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Commit 5bed10a5 authored by Sebastian Siewior's avatar Sebastian Siewior Committed by Greg Ungerer
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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: default avatarSebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarGreg Ungerer <gerg@uclinux.org>
parent 95469bd6

arch/m68knommu/platform/coldfire/dma_timer.c

+16 −0
Original line number Diff line number Diff line
@@ -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);

}