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, <gj@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 <arm926ejs.h>
  42
  43 typedef volatile struct {
  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 } davinci_timer;
  56
  57 davinci_timer           *timer = (davinci_timer *)CONFIG_SYS_TIMERBASE;
  58
  59 #define TIMER_LOAD_VAL  (CONFIG_SYS_HZ_CLOCK / CONFIG_SYS_HZ)
  60 #define TIM_CLK_DIV     16
  61
  62 static ulong timestamp;
  63 static ulong lastinc;
  64
  65 int timer_init(void)
  66 {
  67         /* We are using timer34 in unchained 32-bit mode, full speed */
  68         timer->tcr = 0x0;
  69         timer->tgcr = 0x0;
  70         timer->tgcr = 0x06 | ((TIM_CLK_DIV - 1) << 8);
  71         timer->tim34 = 0x0;
  72         timer->prd34 = TIMER_LOAD_VAL;
  73         lastinc = 0;
  74         timestamp = 0;
  75         timer->tcr = 2 << 22;
  76
  77         return(0);
  78 }
  79
  80 void reset_timer(void)
  81 {
  82         timer->tcr = 0x0;
  83         timer->tim34 = 0;
  84         lastinc = 0;
  85         timestamp = 0;
  86         timer->tcr = 2 << 22;
  87 }
  88
  89 static ulong get_timer_raw(void)
  90 {
  91         ulong now = timer->tim34;
  92
  93         if (now >= lastinc) {
  94                 /* normal mode */
  95                 timestamp += now - lastinc;
  96         } else {
  97                 /* overflow ... */
  98                 timestamp += now + TIMER_LOAD_VAL - lastinc;
  99         }
 100         lastinc = now;
 101         return timestamp;
 102 }
 103
 104 ulong get_timer(ulong base)
 105 {
 106         return((get_timer_raw() / (TIMER_LOAD_VAL / TIM_CLK_DIV)) - base);
 107 }
 108
 109 void set_timer(ulong t)
 110 {
 111         timestamp = t;
 112 }
 113
 114 void udelay(unsigned long usec)
 115 {
 116         ulong tmo;
 117         ulong endtime;
 118         signed long diff;
 119
 120         tmo = CONFIG_SYS_HZ_CLOCK / 1000;
 121         tmo *= usec;
 122         tmo /= (1000 * TIM_CLK_DIV);
 123
 124         endtime = get_timer_raw() + tmo;
 125
 126         do {
 127                 ulong now = get_timer_raw();
 128                 diff = endtime - now;
 129         } while (diff >= 0);
 130 }
 131
 132 /*
 133  * This function is derived from PowerPC code (read timebase as long long).
 134  * On ARM it just returns the timer value.
 135  */
 136 unsigned long long get_ticks(void)
 137 {
 138         return(get_timer(0));
 139 }
 140
 141 /*
 142  * This function is derived from PowerPC code (timebase clock frequency).
 143  * On ARM it returns the number of timer ticks per second.
 144  */
 145 ulong get_tbclk(void)
 146 {
 147         return CONFIG_SYS_HZ;
 148 }