hrtime.h

来自「Linux Kernel 2.6.9 for OMAP1710」· C头文件 代码 · 共 53 行

/* 
 * linux/include/asm-arm/arch-omap2/hrtime.h
 * 
 * HRT hooks for the TI OMAP2
 *
 * Copyright (C) 2004 Texas Instruments, Inc. 
 * 
 * This package is free software; you can redistribute it and/or modify 
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation. 
 * 
 * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 
 */

#ifndef __ASM_ARM_ARCH_OMAP2_HRTIME_H
#define __ASM_ARM_ARCH_OMAP2_HRTIME_H

#include <linux/timex.h>

int schedule_hr_timer_int(unsigned, int);
int get_arch_cycles(unsigned);
extern int hrtimer_use;

#define hr_time_resolution      1000
#define arch_cycles_per_jiffy   (CLOCK_TICK_RATE / HZ)
#define schedule_jiffies_int(x) (get_arch_cycles(x) >= arch_cycles_per_jiffy)

/* These values has to be chosen to aviod both underflow and overflow during
 * computation
 * this can be acheived by inputting all the possible values and checking
 * the result after computation
 * these values were directly picked from celinux sources for 1510
 */

#define SC_ARCH2NSEC            23
#define SC_NSEC2ARCH            32

#define scaled_nsec_per_arch_cycle      \
        (SC_n(SC_ARCH2NSEC, NSEC_PER_SEC) / CLOCK_TICK_RATE)

#define scaled_arch_cycles_per_nsec     \
        (SC_n(SC_NSEC2ARCH, CLOCK_TICK_RATE) / NSEC_PER_SEC)

#define arch_cycle_to_nsec(cycles)      \
        mpy_sc_n(SC_ARCH2NSEC, (cycles), scaled_nsec_per_arch_cycle)

#define nsec_to_arch_cycle(nsec)        \
        mpy_sc_n(SC_NSEC2ARCH, (nsec), scaled_arch_cycles_per_nsec)

#endif				/* __ASM_ARM_ARCH_OMAP2_HRTIME_H */