Commit | Line | Data |
---|---|---|
7941b27b PA |
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 | ||
606ad42a RH |
12 | #define pr_fmt(fmt) "OF: resolver: " fmt |
13 | ||
7941b27b PA |
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> | |
7941b27b PA |
21 | #include <linux/slab.h> |
22 | ||
23 | /* illegal phandle value (set when unresolved) */ | |
24 | #define OF_PHANDLE_ILLEGAL 0xdeadbeef | |
25 | ||
26 | /** | |
27 | * Find a node with the give full name by recursively following any of | |
28 | * the child node links. | |
29 | */ | |
fad556bf | 30 | static struct device_node *find_node_by_full_name(struct device_node *node, |
7941b27b PA |
31 | const char *full_name) |
32 | { | |
33 | struct device_node *child, *found; | |
34 | ||
9f27ede4 | 35 | if (!node) |
7941b27b PA |
36 | return NULL; |
37 | ||
9f27ede4 | 38 | if (!of_node_cmp(node->full_name, full_name)) |
82f68756 | 39 | return of_node_get(node); |
7941b27b PA |
40 | |
41 | for_each_child_of_node(node, child) { | |
fad556bf | 42 | found = find_node_by_full_name(child, full_name); |
82f68756 AKC |
43 | if (found != NULL) { |
44 | of_node_put(child); | |
7941b27b | 45 | return found; |
82f68756 | 46 | } |
7941b27b PA |
47 | } |
48 | ||
49 | return NULL; | |
50 | } | |
51 | ||
f94823f2 | 52 | static phandle live_tree_max_phandle(void) |
7941b27b PA |
53 | { |
54 | struct device_node *node; | |
55 | phandle phandle; | |
56 | unsigned long flags; | |
57 | ||
7941b27b PA |
58 | raw_spin_lock_irqsave(&devtree_lock, flags); |
59 | phandle = 0; | |
60 | for_each_of_allnodes(node) { | |
61 | if (node->phandle != OF_PHANDLE_ILLEGAL && | |
62 | node->phandle > phandle) | |
63 | phandle = node->phandle; | |
64 | } | |
65 | raw_spin_unlock_irqrestore(&devtree_lock, flags); | |
66 | ||
67 | return phandle; | |
68 | } | |
69 | ||
25e16877 | 70 | static void adjust_overlay_phandles(struct device_node *overlay, |
7941b27b PA |
71 | int phandle_delta) |
72 | { | |
73 | struct device_node *child; | |
74 | struct property *prop; | |
75 | phandle phandle; | |
76 | ||
269f1a67 | 77 | /* adjust node's phandle in node */ |
25e16877 FR |
78 | if (overlay->phandle != 0 && overlay->phandle != OF_PHANDLE_ILLEGAL) |
79 | overlay->phandle += phandle_delta; | |
7941b27b | 80 | |
269f1a67 | 81 | /* copy adjusted phandle into *phandle properties */ |
25e16877 | 82 | for_each_property_of_node(overlay, prop) { |
7941b27b | 83 | |
9f27ede4 FR |
84 | if (of_prop_cmp(prop->name, "phandle") && |
85 | of_prop_cmp(prop->name, "linux,phandle")) | |
7941b27b PA |
86 | continue; |
87 | ||
7941b27b PA |
88 | if (prop->length < 4) |
89 | continue; | |
90 | ||
7941b27b | 91 | phandle = be32_to_cpup(prop->value); |
a67976ec | 92 | if (phandle == OF_PHANDLE_ILLEGAL) |
7941b27b PA |
93 | continue; |
94 | ||
25e16877 | 95 | *(uint32_t *)prop->value = cpu_to_be32(overlay->phandle); |
7941b27b PA |
96 | } |
97 | ||
25e16877 | 98 | for_each_child_of_node(overlay, child) |
f94823f2 | 99 | adjust_overlay_phandles(child, phandle_delta); |
7941b27b PA |
100 | } |
101 | ||
25e16877 FR |
102 | static int update_usages_of_a_phandle_reference(struct device_node *overlay, |
103 | struct property *prop_fixup, phandle phandle) | |
7941b27b | 104 | { |
7941b27b | 105 | struct device_node *refnode; |
25e16877 FR |
106 | struct property *prop; |
107 | char *value, *cur, *end, *node_path, *prop_name, *s; | |
108 | int offset, len; | |
7941b27b PA |
109 | int err = 0; |
110 | ||
25e16877 FR |
