^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) #include <linux/bcd.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) #include <linux/delay.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) #include <linux/export.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) #include <linux/mc146818rtc.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) #ifdef CONFIG_ACPI
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) #include <linux/acpi.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) * Returns true if a clock update is in progress
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) static inline unsigned char mc146818_is_updating(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) unsigned char uip;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) spin_lock_irqsave(&rtc_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) spin_unlock_irqrestore(&rtc_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) return uip;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) unsigned int mc146818_get_time(struct rtc_time *time)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) unsigned char ctrl;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) unsigned char century = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) #ifdef CONFIG_MACH_DECSTATION
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) unsigned int real_year;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) * read RTC once any update in progress is done. The update
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) * can take just over 2ms. We wait 20ms. There is no need to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) * If you need to know *exactly* when a second has started, enable
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) * periodic update complete interrupts, (via ioctl) and then
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) * immediately read /dev/rtc which will block until you get the IRQ.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) * Once the read clears, read the RTC time (again via ioctl). Easy.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) if (mc146818_is_updating())
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) mdelay(20);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) * Only the values that we read from the RTC are set. We leave
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) * tm_wday, tm_yday and tm_isdst untouched. Even though the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) * by the RTC when initially set to a non-zero value.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) spin_lock_irqsave(&rtc_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) time->tm_sec = CMOS_READ(RTC_SECONDS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) time->tm_min = CMOS_READ(RTC_MINUTES);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) time->tm_hour = CMOS_READ(RTC_HOURS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) time->tm_mon = CMOS_READ(RTC_MONTH);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) time->tm_year = CMOS_READ(RTC_YEAR);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) #ifdef CONFIG_MACH_DECSTATION
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) real_year = CMOS_READ(RTC_DEC_YEAR);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) #ifdef CONFIG_ACPI
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) acpi_gbl_FADT.century)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) century = CMOS_READ(acpi_gbl_FADT.century);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) ctrl = CMOS_READ(RTC_CONTROL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) spin_unlock_irqrestore(&rtc_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) time->tm_sec = bcd2bin(time->tm_sec);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) time->tm_min = bcd2bin(time->tm_min);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) time->tm_hour = bcd2bin(time->tm_hour);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) time->tm_mday = bcd2bin(time->tm_mday);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) time->tm_mon = bcd2bin(time->tm_mon);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) time->tm_year = bcd2bin(time->tm_year);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) century = bcd2bin(century);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) #ifdef CONFIG_MACH_DECSTATION
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) time->tm_year += real_year - 72;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) if (century > 19)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) time->tm_year += (century - 19) * 100;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) * Account for differences between how the RTC uses the values
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) * and how they are defined in a struct rtc_time;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) if (time->tm_year <= 69)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) time->tm_year += 100;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) time->tm_mon--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) return RTC_24H;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) EXPORT_SYMBOL_GPL(mc146818_get_time);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) /* Set the current date and time in the real time clock. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) int mc146818_set_time(struct rtc_time *time)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) unsigned char mon, day, hrs, min, sec;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) unsigned char save_control, save_freq_select;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) unsigned int yrs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) #ifdef CONFIG_MACH_DECSTATION
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) unsigned int real_yrs, leap_yr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) unsigned char century = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) yrs = time->tm_year;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) mon = time->tm_mon + 1; /* tm_mon starts at zero */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) day = time->tm_mday;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) hrs = time->tm_hour;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) min = time->tm_min;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) sec = time->tm_sec;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) if (yrs > 255) /* They are unsigned */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) spin_lock_irqsave(&rtc_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) #ifdef CONFIG_MACH_DECSTATION
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) real_yrs = yrs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) leap_yr = ((!((yrs + 1900) % 4) && ((yrs + 1900) % 100)) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) !((yrs + 1900) % 400));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) yrs = 72;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) * We want to keep the year set to 73 until March
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) * for non-leap years, so that Feb, 29th is handled
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) * correctly.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) if (!leap_yr && mon < 3) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) real_yrs--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) yrs = 73;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) #ifdef CONFIG_ACPI
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) acpi_gbl_FADT.century) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) century = (yrs + 1900) / 100;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) yrs %= 100;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) /* These limits and adjustments are independent of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) * whether the chip is in binary mode or not.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) if (yrs > 169) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) spin_unlock_irqrestore(&rtc_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) if (yrs >= 100)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) yrs -= 100;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) || RTC_ALWAYS_BCD) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) sec = bin2bcd(sec);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) min = bin2bcd(min);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) hrs = bin2bcd(hrs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) day = bin2bcd(day);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) mon = bin2bcd(mon);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) yrs = bin2bcd(yrs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) century = bin2bcd(century);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) save_control = CMOS_READ(RTC_CONTROL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) #ifdef CONFIG_MACH_DECSTATION
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) CMOS_WRITE(yrs, RTC_YEAR);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) CMOS_WRITE(mon, RTC_MONTH);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) CMOS_WRITE(day, RTC_DAY_OF_MONTH);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) CMOS_WRITE(hrs, RTC_HOURS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) CMOS_WRITE(min, RTC_MINUTES);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) CMOS_WRITE(sec, RTC_SECONDS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) #ifdef CONFIG_ACPI
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) acpi_gbl_FADT.century)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) CMOS_WRITE(century, acpi_gbl_FADT.century);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) CMOS_WRITE(save_control, RTC_CONTROL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) spin_unlock_irqrestore(&rtc_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) EXPORT_SYMBOL_GPL(mc146818_set_time);
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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