LXR uboot/arch/arm/cpu/arm1136/omap24xx/timer.c

   1/*
   2 * (C) Copyright 2004
   3 * Texas Instruments
   4 * Richard Woodruff <r-woodruff2@ti.com>
   5 *
   6 * (C) Copyright 2002
   7 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   8 * Marius Groeger <mgroeger@sysgo.de>
   9 * Alex Zuepke <azu@sysgo.de>
  10 *
  11 * (C) Copyright 2002
  12 * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
  13 *
  14 * See file CREDITS for list of people who contributed to this
  15 * project.
  16 *
  17 * This program is free software; you can redistribute it and/or
  18 * modify it under the terms of the GNU General Public License as
  19 * published by the Free Software Foundation; either version 2 of
  20 * the License, or (at your option) any later version.
  21 *
  22 * This program is distributed in the hope that it will be useful,
  23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25 * GNU General Public License for more details.
  26 *
  27 * You should have received a copy of the GNU General Public License
  28 * along with this program; if not, write to the Free Software
  29 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  30 * MA 02111-1307 USA
  31 */
  32
  33#include <common.h>
  34#include <asm/arch/bits.h>
  35#include <asm/arch/omap2420.h>
  36
  37#define TIMER_LOAD_VAL 0
  38
  39/* macro to read the 32 bit timer */
  40#define READ_TIMER (*((volatile ulong *)(CONFIG_SYS_TIMERBASE+TCRR)))
  41
  42DECLARE_GLOBAL_DATA_PTR;
  43
  44int timer_init (void)
  45{
  46        int32_t val;
  47
  48        /* Start the counter ticking up */
  49        *((int32_t *) (CONFIG_SYS_TIMERBASE + TLDR)) = TIMER_LOAD_VAL;  /* reload value on overflow*/
  50        val = (CONFIG_SYS_PTV << 2) | BIT5 | BIT1 | BIT0;               /* mask to enable timer*/
  51        *((int32_t *) (CONFIG_SYS_TIMERBASE + TCLR)) = val;     /* start timer */
  52
  53        reset_timer_masked(); /* init the timestamp and lastinc value */
  54
  55        return(0);
  56}
  57/*
  58 * timer without interrupts
  59 */
  60void reset_timer (void)
  61{
  62        reset_timer_masked ();
  63}
  64
  65ulong get_timer (ulong base)
  66{
  67        return get_timer_masked () - base;
  68}
  69
  70void set_timer (ulong t)
  71{
  72        gd->tbl = t;
  73}
  74
  75/* delay x useconds AND preserve advance timestamp value */
  76void __udelay (unsigned long usec)
  77{
  78        ulong tmo, tmp;
  79
  80        if (usec >= 1000) {             /* if "big" number, spread normalization to seconds */
  81                tmo = usec / 1000;      /* start to normalize for usec to ticks per sec */
  82                tmo *= CONFIG_SYS_HZ;   /* find number of "ticks" to wait to achieve target */
  83                tmo /= 1000;            /* finish normalize. */
  84        } else {                        /* else small number, don't kill it prior to HZ multiply */
  85                tmo = usec * CONFIG_SYS_HZ;
  86                tmo /= (1000*1000);
  87        }
  88
  89        tmp = get_timer (0);            /* get current timestamp */
  90        if ( (tmo + tmp + 1) < tmp )    /* if setting this forward will roll time stamp */
  91                reset_timer_masked ();  /* reset "advancing" timestamp to 0, set lastinc value */
  92        else
  93                tmo     += tmp;         /* else, set advancing stamp wake up time */
  94        while (get_timer_masked () < tmo)/* loop till event */
  95                /*NOP*/;
  96}
  97
  98void reset_timer_masked (void)
  99{
 100        /* reset time */
 101        gd->lastinc = READ_TIMER;       /* capture current incrementer value time */
 102        gd->tbl = 0;                    /* start "advancing" time stamp from 0 */
 103}
 104
 105ulong get_timer_masked (void)
 106{
 107        ulong now = READ_TIMER;         /* current tick value */
 108
 109        if (now >= gd->lastinc)         /* normal mode (non roll) */
 110                gd->tbl += (now - gd->lastinc); /* move stamp fordward with absoulte diff ticks */
 111        else                            /* we have rollover of incrementer */
 112                gd->tbl += (0xFFFFFFFF - gd->lastinc) + now;
 113        gd->lastinc = now;
 114        return gd->tbl;
 115}
 116
 117/* waits specified delay value and resets timestamp */
 118void udelay_masked (unsigned long usec)
 119{
 120        ulong tmo;
 121        ulong endtime;
 122        signed long diff;
 123
 124        if (usec >= 1000) {                     /* if "big" number, spread normalization to seconds */
 125                tmo = usec / 1000;              /* start to normalize for usec to ticks per sec */
 126                tmo *= CONFIG_SYS_HZ;                   /* find number of "ticks" to wait to achieve target */
 127                tmo /= 1000;                    /* finish normalize. */
 128        } else {                                        /* else small number, don't kill it prior to HZ multiply */
 129                tmo = usec * CONFIG_SYS_HZ;
 130                tmo /= (1000*1000);
 131        }
 132        endtime = get_timer_masked () + tmo;
 133
 134        do {
 135                ulong now = get_timer_masked ();
 136                diff = endtime - now;
 137        } while (diff >= 0);
 138}
 139
 140/*
 141 * This function is derived from PowerPC code (read timebase as long long).
 142 * On ARM it just returns the timer value.
 143 */
 144unsigned long long get_ticks(void)
 145{
 146        return get_timer(0);
 147}
 148/*
 149 * This function is derived from PowerPC code (timebase clock frequency).
 150 * On ARM it returns the number of timer ticks per second.
 151 */
 152ulong get_tbclk (void)
 153{
 154        ulong tbclk;
 155        tbclk = CONFIG_SYS_HZ;
 156        return tbclk;
 157}
 158