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

   1/*
   2 * (C) Copyright 2010
   3 * Michael Schwingen, michael@schwingen.org
   4 *
   5 * (C) Copyright 2006
   6 * Stefan Roese, DENX Software Engineering, sr@denx.de.
   7 *
   8 * (C) Copyright 2002
   9 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  10 * Marius Groeger <mgroeger@sysgo.de>
  11 *
  12 * (C) Copyright 2002
  13 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  14 * Alex Zuepke <azu@sysgo.de>
  15 *
  16 * See file CREDITS for list of people who contributed to this
  17 * project.
  18 *
  19 * This program is free software; you can redistribute it and/or
  20 * modify it under the terms of the GNU General Public License as
  21 * published by the Free Software Foundation; either version 2 of
  22 * the License, or (at your option) any later version.
  23 *
  24 * This program is distributed in the hope that it will be useful,
  25 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  27 * GNU General Public License for more details.
  28 *
  29 * You should have received a copy of the GNU General Public License
  30 * along with this program; if not, write to the Free Software
  31 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  32 * MA 02111-1307 USA
  33 */
  34
  35#include <common.h>
  36#include <asm/arch/ixp425.h>
  37#include <asm/io.h>
  38#include <div64.h>
  39
  40DECLARE_GLOBAL_DATA_PTR;
  41
  42/*
  43 * The IXP42x time-stamp timer runs at 2*OSC_IN (66.666MHz when using a
  44 * 33.333MHz crystal).
  45 */
  46static inline unsigned long long tick_to_time(unsigned long long tick)
  47{
  48        tick *= CONFIG_SYS_HZ;
  49        do_div(tick, CONFIG_IXP425_TIMER_CLK);
  50        return tick;
  51}
  52
  53static inline unsigned long long time_to_tick(unsigned long long time)
  54{
  55        time *= CONFIG_IXP425_TIMER_CLK;
  56        do_div(time, CONFIG_SYS_HZ);
  57        return time;
  58}
  59
  60static inline unsigned long long us_to_tick(unsigned long long us)
  61{
  62        us = us * CONFIG_IXP425_TIMER_CLK + 999999;
  63        do_div(us, 1000000);
  64        return us;
  65}
  66
  67unsigned long long get_ticks(void)
  68{
  69        ulong now = readl(IXP425_OSTS_B);
  70
  71        if (readl(IXP425_OSST) & IXP425_OSST_TIMER_TS_PEND) {
  72                /* rollover of timestamp timer register */
  73                gd->timestamp += (0xFFFFFFFF - gd->lastinc) + now + 1;
  74                writel(IXP425_OSST_TIMER_TS_PEND, IXP425_OSST);
  75        } else {
  76                /* move stamp forward with absolut diff ticks */
  77                gd->timestamp += (now - gd->lastinc);
  78        }
  79        gd->lastinc = now;
  80        return gd->timestamp;
  81}
  82
  83
  84void reset_timer_masked(void)
  85{
  86        /* capture current timestamp counter */
  87        gd->lastinc = readl(IXP425_OSTS_B);
  88        /* start "advancing" time stamp from 0 */
  89        gd->timestamp = 0;
  90}
  91
  92ulong get_timer_masked(void)
  93{
  94        return tick_to_time(get_ticks());
  95}
  96
  97ulong get_timer(ulong base)
  98{
  99        return get_timer_masked() - base;
 100}
 101
 102/* delay x useconds AND preserve advance timestamp value */
 103void __udelay(unsigned long usec)
 104{
 105        unsigned long long tmp;
 106
 107        tmp = get_ticks() + us_to_tick(usec);
 108
 109        while (get_ticks() < tmp)
 110                ;
 111}
 112
 113int timer_init(void)
 114{
 115        writel(IXP425_OSST_TIMER_TS_PEND, IXP425_OSST);
 116        return 0;
 117}
 118