111 | value = kmalloc(prop_fixup->length, GFP_KERNEL); |
112 | if (!value) | |
7941b27b | 113 | return -ENOMEM; |
25e16877 | 114 | memcpy(value, prop_fixup->value, prop_fixup->length); |
7941b27b | 115 | |
269f1a67 | 116 | /* prop_fixup contains a list of tuples of path:property_name:offset */ |
25e16877 FR |
117 | end = value + prop_fixup->length; |
118 | for (cur = value; cur < end; cur += len + 1) { | |
119 | len = strlen(cur); | |
7941b27b | 120 | |
25e16877 FR |
121 | node_path = cur; |
122 | s = strchr(cur, ':'); | |
7941b27b | 123 | if (!s) { |
7941b27b PA |
124 | err = -EINVAL; |
125 | goto err_fail; | |
126 | } | |
127 | *s++ = '\0'; | |
128 | ||
25e16877 | 129 | prop_name = s; |
7941b27b PA |
130 | s = strchr(s, ':'); |
131 | if (!s) { | |
7941b27b PA |
132 | err = -EINVAL; |
133 | goto err_fail; | |
134 | } | |
7941b27b | 135 | *s++ = '\0'; |
624ab2a4 | 136 | |
7941b27b | 137 | err = kstrtoint(s, 10, &offset); |
9f27ede4 | 138 | if (err) |
7941b27b | 139 | goto err_fail; |
7941b27b | 140 | |
25e16877 | 141 | refnode = find_node_by_full_name(overlay, node_path); |
96d1c8e8 | 142 | if (!refnode) |
7941b27b | 143 | continue; |
7941b27b | 144 | |
25e16877 FR |
145 | for_each_property_of_node(refnode, prop) { |
146 | if (!of_prop_cmp(prop->name, prop_name)) | |
7941b27b PA |
147 | break; |
148 | } | |
82f68756 | 149 | of_node_put(refnode); |
7941b27b | 150 | |
25e16877 | 151 | if (!prop) { |
7941b27b PA |
152 | err = -ENOENT; |
153 | goto err_fail; | |
154 | } | |
155 | ||
25e16877 | 156 | *(__be32 *)(prop->value + offset) = cpu_to_be32(phandle); |
7941b27b PA |
157 | } |
158 | ||
159 | err_fail: | |
25e16877 | 160 | kfree(value); |
7941b27b PA |
161 | return err; |
162 | } | |
163 | ||
da56d04c | 164 | /* compare nodes taking into account that 'name' strips out the @ part */ |
fad556bf | 165 | static int node_name_cmp(const struct device_node *dn1, |
da56d04c PA |
166 | const struct device_node *dn2) |
167 | { | |
168 | const char *n1 = strrchr(dn1->full_name, '/') ? : "/"; | |
169 | const char *n2 = strrchr(dn2->full_name, '/') ? : "/"; | |
170 | ||
171 | return of_node_cmp(n1, n2); | |
172 | } | |
173 | ||
7941b27b PA |
174 | /* |
175 | * Adjust the local phandle references by the given phandle delta. | |
269f1a67 FR |
176 | * |
177 | * Subtree @local_fixups, which is overlay node __local_fixups__, | |
178 | * mirrors the fragment node structure at the root of the overlay. | |
179 | * | |
180 | * For each property in the fragments that contains a phandle reference, | |
181 | * @local_fixups has a property of the same name that contains a list | |
182 | * of offsets of the phandle reference(s) within the respective property | |
183 | * value(s). The values at these offsets will be fixed up. | |
7941b27b | 184 | */ |
25e16877 FR |
185 | static int adjust_local_phandle_references(struct device_node *local_fixups, |
186 | struct device_node *overlay, int phandle_delta) | |
7941b27b | 187 | { |
25e16877 FR |
188 | struct device_node *child, *overlay_child; |
189 | struct property *prop_fix, *prop; | |
da56d04c PA |
190 | int err, i, count; |
191 | unsigned int off; | |
192 | phandle phandle; | |
7941b27b | 193 | |
25e16877 | 194 | if (!local_fixups) |
7941b27b PA |
195 | return 0; |
196 | ||
25e16877 | 197 | for_each_property_of_node(local_fixups, prop_fix) { |
da56d04c | 198 | |
7941b27b | 199 | /* skip properties added automatically */ |
25e16877 FR |
200 | if (!of_prop_cmp(prop_fix->name, "name") || |
