1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * tree.c: Basic device tree traversal/scanning for the Linux
4 * prom library.
5 *
6 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
7 */
8
9 #include <linux/string.h>
10 #include <linux/types.h>
11 #include <linux/kernel.h>
12 #include <linux/sched.h>
13 #include <linux/ctype.h>
14 #include <linux/module.h>
15
16 #include <asm/openprom.h>
17 #include <asm/oplib.h>
18
19 extern void restore_current(void);
20
21 static char promlib_buf[128];
22
23 /* Internal version of prom_getchild that does not alter return values. */
24 static phandle __prom_getchild(phandle node)
25 {
26 unsigned long flags;
27 phandle cnode;
28
29 spin_lock_irqsave(&prom_lock, flags);
30 cnode = prom_nodeops->no_child(node);
31 restore_current();
32 spin_unlock_irqrestore(&prom_lock, flags);
33
34 return cnode;
35 }
36
37 /* Return the child of node 'node' or zero if no this node has no
38 * direct descendent.
39 */
40 phandle prom_getchild(phandle node)
41 {
42 phandle cnode;
43
44 if ((s32)node == -1)
45 return 0;
46
47 cnode = __prom_getchild(node);
48 if (cnode == 0 || (s32)cnode == -1)
49 return 0;
50
51 return cnode;
52 }
53 EXPORT_SYMBOL(prom_getchild);
54
55 /* Internal version of prom_getsibling that does not alter return values. */
56 static phandle __prom_getsibling(phandle node)
57 {
58 unsigned long flags;
59 phandle cnode;
60
61 spin_lock_irqsave(&prom_lock, flags);
62 cnode = prom_nodeops->no_nextnode(node);
63 restore_current();
64 spin_unlock_irqrestore(&prom_lock, flags);
65
66 return cnode;
67 }
68
69 /* Return the next sibling of node 'node' or zero if no more siblings
70 * at this level of depth in the tree.
71 */
72 phandle prom_getsibling(phandle node)
73 {
74 phandle sibnode;
75
76 if ((s32)node == -1)
77 return 0;
78
79 sibnode = __prom_getsibling(node);
80 if (sibnode == 0 || (s32)sibnode == -1)
81 return 0;
82
83 return sibnode;
84 }
85 EXPORT_SYMBOL(prom_getsibling);
86
87 /* Return the length in bytes of property 'prop' at node 'node'.
88 * Return -1 on error.
89 */
90 int prom_getproplen(phandle node, const char *prop)
91 {
92 int ret;
93 unsigned long flags;
94
95 if((!node) || (!prop))
96 return -1;
97
98 spin_lock_irqsave(&prom_lock, flags);
99 ret = prom_nodeops->no_proplen(node, prop);
100 restore_current();
101 spin_unlock_irqrestore(&prom_lock, flags);
102 return ret;
103 }
104 EXPORT_SYMBOL(prom_getproplen);
105
106 /* Acquire a property 'prop' at node 'node' and place it in
107 * 'buffer' which has a size of 'bufsize'. If the acquisition
108 * was successful the length will be returned, else -1 is returned.
109 */
110 int prom_getproperty(phandle node, const char *prop, char *buffer, int bufsize)
111 {
112 int plen, ret;
113 unsigned long flags;
114
115 plen = prom_getproplen(node, prop);
116 if((plen > bufsize) || (plen == 0) || (plen == -1))
117 return -1;
118 /* Ok, things seem all right. */
119 spin_lock_irqsave(&prom_lock, flags);
120 ret = prom_nodeops->no_getprop(node, prop, buffer);
121 restore_current();
122 spin_unlock_irqrestore(&prom_lock, flags);
123 return ret;
124 }
125 EXPORT_SYMBOL(prom_getproperty);
126
127 /* Acquire an integer property and return its value. Returns -1
128 * on failure.
129 */
130 int prom_getint(phandle node, char *prop)
131 {
132 static int intprop;
133
134 if(prom_getproperty(node, prop, (char *) &intprop, sizeof(int)) != -1)
135 return intprop;
136
137 return -1;
138 }
139 EXPORT_SYMBOL(prom_getint);
140
141 /* Acquire an integer property, upon error return the passed default
142 * integer.
143 */
144 int prom_getintdefault(phandle node, char *property, int deflt)
145 {
146 int retval;
147
148 retval = prom_getint(node, property);
149 if(retval == -1) return deflt;
150
151 return retval;
152 }
153 EXPORT_SYMBOL(prom_getintdefault);
154
155 /* Acquire a boolean property, 1=TRUE 0=FALSE. */
156 int prom_getbool(phandle node, char *prop)
157 {
158 int retval;
159
160 retval = prom_getproplen(node, prop);
161 if(retval == -1) return 0;
162 return 1;
163 }
164 EXPORT_SYMBOL(prom_getbool);
165
166 /* Acquire a property whose value is a string, returns a null
167 * string on error. The char pointer is the user supplied string
168 * buffer.
