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1da177e4 LT |
1 | /* |
2 | * linux/arch/mips/dec/time.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992, 1995 Linus Torvalds | |
5 | * Copyright (C) 2000, 2003 Maciej W. Rozycki | |
6 | * | |
7 | * This file contains the time handling details for PC-style clocks as | |
8 | * found in some MIPS systems. | |
9 | * | |
10 | */ | |
11 | #include <linux/bcd.h> | |
1da177e4 | 12 | #include <linux/init.h> |
1da177e4 | 13 | #include <linux/mc146818rtc.h> |
1da177e4 | 14 | #include <linux/param.h> |
1da177e4 | 15 | |
6457d9fc YY |
16 | #include <asm/cpu-features.h> |
17 | #include <asm/ds1287.h> | |
18 | #include <asm/time.h> | |
1da177e4 LT |
19 | #include <asm/dec/interrupts.h> |
20 | #include <asm/dec/ioasic.h> | |
1da177e4 LT |
21 | #include <asm/dec/machtype.h> |
22 | ||
4b550488 | 23 | unsigned long read_persistent_clock(void) |
1da177e4 LT |
24 | { |
25 | unsigned int year, mon, day, hour, min, sec, real_year; | |
53c2df2f | 26 | unsigned long flags; |
1da177e4 | 27 | |
53c2df2f | 28 | spin_lock_irqsave(&rtc_lock, flags); |
ddcabb4f | 29 | |
1da177e4 LT |
30 | do { |
31 | sec = CMOS_READ(RTC_SECONDS); | |
32 | min = CMOS_READ(RTC_MINUTES); | |
33 | hour = CMOS_READ(RTC_HOURS); | |
34 | day = CMOS_READ(RTC_DAY_OF_MONTH); | |
35 | mon = CMOS_READ(RTC_MONTH); | |
36 | year = CMOS_READ(RTC_YEAR); | |
ddcabb4f MM |
37 | /* |
38 | * The PROM will reset the year to either '72 or '73. | |
39 | * Therefore we store the real year separately, in one | |
40 | * of unused BBU RAM locations. | |
41 | */ | |
42 | real_year = CMOS_READ(RTC_DEC_YEAR); | |
1da177e4 | 43 | } while (sec != CMOS_READ(RTC_SECONDS)); |
ddcabb4f MM |
44 | |
45 | spin_unlock_irqrestore(&rtc_lock, flags); | |
46 | ||
1da177e4 LT |
47 | if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { |
48 | sec = BCD2BIN(sec); | |
49 | min = BCD2BIN(min); | |
50 | hour = BCD2BIN(hour); | |
51 | day = BCD2BIN(day); | |
52 | mon = BCD2BIN(mon); | |
53 | year = BCD2BIN(year); | |
54 | } | |
ddcabb4f | 55 | |
1da177e4 LT |
56 | year += real_year - 72 + 2000; |
57 | ||
58 | return mktime(year, mon, day, hour, min, sec); | |
59 | } | |
60 | ||
61 | /* | |
4b550488 | 62 | * In order to set the CMOS clock precisely, rtc_mips_set_mmss has to |
1da177e4 LT |
63 | * be called 500 ms after the second nowtime has started, because when |
64 | * nowtime is written into the registers of the CMOS clock, it will | |
65 | * jump to the next second precisely 500 ms later. Check the Dallas | |
66 | * DS1287 data sheet for details. | |
67 | */ | |
4b550488 | 68 | int rtc_mips_set_mmss(unsigned long nowtime) |
1da177e4 LT |
69 | { |
70 | int retval = 0; | |
71 | int real_seconds, real_minutes, cmos_minutes; | |
72 | unsigned char save_control, save_freq_select; | |
73 | ||
53c2df2f AN |
74 | /* irq are locally disabled here */ |
75 | spin_lock(&rtc_lock); | |
1da177e4 LT |
76 | /* tell the clock it's being set */ |
77 | save_control = CMOS_READ(RTC_CONTROL); | |
