1 /*
2 * proc_devtree.c - handles /proc/device-tree
3 *
4 * Copyright 1997 Paul Mackerras
5 */
6 #include <linux/errno.h>
7 #include <linux/sched.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 static struct proc_dir_entry *proc_device_tree;
15
16 /*
17 * Supply data on a read from /proc/device-tree/node/property.
18 */
19 static int property_read_proc(char *page, char **start, off_t off,
20 int count, int *eof, void *data)
21 {
22 struct property *pp = data;
23 int n;
24
25 if (off >= pp->length) {
26 *eof = 1;
27 return 0;
28 }
29 n = pp->length - off;
30 if (n > count)
31 n = count;
32 else
33 *eof = 1;
34 memcpy(page, pp->value + off, n);
35 *start = page;
36 return n;
37 }
38
39 /*
40 * For a node with a name like "gc@10", we make symlinks called "gc"
41 * and "@10" to it.
42 */
43
44 /*
45 * Process a node, adding entries for its children and its properties.
46 */
47 static void add_node(struct device_node *np, struct proc_dir_entry *de)
48 {
49 struct property *pp;
50 struct proc_dir_entry *ent;
51 struct device_node *child, *sib;
52 const char *p, *at;
53 int l;
54 struct proc_dir_entry *list, **lastp, *al;
55
56 lastp = &list;
57 for (pp = np->properties; pp != 0; pp = pp->next) {
58 /*
59 * Unfortunately proc_register puts each new entry
60 * at the beginning of the list. So we rearrange them.
61 */
62 ent = create_proc_read_entry(pp->name, S_IRUGO, de,
63 property_read_proc, pp);
64 if (ent == 0)
65 break;
66 ent->size = pp->length;
67 *lastp = ent;
68 lastp = &ent->next;
69 }
70 for (child = np->child; child != 0; child = child->sibling) {
71 p = strrchr(child->full_name, '/');
72 if (p == 0)
73 p = child->full_name;
74 else
75 ++p;
76 /* chop off '@0' if the name ends with that */
77 l = strlen(p);
78 if (l > 2 && p[l-2] == '@' && p[l-1] == '')
79 l -= 2;
80 ent = proc_mkdir(p, de);
81 if (ent == 0)
82 break;
83 *lastp = ent;
84 lastp = &ent->next;
85 add_node(child, ent);
86
87 /*
88 * If we left the address part on the name, consider
89 * adding symlinks from the name and address parts.
90 */
91 if (p[l] != 0 || (at = strchr(p, '@')) == 0)
92 continue;
93
94 /*
95 * If this is the first node with a given name property,
96 * add a symlink with the name property as its name.
97 */
98 for (sib = np->child; sib != child; sib = sib->sibling)
99 if (sib->name && strcmp(sib->name, child->name) == 0)
100 break;
101 if (sib == child && strncmp(p, child->name, l) != 0) {
102 al = proc_symlink(child->name, de, ent->name);
103 if (al == 0)
104 break;
105 *lastp = al;
106 lastp = &al->next;
107 }
108
109 /*
110 * Add another directory with the @address part as its name.
111 */
112 al = proc_symlink(at, de, ent->name);
113 if (al == 0)
114 break;
115 *lastp = al;
116 lastp = &al->next;
117 }
118 *lastp = 0;
119 de->subdir = list;
120 }
121
122 /*
123 * Called on initialization to set up the /proc/device-tree subtree
124 */
125 void proc_device_tree_init(void)
126 {
127 struct device_node *root;
128 if ( !have_of )
129 return;
130 proc_device_tree = proc_mkdir("device-tree", 0);
131 if (proc_device_tree == 0)
132 return;
133 root = find_path_device("/");
134 if (root == 0) {
135 printk(KERN_ERR "/proc/device-tree: can't find root\n");
136 return;
137 }
138 add_node(root, proc_device_tree);
139 }
140
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