xref: /openbmc/u-boot/drivers/rtc/mc146818.c (revision fd697ecf)
1 /*
2  * (C) Copyright 2001
3  * Denis Peter MPL AG Switzerland. d.peter@mpl.ch
4  *
5  * SPDX-License-Identifier:	GPL-2.0+
6  */
7 
8 /*
9  * Date & Time support for the MC146818 (PIXX4) RTC
10  */
11 
12 /*#define	DEBUG*/
13 
14 #include <common.h>
15 #include <command.h>
16 #include <rtc.h>
17 #include <version.h>
18 
19 #if defined(__I386__) || defined(CONFIG_MALTA)
20 #include <asm/io.h>
21 #define in8(p) inb(p)
22 #define out8(p, v) outb(v, p)
23 #endif
24 
25 #if defined(CONFIG_CMD_DATE)
26 
27 /* Set this to 1 to clear the CMOS RAM */
28 #define CLEAR_CMOS 0
29 
30 #define RTC_PORT_MC146818	CONFIG_SYS_ISA_IO_BASE_ADDRESS +  0x70
31 #define RTC_SECONDS		0x00
32 #define RTC_SECONDS_ALARM	0x01
33 #define RTC_MINUTES		0x02
34 #define RTC_MINUTES_ALARM	0x03
35 #define RTC_HOURS		0x04
36 #define RTC_HOURS_ALARM		0x05
37 #define RTC_DAY_OF_WEEK		0x06
38 #define RTC_DATE_OF_MONTH	0x07
39 #define RTC_MONTH		0x08
40 #define RTC_YEAR		0x09
41 #define RTC_CONFIG_A		0x0A
42 #define RTC_CONFIG_B		0x0B
43 #define RTC_CONFIG_C		0x0C
44 #define RTC_CONFIG_D		0x0D
45 #define RTC_REG_SIZE		0x80
46 
47 #define RTC_CONFIG_A_REF_CLCK_32KHZ	(1 << 5)
48 #define RTC_CONFIG_A_RATE_1024HZ	6
49 
50 #define RTC_CONFIG_B_24H		(1 << 1)
51 
52 #define RTC_CONFIG_D_VALID_RAM_AND_TIME	0x80
53 
54 /* ------------------------------------------------------------------------- */
55 
56 int rtc_get (struct rtc_time *tmp)
57 {
58 	uchar sec, min, hour, mday, wday, mon, year;
59   /* here check if rtc can be accessed */
60 	while ((rtc_read8(RTC_CONFIG_A) & 0x80) == 0x80);
61 	sec	= rtc_read8(RTC_SECONDS);
62 	min	= rtc_read8(RTC_MINUTES);
63 	hour	= rtc_read8(RTC_HOURS);
64 	mday	= rtc_read8(RTC_DATE_OF_MONTH);
65 	wday	= rtc_read8(RTC_DAY_OF_WEEK);
66 	mon	= rtc_read8(RTC_MONTH);
67 	year	= rtc_read8(RTC_YEAR);
68 #ifdef RTC_DEBUG
69 	printf ( "Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x "
70 		"hr: %02x min: %02x sec: %02x\n",
71 		year, mon, mday, wday,
72 		hour, min, sec );
73 	printf ( "Alarms: month: %02x hour: %02x min: %02x sec: %02x\n",
74 		rtc_read8(RTC_CONFIG_D) & 0x3F,
75 		rtc_read8(RTC_HOURS_ALARM),
76 		rtc_read8(RTC_MINUTES_ALARM),
77 		rtc_read8(RTC_SECONDS_ALARM));
78 #endif
79 	tmp->tm_sec  = bcd2bin (sec  & 0x7F);
80 	tmp->tm_min  = bcd2bin (min  & 0x7F);
81 	tmp->tm_hour = bcd2bin (hour & 0x3F);
82 	tmp->tm_mday = bcd2bin (mday & 0x3F);
83 	tmp->tm_mon  = bcd2bin (mon & 0x1F);
84 	tmp->tm_year = bcd2bin (year);
85 	tmp->tm_wday = bcd2bin (wday & 0x07);
86 	if(tmp->tm_year<70)
87 		tmp->tm_year+=2000;
88 	else
89 		tmp->tm_year+=1900;
90 	tmp->tm_yday = 0;
91 	tmp->tm_isdst= 0;
92 #ifdef RTC_DEBUG
93 	printf ( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
94 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
95 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
96 #endif
97 
98 	return 0;
99 }
100 
101 int rtc_set (struct rtc_time *tmp)
102 {
103 #ifdef RTC_DEBUG
