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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - drivers/of/resolver.c
2 * Functions for dealing with DT resolution
4 * Copyright (C) 2012 Pantelis Antoniou <panto@antoniou-consulting.com>
5 * Copyright (C) 2012 Texas Instruments Inc.
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.
12 #define pr_fmt(fmt) "OF: resolver: " fmt
14 #include <linux/kernel.h>
15 #include <linux/module.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/slab.h>
23 /* illegal phandle value (set when unresolved) */
24 #define OF_PHANDLE_ILLEGAL 0xdeadbeef
27 * Find a node with the give full name by recursively following any of
28 * the child node links.
30 static struct device_node
*find_node_by_full_name(struct device_node
*node
,
31 const char *full_name
)
33 struct device_node
*child
, *found
;
38 if (!of_node_cmp(node
->full_name
, full_name
))
39 return of_node_get(node
);
41 for_each_child_of_node(node
, child
) {
42 found
= find_node_by_full_name(child
, full_name
);
52 static phandle
live_tree_max_phandle(void)
54 struct device_node
*node
;
58 raw_spin_lock_irqsave(&devtree_lock
, flags
);
60 for_each_of_allnodes(node
) {
61 if (node
->phandle
!= OF_PHANDLE_ILLEGAL
&&
62 node
->phandle
> phandle
)
63 phandle
= node
->phandle
;
65 raw_spin_unlock_irqrestore(&devtree_lock
, flags
);
70 static void adjust_overlay_phandles(struct device_node
*overlay
,
73 struct device_node
*child
;
74 struct property
*prop
;
77 /* adjust node's phandle in node */
78 if (overlay
->phandle
!= 0 && overlay
->phandle
!= OF_PHANDLE_ILLEGAL
)
79 overlay
->phandle
+= phandle_delta
;
81 /* copy adjusted phandle into *phandle properties */
82 for_each_property_of_node(overlay
, prop
) {
84 if (of_prop_cmp(prop
->name
, "phandle") &&
85 of_prop_cmp(prop
->name
, "linux,phandle"))
91 phandle
= be32_to_cpup(prop
->value
);
92 if (phandle
== OF_PHANDLE_ILLEGAL
)
95 *(__be32
*)prop
->value
= cpu_to_be32(overlay
->phandle
);
98 for_each_child_of_node(overlay
, child
)
99 adjust_overlay_phandles(child
, phandle_delta
);
102 static int update_usages_of_a_phandle_reference(struct device_node
*overlay
,
103 struct property
*prop_fixup
, phandle phandle
)
105 struct device_node
*refnode
;
106 struct property
*prop
;
107 char *value
, *cur
, *end
, *node_path
, *prop_name
, *s
;
111 value
= kmalloc(prop_fixup
->length
, GFP_KERNEL
);
114 memcpy(value
, prop_fixup
->value
, prop_fixup
->length
);
116 /* prop_fixup contains a list of tuples of path:property_name:offset */
117 end
= value
+ prop_fixup
->length
;
118 for (cur
= value
; cur
< end
; cur
+= len
+ 1) {
122 s
= strchr(cur
, ':');
137 err
= kstrtoint(s
, 10, &offset
);
141 refnode
= find_node_by_full_name(overlay
, node_path
);
145 for_each_property_of_node(refnode
, prop
) {
146 if (!of_prop_cmp(prop
->name
, prop_name
))
149 of_node_put(refnode
);
156 *(__be32
*)(prop
->value
+ offset
) = cpu_to_be32(phandle
);
164 /* compare nodes taking into account that 'name' strips out the @ part */
165 static int node_name_cmp(const struct device_node
*dn1
,
166 const struct device_node
*dn2
)
168 const char *n1
= strrchr(dn1
->full_name
, '/') ? : "/";
169 const char *n2
= strrchr(dn2
->full_name
, '/') ? : "/";
171 return of_node_cmp(n1
, n2
);
175 * Adjust the local phandle references by the given phandle delta.
