m32r: convert to use arch_gettimeoffset()

Convert m32r to use GENERIC_TIME via the arch_getoffset() infrastructure,
reducing the amount of arch specific code we need to maintain.

I also noted that m32r doesn't seem to be taking the xtime write lock
before calling do_timer()!  That looks like a pretty bad bug to me.  If
folks agree, let me know and I can move the lock grab to the correct spot.

Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 9 insertions, 71 deletions

diff --git a/arch/m32r/Kconfig b/arch/m32r/Kconfig
index cabba332cc48..c41234f1b825 100644
--- a/arch/m32r/Kconfig
+++ b/arch/m32r/Kconfig
@@ -41,6 +41,12 @@ config HZ
         int
         default 100
 
+config GENERIC_TIME
+        def_bool y
+
+config ARCH_USES_GETTIMEOFFSET
+        def_bool y
+
 source "init/Kconfig"
 
 source "kernel/Kconfig.freezer"
diff --git a/arch/m32r/kernel/time.c b/arch/m32r/kernel/time.c
index cada3ba4b990..ba61c4c73202 100644
--- a/arch/m32r/kernel/time.c
+++ b/arch/m32r/kernel/time.c
@@ -48,7 +48,7 @@ extern void smp_local_timer_interrupt(void);
 
 static unsigned long latch;
 
-static unsigned long do_gettimeoffset(void)
+u32 arch_gettimeoffset(void)
 {
         unsigned long  elapsed_time = 0;  /* [us] */
 
@@ -93,79 +93,10 @@ static unsigned long do_gettimeoffset(void)
 #error no chip configuration
 #endif
 
-        return elapsed_time;
+        return elapsed_time * 1000;
 }
 
 /*
- * This version of gettimeofday has near microsecond resolution.
- */
-void do_gettimeofday(struct timeval *tv)
-{
-        unsigned long seq;
-        unsigned long usec, sec;
-        unsigned long max_ntp_tick = tick_usec - tickadj;
-
-        do {
-                seq = read_seqbegin(&xtime_lock);
-
-                usec = do_gettimeoffset();
-
-                /*
-                 * If time_adjust is negative then NTP is slowing the clock
-                 * so make sure not to go into next possible interval.
-                 * Better to lose some accuracy than have time go backwards..
-                 */
-                if (unlikely(time_adjust < 0))
-                        usec = min(usec, max_ntp_tick);
-
-                sec = xtime.tv_sec;
-                usec += (xtime.tv_nsec / 1000);
-        } while (read_seqretry(&xtime_lock, seq));
-
-        while (usec >= 1000000) {
-                usec -= 1000000;
-                sec++;
-        }
-
-        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;
-
-        if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
-                return -EINVAL;
-
-        write_seqlock_irq(&xtime_lock);
-        /*
-         * This is revolting. We need to set "xtime" correctly. However, the
-         * value in this location is the value at the most recent update of
-         * wall time.  Discover what correction gettimeofday() would have
-         * made, and then undo it!
-         */
-        nsec -= do_gettimeoffset() * NSEC_PER_USEC;
-
-        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
  * nowtime is written into the registers of the CMOS clock, it will
@@ -192,6 +123,7 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id)
 #ifndef CONFIG_SMP
         profile_tick(CPU_PROFILING);
 #endif
+        /* XXX FIXME. Uh, the xtime_lock should be held here, no? */
         do_timer(1);
 
 #ifndef CONFIG_SMP