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af6074fc | 1 | // SPDX-License-Identifier: GPL-2.0 |
7941b27b PA |
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. | |
7941b27b PA |
7 | */ |
8 | ||
606ad42a RH |
9 | #define pr_fmt(fmt) "OF: resolver: " fmt |
10 | ||
7941b27b PA |
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> | |
7941b27b PA |
18 | #include <linux/slab.h> |
19 | ||
27497e11 RH |
20 | #include "of_private.h" |
21 | ||
f94823f2 | 22 | static phandle live_tree_max_phandle(void) |
7941b27b PA |
23 | { |
24 | struct device_node *node; | |
25 | phandle phandle; | |
26 | unsigned long flags; | |
27 | ||
7941b27b PA |
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 | ||
25e16877 | 40 | static void adjust_overlay_phandles(struct device_node *overlay, |
7941b27b PA |
41 | int phandle_delta) |
42 | { | |
43 | struct device_node *child; | |
44 | struct property *prop; | |
45 | phandle phandle; | |
46 | ||
269f1a67 | 47 | /* adjust node's phandle in node */ |
25e16877 FR |
48 | if (overlay->phandle != 0 && overlay->phandle != OF_PHANDLE_ILLEGAL) |
49 | overlay->phandle += phandle_delta; | |
7941b27b | 50 | |
269f1a67 | 51 | /* copy adjusted phandle into *phandle properties */ |
25e16877 | 52 | for_each_property_of_node(overlay, prop) { |
7941b27b | 53 | |
9f27ede4 FR |
54 | if (of_prop_cmp(prop->name, "phandle") && |
55 | of_prop_cmp(prop->name, "linux,phandle")) | |
7941b27b PA |
56 | continue; |
57 | ||
7941b27b PA |
58 | if (prop->length < 4) |
59 | continue; | |
60 | ||
7941b27b | 61 | phandle = be32_to_cpup(prop->value); |
a67976ec | 62 | if (phandle == OF_PHANDLE_ILLEGAL) |
7941b27b PA |
63 | continue; |
64 | ||
17a70355 | 65 | *(__be32 *)prop->value = cpu_to_be32(overlay->phandle); |
7941b27b PA |
66 | } |
67 | ||
25e16877 | 68 | for_each_child_of_node(overlay, child) |
f94823f2 | 69 | adjust_overlay_phandles(child, phandle_delta); |
7941b27b PA |
70 | } |
71 | ||
25e16877 FR |
72 | static int update_usages_of_a_phandle_reference(struct device_node *overlay, |
73 | struct property *prop_fixup, phandle phandle) | |
7941b27b | 74 | { |
7941b27b | 75 | struct device_node *refnode; |
25e16877 FR |
76 | struct property *prop; |
77 | char *value, *cur, *end, *node_path, *prop_name, *s; | |
78 | int offset, len; | |
7941b27b PA |
79 | int err = 0; |
80 | ||
eeb09506 | 81 | value = kmemdup(prop_fixup->value, prop_fixup->length, GFP_KERNEL); |
25e16877 | 82 | if (!value) |
7941b27b | 83 | return -ENOMEM; |
7941b27b | 84 | |
269f1a67 | 85 | /* prop_fixup contains a list of tuples of path:property_name:offset */ |
25e16877 FR |
86 | end = value + prop_fixup->length; |
87 | for (cur = value; cur < end; cur += len + 1) { | |
88 | len = strlen(cur); | |
7941b27b | 89 | |
25e16877 FR |
90 | node_path = cur; |
91 | s = strchr(cur, ':'); | |
7941b27b | 92 | if (!s) { |
7941b27b PA |
93 | err = -EINVAL; |
94 | goto err_fail; | |
95 | } | |
96 | *s++ = '\0'; | |
97 | ||
25e16877 | 98 | prop_name = s; |
7941b27b PA |
99 | s = strchr(s, ':'); |
100 | if (!s) { | |
7941b27b PA |
101 | err = -EINVAL; |
102 | goto err_fail; | |
103 | } | |
7941b27b | 104 | *s++ = '\0'; |
624ab2a4 | 105 | |
7941b27b | 106 | err = kstrtoint(s, 10, &offset); |
9f27ede4 | 107 | if (err) |
7941b27b | 108 | goto err_fail; |
