Linux kernel mirror (for testing)
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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 const char *name)
57{
58 struct proc_dir_entry *ent;
59
60 /*
61 * Unfortunately proc_register puts each new entry
62 * at the beginning of the list. So we rearrange them.
63 */
64 ent = create_proc_read_entry(name,
65 strncmp(name, "security-", 9)
66 ? S_IRUGO : S_IRUSR, de,
67 property_read_proc, pp);
68 if (ent == NULL)
69 return NULL;
70
71 if (!strncmp(name, "security-", 9))
72 ent->size = 0; /* don't leak number of password chars */
73 else
74 ent->size = pp->length;
75
76 return ent;
77}
78
79
80void proc_device_tree_add_prop(struct proc_dir_entry *pde, struct property *prop)
81{
82 __proc_device_tree_add_prop(pde, prop, prop->name);
83}
84
85void proc_device_tree_remove_prop(struct proc_dir_entry *pde,
86 struct property *prop)
87{
88 remove_proc_entry(prop->name, pde);
89}
90
91void proc_device_tree_update_prop(struct proc_dir_entry *pde,
92 struct property *newprop,
93 struct property *oldprop)
94{
95 struct proc_dir_entry *ent;
96
97 for (ent = pde->subdir; ent != NULL; ent = ent->next)
98 if (ent->data == oldprop)
99 break;
100 if (ent == NULL) {
101 printk(KERN_WARNING "device-tree: property \"%s\" "
102 " does not exist\n", oldprop->name);
103 } else {
104 ent->data = newprop;
105 ent->size = newprop->length;
106 }
107}
108
109/*
110 * Various dodgy firmware might give us nodes and/or properties with
111 * conflicting names. That's generally ok, except for exporting via /proc,
112 * so munge names here to ensure they're unique.
113 */
114
115static int duplicate_name(struct proc_dir_entry *de, const char *name)
116{
117 struct proc_dir_entry *ent;
118 int found = 0;
119
120 spin_lock(&proc_subdir_lock);
121
122 for (ent = de->subdir; ent != NULL; ent = ent->next) {
123 if (strcmp(ent->name, name) == 0) {
124 found = 1;
125 break;
126 }
127 }
128
129 spin_unlock(&proc_subdir_lock);
130
131 return found;
132}
133
134static const char *fixup_name(struct device_node *np, struct proc_dir_entry *de,
135 const char *name)
136{
137 char *fixed_name;
138 int fixup_len = strlen(name) + 2 + 1; /* name + #x + \0 */
139 int i = 1, size;
140
141realloc:
142 fixed_name = kmalloc(fixup_len, GFP_KERNEL);
143 if (fixed_name == NULL) {
144 printk(KERN_ERR "device-tree: Out of memory trying to fixup "
145 "name \"%s\"\n", name);
146 return name;
147 }
148
149retry:
150 size = snprintf(fixed_name, fixup_len, "%s#%d", name, i);
151 size++; /* account for NULL */
152
153 if (size > fixup_len) {
154 /* We ran out of space, free and reallocate. */
155 kfree(fixed_name);
156 fixup_len = size;
157 goto realloc;
158 }
159
160 if (duplicate_name(de, fixed_name)) {
161 /* Multiple duplicates. Retry with a different offset. */
162 i++;
163 goto retry;
164 }
165
166 printk(KERN_WARNING "device-tree: Duplicate name in %s, "
167 "renamed to \"%s\"\n", np->full_name, fixed_name);
168
169 return fixed_name;
170}
171
172/*
173 * Process a node, adding entries for its children and its properties.
174 */
175void proc_device_tree_add_node(struct device_node *np,
176 struct proc_dir_entry *de)
177{
178 struct property *pp;
179 struct proc_dir_entry *ent;
180 struct device_node *child;
181 const char *p;
182
183 set_node_proc_entry(np, de);
184 for (child = NULL; (child = of_get_next_child(np, child));) {
185 /* Use everything after the last slash, or the full name */
186 p = strrchr(child->full_name, '/');
187 if (!p)
188 p = child->full_name;
189 else
190 ++p;
191
192 if (duplicate_name(de, p))
193 p = fixup_name(np, de, p);
194
195 ent = proc_mkdir(p, de);
196 if (ent == 0)
197 break;
198 proc_device_tree_add_node(child, ent);
199 }
200 of_node_put(child);
201
202 for (pp = np->properties; pp != 0; pp = pp->next) {
203 p = pp->name;
204
205 if (duplicate_name(de, p))
206 p = fixup_name(np, de, p);
207
208 ent = __proc_device_tree_add_prop(de, pp, p);
209 if (ent == 0)
210 break;
211 }
212}
213
214/*
215 * Called on initialization to set up the /proc/device-tree subtree
216 */
217void proc_device_tree_init(void)
218{
219 struct device_node *root;
220 if ( !have_of )
221 return;
222 proc_device_tree = proc_mkdir("device-tree", NULL);
223 if (proc_device_tree == 0)
224 return;
225 root = of_find_node_by_path("/");
226 if (root == 0) {
227 printk(KERN_ERR "/proc/device-tree: can't find root\n");
228 return;
229 }
230 proc_device_tree_add_node(root, proc_device_tree);
231 of_node_put(root);
232}