1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * (C) Copyright 2001
4 * ARIO Data Networks, Inc. dchiu@ariodata.com
5 *
6 * Based on MontaVista DS1743 code and U-Boot mc146818 code
7 */
8
9 /*
10 * Date & Time support for the DS174x RTC
11 */
12
13 /*#define DEBUG*/
14
15 #include <common.h>
16 #include <command.h>
17 #include <rtc.h>
18
19 static uchar rtc_read( unsigned int addr );
20 static void rtc_write( unsigned int addr, uchar val);
21
22 #define RTC_BASE ( CONFIG_SYS_NVRAM_SIZE + CONFIG_SYS_NVRAM_BASE_ADDR )
23
24 #define RTC_YEAR ( RTC_BASE + 7 )
25 #define RTC_MONTH ( RTC_BASE + 6 )
26 #define RTC_DAY_OF_MONTH ( RTC_BASE + 5 )
27 #define RTC_DAY_OF_WEEK ( RTC_BASE + 4 )
28 #define RTC_HOURS ( RTC_BASE + 3 )
29 #define RTC_MINUTES ( RTC_BASE + 2 )
30 #define RTC_SECONDS ( RTC_BASE + 1 )
31 #define RTC_CENTURY ( RTC_BASE + 0 )
32
33 #define RTC_CONTROLA RTC_CENTURY
34 #define RTC_CONTROLB RTC_SECONDS
35 #define RTC_CONTROLC RTC_DAY_OF_WEEK
36
37 #define RTC_CA_WRITE 0x80
38 #define RTC_CA_READ 0x40
39
40 #define RTC_CB_OSC_DISABLE 0x80
41
42 #define RTC_CC_BATTERY_FLAG 0x80
43 #define RTC_CC_FREQ_TEST 0x40
44
45 /* ------------------------------------------------------------------------- */
46
rtc_get(struct rtc_time * tmp)47 int rtc_get( struct rtc_time *tmp )
48 {
49 uchar sec, min, hour;
50 uchar mday, wday, mon, year;
51
52 int century;
53
54 uchar reg_a;
55
56 reg_a = rtc_read( RTC_CONTROLA );
57 /* lock clock registers for read */
58 rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_READ ));
59
60 sec = rtc_read( RTC_SECONDS );
61 min = rtc_read( RTC_MINUTES );
62 hour = rtc_read( RTC_HOURS );
63 mday = rtc_read( RTC_DAY_OF_MONTH );
64 wday = rtc_read( RTC_DAY_OF_WEEK );
65 mon = rtc_read( RTC_MONTH );
66 year = rtc_read( RTC_YEAR );
67 century = rtc_read( RTC_CENTURY );
68
69 /* unlock clock registers after read */
70 rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_READ ));
71
72 #ifdef RTC_DEBUG
73 printf( "Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x "
74 "hr: %02x min: %02x sec: %02x\n",
75 year, mon_cent, mday, wday,
76 hour, min, sec );
77 #endif
78 tmp->tm_sec = bcd2bin( sec & 0x7F );
79 tmp->tm_min = bcd2bin( min & 0x7F );
80 tmp->tm_hour = bcd2bin( hour & 0x3F );
81 tmp->tm_mday = bcd2bin( mday & 0x3F );
82 tmp->tm_mon = bcd2bin( mon & 0x1F );
83 tmp->tm_wday = bcd2bin( wday & 0x07 );
84
85 /* glue year from century and year in century */
86 tmp->tm_year = bcd2bin( year ) +
87 ( bcd2bin( century & 0x3F ) * 100 );
88
89 tmp->tm_yday = 0;
90 tmp->tm_isdst= 0;
91 #ifdef RTC_DEBUG
92 printf( "Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
93 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
94 tmp->tm_hour, tmp->tm_min, tmp->tm_sec );
95 #endif
96 return 0;
97 }
98
rtc_set(struct rtc_time * tmp)99 int rtc_set( struct rtc_time *tmp )
100 {
101 uchar reg_a;
102 #ifdef RTC_DEBUG
103 printf( "Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
104 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
105 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
106 #endif
107 /* lock clock registers for write */
108 reg_a = rtc_read( RTC_CONTROLA );
109 rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_WRITE ));
110
111 rtc_write( RTC_MONTH, bin2bcd( tmp->tm_mon ));
112
113 rtc_write( RTC_DAY_OF_WEEK, bin2bcd( tmp->tm_wday ));
114 rtc_write( RTC_DAY_OF_MONTH, bin2bcd( tmp->tm_mday ));
115 rtc_write( RTC_HOURS, bin2bcd( tmp->tm_hour ));
116 rtc_write( RTC_MINUTES, bin2bcd( tmp->tm_min ));
117 rtc_write( RTC_SECONDS, bin2bcd( tmp->tm_sec ));
118
119 /* break year up into century and year in century */
120 rtc_write( RTC_YEAR, bin2bcd( tmp->tm_year % 100 ));
121 rtc_write( RTC_CENTURY, bin2bcd( tmp->tm_year / 100 ));
122
123 /* unlock clock registers after read */
124 rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_WRITE ));
125
126 return 0;
127 }
128
rtc_reset(void)129 void rtc_reset (void)
130 {
131 uchar reg_a, reg_b, reg_c;
132
133 reg_a = rtc_read( RTC_CONTROLA );
134 reg_b = rtc_read( RTC_CONTROLB );
135
136 if ( reg_b & RTC_CB_OSC_DISABLE )
137 {
138 printf( "real-time-clock was stopped. Now starting...\n" );
139 reg_a |= RTC_CA_WRITE;
140 reg_b &= ~RTC_CB_OSC_DISABLE;
141
142 rtc_write( RTC_CONTROLA, reg_a );
143 rtc_write( RTC_CONTROLB, reg_b );
144 }
145
146 /* make sure read/write clock register bits are cleared */
147 reg_a &= ~( RTC_CA_WRITE | RTC_CA_READ );
148 rtc_write( RTC_CONTROLA, reg_a );
149
150 reg_c = rtc_read( RTC_CONTROLC );
151 if (( reg_c & RTC_CC_BATTERY_FLAG ) == 0 )
152 printf( "RTC battery low. Clock setting may not be reliable.\n" );
153 }
154
155 /* ------------------------------------------------------------------------- */
156
rtc_read(unsigned int addr)157 static uchar rtc_read( unsigned int addr )
158 {
159 uchar val = in8( addr );
160 #ifdef RTC_DEBUG
161 printf( "rtc_read: %x:%x\n", addr, val );
162 #endif
163 return( val );
164 }
165
rtc_write(unsigned int addr,uchar val)166 static void rtc_write( unsigned int addr, uchar val )
167 {
168 #ifdef RTC_DEBUG
169 printf( "rtc_write: %x:%x\n", addr, val );
170 #endif
171 out8( addr, val );
172 }
173