lib_mips/time.c

   1 /*
   2  * (C) Copyright 2003
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  */
  23
  24 #include <common.h>
  25
  26
  27 static inline void mips_compare_set(u32 v)
  28 {
  29         asm volatile ("mtc0 %0, $11" : : "r" (v));
  30 }
  31
  32 static inline void mips_count_set(u32 v)
  33 {
  34         asm volatile ("mtc0 %0, $9" : : "r" (v));
  35 }
  36
  37
  38 static inline u32 mips_count_get(void)
  39 {
  40         u32 count;
  41
  42         asm volatile ("mfc0 %0, $9" : "=r" (count) :);
  43         return count;
  44 }
  45
  46 /*
  47  * timer without interrupts
  48  */
  49
  50 int timer_init(void)
  51 {
  52         mips_compare_set(0);
  53         mips_count_set(0);
  54
  55         return 0;
  56 }
  57
  58 void reset_timer(void)
  59 {
  60         mips_count_set(0);
  61 }
  62
  63 ulong get_timer(ulong base)
  64 {
  65         return mips_count_get() - base;
  66 }
  67
  68 void set_timer(ulong t)
  69 {
  70         mips_count_set(t);
  71 }
  72
  73 void udelay (unsigned long usec)
  74 {
  75         ulong tmo;
  76         ulong start = get_timer(0);
  77
  78         tmo = usec * (CFG_HZ / 1000000);
  79         while ((ulong)((mips_count_get() - start)) < tmo)
  80                 /*NOP*/;
  81 }
  82
  83 /*
  84  * This function is derived from PowerPC code (read timebase as long long).
  85  * On MIPS it just returns the timer value.
  86  */
  87 unsigned long long get_ticks(void)
  88 {
  89         return mips_count_get();
  90 }
  91
  92 /*
  93  * This function is derived from PowerPC code (timebase clock frequency).
  94  * On MIPS it returns the number of timer ticks per second.
  95  */
  96 ulong get_tbclk(void)
  97 {
  98         return CFG_HZ;
  99 }