Loading...
1/*
2 * Functions for dealing with DT resolution
3 *
4 * Copyright (C) 2012 Pantelis Antoniou <panto@antoniou-consulting.com>
5 * Copyright (C) 2012 Texas Instruments Inc.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * version 2 as published by the Free Software Foundation.
10 */
11
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/of.h>
15#include <linux/of_device.h>
16#include <linux/string.h>
17#include <linux/ctype.h>
18#include <linux/errno.h>
19#include <linux/string.h>
20#include <linux/slab.h>
21
22/* illegal phandle value (set when unresolved) */
23#define OF_PHANDLE_ILLEGAL 0xdeadbeef
24
25/**
26 * Find a node with the give full name by recursively following any of
27 * the child node links.
28 */
29static struct device_node *__of_find_node_by_full_name(struct device_node *node,
30 const char *full_name)
31{
32 struct device_node *child, *found;
33
34 if (node == NULL)
35 return NULL;
36
37 /* check */
38 if (of_node_cmp(node->full_name, full_name) == 0)
39 return of_node_get(node);
40
41 for_each_child_of_node(node, child) {
42 found = __of_find_node_by_full_name(child, full_name);
43 if (found != NULL) {
44 of_node_put(child);
45 return found;
46 }
47 }
48
49 return NULL;
50}
51
52/*
53 * Find live tree's maximum phandle value.
54 */
55static phandle of_get_tree_max_phandle(void)
56{
57 struct device_node *node;
58 phandle phandle;
59 unsigned long flags;
60
61 /* now search recursively */
62 raw_spin_lock_irqsave(&devtree_lock, flags);
63 phandle = 0;
64 for_each_of_allnodes(node) {
65 if (node->phandle != OF_PHANDLE_ILLEGAL &&
66 node->phandle > phandle)
67 phandle = node->phandle;
68 }
69 raw_spin_unlock_irqrestore(&devtree_lock, flags);
70
71 return phandle;
72}
73
74/*
75 * Adjust a subtree's phandle values by a given delta.
76 * Makes sure not to just adjust the device node's phandle value,
77 * but modify the phandle properties values as well.
78 */
79static void __of_adjust_tree_phandles(struct device_node *node,
80 int phandle_delta)
81{
82 struct device_node *child;
83 struct property *prop;
84 phandle phandle;
85
86 /* first adjust the node's phandle direct value */
87 if (node->phandle != 0 && node->phandle != OF_PHANDLE_ILLEGAL)
88 node->phandle += phandle_delta;
89
90 /* now adjust phandle & linux,phandle values */
91 for_each_property_of_node(node, prop) {
92
93 /* only look for these two */
94 if (of_prop_cmp(prop->name, "phandle") != 0 &&
95 of_prop_cmp(prop->name, "linux,phandle") != 0)
96 continue;
97
98 /* must be big enough */
99 if (prop->length < 4)
100 continue;
101
102 /* read phandle value */
103 phandle = be32_to_cpup(prop->value);
104 if (phandle == OF_PHANDLE_ILLEGAL) /* unresolved */
105 continue;
106
107 /* adjust */
108 *(uint32_t *)prop->value = cpu_to_be32(node->phandle);
109 }
110
111 /* now do the children recursively */
112 for_each_child_of_node(node, child)
113 __of_adjust_tree_phandles(child, phandle_delta);
114}
115
116static int __of_adjust_phandle_ref(struct device_node *node,
117 struct property *rprop, int value)
118{
119 phandle phandle;
120 struct device_node *refnode;
121 struct property *sprop;
122 char *propval, *propcur, *propend, *nodestr, *propstr, *s;
123 int offset, propcurlen;
124 int err = 0;
125
126 /* make a copy */
127 propval = kmalloc(rprop->length, GFP_KERNEL);
128 if (!propval) {
129 pr_err("%s: Could not copy value of '%s'\n",
130 __func__, rprop->name);
131 return -ENOMEM;
132 }
