Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * proc_devtree.c - handles /proc/device-tree
3 *
4 * Copyright 1997 Paul Mackerras
5 */
6#include <linux/errno.h>
7#include <linux/time.h>
8#include <linux/proc_fs.h>
9#include <linux/stat.h>
10#include <linux/string.h>
11#include <asm/prom.h>
12#include <asm/uaccess.h>
13
14#ifndef HAVE_ARCH_DEVTREE_FIXUPS
15static inline void set_node_proc_entry(struct device_node *np,
16 struct proc_dir_entry *de)
17{
18}
19#endif
20
21static struct proc_dir_entry *proc_device_tree;
22
23/*
24 * Supply data on a read from /proc/device-tree/node/property.
25 */
26static int property_read_proc(char *page, char **start, off_t off,
27 int count, int *eof, void *data)
28{
29 struct property *pp = data;
30 int n;
31
32 if (off >= pp->length) {
33 *eof = 1;
34 return 0;
35 }
36 n = pp->length - off;
37 if (n > count)
38 n = count;
39 else
40 *eof = 1;
41 memcpy(page, pp->value + off, n);
42 *start = page;
43 return n;
44}
45
46/*
47 * For a node with a name like "gc@10", we make symlinks called "gc"
48 * and "@10" to it.
49 */
50
51/*
52 * Add a property to a node
53 */
54static struct proc_dir_entry *
55__proc_device_tree_add_prop(struct proc_dir_entry *de, struct property *pp)
56{
57 struct proc_dir_entry *ent;
58
59 /*
60 * Unfortunately proc_register puts each new entry
61 * at the beginning of the list. So we rearrange them.
62 */
63 ent = create_proc_read_entry(pp->name,
64 strncmp(pp->name, "security-", 9)
65 ? S_IRUGO : S_IRUSR, de,
66 property_read_proc, pp);
67 if (ent == NULL)
68 return NULL;
69
70 if (!strncmp(pp->name, "security-", 9))
71 ent->size = 0; /* don't leak number of password chars */
72 else
73 ent->size = pp->length;
74
75 return ent;
76}
77
78
79void proc_device_tree_add_prop(struct proc_dir_entry *pde, struct property *prop)
80{
81 __proc_device_tree_add_prop(pde, prop);
82}
83
84/*
85 * Process a node, adding entries for its children and its properties.
86 */
87void proc_device_tree_add_node(struct device_node *np,
88 struct proc_dir_entry *de)
89{
90 struct property *pp;
91 struct proc_dir_entry *ent;
92 struct device_node *child;
93 const char *p;
94
95 set_node_proc_entry(np, de);
96 for (child = NULL; (child = of_get_next_child(np, child));) {
97 p = strrchr(child->full_name, '/');
98 if (!p)
99 p = child->full_name;
100 else
101 ++p;
102 ent = proc_mkdir(p, de);
103 if (ent == 0)
104 break;
105 proc_device_tree_add_node(child, ent);
106 }
107 of_node_put(child);
108 for (pp = np->properties; pp != 0; pp = pp->next) {
109 /*
110 * Yet another Apple device-tree bogosity: on some machines,
111 * they have properties & nodes with the same name. Those
112 * properties are quite unimportant for us though, thus we
113 * simply "skip" them here, but we do have to check.
114 */
115 for (ent = de->subdir; ent != NULL; ent = ent->next)
116 if (!strcmp(ent->name, pp->name))
117 break;
118 if (ent != NULL) {
119 printk(KERN_WARNING "device-tree: property \"%s\" name"
120 " conflicts with node in %s\n", pp->name,
121 np->full_name);
122 continue;
123 }
124
125 ent = __proc_device_tree_add_prop(de, pp);
126 if (ent == 0)
127 break;
128 }
129}
130
131/*
132 * Called on initialization to set up the /proc/device-tree subtree
133 */
134void proc_device_tree_init(void)
135{
136 struct device_node *root;
137 if ( !have_of )
138 return;
139 proc_device_tree = proc_mkdir("device-tree", NULL);
140 if (proc_device_tree == 0)
141 return;
142 root = of_find_node_by_path("/");
143 if (root == 0) {
144 printk(KERN_ERR "/proc/device-tree: can't find root\n");
145 return;
146 }
147 proc_device_tree_add_node(root, proc_device_tree);
148 of_node_put(root);
149}