1 // SPDX-License-Identifier: GPL-2.0+
4 * Denis Peter MPL AG Switzerland. d.peter@mpl.ch
8 * Date & Time support for the MC146818 (PIXX4) RTC
16 #if defined(CONFIG_X86) || defined(CONFIG_MALTA)
19 #define out8(p, v) outb(v, p)
22 #if defined(CONFIG_CMD_DATE)
24 /* Set this to 1 to clear the CMOS RAM */
27 #define RTC_PORT_MC146818 CONFIG_SYS_ISA_IO_BASE_ADDRESS + 0x70
28 #define RTC_SECONDS 0x00
29 #define RTC_SECONDS_ALARM 0x01
30 #define RTC_MINUTES 0x02
31 #define RTC_MINUTES_ALARM 0x03
32 #define RTC_HOURS 0x04
33 #define RTC_HOURS_ALARM 0x05
34 #define RTC_DAY_OF_WEEK 0x06
35 #define RTC_DATE_OF_MONTH 0x07
36 #define RTC_MONTH 0x08
38 #define RTC_CONFIG_A 0x0a
39 #define RTC_CONFIG_B 0x0b
40 #define RTC_CONFIG_C 0x0c
41 #define RTC_CONFIG_D 0x0d
42 #define RTC_REG_SIZE 0x80
44 #define RTC_CONFIG_A_REF_CLCK_32KHZ (1 << 5)
45 #define RTC_CONFIG_A_RATE_1024HZ 6
47 #define RTC_CONFIG_B_24H (1 << 1)
49 #define RTC_CONFIG_D_VALID_RAM_AND_TIME 0x80
51 static int mc146818_read8(int reg)
53 #ifdef CONFIG_SYS_RTC_REG_BASE_ADDR
54 return in8(CONFIG_SYS_RTC_REG_BASE_ADDR + reg);
62 out8(RTC_PORT_MC146818 + ofs, reg);
64 return in8(RTC_PORT_MC146818 + ofs + 1);
68 static void mc146818_write8(int reg, uchar val)
70 #ifdef CONFIG_SYS_RTC_REG_BASE_ADDR
71 out8(CONFIG_SYS_RTC_REG_BASE_ADDR + reg, val);
79 out8(RTC_PORT_MC146818 + ofs, reg);
80 out8(RTC_PORT_MC146818 + ofs + 1, val);
84 static int mc146818_get(struct rtc_time *tmp)
86 uchar sec, min, hour, mday, wday __attribute__((unused)),mon, year;
88 /* here check if rtc can be accessed */
89 while ((mc146818_read8(RTC_CONFIG_A) & 0x80) == 0x80)
92 sec = mc146818_read8(RTC_SECONDS);
93 min = mc146818_read8(RTC_MINUTES);
94 hour = mc146818_read8(RTC_HOURS);
95 mday = mc146818_read8(RTC_DATE_OF_MONTH);
96 wday = mc146818_read8(RTC_DAY_OF_WEEK);
97 mon = mc146818_read8(RTC_MONTH);
98 year = mc146818_read8(RTC_YEAR);
100 printf("Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x hr: %02x min: %02x sec: %02x\n",
101 year, mon, mday, wday, hour, min, sec);
102 printf("Alarms: mday: %02x hour: %02x min: %02x sec: %02x\n",
103 mc146818_read8(RTC_CONFIG_D) & 0x3f,
104 mc146818_read8(RTC_HOURS_ALARM),
105 mc146818_read8(RTC_MINUTES_ALARM),
106 mc146818_read8(RTC_SECONDS_ALARM));
108 tmp->tm_sec = bcd2bin(sec & 0x7f);
109 tmp->tm_min = bcd2bin(min & 0x7f);
110 tmp->tm_hour = bcd2bin(hour & 0x3f);
111 tmp->tm_mday = bcd2bin(mday & 0x3f);
112 tmp->tm_mon = bcd2bin(mon & 0x1f);
113 tmp->tm_year = bcd2bin(year);
115 if (tmp->tm_year < 70)
116 tmp->tm_year += 2000;
118 tmp->tm_year += 1900;
123 * The mc146818 only updates wday if it is non-zero, sunday is 1
124 * saturday is 7. So let's use our library routine.
