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
  23 int __devinit read_current_timer(unsigned long *timer_value)
  24 {
  25         *timer_value = sysreg_read(COUNT);
  26         return 0;
  27 }
  28
  29 void __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
  39 inline 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
  49 void __udelay(unsigned long usecs)
  50 {
  51         __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
  52 }
  53
  54 void __ndelay(unsigned long nsecs)
  55 {
  56         __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
  57 }