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 = (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 }
97 EXPORT_SYMBOL(of_read_drc_info_cell);
98
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