irq.c

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#include <core/system.h>
#include <core/string.h>
#include <mm/mm.h>
#include <dev/irq.h>
#include <platform/virt.h>
#include <aquila/errno.h>
 
MALLOC_DEFINE(M_IRQ, "irq", "IRQ handler");

struct handler {
    irq_handler_t fn;
    void *arg;
    struct handler *next;
};
 
/* Each interrupt's handlers, and how many times it came. */
static struct handler *handlers[IRQ_NR];
static uint64_t counts[IRQ_NR];
 
/*
 * Installs a handler for an interrupt.
 */
int irq_install(unsigned irq, irq_handler_t fn, void *arg)
{
    if (irq >= IRQ_NR)
        return -EINVAL;
 
    struct handler *h = kmalloc(sizeof(*h), &M_IRQ, M_ZERO);
 
    if (!h)
        return -ENOMEM;
 
    h->fn  = fn;
    h->arg = arg;
 
    int first = !handlers[irq];
    struct handler **p = &handlers[irq];
 
    while (*p)
        p = &(*p)->next;
 
    *p = h;
 
    if (first)
        gic_enable(irq);
 
    return 0;
}
 
/*
 * Uninstalls a handler that irq_install() installed.
 */
void irq_uninstall(unsigned irq, irq_handler_t fn, void *arg)
{
    if (irq >= IRQ_NR)
        return;
 
    for (struct handler **p = &handlers[irq]; *p; p = &(*p)->next) {
        struct handler *h = *p;
 
        if (h->fn == fn && h->arg == arg) {
            *p = h->next;
            kfree(h);
            break;
        }
    }
 
    if (!handlers[irq])
        gic_disable(irq);
}

void irq_handle(void)
{
    unsigned irq = gic_ack();
 
    if (irq >= 1020)    /* a spurious interrupt: there's none */
        return;
 
    if (irq < IRQ_NR) {
        counts[irq]++;
 
        for (struct handler *h = handlers[irq]; h; h = h->next)
            h->fn(h->arg);
    }
 
    gic_eoi(irq);
}
 
/*
 * Writes `/proc/interrupts`: the controller, and how many times each
 * interrupt came.
 */
int arch_interrupts_info(char *buf, size_t size)
{
    int sz = snprintf(buf, size, "controller: gicv2\n");
 
    for (unsigned i = 0; i < IRQ_NR && (size_t) sz < size; ++i)
        if (counts[i])
            sz += snprintf(buf + sz, size - sz, "%d: %ld\n", i, counts[i]);
 
    return sz;
}