7941b27b | 109 | |
27497e11 | 110 | refnode = __of_find_node_by_full_path(of_node_get(overlay), node_path); |
96d1c8e8 | 111 | if (!refnode) |
7941b27b | 112 | continue; |
7941b27b | 113 | |
25e16877 FR |
114 | for_each_property_of_node(refnode, prop) { |
115 | if (!of_prop_cmp(prop->name, prop_name)) | |
7941b27b PA |
116 | break; |
117 | } | |
82f68756 | 118 | of_node_put(refnode); |
7941b27b | 119 | |
25e16877 | 120 | if (!prop) { |
7941b27b PA |
121 | err = -ENOENT; |
122 | goto err_fail; | |
123 | } | |
124 | ||
482137bf FR |
125 | if (offset < 0 || offset + sizeof(__be32) > prop->length) { |
126 | err = -EINVAL; | |
127 | goto err_fail; | |
128 | } | |
129 | ||
25e16877 | 130 | *(__be32 *)(prop->value + offset) = cpu_to_be32(phandle); |
7941b27b PA |
131 | } |
132 | ||
133 | err_fail: | |
25e16877 | 134 | kfree(value); |
7941b27b PA |
135 | return err; |
136 | } | |
137 | ||
da56d04c | 138 | /* compare nodes taking into account that 'name' strips out the @ part */ |
fad556bf | 139 | static int node_name_cmp(const struct device_node *dn1, |
da56d04c PA |
140 | const struct device_node *dn2) |
141 | { | |
95e6b1fa RH |
142 | const char *n1 = kbasename(dn1->full_name); |
143 | const char *n2 = kbasename(dn2->full_name); | |
da56d04c PA |
144 | |
145 | return of_node_cmp(n1, n2); | |
146 | } | |
147 | ||
7941b27b PA |
148 | /* |
149 | * Adjust the local phandle references by the given phandle delta. | |
269f1a67 FR |
150 | * |
151 | * Subtree @local_fixups, which is overlay node __local_fixups__, | |
152 | * mirrors the fragment node structure at the root of the overlay. | |
153 | * | |
154 | * For each property in the fragments that contains a phandle reference, | |
155 | * @local_fixups has a property of the same name that contains a list | |
156 | * of offsets of the phandle reference(s) within the respective property | |
157 | * value(s). The values at these offsets will be fixed up. | |
7941b27b | 158 | */ |
25e16877 FR |
159 | static int adjust_local_phandle_references(struct device_node *local_fixups, |
160 | struct device_node *overlay, int phandle_delta) | |
7941b27b | 161 | { |
25e16877 FR |
162 | struct device_node *child, *overlay_child; |
163 | struct property *prop_fix, *prop; | |
da56d04c PA |
164 | int err, i, count; |
165 | unsigned int off; | |
7941b27b | 166 | |
25e16877 | 167 | if (!local_fixups) |
7941b27b PA |
168 | return 0; |
169 | ||
25e16877 | 170 | for_each_property_of_node(local_fixups, prop_fix) { |
da56d04c | 171 | |
7941b27b | 172 | /* skip properties added automatically */ |
25e16877 FR |
173 | if (!of_prop_cmp(prop_fix->name, "name") || |
174 | !of_prop_cmp(prop_fix->name, "phandle") || | |
175 | !of_prop_cmp(prop_fix->name, "linux,phandle")) | |
7941b27b PA |
176 | continue; |
177 | ||
25e16877 | 178 | if ((prop_fix->length % 4) != 0 || prop_fix->length == 0) |
da56d04c | 179 | return -EINVAL; |
25e16877 | 180 | count = prop_fix->length / sizeof(__be32); |
da56d04c | 181 | |
25e16877 FR |
182 | for_each_property_of_node(overlay, prop) { |
183 | if (!of_prop_cmp(prop->name, prop_fix->name)) | |
da56d04c PA |
184 | break; |
185 | } | |
186 | ||
25e16877 | 187 | if (!prop) |
da56d04c | 188 | return -EINVAL; |
da56d04c PA |
189 | |
190 | for (i = 0; i < count; i++) { | |