133 memcpy(propval, rprop->value, rprop->length);
134
135 propend = propval + rprop->length;
136 for (propcur = propval; propcur < propend; propcur += propcurlen + 1) {
137 propcurlen = strlen(propcur);
138
139 nodestr = propcur;
140 s = strchr(propcur, ':');
141 if (!s) {
142 pr_err("%s: Illegal symbol entry '%s' (1)\n",
143 __func__, propcur);
144 err = -EINVAL;
145 goto err_fail;
146 }
147 *s++ = '\0';
148
149 propstr = s;
150 s = strchr(s, ':');
151 if (!s) {
152 pr_err("%s: Illegal symbol entry '%s' (2)\n",
153 __func__, (char *)rprop->value);
154 err = -EINVAL;
155 goto err_fail;
156 }
157
158 *s++ = '\0';
159 err = kstrtoint(s, 10, &offset);
160 if (err != 0) {
161 pr_err("%s: Could get offset '%s'\n",
162 __func__, (char *)rprop->value);
163 goto err_fail;
164 }
165
166 /* look into the resolve node for the full path */
167 refnode = __of_find_node_by_full_name(node, nodestr);
168 if (!refnode) {
169 pr_warn("%s: Could not find refnode '%s'\n",
170 __func__, (char *)rprop->value);
171 continue;
172 }
173
174 /* now find the property */
175 for_each_property_of_node(refnode, sprop) {
176 if (of_prop_cmp(sprop->name, propstr) == 0)
177 break;
178 }
179 of_node_put(refnode);
180
181 if (!sprop) {
182 pr_err("%s: Could not find property '%s'\n",
183 __func__, (char *)rprop->value);
184 err = -ENOENT;
185 goto err_fail;
186 }
187
188 phandle = value;
189 *(__be32 *)(sprop->value + offset) = cpu_to_be32(phandle);
190 }
191
192err_fail:
193 kfree(propval);
194 return err;
195}
196
197/* compare nodes taking into account that 'name' strips out the @ part */
198static int __of_node_name_cmp(const struct device_node *dn1,
199 const struct device_node *dn2)
200{
201 const char *n1 = strrchr(dn1->full_name, '/') ? : "/";
202 const char *n2 = strrchr(dn2->full_name, '/') ? : "/";
203
204 return of_node_cmp(n1, n2);
205}
206
207/*
208 * Adjust the local phandle references by the given phandle delta.
209 * Assumes the existances of a __local_fixups__ node at the root.
210 * Assumes that __of_verify_tree_phandle_references has been called.
211 * Does not take any devtree locks so make sure you call this on a tree
212 * which is at the detached state.
213 */
214static int __of_adjust_tree_phandle_references(struct device_node *node,
215 struct device_node *target, int phandle_delta)
216{
217 struct device_node *child, *childtarget;
218 struct property *rprop, *sprop;
219 int err, i, count;
220 unsigned int off;
221 phandle phandle;
222
223 if (node == NULL)
224 return 0;
225
226 for_each_property_of_node(node, rprop) {
227
228 /* skip properties added automatically */
229 if (of_prop_cmp(rprop->name, "name") == 0 ||
230 of_prop_cmp(rprop->name, "phandle") == 0 ||
231 of_prop_cmp(rprop->name, "linux,phandle") == 0)
232 continue;
233
234 if ((rprop->length % 4) != 0 || rprop->length == 0) {
235 pr_err("%s: Illegal property (size) '%s' @%s\n",
236 __func__, rprop->name, node->full_name);
237 return -EINVAL;
238 }
239 count = rprop->length / sizeof(__be32);
240
241 /* now find the target property */
242 for_each_property_of_node(target, sprop) {
243 if (of_prop_cmp(sprop->name, rprop->name) == 0)
244 break;
245 }
246
247 if (sprop == NULL) {
248 pr_err("%s: Could not find target property '%s' @%s\n",
249 __func__, rprop->name, node->full_name);
250 return -EINVAL;
251 }
252
253 for (i = 0; i < count; i++) {
254 off = be32_to_cpu(((__be32 *)rprop->value)[i]);
255 /* make sure the offset doesn't overstep (even wrap) */
