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