LXR uboot/arch/arm/cpu/s3c44b0/timer.c

   1/*
   2 * (C) Copyright 2004
   3 * DAVE Srl
   4 * http://www.dave-tech.it
   5 * http://www.wawnet.biz
   6 * mailto:info@wawnet.biz
   7 *
   8 * See file CREDITS for list of people who contributed to this
   9 * project.
  10 *
  11 * This program is free software; you can redistribute it and/or
  12 * modify it under the terms of the GNU General Public License as
  13 * published by the Free Software Foundation; either version 2 of
  14 * the License, or (at your option) any later version.
  15 *
  16 * This program is distributed in the hope that it will be useful,
  17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 * GNU General Public License for more details.
  20 *
  21 * You should have received a copy of the GNU General Public License
  22 * along with this program; if not, write to the Free Software
  23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  24 * MA 02111-1307 USA
  25 */
  26
  27#include <common.h>
  28#include <asm/hardware.h>
  29
  30/* we always count down the max. */
  31#define TIMER_LOAD_VAL 0xffff
  32
  33/* macro to read the 16 bit timer */
  34#define READ_TIMER (TCNTO1 & 0xffff)
  35
  36#ifdef CONFIG_USE_IRQ
  37#error CONFIG_USE_IRQ NOT supported
  38#endif
  39
  40static ulong timestamp;
  41static ulong lastdec;
  42
  43int timer_init (void)
  44{
  45        TCFG0 = 0x000000E9;
  46        TCFG1 = 0x00000004;
  47        TCON = 0x00000900;
  48        TCNTB1 = TIMER_LOAD_VAL;
  49        TCMPB1 = 0;
  50        TCON = 0x00000B00;
  51        TCON = 0x00000900;
  52
  53
  54        lastdec = TCNTB1 = TIMER_LOAD_VAL;
  55        timestamp = 0;
  56        return 0;
  57}
  58
  59/*
  60 * timer without interrupts
  61 */
  62
  63void reset_timer (void)
  64{
  65        reset_timer_masked ();
  66}
  67
  68ulong get_timer (ulong base)
  69{
  70        return get_timer_masked () - base;
  71}
  72
  73void set_timer (ulong t)
  74{
  75        timestamp = t;
  76}
  77
  78void __udelay (unsigned long usec)
  79{
  80        ulong tmo;
  81
  82        tmo = usec / 1000;
  83        tmo *= CONFIG_SYS_HZ;
  84        tmo /= 8;
  85
  86        tmo += get_timer (0);
  87
  88        while (get_timer_masked () < tmo)
  89                /*NOP*/;
  90}
  91
  92void reset_timer_masked (void)
  93{
  94        /* reset time */
  95        lastdec = READ_TIMER;
  96        timestamp = 0;
  97}
  98
  99ulong get_timer_masked (void)
 100{
 101        ulong now = READ_TIMER;
 102
 103        if (lastdec >= now) {
 104                /* normal mode */
 105                timestamp += lastdec - now;
 106        } else {
 107                /* we have an overflow ... */
 108                timestamp += lastdec + TIMER_LOAD_VAL - now;
 109        }
 110        lastdec = now;
 111
 112        return timestamp;
 113}
 114
 115void udelay_masked (unsigned long usec)
 116{
 117        ulong tmo;
 118        ulong endtime;
 119        signed long diff;
 120
 121        if (usec >= 1000) {
 122                tmo = usec / 1000;
 123                tmo *= CONFIG_SYS_HZ;
 124                tmo /= 8;
 125        } else {
 126                tmo = usec * CONFIG_SYS_HZ;
 127                tmo /= (1000*8);
 128        }
 129
 130        endtime = get_timer(0) + tmo;
 131
 132        do {
 133                ulong now = get_timer_masked ();
 134                diff = endtime - now;
 135        } while (diff >= 0);
 136}
 137