xref: /openbmc/u-boot/arch/sh/lib/time.c (revision 1e52fea3)
1 /*
2  * (C) Copyright 2009
3  * Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
4  *
5  * (C) Copyright 2007-2010
6  * Nobobuhiro Iwamatsu <iwamatsu@nigauri.org>
7  *
8  * (C) Copyright 2003
9  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
10  *
11  * See file CREDITS for list of people who contributed to this
12  * project.
13  *
14  * This program is free software; you can redistribute it and/or
15  * modify it under the terms of the GNU General Public License as
16  * published by the Free Software Foundation; either version 2 of
17  * the License, or (at your option) any later version.
18  *
19  * This program is distributed in the hope that it will be useful,
20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22  * GNU General Public License for more details.
23  *
24  * You should have received a copy of the GNU General Public License
25  * along with this program; if not, write to the Free Software
26  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27  * MA 02111-1307 USA
28  */
29 
30 #include <common.h>
31 #include <div64.h>
32 #include <asm/processor.h>
33 #include <asm/clk.h>
34 #include <asm/io.h>
35 
36 #define TMU_MAX_COUNTER (~0UL)
37 
38 static ulong timer_freq;
39 static unsigned long last_tcnt;
40 static unsigned long long overflow_ticks;
41 
42 static inline unsigned long long tick_to_time(unsigned long long tick)
43 {
44 	tick *= CONFIG_SYS_HZ;
45 	do_div(tick, timer_freq);
46 
47 	return tick;
48 }
49 
50 static inline unsigned long long usec_to_tick(unsigned long long usec)
51 {
52 	usec *= timer_freq;
53 	do_div(usec, 1000000);
54 
55 	return usec;
56 }
57 
58 static void tmu_timer_start (unsigned int timer)
59 {
60 	if (timer > 2)
61 		return;
62 	writeb(readb(TSTR) | (1 << timer), TSTR);
63 }
64 
65 static void tmu_timer_stop (unsigned int timer)
66 {
67 	if (timer > 2)
68 		return;
69 	writeb(readb(TSTR) & ~(1 << timer), TSTR);
70 }
71 
72 int timer_init (void)
73 {
74 	/* Divide clock by CONFIG_SYS_TMU_CLK_DIV */
75 	u16 bit = 0;
76 
77 	switch (CONFIG_SYS_TMU_CLK_DIV) {
78 	case 1024:
79 		bit = 4;
80 		break;
81 	case 256:
82 		bit = 3;
83 		break;
84 	case 64:
85 		bit = 2;
86 		break;
87 	case 16:
88 		bit = 1;
89 		break;
90 	case 4:
91 	default:
92 		break;
93 	}
94 	writew(readw(TCR0) | bit, TCR0);
95 
96 	/* Calc clock rate */
97 	timer_freq = get_tmu0_clk_rate() >> ((bit + 1) * 2);
98 
99 	tmu_timer_stop(0);
100 	tmu_timer_start(0);
101 
102 	last_tcnt = 0;
103 	overflow_ticks = 0;
104 
105 	return 0;
106 }
107 
108 unsigned long long get_ticks (void)
109 {
110 	unsigned long tcnt = 0 - readl(TCNT0);
111 
112 	if (last_tcnt > tcnt) /* overflow */
113 		overflow_ticks++;
114 	last_tcnt = tcnt;
115 
116 	return (overflow_ticks << 32) | tcnt;
117 }
118 
119 void __udelay (unsigned long usec)
120 {
121 	unsigned long long tmp;
122 	ulong tmo;
123 
124 	tmo = usec_to_tick(usec);
125 	tmp = get_ticks() + tmo;	/* get current timestamp */
126 
127 	while (get_ticks() < tmp)	/* loop till event */
128 		 /*NOP*/;
129 }
130 
131 unsigned long get_timer (unsigned long base)
132 {
133 	/* return msec */
134 	return tick_to_time(get_ticks()) - base;
135 }
136 
137 unsigned long get_tbclk (void)
138 {
139 	return timer_freq;
140 }
141