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time.c
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1 /*
2  * Copyright (C) 1991, 1992, 1995 Linus Torvalds
3  *
4  * Adapted for PowerPC (PReP) by Gary Thomas
5  * Modified by Cort Dougan ([email protected]).
6  * Copied and modified from arch/i386/kernel/time.c
7  *
8  */
9 #include <linux/errno.h>
10 #include <linux/sched.h>
11 #include <linux/kernel.h>
12 #include <linux/param.h>
13 #include <linux/string.h>
14 #include <linux/mm.h>
15 #include <linux/interrupt.h>
16 #include <linux/time.h>
17 #include <linux/timex.h>
18 #include <linux/kernel_stat.h>
19 #include <linux/mc146818rtc.h>
20 #include <linux/init.h>
21 #include <linux/bcd.h>
22 #include <linux/ioport.h>
23 
24 #include <asm/io.h>
25 #include <asm/nvram.h>
26 #include <asm/prom.h>
27 #include <asm/sections.h>
28 #include <asm/time.h>
29 
30 extern spinlock_t rtc_lock;
31 
32 #define NVRAM_AS0 0x74
33 #define NVRAM_AS1 0x75
34 #define NVRAM_DATA 0x77
35 
36 static int nvram_as1 = NVRAM_AS1;
37 static int nvram_as0 = NVRAM_AS0;
38 static int nvram_data = NVRAM_DATA;
39 
40 long __init chrp_time_init(void)
41 {
42  struct device_node *rtcs;
43  struct resource r;
44  int base;
45 
46  rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00");
47  if (rtcs == NULL)
48  rtcs = of_find_compatible_node(NULL, "rtc", "ds1385-rtc");
49  if (rtcs == NULL)
50  return 0;
51  if (of_address_to_resource(rtcs, 0, &r)) {
52  of_node_put(rtcs);
53  return 0;
54  }
55  of_node_put(rtcs);
56 
57  base = r.start;
58  nvram_as1 = 0;
59  nvram_as0 = base;
60  nvram_data = base + 1;
61 
62  return 0;
63 }
64 
65 int chrp_cmos_clock_read(int addr)
66 {
67  if (nvram_as1 != 0)
68  outb(addr>>8, nvram_as1);
69  outb(addr, nvram_as0);
70  return (inb(nvram_data));
71 }
72 
73 void chrp_cmos_clock_write(unsigned long val, int addr)
74 {
75  if (nvram_as1 != 0)
76  outb(addr>>8, nvram_as1);
77  outb(addr, nvram_as0);
78  outb(val, nvram_data);
79  return;
80 }
81 
82 /*
83  * Set the hardware clock. -- Cort
84  */
85 int chrp_set_rtc_time(struct rtc_time *tmarg)
86 {
87  unsigned char save_control, save_freq_select;
88  struct rtc_time tm = *tmarg;
89 
90  spin_lock(&rtc_lock);
91 
92  save_control = chrp_cmos_clock_read(RTC_CONTROL); /* tell the clock it's being set */
93 
94  chrp_cmos_clock_write((save_control|RTC_SET), RTC_CONTROL);
95 
96  save_freq_select = chrp_cmos_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
97 
98  chrp_cmos_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
99 
100  if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
101  tm.tm_sec = bin2bcd(tm.tm_sec);
102  tm.tm_min = bin2bcd(tm.tm_min);
103  tm.tm_hour = bin2bcd(tm.tm_hour);
104  tm.tm_mon = bin2bcd(tm.tm_mon);
105  tm.tm_mday = bin2bcd(tm.tm_mday);
106  tm.tm_year = bin2bcd(tm.tm_year);
107  }
108  chrp_cmos_clock_write(tm.tm_sec,RTC_SECONDS);
109  chrp_cmos_clock_write(tm.tm_min,RTC_MINUTES);
110  chrp_cmos_clock_write(tm.tm_hour,RTC_HOURS);
111  chrp_cmos_clock_write(tm.tm_mon,RTC_MONTH);
112  chrp_cmos_clock_write(tm.tm_mday,RTC_DAY_OF_MONTH);
113  chrp_cmos_clock_write(tm.tm_year,RTC_YEAR);
114 
115  /* The following flags have to be released exactly in this order,
116  * otherwise the DS12887 (popular MC146818A clone with integrated
117  * battery and quartz) will not reset the oscillator and will not
118  * update precisely 500 ms later. You won't find this mentioned in
119  * the Dallas Semiconductor data sheets, but who believes data
120  * sheets anyway ... -- Markus Kuhn
121  */
122  chrp_cmos_clock_write(save_control, RTC_CONTROL);
123  chrp_cmos_clock_write(save_freq_select, RTC_FREQ_SELECT);
124 
125  spin_unlock(&rtc_lock);
126  return 0;
127 }
128 
129 void chrp_get_rtc_time(struct rtc_time *tm)
130 {
131  unsigned int year, mon, day, hour, min, sec;
132 
133  do {
134  sec = chrp_cmos_clock_read(RTC_SECONDS);
135  min = chrp_cmos_clock_read(RTC_MINUTES);
136  hour = chrp_cmos_clock_read(RTC_HOURS);
137  day = chrp_cmos_clock_read(RTC_DAY_OF_MONTH);
138  mon = chrp_cmos_clock_read(RTC_MONTH);
139  year = chrp_cmos_clock_read(RTC_YEAR);
140  } while (sec != chrp_cmos_clock_read(RTC_SECONDS));
141 
142  if (!(chrp_cmos_clock_read(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
143  sec = bcd2bin(sec);
144  min = bcd2bin(min);
145  hour = bcd2bin(hour);
146  day = bcd2bin(day);
147  mon = bcd2bin(mon);
148  year = bcd2bin(year);
149  }
150  if (year < 70)
151  year += 100;
152  tm->tm_sec = sec;
153  tm->tm_min = min;
154  tm->tm_hour = hour;
155  tm->tm_mday = day;
156  tm->tm_mon = mon;
157  tm->tm_year = year;
158 }
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