arch/sh/lib/time.c

   1 /*
   2  * (C) Copyright 2009
   3  * Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
   4  *
   5  * (C) Copyright 2007-2010
   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 <div64.h>
  32 #include <asm/processor.h>
  33 #include <asm/clk.h>
  34 #include <asm/io.h>
  35
  36 #define TMU_MAX_COUNTER (~0UL)
  37
  38 static ulong timer_freq;
  39 static unsigned long last_tcnt;
  40 static unsigned long long overflow_ticks;
  41
  42 static inline unsigned long long tick_to_time(unsigned long long tick)
  43 {
  44         tick *= CONFIG_SYS_HZ;
  45         do_div(tick, timer_freq);
  46
  47         return tick;
  48 }
  49
  50 static inline unsigned long long usec_to_tick(unsigned long long usec)
  51 {
  52         usec *= timer_freq;
  53         do_div(usec, 1000000);
  54
  55         return usec;
  56 }
  57
  58 static void tmu_timer_start (unsigned int timer)
  59 {
  60         if (timer > 2)
  61                 return;
  62         writeb(readb(TSTR) | (1 << timer), TSTR);
  63 }
  64
  65 static void tmu_timer_stop (unsigned int timer)
  66 {
  67         if (timer > 2)
  68                 return;
  69         writeb(readb(TSTR) & ~(1 << timer), TSTR);
  70 }
  71
  72 int timer_init (void)
  73 {
  74         /* Divide clock by CONFIG_SYS_TMU_CLK_DIV */
  75         u16 bit = 0;
  76
  77         switch (CONFIG_SYS_TMU_CLK_DIV) {
  78         case 1024:
  79                 bit = 4;
  80                 break;
  81         case 256:
  82                 bit = 3;
  83                 break;
  84         case 64:
  85                 bit = 2;
  86                 break;
  87         case 16:
  88                 bit = 1;
  89                 break;
  90         case 4:
  91         default:
  92                 break;
  93         }
  94         writew(readw(TCR0) | bit, TCR0);
  95
  96         /* Calc clock rate */
  97         timer_freq = get_tmu0_clk_rate() >> ((bit + 1) * 2);
  98
  99         tmu_timer_stop(0);
 100         tmu_timer_start(0);
 101
 102         last_tcnt = 0;
 103         overflow_ticks = 0;
 104
 105         return 0;
 106 }
 107
 108 unsigned long long get_ticks (void)
 109 {
 110         unsigned long tcnt = 0 - readl(TCNT0);
 111         unsigned long ticks;
 112
 113         if (last_tcnt > tcnt) { /* overflow */
 114                 overflow_ticks++;
 115                 ticks = (0xffffffff - last_tcnt) + tcnt;
 116         } else {
 117                 ticks = tcnt;
 118         }
 119         last_tcnt = tcnt;
 120
 121         return (overflow_ticks << 32) | tcnt;
 122 }
 123
 124 void __udelay (unsigned long usec)
 125 {
 126         unsigned long long tmp;
 127         ulong tmo;
 128
 129         tmo = usec_to_tick(usec);
 130         tmp = get_ticks() + tmo;        /* get current timestamp */
 131
 132         while (get_ticks() < tmp)       /* loop till event */
 133                  /*NOP*/;
 134 }
 135
 136 unsigned long get_timer (unsigned long base)
 137 {
 138         /* return msec */
 139         return tick_to_time(get_ticks()) - base;
 140 }
 141
 142 void set_timer (unsigned long t)
 143 {
 144         writel((0 - t), TCNT0);
 145 }
 146
 147 void reset_timer (void)
 148 {
 149         tmu_timer_stop(0);
 150         set_timer (0);
 151         tmu_timer_start(0);
 152 }
 153
 154 unsigned long get_tbclk (void)
 155 {
 156         return timer_freq;
 157 }