25e16877 | 191 | off = be32_to_cpu(((__be32 *)prop_fix->value)[i]); |
ea8229b7 | 192 | if ((off + 4) > prop->length) |
da56d04c | 193 | return -EINVAL; |
da56d04c | 194 | |
d35d623f | 195 | be32_add_cpu(prop->value + off, phandle_delta); |
da56d04c PA |
196 | } |
197 | } | |
198 | ||
269f1a67 FR |
199 | /* |
200 | * These nested loops recurse down two subtrees in parallel, where the | |
201 | * node names in the two subtrees match. | |
202 | * | |
203 | * The roots of the subtrees are the overlay's __local_fixups__ node | |
204 | * and the overlay's root node. | |
205 | */ | |
25e16877 | 206 | for_each_child_of_node(local_fixups, child) { |
da56d04c | 207 | |
25e16877 | 208 | for_each_child_of_node(overlay, overlay_child) |
60d437bb ND |
209 | if (!node_name_cmp(child, overlay_child)) { |
210 | of_node_put(overlay_child); | |
da56d04c | 211 | break; |
60d437bb | 212 | } |
da56d04c | 213 | |
60d437bb ND |
214 | if (!overlay_child) { |
215 | of_node_put(child); | |
da56d04c | 216 | return -EINVAL; |
60d437bb | 217 | } |
da56d04c | 218 | |
25e16877 | 219 | err = adjust_local_phandle_references(child, overlay_child, |
da56d04c | 220 | phandle_delta); |
60d437bb ND |
221 | if (err) { |
222 | of_node_put(child); | |
7941b27b | 223 | return err; |
60d437bb | 224 | } |
7941b27b PA |
225 | } |
226 | ||
227 | return 0; | |
228 | } | |
229 | ||
230 | /** | |
269f1a67 FR |
231 | * of_resolve_phandles - Relocate and resolve overlay against live tree |
232 | * | |
233 | * @overlay: Pointer to devicetree overlay to relocate and resolve | |
234 | * | |
235 | * Modify (relocate) values of local phandles in @overlay to a range that | |
236 | * does not conflict with the live expanded devicetree. Update references | |
237 | * to the local phandles in @overlay. Update (resolve) phandle references | |
238 | * in @overlay that refer to the live expanded devicetree. | |
239 | * | |
240 | * Phandle values in the live tree are in the range of | |
241 | * 1 .. live_tree_max_phandle(). The range of phandle values in the overlay | |
242 | * also begin with at 1. Adjust the phandle values in the overlay to begin | |
243 | * at live_tree_max_phandle() + 1. Update references to the phandles to | |
244 | * the adjusted phandle values. | |
245 | * | |
246 | * The name of each property in the "__fixups__" node in the overlay matches | |
247 | * the name of a symbol (a label) in the live tree. The values of each | |
248 | * property in the "__fixups__" node is a list of the property values in the | |
249 | * overlay that need to be updated to contain the phandle reference | |
250 | * corresponding to that symbol in the live tree. Update the references in | |
251 | * the overlay with the phandle values in the live tree. | |
252 | * | |
253 | * @overlay must be detached. | |
7941b27b | 254 | * |
269f1a67 FR |
255 | * Resolving and applying @overlay to the live expanded devicetree must be |
256 | * protected by a mechanism to ensure that multiple overlays are processed | |
257 | * in a single threaded manner so that multiple overlays will not relocate | |
258 | * phandles to overlapping ranges. The mechanism to enforce this is not | |
259 | * yet implemented. | |
7941b27b | 260 | * |
269f1a67 | 261 | * Return: %0 on success or a negative error value on error. |
