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 int timer_init(void)
43 {
44 	/* PWM Timer 4 */
45 	pwm_init(4, MUX_DIV_2, 0);
46 	pwm_config(4, 0, 0);
47 	pwm_enable(4);
48 
49 	reset_timer_masked();
50 
51 	return 0;
52 }
53 
54 /*
55  * timer without interrupts
56  */
57 unsigned long get_timer(unsigned long base)
58 {
59 	return get_timer_masked() - base;
60 }
61 
62 /* delay x useconds */
63 void __udelay(unsigned long usec)
64 {
65 	struct s5p_timer *const timer = s5p_get_base_timer();
66 	unsigned long tmo, tmp, count_value;
67 
68 	count_value = readl(&timer->tcntb4);
69 
70 	if (usec >= 1000) {
71 		/*
72 		 * if "big" number, spread normalization
73 		 * to seconds
74 		 * 1. start to normalize for usec to ticks per sec
75 		 * 2. find number of "ticks" to wait to achieve target
76 		 * 3. finish normalize.
77 		 */
78 		tmo = usec / 1000;
79 		tmo *= (CONFIG_SYS_HZ * count_value);
80 		tmo /= 1000;
81 	} else {
82 		/* else small number, don't kill it prior to HZ multiply */
83 		tmo = usec * CONFIG_SYS_HZ * count_value;
84 		tmo /= (1000 * 1000);
85 	}
86 
87 	/* get current timestamp */
88 	tmp = get_current_tick();
89 
90 	/* if setting this fordward will roll time stamp */
91 	/* reset "advancing" timestamp to 0, set lastinc value */
92 	/* else, set advancing stamp wake up time */
93 	if ((tmo + tmp + 1) < tmp)
94 		reset_timer_masked();
95 	else
96 		tmo += tmp;
97 
98 	/* loop till event */
99 	while (get_current_tick() < tmo)
100 		;	/* nop */
101 }
102 
103 void reset_timer_masked(void)
104 {
105 	struct s5p_timer *const timer = s5p_get_base_timer();
106 
107 	/* reset time */
108 	gd->lastinc = readl(&timer->tcnto4);
109 	gd->tbl = 0;
110 }
111 
112 unsigned long get_timer_masked(void)
113 {
114 	struct s5p_timer *const timer = s5p_get_base_timer();
115 	unsigned long count_value = readl(&timer->tcntb4);
116 
117 	return get_current_tick() / count_value;
118 }
119 
120 unsigned long get_current_tick(void)
121 {
122 	struct s5p_timer *const timer = s5p_get_base_timer();
123 	unsigned long now = readl(&timer->tcnto4);
124 	unsigned long count_value = readl(&timer->tcntb4);
125 
126 	if (gd->lastinc >= now)
127 		gd->tbl += gd->lastinc - now;
128 	else
129 		gd->tbl += gd->lastinc + count_value - now;
130 
131 	gd->lastinc = now;
132 
133 	return gd->tbl;
134 }
135 
136 /*
137  * This function is derived from PowerPC code (read timebase as long long).
138  * On ARM it just returns the timer value.
139  */
140 unsigned long long get_ticks(void)
141 {
142 	return get_timer(0);
143 }
144 
145 /*
146  * This function is derived from PowerPC code (timebase clock frequency).
147  * On ARM it returns the number of timer ticks per second.
148  */
149 unsigned long get_tbclk(void)
150 {
151 	return CONFIG_SYS_HZ;
152 }
153