timex.h

来自「Linux内核源代码 为压缩文件 是<<Linux内核>&gt」· C头文件 代码 · 共 44 行

/*
 * linux/include/asm-ppc/timex.h
 *
 * ppc architecture timex specifications
 */
#ifdef __KERNEL__
#ifndef _ASMppc_TIMEX_H
#define _ASMppc_TIMEX_H

#include <linux/config.h>

#define CLOCK_TICK_RATE	1193180 /* Underlying HZ */
#define CLOCK_TICK_FACTOR	20	/* Factor of both 1000000 and CLOCK_TICK_RATE */
#define FINETUNE ((((((long)LATCH * HZ - CLOCK_TICK_RATE) << SHIFT_HZ) * \
	(1000000/CLOCK_TICK_FACTOR) / (CLOCK_TICK_RATE/CLOCK_TICK_FACTOR)) \
		<< (SHIFT_SCALE-SHIFT_HZ)) / HZ)

typedef unsigned long cycles_t;

/*
 * For the "cycle" counter we use the timebase lower half.
 * Currently only used on SMP.
 *
 * Since SMP kernels won't run on the PPC601 CPU (which doesn't have
 * the timebase register) anyway, we don't bother checking the CPU version.
 */

extern cycles_t cacheflush_time;

static inline cycles_t get_cycles(void)
{
#ifdef CONFIG_SMP
	cycles_t ret;

	__asm__("mftb %0" : "=r" (ret) : );
	return ret;
#else
	return 0;
#endif
}

#endif
#endif /* __KERNEL__ */