linux/include/asm-avr32/timex.h
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   1/*
   2 * Copyright (C) 2004-2006 Atmel Corporation
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 */
   8#ifndef __ASM_AVR32_TIMEX_H
   9#define __ASM_AVR32_TIMEX_H
  10
  11/*
  12 * This is the frequency of the timer used for Linux's timer interrupt.
  13 * The value should be defined as accurate as possible or under certain
  14 * circumstances Linux timekeeping might become inaccurate or fail.
  15 *
  16 * For many system the exact clockrate of the timer isn't known but due to
  17 * the way this value is used we can get away with a wrong value as long
  18 * as this value is:
  19 *
  20 *  - a multiple of HZ
  21 *  - a divisor of the actual rate
  22 *
  23 * 500000 is a good such cheat value.
  24 *
  25 * The obscure number 1193182 is the same as used by the original i8254
  26 * time in legacy PC hardware; the chip is never found in AVR32 systems.
  27 */
  28#define CLOCK_TICK_RATE         500000  /* Underlying HZ */
  29
  30typedef unsigned long cycles_t;
  31
  32static inline cycles_t get_cycles (void)
  33{
  34        return 0;
  35}
  36
  37extern int read_current_timer(unsigned long *timer_value);
  38#define ARCH_HAS_READ_CURRENT_TIMER     1
  39
  40#endif /* __ASM_AVR32_TIMEX_H */
  41