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 "kernel/proc.h"
  10 #include "proto.h"
  11 #include <minix/portio.h>
  12 #include <machine/cpu.h>
  13
  14 #define ICW1_AT         0x11    /* edge triggered, cascade, need ICW4 */
  15 #define ICW1_PC         0x13    /* edge triggered, no cascade, need ICW4 */
  16 #define ICW1_PS         0x19    /* level triggered, cascade, need ICW4 */
  17 #define ICW4_AT_SLAVE   0x01    /* not SFNM, not buffered, normal EOI, 8086 */
  18 #define ICW4_AT_MASTER  0x05    /* not SFNM, not buffered, normal EOI, 8086 */
  19 #define ICW4_PC_SLAVE   0x09    /* not SFNM, buffered, normal EOI, 8086 */
  20 #define ICW4_PC_MASTER  0x0D    /* not SFNM, buffered, normal EOI, 8086 */
  21 #define ICW4_AT_AEOI_SLAVE   0x03 /* not SFNM, not buffered, auto EOI, 8086 */
  22 #define ICW4_AT_AEOI_MASTER  0x07 /* not SFNM, not buffered, auto EOI, 8086 */
  23 #define ICW4_PC_AEOI_SLAVE   0x0B /* not SFNM, buffered, auto EOI, 8086 */
  24 #define ICW4_PC_AEOI_MASTER  0x0F /* not SFNM, buffered, auto EOI, 8086 */
  25
  26 /*===========================================================================*
  27  *                              intr_init                                    *
  28  *===========================================================================*/
  29 PUBLIC int intr_init(const int mine, const int auto_eoi)
  30 {
  31 /* Initialize the 8259s, finishing with all interrupts disabled.  This is
  32  * only done in protected mode, in real mode we don't touch the 8259s, but
  33  * use the BIOS locations instead.  The flag "mine" is set if the 8259s are
  34  * to be programmed for MINIX, or to be reset to what the BIOS expects.
  35  */
  36
  37       /* The AT and newer PS/2 have two interrupt controllers, one master,
  38        * one slaved at IRQ 2.  (We don't have to deal with the PC that
  39        * has just one controller, because it must run in real mode.)
  40        */
  41       outb( INT_CTL, machine.ps_mca ? ICW1_PS : ICW1_AT);
  42       outb( INT_CTLMASK, mine == INTS_MINIX ? IRQ0_VECTOR : BIOS_IRQ0_VEC);
  43                                         /* ICW2 for master */
  44       outb( INT_CTLMASK, (1 << CASCADE_IRQ));
  45                                         /* ICW3 tells slaves */
  46       if (auto_eoi)
  47           outb( INT_CTLMASK, ICW4_AT_AEOI_MASTER);
  48       else
  49           outb( INT_CTLMASK, ICW4_AT_MASTER);
  50       outb( INT_CTLMASK, ~(1 << CASCADE_IRQ)); /* IRQ 0-7 mask */
  51       outb( INT2_CTL, machine.ps_mca ? ICW1_PS : ICW1_AT);
  52       outb( INT2_CTLMASK, mine == INTS_MINIX ? IRQ8_VECTOR : BIOS_IRQ8_VEC);
  53                                                 /* ICW2 for slave */
  54       outb( INT2_CTLMASK, CASCADE_IRQ); /* ICW3 is slave nr */
  55       if (auto_eoi)
  56          outb( INT2_CTLMASK, ICW4_AT_AEOI_SLAVE);
  57       else
  58          outb( INT2_CTLMASK, ICW4_AT_SLAVE);
  59       outb( INT2_CTLMASK, ~0);          /* IRQ 8-15 mask */
  60
  61       /* Copy the BIOS vectors from the BIOS to the Minix location, so we
  62        * can still make BIOS calls without reprogramming the i8259s.
  63        */
  64 #if IRQ0_VECTOR != BIOS_IRQ0_VEC
  65       phys_copy(BIOS_VECTOR(0) * 4L, VECTOR(0) * 4L, 8 * 4L);
  66 #endif
  67 #if IRQ8_VECTOR != BIOS_IRQ8_VEC
  68       phys_copy(BIOS_VECTOR(8) * 4L, VECTOR(8) * 4L, 8 * 4L);
  69 #endif
  70
  71   return OK;
  72 }
  73
  74 PUBLIC void irq_8259_unmask(const int irq)
  75 {
  76         const unsigned ctl_mask = irq < 8 ? INT_CTLMASK : INT2_CTLMASK;
  77         outb(ctl_mask, inb(ctl_mask) & ~(1 << (irq & 0x7)));
  78 }
  79
  80 PUBLIC void irq_8259_mask(const int irq)
  81 {
  82         const unsigned ctl_mask = irq < 8 ? INT_CTLMASK : INT2_CTLMASK;
  83         outb(ctl_mask, inb(ctl_mask) | (1 << (irq & 0x7)));
  84 }
  85
  86 /* Disable 8259 - write 0xFF in OCW1 master and slave. */
  87 PRIVATE void i8259_disable(void)
  88 {
  89         outb(INT2_CTLMASK, 0xFF);
  90         outb(INT_CTLMASK, 0xFF);
  91         inb(INT_CTLMASK);
  92 }
  93