banan-os/kernel/kernel/RTC.cpp

127 lines
3.3 KiB
C++

#include <kernel/IO.h>
#include <kernel/RTC.h>
#include <string.h>
#define CURRENT_YEAR 2022
#define CMOS_ADDRESS 0x70
#define CMOS_DATA 0x71
#define CMOS_REGISTER_SECOND 0x00
#define CMOS_REGISTER_MINUTE 0x02
#define CMOS_REGISTER_HOUR 0x04
#define CMOS_REGISTER_WEEK_DAY 0x06
#define CMOS_REGISTER_DAY 0x07
#define CMOS_REGISTER_MONTH 0x08
#define CMOS_REGISTER_YEAR 0x09
#define CMOS_REGISTER_STATUS_1 0x0A
#define CMOS_REGISTER_STATUS_2 0x0B
namespace RTC
{
static bool get_update_in_progress()
{
IO::outb(CMOS_ADDRESS, CMOS_REGISTER_STATUS_1);
return IO::inb(CMOS_DATA) & 0x80;
}
static uint8_t get_rtc_register(uint8_t reg)
{
IO::outb(CMOS_ADDRESS, reg);
return IO::inb(CMOS_DATA);
}
static void get_time(BAN::Time& out)
{
out.second = get_rtc_register(CMOS_REGISTER_SECOND);
out.minute = get_rtc_register(CMOS_REGISTER_MINUTE);
out.hour = get_rtc_register(CMOS_REGISTER_HOUR);
out.week_day = get_rtc_register(CMOS_REGISTER_WEEK_DAY);
out.day = get_rtc_register(CMOS_REGISTER_DAY);
out.month = get_rtc_register(CMOS_REGISTER_MONTH);
out.year = get_rtc_register(CMOS_REGISTER_YEAR);
}
BAN::Time get_current_time()
{
BAN::Time last_time = {};
BAN::Time time = {};
while (get_update_in_progress())
continue;
get_time(time);
last_time.second = time.second + 1;
while (memcmp(&last_time, &time, sizeof(BAN::Time)))
{
last_time = time;
get_time(time);
}
uint8_t regB = get_rtc_register(0x0B);
// Convert BCD to binary values if necessary
if (!(regB & 0x04))
{
time.second = (time.second & 0x0F) + ((time.second / 16) * 10);
time.minute = (time.minute & 0x0F) + ((time.minute / 16) * 10);
time.hour = ((time.hour & 0x0F) + (((time.hour & 0x70) / 16) * 10) ) | (time.hour & 0x80);
time.week_day = (time.week_day & 0x0F) + ((time.week_day / 16) * 10);
time.day = (time.day & 0x0F) + ((time.day / 16) * 10);
time.month = (time.month & 0x0F) + ((time.month / 16) * 10);
time.year = (time.year & 0x0F) + ((time.year / 16) * 10);
}
// Convert 12 hour clock to 24 hour clock if necessary
if (!(regB & 0x02) && (time.hour & 0x80))
time.hour = ((time.hour & 0x7F) + 12) % 24;
// Calculate the full 4 digit year
time.year += (CURRENT_YEAR / 100) * 100;
if (time.year < CURRENT_YEAR)
time.year += 100;
return time;
}
static bool is_leap_year(uint64_t year)
{
if (year % 400 == 0)
return true;
if (year % 100 == 0)
return false;
if (year % 4 == 0)
return true;
return false;
}
static uint64_t leap_days_since_epoch(const BAN::Time& time)
{
uint64_t leap_years = 0;
for (int year = 1970; year < time.year; year++)
if (is_leap_year(year))
leap_years++;
if (is_leap_year(time.year))
if (time.month >= 3 || (time.month == 2 && time.day == 29))
leap_years++;
return leap_years;
}
uint64_t get_unix_time()
{
auto time = get_current_time();
uint64_t month_days[] { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
uint64_t years = time.year - 1970;
uint64_t days = years * 365 + month_days[time.month - 1] + time.day + leap_days_since_epoch(time) - 1;
uint64_t hours = days * 24 + time.hour;
uint64_t minutes = hours * 60 + time.minute;
uint64_t seconds = minutes * 60 + time.second;
return seconds;
}
}