lunaix-os/hal/rtc.c

   1 /**
   2  * @file rtc.c
   3  * @author Lunaixsky
   4  * @brief RTC & CMOS abstraction. Reference: MC146818A & Intel Series 500 PCH datasheet
   5  * @version 0.1
   6  * @date 2022-03-07
   7  *
   8  * @copyright Copyright (c) 2022
   9  *
  10  */
  11 #include <hal/rtc.h>
  12 #include <lunaix/time.h>
  13 #include <klibc/string.h>
  14
  15 void
  16 rtc_init() {
  17     uint8_t regA = rtc_read_reg(RTC_REG_A | WITH_NMI_DISABLED);
  18     regA = (regA & ~0x7f) | RTC_FREQUENCY_1024HZ | RTC_DIVIDER_33KHZ;
  19     rtc_write_reg(RTC_REG_A | WITH_NMI_DISABLED, regA);
  20
  21     // Make sure the rtc timer is disabled by default
  22     rtc_disable_timer();
  23 }
  24
  25 uint8_t
  26 rtc_read_reg(uint8_t reg_selector)
  27 {
  28     io_outb(RTC_INDEX_PORT, reg_selector);
  29     return io_inb(RTC_TARGET_PORT);
  30 }
  31
  32 void
  33 rtc_write_reg(uint8_t reg_selector, uint8_t val)
  34 {
  35     io_outb(RTC_INDEX_PORT, reg_selector);
  36     io_outb(RTC_TARGET_PORT, val);
  37 }
  38
  39 uint8_t
  40 bcd2dec(uint8_t bcd)
  41 {
  42     return ((bcd & 0xF0) >> 1) + ((bcd & 0xF0) >> 3) + (bcd & 0xf);
  43 }
  44
  45 int
  46 rtc_date_same(datetime_t* a, datetime_t* b) {
  47     return a->year == b->year &&
  48            a->month == b->month &&
  49            a->day == b->day &&
  50            a->weekday == b->weekday &&
  51            a->minute == b->minute &&
  52            a->second == b->second;
  53 }
  54
  55 void
  56 time_getdatetime(datetime_t* datetime)
  57 {
  58     datetime_t current;
  59
  60     do
  61     {
  62         while (rtc_read_reg(RTC_REG_A) & 0x80);
  63         memcpy(&current, datetime, sizeof(datetime_t));
  64
  65         datetime->year = rtc_read_reg(RTC_REG_YRS);
  66         datetime->month = rtc_read_reg(RTC_REG_MTH);
  67         datetime->day = rtc_read_reg(RTC_REG_DAY);
  68         datetime->weekday = rtc_read_reg(RTC_REG_WDY);
  69         datetime->hour = rtc_read_reg(RTC_REG_HRS);
  70         datetime->minute = rtc_read_reg(RTC_REG_MIN);
  71         datetime->second = rtc_read_reg(RTC_REG_SEC);
  72     } while (!rtc_date_same(datetime, &current));
  73
  74     uint8_t regbv = rtc_read_reg(RTC_REG_B);
  75
  76     // Convert from bcd to binary when needed
  77     if (!RTC_BIN_ENCODED(regbv)) {
  78         datetime->year = bcd2dec(datetime->year);
  79         datetime->month = bcd2dec(datetime->month);
  80         datetime->day = bcd2dec(datetime->day);
  81         datetime->hour = bcd2dec(datetime->hour);
  82         datetime->minute = bcd2dec(datetime->minute);
  83         datetime->second = bcd2dec(datetime->second);
  84     }
  85
  86
  87     // To 24 hour format
  88     if (!RTC_24HRS_ENCODED(regbv) && (datetime->hour >> 7)) {
  89         datetime->hour = (12 + datetime->hour & 0x80);
  90     }
  91
  92     datetime->year += RTC_CURRENT_CENTRY * 100;
  93 }
  94
  95 void
  96 rtc_enable_timer() {
  97     uint8_t regB = rtc_read_reg(RTC_REG_B | WITH_NMI_DISABLED);
  98     rtc_write_reg(RTC_REG_B | WITH_NMI_DISABLED, regB | RTC_TIMER_ON);
  99 }
 100
 101 void
 102 rtc_disable_timer() {
 103     uint8_t regB = rtc_read_reg(RTC_REG_B | WITH_NMI_DISABLED);
 104     rtc_write_reg(RTC_REG_B | WITH_NMI_DISABLED, regB & ~RTC_TIMER_ON);
 105 }