104 	printf ( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
105 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
106 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
107 #endif
108 	rtc_write8(RTC_CONFIG_B, 0x82); /* disable the RTC to update the regs */
109 
110 	rtc_write8(RTC_YEAR, bin2bcd(tmp->tm_year % 100));
111 	rtc_write8(RTC_MONTH, bin2bcd(tmp->tm_mon));
112 	rtc_write8(RTC_DAY_OF_WEEK, bin2bcd(tmp->tm_wday));
113 	rtc_write8(RTC_DATE_OF_MONTH, bin2bcd(tmp->tm_mday));
114 	rtc_write8(RTC_HOURS, bin2bcd(tmp->tm_hour));
115 	rtc_write8(RTC_MINUTES, bin2bcd(tmp->tm_min));
116 	rtc_write8(RTC_SECONDS, bin2bcd(tmp->tm_sec));
117 	rtc_write8(RTC_CONFIG_B, 0x02); /* enable the RTC to update the regs */
118 
119 	return 0;
120 }
121 
122 void rtc_reset (void)
123 {
124 	rtc_write8(RTC_CONFIG_B, 0x82); /* disable the RTC to update the regs */
125 	rtc_write8(RTC_CONFIG_A, 0x20); /* Normal OP */
126 	rtc_write8(RTC_CONFIG_B, 0x00);
127 	rtc_write8(RTC_CONFIG_B, 0x00);
128 	rtc_write8(RTC_CONFIG_B, 0x02); /* enable the RTC to update the regs */
129 }
130 
131 /* ------------------------------------------------------------------------- */
132 
133 /*
134  * use direct memory access
135  */
136 int rtc_read8(int reg)
137 {
138 #ifdef CONFIG_SYS_RTC_REG_BASE_ADDR
139 	return in8(CONFIG_SYS_RTC_REG_BASE_ADDR + reg);
140 #else
141 	int ofs = 0;
142 
143 	if (reg >= 128) {
144 		ofs = 2;
145 		reg -= 128;
146 	}
147 	out8(RTC_PORT_MC146818 + ofs, reg);
148 
149 	return in8(RTC_PORT_MC146818 + ofs + 1);
150 #endif
151 }
152 
153 void rtc_write8(int reg, uchar val)
154 {
155 #ifdef CONFIG_SYS_RTC_REG_BASE_ADDR
156 	out8(CONFIG_SYS_RTC_REG_BASE_ADDR + reg, val);
157 #else
158 	int ofs = 0;
159 
160 	if (reg >= 128) {
161 		ofs = 2;
162 		reg -= 128;
163 	}
164 	out8(RTC_PORT_MC146818 + ofs, reg);
165 	out8(RTC_PORT_MC146818 + ofs + 1, val);
166 #endif
167 }
168 
169 u32 rtc_read32(int reg)
170 {
171 	u32 value = 0;
172 	int i;
173 
174 	for (i = 0; i < sizeof(value); i++)
175 		value |= rtc_read8(reg + i) << (i << 3);
176 
177 	return value;
178 }
179 
180 void rtc_write32(int reg, u32 value)
181 {
182 	int i;
183 
184 	for (i = 0; i < sizeof(value); i++)
185 		rtc_write8(reg + i, (value >> (i << 3)) & 0xff);
186 }
187 
188 void rtc_init(void)
189 {
190 #if CLEAR_CMOS
191 	int i;
192 
193 	rtc_write8(RTC_SECONDS_ALARM, 0);
194 	rtc_write8(RTC_MINUTES_ALARM, 0);
195 	rtc_write8(RTC_HOURS_ALARM, 0);
196 	for (i = RTC_CONFIG_A; i < RTC_REG_SIZE; i++)
197 		rtc_write8(i, 0);
198 	printf("RTC: zeroing CMOS RAM\n");
199 #endif
200 
201 	/* Setup the real time clock */
202 	rtc_write8(RTC_CONFIG_B, RTC_CONFIG_B_24H);
203 	/* Setup the frequency it operates at */
204 	rtc_write8(RTC_CONFIG_A, RTC_CONFIG_A_REF_CLCK_32KHZ |
205 		  RTC_CONFIG_A_RATE_1024HZ);
206 	/* Ensure all reserved bits are 0 in register D */
207 	rtc_write8(RTC_CONFIG_D, RTC_CONFIG_D_VALID_RAM_AND_TIME);
208 
209 	/* Clear any pending interrupts */
210 	rtc_read8(RTC_CONFIG_C);
211 }
212 #endif
213