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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#define pr_fmt(fmt) "OF: resolver: " fmt
13
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/of.h>
17#include <linux/of_device.h>
18#include <linux/string.h>
19#include <linux/ctype.h>
20#include <linux/errno.h>
21#include <linux/string.h>
22#include <linux/slab.h>
23
24/* illegal phandle value (set when unresolved) */
25#define OF_PHANDLE_ILLEGAL 0xdeadbeef
26
27/**
28 * Find a node with the give full name by recursively following any of
29 * the child node links.
30 */
31static struct device_node *find_node_by_full_name(struct device_node *node,
32 const char *full_name)
33{
34 struct device_node *child, *found;
35
36 if (!node)
37 return NULL;
38
39 if (!of_node_cmp(node->full_name, full_name))
40 return of_node_get(node);
41
42 for_each_child_of_node(node, child) {
43 found = find_node_by_full_name(child, full_name);
44 if (found != NULL) {
45 of_node_put(child);
46 return found;
47 }
48 }
49
50 return NULL;
51}
52
53static phandle live_tree_max_phandle(void)
54{
55 struct device_node *node;
56 phandle phandle;
57 unsigned long flags;
58
59 raw_spin_lock_irqsave(&devtree_lock, flags);
60 phandle = 0;
61 for_each_of_allnodes(node) {
62 if (node->phandle != OF_PHANDLE_ILLEGAL &&
63 node->phandle > phandle)
64 phandle = node->phandle;
65 }
66 raw_spin_unlock_irqrestore(&devtree_lock, flags);
67
68 return phandle;
69}
70
71static void adjust_overlay_phandles(struct device_node *overlay,
72 int phandle_delta)
73{
74 struct device_node *child;
75 struct property *prop;
76 phandle phandle;
77
78 /* adjust node's phandle in node */
79 if (overlay->phandle != 0 && overlay->phandle != OF_PHANDLE_ILLEGAL)
80 overlay->phandle += phandle_delta;
81
82 /* copy adjusted phandle into *phandle properties */
83 for_each_property_of_node(overlay, prop) {
84
85 if (of_prop_cmp(prop->name, "phandle") &&
86 of_prop_cmp(prop->name, "linux,phandle"))
87 continue;
88
89 if (prop->length < 4)
90 continue;
91
92 phandle = be32_to_cpup(prop->value);
93 if (phandle == OF_PHANDLE_ILLEGAL)
94 continue;
95
96 *(uint32_t *)prop->value = cpu_to_be32(overlay->phandle);
97 }
98
99 for_each_child_of_node(overlay, child)
100 adjust_overlay_phandles(child, phandle_delta);
101}
102
103static int update_usages_of_a_phandle_reference(struct device_node *overlay,
104 struct property *prop_fixup, phandle phandle)
105{
106 struct device_node *refnode;
107 struct property *prop;
108 char *value, *cur, *end, *node_path, *prop_name, *s;
109 int offset, len;
110 int err = 0;
111
112 value = kmalloc(prop_fixup->length, GFP_KERNEL);
113 if (!value)
114 return -ENOMEM;
115 memcpy(value, prop_fixup->value, prop_fixup->length);
116
117 /* prop_fixup contains a list of tuples of path:property_name:offset */
118 end = value + prop_fixup->length;
119 for (cur = value; cur < end; cur += len + 1) {
120 len = strlen(cur);
121
122 node_path = cur;
123 s = strchr(cur, ':');
124 if (!s) {
125 err = -EINVAL;
126 goto err_fail;
127 }
128 *s++ = '\0';
129
130 prop_name = s;
131 s = strchr(s, ':');
132 if (!s) {
133 err = -EINVAL;
134 goto err_fail;
135 }
136 *s++ = '\0';
137
138 err = kstrtoint(s, 10, &offset);
139 if (err)
140 goto err_fail;
141
142 refnode = find_node_by_full_name(overlay, node_path);
143 if (!refnode)
144 continue;
145
146 for_each_property_of_node(refnode, prop) {
147 if (!of_prop_cmp(prop->name, prop_name))
148 break;
149 }
150 of_node_put(refnode);
151
152 if (!prop) {
153 err = -ENOENT;
154 goto err_fail;
155 }
156
157 *(__be32 *)(prop->value + offset) = cpu_to_be32(phandle);
158 }
159
160err_fail:
161 kfree(value);
162 return err;
163}
164
165/* compare nodes taking into account that 'name' strips out the @ part */
166static int node_name_cmp(const struct device_node *dn1,
167 const struct device_node *dn2)
168{
169 const char *n1 = strrchr(dn1->full_name, '/') ? : "/";
170 const char *n2 = strrchr(dn2->full_name, '/') ? : "/";
171
172 return of_node_cmp(n1, n2);
173}
174
175/*
176 * Adjust the local phandle references by the given phandle delta.
177 *
178 * Subtree @local_fixups, which is overlay node __local_fixups__,
179 * mirrors the fragment node structure at the root of the overlay.
180 *
181 * For each property in the fragments that contains a phandle reference,
182 * @local_fixups has a property of the same name that contains a list
183 * of offsets of the phandle reference(s) within the respective property
184 * value(s). The values at these offsets will be fixed up.