177 * Subtree @local_fixups, which is overlay node __local_fixups__,
178 * mirrors the fragment node structure at the root of the overlay.
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.
185 static int adjust_local_phandle_references(struct device_node
*local_fixups
,
186 struct device_node
*overlay
, int phandle_delta
)
188 struct device_node
*child
, *overlay_child
;
189 struct property
*prop_fix
, *prop
;
197 for_each_property_of_node(local_fixups
, prop_fix
) {
199 /* skip properties added automatically */
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"))
205 if ((prop_fix
->length
% 4) != 0 || prop_fix
->length
== 0)
207 count
= prop_fix
->length
/ sizeof(__be32
);
209 for_each_property_of_node(overlay
, prop
) {
210 if (!of_prop_cmp(prop
->name
, prop_fix
->name
))
217 for (i
= 0; i
< count
; i
++) {
218 off
= be32_to_cpu(((__be32
*)prop_fix
->value
)[i
]);
219 if ((off
+ 4) > prop
->length
)
222 phandle
= be32_to_cpu(*(__be32
*)(prop
->value
+ off
));
223 phandle
+= phandle_delta
;
224 *(__be32
*)(prop
->value
+ off
) = cpu_to_be32(phandle
);
229 * These nested loops recurse down two subtrees in parallel, where the
230 * node names in the two subtrees match.
232 * The roots of the subtrees are the overlay's __local_fixups__ node
233 * and the overlay's root node.
235 for_each_child_of_node(local_fixups
, child
) {
237 for_each_child_of_node(overlay
, overlay_child
)
238 if (!node_name_cmp(child
, overlay_child
))
244 err
= adjust_local_phandle_references(child
, overlay_child
,
254 * of_resolve_phandles - Relocate and resolve overlay against live tree
256 * @overlay: Pointer to devicetree overlay to relocate and resolve
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.
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.
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.
276 * @overlay must be detached.
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
284 * Return: %0 on success or a negative error value on error.
286 int of_resolve_phandles(struct device_node
*overlay
)
288 struct device_node
*child
, *local_fixups
, *refnode
;
289 struct device_node
*tree_symbols
, *overlay_fixups
;
290 struct property
*prop
;
292 phandle phandle
, phandle_delta
;
298 pr_err("null overlay\n");
302 if (!of_node_check_flag(overlay
, OF_DETACHED
)) {
303 pr_err("overlay not detached\n");
308 phandle_delta
= live_tree_max_phandle() + 1;
309 adjust_overlay_phandles(overlay
, phandle_delta
);
311 for_each_child_of_node(overlay
, local_fixups
)
312 if (!of_node_cmp(local_fixups
->name
, "__local_fixups__"))
315 err
= adjust_local_phandle_references(local_fixups
, overlay
, phandle_delta
);
319 overlay_fixups
= NULL
;
321 for_each_child_of_node(overlay
, child
) {
322 if (!of_node_cmp(child
->name
, "__fixups__"))
323 overlay_fixups
= child
;
326 if (!overlay_fixups
) {
331 tree_symbols
= of_find_node_by_path("/__symbols__");
333 pr_err("no symbols in root of device tree.\n");
338 for_each_property_of_node(overlay_fixups
, prop
) {
340 /* skip properties added automatically */
341 if (!of_prop_cmp(prop
->name
, "name"))
344 err
= of_property_read_string(tree_symbols
,
345 prop
->name
, &refpath
);
349 refnode
= of_find_node_by_path(refpath
);
355 phandle
= refnode
->phandle
;
356 of_node_put(refnode
);
358 err
= update_usages_of_a_phandle_reference(overlay
, prop
, phandle
);
365 pr_err("overlay phandle fixup failed: %d\n", err
);
366 of_node_put(tree_symbols
);
370 EXPORT_SYMBOL_GPL(of_resolve_phandles
);