xref: /openbmc/u-boot/arch/sh/lib/time_sh2.c (revision d81b27a2)
1 /*
2  * Copyright (C) 2007,2008 Nobobuhiro Iwamatsu <iwamatsu@nigauri.org>
3  * Copyright (C) 2008 Renesas Solutions Corp.
4  *
5  * (C) Copyright 2003
6  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
7  *
8  * See file CREDITS for list of people who contributed to this
9  * project.
10  *
11  * This program is free software; you can redistribute it and/or
12  * modify it under the terms of the GNU General Public License as
13  * published by the Free Software Foundation; either version 2 of
14  * the License, or (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
24  * MA 02111-1307 USA
25  */
26 
27 #include <common.h>
28 #include <asm/io.h>
29 #include <asm/processor.h>
30 
31 #define CMT_CMCSR_INIT	0x0001	/* PCLK/32 */
32 #define CMT_CMCSR_CALIB 0x0000
33 #define CMT_MAX_COUNTER (0xFFFFFFFF)
34 #define CMT_TIMER_RESET (0xFFFF)
35 
36 static vu_long cmt0_timer;
37 
38 static void cmt_timer_start(unsigned int timer)
39 {
40 	writew(readw(CMSTR) | 0x01, CMSTR);
41 }
42 
43 static void cmt_timer_stop(unsigned int timer)
44 {
45 	writew(readw(CMSTR) & ~0x01, CMSTR);
46 }
47 
48 int timer_init(void)
49 {
50 	cmt0_timer = 0;
51 	/* Divide clock by 32 */
52 	readw(CMCSR_0);
53 	writew(CMT_CMCSR_INIT, CMCSR_0);
54 
55 	/* User Device 0 only */
56 	cmt_timer_stop(0);
57 	writew(CMT_TIMER_RESET, CMCOR_0);
58 	cmt_timer_start(0);
59 
60 	return 0;
61 }
62 
63 unsigned long long get_ticks(void)
64 {
65 	return cmt0_timer;
66 }
67 
68 static vu_long cmcnt = 0;
69 static unsigned long get_usec (void)
70 {
71 	ulong data = readw(CMCNT_0);
72 
73 	if (data >= cmcnt)
74 		cmcnt = data - cmcnt;
75 	else
76 		cmcnt = (CMT_TIMER_RESET - cmcnt) + data;
77 
78 	if ((cmt0_timer + cmcnt) > CMT_MAX_COUNTER)
79 		cmt0_timer = ((cmt0_timer + cmcnt) - CMT_MAX_COUNTER);
80 	else
81 		cmt0_timer += cmcnt;
82 
83 	cmcnt = data;
84 	return cmt0_timer;
85 }
86 
87 /* return msec */
88 ulong get_timer(ulong base)
89 {
90 	return (get_usec() / 1000) - base;
91 }
92 
93 void __udelay(unsigned long usec)
94 {
95 	unsigned long end = get_usec() + usec;
96 
97 	while (get_usec() < end)
98 		continue;
99 }
100 
101 unsigned long get_tbclk(void)
102 {
103 	return CONFIG_SYS_HZ;
104 }
105