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
  42static ulong timestamp;
  43static ulong lastinc;
  44
  45int timer_init (void)
  46{
  47        int32_t val;
  48
  49        /* Start the counter ticking up */
  50        *((int32_t *) (CONFIG_SYS_TIMERBASE + TLDR)) = TIMER_LOAD_VAL;  /* reload value on overflow*/
  51        val = (CONFIG_SYS_PTV << 2) | BIT5 | BIT1 | BIT0;               /* mask to enable timer*/
  52        *((int32_t *) (CONFIG_SYS_TIMERBASE + TCLR)) = val;     /* start timer */
  53
  54        reset_timer_masked(); /* init the timestamp and lastinc value */
  55
  56        return(0);
  57}
  58/*
  59 * timer without interrupts
  60 */
  61void reset_timer (void)
  62{
  63        reset_timer_masked ();
  64}
  65
  66ulong get_timer (ulong base)
  67{
  68        return get_timer_masked () - base;
  69}
  70
  71void set_timer (ulong t)
  72{
  73        timestamp = t;
  74}
  75
  76/* delay x useconds AND preserve advance timestamp value */
  77void __udelay (unsigned long usec)
  78{
  79        ulong tmo, tmp;
  80
  81        if (usec >= 1000) {             /* if "big" number, spread normalization to seconds */
  82                tmo = usec / 1000;      /* start to normalize for usec to ticks per sec */
  83                tmo *= CONFIG_SYS_HZ;   /* find number of "ticks" to wait to achieve target */
  84                tmo /= 1000;            /* finish normalize. */
  85        } else {                        /* else small number, don't kill it prior to HZ multiply */
  86                tmo = usec * CONFIG_SYS_HZ;
  87                tmo /= (1000*1000);
  88        }
  89
  90        tmp = get_timer (0);            /* get current timestamp */
  91        if ( (tmo + tmp + 1) < tmp )    /* if setting this forward will roll time stamp */
  92                reset_timer_masked ();  /* reset "advancing" timestamp to 0, set lastinc value */
  93        else
  94                tmo     += tmp;         /* else, set advancing stamp wake up time */
  95        while (get_timer_masked () < tmo)/* loop till event */
  96                /*NOP*/;
  97}
  98
  99void reset_timer_masked (void)
 100{
 101        /* reset time */
 102        lastinc = READ_TIMER;           /* capture current incrementer value time */
 103        timestamp = 0;                  /* start "advancing" time stamp from 0 */
 104}
 105
 106ulong get_timer_masked (void)
 107{
 108        ulong now = READ_TIMER;         /* current tick value */
 109
 110        if (now >= lastinc)             /* normal mode (non roll) */
 111                timestamp += (now - lastinc); /* move stamp fordward with absoulte diff ticks */
 112        else                            /* we have rollover of incrementer */
 113                timestamp += (0xFFFFFFFF - lastinc) + now;
 114        lastinc = now;
 115        return timestamp;
 116}
 117
 118/* waits specified delay value and resets timestamp */
 119void udelay_masked (unsigned long usec)
 120{
 121        ulong tmo;
 122        ulong endtime;
 123        signed long diff;
 124
 125        if (usec >= 1000) {                     /* if "big" number, spread normalization to seconds */
 126                tmo = usec / 1000;              /* start to normalize for usec to ticks per sec */
 127                tmo *= CONFIG_SYS_HZ;                   /* find number of "ticks" to wait to achieve target */
 128                tmo /= 1000;                    /* finish normalize. */
 129        } else {                                        /* else small number, don't kill it prior to HZ multiply */
 130                tmo = usec * CONFIG_SYS_HZ;
 131                tmo /= (1000*1000);
 132        }
 133        endtime = get_timer_masked () + tmo;
 134
 135        do {
 136                ulong now = get_timer_masked ();
 137                diff = endtime - now;
 138        } while (diff >= 0);
 139}
 140
 141/*
 142 * This function is derived from PowerPC code (read timebase as long long).
 143 * On ARM it just returns the timer value.
 144 */
 145unsigned long long get_ticks(void)
 146{
 147        return get_timer(0);
 148}
 149/*
 150 * This function is derived from PowerPC code (timebase clock frequency).
 151 * On ARM it returns the number of timer ticks per second.
 152 */
 153ulong get_tbclk (void)
 154{
 155        ulong tbclk;
 156        tbclk = CONFIG_SYS_HZ;
 157        return tbclk;
 158}
 159