3 * Denis Peter MPL AG Switzerland. d.peter@mpl.ch
5 * SPDX-License-Identifier: GPL-2.0+
9 * Date & Time support for the MC146818 (PIXX4) RTC
19 #if defined(__I386__) || defined(CONFIG_MALTA)
22 #define out8(p, v) outb(v, p)
25 #if defined(CONFIG_CMD_DATE)
27 /* Set this to 1 to clear the CMOS RAM */
30 static uchar rtc_read (uchar reg);
31 static void rtc_write (uchar reg, uchar val);
33 #define RTC_PORT_MC146818 CONFIG_SYS_ISA_IO_BASE_ADDRESS + 0x70
34 #define RTC_SECONDS 0x00
35 #define RTC_SECONDS_ALARM 0x01
36 #define RTC_MINUTES 0x02
37 #define RTC_MINUTES_ALARM 0x03
38 #define RTC_HOURS 0x04
39 #define RTC_HOURS_ALARM 0x05
40 #define RTC_DAY_OF_WEEK 0x06
41 #define RTC_DATE_OF_MONTH 0x07
42 #define RTC_MONTH 0x08
44 #define RTC_CONFIG_A 0x0A
45 #define RTC_CONFIG_B 0x0B
46 #define RTC_CONFIG_C 0x0C
47 #define RTC_CONFIG_D 0x0D
48 #define RTC_REG_SIZE 0x80
50 #define RTC_CONFIG_A_REF_CLCK_32KHZ (1 << 5)
51 #define RTC_CONFIG_A_RATE_1024HZ 6
53 #define RTC_CONFIG_B_24H (1 << 1)
55 #define RTC_CONFIG_D_VALID_RAM_AND_TIME 0x80
57 /* ------------------------------------------------------------------------- */
59 int rtc_get (struct rtc_time *tmp)
61 uchar sec, min, hour, mday, wday, mon, year;
62 /* here check if rtc can be accessed */
63 while((rtc_read(RTC_CONFIG_A)&0x80)==0x80);
64 sec = rtc_read (RTC_SECONDS);
65 min = rtc_read (RTC_MINUTES);
66 hour = rtc_read (RTC_HOURS);
67 mday = rtc_read (RTC_DATE_OF_MONTH);
68 wday = rtc_read (RTC_DAY_OF_WEEK);
69 mon = rtc_read (RTC_MONTH);
70 year = rtc_read (RTC_YEAR);
72 printf ( "Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x "
73 "hr: %02x min: %02x sec: %02x\n",
74 year, mon, mday, wday,
76 printf ( "Alarms: month: %02x hour: %02x min: %02x sec: %02x\n",
77 rtc_read (RTC_CONFIG_D) & 0x3F,
78 rtc_read (RTC_HOURS_ALARM),
79 rtc_read (RTC_MINUTES_ALARM),
80 rtc_read (RTC_SECONDS_ALARM) );
82 tmp->tm_sec = bcd2bin (sec & 0x7F);
83 tmp->tm_min = bcd2bin (min & 0x7F);
84 tmp->tm_hour = bcd2bin (hour & 0x3F);
85 tmp->tm_mday = bcd2bin (mday & 0x3F);
86 tmp->tm_mon = bcd2bin (mon & 0x1F);
87 tmp->tm_year = bcd2bin (year);
88 tmp->tm_wday = bcd2bin (wday & 0x07);
96 printf ( "Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
97 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
98 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
104 int rtc_set (struct rtc_time *tmp)
107 printf ( "Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
108 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
109 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
111 rtc_write(RTC_CONFIG_B,0x82); /* disables the RTC to update the regs */
113 rtc_write (RTC_YEAR, bin2bcd(tmp->tm_year % 100));
114 rtc_write (RTC_MONTH, bin2bcd(tmp->tm_mon));
115 rtc_write (RTC_DAY_OF_WEEK, bin2bcd(tmp->tm_wday));
116 rtc_write (RTC_DATE_OF_MONTH, bin2bcd(tmp->tm_mday));
117 rtc_write (RTC_HOURS, bin2bcd(tmp->tm_hour));
118 rtc_write (RTC_MINUTES, bin2bcd(tmp->tm_min ));
119 rtc_write (RTC_SECONDS, bin2bcd(tmp->tm_sec ));
120 rtc_write(RTC_CONFIG_B,0x02); /* enables the RTC to update the regs */
125 void rtc_reset (void)
127 rtc_write(RTC_CONFIG_B,0x82); /* disables the RTC to update the regs */
128 rtc_write(RTC_CONFIG_A,0x20); /* Normal OP */
129 rtc_write(RTC_CONFIG_B,0x00);
130 rtc_write(RTC_CONFIG_B,0x00);
131 rtc_write(RTC_CONFIG_B,0x02); /* enables the RTC to update the regs */
134 /* ------------------------------------------------------------------------- */
136 #ifdef CONFIG_SYS_RTC_REG_BASE_ADDR
138 * use direct memory access
140 static uchar rtc_read (uchar reg)
142 return in8(CONFIG_SYS_RTC_REG_BASE_ADDR + reg);
145 static void rtc_write (uchar reg, uchar val)
147 out8(CONFIG_SYS_RTC_REG_BASE_ADDR + reg, val);
150 static uchar rtc_read (uchar reg)
152 out8(RTC_PORT_MC146818,reg);
153 return in8(RTC_PORT_MC146818 + 1);
156 static void rtc_write (uchar reg, uchar val)
158 out8(RTC_PORT_MC146818,reg);
159 out8(RTC_PORT_MC146818+1, val);
168 rtc_write(RTC_SECONDS_ALARM, 0);
169 rtc_write(RTC_MINUTES_ALARM, 0);
170 rtc_write(RTC_HOURS_ALARM, 0);
171 for (i = RTC_CONFIG_A; i < RTC_REG_SIZE; i++)
173 printf("RTC: zeroing CMOS RAM\n");
176 /* Setup the real time clock */
177 rtc_write(RTC_CONFIG_B, RTC_CONFIG_B_24H);
178 /* Setup the frequency it operates at */
179 rtc_write(RTC_CONFIG_A, RTC_CONFIG_A_REF_CLCK_32KHZ |
180 RTC_CONFIG_A_RATE_1024HZ);
181 /* Ensure all reserved bits are 0 in register D */
182 rtc_write(RTC_CONFIG_D, RTC_CONFIG_D_VALID_RAM_AND_TIME);
184 /* Clear any pending interrupts */
185 rtc_read(RTC_CONFIG_C);