int of_parse_phandle_with_args_map()

in base.c [1593:1732]

• 103 lines of code
• 24 McCabe index (conditional complexity)

int of_parse_phandle_with_args_map(const struct device_node *np,
				   const char *list_name,
				   const char *stem_name,
				   int index, struct of_phandle_args *out_args)
{
	char *cells_name, *map_name = NULL, *mask_name = NULL;
	char *pass_name = NULL;
	struct device_node *cur, *new = NULL;
	const __be32 *map, *mask, *pass;
	static const __be32 dummy_mask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
	static const __be32 dummy_pass[] = { [0 ... MAX_PHANDLE_ARGS] = 0 };
	__be32 initial_match_array[MAX_PHANDLE_ARGS];
	const __be32 *match_array = initial_match_array;
	int i, ret, map_len, match;
	u32 list_size, new_size;

	if (index < 0)
		return -EINVAL;

	cells_name = kasprintf(GFP_KERNEL, "#%s-cells", stem_name);
	if (!cells_name)
		return -ENOMEM;

	ret = -ENOMEM;
	map_name = kasprintf(GFP_KERNEL, "%s-map", stem_name);
	if (!map_name)
		goto free;

	mask_name = kasprintf(GFP_KERNEL, "%s-map-mask", stem_name);
	if (!mask_name)
		goto free;

	pass_name = kasprintf(GFP_KERNEL, "%s-map-pass-thru", stem_name);
	if (!pass_name)
		goto free;

	ret = __of_parse_phandle_with_args(np, list_name, cells_name, -1, index,
					   out_args);
	if (ret)
		goto free;

	/* Get the #<list>-cells property */
	cur = out_args->np;
	ret = of_property_read_u32(cur, cells_name, &list_size);
	if (ret < 0)
		goto put;

	/* Precalculate the match array - this simplifies match loop */
	for (i = 0; i < list_size; i++)
		initial_match_array[i] = cpu_to_be32(out_args->args[i]);

	ret = -EINVAL;
	while (cur) {
		/* Get the <list>-map property */
		map = of_get_property(cur, map_name, &map_len);
		if (!map) {
			ret = 0;
			goto free;
		}
		map_len /= sizeof(u32);

		/* Get the <list>-map-mask property (optional) */
		mask = of_get_property(cur, mask_name, NULL);
		if (!mask)
			mask = dummy_mask;
		/* Iterate through <list>-map property */
		match = 0;
		while (map_len > (list_size + 1) && !match) {
			/* Compare specifiers */
			match = 1;
			for (i = 0; i < list_size; i++, map_len--)
				match &= !((match_array[i] ^ *map++) & mask[i]);

			of_node_put(new);
			new = of_find_node_by_phandle(be32_to_cpup(map));
			map++;
			map_len--;

			/* Check if not found */
			if (!new)
				goto put;

			if (!of_device_is_available(new))
				match = 0;

			ret = of_property_read_u32(new, cells_name, &new_size);
			if (ret)
				goto put;

			/* Check for malformed properties */
			if (WARN_ON(new_size > MAX_PHANDLE_ARGS))
				goto put;
			if (map_len < new_size)
				goto put;

			/* Move forward by new node's #<list>-cells amount */
			map += new_size;
			map_len -= new_size;
		}
		if (!match)
			goto put;

		/* Get the <list>-map-pass-thru property (optional) */
		pass = of_get_property(cur, pass_name, NULL);
		if (!pass)
			pass = dummy_pass;

		/*
		 * Successfully parsed a <list>-map translation; copy new
		 * specifier into the out_args structure, keeping the
		 * bits specified in <list>-map-pass-thru.
		 */
		match_array = map - new_size;
		for (i = 0; i < new_size; i++) {
			__be32 val = *(map - new_size + i);

			if (i < list_size) {
				val &= ~pass[i];
				val |= cpu_to_be32(out_args->args[i]) & pass[i];
			}

			out_args->args[i] = be32_to_cpu(val);
		}
		out_args->args_count = list_size = new_size;
		/* Iterate again with new provider */
		out_args->np = new;
		of_node_put(cur);
		cur = new;
	}
put:
	of_node_put(cur);
	of_node_put(new);
free:
	kfree(mask_name);
	kfree(map_name);
	kfree(cells_name);
	kfree(pass_name);

	return ret;
}