minix/kernel/interrupt.c
Ben Gras c078ec0331 Basic VM and other minor improvements.
Not complete, probably not fully debugged or optimized.
2008-11-19 12:26:10 +00:00

141 lines
4 KiB
C

/*
* The Minix hardware interrupt system.
*
* This file contains routines for managing the interrupt
* controller.
*
* put_irq_handler: register an interrupt handler.
* rm_irq_handler: deregister an interrupt handler.
* intr_handle: handle a hardware interrupt.
* called by the system dependent part when an
* external interrupt occures.
* enable_irq: enable hook for IRQ.
* disable_irq: disable hook for IRQ.
*/
#include "kernel.h"
#include "proc.h"
#include <minix/com.h>
#include <archconst.h>
/* number of lists of IRQ hooks, one list per supported line. */
PUBLIC irq_hook_t* irq_handlers[NR_IRQ_VECTORS] = {0};
/*===========================================================================*
* put_irq_handler *
*===========================================================================*/
/* Register an interrupt handler. */
PUBLIC void put_irq_handler( irq_hook_t* hook, int irq, irq_handler_t handler)
{
int id;
irq_hook_t **line;
if( irq < 0 || irq >= NR_IRQ_VECTORS )
minix_panic("invalid call to put_irq_handler", irq);
line = &irq_handlers[irq];
id = 1;
while ( *line != NULL ) {
if(hook == *line) return; /* extra initialization */
line = &(*line)->next;
id <<= 1; /* max 32 hooks for one line. */
}
if(id == 0)
minix_panic("Too many handlers for irq", irq);
hook->next = NULL;
hook->handler = handler;
hook->irq = irq;
hook->id = id;
*line = hook;
irq_use |= 1 << irq; /* this does not work for irq >= 32 */
/* And as last enable the irq at the hardware.
*
* Internal this activates the line or source of the given interrupt.
*/
intr_unmask(hook);
}
/*===========================================================================*
* rm_irq_handler *
*===========================================================================*/
/* Unregister an interrupt handler. */
PUBLIC void rm_irq_handler( irq_hook_t* hook ) {
int irq = hook->irq;
int id = hook->id;
irq_hook_t **line;
if( irq < 0 || irq >= NR_IRQ_VECTORS )
minix_panic("invalid call to rm_irq_handler", irq);
/* disable the irq. */
intr_mask(hook);
/* remove the hook. */
line = &irq_handlers[irq];
while( (*line) != NULL ) {
if((*line)->id == id) {
(*line) = (*line)->next;
if(!irq_handlers[irq])
irq_use &= ~(1 << irq);
return;
}
line = &(*line)->next;
}
/* When the handler is not found, normally return here. */
}
/*===========================================================================*
* intr_handle *
*===========================================================================*/
PUBLIC void intr_handle(irq_hook_t *hook)
{
/* Call the interrupt handlers for an interrupt with the given hook list.
* The assembly part of the handler has already masked the IRQ, reenabled the
* controller(s) and enabled interrupts.
*/
/* Call list of handlers for an IRQ. */
while( hook != NULL ) {
/* For each handler in the list, mark it active by setting its ID bit,
* call the function, and unmark it if the function returns true.
*/
irq_actids[hook->irq] |= hook->id;
/* Call the hooked function. */
if( (*hook->handler)(hook) )
irq_actids[hook->irq] &= ~hook->id;
/* Next hooked function. */
hook = hook->next;
}
/* The assembly code will now disable interrupts, unmask the IRQ if and only
* if all active ID bits are cleared, and restart a process.
*/
}
/* Enable/Disable a interrupt line. */
PUBLIC void enable_irq(hook)
irq_hook_t* hook;
{
if((irq_actids[hook->irq] &= ~hook->id) == 0) {
intr_unmask(hook);
return;
}
}
/* Return true if the interrupt was enabled before call. */
PUBLIC int disable_irq(hook)
irq_hook_t* hook;
{
if(irq_actids[hook->irq] & hook->id) /* already disabled */
return 0;
irq_actids[hook->irq] |= hook->id;
intr_mask(hook);
return TRUE;
}