201 | !of_prop_cmp(prop_fix->name, "phandle") || | |
202 | !of_prop_cmp(prop_fix->name, "linux,phandle")) | |
7941b27b PA |
203 | continue; |
204 | ||
25e16877 | 205 | if ((prop_fix->length % 4) != 0 || prop_fix->length == 0) |
da56d04c | 206 | return -EINVAL; |
25e16877 | 207 | count = prop_fix->length / sizeof(__be32); |
da56d04c | 208 | |
25e16877 FR |
209 | for_each_property_of_node(overlay, prop) { |
210 | if (!of_prop_cmp(prop->name, prop_fix->name)) | |
da56d04c PA |
211 | break; |
212 | } | |
213 | ||
25e16877 | 214 | if (!prop) |
da56d04c | 215 | return -EINVAL; |
da56d04c PA |
216 | |
217 | for (i = 0; i < count; i++) { | |
25e16877 | 218 | off = be32_to_cpu(((__be32 *)prop_fix->value)[i]); |
ea8229b7 | 219 | if ((off + 4) > prop->length) |
da56d04c | 220 | return -EINVAL; |
da56d04c | 221 | |
624ab2a4 FR |
222 | phandle = be32_to_cpu(*(__be32 *)(prop->value + off)); |
223 | phandle += phandle_delta; | |
224 | *(__be32 *)(prop->value + off) = cpu_to_be32(phandle); | |
da56d04c PA |
225 | } |
226 | } | |
227 | ||
269f1a67 FR |
228 | /* |
229 | * These nested loops recurse down two subtrees in parallel, where the | |
230 | * node names in the two subtrees match. | |
231 | * | |
232 | * The roots of the subtrees are the overlay's __local_fixups__ node | |
233 | * and the overlay's root node. | |
234 | */ | |
25e16877 | 235 | for_each_child_of_node(local_fixups, child) { |
da56d04c | 236 | |
25e16877 FR |
237 | for_each_child_of_node(overlay, overlay_child) |
238 | if (!node_name_cmp(child, overlay_child)) | |
da56d04c PA |
239 | break; |
240 | ||
25e16877 | 241 | if (!overlay_child) |
da56d04c | 242 | return -EINVAL; |
da56d04c | 243 | |
25e16877 | 244 | err = adjust_local_phandle_references(child, overlay_child, |
da56d04c | 245 | phandle_delta); |
9f27ede4 | 246 | if (err) |
7941b27b PA |
247 | return err; |
248 | } | |
249 | ||
250 | return 0; | |
251 | } | |
252 | ||
253 | /** | |
269f1a67 FR |
254 | * of_resolve_phandles - Relocate and resolve overlay against live tree |
255 | * | |
256 | * @overlay: Pointer to devicetree overlay to relocate and resolve | |
257 | * | |
258 | * Modify (relocate) values of local phandles in @overlay to a range that | |
259 | * does not conflict with the live expanded devicetree. Update references | |
260 | * to the local phandles in @overlay. Update (resolve) phandle references | |
261 | * in @overlay that refer to the live expanded devicetree. | |
262 | * | |
263 | * Phandle values in the live tree are in the range of | |
264 | * 1 .. live_tree_max_phandle(). The range of phandle values in the overlay | |
265 | * also begin with at 1. Adjust the phandle values in the overlay to begin | |
266 | * at live_tree_max_phandle() + 1. Update references to the phandles to | |
267 | * the adjusted phandle values. | |
268 | * | |
269 | * The name of each property in the "__fixups__" node in the overlay matches | |
270 | * the name of a symbol (a label) in the live tree. The values of each | |
271 | * property in the "__fixups__" node is a list of the property values in the | |
272 | * overlay that need to be updated to contain the phandle reference | |
273 | * corresponding to that symbol in the live tree. Update the references in | |
274 | * the overlay with the phandle values in the live tree. | |
275 | * | |
276 | * @overlay must be detached. | |
7941b27b | 277 | * |
269f1a67 FR |
278 | * Resolving and applying @overlay to the live expanded devicetree must be |