7941b27b | 262 | */ |
25e16877 | 263 | int of_resolve_phandles(struct device_node *overlay) |
7941b27b | 264 | { |
25e16877 | 265 | struct device_node *child, *local_fixups, *refnode; |
5581a95f | 266 | struct device_node *tree_symbols, *overlay_fixups; |
25e16877 | 267 | struct property *prop; |
7941b27b PA |
268 | const char *refpath; |
269 | phandle phandle, phandle_delta; | |
270 | int err; | |
271 | ||
d9181b20 FR |
272 | tree_symbols = NULL; |
273 | ||
624ab2a4 FR |
274 | if (!overlay) { |
275 | pr_err("null overlay\n"); | |
d9181b20 | 276 | err = -EINVAL; |
32bed310 | 277 | goto out; |
624ab2a4 | 278 | } |
f948d6d8 | 279 | |
624ab2a4 FR |
280 | if (!of_node_check_flag(overlay, OF_DETACHED)) { |
281 | pr_err("overlay not detached\n"); | |
d9181b20 | 282 | err = -EINVAL; |
32bed310 | 283 | goto out; |
624ab2a4 | 284 | } |
7941b27b | 285 | |
f94823f2 | 286 | phandle_delta = live_tree_max_phandle() + 1; |
25e16877 | 287 | adjust_overlay_phandles(overlay, phandle_delta); |
da56d04c | 288 | |
25e16877 | 289 | for_each_child_of_node(overlay, local_fixups) |
b3e46d1a | 290 | if (of_node_name_eq(local_fixups, "__local_fixups__")) |
da56d04c PA |
291 | break; |
292 | ||
624ab2a4 FR |
293 | err = adjust_local_phandle_references(local_fixups, overlay, phandle_delta); |
294 | if (err) | |
32bed310 | 295 | goto out; |
da56d04c | 296 | |
25e16877 | 297 | overlay_fixups = NULL; |
7941b27b | 298 | |
25e16877 | 299 | for_each_child_of_node(overlay, child) { |
b3e46d1a | 300 | if (of_node_name_eq(child, "__fixups__")) |
25e16877 | 301 | overlay_fixups = child; |
7941b27b PA |
302 | } |
303 | ||
25e16877 | 304 | if (!overlay_fixups) { |
a67976ec | 305 | err = 0; |
7941b27b PA |
306 | goto out; |
307 | } | |
308 | ||
4458db4c | 309 | tree_symbols = of_find_node_by_path("/__symbols__"); |
25e16877 | 310 | if (!tree_symbols) { |
624ab2a4 | 311 | pr_err("no symbols in root of device tree.\n"); |
7941b27b | 312 | err = -EINVAL; |
32bed310 | 313 | goto out; |
7941b27b PA |
314 | } |
315 | ||
25e16877 | 316 | for_each_property_of_node(overlay_fixups, prop) { |
7941b27b PA |
317 | |
318 | /* skip properties added automatically */ | |
25e16877 | 319 | if (!of_prop_cmp(prop->name, "name")) |
7941b27b PA |
320 | continue; |
321 | ||
25e16877 FR |
322 | err = of_property_read_string(tree_symbols, |
323 | prop->name, &refpath); | |
a3958323 LC |
324 | if (err) { |
325 | pr_err("node label '%s' not found in live devicetree symbols table\n", | |
326 | prop->name); | |
32bed310 | 327 | goto out; |
a3958323 | 328 | } |
7941b27b PA |
329 | |
330 | refnode = of_find_node_by_path(refpath); | |
331 | if (!refnode) { | |
7941b27b | 332 | err = -ENOENT; |
32bed310 | 333 | goto out; |
7941b27b PA |
334 | } |
335 | ||
336 | phandle = refnode->phandle; | |
337 | of_node_put(refnode); | |
338 | ||
25e16877 | 339 | err = update_usages_of_a_phandle_reference(overlay, prop, phandle); |
7941b27b PA |
340 | if (err) |
341 | break; | |
342 | } | |
343 | ||
344 | out: | |
32bed310 MF |
345 | if (err) |
346 | pr_err("overlay phandle fixup failed: %d\n", err); | |
25e16877 | 347 | of_node_put(tree_symbols); |
7941b27b PA |
348 | |
349 | return err; | |
350 | } | |
351 | EXPORT_SYMBOL_GPL(of_resolve_phandles); |