banan-os/kernel/kernel/RTC.cpp

90 lines
2.4 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 GetCurrentTime()
{
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;
}
}