CRIS: GENERIC_TIME fixes

GENERIC_TIME was not functional for CRIS, giving random backward
time jumps.

For CRISv32 implement a new clocksource using the free running counter
and ditch the arch_gettimeoffset.

The random time jumps still existed, but turned out to be the write_seqlock
which was missing around our do_timer() call.

So switch over to GENERIC_TIME using the clocksource for CRISv32.

CRISv10 doesn't have the free running counter needed for the
clocksource trick, but we can still use GENERIC_TIME with
arch_gettimeoffset.

Unfortunately, there were problems in using the prescaler register
to timer0 for the gettimeoffset calculation, so it is now ignored,
making our resolution worse by the tune of 40usec (0.4%) worst case.

At the same time, clean up some formatting and use NSEC_PER_SEC
instead of 1000000000.

Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/arch/cris/kernel/time.c b/arch/cris/kernel/time.c
index c72730d20ef6..b5096430ce1c 100644
--- a/arch/cris/kernel/time.c
+++ b/arch/cris/kernel/time.c
@@ -39,13 +39,16 @@ int have_rtc;  /* used to remember if we have an RTC or not */;
 extern unsigned long loops_per_jiffy; /* init/main.c */
 unsigned long loops_per_usec;
 
+
+#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
 extern unsigned long do_slow_gettimeoffset(void);
 static unsigned long (*do_gettimeoffset)(void) = do_slow_gettimeoffset;
 
 u32 arch_gettimeoffset(void)
 {
-        return do_gettimeoffset() * 1000;
+       return do_gettimeoffset() * 1000;
 }
+#endif
 
 /*
  * BUG: This routine does not handle hour overflow properly; it just
@@ -151,7 +154,7 @@ cris_do_profile(struct pt_regs* regs)
 
 unsigned long long sched_clock(void)
 {
-        return (unsigned long long)jiffies * (1000000000 / HZ) +
+        return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ) +
                 get_ns_in_jiffie();
 }