LXR uboot/arch/arm/cpu/arm920t/a320/timer.c

   1/*
   2 * (C) Copyright 2009 Faraday Technology
   3 * Po-Yu Chuang <ratbert@faraday-tech.com>
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License as published by
   7 * the Free Software Foundation; either version 2 of the License, or
   8 * (at your option) any later version.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program; if not, write to the Free Software
  17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20#include <common.h>
  21#include <div64.h>
  22#include <asm/io.h>
  23#include <faraday/ftpmu010.h>
  24#include <faraday/fttmr010.h>
  25
  26DECLARE_GLOBAL_DATA_PTR;
  27
  28#define TIMER_CLOCK     32768
  29#define TIMER_LOAD_VAL  0xffffffff
  30
  31static inline unsigned long long tick_to_time(unsigned long long tick)
  32{
  33        tick *= CONFIG_SYS_HZ;
  34        do_div(tick, gd->arch.timer_rate_hz);
  35
  36        return tick;
  37}
  38
  39static inline unsigned long long usec_to_tick(unsigned long long usec)
  40{
  41        usec *= gd->arch.timer_rate_hz;
  42        do_div(usec, 1000000);
  43
  44        return usec;
  45}
  46
  47int timer_init(void)
  48{
  49        struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE;
  50        unsigned int cr;
  51
  52        debug("%s()\n", __func__);
  53
  54        /* disable timers */
  55        writel(0, &tmr->cr);
  56
  57        /* use 32768Hz oscillator for RTC, WDT, TIMER */
  58        ftpmu010_32768osc_enable();
  59
  60        /* setup timer */
  61        writel(TIMER_LOAD_VAL, &tmr->timer3_load);
  62        writel(TIMER_LOAD_VAL, &tmr->timer3_counter);
  63        writel(0, &tmr->timer3_match1);
  64        writel(0, &tmr->timer3_match2);
  65
  66        /* we don't want timer to issue interrupts */
  67        writel(FTTMR010_TM3_MATCH1 |
  68               FTTMR010_TM3_MATCH2 |
  69               FTTMR010_TM3_OVERFLOW,
  70               &tmr->interrupt_mask);
  71
  72        cr = readl(&tmr->cr);
  73        cr |= FTTMR010_TM3_CLOCK;       /* use external clock */
  74        cr |= FTTMR010_TM3_ENABLE;
  75        writel(cr, &tmr->cr);
  76
  77        gd->arch.timer_rate_hz = TIMER_CLOCK;
  78        gd->arch.tbu = gd->arch.tbl = 0;
  79
  80        return 0;
  81}
  82
  83/*
  84 * Get the current 64 bit timer tick count
  85 */
  86unsigned long long get_ticks(void)
  87{
  88        struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE;
  89        ulong now = TIMER_LOAD_VAL - readl(&tmr->timer3_counter);
  90
  91        /* increment tbu if tbl has rolled over */
  92        if (now < gd->arch.tbl)
  93                gd->arch.tbu++;
  94        gd->arch.tbl = now;
  95        return (((unsigned long long)gd->arch.tbu) << 32) | gd->arch.tbl;
  96}
  97
  98void __udelay(unsigned long usec)
  99{
 100        unsigned long long start;
 101        ulong tmo;
 102
 103        start = get_ticks();            /* get current timestamp */
 104        tmo = usec_to_tick(usec);       /* convert usecs to ticks */
 105        while ((get_ticks() - start) < tmo)
 106                ;                       /* loop till time has passed */
 107}
 108
 109/*
 110 * get_timer(base) can be used to check for timeouts or
 111 * to measure elasped time relative to an event:
 112 *
 113 * ulong start_time = get_timer(0) sets start_time to the current
 114 * time value.
 115 * get_timer(start_time) returns the time elapsed since then.
 116 *
 117 * The time is used in CONFIG_SYS_HZ units!
 118 */
 119ulong get_timer(ulong base)
 120{
 121        return tick_to_time(get_ticks()) - base;
 122}
 123
 124/*
 125 * Return the number of timer ticks per second.
 126 */
 127ulong get_tbclk(void)
 128{
 129        return gd->arch.timer_rate_hz;
 130}
 131