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65 lines
1.9 KiB
C
65 lines
1.9 KiB
C
#include "rtc.h"
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#include <common/kprint.h>
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/*置位0x70的第7位，禁止不可屏蔽中断*/
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/*
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#define read_cmos(addr) ({ \
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io_out8(0x70, 0x80 | addr); \
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io_in8(0x71); \
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})
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*/
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enum CMOSTimeSelector
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{
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T_SECOND = 0x0,
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T_MINUTE = 0x2,
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T_HOUR = 0x4,
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T_DAY = 0x7,
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T_MONTH = 0x8,
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T_YEAR = 0x9,
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};
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int read_cmos(uint8_t addr)
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{
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io_out8(0x70, 0x80 | addr);
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io_mfence();
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return (uint8_t)(io_in8(0x71) & 0xff);
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}
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int rtc_get_cmos_time(struct time *t)
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{
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// 为防止中断请求打断该过程，需要先关中断
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cli();
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uint8_t status_register_B = read_cmos(0x0B); // 读取状态寄存器B
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bool is_24h = ((status_register_B & 0x02) ? true : false); // 判断是否启用24小时模式
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bool is_binary = ((status_register_B & 0x04) ? true : false); // 判断是否为二进制码
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do
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{
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t->year = read_cmos(0x09);
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t->month = read_cmos(0x08);
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t->day = read_cmos(0x07);
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t->hour = read_cmos(0x04);
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t->minute = read_cmos(0x02);
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t->second = read_cmos(0x00);
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} while (t->second != read_cmos(0x00)); // 若读取时间过程中时间发生跳变则重新读取
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// 使能NMI中断
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io_out8(0x70, 0x00);
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if (!is_binary) // 把BCD转为二进制
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{
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t->second = (t->second & 0xf) + (t->second >> 4) * 10;
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t->minute = (t->minute & 0xf) + (t->minute >> 4) * 10;
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t->hour = ((t->hour & 0xf) + ((t->hour & 0x70) >> 4) * 10) | (t->hour & 0x80);
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t->month = (t->month & 0xf) + (t->month >> 4) * 10;
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t->year = (t->year & 0xf) + (t->year >> 4) * 10;
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}
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t->year += 2000;
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if ((!is_24h) && t->hour & 0x80) // 将十二小时制转为24小时
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t->hour = ((t->hour & 0x7f) + 12) % 24;
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sti();
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return 0;
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}
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