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			70 lines
		
	
	
	
		
			2.2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			70 lines
		
	
	
	
		
			2.2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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|  * All rights reserved.
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|  *
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|  * Redistribution and use in source and binary forms, with or without
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|  * modification, are permitted provided that the following conditions are met:
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|  *
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|  * 1. Redistributions of source code must retain the above copyright notice, this
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|  *    list of conditions and the following disclaimer.
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|  *
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|  * 2. Redistributions in binary form must reproduce the above copyright notice,
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|  *    this list of conditions and the following disclaimer in the documentation
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|  *    and/or other materials provided with the distribution.
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|  *
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|  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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|  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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|  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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|  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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|  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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|  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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|  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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|  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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|  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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|  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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|  */
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| 
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| #pragma once
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| 
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| #include <AK/Types.h>
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| #include <Kernel/Devices/HardwareTimer.h>
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| 
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| namespace Kernel {
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| 
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| #define TICKS_PER_SECOND 1000
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| /* Timer related ports */
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| #define TIMER0_CTL 0x40
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| #define TIMER1_CTL 0x41
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| #define TIMER2_CTL 0x42
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| #define PIT_CTL 0x43
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| 
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| /* Building blocks for PIT_CTL */
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| #define TIMER0_SELECT 0x00
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| #define TIMER1_SELECT 0x40
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| #define TIMER2_SELECT 0x80
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| 
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| #define MODE_COUNTDOWN 0x00
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| #define MODE_ONESHOT 0x02
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| #define MODE_RATE 0x04
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| #define MODE_SQUARE_WAVE 0x06
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| 
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| #define WRITE_WORD 0x30
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| 
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| #define BASE_FREQUENCY 1193182
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| 
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| class PIT : public HardwareTimer {
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| public:
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|     static void initialize();
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|     static PIT& the();
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|     u32 ticks_this_second() const;
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| 
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| private:
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|     PIT();
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|     // ^IRQHandler
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|     virtual void handle_irq(RegisterState& regs) override;
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| 
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|     u16 m_default_timer_reload;
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|     u16 m_variable_timer_reload;
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|     u32 m_ticks_this_second;
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| };
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| }
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