diff options
| author | Philippe De Muyter <phdm@macqel.be> | 2008-06-12 15:21:36 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-06-12 18:05:40 -0700 |
| commit | 6c38d8578545482fe45d6e6ea37be02a2e1bb289 (patch) | |
| tree | 05f291e2fc1e9cf89398aed63b843bfe6c766789 /arch | |
| parent | 67dddaad5d8b8c5ee5b96a7e2f6cb0faad703865 (diff) | |
m68knommu: init coldfire timer TRR with n - 1, not n
The coldfire timer must be initialised to n - 1 if we want it to count n
cycles between each tick interrupt. This was already fixed, but has been
lost with the conversion to GENERIC_TIMER.
Signed-off-by: Philippe De Muyter <phdm@macqel.be>
Acked-by: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/m68knommu/platform/coldfire/timers.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/m68knommu/platform/coldfire/timers.c b/arch/m68knommu/platform/coldfire/timers.c index ba5a9f32ebd..454f2549349 100644 --- a/arch/m68knommu/platform/coldfire/timers.c +++ b/arch/m68knommu/platform/coldfire/timers.c @@ -111,7 +111,13 @@ void hw_timer_init(void) __raw_writew(MCFTIMER_TMR_DISABLE, TA(MCFTIMER_TMR)); mcftmr_cycles_per_jiffy = FREQ / HZ; - __raw_writetrr(mcftmr_cycles_per_jiffy, TA(MCFTIMER_TRR)); + /* + * The coldfire timer runs from 0 to TRR included, then 0 + * again and so on. It counts thus actually TRR + 1 steps + * for 1 tick, not TRR. So if you want n cycles, + * initialize TRR with n - 1. + */ + __raw_writetrr(mcftmr_cycles_per_jiffy - 1, TA(MCFTIMER_TRR)); __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 | MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, TA(MCFTIMER_TMR)); |