256 if (off >= sprop->length ||
257 (off + 4) > sprop->length) {
258 pr_err("%s: Illegal property '%s' @%s\n",
259 __func__, rprop->name,
260 node->full_name);
261 return -EINVAL;
262 }
263
264 if (phandle_delta) {
265 /* adjust */
266 phandle = be32_to_cpu(*(__be32 *)(sprop->value + off));
267 phandle += phandle_delta;
268 *(__be32 *)(sprop->value + off) = cpu_to_be32(phandle);
269 }
270 }
271 }
272
273 for_each_child_of_node(node, child) {
274
275 for_each_child_of_node(target, childtarget)
276 if (__of_node_name_cmp(child, childtarget) == 0)
277 break;
278
279 if (!childtarget) {
280 pr_err("%s: Could not find target child '%s' @%s\n",
281 __func__, child->name, node->full_name);
282 return -EINVAL;
283 }
284
285 err = __of_adjust_tree_phandle_references(child, childtarget,
286 phandle_delta);
287 if (err != 0)
288 return err;
289 }
290
291 return 0;
292}
293
294/**
295 * of_resolve - Resolve the given node against the live tree.
296 *
297 * @resolve: Node to resolve
298 *
299 * Perform dynamic Device Tree resolution against the live tree
300 * to the given node to resolve. This depends on the live tree
301 * having a __symbols__ node, and the resolve node the __fixups__ &
302 * __local_fixups__ nodes (if needed).
303 * The result of the operation is a resolve node that it's contents
304 * are fit to be inserted or operate upon the live tree.
305 * Returns 0 on success or a negative error value on error.
306 */
307int of_resolve_phandles(struct device_node *resolve)
308{
309 struct device_node *child, *childroot, *refnode;
310 struct device_node *root_sym, *resolve_sym, *resolve_fix;
311 struct property *rprop;
312 const char *refpath;
313 phandle phandle, phandle_delta;
314 int err;
315
316 /* the resolve node must exist, and be detached */
317 if (!resolve || !of_node_check_flag(resolve, OF_DETACHED))
318 return -EINVAL;
319
320 /* first we need to adjust the phandles */
321 phandle_delta = of_get_tree_max_phandle() + 1;
322 __of_adjust_tree_phandles(resolve, phandle_delta);
323
324 /* locate the local fixups */
325 childroot = NULL;
326 for_each_child_of_node(resolve, childroot)
327 if (of_node_cmp(childroot->name, "__local_fixups__") == 0)
328 break;
329
330 if (childroot != NULL) {
331 /* resolve root is guaranteed to be the '/' */
332 err = __of_adjust_tree_phandle_references(childroot,
333 resolve, 0);
334 if (err != 0)
335 return err;
336
337 BUG_ON(__of_adjust_tree_phandle_references(childroot,
338 resolve, phandle_delta));
339 }
340
341 root_sym = NULL;
342 resolve_sym = NULL;
343 resolve_fix = NULL;
344
345 /* this may fail (if no fixups are required) */
346 root_sym = of_find_node_by_path("/__symbols__");
347
348 /* locate the symbols & fixups nodes on resolve */
349 for_each_child_of_node(resolve, child) {
350
351 if (!resolve_sym &&
352 of_node_cmp(child->name, "__symbols__") == 0)
353 resolve_sym = child;
354
355 if (!resolve_fix &&
356 of_node_cmp(child->name, "__fixups__") == 0)
357 resolve_fix = child;
358
359 /* both found, don't bother anymore */
360 if (resolve_sym && resolve_fix)
361 break;
362 }
363
364 /* we do allow for the case where no fixups are needed */
365 if (!resolve_fix) {
366 err = 0; /* no error */
367 goto out;
368 }
369
370 /* we need to fixup, but no root symbols... */
371 if (!root_sym) {
372 err = -EINVAL;
373 goto out;
374 }
375
376 for_each_property_of_node(resolve_fix, rprop) {
377
378 /* skip properties added automatically */
