1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
|
/*
* linux/include/asm-arm/arch-ebsa285/time.h
*
* Copyright (C) 1998 Russell King.
* Copyright (C) 1998 Phil Blundell
*
* CATS has a real-time clock, though the evaluation board doesn't.
*
* Changelog:
* 21-Mar-1998 RMK Created
* 27-Aug-1998 PJB CATS support
* 28-Dec-1998 APH Made leds optional
* 20-Jan-1999 RMK Started merge of EBSA285, CATS and NetWinder
* 16-Mar-1999 RMK More support for EBSA285-like machines with RTCs in
*/
#define RTC_PORT(x) (rtc_base+(x))
#define RTC_ALWAYS_BCD 0
#include <linux/timex.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/mc146818rtc.h>
#include <linux/bcd.h>
#include <asm/hardware.h>
#include <asm/io.h>
#include <asm/mach/time.h>
#include "common.h"
static int rtc_base;
static unsigned long __init get_isa_cmos_time(void)
{
unsigned int year, mon, day, hour, min, sec;
int i;
// check to see if the RTC makes sense.....
if ((CMOS_READ(RTC_VALID) & RTC_VRT) == 0)
return mktime(1970, 1, 1, 0, 0, 0);
/* The Linux interpretation of the CMOS clock register contents:
* When the Update-In-Progress (UIP) flag goes from 1 to 0, the
* RTC registers show the second which has precisely just started.
* Let's hope other operating systems interpret the RTC the same way.
*/
/* read RTC exactly on falling edge of update flag */
for (i = 0 ; i < 1000000 ; i++) /* may take up to 1 second... */
if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)
break;
for (i = 0 ; i < 1000000 ; i++) /* must try at least 2.228 ms */
if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
break;
do { /* Isn't this overkill ? UIP above should guarantee consistency */
sec = CMOS_READ(RTC_SECONDS);
min = CMOS_READ(RTC_MINUTES);
hour = CMOS_READ(RTC_HOURS);
day = CMOS_READ(RTC_DAY_OF_MONTH);
mon = CMOS_READ(RTC_MONTH);
year = CMOS_READ(RTC_YEAR);
} while (sec != CMOS_READ(RTC_SECONDS));
if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
BCD_TO_BIN(sec);
BCD_TO_BIN(min);
BCD_TO_BIN(hour);
BCD_TO_BIN(day);
BCD_TO_BIN(mon);
BCD_TO_BIN(year);
}
if ((year += 1900) < 1970)
year += 100;
return mktime(year, mon, day, hour, min, sec);
}
static int set_isa_cmos_time(void)
{
int retval = 0;
int real_seconds, real_minutes, cmos_minutes;
unsigned char save_control, save_freq_select;
unsigned long nowtime = xtime.tv_sec;
save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */
CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */
CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
cmos_minutes = CMOS_READ(RTC_MINUTES);
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
BCD_TO_BIN(cmos_minutes);
/*
* since we're only adjusting minutes and seconds,
* don't interfere with hour overflow. This avoids
* messing with unknown time zones but requires your
* RTC not to be off by more than 15 minutes
*/
real_seconds = nowtime % 60;
real_minutes = nowtime / 60;
if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
real_minutes += 30; /* correct for half hour time zone */
real_minutes %= 60;
if (abs(real_minutes - cmos_minutes) < 30) {
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
BIN_TO_BCD(real_seconds);
BIN_TO_BCD(real_minutes);
}
CMOS_WRITE(real_seconds,RTC_SECONDS);
CMOS_WRITE(real_minutes,RTC_MINUTES);
} else
retval = -1;
/* The following flags have to be released exactly in this order,
* otherwise the DS12887 (popular MC146818A clone with integrated
* battery and quartz) will not reset the oscillator and will not
* update precisely 500 ms later. You won't find this mentioned in
* the Dallas Semiconductor data sheets, but who believes data
* sheets anyway ... -- Markus Kuhn
*/
CMOS_WRITE(save_control, RTC_CONTROL);
CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
return retval;
}
void __init isa_rtc_init(void)
{
if (machine_is_co285() ||
machine_is_personal_server())
/*
* Add-in 21285s shouldn't access the RTC
*/
rtc_base = 0;
else
rtc_base = 0x70;
if (rtc_base) {
int reg_d, reg_b;
/*
* Probe for the RTC.
*/
reg_d = CMOS_READ(RTC_REG_D);
/*
* make sure the divider is set
*/
CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_REG_A);
/*
* Set control reg B
* (24 hour mode, update enabled)
*/
reg_b = CMOS_READ(RTC_REG_B) & 0x7f;
reg_b |= 2;
CMOS_WRITE(reg_b, RTC_REG_B);
if ((CMOS_READ(RTC_REG_A) & 0x7f) == RTC_REF_CLCK_32KHZ &&
CMOS_READ(RTC_REG_B) == reg_b) {
struct timespec tv;
/*
* We have a RTC. Check the battery
*/
if ((reg_d & 0x80) == 0)
printk(KERN_WARNING "RTC: *** warning: CMOS battery bad\n");
tv.tv_nsec = 0;
tv.tv_sec = get_isa_cmos_time();
do_settimeofday(&tv);
set_rtc = set_isa_cmos_time;
} else
rtc_base = 0;
}
}
|
