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
19extern void restore_current(void);
20
21static char promlib_buf[128];
22
23/* Internal version of prom_getchild that does not alter return values. */
24static 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 */
40phandle 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}
53EXPORT_SYMBOL(prom_getchild);
54
55/* Internal version of prom_getsibling that does not alter return values. */
56static 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 */
72phandle 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}
85EXPORT_SYMBOL(prom_getsibling);
86
87/* Return the length in bytes of property 'prop' at node 'node'.
88 * Return -1 on error.
89 */
90int 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}
104EXPORT_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 */
110int 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}
125EXPORT_SYMBOL(prom_getproperty);
126
127/* Acquire an integer property and return its value.  Returns -1
128 * on failure.
129 */
130int 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}
139EXPORT_SYMBOL(prom_getint);
140
141/* Acquire an integer property, upon error return the passed default
142 * integer.
143 */
144int 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}
153EXPORT_SYMBOL(prom_getintdefault);
154
155/* Acquire a boolean property, 1=TRUE 0=FALSE. */
156int 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}
164EXPORT_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 */
170void 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}
178EXPORT_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 */
184phandle 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}
201EXPORT_SYMBOL(prom_searchsiblings);
202
203/* Interal version of nextprop that does not alter return values. */
204static 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 */
221char *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}
228EXPORT_SYMBOL(prom_nextprop);
229
230phandle 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}
276EXPORT_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 */
281int 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}
296EXPORT_SYMBOL(prom_setprop);
297
298phandle 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