int of_dma_get_range()

in address.c [931:997]

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

int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map)
{
	struct device_node *node = of_node_get(np);
	const __be32 *ranges = NULL;
	bool found_dma_ranges = false;
	struct of_range_parser parser;
	struct of_range range;
	struct bus_dma_region *r;
	int len, num_ranges = 0;
	int ret = 0;

	while (node) {
		ranges = of_get_property(node, "dma-ranges", &len);

		/* Ignore empty ranges, they imply no translation required */
		if (ranges && len > 0)
			break;

		/* Once we find 'dma-ranges', then a missing one is an error */
		if (found_dma_ranges && !ranges) {
			ret = -ENODEV;
			goto out;
		}
		found_dma_ranges = true;

		node = of_get_next_dma_parent(node);
	}

	if (!node || !ranges) {
		pr_debug("no dma-ranges found for node(%pOF)\n", np);
		ret = -ENODEV;
		goto out;
	}

	of_dma_range_parser_init(&parser, node);
	for_each_of_range(&parser, &range)
		num_ranges++;

	r = kcalloc(num_ranges + 1, sizeof(*r), GFP_KERNEL);
	if (!r) {
		ret = -ENOMEM;
		goto out;
	}

	/*
	 * Record all info in the generic DMA ranges array for struct device.
	 */
	*map = r;
	of_dma_range_parser_init(&parser, node);
	for_each_of_range(&parser, &range) {
		pr_debug("dma_addr(%llx) cpu_addr(%llx) size(%llx)\n",
			 range.bus_addr, range.cpu_addr, range.size);
		if (range.cpu_addr == OF_BAD_ADDR) {
			pr_err("translation of DMA address(%llx) to CPU address failed node(%pOF)\n",
			       range.bus_addr, node);
			continue;
		}
		r->cpu_start = range.cpu_addr;
		r->dma_start = range.bus_addr;
		r->size = range.size;
		r->offset = range.cpu_addr - range.bus_addr;
		r++;
	}
out:
	of_node_put(node);
	return ret;
}