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 <asm/io.h>
12 #include <asm/arch/pwm.h>
13 #include <asm/arch/clk.h>
14 
15 /* Use the old PWM interface for now */
16 #undef CONFIG_DM_PWM
17 #include <pwm.h>
18 
19 DECLARE_GLOBAL_DATA_PTR;
20 
21 unsigned long get_current_tick(void);
22 static void reset_timer_masked(void);
23 
24 /* macro to read the 16 bit timer */
25 static 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  */
38 static 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 
45 int timer_init(void)
46 {
47 	/* PWM Timer 4 */
48 	pwm_init(4, MUX_DIV_4, 0);
49 	pwm_config(4, 100000, 100000);
50 	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  */
65 unsigned 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 
85 unsigned long __attribute__((no_instrument_function)) 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 */
101 void __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 
110 static 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  */
123 unsigned 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  */
132 unsigned long get_tbclk(void)
133 {
134 	return CONFIG_SYS_HZ;
135 }
136