LXR linux/arch/avr32/lib/delay.c

   1/*
   2 *      Precise Delay Loops for avr32
   3 *
   4 *      Copyright (C) 1993 Linus Torvalds
   5 *      Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
   6 *      Copyright (C) 2005-2006 Atmel Corporation
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License version 2 as
  10 * published by the Free Software Foundation.
  11 */
  12
  13#include <linux/delay.h>
  14#include <linux/module.h>
  15#include <linux/timex.h>
  16#include <linux/param.h>
  17#include <linux/types.h>
  18#include <linux/init.h>
  19
  20#include <asm/processor.h>
  21#include <asm/sysreg.h>
  22
  23int __devinit read_current_timer(unsigned long *timer_value)
  24{
  25        *timer_value = sysreg_read(COUNT);
  26        return 0;
  27}
  28
  29void __delay(unsigned long loops)
  30{
  31        unsigned bclock, now;
  32
  33        bclock = sysreg_read(COUNT);
  34        do {
  35                now = sysreg_read(COUNT);
  36        } while ((now - bclock) < loops);
  37}
  38
  39inline void __const_udelay(unsigned long xloops)
  40{
  41        unsigned long long loops;
  42
  43        asm("mulu.d %0, %1, %2"
  44            : "=r"(loops)
  45            : "r"(current_cpu_data.loops_per_jiffy * HZ), "r"(xloops));
  46        __delay(loops >> 32);
  47}
  48
  49void __udelay(unsigned long usecs)
  50{
  51        __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
  52}
  53
  54void __ndelay(unsigned long nsecs)
  55{
  56        __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
  57}
  58