379 if (of_prop_cmp(rprop->name, "name") == 0)
380 continue;
381
382 err = of_property_read_string(root_sym,
383 rprop->name, &refpath);
384 if (err != 0) {
385 pr_err("%s: Could not find symbol '%s'\n",
386 __func__, rprop->name);
387 goto out;
388 }
389
390 refnode = of_find_node_by_path(refpath);
391 if (!refnode) {
392 pr_err("%s: Could not find node by path '%s'\n",
393 __func__, refpath);
394 err = -ENOENT;
395 goto out;
396 }
397
398 phandle = refnode->phandle;
399 of_node_put(refnode);
400
401 pr_debug("%s: %s phandle is 0x%08x\n",
402 __func__, rprop->name, phandle);
403
404 err = __of_adjust_phandle_ref(resolve, rprop, phandle);
405 if (err)
406 break;
407 }
408
409out:
410 /* NULL is handled by of_node_put as NOP */
411 of_node_put(root_sym);
412
413 return err;
414}
415EXPORT_SYMBOL_GPL(of_resolve_phandles);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Functions for dealing with DT resolution
4 *
5 * Copyright (C) 2012 Pantelis Antoniou <panto@antoniou-consulting.com>
6 * Copyright (C) 2012 Texas Instruments Inc.
7 */
8
9#define pr_fmt(fmt) "OF: resolver: " fmt
10
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/of.h>
14#include <linux/of_device.h>
15#include <linux/string.h>
16#include <linux/ctype.h>
17#include <linux/errno.h>
18#include <linux/slab.h>
19
20#include "of_private.h"
21
22static phandle live_tree_max_phandle(void)
23{
24 struct device_node *node;
25 phandle phandle;
26 unsigned long flags;
27
28 raw_spin_lock_irqsave(&devtree_lock, flags);
29 phandle = 0;
30 for_each_of_allnodes(node) {
31 if (node->phandle != OF_PHANDLE_ILLEGAL &&
32 node->phandle > phandle)
33 phandle = node->phandle;
34 }
35 raw_spin_unlock_irqrestore(&devtree_lock, flags);
36
37 return phandle;
38}
39
40static void adjust_overlay_phandles(struct device_node *overlay,
41 int phandle_delta)
42{
43 struct device_node *child;
44 struct property *prop;
45 phandle phandle;
46
47 /* adjust node's phandle in node */
48 if (overlay->phandle != 0 && overlay->phandle != OF_PHANDLE_ILLEGAL)
49 overlay->phandle += phandle_delta;
50
51 /* copy adjusted phandle into *phandle properties */
52 for_each_property_of_node(overlay, prop) {
53
54 if (of_prop_cmp(prop->name, "phandle") &&
55 of_prop_cmp(prop->name, "linux,phandle"))
56 continue;
57
58 if (prop->length < 4)
59 continue;
60
61 phandle = be32_to_cpup(prop->value);
62 if (phandle == OF_PHANDLE_ILLEGAL)
63 continue;
64
65 *(__be32 *)prop->value = cpu_to_be32(overlay->phandle);
66 }
67
68 for_each_child_of_node(overlay, child)
69 adjust_overlay_phandles(child, phandle_delta);
70}
71
72static int update_usages_of_a_phandle_reference(struct device_node *overlay,
73 struct property *prop_fixup, phandle phandle)
74{
75 struct device_node *refnode;
76 struct property *prop;
77 char *value, *cur, *end, *node_path, *prop_name, *s;
78 int offset, len;
79 int err = 0;
80
81 value = kmemdup(prop_fixup->value, prop_fixup->length, GFP_KERNEL);
82 if (!value)
83 return -ENOMEM;
84
85 /* prop_fixup contains a list of tuples of path:property_name:offset */
86 end = value + prop_fixup->length;
87 for (cur = value; cur < end; cur += len + 1) {
88 len = strlen(cur);
89
90 node_path = cur;
91 s = strchr(cur, ':');
92 if (!s) {
93 err = -EINVAL;
94 goto err_fail;
95 }
96 *s++ = '\0';
97
98 prop_name = s;
99 s = strchr(s, ':');
100 if (!s) {
101 err = -EINVAL;
102 goto err_fail;
103 }
104 *s++ = '\0';
105
106 err = kstrtoint(s, 10, &offset);
107 if (err)
