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