static irqreturn_t irq_handler()

in ohci.c [2058:2157]

• 71 lines of code
• 21 McCabe index (conditional complexity)

static irqreturn_t irq_handler(int irq, void *data)
{
	struct fw_ohci *ohci = data;
	u32 event, iso_event;
	int i;

	event = reg_read(ohci, OHCI1394_IntEventClear);

	if (!event || !~event)
		return IRQ_NONE;

	/*
	 * busReset and postedWriteErr must not be cleared yet
	 * (OHCI 1.1 clauses 7.2.3.2 and 13.2.8.1)
	 */
	reg_write(ohci, OHCI1394_IntEventClear,
		  event & ~(OHCI1394_busReset | OHCI1394_postedWriteErr));
	log_irqs(ohci, event);

	if (event & OHCI1394_selfIDComplete)
		queue_work(selfid_workqueue, &ohci->bus_reset_work);

	if (event & OHCI1394_RQPkt)
		tasklet_schedule(&ohci->ar_request_ctx.tasklet);

	if (event & OHCI1394_RSPkt)
		tasklet_schedule(&ohci->ar_response_ctx.tasklet);

	if (event & OHCI1394_reqTxComplete)
		tasklet_schedule(&ohci->at_request_ctx.tasklet);

	if (event & OHCI1394_respTxComplete)
		tasklet_schedule(&ohci->at_response_ctx.tasklet);

	if (event & OHCI1394_isochRx) {
		iso_event = reg_read(ohci, OHCI1394_IsoRecvIntEventClear);
		reg_write(ohci, OHCI1394_IsoRecvIntEventClear, iso_event);

		while (iso_event) {
			i = ffs(iso_event) - 1;
			tasklet_schedule(
				&ohci->ir_context_list[i].context.tasklet);
			iso_event &= ~(1 << i);
		}
	}

	if (event & OHCI1394_isochTx) {
		iso_event = reg_read(ohci, OHCI1394_IsoXmitIntEventClear);
		reg_write(ohci, OHCI1394_IsoXmitIntEventClear, iso_event);

		while (iso_event) {
			i = ffs(iso_event) - 1;
			tasklet_schedule(
				&ohci->it_context_list[i].context.tasklet);
			iso_event &= ~(1 << i);
		}
	}

	if (unlikely(event & OHCI1394_regAccessFail))
		ohci_err(ohci, "register access failure\n");

	if (unlikely(event & OHCI1394_postedWriteErr)) {
		reg_read(ohci, OHCI1394_PostedWriteAddressHi);
		reg_read(ohci, OHCI1394_PostedWriteAddressLo);
		reg_write(ohci, OHCI1394_IntEventClear,
			  OHCI1394_postedWriteErr);
		if (printk_ratelimit())
			ohci_err(ohci, "PCI posted write error\n");
	}

	if (unlikely(event & OHCI1394_cycleTooLong)) {
		if (printk_ratelimit())
			ohci_notice(ohci, "isochronous cycle too long\n");
		reg_write(ohci, OHCI1394_LinkControlSet,
			  OHCI1394_LinkControl_cycleMaster);
	}

	if (unlikely(event & OHCI1394_cycleInconsistent)) {
		/*
		 * We need to clear this event bit in order to make
		 * cycleMatch isochronous I/O work.  In theory we should
		 * stop active cycleMatch iso contexts now and restart
		 * them at least two cycles later.  (FIXME?)
		 */
		if (printk_ratelimit())
			ohci_notice(ohci, "isochronous cycle inconsistent\n");
	}

	if (unlikely(event & OHCI1394_unrecoverableError))
		handle_dead_contexts(ohci);

	if (event & OHCI1394_cycle64Seconds) {
		spin_lock(&ohci->lock);
		update_bus_time(ohci);
		spin_unlock(&ohci->lock);
	} else
		flush_writes(ohci);

	return IRQ_HANDLED;
}