102 lines
1.7 KiB
C++
102 lines
1.7 KiB
C++
#include <kernel/IDT.h>
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#include <kernel/IO.h>
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#include <kernel/PIC.h>
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#include <string.h>
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#define PIC1_CMD 0x20
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#define PIC1_DATA 0x21
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#define PIC2_CMD 0xA0
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#define PIC2_DATA 0xA1
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#define PIC_ISR 0x0B
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#define PIC_EOI 0x20
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#define ICW1_ICW4 0x01
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#define ICW1_INIT 0x10
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#define ICW4_8086 0x01
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namespace Kernel
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{
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PIC* PIC::create()
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{
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mask_all();
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remap();
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return new PIC;
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}
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void PIC::remap()
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{
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uint8_t a1 = IO::inb(PIC1_DATA);
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uint8_t a2 = IO::inb(PIC2_DATA);
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// Start the initialization sequence (in cascade mode)
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IO::outb(PIC1_CMD, ICW1_INIT | ICW1_ICW4);
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IO::io_wait();
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IO::outb(PIC2_CMD, ICW1_INIT | ICW1_ICW4);
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IO::io_wait();
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// ICW2
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IO::outb(PIC1_DATA, IRQ_VECTOR_BASE);
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IO::io_wait();
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IO::outb(PIC2_DATA, IRQ_VECTOR_BASE + 0x08);
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IO::io_wait();
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// ICW3
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IO::outb(PIC1_DATA, 4);
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IO::io_wait();
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IO::outb(PIC2_DATA, 2);
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IO::io_wait();
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// ICW4
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IO::outb(PIC1_DATA, ICW4_8086);
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IO::io_wait();
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IO::outb(PIC2_DATA, ICW4_8086);
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IO::io_wait();
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// Restore original masks
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IO::outb(PIC1_DATA, a1);
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IO::outb(PIC2_DATA, a2);
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}
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void PIC::mask_all()
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{
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// NOTE: don't mask irq 2 as it is needed for slave pic
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IO::outb(PIC1_DATA, 0xFB);
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IO::outb(PIC2_DATA, 0xFF);
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}
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void PIC::eoi(uint8_t irq)
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{
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if (irq >= 8)
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IO::outb(PIC2_CMD, PIC_EOI);
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IO::outb(PIC1_CMD, PIC_EOI);
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}
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void PIC::enable_irq(uint8_t irq)
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{
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uint16_t port = PIC1_DATA;
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if(irq >= 8)
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{
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port = PIC2_DATA;
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irq -= 8;
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}
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IO::outb(port, IO::inb(port) & ~(1 << irq));
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}
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bool PIC::is_in_service(uint8_t irq)
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{
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uint16_t port = PIC1_CMD;
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if (irq >= 8)
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{
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port = PIC2_CMD;
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irq -= 8;
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}
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IO::outb(port, PIC_ISR);
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return IO::inb(port) & (1 << irq);
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}
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}
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