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  */
18 struct 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 
45 int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
46 			struct of_drc_info *data)
47 {
48 	const char *p;
49 	const __be32 *p2;
50 
51 	if (!data)
52 		return -EINVAL;
53 
54 	/* Get drc-type:encode-string */
55 	p = data->drc_type = (char*) (*curval);
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 	p2 = of_prop_next_u32(*prop, p2, &data->drc_index_start);
69 	if (!p2)
70 		return -EINVAL;
71 
72 	/* Get drc-name-suffix-start:encode-int */
73 	p2 = of_prop_next_u32(*prop, p2, &data->drc_name_suffix_start);
74 	if (!p2)
75 		return -EINVAL;
76 
77 	/* Get number-sequential-elements:encode-int */
78 	p2 = of_prop_next_u32(*prop, p2, &data->num_sequential_elems);
79 	if (!p2)
80 		return -EINVAL;
81 
82 	/* Get sequential-increment:encode-int */
83 	p2 = of_prop_next_u32(*prop, p2, &data->sequential_inc);
84 	if (!p2)
85 		return -EINVAL;
86 
87 	/* Get drc-power-domain:encode-int */
88 	p2 = of_prop_next_u32(*prop, p2, &data->drc_power_domain);
89 	if (!p2)
90 		return -EINVAL;
91 
92 	/* Should now know end of current entry */
93 	(*curval) = (void *)p2;
94 	data->last_drc_index = data->drc_index_start +
95 		((data->num_sequential_elems - 1) * data->sequential_inc);
96 
97 	return 0;
98 }
99 EXPORT_SYMBOL(of_read_drc_info_cell);
100