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  * See file CREDITS for list of people who contributed to this
8  * project.
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License as
12  * published by the Free Software Foundation; either version 2 of
13  * the License, or (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
23  * MA 02111-1307 USA
24  */
25 
26 #include <common.h>
27 #include <div64.h>
28 #include <asm/io.h>
29 #include <asm/arch/pwm.h>
30 #include <asm/arch/clk.h>
31 #include <pwm.h>
32 
33 DECLARE_GLOBAL_DATA_PTR;
34 
35 unsigned long get_current_tick(void);
36 
37 /* macro to read the 16 bit timer */
38 static inline struct s5p_timer *s5p_get_base_timer(void)
39 {
40 	return (struct s5p_timer *)samsung_get_base_timer();
41 }
42 
43 /**
44  * Read the countdown timer.
45  *
46  * This operates at 1MHz and counts downwards. It will wrap about every
47  * hour (2^32 microseconds).
48  *
49  * @return current value of timer
50  */
51 static unsigned long timer_get_us_down(void)
52 {
53 	struct s5p_timer *const timer = s5p_get_base_timer();
54 
55 	return readl(&timer->tcnto4);
56 }
57 
58 int timer_init(void)
59 {
60 	/* PWM Timer 4 */
61 	pwm_init(4, MUX_DIV_4, 0);
62 	pwm_config(4, 100000, 100000);
63 	pwm_enable(4);
64 
65 	/* Use this as the current monotonic time in us */
66 	gd->arch.timer_reset_value = 0;
67 
68 	/* Use this as the last timer value we saw */
69 	gd->arch.lastinc = timer_get_us_down();
70 	reset_timer_masked();
71 
72 	return 0;
73 }
74 
75 /*
76  * timer without interrupts
77  */
78 unsigned long get_timer(unsigned long base)
79 {
80 	unsigned long long time_ms;
81 
82 	ulong now = timer_get_us_down();
83 
84 	/*
85 	 * Increment the time by the amount elapsed since the last read.
86 	 * The timer may have wrapped around, but it makes no difference to
87 	 * our arithmetic here.
88 	 */
89 	gd->arch.timer_reset_value += gd->arch.lastinc - now;
90 	gd->arch.lastinc = now;
91 
92 	/* Divide by 1000 to convert from us to ms */
93 	time_ms = gd->arch.timer_reset_value;
94 	do_div(time_ms, 1000);
95 	return time_ms - base;
96 }
97 
98 unsigned long timer_get_us(void)
99 {
100 	static unsigned long base_time_us;
101 
102 	struct s5p_timer *const timer =
103 		(struct s5p_timer *)samsung_get_base_timer();
104 	unsigned long now_downward_us = readl(&timer->tcnto4);
105 
106 	if (!base_time_us)
107 		base_time_us = now_downward_us;
108 
109 	/* Note that this timer counts downward. */
110 	return base_time_us - now_downward_us;
111 }
112 
113 /* delay x useconds */
114 void __udelay(unsigned long usec)
115 {
116 	unsigned long count_value;
117 
118 	count_value = timer_get_us_down();
119 	while ((int)(count_value - timer_get_us_down()) < (int)usec)
120 		;
121 }
122 
123 void reset_timer_masked(void)
124 {
125 	struct s5p_timer *const timer = s5p_get_base_timer();
126 
127 	/* reset time */
128 	gd->arch.lastinc = readl(&timer->tcnto4);
129 	gd->arch.tbl = 0;
130 }
131 
132 /*
133  * This function is derived from PowerPC code (read timebase as long long).
134  * On ARM it just returns the timer value.
135  */
136 unsigned long long get_ticks(void)
137 {
138 	return get_timer(0);
139 }
140 
141 /*
142  * This function is derived from PowerPC code (timebase clock frequency).
143  * On ARM it returns the number of timer ticks per second.
144  */
145 unsigned long get_tbclk(void)
146 {
147 	return CONFIG_SYS_HZ;
148 }
149