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

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