| 1 | /*␊ |
| 2 | * http://wiki.osdev.org/OSDev_Wiki:General_disclaimer␊ |
| 3 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR␊ |
| 4 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,␊ |
| 5 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE␊ |
| 6 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER␊ |
| 7 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,␊ |
| 8 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN␊ |
| 9 | * THE SOFTWARE.␊ |
| 10 | */␊ |
| 11 | #include "libsaio.h"␊ |
| 12 | ␊ |
| 13 | #define CURRENT_YEAR 2012 // Change this each year!␊ |
| 14 | ␊ |
| 15 | static int century_register = 0x00; // Set by ACPI table parsing code if possible(... in FADT table)␊ |
| 16 | ␊ |
| 17 | enum {␊ |
| 18 | cmos_address = 0x70,␊ |
| 19 | cmos_data = 0x71␊ |
| 20 | };␊ |
| 21 | ␊ |
| 22 | ␊ |
| 23 | static int get_update_in_progress_flag() {␊ |
| 24 | outb(cmos_address, 0x0A);␊ |
| 25 | return (inb(cmos_data) & 0x80);␊ |
| 26 | }␊ |
| 27 | ␊ |
| 28 | ␊ |
| 29 | static unsigned char get_RTC_register(int reg) {␊ |
| 30 | outb(cmos_address, reg);␊ |
| 31 | return inb(cmos_data);␊ |
| 32 | }␊ |
| 33 | ␊ |
| 34 | void rtc_read_clock(struct tm *time) {␊ |
| 35 | unsigned char century = 0;␊ |
| 36 | unsigned char last_second;␊ |
| 37 | unsigned char last_minute;␊ |
| 38 | unsigned char last_hour;␊ |
| 39 | unsigned char last_day;␊ |
| 40 | unsigned char last_month;␊ |
| 41 | unsigned char last_year;␊ |
| 42 | unsigned char last_century;␊ |
| 43 | unsigned char registerB;␊ |
| 44 | ␊ |
| 45 | unsigned char second;␊ |
| 46 | unsigned char minute;␊ |
| 47 | unsigned char hour;␊ |
| 48 | unsigned char day;␊ |
| 49 | unsigned char month;␊ |
| 50 | unsigned int year;␊ |
| 51 | // Note: This uses the "read registers until you get the same values twice in a row" technique␊ |
| 52 | // to avoid getting dodgy/inconsistent values due to RTC updates␊ |
| 53 | ␊ |
| 54 | while (get_update_in_progress_flag()); // Make sure an update isn't in progress␊ |
| 55 | second = get_RTC_register(0x00);␊ |
| 56 | minute = get_RTC_register(0x02);␊ |
| 57 | hour = get_RTC_register(0x04);␊ |
| 58 | day = get_RTC_register(0x07);␊ |
| 59 | month = get_RTC_register(0x08);␊ |
| 60 | year = get_RTC_register(0x09);␊ |
| 61 | if(century_register != 0) {␊ |
| 62 | century = get_RTC_register(century_register);␊ |
| 63 | }␊ |
| 64 | ␊ |
| 65 | do {␊ |
| 66 | last_second = second;␊ |
| 67 | last_minute = minute;␊ |
| 68 | last_hour = hour;␊ |
| 69 | last_day = day;␊ |
| 70 | last_month = month;␊ |
| 71 | last_year = year;␊ |
| 72 | last_century = century;␊ |
| 73 | ␊ |
| 74 | while (get_update_in_progress_flag()); // Make sure an update isn't in progress␊ |
| 75 | second = get_RTC_register(0x00);␊ |
| 76 | minute = get_RTC_register(0x02);␊ |
| 77 | hour = get_RTC_register(0x04);␊ |
| 78 | day = get_RTC_register(0x07);␊ |
| 79 | month = get_RTC_register(0x08);␊ |
| 80 | year = get_RTC_register(0x09);␊ |
| 81 | if(century_register != 0) {␊ |
| 82 | century = get_RTC_register(century_register);␊ |
| 83 | }␊ |
| 84 | } while( (last_second == second) && (last_minute == minute) && (last_hour == hour) &&␊ |
| 85 | (last_day == day) && (last_month == month) && (last_year == year) &&␊ |
| 86 | (last_century == century) );␊ |
| 87 | ␊ |
| 88 | registerB = get_RTC_register(0x0B);␊ |
| 89 | ␊ |
| 90 | // Convert BCD to binary values if necessary␊ |
| 91 | ␊ |
| 92 | if (!(registerB & 0x04)) {␊ |
| 93 | second = (second & 0x0F) + ((second / 16) * 10);␊ |
| 94 | minute = (minute & 0x0F) + ((minute / 16) * 10);␊ |
| 95 | hour = ( (hour & 0x0F) + (((hour & 0x70) / 16) * 10) ) | (hour & 0x80);␊ |
| 96 | day = (day & 0x0F) + ((day / 16) * 10);␊ |
| 97 | month = (month & 0x0F) + ((month / 16) * 10);␊ |
| 98 | year = (year & 0x0F) + ((year / 16) * 10);␊ |
| 99 | if(century_register != 0) {␊ |
| 100 | century = (century & 0x0F) + ((century / 16) * 10);␊ |
| 101 | }␊ |
| 102 | } ␊ |
| 103 | ␊ |
| 104 | // Calculate the full (4-digit) year␊ |
| 105 | ␊ |
| 106 | if(century_register != 0) {␊ |
| 107 | year += century * 100;␊ |
| 108 | } else {␊ |
| 109 | //year += (CURRENT_YEAR / 100) * 100;␊ |
| 110 | //if(year < CURRENT_YEAR) year += 100; ␊ |
| 111 | ␊ |
| 112 | if ((year += 1900) < 1970)␊ |
| 113 | year += 100;␊ |
| 114 | }␊ |
| 115 | ␊ |
| 116 | time->tm_sec = second;␊ |
| 117 | time->tm_min = minute;␊ |
| 118 | time->tm_hour = hour;␊ |
| 119 | time->tm_mday = day;␊ |
| 120 | time->tm_mon = month;␊ |
| 121 | time->tm_year = year;␊ |
| 122 | }␊ |
| 123 | |
