diff options
Diffstat (limited to 'kernel/drivers/cmos.c')
| -rw-r--r-- | kernel/drivers/cmos.c | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/kernel/drivers/cmos.c b/kernel/drivers/cmos.c new file mode 100644 index 0000000..5f6ed34 --- /dev/null +++ b/kernel/drivers/cmos.c @@ -0,0 +1,78 @@ +#include "drivers/cmos.h" + +int cmos_update_flag_set() +{ + outb(CMOS_ADDR, CMOS_REG_STAT_A); + return (inb(CMOS_DATA) & 0x80); +} + +unsigned char cmos_read_register(int reg) +{ + outb(CMOS_ADDR, reg); + return inb(CMOS_DATA); +} + +int rtc_time_match(rtc_time_t a, rtc_time_t b) +{ + return (a.second == b.second) && (a.minute == b.minute) && + (a.hour == b.hour) && (a.day == b.day) && (a.month == b.month) && + (a.year == b.year) && (a.__century == b.__century); +} + +rtc_time_t __get_rtc_time() +{ + rtc_time_t tm; + + while (cmos_update_flag_set()) + ; + + tm.second = cmos_read_register(CMOS_REG_SECOND); + tm.minute = cmos_read_register(CMOS_REG_MINUTE); + tm.hour = cmos_read_register(CMOS_REG_HOUR); + tm.day = cmos_read_register(CMOS_REG_DAY); + tm.month = cmos_read_register(CMOS_REG_MONTH); + tm.year = cmos_read_register(CMOS_REG_YEAR); + tm.__century = cmos_read_register(CMOS_REG_CENTURY); + + return tm; +} + +/* Our ticks -> time calculation is so suspect, we just get the time from the + * CMOS RTC */ +rtc_time_t rtc_get_time() +{ + // Check the result of CMOS twice to ensure we didn't get a torn read. + rtc_time_t tm_a; + rtc_time_t tm_b; + + do + { + tm_a = __get_rtc_time(); + tm_b = __get_rtc_time(); + } while (!rtc_time_match(tm_a, tm_b)); + + unsigned char cmos_settings = cmos_read_register(CMOS_REG_STAT_B); + + // Convert from BCD + if (!(cmos_settings & 0x04)) + { + tm_a.second = (tm_a.second & 0x0F) + ((tm_a.second / 16) * 10); + tm_a.minute = (tm_a.minute & 0x0F) + ((tm_a.minute / 16) * 10); + tm_a.hour = ((tm_a.hour & 0x0F) + (((tm_a.hour & 0x70) / 16) * 10)) | + (tm_a.hour & 0x80); + tm_a.day = (tm_a.day & 0x0F) + ((tm_a.day / 16) * 10); + tm_a.month = (tm_a.month & 0x0F) + ((tm_a.month / 16) * 10); + tm_a.year = (tm_a.year & 0x0F) + ((tm_a.year / 16) * 10); + tm_a.__century = (tm_a.__century & 0x0F) + ((tm_a.__century / 16) * 10); + } + + // Convert 12-hour clock to 24-hour clock: + if (!(cmos_settings & 0x02) && (tm_a.hour & 0x80)) + { + tm_a.hour = ((tm_a.hour & 0x7F) + 12) % 24; + } + + tm_a.year += (tm_a.__century * 100); + + return tm_a; +}
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