108 goto err_fail;
109
110 refnode = __of_find_node_by_full_path(of_node_get(overlay), node_path);
111 if (!refnode)
112 continue;
113
114 for_each_property_of_node(refnode, prop) {
115 if (!of_prop_cmp(prop->name, prop_name))
116 break;
117 }
118 of_node_put(refnode);
119
120 if (!prop) {
121 err = -ENOENT;
122 goto err_fail;
123 }
124
125 *(__be32 *)(prop->value + offset) = cpu_to_be32(phandle);
126 }
127
128err_fail:
129 kfree(value);
130 return err;
131}
132
133/* compare nodes taking into account that 'name' strips out the @ part */
134static int node_name_cmp(const struct device_node *dn1,
135 const struct device_node *dn2)
136{
137 const char *n1 = kbasename(dn1->full_name);
138 const char *n2 = kbasename(dn2->full_name);
139
140 return of_node_cmp(n1, n2);
141}
142
143/*
144 * Adjust the local phandle references by the given phandle delta.
145 *
146 * Subtree @local_fixups, which is overlay node __local_fixups__,
147 * mirrors the fragment node structure at the root of the overlay.
148 *
149 * For each property in the fragments that contains a phandle reference,
150 * @local_fixups has a property of the same name that contains a list
151 * of offsets of the phandle reference(s) within the respective property
152 * value(s). The values at these offsets will be fixed up.
153 */
154static int adjust_local_phandle_references(struct device_node *local_fixups,
155 struct device_node *overlay, int phandle_delta)
156{
157 struct device_node *child, *overlay_child;
158 struct property *prop_fix, *prop;
159 int err, i, count;
160 unsigned int off;
161
162 if (!local_fixups)
163 return 0;
164
165 for_each_property_of_node(local_fixups, prop_fix) {
166
167 /* skip properties added automatically */
168 if (!of_prop_cmp(prop_fix->name, "name") ||
169 !of_prop_cmp(prop_fix->name, "phandle") ||
170 !of_prop_cmp(prop_fix->name, "linux,phandle"))
171 continue;
172
173 if ((prop_fix->length % 4) != 0 || prop_fix->length == 0)
174 return -EINVAL;
175 count = prop_fix->length / sizeof(__be32);
176
177 for_each_property_of_node(overlay, prop) {
178 if (!of_prop_cmp(prop->name, prop_fix->name))
179 break;
180 }
181
182 if (!prop)
183 return -EINVAL;
184
185 for (i = 0; i < count; i++) {
186 off = be32_to_cpu(((__be32 *)prop_fix->value)[i]);
187 if ((off + 4) > prop->length)
188 return -EINVAL;
189
190 be32_add_cpu(prop->value + off, phandle_delta);
191 }
192 }
193
194 /*
195 * These nested loops recurse down two subtrees in parallel, where the
196 * node names in the two subtrees match.
197 *
198 * The roots of the subtrees are the overlay's __local_fixups__ node
199 * and the overlay's root node.
200 */
201 for_each_child_of_node(local_fixups, child) {
202
203 for_each_child_of_node(overlay, overlay_child)
204 if (!node_name_cmp(child, overlay_child))
205 break;
206
207 if (!overlay_child)
208 return -EINVAL;
209
210 err = adjust_local_phandle_references(child, overlay_child,
211 phandle_delta);
212 if (err)
213 return err;
214 }
215
216 return 0;
217}
218
219/**
220 * of_resolve_phandles - Relocate and resolve overlay against live tree
221 *
222 * @overlay: Pointer to devicetree overlay to relocate and resolve
223 *
224 * Modify (relocate) values of local phandles in @overlay to a range that
225 * does not conflict with the live expanded devicetree. Update references
226 * to the local phandles in @overlay. Update (resolve) phandle references
227 * in @overlay that refer to the live expanded devicetree.
