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 <asm/io.h>
28 #include <asm/arch/pwm.h>
29 #include <asm/arch/clk.h>
30 #include <pwm.h>
31 
32 DECLARE_GLOBAL_DATA_PTR;
33 
34 unsigned long get_current_tick(void);
35 
36 /* macro to read the 16 bit timer */
37 static inline struct s5p_timer *s5p_get_base_timer(void)
38 {
39 	return (struct s5p_timer *)samsung_get_base_timer();
40 }
41 
42 /**
43  * Read the countdown timer.
44  *
45  * This operates at 1MHz and counts downwards. It will wrap about every
46  * hour (2^32 microseconds).
47  *
48  * @return current value of timer
49  */
50 static unsigned long timer_get_us_down(void)
51 {
52 	struct s5p_timer *const timer = s5p_get_base_timer();
53 
54 	return readl(&timer->tcnto4);
55 }
56 
57 int timer_init(void)
58 {
59 	/* PWM Timer 4 */
60 	pwm_init(4, MUX_DIV_4, 0);
61 	pwm_config(4, 100000, 100000);
62 	pwm_enable(4);
63 
64 	/* Use this as the current monotonic time in us */
65 	gd->arch.timer_reset_value = 0;
66 
67 	/* Use this as the last timer value we saw */
68 	gd->arch.lastinc = timer_get_us_down();
69 	reset_timer_masked();
70 
71 	return 0;
72 }
73 
74 /*
75  * timer without interrupts
76  */
77 unsigned long get_timer(unsigned long base)
78 {
79 	ulong now = timer_get_us_down();
80 
81 	/*
82 	 * Increment the time by the amount elapsed since the last read.
83 	 * The timer may have wrapped around, but it makes no difference to
84 	 * our arithmetic here.
85 	 */
86 	gd->arch.timer_reset_value += gd->arch.lastinc - now;
87 	gd->arch.lastinc = now;
88 
89 	/* Divide by 1000 to convert from us to ms */
90 	return gd->arch.timer_reset_value / 1000 - base;
91 }
92 
93 unsigned long timer_get_us(void)
94 {
95 	static unsigned long base_time_us;
96 
97 	struct s5p_timer *const timer =
98 		(struct s5p_timer *)samsung_get_base_timer();
99 	unsigned long now_downward_us = readl(&timer->tcnto4);
100 
101 	if (!base_time_us)
102 		base_time_us = now_downward_us;
103 
104 	/* Note that this timer counts downward. */
105 	return base_time_us - now_downward_us;
106 }
107 
108 /* delay x useconds */
109 void __udelay(unsigned long usec)
110 {
111 	unsigned long count_value;
112 
113 	count_value = timer_get_us_down();
114 	while ((int)(count_value - timer_get_us_down()) < (int)usec)
115 		;
116 }
117 
118 void reset_timer_masked(void)
119 {
120 	struct s5p_timer *const timer = s5p_get_base_timer();
121 
122 	/* reset time */
123 	gd->arch.lastinc = readl(&timer->tcnto4);
124 	gd->arch.tbl = 0;
125 }
126 
127 /*
128  * This function is derived from PowerPC code (read timebase as long long).
129  * On ARM it just returns the timer value.
130  */
131 unsigned long long get_ticks(void)
132 {
133 	return get_timer(0);
134 }
135 
136 /*
137  * This function is derived from PowerPC code (timebase clock frequency).
138  * On ARM it returns the number of timer ticks per second.
139  */
140 unsigned long get_tbclk(void)
141 {
142 	return CONFIG_SYS_HZ;
143 }
144