arch/arm/mach-davinci/timer.c

   1 /*
   2  * (C) Copyright 2003
   3  * Texas Instruments <www.ti.com>
   4  *
   5  * (C) Copyright 2002
   6  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   7  * Marius Groeger <mgroeger@sysgo.de>
   8  *
   9  * (C) Copyright 2002
  10  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  11  * Alex Zuepke <azu@sysgo.de>
  12  *
  13  * (C) Copyright 2002-2004
  14  * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
  15  *
  16  * (C) Copyright 2004
  17  * Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
  18  *
  19  * Copyright (C) 2007 Sergey Kubushyn <ksi@koi8.net>
  20  *
  21  * SPDX-License-Identifier:     GPL-2.0+
  22  */
  23
  24 #include <common.h>
  25 #include <asm/io.h>
  26 #include <asm/arch/timer_defs.h>
  27 #include <div64.h>
  28
  29 DECLARE_GLOBAL_DATA_PTR;
  30
  31 static struct davinci_timer * const timer =
  32         (struct davinci_timer *)CONFIG_SYS_TIMERBASE;
  33
  34 #define TIMER_LOAD_VAL  0xffffffff
  35
  36 #define TIM_CLK_DIV     16
  37
  38 int timer_init(void)
  39 {
  40         /* We are using timer34 in unchained 32-bit mode, full speed */
  41         writel(0x0, &timer->tcr);
  42         writel(0x0, &timer->tgcr);
  43         writel(0x06 | ((TIM_CLK_DIV - 1) << 8), &timer->tgcr);
  44         writel(0x0, &timer->tim34);
  45         writel(TIMER_LOAD_VAL, &timer->prd34);
  46         writel(2 << 22, &timer->tcr);
  47         gd->arch.timer_rate_hz = CONFIG_SYS_HZ_CLOCK / TIM_CLK_DIV;
  48         gd->arch.timer_reset_value = 0;
  49
  50         return(0);
  51 }
  52
  53 /*
  54  * Get the current 64 bit timer tick count
  55  */
  56 unsigned long long get_ticks(void)
  57 {
  58         unsigned long now = readl(&timer->tim34);
  59
  60         /* increment tbu if tbl has rolled over */
  61         if (now < gd->arch.tbl)
  62                 gd->arch.tbu++;
  63         gd->arch.tbl = now;
  64
  65         return (((unsigned long long)gd->arch.tbu) << 32) | gd->arch.tbl;
  66 }
  67
  68 ulong get_timer(ulong base)
  69 {
  70         unsigned long long timer_diff;
  71
  72         timer_diff = get_ticks() - gd->arch.timer_reset_value;
  73
  74         return lldiv(timer_diff,
  75                      (gd->arch.timer_rate_hz / CONFIG_SYS_HZ)) - base;
  76 }
  77
  78 void __udelay(unsigned long usec)
  79 {
  80         unsigned long long endtime;
  81
  82         endtime = lldiv((unsigned long long)usec * gd->arch.timer_rate_hz,
  83                         1000000UL);
  84         endtime += get_ticks();
  85
  86         while (get_ticks() < endtime)
  87                 ;
  88 }
  89
  90 /*
  91  * This function is derived from PowerPC code (timebase clock frequency).
  92  * On ARM it returns the number of timer ticks per second.
  93  */
  94 ulong get_tbclk(void)
  95 {
  96         return gd->arch.timer_rate_hz;
  97 }
  98
  99 #ifdef CONFIG_HW_WATCHDOG
 100 static struct davinci_timer * const wdttimer =
 101         (struct davinci_timer *)CONFIG_SYS_WDTTIMERBASE;
 102
 103 /*
 104  * See prufw2.pdf for using Timer as a WDT
 105  */
 106 void davinci_hw_watchdog_enable(void)
 107 {
 108         writel(0x0, &wdttimer->tcr);
 109         writel(0x0, &wdttimer->tgcr);
 110         /* TIMMODE = 2h */
 111         writel(0x08 | 0x03 | ((TIM_CLK_DIV - 1) << 8), &wdttimer->tgcr);
 112         writel(CONFIG_SYS_WDT_PERIOD_LOW, &wdttimer->prd12);
 113         writel(CONFIG_SYS_WDT_PERIOD_HIGH, &wdttimer->prd34);
 114         writel(2 << 22, &wdttimer->tcr);
 115         writel(0x0, &wdttimer->tim12);
 116         writel(0x0, &wdttimer->tim34);
 117         /* set WDEN bit, WDKEY 0xa5c6 */
 118         writel(0xa5c64000, &wdttimer->wdtcr);
 119         /* clear counter register */
 120         writel(0xda7e4000, &wdttimer->wdtcr);
 121 }
 122
 123 void davinci_hw_watchdog_reset(void)
 124 {
 125         writel(0xa5c64000, &wdttimer->wdtcr);
 126         writel(0xda7e4000, &wdttimer->wdtcr);
 127 }
 128 #endif