97 lines
2.8 KiB
C
97 lines
2.8 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(x) ( (x) < IRQ_PIC_CUTOFF ? PIC1_ICR : PIC2_ICR )
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#define ICR_VALUE(x) ( (x) % 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(x) ( (x)<IRQ_PIC_CUTOFF ? (x)+0x08 : (x)-IRQ_PIC_CUTOFF+0x70 )
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#define INT_VECTOR(x) ( (segoff_t*) phys_to_virt( 4 * (x) ) )
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#define IRQ_VECTOR(x) ( INT_VECTOR ( IRQ_INT(x) ) )
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/* Other constants */
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typedef uint8_t irq_t;
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#define IRQ_MAX (15)
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#define IRQ_NONE (0xff)
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/* Function prototypes
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*/
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int install_irq_handler ( irq_t irq, segoff_t *handler,
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uint8_t *previously_enabled,
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segoff_t *previous_handler );
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int remove_irq_handler ( irq_t irq, segoff_t *handler,
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uint8_t *previously_enabled,
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segoff_t *previous_handler );
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int install_trivial_irq_handler ( irq_t irq );
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int remove_trivial_irq_handler ( irq_t irq );
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int trivial_irq_triggered ( irq_t irq );
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int copy_trivial_irq_handler ( void *target, size_t target_size );
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void send_non_specific_eoi ( irq_t irq );
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void send_specific_eoi ( irq_t irq );
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void fake_irq ( irq_t irq );
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#ifdef DEBUG_IRQ
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void dump_irq_status ( void );
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#else
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#define dump_irq_status()
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#endif
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/* Other code (e.g. undi.c) needs to know the size of the trivial IRQ
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* handler code, so we put prototypes and the size macro here.
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*/
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extern void _trivial_irq_handler ( void );
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extern char _trivial_irq_handler_size[];
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#define TRIVIAL_IRQ_HANDLER_SIZE FRAGMENT_SIZE(_trivial_irq_handler)
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#endif /* PIC8259_H */
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