default y
+
+config ARCH_USES_GETTIMEOFFSET
+       bool
+       default y
+
 config ZONE_DMA
        bool
        default y
index b04e2cb..5d08266 100644 (file)
@@ -408,28 +408,17 @@ time_init(void)
  * part.  So we can't do the "find absolute time in terms of cycles" thing
  * that the other ports do.
  */
-void
-do_gettimeofday(struct timeval *tv)
+u32 arch_gettimeoffset(void)
 {
-       unsigned long flags;
-       unsigned long sec, usec, seq;
-       unsigned long delta_cycles, delta_usec, partial_tick;
-
-       do {
-               seq = read_seqbegin_irqsave(&xtime_lock, flags);
-
-               delta_cycles = rpcc() - state.last_time;
-               sec = xtime.tv_sec;
-               usec = (xtime.tv_nsec / 1000);
-               partial_tick = state.partial_tick;
-
-       } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
-
 #ifdef CONFIG_SMP
        /* Until and unless we figure out how to get cpu cycle counters
           in sync and keep them there, we can't use the rpcc tricks.  */
-       delta_usec = 0;
+       return 0;
 #else
+       unsigned long delta_cycles, delta_usec, partial_tick;
+
+       delta_cycles = rpcc() - state.last_time;
+       partial_tick = state.partial_tick;
        /*
         * usec = cycles * ticks_per_cycle * 2**48 * 1e6 / (2**48 * ticks)
         *      = cycles * (s_t_p_c) * 1e6 / (2**48 * ticks)
@@ -446,64 +435,10 @@ do_gettimeofday(struct timeval *tv)
        delta_usec = (delta_cycles * state.scaled_ticks_per_cycle 
                      + partial_tick) * 15625;
        delta_usec = ((delta_usec / ((1UL << (FIX_SHIFT-6-1)) * HZ)) + 1) / 2;
+       return delta_usec * 1000;
 #endif
-
-       usec += delta_usec;
-       if (usec >= 1000000) {
-               sec += 1;
-               usec -= 1000000;
-       }
-
-       tv->tv_sec = sec;
-       tv->tv_usec = usec;
 }
 
-EXPORT_SYMBOL(do_gettimeofday);
-
-int
-do_settimeofday(struct timespec *tv)
-{
-       time_t wtm_sec, sec = tv->tv_sec;
-       long wtm_nsec, nsec = tv->tv_nsec;
-       unsigned long delta_nsec;
-
-       if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
-               return -EINVAL;
-
-       write_seqlock_irq(&xtime_lock);
-
-       /* The offset that is added into time in do_gettimeofday above
-          must be subtracted out here to keep a coherent view of the
-          time.  Without this, a full-tick error is possible.  */
-
-#ifdef CONFIG_SMP
-       delta_nsec = 0;
-#else
-       delta_nsec = rpcc() - state.last_time;
-       delta_nsec = (delta_nsec * state.scaled_ticks_per_cycle 
-                     + state.partial_tick) * 15625;
-       delta_nsec = ((delta_nsec / ((1UL << (FIX_SHIFT-6-1)) * HZ)) + 1) / 2;
-       delta_nsec *= 1000;
-#endif
-
-       nsec -= delta_nsec;
-
-       wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
-       wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
-
-       set_normalized_timespec(&xtime, sec, nsec);
-       set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
-
-       ntp_clear();
-
-       write_sequnlock_irq(&xtime_lock);
-       clock_was_set();
-       return 0;
-}
-
-EXPORT_SYMBOL(do_settimeofday);
-
-
 /*
  * In order to set the CMOS clock precisely, set_rtc_mmss has to be
  * called 500 ms after the second nowtime has started, because when