int of_map_id()

in base.c [2285:2369]

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

int of_map_id(struct device_node *np, u32 id,
	       const char *map_name, const char *map_mask_name,
	       struct device_node **target, u32 *id_out)
{
	u32 map_mask, masked_id;
	int map_len;
	const __be32 *map = NULL;

	if (!np || !map_name || (!target && !id_out))
		return -EINVAL;

	map = of_get_property(np, map_name, &map_len);
	if (!map) {
		if (target)
			return -ENODEV;
		/* Otherwise, no map implies no translation */
		*id_out = id;
		return 0;
	}

	if (!map_len || map_len % (4 * sizeof(*map))) {
		pr_err("%pOF: Error: Bad %s length: %d\n", np,
			map_name, map_len);
		return -EINVAL;
	}

	/* The default is to select all bits. */
	map_mask = 0xffffffff;

	/*
	 * Can be overridden by "{iommu,msi}-map-mask" property.
	 * If of_property_read_u32() fails, the default is used.
	 */
	if (map_mask_name)
		of_property_read_u32(np, map_mask_name, &map_mask);

	masked_id = map_mask & id;
	for ( ; map_len > 0; map_len -= 4 * sizeof(*map), map += 4) {
		struct device_node *phandle_node;
		u32 id_base = be32_to_cpup(map + 0);
		u32 phandle = be32_to_cpup(map + 1);
		u32 out_base = be32_to_cpup(map + 2);
		u32 id_len = be32_to_cpup(map + 3);

		if (id_base & ~map_mask) {
			pr_err("%pOF: Invalid %s translation - %s-mask (0x%x) ignores id-base (0x%x)\n",
				np, map_name, map_name,
				map_mask, id_base);
			return -EFAULT;
		}

		if (masked_id < id_base || masked_id >= id_base + id_len)
			continue;

		phandle_node = of_find_node_by_phandle(phandle);
		if (!phandle_node)
			return -ENODEV;

		if (target) {
			if (*target)
				of_node_put(phandle_node);
			else
				*target = phandle_node;

			if (*target != phandle_node)
				continue;
		}

		if (id_out)
			*id_out = masked_id - id_base + out_base;

		pr_debug("%pOF: %s, using mask %08x, id-base: %08x, out-base: %08x, length: %08x, id: %08x -> %08x\n",
			np, map_name, map_mask, id_base, out_base,
			id_len, id, masked_id - id_base + out_base);
		return 0;
	}

	pr_info("%pOF: no %s translation for id 0x%x on %pOF\n", np, map_name,
		id, target && *target ? *target : NULL);

	/* Bypasses translation */
	if (id_out)
		*id_out = id;
	return 0;
}