From: Greg Ungerer <gerg@snapgear.com>
To: torvalds@linux-foundation.org
Cc: gerg@uclinux.org, linux-kernel@vger.kernel.org
Subject: [PATCH] m68knommu: fix ColdFire timer off by 1
Date: Fri, 1 Jun 2007 21:07:31 +1000 [thread overview]
Message-ID: <200706011107.l51B7VQl023531@goober> (raw)
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.
Signed-off-by: Philippe De Muyter <phdm@macqel.be>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
---
diff -Naur linux-2.6.21/arch/m68knommu/platform/5307/timers.c linux-2.6.21-uc0/arch/m68knommu/platform/5307/timers.c
--- linux-2.6.21/arch/m68knommu/platform/5307/timers.c 2007-05-01 17:12:41.000000000 +1000
+++ linux-2.6.21-uc0/arch/m68knommu/platform/5307/timers.c 2007-05-01 17:16:11.000000000 +1000
@@ -62,10 +62,13 @@
/***************************************************************************/
+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));
@@ -81,11 +84,10 @@
unsigned long coldfire_timer_offset(void)
{
- unsigned long trr, tcn, offset;
+ unsigned long 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))
reply other threads:[~2007-06-01 11:08 UTC|newest]
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