[uClinux-dev] [PATCH] Fix coldfire timer initialisation

[Philippe De Muyter]

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.  Fix that
Actual debugging work has been made on a 5272.  I hope it's the same for
the other coldfire's.

Signed-off-by: Philippe De Muyter <phdm at macqel.be>

diff -r 9ed3c4dc013f arch/m68knommu/platform/5307/timers.c
--- a/arch/m68knommu/platform/5307/timers.c	Wed Feb 21 13:02:17 2007 -0800
+++ b/arch/m68knommu/platform/5307/timers.c	Mon Mar 19 16:48:00 2007 +0100
@@ -62,10 +62,13 @@ void coldfire_tick(void)
 
 /***************************************************************************/
 
+static int ticks_per_intr;
+
 void coldfire_timer_init(irq_handler_t handler)
 {
 	__raw_writew(MCFTIMER_TMR_DISABLE, TA(MCFTIMER_TMR));
-	__raw_writetrr(((MCF_BUSCLK / 16) / HZ), TA(MCFTIMER_TRR));
+	ticks_per_intr = (MCF_BUSCLK / 16) / HZ;
+	__raw_writetrr(ticks_per_intr - 1, TA(MCFTIMER_TRR));
 	__raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
 		MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, TA(MCFTIMER_TMR));
 
@@ -84,8 +87,7 @@ unsigned long coldfire_timer_offset(void
 	unsigned long trr, tcn, offset;
 
 	tcn = __raw_readw(TA(MCFTIMER_TCN));
-	trr = __raw_readtrr(TA(MCFTIMER_TRR));
-	offset = (tcn * (1000000 / HZ)) / trr;
+	offset = ((tcn + 1) * (1000000 / HZ)) / ticks_per_intr;
 
 	/* Check if we just wrapped the counters and maybe missed a tick */
 	if ((offset < (1000000 / HZ / 2)) && mcf_timerirqpending(1))
-- 
Philippe De Muyter  phdm at macqel dot be  Tel +32 27029044
Macq Electronique SA  rue de l'Aeronef 2  B-1140 Bruxelles  Fax +32 27029077