include/asm-avr32/timex.h

   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
  30 typedef unsigned long cycles_t;
  31
  32 static inline cycles_t get_cycles (void)
  33 {
  34         return 0;
  35 }
  36
  37 extern int read_current_timer(unsigned long *timer_value);
  38 #define ARCH_HAS_READ_CURRENT_TIMER     1
  39
  40 #endif /* __ASM_AVR32_TIMEX_H */