185 */
186static int adjust_local_phandle_references(struct device_node *local_fixups,
187 struct device_node *overlay, int phandle_delta)
188{
189 struct device_node *child, *overlay_child;
190 struct property *prop_fix, *prop;
191 int err, i, count;
192 unsigned int off;
193 phandle phandle;
194
195 if (!local_fixups)
196 return 0;
197
198 for_each_property_of_node(local_fixups, prop_fix) {
199
200 /* skip properties added automatically */
201 if (!of_prop_cmp(prop_fix->name, "name") ||
202 !of_prop_cmp(prop_fix->name, "phandle") ||
203 !of_prop_cmp(prop_fix->name, "linux,phandle"))
204 continue;
205
206 if ((prop_fix->length % 4) != 0 || prop_fix->length == 0)
207 return -EINVAL;
208 count = prop_fix->length / sizeof(__be32);
209
210 for_each_property_of_node(overlay, prop) {
211 if (!of_prop_cmp(prop->name, prop_fix->name))
212 break;
213 }
214
215 if (!prop)
216 return -EINVAL;
217
218 for (i = 0; i < count; i++) {
219 off = be32_to_cpu(((__be32 *)prop_fix->value)[i]);
220 if ((off + 4) > prop->length)
221 return -EINVAL;
222
223 phandle = be32_to_cpu(*(__be32 *)(prop->value + off));
224 phandle += phandle_delta;
225 *(__be32 *)(prop->value + off) = cpu_to_be32(phandle);
226 }
227 }
228
229 /*
230 * These nested loops recurse down two subtrees in parallel, where the
231 * node names in the two subtrees match.
232 *
233 * The roots of the subtrees are the overlay's __local_fixups__ node
234 * and the overlay's root node.
235 */
236 for_each_child_of_node(local_fixups, child) {
237
238 for_each_child_of_node(overlay, overlay_child)
239 if (!node_name_cmp(child, overlay_child))
240 break;
241
242 if (!overlay_child)
243 return -EINVAL;
244
245 err = adjust_local_phandle_references(child, overlay_child,
246 phandle_delta);
247 if (err)
248 return err;
249 }
250
251 return 0;
252}
253
254/**
255 * of_resolve_phandles - Relocate and resolve overlay against live tree
256 *
257 * @overlay: Pointer to devicetree overlay to relocate and resolve
258 *
259 * Modify (relocate) values of local phandles in @overlay to a range that
260 * does not conflict with the live expanded devicetree. Update references
261 * to the local phandles in @overlay. Update (resolve) phandle references
262 * in @overlay that refer to the live expanded devicetree.
263 *
264 * Phandle values in the live tree are in the range of
265 * 1 .. live_tree_max_phandle(). The range of phandle values in the overlay
266 * also begin with at 1. Adjust the phandle values in the overlay to begin
267 * at live_tree_max_phandle() + 1. Update references to the phandles to
268 * the adjusted phandle values.
269 *
270 * The name of each property in the "__fixups__" node in the overlay matches
271 * the name of a symbol (a label) in the live tree. The values of each
272 * property in the "__fixups__" node is a list of the property values in the
273 * overlay that need to be updated to contain the phandle reference
274 * corresponding to that symbol in the live tree. Update the references in
275 * the overlay with the phandle values in the live tree.
276 *
277 * @overlay must be detached.
278 *
279 * Resolving and applying @overlay to the live expanded devicetree must be
280 * protected by a mechanism to ensure that multiple overlays are processed
281 * in a single threaded manner so that multiple overlays will not relocate
282 * phandles to overlapping ranges. The mechanism to enforce this is not
283 * yet implemented.
284 *
285 * Return: %0 on success or a negative error value on error.
286 */
287int of_resolve_phandles(struct device_node *overlay)
288{
289 struct device_node *child, *local_fixups, *refnode;
290 struct device_node *tree_symbols, *overlay_fixups;
291 struct property *prop;
292 const char *refpath;
293 phandle phandle, phandle_delta;
294 int err;
295
296 tree_symbols = NULL;
297
298 if (!overlay) {
299 pr_err("null overlay\n");
300 err = -EINVAL;
301 goto out;
302 }
303 if (!of_node_check_flag(overlay, OF_DETACHED)) {
304 pr_err("overlay not detached\n");
305 err = -EINVAL;
306 goto out;
307 }
308
309 phandle_delta = live_tree_max_phandle() + 1;
310 adjust_overlay_phandles(overlay, phandle_delta);
311
312 for_each_child_of_node(overlay, local_fixups)
313 if (!of_node_cmp(local_fixups->name, "__local_fixups__"))
314 break;
315
316 err = adjust_local_phandle_references(local_fixups, overlay, phandle_delta);
317 if (err)
318 goto out;
319
320 overlay_fixups = NULL;
321
322 for_each_child_of_node(overlay, child) {
323 if (!of_node_cmp(child->name, "__fixups__"))
324 overlay_fixups = child;
325 }
326
327 if (!overlay_fixups) {
328 err = 0;
329 goto out;
330 }
331
332 tree_symbols = of_find_node_by_path("/__symbols__");
333 if (!tree_symbols) {
334 pr_err("no symbols in root of device tree.\n");
335 err = -EINVAL;
336 goto out;
337 }
338
339 for_each_property_of_node(overlay_fixups, prop) {
340
341 /* skip properties added automatically */
342 if (!of_prop_cmp(prop->name, "name"))
343 continue;
344
345 err = of_property_read_string(tree_symbols,
346 prop->name, &refpath);
347 if (err)
348 goto out;
349
350 refnode = of_find_node_by_path(refpath);
351 if (!refnode) {
352 err = -ENOENT;
353 goto out;
354 }
355
356 phandle = refnode->phandle;
357 of_node_put(refnode);
358
359 err = update_usages_of_a_phandle_reference(overlay, prop, phandle);
360 if (err)
361 break;
362 }
363
364out:
365 if (err)
366 pr_err("overlay phandle fixup failed: %d\n", err);
367 of_node_put(tree_symbols);
368
369 return err;
370}
371EXPORT_SYMBOL_GPL(of_resolve_phandles);
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);