169 */
170 void prom_getstring(phandle node, char *prop, char *user_buf, int ubuf_size)
171 {
172 int len;
173
174 len = prom_getproperty(node, prop, user_buf, ubuf_size);
175 if(len != -1) return;
176 user_buf[0] = 0;
177 }
178 EXPORT_SYMBOL(prom_getstring);
179
180
181 /* Search siblings at 'node_start' for a node with name
182 * 'nodename'. Return node if successful, zero if not.
183 */
184 phandle prom_searchsiblings(phandle node_start, char *nodename)
185 {
186
187 phandle thisnode;
188 int error;
189
190 for(thisnode = node_start; thisnode;
191 thisnode=prom_getsibling(thisnode)) {
192 error = prom_getproperty(thisnode, "name", promlib_buf,
193 sizeof(promlib_buf));
194 /* Should this ever happen? */
195 if(error == -1) continue;
196 if(strcmp(nodename, promlib_buf)==0) return thisnode;
197 }
198
199 return 0;
200 }
201 EXPORT_SYMBOL(prom_searchsiblings);
202
203 /* Interal version of nextprop that does not alter return values. */
204 static char *__prom_nextprop(phandle node, char * oprop)
205 {
206 unsigned long flags;
207 char *prop;
208
209 spin_lock_irqsave(&prom_lock, flags);
210 prop = prom_nodeops->no_nextprop(node, oprop);
211 restore_current();
212 spin_unlock_irqrestore(&prom_lock, flags);
213
214 return prop;
215 }
216
217 /* Return the property type string after property type 'oprop'
218 * at node 'node' . Returns empty string if no more
219 * property types for this node.
220 */
221 char *prom_nextprop(phandle node, char *oprop, char *buffer)
222 {
223 if (node == 0 || (s32)node == -1)
224 return "";
225
226 return __prom_nextprop(node, oprop);
227 }
228 EXPORT_SYMBOL(prom_nextprop);
229
230 phandle prom_finddevice(char *name)
231 {
232 char nbuf[128];
233 char *s = name, *d;
234 phandle node = prom_root_node, node2;
235 unsigned int which_io, phys_addr;
236 struct linux_prom_registers reg[PROMREG_MAX];
237
238 while (*s++) {
239 if (!*s) return node; /* path '.../' is legal */
240 node = prom_getchild(node);
241
242 for (d = nbuf; *s != 0 && *s != '@' && *s != '/';)
243 *d++ = *s++;
244 *d = 0;
245
246 node = prom_searchsiblings(node, nbuf);
247 if (!node)
248 return 0;
249
250 if (*s == '@') {
251 if (isxdigit(s[1]) && s[2] == ',') {
252 which_io = simple_strtoul(s+1, NULL, 16);
253 phys_addr = simple_strtoul(s+3, &d, 16);
254 if (d != s + 3 && (!*d || *d == '/')
255 && d <= s + 3 + 8) {
256 node2 = node;
257 while (node2 && (s32)node2 != -1) {
258 if (prom_getproperty (node2, "reg", (char *)reg, sizeof (reg)) > 0) {
259 if (which_io == reg[0].which_io && phys_addr == reg[0].phys_addr) {
260 node = node2;
261 break;
262 }
263 }
264 node2 = prom_getsibling(node2);
265 if (!node2 || (s32)node2 == -1)
266 break;
267 node2 = prom_searchsiblings(prom_getsibling(node2), nbuf);
268 }
269 }
270 }
271 while (*s != 0 && *s != '/') s++;
272 }
273 }
274 return node;
275 }
276 EXPORT_SYMBOL(prom_finddevice);
277
278 /* Set property 'pname' at node 'node' to value 'value' which has a length
279 * of 'size' bytes. Return the number of bytes the prom accepted.
280 */
281 int prom_setprop(phandle node, const char *pname, char *value, int size)
282 {
283 unsigned long flags;
284 int ret;
285
286 if (size == 0)
287 return 0;
288 if ((pname == NULL) || (value == NULL))
289 return 0;
290 spin_lock_irqsave(&prom_lock, flags);
291 ret = prom_nodeops->no_setprop(node, pname, value, size);
292 restore_current();
293 spin_unlock_irqrestore(&prom_lock, flags);
294 return ret;
295 }
296 EXPORT_SYMBOL(prom_setprop);
297
298 phandle prom_inst2pkg(int inst)
299 {
300 phandle node;
301 unsigned long flags;
302
303 spin_lock_irqsave(&prom_lock, flags);
304 node = (*romvec->pv_v2devops.v2_inst2pkg)(inst);
305 restore_current();
306 spin_unlock_irqrestore(&prom_lock, flags);
307 if ((s32)node == -1)
308 return 0;
309 return node;
310 }
311
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