LXR uboot/arch/arm/cpu/armv7/s5p-common/timer.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Copyright (C) 2009 Samsung Electronics
   4 * Heungjun Kim <riverful.kim@samsung.com>
   5 * Inki Dae <inki.dae@samsung.com>
   6 * Minkyu Kang <mk7.kang@samsung.com>
   7 */
   8
   9#include <common.h>
  10#include <div64.h>
  11#include <init.h>
  12#include <time.h>
  13#include <asm/global_data.h>
  14#include <asm/io.h>
  15#include <asm/arch/pwm.h>
  16#include <asm/arch/clk.h>
  17#include <linux/delay.h>
  18
  19/* Use the old PWM interface for now */
  20#undef CONFIG_DM_PWM
  21#include <pwm.h>
  22
  23DECLARE_GLOBAL_DATA_PTR;
  24
  25unsigned long get_current_tick(void);
  26static void reset_timer_masked(void);
  27
  28/* macro to read the 16 bit timer */
  29static inline struct s5p_timer *s5p_get_base_timer(void)
  30{
  31        return (struct s5p_timer *)samsung_get_base_timer();
  32}
  33
  34/**
  35 * Read the countdown timer.
  36 *
  37 * This operates at 1MHz and counts downwards. It will wrap about every
  38 * hour (2^32 microseconds).
  39 *
  40 * @return current value of timer
  41 */
  42static unsigned long timer_get_us_down(void)
  43{
  44        struct s5p_timer *const timer = s5p_get_base_timer();
  45
  46        return readl(&timer->tcnto4);
  47}
  48
  49int timer_init(void)
  50{
  51        /* PWM Timer 4 */
  52        pwm_init(4, MUX_DIV_4, 0);
  53        pwm_config(4, 100000, 100000);
  54        pwm_enable(4);
  55
  56        /* Use this as the current monotonic time in us */
  57        gd->arch.timer_reset_value = 0;
  58
  59        /* Use this as the last timer value we saw */
  60        gd->arch.lastinc = timer_get_us_down();
  61        reset_timer_masked();
  62
  63        return 0;
  64}
  65
  66/*
  67 * timer without interrupts
  68 */
  69unsigned long get_timer(unsigned long base)
  70{
  71        unsigned long long time_ms;
  72
  73        ulong now = timer_get_us_down();
  74
  75        /*
  76         * Increment the time by the amount elapsed since the last read.
  77         * The timer may have wrapped around, but it makes no difference to
  78         * our arithmetic here.
  79         */
  80        gd->arch.timer_reset_value += gd->arch.lastinc - now;
  81        gd->arch.lastinc = now;
  82
  83        /* Divide by 1000 to convert from us to ms */
  84        time_ms = gd->arch.timer_reset_value;
  85        do_div(time_ms, 1000);
  86        return time_ms - base;
  87}
  88
  89unsigned long __attribute__((no_instrument_function)) timer_get_us(void)
  90{
  91        static unsigned long base_time_us;
  92
  93        struct s5p_timer *const timer =
  94                (struct s5p_timer *)samsung_get_base_timer();
  95        unsigned long now_downward_us = readl(&timer->tcnto4);
  96
  97        if (!base_time_us)
  98                base_time_us = now_downward_us;
  99
 100        /* Note that this timer counts downward. */
 101        return base_time_us - now_downward_us;
 102}
 103
 104/* delay x useconds */
 105void __udelay(unsigned long usec)
 106{
 107        unsigned long count_value;
 108
 109        count_value = timer_get_us_down();
 110        while ((int)(count_value - timer_get_us_down()) < (int)usec)
 111                ;
 112}
 113
 114static void reset_timer_masked(void)
 115{
 116        struct s5p_timer *const timer = s5p_get_base_timer();
 117
 118        /* reset time */
 119        gd->arch.lastinc = readl(&timer->tcnto4);
 120        gd->arch.tbl = 0;
 121}
 122
 123/*
 124 * This function is derived from PowerPC code (read timebase as long long).
 125 * On ARM it just returns the timer value.
 126 */
 127unsigned long long get_ticks(void)
 128{
 129        return get_timer(0);
 130}
 131
 132/*
 133 * This function is derived from PowerPC code (timebase clock frequency).
 134 * On ARM it returns the number of timer ticks per second.
 135 */
 136unsigned long get_tbclk(void)
 137{
 138        return CONFIG_SYS_HZ;
 139}
 140