78 | CMOS_WRITE((save_control | RTC_SET), RTC_CONTROL); | |
79 | ||
80 | /* stop and reset prescaler */ | |
81 | save_freq_select = CMOS_READ(RTC_FREQ_SELECT); | |
82 | CMOS_WRITE((save_freq_select | RTC_DIV_RESET2), RTC_FREQ_SELECT); | |
83 | ||
84 | cmos_minutes = CMOS_READ(RTC_MINUTES); | |
85 | if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) | |
86 | cmos_minutes = BCD2BIN(cmos_minutes); | |
87 | ||
88 | /* | |
89 | * since we're only adjusting minutes and seconds, | |
90 | * don't interfere with hour overflow. This avoids | |
91 | * messing with unknown time zones but requires your | |
92 | * RTC not to be off by more than 15 minutes | |
93 | */ | |
94 | real_seconds = nowtime % 60; | |
95 | real_minutes = nowtime / 60; | |
96 | if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1) | |
97 | real_minutes += 30; /* correct for half hour time zone */ | |
98 | real_minutes %= 60; | |
99 | ||
100 | if (abs(real_minutes - cmos_minutes) < 30) { | |
101 | if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { | |
102 | real_seconds = BIN2BCD(real_seconds); | |
103 | real_minutes = BIN2BCD(real_minutes); | |
104 | } | |
105 | CMOS_WRITE(real_seconds, RTC_SECONDS); | |
106 | CMOS_WRITE(real_minutes, RTC_MINUTES); | |
107 | } else { | |
108 | printk(KERN_WARNING | |
109 | "set_rtc_mmss: can't update from %d to %d\n", | |
110 | cmos_minutes, real_minutes); | |
111 | retval = -1; | |
112 | } | |
113 | ||
114 | /* The following flags have to be released exactly in this order, | |
115 | * otherwise the DS1287 will not reset the oscillator and will not | |
116 | * update precisely 500 ms later. You won't find this mentioned | |
117 | * in the Dallas Semiconductor data sheets, but who believes data | |
118 | * sheets anyway ... -- Markus Kuhn | |
119 | */ | |
120 | CMOS_WRITE(save_control, RTC_CONTROL); | |
121 | CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT); | |
53c2df2f | 122 | spin_unlock(&rtc_lock); |
1da177e4 LT |
123 | |
124 | return retval; | |
125 | } | |
126 | ||
6457d9fc | 127 | void __init plat_time_init(void) |
1da177e4 | 128 | { |
6457d9fc YY |
129 | u32 start, end; |
130 | int i = HZ / 10; | |
1da177e4 | 131 | |
6457d9fc YY |
132 | /* Set up the rate of periodic DS1287 interrupts. */ |
133 | ds1287_set_base_clock(HZ); | |
1da177e4 | 134 | |
6457d9fc YY |
135 | if (cpu_has_counter) { |
136 | while (!ds1287_timer_state()) | |
137 | ; | |
1da177e4 | 138 | |
6457d9fc | 139 | start = read_c0_count(); |
1da177e4 | 140 | |
6457d9fc YY |
141 | while (i--) |
142 | while (!ds1287_timer_state()) | |
143 | ; | |
144 | ||
145 | end = read_c0_count(); | |
1da177e4 | 146 | |
6457d9fc YY |
147 | mips_hpt_frequency = (end - start) * 10; |
148 | printk(KERN_INFO "MIPS counter frequency %dHz\n", | |
149 | mips_hpt_frequency); | |
150 | } else if (IOASIC) | |
1da177e4 | 151 | /* For pre-R4k systems we use the I/O ASIC's counter. */ |
4247417d | 152 | dec_ioasic_clocksource_init(); |
1da177e4 | 153 | |
6457d9fc | 154 | ds1287_clockevent_init(dec_interrupt[DEC_IRQ_RTC]); |
1da177e4 | 155 | } |