File: /usr/src/linux/arch/sh/kernel/rtc.c
1 /*
2 * linux/arch/sh/kernel/rtc.c -- SH3 / SH4 on-chip RTC support
3 *
4 * Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
5 * Copyright (C) 1999 Tetsuya Okada & Niibe Yutaka
6 */
7
8 #include <linux/init.h>
9 #include <linux/kernel.h>
10 #include <linux/sched.h>
11 #include <linux/time.h>
12
13 #include <asm/io.h>
14 #include <asm/rtc.h>
15
16 #ifndef BCD_TO_BIN
17 #define BCD_TO_BIN(val) ((val)=((val)&15) + ((val)>>4)*10)
18 #endif
19
20 #ifndef BIN_TO_BCD
21 #define BIN_TO_BCD(val) ((val)=(((val)/10)<<4) + (val)%10)
22 #endif
23
24 void sh_rtc_gettimeofday(struct timeval *tv)
25 {
26 unsigned int sec128, sec, min, hr, wk, day, mon, yr, yr100;
27
28 again:
29 do {
30 ctrl_outb(0, RCR1); /* Clear CF-bit */
31 sec128 = ctrl_inb(R64CNT);
32 sec = ctrl_inb(RSECCNT);
33 min = ctrl_inb(RMINCNT);
34 hr = ctrl_inb(RHRCNT);
35 wk = ctrl_inb(RWKCNT);
36 day = ctrl_inb(RDAYCNT);
37 mon = ctrl_inb(RMONCNT);
38 #if defined(__SH4__)
39 yr = ctrl_inw(RYRCNT);
40 yr100 = (yr >> 8);
41 yr &= 0xff;
42 #else
43 yr = ctrl_inb(RYRCNT);
44 yr100 = (yr == 0x99) ? 0x19 : 0x20;
45 #endif
46 } while ((ctrl_inb(RCR1) & RCR1_CF) != 0);
47
48 #if RTC_BIT_INVERTED != 0
49 /* Work around to avoid reading correct value. */
50 if (sec128 == RTC_BIT_INVERTED) {
51 schedule_timeout(1);
52 goto again;
53 }
54 #endif
55
56 BCD_TO_BIN(yr100);
57 BCD_TO_BIN(yr);
58 BCD_TO_BIN(mon);
59 BCD_TO_BIN(day);
60 BCD_TO_BIN(hr);
61 BCD_TO_BIN(min);
62 BCD_TO_BIN(sec);
63
64 if (yr > 99 || mon < 1 || mon > 12 || day > 31 || day < 1 ||
65 hr > 23 || min > 59 || sec > 59) {
66 printk(KERN_ERR
67 "SH RTC: invalid value, resetting to 1 Jan 2000\n");
68 ctrl_outb(RCR2_RESET, RCR2); /* Reset & Stop */
69 ctrl_outb(0, RSECCNT);
70 ctrl_outb(0, RMINCNT);
71 ctrl_outb(0, RHRCNT);
72 ctrl_outb(6, RWKCNT);
73 ctrl_outb(1, RDAYCNT);
74 ctrl_outb(1, RMONCNT);
75 #if defined(__SH4__)
76 ctrl_outw(0x2000, RYRCNT);
77 #else
78 ctrl_outb(0, RYRCNT);
79 #endif
80 ctrl_outb(RCR2_RTCEN|RCR2_START, RCR2); /* Start */
81 goto again;
82 }
83
84 tv->tv_sec = mktime(yr100 * 100 + yr, mon, day, hr, min, sec);
85 tv->tv_usec = ((sec128 ^ RTC_BIT_INVERTED) * 1000000) / 128;
86 }
87
88 static int set_rtc_time(unsigned long nowtime)
89 {
90 int retval = 0;
91 int real_seconds, real_minutes, cmos_minutes;
92
93 ctrl_outb(RCR2_RESET, RCR2); /* Reset pre-scaler & stop RTC */
94
95 cmos_minutes = ctrl_inb(RMINCNT);
96 BCD_TO_BIN(cmos_minutes);
97
98 /*
99 * since we're only adjusting minutes and seconds,
100 * don't interfere with hour overflow. This avoids
101 * messing with unknown time zones but requires your
102 * RTC not to be off by more than 15 minutes
103 */
104 real_seconds = nowtime % 60;
105 real_minutes = nowtime / 60;
106 if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
107 real_minutes += 30; /* correct for half hour time zone */
108 real_minutes %= 60;
109
110 if (abs(real_minutes - cmos_minutes) < 30) {
111 BIN_TO_BCD(real_seconds);
112 BIN_TO_BCD(real_minutes);
113 ctrl_outb(real_seconds, RSECCNT);
114 ctrl_outb(real_minutes, RMINCNT);
115 } else {
116 printk(KERN_WARNING
117 "set_rtc_time: can't update from %d to %d\n",
118 cmos_minutes, real_minutes);
119 retval = -1;
120 }
121
122 ctrl_outb(RCR2_RTCEN|RCR2_START, RCR2); /* Start RTC */
123
124 return retval;
125 }
126
127 int sh_rtc_settimeofday(const struct timeval *tv)
128 {
129 #if RTC_BIT_INVERTED != 0
130 /* This is not accurate, but better than nothing. */
131 schedule_timeout(HZ/2);
132 #endif
133 return set_rtc_time(tv->tv_sec);
134 }
135