LXR uboot/arch/arm/cpu/armv7/tegra2/timer.c

   1/*
   2 * (C) Copyright 2010,2011
   3 * NVIDIA Corporation <www.nvidia.com>
   4 *
   5 * (C) Copyright 2008
   6 * Texas Instruments
   7 *
   8 * Richard Woodruff <r-woodruff2@ti.com>
   9 * Syed Moahmmed Khasim <khasim@ti.com>
  10 *
  11 * (C) Copyright 2002
  12 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  13 * Marius Groeger <mgroeger@sysgo.de>
  14 * Alex Zuepke <azu@sysgo.de>
  15 *
  16 * (C) Copyright 2002
  17 * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
  18 *
  19 * See file CREDITS for list of people who contributed to this
  20 * project.
  21 *
  22 * This program is free software; you can redistribute it and/or
  23 * modify it under the terms of the GNU General Public License as
  24 * published by the Free Software Foundation; either version 2 of
  25 * the License, or (at your option) any later version.
  26 *
  27 * This program is distributed in the hope that it will be useful,
  28 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  29 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  30 * GNU General Public License for more details.
  31 *
  32 * You should have received a copy of the GNU General Public License
  33 * along with this program; if not, write to the Free Software
  34 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  35 * MA 02111-1307 USA
  36 */
  37
  38#include <common.h>
  39#include <asm/io.h>
  40#include <asm/arch/tegra2.h>
  41#include <asm/arch/timer.h>
  42
  43DECLARE_GLOBAL_DATA_PTR;
  44
  45/* counter runs at 1MHz */
  46#define TIMER_CLK       1000000
  47#define TIMER_LOAD_VAL  0xffffffff
  48
  49/* timer without interrupts */
  50ulong get_timer(ulong base)
  51{
  52        return get_timer_masked() - base;
  53}
  54
  55/* delay x useconds */
  56void __udelay(unsigned long usec)
  57{
  58        long tmo = usec * (TIMER_CLK / 1000) / 1000;
  59        unsigned long now, last = timer_get_us();
  60
  61        while (tmo > 0) {
  62                now = timer_get_us();
  63                if (last > now) /* count up timer overflow */
  64                        tmo -= TIMER_LOAD_VAL - last + now;
  65                else
  66                        tmo -= now - last;
  67                last = now;
  68        }
  69}
  70
  71ulong get_timer_masked(void)
  72{
  73        ulong now;
  74
  75        /* current tick value */
  76        now = timer_get_us() / (TIMER_CLK / CONFIG_SYS_HZ);
  77
  78        if (now >= gd->lastinc) /* normal mode (non roll) */
  79                /* move stamp forward with absolute diff ticks */
  80                gd->tbl += (now - gd->lastinc);
  81        else    /* we have rollover of incrementer */
  82                gd->tbl += ((TIMER_LOAD_VAL / (TIMER_CLK / CONFIG_SYS_HZ))
  83                                - gd->lastinc) + now;
  84        gd->lastinc = now;
  85        return gd->tbl;
  86}
  87
  88/*
  89 * This function is derived from PowerPC code (read timebase as long long).
  90 * On ARM it just returns the timer value.
  91 */
  92unsigned long long get_ticks(void)
  93{
  94        return get_timer(0);
  95}
  96
  97/*
  98 * This function is derived from PowerPC code (timebase clock frequency).
  99 * On ARM it returns the number of timer ticks per second.
 100 */
 101ulong get_tbclk(void)
 102{
 103        return CONFIG_SYS_HZ;
 104}
 105
 106unsigned long timer_get_us(void)
 107{
 108        struct timerus *timer_base = (struct timerus *)NV_PA_TMRUS_BASE;
 109
 110        return readl(&timer_base->cntr_1us);
 111}
 112