279 | * protected by a mechanism to ensure that multiple overlays are processed | |
280 | * in a single threaded manner so that multiple overlays will not relocate | |
281 | * phandles to overlapping ranges. The mechanism to enforce this is not | |
282 | * yet implemented. | |
7941b27b | 283 | * |
269f1a67 | 284 | * Return: %0 on success or a negative error value on error. |
7941b27b | 285 | */ |
25e16877 | 286 | int of_resolve_phandles(struct device_node *overlay) |
7941b27b | 287 | { |
25e16877 | 288 | struct device_node *child, *local_fixups, *refnode; |
5581a95f | 289 | struct device_node *tree_symbols, *overlay_fixups; |
25e16877 | 290 | struct property *prop; |
7941b27b PA |
291 | const char *refpath; |
292 | phandle phandle, phandle_delta; | |
293 | int err; | |
294 | ||
d9181b20 FR |
295 | tree_symbols = NULL; |
296 | ||
624ab2a4 FR |
297 | if (!overlay) { |
298 | pr_err("null overlay\n"); | |
d9181b20 | 299 | err = -EINVAL; |
32bed310 | 300 | goto out; |
624ab2a4 FR |
301 | } |
302 | if (!of_node_check_flag(overlay, OF_DETACHED)) { | |
303 | pr_err("overlay not detached\n"); | |
d9181b20 | 304 | err = -EINVAL; |
32bed310 | 305 | goto out; |
624ab2a4 | 306 | } |
7941b27b | 307 | |
f94823f2 | 308 | phandle_delta = live_tree_max_phandle() + 1; |
25e16877 | 309 | adjust_overlay_phandles(overlay, phandle_delta); |
da56d04c | 310 | |
25e16877 FR |
311 | for_each_child_of_node(overlay, local_fixups) |
312 | if (!of_node_cmp(local_fixups->name, "__local_fixups__")) | |
da56d04c PA |
313 | break; |
314 | ||
624ab2a4 FR |
315 | err = adjust_local_phandle_references(local_fixups, overlay, phandle_delta); |
316 | if (err) | |
32bed310 | 317 | goto out; |
da56d04c | 318 | |
25e16877 | 319 | overlay_fixups = NULL; |
7941b27b | 320 | |
25e16877 | 321 | for_each_child_of_node(overlay, child) { |
624ab2a4 | 322 | if (!of_node_cmp(child->name, "__fixups__")) |
25e16877 | 323 | overlay_fixups = child; |
7941b27b PA |
324 | } |
325 | ||
25e16877 | 326 | if (!overlay_fixups) { |
a67976ec | 327 | err = 0; |
7941b27b PA |
328 | goto out; |
329 | } | |
330 | ||
4458db4c | 331 | tree_symbols = of_find_node_by_path("/__symbols__"); |
25e16877 | 332 | if (!tree_symbols) { |
624ab2a4 | 333 | pr_err("no symbols in root of device tree.\n"); |
7941b27b | 334 | err = -EINVAL; |
32bed310 | 335 | goto out; |
7941b27b PA |
336 | } |
337 | ||
25e16877 | 338 | for_each_property_of_node(overlay_fixups, prop) { |
7941b27b PA |
339 | |
340 | /* skip properties added automatically */ | |
25e16877 | 341 | if (!of_prop_cmp(prop->name, "name")) |
7941b27b PA |
342 | continue; |
343 | ||
25e16877 FR |
344 | err = of_property_read_string(tree_symbols, |
345 | prop->name, &refpath); | |
9f27ede4 | 346 | if (err) |
32bed310 | 347 | goto out; |
7941b27b PA |
348 | |
349 | refnode = of_find_node_by_path(refpath); | |
350 | if (!refnode) { | |
7941b27b | 351 | err = -ENOENT; |
32bed310 | 352 | goto out; |
7941b27b PA |
353 | } |
354 | ||
355 | phandle = refnode->phandle; | |
356 | of_node_put(refnode); | |
357 | ||
25e16877 | 358 | err = update_usages_of_a_phandle_reference(overlay, prop, phandle); |
7941b27b PA |
359 | if (err) |
360 | break; | |
361 | } | |
362 | ||
363 | out: | |
32bed310 MF |
364 | if (err) |
365 | pr_err("overlay phandle fixup failed: %d\n", err); | |
25e16877 | 366 | of_node_put(tree_symbols); |
7941b27b PA |
367 | |
368 | return err; | |
369 | } | |
370 | EXPORT_SYMBOL_GPL(of_resolve_phandles); |