minix/kernel/arch/i386/i8259.c

   1 /* This file contains routines for initializing the 8259 interrupt controller:
   2  *      put_irq_handler: register an interrupt handler
   3  *      rm_irq_handler: deregister an interrupt handler
   4  *      intr_handle:    handle a hardware interrupt
   5  *      intr_init:      initialize the interrupt controller(s)
   6  */
   7
   8 #include "kernel/kernel.h"
   9 #include "arch_proto.h"
  10 #include "hw_intr.h"
  11 #include <machine/cpu.h>
  12
  13 #define ICW1_AT         0x11    /* edge triggered, cascade, need ICW4 */
  14 #define ICW1_PC         0x13    /* edge triggered, no cascade, need ICW4 */
  15 #define ICW1_PS         0x19    /* level triggered, cascade, need ICW4 */
  16 #define ICW4_AT_SLAVE   0x01    /* not SFNM, not buffered, normal EOI, 8086 */
  17 #define ICW4_AT_MASTER  0x05    /* not SFNM, not buffered, normal EOI, 8086 */
  18 #define ICW4_PC_SLAVE   0x09    /* not SFNM, buffered, normal EOI, 8086 */
  19 #define ICW4_PC_MASTER  0x0D    /* not SFNM, buffered, normal EOI, 8086 */
  20 #define ICW4_AT_AEOI_SLAVE   0x03 /* not SFNM, not buffered, auto EOI, 8086 */
  21 #define ICW4_AT_AEOI_MASTER  0x07 /* not SFNM, not buffered, auto EOI, 8086 */
  22 #define ICW4_PC_AEOI_SLAVE   0x0B /* not SFNM, buffered, auto EOI, 8086 */
  23 #define ICW4_PC_AEOI_MASTER  0x0F /* not SFNM, buffered, auto EOI, 8086 */
  24
  25 /*===========================================================================*
  26  *                              intr_init                                    *
  27  *===========================================================================*/
  28 int intr_init(const int auto_eoi)
  29 {
  30 /* Initialize the 8259s, finishing with all interrupts disabled.  */
  31       outb( INT_CTL, ICW1_AT);
  32       outb( INT_CTLMASK, IRQ0_VECTOR);
  33                                         /* ICW2 for master */
  34       outb( INT_CTLMASK, (1 << CASCADE_IRQ));
  35                                         /* ICW3 tells slaves */
  36       if (auto_eoi)
  37           outb( INT_CTLMASK, ICW4_AT_AEOI_MASTER);
  38       else
  39           outb( INT_CTLMASK, ICW4_AT_MASTER);
  40       outb( INT_CTLMASK, ~(1 << CASCADE_IRQ)); /* IRQ 0-7 mask */
  41       outb( INT2_CTL, ICW1_AT);
  42       outb( INT2_CTLMASK, IRQ8_VECTOR);
  43                                                 /* ICW2 for slave */
  44       outb( INT2_CTLMASK, CASCADE_IRQ); /* ICW3 is slave nr */
  45       if (auto_eoi)
  46          outb( INT2_CTLMASK, ICW4_AT_AEOI_SLAVE);
  47       else
  48          outb( INT2_CTLMASK, ICW4_AT_SLAVE);
  49       outb( INT2_CTLMASK, ~0);          /* IRQ 8-15 mask */
  50
  51   return OK;
  52 }
  53
  54 void irq_8259_unmask(const int irq)
  55 {
  56         const unsigned ctl_mask = irq < 8 ? INT_CTLMASK : INT2_CTLMASK;
  57         outb(ctl_mask, inb(ctl_mask) & ~(1 << (irq & 0x7)));
  58 }
  59
  60 void irq_8259_mask(const int irq)
  61 {
  62         const unsigned ctl_mask = irq < 8 ? INT_CTLMASK : INT2_CTLMASK;
  63         outb(ctl_mask, inb(ctl_mask) | (1 << (irq & 0x7)));
  64 }
  65
  66 /* Disable 8259 - write 0xFF in OCW1 master and slave. */
  67 void i8259_disable(void)
  68 {
  69         outb(INT2_CTLMASK, 0xFF);
  70         outb(INT_CTLMASK, 0xFF);
  71         inb(INT_CTLMASK);
  72 }
  73
  74 void irq_8259_eoi(int irq)
  75 {
  76         if (irq < 8)
  77                 eoi_8259_master();
  78         else
  79                 eoi_8259_slave();
  80 }