diff options
| author | Sebastian Siewior <bigeasy@linutronix.de> | 2008-04-28 11:43:03 +0200 |
|---|---|---|
| committer | Greg Ungerer <gerg@uclinux.org> | 2008-07-23 15:11:28 +1000 |
| commit | 5bed10a5ee272fbf18ce0ce764245bbb8f28e2e6 (patch) | |
| tree | e358b64949a0b709982c31b87381f40821af9873 /arch | |
| parent | 95469bd64a7a9ab405b566deb8c81d4aaf67ed9e (diff) | |
m68knommu: add sched_clock() for the DMA timer
with this printk() and other sched_clock() user use the more precise
timestamps. The highly optimized math is from arch/x86/kernel/tsc_32.c.
Signed-off-by: Sebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/m68knommu/platform/coldfire/dma_timer.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/m68knommu/platform/coldfire/dma_timer.c b/arch/m68knommu/platform/coldfire/dma_timer.c index b623c993219..772578b1084 100644 --- a/arch/m68knommu/platform/coldfire/dma_timer.c +++ b/arch/m68knommu/platform/coldfire/dma_timer.c @@ -66,3 +66,19 @@ static int __init init_cf_dt_clocksource(void) } arch_initcall(init_cf_dt_clocksource); + +#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */ +#define CYC2NS_SCALE ((1000000 << CYC2NS_SCALE_FACTOR) / (DMA_FREQ / 1000)) + +static unsigned long long cycles2ns(unsigned long cycl) +{ + return (unsigned long long) ((unsigned long long)cycl * + CYC2NS_SCALE) >> CYC2NS_SCALE_FACTOR; +} + +unsigned long long sched_clock(void) +{ + unsigned long cycl = __raw_readl(DTCN0); + + return cycles2ns(cycl); +} |