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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 | |
20 | static 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 | |
28 | static struct proc_dir_entry *proc_device_tree; |
29 | |
30 | /* |
31 | * Supply data on a read from /proc/device-tree/node/property. |
32 | */ |
33 | static 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 | |
41 | static int property_proc_open(struct inode *inode, struct file *file) |
42 | { |
43 | return single_open(file, property_proc_show, PDE(inode)->data); |
44 | } |
45 | |
46 | static 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 | */ |
62 | static 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 | |
87 | void 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 | |
92 | void proc_device_tree_remove_prop(struct proc_dir_entry *pde, |
93 | struct property *prop) |
94 | { |
95 | remove_proc_entry(prop->name, pde); |
96 | } |
97 | |
98 | void 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 | |
122 | static 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 | |
141 | static 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 | |
148 | realloc: |
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 | |
156 | retry: |
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 | */ |
182 | void 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 | */ |
227 | void __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 | } |
242 |
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