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
19DECLARE_GLOBAL_DATA_PTR;
20
21unsigned long get_current_tick(void);
22static void reset_timer_masked(void);
23
24/* macro to read the 16 bit timer */
25static inline struct s5p_timer *s5p_get_base_timer(void)
26{
27	return (struct s5p_timer *)samsung_get_base_timer();
28}
29
30/**
31 * Read the countdown timer.
32 *
33 * This operates at 1MHz and counts downwards. It will wrap about every
34 * hour (2^32 microseconds).
35 *
36 * Return: current value of timer
37 */
38static unsigned long timer_get_us_down(void)
39{
40	struct s5p_timer *const timer = s5p_get_base_timer();
41
42	return readl(&timer->tcnto4);
43}
44
45int timer_init(void)
46{
47	/* PWM Timer 4 */
48	s5p_pwm_init(4, MUX_DIV_4, 0);
49	s5p_pwm_config(4, 100000, 100000);
50	s5p_pwm_enable(4);
51
52	/* Use this as the current monotonic time in us */
53	gd->arch.timer_reset_value = 0;
54
55	/* Use this as the last timer value we saw */
56	gd->arch.lastinc = timer_get_us_down();
57	reset_timer_masked();
58
59	return 0;
60}
61
62/*
63 * timer without interrupts
64 */
65unsigned long get_timer(unsigned long base)
66{
67	unsigned long long time_ms;
68
69	ulong now = timer_get_us_down();
70
71	/*
72	 * Increment the time by the amount elapsed since the last read.
73	 * The timer may have wrapped around, but it makes no difference to
74	 * our arithmetic here.
75	 */
76	gd->arch.timer_reset_value += gd->arch.lastinc - now;
77	gd->arch.lastinc = now;
78
79	/* Divide by 1000 to convert from us to ms */
80	time_ms = gd->arch.timer_reset_value;
81	do_div(time_ms, 1000);
82	return time_ms - base;
83}
84
85unsigned long notrace timer_get_us(void)
86{
87	static unsigned long base_time_us;
88
89	struct s5p_timer *const timer =
90		(struct s5p_timer *)samsung_get_base_timer();
91	unsigned long now_downward_us = readl(&timer->tcnto4);
92
93	if (!base_time_us)
94		base_time_us = now_downward_us;
95
96	/* Note that this timer counts downward. */
97	return base_time_us - now_downward_us;
98}
99
100/* delay x useconds */
101void __udelay(unsigned long usec)
102{
103	unsigned long count_value;
104
105	count_value = timer_get_us_down();
106	while ((int)(count_value - timer_get_us_down()) < (int)usec)
107		;
108}
109
110static void reset_timer_masked(void)
111{
112	struct s5p_timer *const timer = s5p_get_base_timer();
113
114	/* reset time */
115	gd->arch.lastinc = readl(&timer->tcnto4);
116	gd->arch.tbl = 0;
117}
118
119/*
120 * This function is derived from PowerPC code (read timebase as long long).
121 * On ARM it just returns the timer value.
122 */
123unsigned long long get_ticks(void)
124{
125	return get_timer(0);
126}
127
128/*
129 * This function is derived from PowerPC code (timebase clock frequency).
130 * On ARM it returns the number of timer ticks per second.
131 */
132unsigned long get_tbclk(void)
133{
134	return CONFIG_SYS_HZ;
135}
136