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
181
182
183
184
185
186
187
188
189
190
191
|
/*
* arch/ppc/platforms/chrp_time.c
*
* Copyright (C) 1991, 1992, 1995 Linus Torvalds
*
* Adapted for PowerPC (PReP) by Gary Thomas
* Modified by Cort Dougan (cort@cs.nmt.edu).
* Copied and modified from arch/i386/kernel/time.c
*
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/kernel_stat.h>
#include <linux/mc146818rtc.h>
#include <linux/init.h>
#include <linux/bcd.h>
#include <asm/io.h>
#include <asm/nvram.h>
#include <asm/prom.h>
#include <asm/sections.h>
#include <asm/time.h>
extern spinlock_t rtc_lock;
static int nvram_as1 = NVRAM_AS1;
static int nvram_as0 = NVRAM_AS0;
static int nvram_data = NVRAM_DATA;
long __init chrp_time_init(void)
{
struct device_node *rtcs;
int base;
rtcs = find_compatible_devices("rtc", "pnpPNP,b00");
if (rtcs == NULL)
rtcs = find_compatible_devices("rtc", "ds1385-rtc");
if (rtcs == NULL || rtcs->addrs == NULL)
return 0;
base = rtcs->addrs[0].address;
nvram_as1 = 0;
nvram_as0 = base;
nvram_data = base + 1;
return 0;
}
int chrp_cmos_clock_read(int addr)
{
if (nvram_as1 != 0)
outb(addr>>8, nvram_as1);
outb(addr, nvram_as0);
return (inb(nvram_data));
}
void chrp_cmos_clock_write(unsigned long val, int addr)
{
if (nvram_as1 != 0)
outb(addr>>8, nvram_as1);
outb(addr, nvram_as0);
outb(val, nvram_data);
return;
}
/*
* Set the hardware clock. -- Cort
*/
int chrp_set_rtc_time(unsigned long nowtime)
{
unsigned char save_control, save_freq_select;
struct rtc_time tm;
spin_lock(&rtc_lock);
to_tm(nowtime, &tm);
save_control = chrp_cmos_clock_read(RTC_CONTROL); /* tell the clock it's being set */
chrp_cmos_clock_write((save_control|RTC_SET), RTC_CONTROL);
save_freq_select = chrp_cmos_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
chrp_cmos_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
tm.tm_year -= 1900;
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
BIN_TO_BCD(tm.tm_sec);
BIN_TO_BCD(tm.tm_min);
BIN_TO_BCD(tm.tm_hour);
BIN_TO_BCD(tm.tm_mon);
BIN_TO_BCD(tm.tm_mday);
BIN_TO_BCD(tm.tm_year);
}
chrp_cmos_clock_write(tm.tm_sec,RTC_SECONDS);
chrp_cmos_clock_write(tm.tm_min,RTC_MINUTES);
chrp_cmos_clock_write(tm.tm_hour,RTC_HOURS);
chrp_cmos_clock_write(tm.tm_mon,RTC_MONTH);
chrp_cmos_clock_write(tm.tm_mday,RTC_DAY_OF_MONTH);
chrp_cmos_clock_write(tm.tm_year,RTC_YEAR);
/* 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
*/
chrp_cmos_clock_write(save_control, RTC_CONTROL);
chrp_cmos_clock_write(save_freq_select, RTC_FREQ_SELECT);
spin_unlock(&rtc_lock);
return 0;
}
unsigned long chrp_get_rtc_time(void)
{
unsigned int year, mon, day, hour, min, sec;
int uip, i;
/* 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.
*/
/* Since the UIP flag is set for about 2.2 ms and the clock
* is typically written with a precision of 1 jiffy, trying
* to obtain a precision better than a few milliseconds is
* an illusion. Only consistency is interesting, this also
* allows to use the routine for /dev/rtc without a potential
* 1 second kernel busy loop triggered by any reader of /dev/rtc.
*/
for ( i = 0; i<1000000; i++) {
uip = chrp_cmos_clock_read(RTC_FREQ_SELECT);
sec = chrp_cmos_clock_read(RTC_SECONDS);
min = chrp_cmos_clock_read(RTC_MINUTES);
hour = chrp_cmos_clock_read(RTC_HOURS);
day = chrp_cmos_clock_read(RTC_DAY_OF_MONTH);
mon = chrp_cmos_clock_read(RTC_MONTH);
year = chrp_cmos_clock_read(RTC_YEAR);
uip |= chrp_cmos_clock_read(RTC_FREQ_SELECT);
if ((uip & RTC_UIP)==0) break;
}
if (!(chrp_cmos_clock_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);
}
void __init chrp_calibrate_decr(void)
{
struct device_node *cpu;
unsigned int freq, *fp;
if (via_calibrate_decr())
return;
/*
* The cpu node should have a timebase-frequency property
* to tell us the rate at which the decrementer counts.
*/
freq = 16666000; /* hardcoded default */
cpu = find_type_devices("cpu");
if (cpu != 0) {
fp = (unsigned int *)
get_property(cpu, "timebase-frequency", NULL);
if (fp != 0)
freq = *fp;
}
printk("time_init: decrementer frequency = %u.%.6u MHz\n",
freq/1000000, freq%1000000);
tb_ticks_per_jiffy = freq / HZ;
tb_to_us = mulhwu_scale_factor(freq, 1000000);
}
|