228 *
229 * Phandle values in the live tree are in the range of
230 * 1 .. live_tree_max_phandle(). The range of phandle values in the overlay
231 * also begin with at 1. Adjust the phandle values in the overlay to begin
232 * at live_tree_max_phandle() + 1. Update references to the phandles to
233 * the adjusted phandle values.
234 *
235 * The name of each property in the "__fixups__" node in the overlay matches
236 * the name of a symbol (a label) in the live tree. The values of each
237 * property in the "__fixups__" node is a list of the property values in the
238 * overlay that need to be updated to contain the phandle reference
239 * corresponding to that symbol in the live tree. Update the references in
240 * the overlay with the phandle values in the live tree.
241 *
242 * @overlay must be detached.
243 *
244 * Resolving and applying @overlay to the live expanded devicetree must be
245 * protected by a mechanism to ensure that multiple overlays are processed
246 * in a single threaded manner so that multiple overlays will not relocate
247 * phandles to overlapping ranges. The mechanism to enforce this is not
248 * yet implemented.
249 *
250 * Return: %0 on success or a negative error value on error.
251 */
252int of_resolve_phandles(struct device_node *overlay)
253{
254 struct device_node *child, *local_fixups, *refnode;
255 struct device_node *tree_symbols, *overlay_fixups;
256 struct property *prop;
257 const char *refpath;
258 phandle phandle, phandle_delta;
259 int err;
260
261 tree_symbols = NULL;
262
263 if (!overlay) {
264 pr_err("null overlay\n");
265 err = -EINVAL;
266 goto out;
267 }
268
269 if (!of_node_check_flag(overlay, OF_DETACHED)) {
270 pr_err("overlay not detached\n");
271 err = -EINVAL;
272 goto out;
273 }
274
275 phandle_delta = live_tree_max_phandle() + 1;
276 adjust_overlay_phandles(overlay, phandle_delta);
277
278 for_each_child_of_node(overlay, local_fixups)
279 if (!of_node_cmp(local_fixups->name, "__local_fixups__"))
280 break;
281
282 err = adjust_local_phandle_references(local_fixups, overlay, phandle_delta);
283 if (err)
284 goto out;
285
286 overlay_fixups = NULL;
287
288 for_each_child_of_node(overlay, child) {
289 if (!of_node_cmp(child->name, "__fixups__"))
290 overlay_fixups = child;
291 }
292
293 if (!overlay_fixups) {
294 err = 0;
295 goto out;
296 }
297
298 tree_symbols = of_find_node_by_path("/__symbols__");
299 if (!tree_symbols) {
300 pr_err("no symbols in root of device tree.\n");
301 err = -EINVAL;
302 goto out;
303 }
304
305 for_each_property_of_node(overlay_fixups, prop) {
306
307 /* skip properties added automatically */
308 if (!of_prop_cmp(prop->name, "name"))
309 continue;
310
311 err = of_property_read_string(tree_symbols,
312 prop->name, &refpath);
313 if (err)
314 goto out;
315
316 refnode = of_find_node_by_path(refpath);
317 if (!refnode) {
318 err = -ENOENT;
319 goto out;
320 }
321
322 phandle = refnode->phandle;
323 of_node_put(refnode);
324
325 err = update_usages_of_a_phandle_reference(overlay, prop, phandle);
326 if (err)
327 break;
328 }
329
330out:
331 if (err)
332 pr_err("overlay phandle fixup failed: %d\n", err);
333 of_node_put(tree_symbols);
334
335 return err;
336}
337EXPORT_SYMBOL_GPL(of_resolve_phandles);