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Serenity Operating System
1/*
2 * Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#pragma once
28
29#include <AK/NonnullRefPtr.h>
30#include <AK/Types.h>
31#include <Kernel/Time/HardwareTimer.h>
32
33namespace Kernel {
34
35/* Timer related ports */
36#define TIMER0_CTL 0x40
37#define TIMER1_CTL 0x41
38#define TIMER2_CTL 0x42
39#define PIT_CTL 0x43
40
41/* Building blocks for PIT_CTL */
42#define TIMER0_SELECT 0x00
43#define TIMER1_SELECT 0x40
44#define TIMER2_SELECT 0x80
45
46#define MODE_COUNTDOWN 0x00
47#define MODE_ONESHOT 0x02
48#define MODE_RATE 0x04
49#define MODE_SQUARE_WAVE 0x06
50
51#define WRITE_WORD 0x30
52
53#define BASE_FREQUENCY 1193182
54
55class PIT final : public HardwareTimer {
56public:
57 static NonnullRefPtr<PIT> initialize(Function<void(const RegisterState&)>);
58 virtual HardwareTimerType timer_type() const override { return HardwareTimerType::i8253; }
59 virtual const char* model() const override { return "i8254"; }
60 virtual size_t ticks_per_second() const override;
61
62 virtual bool is_periodic() const override { return m_periodic; }
63 virtual bool is_periodic_capable() const override { return true; }
64 virtual void set_periodic() override;
65 virtual void set_non_periodic() override;
66
67 virtual void reset_to_default_ticks_per_second() override;
68 virtual bool try_to_set_frequency(size_t frequency) override;
69 virtual bool is_capable_of_frequency(size_t frequency) const override;
70 virtual size_t calculate_nearest_possible_frequency(size_t frequency) const override;
71
72private:
73 explicit PIT(Function<void(const RegisterState&)>);
74 bool m_periodic { true };
75};
76}