cpu/arm926ejs/davinci/timer.c

   1 /*
   2  * (C) Copyright 2003
   3  * Texas Instruments <www.ti.com>
   4  *
   5  * (C) Copyright 2002
   6  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   7  * Marius Groeger <mgroeger@sysgo.de>
   8  *
   9  * (C) Copyright 2002
  10  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  11  * Alex Zuepke <azu@sysgo.de>
  12  *
  13  * (C) Copyright 2002-2004
  14  * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
  15  *
  16  * (C) Copyright 2004
  17  * Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
  18  *
  19  * Copyright (C) 2007 Sergey Kubushyn <ksi@koi8.net>
  20  *
  21  * See file CREDITS for list of people who contributed to this
  22  * project.
  23  *
  24  * This program is free software; you can redistribute it and/or
  25  * modify it under the terms of the GNU General Public License as
  26  * published by the Free Software Foundation; either version 2 of
  27  * the License, or (at your option) any later version.
  28  *
  29  * This program is distributed in the hope that it will be useful,
  30  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  31  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  32  * GNU General Public License for more details.
  33  *
  34  * You should have received a copy of the GNU General Public License
  35  * along with this program; if not, write to the Free Software
  36  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  37  * MA 02111-1307 USA
  38  */
  39
  40 #include <common.h>
  41 #include <asm/io.h>
  42
  43 struct davinci_timer {
  44         u_int32_t       pid12;
  45         u_int32_t       emumgt;
  46         u_int32_t       na1;
  47         u_int32_t       na2;
  48         u_int32_t       tim12;
  49         u_int32_t       tim34;
  50         u_int32_t       prd12;
  51         u_int32_t       prd34;
  52         u_int32_t       tcr;
  53         u_int32_t       tgcr;
  54         u_int32_t       wdtcr;
  55 };
  56
  57 static struct davinci_timer * const timer =
  58         (struct davinci_timer *)CONFIG_SYS_TIMERBASE;
  59
  60 #define TIMER_LOAD_VAL  (CONFIG_SYS_HZ_CLOCK / CONFIG_SYS_HZ)
  61 #define TIM_CLK_DIV     16
  62
  63 static ulong timestamp;
  64 static ulong lastinc;
  65
  66 int timer_init(void)
  67 {
  68         /* We are using timer34 in unchained 32-bit mode, full speed */
  69         writel(0x0, &timer->tcr);
  70         writel(0x0, &timer->tgcr);
  71         writel(0x06 | ((TIM_CLK_DIV - 1) << 8), &timer->tgcr);
  72         writel(0x0, &timer->tim34);
  73         writel(TIMER_LOAD_VAL, &timer->prd34);
  74         lastinc = 0;
  75         timestamp = 0;
  76         writel(2 << 22, &timer->tcr);
  77
  78         return(0);
  79 }
  80
  81 void reset_timer(void)
  82 {
  83         writel(0x0, &timer->tcr);
  84         writel(0x0, &timer->tim34);
  85         lastinc = 0;
  86         timestamp = 0;
  87         writel(2 << 22, &timer->tcr);
  88 }
  89
  90 static ulong get_timer_raw(void)
  91 {
  92         ulong now = readl(&timer->tim34);
  93
  94         if (now >= lastinc) {
  95                 /* normal mode */
  96                 timestamp += now - lastinc;
  97         } else {
  98                 /* overflow ... */
  99                 timestamp += now + TIMER_LOAD_VAL - lastinc;
 100         }
 101         lastinc = now;
 102         return timestamp;
 103 }
 104
 105 ulong get_timer(ulong base)
 106 {
 107         return((get_timer_raw() / (TIMER_LOAD_VAL / TIM_CLK_DIV)) - base);
 108 }
 109
 110 void set_timer(ulong t)
 111 {
 112         timestamp = t;
 113 }
 114
 115 void __udelay(unsigned long usec)
 116 {
 117         ulong tmo;
 118         ulong endtime;
 119         signed long diff;
 120
 121         tmo = CONFIG_SYS_HZ_CLOCK / 1000;
 122         tmo *= usec;
 123         tmo /= (1000 * TIM_CLK_DIV);
 124
 125         endtime = get_timer_raw() + tmo;
 126
 127         do {
 128                 ulong now = get_timer_raw();
 129                 diff = endtime - now;
 130         } while (diff >= 0);
 131 }
 132
 133 /*
 134  * This function is derived from PowerPC code (read timebase as long long).
 135  * On ARM it just returns the timer value.
 136  */
 137 unsigned long long get_ticks(void)
 138 {
 139         return(get_timer(0));
 140 }
 141
 142 /*
 143  * This function is derived from PowerPC code (timebase clock frequency).
 144  * On ARM it returns the number of timer ticks per second.
 145  */
 146 ulong get_tbclk(void)
 147 {
 148         return CONFIG_SYS_HZ;
 149 }