70 lines
1.8 KiB
C
70 lines
1.8 KiB
C
/*
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* Basic support for controlling the 8259 Programmable Interrupt Controllers.
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*
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* Initially written by Michael Brown (mcb30).
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*/
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#ifndef PIC8259_H
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#define PIC8259_H
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/* For segoff_t */
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#include "realmode.h"
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#define IRQ_PIC_CUTOFF 8
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/* 8259 register locations */
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#define PIC1_ICW1 0x20
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#define PIC1_OCW2 0x20
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#define PIC1_OCW3 0x20
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#define PIC1_ICR 0x20
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#define PIC1_IRR 0x20
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#define PIC1_ISR 0x20
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#define PIC1_ICW2 0x21
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#define PIC1_ICW3 0x21
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#define PIC1_ICW4 0x21
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#define PIC1_IMR 0x21
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#define PIC2_ICW1 0xa0
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#define PIC2_OCW2 0xa0
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#define PIC2_OCW3 0xa0
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#define PIC2_ICR 0xa0
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#define PIC2_IRR 0xa0
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#define PIC2_ISR 0xa0
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#define PIC2_ICW2 0xa1
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#define PIC2_ICW3 0xa1
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#define PIC2_ICW4 0xa1
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#define PIC2_IMR 0xa1
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/* Register command values */
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#define OCW3_ID 0x08
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#define OCW3_READ_IRR 0x03
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#define OCW3_READ_ISR 0x02
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#define ICR_EOI_NON_SPECIFIC 0x20
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#define ICR_EOI_NOP 0x40
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#define ICR_EOI_SPECIFIC 0x60
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#define ICR_EOI_SET_PRIORITY 0xc0
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/* Macros to enable/disable IRQs */
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#define IMR_REG(x) ( (x) < IRQ_PIC_CUTOFF ? PIC1_IMR : PIC2_IMR )
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#define IMR_BIT(x) ( 1 << ( (x) % IRQ_PIC_CUTOFF ) )
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#define irq_enabled(x) ( ( inb ( IMR_REG(x) ) & IMR_BIT(x) ) == 0 )
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#define enable_irq(x) outb ( inb( IMR_REG(x) ) & ~IMR_BIT(x), IMR_REG(x) )
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#define disable_irq(x) outb ( inb( IMR_REG(x) ) | IMR_BIT(x), IMR_REG(x) )
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/* Macros for acknowledging IRQs */
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#define ICR_REG( irq ) ( (irq) < IRQ_PIC_CUTOFF ? PIC1_ICR : PIC2_ICR )
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#define ICR_VALUE( irq ) ( (irq) % IRQ_PIC_CUTOFF )
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#define CHAINED_IRQ 2
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/* Utility macros to convert IRQ numbers to INT numbers and INT vectors */
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#define IRQ_INT( irq ) ( ( ( (irq) - IRQ_PIC_CUTOFF ) ^ 0x70 ) & 0x7f )
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/* Other constants */
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#define IRQ_MAX 15
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#define IRQ_NONE -1U
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/* Function prototypes
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*/
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void send_eoi ( unsigned int irq );
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#endif /* PIC8259_H */
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