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 /* macro to read the 16 bit timer */
35 static inline struct s5p_timer *s5p_get_base_timer(void)
36 {
37 	return (struct s5p_timer *)samsung_get_base_timer();
38 }
39 
40 int timer_init(void)
41 {
42 	/* PWM Timer 4 */
43 	pwm_init(4, MUX_DIV_2, 0);
44 	pwm_config(4, 0, 0);
45 	pwm_enable(4);
46 
47 	return 0;
48 }
49 
50 /*
51  * timer without interrupts
52  */
53 unsigned long get_timer(unsigned long base)
54 {
55 	return get_timer_masked() - base;
56 }
57 
58 /* delay x useconds */
59 void __udelay(unsigned long usec)
60 {
61 	struct s5p_timer *const timer = s5p_get_base_timer();
62 	unsigned long tmo, tmp, count_value;
63 
64 	count_value = readl(&timer->tcntb4);
65 
66 	if (usec >= 1000) {
67 		/*
68 		 * if "big" number, spread normalization
69 		 * to seconds
70 		 * 1. start to normalize for usec to ticks per sec
71 		 * 2. find number of "ticks" to wait to achieve target
72 		 * 3. finish normalize.
73 		 */
74 		tmo = usec / 1000;
75 		tmo *= (CONFIG_SYS_HZ * count_value / 10);
76 		tmo /= 1000;
77 	} else {
78 		/* else small number, don't kill it prior to HZ multiply */
79 		tmo = usec * CONFIG_SYS_HZ * count_value / 10;
80 		tmo /= (1000 * 1000);
81 	}
82 
83 	/* get current timestamp */
84 	tmp = get_timer(0);
85 
86 	/* if setting this fordward will roll time stamp */
87 	/* reset "advancing" timestamp to 0, set lastinc value */
88 	/* else, set advancing stamp wake up time */
89 	if ((tmo + tmp + 1) < tmp)
90 		reset_timer_masked();
91 	else
92 		tmo += tmp;
93 
94 	/* loop till event */
95 	while (get_timer_masked() < tmo)
96 		;	/* nop */
97 }
98 
99 void reset_timer_masked(void)
100 {
101 	struct s5p_timer *const timer = s5p_get_base_timer();
102 
103 	/* reset time */
104 	gd->lastinc = readl(&timer->tcnto4);
105 	gd->tbl = 0;
106 }
107 
108 unsigned long get_timer_masked(void)
109 {
110 	struct s5p_timer *const timer = s5p_get_base_timer();
111 	unsigned long now = readl(&timer->tcnto4);
112 	unsigned long count_value = readl(&timer->tcntb4);
113 
114 	if (gd->lastinc >= now)
115 		gd->tbl += gd->lastinc - now;
116 	else
117 		gd->tbl += gd->lastinc + count_value - now;
118 
119 	gd->lastinc = now;
120 
121 	return gd->tbl;
122 }
123 
124 /*
125  * This function is derived from PowerPC code (read timebase as long long).
126  * On ARM it just returns the timer value.
127  */
128 unsigned long long get_ticks(void)
129 {
130 	return get_timer(0);
131 }
132 
133 /*
134  * This function is derived from PowerPC code (timebase clock frequency).
135  * On ARM it returns the number of timer ticks per second.
136  */
137 unsigned long get_tbclk(void)
138 {
139 	return CONFIG_SYS_HZ;
140 }
141