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1/*
2 * proc_devtree.c - handles /proc/device-tree
3 *
4 * Copyright 1997 Paul Mackerras
5 */
6#include <linux/errno.h>
7#include <linux/init.h>
8#include <linux/time.h>
9#include <linux/proc_fs.h>
10#include <linux/seq_file.h>
11#include <linux/stat.h>
12#include <linux/string.h>
13#include <linux/of.h>
14#include <linux/module.h>
15#include <linux/slab.h>
16#include <asm/prom.h>
17#include <asm/uaccess.h>
18#include "internal.h"
19
20static inline void set_node_proc_entry(struct device_node *np,
21 struct proc_dir_entry *de)
22{
23#ifdef HAVE_ARCH_DEVTREE_FIXUPS
24 np->pde = de;
25#endif
26}
27
28static struct proc_dir_entry *proc_device_tree;
29
30/*
31 * Supply data on a read from /proc/device-tree/node/property.
32 */
33static int property_proc_show(struct seq_file *m, void *v)
34{
35 struct property *pp = m->private;
36
37 seq_write(m, pp->value, pp->length);
38 return 0;
39}
40
41static int property_proc_open(struct inode *inode, struct file *file)
42{
43 return single_open(file, property_proc_show, PDE(inode)->data);
44}
45
46static const struct file_operations property_proc_fops = {
47 .owner = THIS_MODULE,
48 .open = property_proc_open,
49 .read = seq_read,
50 .llseek = seq_lseek,
51 .release = single_release,
52};
53
54/*
55 * For a node with a name like "gc@10", we make symlinks called "gc"
56 * and "@10" to it.
57 */
58
59/*
60 * Add a property to a node
61 */
62static struct proc_dir_entry *
63__proc_device_tree_add_prop(struct proc_dir_entry *de, struct property *pp,
64 const char *name)
65{
66 struct proc_dir_entry *ent;
67
68 /*
69 * Unfortunately proc_register puts each new entry
70 * at the beginning of the list. So we rearrange them.
71 */
72 ent = proc_create_data(name,
73 strncmp(name, "security-", 9) ? S_IRUGO : S_IRUSR,
74 de, &property_proc_fops, pp);
75 if (ent == NULL)
76 return NULL;
77
78 if (!strncmp(name, "security-", 9))
79 ent->size = 0; /* don't leak number of password chars */
80 else
81 ent->size = pp->length;
82
83 return ent;
84}
85
86
87void proc_device_tree_add_prop(struct proc_dir_entry *pde, struct property *prop)
88{
89 __proc_device_tree_add_prop(pde, prop, prop->name);
90}
91
92void proc_device_tree_remove_prop(struct proc_dir_entry *pde,
93 struct property *prop)
94{
95 remove_proc_entry(prop->name, pde);
96}
97
98void proc_device_tree_update_prop(struct proc_dir_entry *pde,
99 struct property *newprop,
100 struct property *oldprop)
101{
102 struct proc_dir_entry *ent;
103
104 for (ent = pde->subdir; ent != NULL; ent = ent->next)
105 if (ent->data == oldprop)
106 break;
107 if (ent == NULL) {
108 printk(KERN_WARNING "device-tree: property \"%s\" "
109 " does not exist\n", oldprop->name);
110 } else {
111 ent->data = newprop;
112 ent->size = newprop->length;
113 }
114}
115
116/*
117 * Various dodgy firmware might give us nodes and/or properties with
118 * conflicting names. That's generally ok, except for exporting via /proc,
119 * so munge names here to ensure they're unique.
120 */
121
122static int duplicate_name(struct proc_dir_entry *de, const char *name)
123{
124 struct proc_dir_entry *ent;
125 int found = 0;
126
127 spin_lock(&proc_subdir_lock);
128
129 for (ent = de->subdir; ent != NULL; ent = ent->next) {
130 if (strcmp(ent->name, name) == 0) {
131 found = 1;
132 break;
133 }
134 }
135
136 spin_unlock(&proc_subdir_lock);
137
138 return found;
139}
140
141static const char *fixup_name(struct device_node *np, struct proc_dir_entry *de,
142 const char *name)
143{
144 char *fixed_name;
145 int fixup_len = strlen(name) + 2 + 1; /* name + #x + \0 */
146 int i = 1, size;
147
148realloc:
149 fixed_name = kmalloc(fixup_len, GFP_KERNEL);
150 if (fixed_name == NULL) {
151 printk(KERN_ERR "device-tree: Out of memory trying to fixup "
152 "name \"%s\"\n", name);
153 return name;
154 }
155
156retry:
157 size = snprintf(fixed_name, fixup_len, "%s#%d", name, i);
158 size++; /* account for NULL */
159
160 if (size > fixup_len) {
161 /* We ran out of space, free and reallocate. */
162 kfree(fixed_name);
163 fixup_len = size;
164 goto realloc;
165 }
166
167 if (duplicate_name(de, fixed_name)) {
168 /* Multiple duplicates. Retry with a different offset. */
169 i++;
170 goto retry;
171 }
172
173 printk(KERN_WARNING "device-tree: Duplicate name in %s, "
174 "renamed to \"%s\"\n", np->full_name, fixed_name);
175
176 return fixed_name;
177}
178
179/*
180 * Process a node, adding entries for its children and its properties.
181 */
182void proc_device_tree_add_node(struct device_node *np,
183 struct proc_dir_entry *de)
184{
185 struct property *pp;
186 struct proc_dir_entry *ent;
187 struct device_node *child;
188 const char *p;
189
190 set_node_proc_entry(np, de);
191 for (child = NULL; (child = of_get_next_child(np, child));) {
192 /* Use everything after the last slash, or the full name */
193 p = strrchr(child->full_name, '/');
194 if (!p)
195 p = child->full_name;
196 else
197 ++p;
198
199 if (duplicate_name(de, p))
200 p = fixup_name(np, de, p);
201
202 ent = proc_mkdir(p, de);
203 if (ent == NULL)
204 break;
205 proc_device_tree_add_node(child, ent);
206 }
207 of_node_put(child);
208
209 for (pp = np->properties; pp != NULL; pp = pp->next) {
210 p = pp->name;
211
212 if (strchr(p, '/'))
213 continue;
214
215 if (duplicate_name(de, p))
216 p = fixup_name(np, de, p);
217
218 ent = __proc_device_tree_add_prop(de, pp, p);
219 if (ent == NULL)
220 break;
221 }
222}
223
224/*
225 * Called on initialization to set up the /proc/device-tree subtree
226 */
227void __init proc_device_tree_init(void)
228{
229 struct device_node *root;
230
231 proc_device_tree = proc_mkdir("device-tree", NULL);
232 if (proc_device_tree == NULL)
233 return;
234 root = of_find_node_by_path("/");
235 if (root == NULL) {
236 pr_debug("/proc/device-tree: can't find root\n");
237 return;
238 }
239 proc_device_tree_add_node(root, proc_device_tree);
240 of_node_put(root);
241}