mirror of
https://github.com/SerenityOS/serenity
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144 lines
3.8 KiB
C++
144 lines
3.8 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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#include <AK/Assertions.h>
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#include <AK/Types.h>
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#include <Kernel/Arch/i386/CPU.h>
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#include <Kernel/Arch/i386/PIC.h>
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#include <LibBareMetal/IO.h>
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namespace Kernel {
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// The slave 8259 is connected to the master's IRQ2 line.
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// This is really only to enhance clarity.
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#define SLAVE_INDEX 2
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#define PIC0_CTL 0x20
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#define PIC0_CMD 0x21
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#define PIC1_CTL 0xA0
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#define PIC1_CMD 0xA1
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#ifdef DEBUG_PIC
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static bool initialized;
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#endif
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namespace PIC {
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void disable(u8 irq)
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{
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InterruptDisabler disabler;
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u8 imr;
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if (irq & 8) {
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imr = IO::in8(PIC1_CMD);
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imr |= 1 << (irq - 8);
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IO::out8(PIC1_CMD, imr);
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} else {
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imr = IO::in8(PIC0_CMD);
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imr |= 1 << irq;
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IO::out8(PIC0_CMD, imr);
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}
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}
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void enable(u8 irq)
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{
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InterruptDisabler disabler;
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u8 imr;
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if (irq & 8) {
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imr = IO::in8(PIC1_CMD);
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imr &= ~(1 << (irq - 8));
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IO::out8(PIC1_CMD, imr);
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} else {
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imr = IO::in8(PIC0_CMD);
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imr &= ~(1 << irq);
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IO::out8(PIC0_CMD, imr);
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}
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}
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void eoi(u8 irq)
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{
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if (irq & 8)
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IO::out8(PIC1_CTL, 0x20);
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IO::out8(PIC0_CTL, 0x20);
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}
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void initialize()
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{
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#ifdef DEBUG_PIC
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ASSERT(!initialized);
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#endif
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/* ICW1 (edge triggered mode, cascading controllers, expect ICW4) */
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IO::out8(PIC0_CTL, 0x11);
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IO::out8(PIC1_CTL, 0x11);
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/* ICW2 (upper 5 bits specify ISR indices, lower 3 idunno) */
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IO::out8(PIC0_CMD, IRQ_VECTOR_BASE);
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IO::out8(PIC1_CMD, IRQ_VECTOR_BASE + 0x08);
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/* ICW3 (configure master/slave relationship) */
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IO::out8(PIC0_CMD, 1 << SLAVE_INDEX);
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IO::out8(PIC1_CMD, SLAVE_INDEX);
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/* ICW4 (set x86 mode) */
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IO::out8(PIC0_CMD, 0x01);
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IO::out8(PIC1_CMD, 0x01);
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// Mask -- start out with all IRQs disabled.
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IO::out8(PIC0_CMD, 0xff);
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IO::out8(PIC1_CMD, 0xff);
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// ...except IRQ2, since that's needed for the master to let through slave interrupts.
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enable(2);
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kprintf("PIC(i8259): cascading mode, vectors 0x%b-0x%b\n", IRQ_VECTOR_BASE, IRQ_VECTOR_BASE + 0x08);
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#ifdef DEBUG_PIC
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initialized = true;
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#endif
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}
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u16 get_isr()
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{
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IO::out8(PIC0_CTL, 0x0b);
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IO::out8(PIC1_CTL, 0x0b);
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u8 isr0 = IO::in8(PIC0_CTL);
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u8 isr1 = IO::in8(PIC1_CTL);
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return (isr1 << 8) | isr0;
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}
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u16 get_irr()
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{
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IO::out8(PIC0_CTL, 0x0a);
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IO::out8(PIC1_CTL, 0x0a);
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u8 irr0 = IO::in8(PIC0_CTL);
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u8 irr1 = IO::in8(PIC1_CTL);
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return (irr1 << 8) | irr0;
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}
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}
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}
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