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 
23 DECLARE_GLOBAL_DATA_PTR;
24 
25 unsigned long get_current_tick(void);
26 static void reset_timer_masked(void);
27 
28 /* macro to read the 16 bit timer */
s5p_get_base_timer(void)29 static 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  */
timer_get_us_down(void)42 static 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 
timer_init(void)49 int 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  */
get_timer(unsigned long base)69 unsigned 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 
timer_get_us(void)89 unsigned 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 */
__udelay(unsigned long usec)105 void __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 
reset_timer_masked(void)114 static 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  */
get_ticks(void)127 unsigned 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  */
get_tbclk(void)136 unsigned long get_tbclk(void)
137 {
138 	return CONFIG_SYS_HZ;
139 }
140