linux irq reference(mips)

Init hook:

trap_init:
set_except_vector(0, rollback ? rollback_handle_int : handle_int);

1)handle_level hook
arch_init_irq->init_nlm_common_irqs:
irq_set_chip_and_handler(i, &xlp_pic, handle_level_irq);
irq_set_chip_and_handler->irq_set_chip_and_handler_name->__irq_set_handler

__irq_set_handler:
desc->handle_irq = handle;

2)chip hook
irq_set_chip_and_handler(i, &xlp_pic, handle_level_irq);

3)special hook
request_irq->request_threaded_irq->__setup_irq(irq, desc, action);

__setup_irq:
/* add new interrupt at end of irq queue */
do {
    /*
     * Or all existing action->thread_mask bits,
     * so we can find the next zero bit for this
     * new action.
     */
    thread_mask |= old->thread_mask;
    old_ptr = &old->next;
    old = *old_ptr;
} while (old);

new->irq = irq;
*old_ptr = new;

Call tree:
(genex.s)handle_int->plat_irq_dispatch->do_IRQ->generic_handle_irq->(desc->handle_irq)
   
1) irqchip handle:     handle_level_irq->mask_ack_irq->(desc->irq_data.chip->irq_ack)

2) special irq handle :handle_level_irq->handle_irq_event->handle_irq_event_percpu->(action->handler)