cpu/sh3/time.c

   1 /*
   2  * (C) Copyright 2007
   3  * Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
   4  *
   5  * (C) Copyright 2007
   6  * Nobobuhiro Iwamatsu <iwamatsu@nigauri.org>
   7  *
   8  * (C) Copyright 2003
   9  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  10  *
  11  * See file CREDITS for list of people who contributed to this
  12  * project.
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License as
  16  * published by the Free Software Foundation; either version 2 of
  17  * the License, or (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  27  * MA 02111-1307 USA
  28  */
  29
  30 #include <common.h>
  31 #include <asm/processor.h>
  32 #include <asm/io.h>
  33
  34 #define TMU_MAX_COUNTER (~0UL)
  35
  36 static void tmu_timer_start(unsigned int timer)
  37 {
  38         if (timer > 2)
  39                 return;
  40
  41         outb(inb(TSTR) | (1 << timer), TSTR);
  42 }
  43
  44 static void tmu_timer_stop(unsigned int timer)
  45 {
  46         u8 val = inb(TSTR);
  47
  48         if (timer > 2)
  49                 return;
  50         outb(val & ~(1 << timer), TSTR);
  51 }
  52
  53 int timer_init(void)
  54 {
  55         /* Divide clock by 4 */
  56         outw(0, TCR0);
  57
  58         tmu_timer_stop(0);
  59         tmu_timer_start(0);
  60         return 0;
  61 }
  62
  63 /*
  64    In theory we should return a true 64bit value (ie something that doesn't
  65    overflow). However, we don't. Therefore if TMU runs at fastest rate of
  66    6.75 MHz this value will wrap after u-boot has been running for approx
  67    10 minutes.
  68 */
  69 unsigned long long get_ticks(void)
  70 {
  71         return (0 - inl(TCNT0));
  72 }
  73
  74 unsigned long get_timer(unsigned long base)
  75 {
  76         return ((0 - inl(TCNT0)) - base);
  77 }
  78
  79 void set_timer(unsigned long t)
  80 {
  81         outl(0 - t, TCNT0);
  82 }
  83
  84 void reset_timer(void)
  85 {
  86         tmu_timer_stop(0);
  87         set_timer(0);
  88         tmu_timer_start(0);
  89 }
  90
  91 void udelay(unsigned long usec)
  92 {
  93         unsigned int start = get_timer(0);
  94         unsigned int end = start + (usec * ((CONFIG_SYS_HZ + 500000) / 1000000));
  95
  96         while (get_timer(0) < end)
  97                 continue;
  98 }
  99
 100 unsigned long get_tbclk(void)
 101 {
 102         return CONFIG_SYS_HZ;
 103 }