src/arch/i386/include/pic8259.h

   1 /*
   2  * Basic support for controlling the 8259 Programmable Interrupt Controllers.
   3  *
   4  * Initially written by Michael Brown (mcb30).
   5  */
   6
   7 FILE_LICENCE ( GPL2_OR_LATER );
   8
   9 #ifndef PIC8259_H
  10 #define PIC8259_H
  11
  12 /* For segoff_t */
  13 #include "realmode.h"
  14
  15 #define IRQ_PIC_CUTOFF 8
  16
  17 /* 8259 register locations */
  18 #define PIC1_ICW1 0x20
  19 #define PIC1_OCW2 0x20
  20 #define PIC1_OCW3 0x20
  21 #define PIC1_ICR 0x20
  22 #define PIC1_IRR 0x20
  23 #define PIC1_ISR 0x20
  24 #define PIC1_ICW2 0x21
  25 #define PIC1_ICW3 0x21
  26 #define PIC1_ICW4 0x21
  27 #define PIC1_IMR 0x21
  28 #define PIC2_ICW1 0xa0
  29 #define PIC2_OCW2 0xa0
  30 #define PIC2_OCW3 0xa0
  31 #define PIC2_ICR 0xa0
  32 #define PIC2_IRR 0xa0
  33 #define PIC2_ISR 0xa0
  34 #define PIC2_ICW2 0xa1
  35 #define PIC2_ICW3 0xa1
  36 #define PIC2_ICW4 0xa1
  37 #define PIC2_IMR 0xa1
  38
  39 /* Register command values */
  40 #define OCW3_ID 0x08
  41 #define OCW3_READ_IRR 0x03
  42 #define OCW3_READ_ISR 0x02
  43 #define ICR_EOI_NON_SPECIFIC 0x20
  44 #define ICR_EOI_NOP 0x40
  45 #define ICR_EOI_SPECIFIC 0x60
  46 #define ICR_EOI_SET_PRIORITY 0xc0
  47
  48 /* Macros to enable/disable IRQs */
  49 #define IMR_REG(x) ( (x) < IRQ_PIC_CUTOFF ? PIC1_IMR : PIC2_IMR )
  50 #define IMR_BIT(x) ( 1 << ( (x) % IRQ_PIC_CUTOFF ) )
  51 #define irq_enabled(x) ( ( inb ( IMR_REG(x) ) & IMR_BIT(x) ) == 0 )
  52 #define enable_irq(x) outb ( inb( IMR_REG(x) ) & ~IMR_BIT(x), IMR_REG(x) )
  53 #define disable_irq(x) outb ( inb( IMR_REG(x) ) | IMR_BIT(x), IMR_REG(x) )
  54
  55 /* Macros for acknowledging IRQs */
  56 #define ICR_REG( irq ) ( (irq) < IRQ_PIC_CUTOFF ? PIC1_ICR : PIC2_ICR )
  57 #define ICR_VALUE( irq ) ( (irq) % IRQ_PIC_CUTOFF )
  58 #define CHAINED_IRQ 2
  59
  60 /* Utility macros to convert IRQ numbers to INT numbers and INT vectors  */
  61 #define IRQ_INT( irq ) ( ( ( (irq) - IRQ_PIC_CUTOFF ) ^ 0x70 ) & 0x7f )
  62
  63 /* Other constants */
  64 #define IRQ_MAX 15
  65 #define IRQ_NONE -1U
  66
  67 /* Function prototypes
  68  */
  69 void send_eoi ( unsigned int irq );
  70
  71 #endif /* PIC8259_H */