LXR uboot/arch/arm/cpu/arm1136/mx35/timer.c

   1/*
   2 * (C) Copyright 2007
   3 * Sascha Hauer, Pengutronix
   4 *
   5 * (C) Copyright 2008-2009 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 <asm/arch/imx-regs.h>
  29
  30/* General purpose timers bitfields */
  31#define GPTCR_SWR       (1<<15) /* Software reset */
  32#define GPTCR_FRR       (1<<9)  /* Freerun / restart */
  33#define GPTCR_CLKSOURCE_32   (0x100<<6) /* Clock source */
  34#define GPTCR_CLKSOURCE_IPG (0x001<<6)  /* Clock source */
  35#define GPTCR_TEN       (1)     /* Timer enable */
  36#define GPTPR_VAL       (66)
  37
  38int timer_init(void)
  39{
  40        int i;
  41        struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR;
  42
  43        /* setup GP Timer 1 */
  44        writel(GPTCR_SWR, &gpt->ctrl);
  45        for (i = 0; i < 100; i++)
  46                writel(0, &gpt->ctrl);  /* We have no udelay by now */
  47
  48        writel(GPTPR_VAL, &gpt->pre);
  49        /* Freerun Mode, PERCLK1 input */
  50        writel(readl(&gpt->ctrl) |
  51                GPTCR_CLKSOURCE_IPG | GPTCR_TEN,
  52                &gpt->ctrl);
  53
  54        return 0;
  55}
  56
  57void reset_timer_masked(void)
  58{
  59        struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR;
  60
  61        writel(0, &gpt->ctrl);
  62        /* Freerun Mode, PERCLK1 input */
  63        writel(GPTCR_CLKSOURCE_IPG | GPTCR_TEN,
  64                &gpt->ctrl);
  65}
  66
  67inline ulong get_timer_masked(void)
  68{
  69
  70        struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR;
  71        ulong val = readl(&gpt->counter);
  72
  73        return val;
  74}
  75
  76void reset_timer(void)
  77{
  78        reset_timer_masked();
  79}
  80
  81ulong get_timer(ulong base)
  82{
  83        ulong tmp;
  84
  85        tmp = get_timer_masked();
  86
  87        if (tmp <= (base * 1000)) {
  88                /* Overflow */
  89                tmp += (0xffffffff -  base);
  90        }
  91
  92        return (tmp / 1000) - base;
  93}
  94
  95void set_timer(ulong t)
  96{
  97}
  98
  99/*
 100 * delay x useconds AND preserve advance timstamp value
 101 * GPTCNT is now supposed to tick 1 by 1 us.
 102 */
 103void __udelay(unsigned long usec)
 104{
 105        ulong tmp;
 106
 107        tmp = get_timer_masked();       /* get current timestamp */
 108
 109        /* if setting this forward will roll time stamp */
 110        if ((usec + tmp + 1) < tmp) {
 111                /* reset "advancing" timestamp to 0, set lastinc value */
 112                reset_timer_masked();
 113        } else {
 114                /* else, set advancing stamp wake up time */
 115                tmp += usec;
 116        }
 117
 118        while (get_timer_masked() < tmp)        /* loop till event */
 119                 /*NOP*/;
 120}
 121