126 rtc_calc_weekday(tmp);
128 printf("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
129 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
130 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
136 static int mc146818_set(struct rtc_time *tmp)
139 printf("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
140 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
141 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
143 /* Disable the RTC to update the regs */
144 mc146818_write8(RTC_CONFIG_B, 0x82);
146 mc146818_write8(RTC_YEAR, bin2bcd(tmp->tm_year % 100));
147 mc146818_write8(RTC_MONTH, bin2bcd(tmp->tm_mon));
148 /* Sunday = 1, Saturday = 7 */
149 mc146818_write8(RTC_DAY_OF_WEEK, bin2bcd(tmp->tm_wday + 1));
150 mc146818_write8(RTC_DATE_OF_MONTH, bin2bcd(tmp->tm_mday));
151 mc146818_write8(RTC_HOURS, bin2bcd(tmp->tm_hour));
152 mc146818_write8(RTC_MINUTES, bin2bcd(tmp->tm_min));
153 mc146818_write8(RTC_SECONDS, bin2bcd(tmp->tm_sec));
155 /* Enable the RTC to update the regs */
156 mc146818_write8(RTC_CONFIG_B, 0x02);
161 static void mc146818_reset(void)
163 /* Disable the RTC to update the regs */
164 mc146818_write8(RTC_CONFIG_B, 0x82);
167 mc146818_write8(RTC_CONFIG_A, 0x20);
168 mc146818_write8(RTC_CONFIG_B, 0x00);
169 mc146818_write8(RTC_CONFIG_B, 0x00);
171 /* Enable the RTC to update the regs */
172 mc146818_write8(RTC_CONFIG_B, 0x02);
175 static void mc146818_init(void)
180 rtc_write8(RTC_SECONDS_ALARM, 0);
181 rtc_write8(RTC_MINUTES_ALARM, 0);
182 rtc_write8(RTC_HOURS_ALARM, 0);
183 for (i = RTC_CONFIG_A; i < RTC_REG_SIZE; i++)
185 printf("RTC: zeroing CMOS RAM\n");
188 /* Setup the real time clock */
189 mc146818_write8(RTC_CONFIG_B, RTC_CONFIG_B_24H);
190 /* Setup the frequency it operates at */
191 mc146818_write8(RTC_CONFIG_A, RTC_CONFIG_A_REF_CLCK_32KHZ |
192 RTC_CONFIG_A_RATE_1024HZ);
193 /* Ensure all reserved bits are 0 in register D */
194 mc146818_write8(RTC_CONFIG_D, RTC_CONFIG_D_VALID_RAM_AND_TIME);
196 /* Clear any pending interrupts */
197 mc146818_read8(RTC_CONFIG_C);
199 #endif /* CONFIG_CMD_DATE */
203 static int rtc_mc146818_get(struct udevice *dev, struct rtc_time *time)
205 return mc146818_get(time);
208 static int rtc_mc146818_set(struct udevice *dev, const struct rtc_time *time)
210 return mc146818_set((struct rtc_time *)time);
213 static int rtc_mc146818_reset(struct udevice *dev)
220 static int rtc_mc146818_read8(struct udevice *dev, unsigned int reg)
222 return mc146818_read8(reg);
225 static int rtc_mc146818_write8(struct udevice *dev, unsigned int reg, int val)
227 mc146818_write8(reg, val);
232 static int rtc_mc146818_probe(struct udevice *dev)
239 static const struct rtc_ops rtc_mc146818_ops = {
240 .get = rtc_mc146818_get,
241 .set = rtc_mc146818_set,
242 .reset = rtc_mc146818_reset,
243 .read8 = rtc_mc146818_read8,
244 .write8 = rtc_mc146818_write8,
247 static const struct udevice_id rtc_mc146818_ids[] = {
248 { .compatible = "motorola,mc146818" },
252 U_BOOT_DRIVER(rtc_mc146818) = {
253 .name = "rtc_mc146818",
255 .of_match = rtc_mc146818_ids,
256 .probe = rtc_mc146818_probe,
257 .ops = &rtc_mc146818_ops,
260 #else /* !CONFIG_DM_RTC */
262 int rtc_get(struct rtc_time *tmp)
264 return mc146818_get(tmp);
267 int rtc_set(struct rtc_time *tmp)
269 return mc146818_set(tmp);
277 int rtc_read8(int reg)
279 return mc146818_read8(reg);
282 void rtc_write8(int reg, uchar val)
284 mc146818_write8(reg, val);
287 u32 rtc_read32(int reg)
292 for (i = 0; i < sizeof(value); i++)
293 value |= rtc_read8(reg + i) << (i << 3);
298 void rtc_write32(int reg, u32 value)
302 for (i = 0; i < sizeof(value); i++)
303 rtc_write8(reg + i, (value >> (i << 3)) & 0xff);
311 #endif /* CONFIG_DM_RTC */