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
sh_rtc_gettimeofday(struct timeval * tv)24 void sh_rtc_gettimeofday(struct timeval *tv)
25 {
26 unsigned int sec128, sec, min, hr, wk, day, mon, yr, yr100, badval;
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 incorrect value. */
50 if (sec128 == RTC_BIT_INVERTED) {
51 schedule_timeout(1);
52 goto again;
53 }
54 #endif
55
56 badval = ((yr & 15) > 9 || (mon & 15) > 9 || (day & 15) > 9 ||
57 (hr & 15) > 9 || (min & 15) > 9 || (sec & 15) > 9);
58
59 if (!badval) {
60 BCD_TO_BIN(yr100);
61 BCD_TO_BIN(yr);
62 BCD_TO_BIN(mon);
63 BCD_TO_BIN(day);
64 BCD_TO_BIN(hr);
65 BCD_TO_BIN(min);
66 BCD_TO_BIN(sec);
67 }
68
69 if (badval || yr > 99 || mon < 1 || mon > 12 || day > 31 || day < 1 ||
70 hr > 23 || min > 59 || sec > 59 || (yr100 != 19 && yr100 != 20)) {
71 printk(KERN_ERR
72 "SH RTC: invalid value, resetting to 1 Jan 2000\n");
73 ctrl_outb(RCR2_RESET, RCR2); /* Reset & Stop */
74 ctrl_outb(0, RSECCNT);
75 ctrl_outb(0, RMINCNT);
76 ctrl_outb(0, RHRCNT);
77 ctrl_outb(6, RWKCNT);
78 ctrl_outb(1, RDAYCNT);
79 ctrl_outb(1, RMONCNT);
80 #if defined(__SH4__)
81 ctrl_outw(0x2000, RYRCNT);
82 #else
83 ctrl_outb(0, RYRCNT);
84 #endif
85 ctrl_outb(RCR2_RTCEN|RCR2_START, RCR2); /* Start */
86 goto again;
87 }
88
89 #if RTC_BIT_INVERTED != 0
90 if ((sec128 & RTC_BIT_INVERTED))
91 sec--;
92 #endif
93
94 tv->tv_sec = mktime(yr100 * 100 + yr, mon, day, hr, min, sec);
95 tv->tv_usec = (sec128 * 1000000) / 128;
96 }
97
sh_rtc_settimeofday(const struct timeval * tv)98 int sh_rtc_settimeofday(const struct timeval *tv)
99 {
100 unsigned long nowtime = tv->tv_sec;
101 int retval = 0;
102 int real_seconds, real_minutes, cmos_minutes;
103
104 ctrl_outb(RCR2_RESET, RCR2); /* Reset pre-scaler & stop RTC */
105
106 cmos_minutes = ctrl_inb(RMINCNT);
107 BCD_TO_BIN(cmos_minutes);
108
109 /*
110 * since we're only adjusting minutes and seconds,
111 * don't interfere with hour overflow. This avoids
112 * messing with unknown time zones but requires your
113 * RTC not to be off by more than 15 minutes
114 */
115 real_seconds = nowtime % 60;
116 real_minutes = nowtime / 60;
117 if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
118 real_minutes += 30; /* correct for half hour time zone */
119 real_minutes %= 60;
120
121 if (abs(real_minutes - cmos_minutes) < 30) {
122 BIN_TO_BCD(real_seconds);
123 BIN_TO_BCD(real_minutes);
124 ctrl_outb(real_seconds, RSECCNT);
125 ctrl_outb(real_minutes, RMINCNT);
126 } else {
127 printk(KERN_WARNING
128 "set_rtc_time: can't update from %d to %d\n",
129 cmos_minutes, real_minutes);
130 retval = -1;
131 }
132
133 ctrl_outb(RCR2_RTCEN|RCR2_START, RCR2); /* Start RTC */
134
135 return retval;
136 }
137