LXR uboot/arch/arm/imx-common/timer.c

   1/*
   2 * (C) Copyright 2007
   3 * Sascha Hauer, Pengutronix
   4 *
   5 * (C) Copyright 2009 Freescale Semiconductor, Inc.
   6 *
   7 * See file CREDITS for list of people who contributed to this
   8 * project.
   9 *
  10 * This program is free software; you can redistribute it and/or
  11 * modify it under the terms of the GNU General Public License as
  12 * published by the Free Software Foundation; either version 2 of
  13 * the License, or (at your option) any later version.
  14 *
  15 * This program is distributed in the hope that it will be useful,
  16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 * GNU General Public License for more details.
  19 *
  20 * You should have received a copy of the GNU General Public License
  21 * along with this program; if not, write to the Free Software
  22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  23 * MA 02111-1307 USA
  24 */
  25
  26#include <common.h>
  27#include <asm/io.h>
  28#include <div64.h>
  29#include <asm/arch/imx-regs.h>
  30#include <asm/arch/clock.h>
  31
  32/* General purpose timers registers */
  33struct mxc_gpt {
  34        unsigned int control;
  35        unsigned int prescaler;
  36        unsigned int status;
  37        unsigned int nouse[6];
  38        unsigned int counter;
  39};
  40
  41static struct mxc_gpt *cur_gpt = (struct mxc_gpt *)GPT1_BASE_ADDR;
  42
  43/* General purpose timers bitfields */
  44#define GPTCR_SWR               (1 << 15)       /* Software reset */
  45#define GPTCR_FRR               (1 << 9)        /* Freerun / restart */
  46#define GPTCR_CLKSOURCE_32      (4 << 6)        /* Clock source */
  47#define GPTCR_TEN               1               /* Timer enable */
  48
  49DECLARE_GLOBAL_DATA_PTR;
  50
  51#define timestamp (gd->tbl)
  52#define lastinc (gd->lastinc)
  53
  54static inline unsigned long long tick_to_time(unsigned long long tick)
  55{
  56        tick *= CONFIG_SYS_HZ;
  57        do_div(tick, MXC_CLK32);
  58
  59        return tick;
  60}
  61
  62static inline unsigned long long us_to_tick(unsigned long long usec)
  63{
  64        usec = usec * MXC_CLK32 + 999999;
  65        do_div(usec, 1000000);
  66
  67        return usec;
  68}
  69
  70int timer_init(void)
  71{
  72        int i;
  73        ulong val;
  74
  75        /* setup GP Timer 1 */
  76        __raw_writel(GPTCR_SWR, &cur_gpt->control);
  77
  78        /* We have no udelay by now */
  79        for (i = 0; i < 100; i++)
  80                __raw_writel(0, &cur_gpt->control);
  81
  82        __raw_writel(0, &cur_gpt->prescaler); /* 32Khz */
  83
  84        /* Freerun Mode, PERCLK1 input */
  85        i = __raw_readl(&cur_gpt->control);
  86        __raw_writel(i | GPTCR_CLKSOURCE_32 | GPTCR_TEN, &cur_gpt->control);
  87
  88        val = __raw_readl(&cur_gpt->counter);
  89        lastinc = val / (MXC_CLK32 / CONFIG_SYS_HZ);
  90        timestamp = 0;
  91
  92        return 0;
  93}
  94
  95unsigned long long get_ticks(void)
  96{
  97        ulong now = __raw_readl(&cur_gpt->counter); /* current tick value */
  98
  99        if (now >= lastinc) {
 100                /*
 101                 * normal mode (non roll)
 102                 * move stamp forward with absolut diff ticks
 103                 */
 104                timestamp += (now - lastinc);
 105        } else {
 106                /* we have rollover of incrementer */
 107                timestamp += (0xFFFFFFFF - lastinc) + now;
 108        }
 109        lastinc = now;
 110        return timestamp;
 111}
 112
 113ulong get_timer_masked(void)
 114{
 115        /*
 116         * get_ticks() returns a long long (64 bit), it wraps in
 117         * 2^64 / MXC_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~
 118         * 5 * 10^9 days... and get_ticks() * CONFIG_SYS_HZ wraps in
 119         * 5 * 10^6 days - long enough.
 120         */
 121        return tick_to_time(get_ticks());
 122}
 123
 124ulong get_timer(ulong base)
 125{
 126        return get_timer_masked() - base;
 127}
 128
 129/* delay x useconds AND preserve advance timstamp value */
 130void __udelay(unsigned long usec)
 131{
 132        unsigned long long tmp;
 133        ulong tmo;
 134
 135        tmo = us_to_tick(usec);
 136        tmp = get_ticks() + tmo;        /* get current timestamp */
 137
 138        while (get_ticks() < tmp)       /* loop till event */
 139                 /*NOP*/;
 140}
 141
 142/*
 143 * This function is derived from PowerPC code (timebase clock frequency).
 144 * On ARM it returns the number of timer ticks per second.
 145 */
 146ulong get_tbclk(void)
 147{
 148        return MXC_CLK32;
 149}
 150