1// SPDX-License-Identifier: GPL-2.0
2#include <linux/string.h>
3#include <linux/err.h>
4#include <linux/slab.h>
5#include <linux/of.h>
6#include <asm/prom.h>
7
8#include "of_helpers.h"
9
10/**
11 * pseries_of_derive_parent - basically like dirname(1)
12 * @path:  the full_name of a node to be added to the tree
13 *
14 * Returns the node which should be the parent of the node
15 * described by path.  E.g., for path = "/foo/bar", returns
16 * the node with full_name = "/foo".
17 */
18struct device_node *pseries_of_derive_parent(const char *path)
19{
20	struct device_node *parent;
21	char *parent_path = "/";
22	const char *tail;
23
24	/* We do not want the trailing '/' character */
25	tail = kbasename(path) - 1;
26
27	/* reject if path is "/" */
28	if (!strcmp(path, "/"))
29		return ERR_PTR(-EINVAL);
30
31	if (tail > path) {
32		parent_path = kstrndup(path, tail - path, GFP_KERNEL);
33		if (!parent_path)
34			return ERR_PTR(-ENOMEM);
35	}
36	parent = of_find_node_by_path(parent_path);
37	if (strcmp(parent_path, "/"))
38		kfree(parent_path);
39	return parent ? parent : ERR_PTR(-EINVAL);
40}
41
42
43/* Helper Routines to convert between drc_index to cpu numbers */
44
45int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
46			struct of_drc_info *data)
47{
48	const char *p = (char *)(*curval);
49	const __be32 *p2;
50
51	if (!data)
52		return -EINVAL;
53
54	/* Get drc-type:encode-string */
55	data->drc_type = (char *)p;
56	p = of_prop_next_string(*prop, p);
57	if (!p)
58		return -EINVAL;
59
60	/* Get drc-name-prefix:encode-string */
61	data->drc_name_prefix = (char *)p;
62	p = of_prop_next_string(*prop, p);
63	if (!p)
64		return -EINVAL;
65
66	/* Get drc-index-start:encode-int */
67	p2 = (const __be32 *)p;
68	data->drc_index_start = be32_to_cpu(*p2);
69
70	/* Get drc-name-suffix-start:encode-int */
71	p2 = of_prop_next_u32(*prop, p2, &data->drc_name_suffix_start);
72	if (!p2)
73		return -EINVAL;
74
75	/* Get number-sequential-elements:encode-int */
76	p2 = of_prop_next_u32(*prop, p2, &data->num_sequential_elems);
77	if (!p2)
78		return -EINVAL;
79
80	/* Get sequential-increment:encode-int */
81	p2 = of_prop_next_u32(*prop, p2, &data->sequential_inc);
82	if (!p2)
83		return -EINVAL;
84
85	/* Get drc-power-domain:encode-int */
86	p2 = of_prop_next_u32(*prop, p2, &data->drc_power_domain);
87	if (!p2)
88		return -EINVAL;
89
90	/* Should now know end of current entry */
91	(*curval) = (void *)(++p2);
92	data->last_drc_index = data->drc_index_start +
93		((data->num_sequential_elems - 1) * data->sequential_inc);
94
95	return 0;
96}
97EXPORT_SYMBOL(of_read_drc_info_cell);
98