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 void reset_timer(void)
54 {
55 	reset_timer_masked();
56 }
57 
58 unsigned long get_timer(unsigned long base)
59 {
60 	return get_timer_masked() - base;
61 }
62 
63 void set_timer(unsigned long t)
64 {
65 	gd->tbl = t;
66 }
67 
68 /* delay x useconds */
69 void __udelay(unsigned long usec)
70 {
71 	struct s5p_timer *const timer = s5p_get_base_timer();
72 	unsigned long tmo, tmp, count_value;
73 
74 	count_value = readl(&timer->tcntb4);
75 
76 	if (usec >= 1000) {
77 		/*
78 		 * if "big" number, spread normalization
79 		 * to seconds
80 		 * 1. start to normalize for usec to ticks per sec
81 		 * 2. find number of "ticks" to wait to achieve target
82 		 * 3. finish normalize.
83 		 */
84 		tmo = usec / 1000;
85 		tmo *= (CONFIG_SYS_HZ * count_value / 10);
86 		tmo /= 1000;
87 	} else {
88 		/* else small number, don't kill it prior to HZ multiply */
89 		tmo = usec * CONFIG_SYS_HZ * count_value / 10;
90 		tmo /= (1000 * 1000);
91 	}
92 
93 	/* get current timestamp */
94 	tmp = get_timer(0);
95 
96 	/* if setting this fordward will roll time stamp */
97 	/* reset "advancing" timestamp to 0, set lastinc value */
98 	/* else, set advancing stamp wake up time */
99 	if ((tmo + tmp + 1) < tmp)
100 		reset_timer_masked();
101 	else
102 		tmo += tmp;
103 
104 	/* loop till event */
105 	while (get_timer_masked() < tmo)
106 		;	/* nop */
107 }
108 
109 void reset_timer_masked(void)
110 {
111 	struct s5p_timer *const timer = s5p_get_base_timer();
112 
113 	/* reset time */
114 	gd->lastinc = readl(&timer->tcnto4);
115 	gd->tbl = 0;
116 }
117 
118 unsigned long get_timer_masked(void)
119 {
120 	struct s5p_timer *const timer = s5p_get_base_timer();
121 	unsigned long now = readl(&timer->tcnto4);
122 	unsigned long count_value = readl(&timer->tcntb4);
123 
124 	if (gd->lastinc >= now)
125 		gd->tbl += gd->lastinc - now;
126 	else
127 		gd->tbl += gd->lastinc + count_value - now;
128 
129 	gd->lastinc = now;
130 
131 	return gd->tbl;
132 }
133 
134 /*
135  * This function is derived from PowerPC code (read timebase as long long).
136  * On ARM it just returns the timer value.
137  */
138 unsigned long long get_ticks(void)
139 {
140 	return get_timer(0);
141 }
142 
143 /*
144  * This function is derived from PowerPC code (timebase clock frequency).
145  * On ARM it returns the number of timer ticks per second.
146  */
147 unsigned long get_tbclk(void)
148 {
149 	return CONFIG_SYS_HZ;
150 }
151