void __init of_irq_init()

in irq.c [522:620]

• 67 lines of code
• 10 McCabe index (conditional complexity)

void __init of_irq_init(const struct of_device_id *matches)
{
	const struct of_device_id *match;
	struct device_node *np, *parent = NULL;
	struct of_intc_desc *desc, *temp_desc;
	struct list_head intc_desc_list, intc_parent_list;

	INIT_LIST_HEAD(&intc_desc_list);
	INIT_LIST_HEAD(&intc_parent_list);

	for_each_matching_node_and_match(np, matches, &match) {
		if (!of_property_read_bool(np, "interrupt-controller") ||
				!of_device_is_available(np))
			continue;

		if (WARN(!match->data, "of_irq_init: no init function for %s\n",
			 match->compatible))
			continue;

		/*
		 * Here, we allocate and populate an of_intc_desc with the node
		 * pointer, interrupt-parent device_node etc.
		 */
		desc = kzalloc(sizeof(*desc), GFP_KERNEL);
		if (!desc) {
			of_node_put(np);
			goto err;
		}

		desc->irq_init_cb = match->data;
		desc->dev = of_node_get(np);
		desc->interrupt_parent = of_irq_find_parent(np);
		if (desc->interrupt_parent == np)
			desc->interrupt_parent = NULL;
		list_add_tail(&desc->list, &intc_desc_list);
	}

	/*
	 * The root irq controller is the one without an interrupt-parent.
	 * That one goes first, followed by the controllers that reference it,
	 * followed by the ones that reference the 2nd level controllers, etc.
	 */
	while (!list_empty(&intc_desc_list)) {
		/*
		 * Process all controllers with the current 'parent'.
		 * First pass will be looking for NULL as the parent.
		 * The assumption is that NULL parent means a root controller.
		 */
		list_for_each_entry_safe(desc, temp_desc, &intc_desc_list, list) {
			int ret;

			if (desc->interrupt_parent != parent)
				continue;

			list_del(&desc->list);

			of_node_set_flag(desc->dev, OF_POPULATED);

			pr_debug("of_irq_init: init %pOF (%p), parent %p\n",
				 desc->dev,
				 desc->dev, desc->interrupt_parent);
			ret = desc->irq_init_cb(desc->dev,
						desc->interrupt_parent);
			if (ret) {
				of_node_clear_flag(desc->dev, OF_POPULATED);
				kfree(desc);
				continue;
			}

			/*
			 * This one is now set up; add it to the parent list so
			 * its children can get processed in a subsequent pass.
			 */
			list_add_tail(&desc->list, &intc_parent_list);
		}

		/* Get the next pending parent that might have children */
		desc = list_first_entry_or_null(&intc_parent_list,
						typeof(*desc), list);
		if (!desc) {
			pr_err("of_irq_init: children remain, but no parents\n");
			break;
		}
		list_del(&desc->list);
		parent = desc->dev;
		kfree(desc);
	}

	list_for_each_entry_safe(desc, temp_desc, &intc_parent_list, list) {
		list_del(&desc->list);
		kfree(desc);
	}
err:
	list_for_each_entry_safe(desc, temp_desc, &intc_desc_list, list) {
		list_del(&desc->list);
		of_node_put(desc->dev);
		kfree(desc);
	}
}