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		1682f0b760
		
	
	
	
	
		
			
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			88 lines
		
	
	
	
		
			2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			88 lines
		
	
	
	
		
			2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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|  *
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|  * SPDX-License-Identifier: BSD-2-Clause
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|  */
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| 
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| #include <AK/Assertions.h>
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| #include <AK/Time.h>
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| #include <Kernel/CMOS.h>
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| #include <Kernel/RTC.h>
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| 
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| namespace RTC {
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| 
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| static time_t s_boot_time;
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| 
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| void initialize()
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| {
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|     s_boot_time = now();
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| }
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| 
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| time_t boot_time()
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| {
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|     return s_boot_time;
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| }
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| 
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| static bool update_in_progress()
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| {
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|     return CMOS::read(0x0a) & 0x80;
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| }
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| 
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| static u8 bcd_to_binary(u8 bcd)
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| {
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|     return (bcd & 0x0F) + ((bcd >> 4) * 10);
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| }
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| 
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| void read_registers(unsigned& year, unsigned& month, unsigned& day, unsigned& hour, unsigned& minute, unsigned& second)
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| {
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|     while (update_in_progress())
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|         ;
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| 
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|     u8 status_b = CMOS::read(0x0b);
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| 
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|     second = CMOS::read(0x00);
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|     minute = CMOS::read(0x02);
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|     hour = CMOS::read(0x04);
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|     day = CMOS::read(0x07);
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|     month = CMOS::read(0x08);
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|     year = CMOS::read(0x09);
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| 
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|     bool is_pm = hour & 0x80;
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| 
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|     if (!(status_b & 0x04)) {
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|         second = bcd_to_binary(second);
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|         minute = bcd_to_binary(minute);
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|         hour = bcd_to_binary(hour & 0x7F);
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|         day = bcd_to_binary(day);
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|         month = bcd_to_binary(month);
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|         year = bcd_to_binary(year);
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|     }
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| 
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|     if (!(status_b & 0x02)) {
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|         // In the 12 hour clock, midnight and noon are 12, not 0. Map it to 0.
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|         hour %= 12;
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|         if (is_pm)
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|             hour += 12;
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|     }
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| 
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|     year += 2000;
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| }
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| 
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| time_t now()
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| {
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|     // FIXME: We should probably do something more robust here.
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|     //        Perhaps read all the values twice and verify that they were identical.
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|     //        We don't want to be caught in the middle of an RTC register update.
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|     while (update_in_progress())
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|         ;
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| 
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|     unsigned year, month, day, hour, minute, second;
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|     read_registers(year, month, day, hour, minute, second);
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| 
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|     dmesgln("RTC: Year: {}, month: {}, day: {}, hour: {}, minute: {}, second: {}", year, month, day, hour, minute, second);
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| 
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|     time_t days_since_epoch = years_to_days_since_epoch(year) + day_of_year(year, month, day);
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|     return ((days_since_epoch * 24 + hour) * 60 + minute) * 60 + second;
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| }
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| 
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| }
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