1 #include "libfdt_env.h"
6 #include "libfdt_internal.h"
9 * overlay_get_target_phandle - retrieves the target phandle of a fragment
10 * @fdto: pointer to the device tree overlay blob
11 * @fragment: node offset of the fragment in the overlay
13 * overlay_get_target_phandle() retrieves the target phandle of an
14 * overlay fragment when that fragment uses a phandle (target
15 * property) instead of a path (target-path property).
18 * the phandle pointed by the target property
19 * 0, if the phandle was not found
20 * -1, if the phandle was malformed
22 static uint32_t overlay_get_target_phandle(const void *fdto, int fragment)
27 val = fdt_getprop(fdto, fragment, "target", &len);
31 if ((len != sizeof(*val)) || (*val == (uint32_t)-1))
34 return fdt32_to_cpu(*val);
38 * overlay_get_target - retrieves the offset of a fragment's target
39 * @fdt: Base device tree blob
40 * @fdto: Device tree overlay blob
41 * @fragment: node offset of the fragment in the overlay
43 * overlay_get_target() retrieves the target offset in the base
44 * device tree of a fragment, no matter how the actual targetting is
45 * done (through a phandle or a path)
48 * the targetted node offset in the base device tree
49 * Negative error code on error
51 static int overlay_get_target(const void *fdt, const void *fdto,
58 /* Try first to do a phandle based lookup */
59 phandle = overlay_get_target_phandle(fdto, fragment);
60 if (phandle == (uint32_t)-1)
61 return -FDT_ERR_BADPHANDLE;
64 return fdt_node_offset_by_phandle(fdt, phandle);
66 /* And then a path based lookup */
67 path = fdt_getprop(fdto, fragment, "target-path", &path_len);
70 * If we haven't found either a target or a
71 * target-path property in a node that contains a
72 * __overlay__ subnode (we wouldn't be called
73 * otherwise), consider it a improperly written
76 if (path_len == -FDT_ERR_NOTFOUND)
77 return -FDT_ERR_BADOVERLAY;
82 return fdt_path_offset(fdt, path);
86 * overlay_phandle_add_offset - Increases a phandle by an offset
87 * @fdt: Base device tree blob
88 * @node: Device tree overlay blob
89 * @name: Name of the property to modify (phandle or linux,phandle)
90 * @delta: offset to apply
92 * overlay_phandle_add_offset() increments a node phandle by a given
97 * Negative error code on error
99 static int overlay_phandle_add_offset(void *fdt, int node,
100 const char *name, uint32_t delta)
106 val = fdt_getprop(fdt, node, name, &len);
110 if (len != sizeof(*val))
111 return -FDT_ERR_BADPHANDLE;
113 adj_val = fdt32_to_cpu(*val);
114 if ((adj_val + delta) < adj_val)
115 return -FDT_ERR_NOPHANDLES;
118 if (adj_val == (uint32_t)-1)
119 return -FDT_ERR_NOPHANDLES;
121 return fdt_setprop_inplace_u32(fdt, node, name, adj_val);
125 * overlay_adjust_node_phandles - Offsets the phandles of a node
126 * @fdto: Device tree overlay blob
127 * @node: Offset of the node we want to adjust
128 * @delta: Offset to shift the phandles of
130 * overlay_adjust_node_phandles() adds a constant to all the phandles
131 * of a given node. This is mainly use as part of the overlay
132 * application process, when we want to update all the overlay
133 * phandles to not conflict with the overlays of the base device tree.
137 * Negative error code on failure
139 static int overlay_adjust_node_phandles(void *fdto, int node,
145 ret = overlay_phandle_add_offset(fdto, node, "phandle", delta);
146 if (ret && ret != -FDT_ERR_NOTFOUND)
149 ret = overlay_phandle_add_offset(fdto, node, "linux,phandle", delta);
150 if (ret && ret != -FDT_ERR_NOTFOUND)
153 fdt_for_each_subnode(child, fdto, node) {
154 ret = overlay_adjust_node_phandles(fdto, child, delta);
163 * overlay_adjust_local_phandles - Adjust the phandles of a whole overlay
164 * @fdto: Device tree overlay blob
165 * @delta: Offset to shift the phandles of
167 * overlay_adjust_local_phandles() adds a constant to all the
168 * phandles of an overlay. This is mainly use as part of the overlay
169 * application process, when we want to update all the overlay
170 * phandles to not conflict with the overlays of the base device tree.
174 * Negative error code on failure
176 static int overlay_adjust_local_phandles(void *fdto, uint32_t delta)
179 * Start adjusting the phandles from the overlay root
181 return overlay_adjust_node_phandles(fdto, 0, delta);
185 * overlay_update_local_node_references - Adjust the overlay references
186 * @fdto: Device tree overlay blob
187 * @tree_node: Node offset of the node to operate on
188 * @fixup_node: Node offset of the matching local fixups node
189 * @delta: Offset to shift the phandles of
191 * overlay_update_local_nodes_references() update the phandles
192 * pointing to a node within the device tree overlay by adding a
195 * This is mainly used as part of a device tree application process,
196 * where you want the device tree overlays phandles to not conflict
197 * with the ones from the base device tree before merging them.
201 * Negative error code on failure
203 static int overlay_update_local_node_references(void *fdto,
212 fdt_for_each_property_offset(fixup_prop, fdto, fixup_node) {
213 const uint32_t *fixup_val;
214 const char *tree_val;
220 fixup_val = fdt_getprop_by_offset(fdto, fixup_prop,
225 if (fixup_len % sizeof(uint32_t))
226 return -FDT_ERR_BADOVERLAY;
228 tree_val = fdt_getprop(fdto, tree_node, name, &tree_len);
230 if (tree_len == -FDT_ERR_NOTFOUND)
231 return -FDT_ERR_BADOVERLAY;
236 for (i = 0; i < (fixup_len / sizeof(uint32_t)); i++) {
237 uint32_t adj_val, poffset;
239 poffset = fdt32_to_cpu(fixup_val[i]);
242 * phandles to fixup can be unaligned.
244 * Use a memcpy for the architectures that do
245 * not support unaligned accesses.
247 memcpy(&adj_val, tree_val + poffset, sizeof(adj_val));
249 adj_val = fdt32_to_cpu(adj_val);
251 adj_val = cpu_to_fdt32(adj_val);
253 ret = fdt_setprop_inplace_namelen_partial(fdto,
260 if (ret == -FDT_ERR_NOSPACE)
261 return -FDT_ERR_BADOVERLAY;
268 fdt_for_each_subnode(fixup_child, fdto, fixup_node) {
269 const char *fixup_child_name = fdt_get_name(fdto, fixup_child,
273 tree_child = fdt_subnode_offset(fdto, tree_node,
275 if (ret == -FDT_ERR_NOTFOUND)
276 return -FDT_ERR_BADOVERLAY;
280 ret = overlay_update_local_node_references(fdto,
292 * overlay_update_local_references - Adjust the overlay references
293 * @fdto: Device tree overlay blob
294 * @delta: Offset to shift the phandles of
296 * overlay_update_local_references() update all the phandles pointing
297 * to a node within the device tree overlay by adding a constant
298 * delta to not conflict with the base overlay.
300 * This is mainly used as part of a device tree application process,
301 * where you want the device tree overlays phandles to not conflict
302 * with the ones from the base device tree before merging them.
306 * Negative error code on failure
308 static int overlay_update_local_references(void *fdto, uint32_t delta)
312 fixups = fdt_path_offset(fdto, "/__local_fixups__");
314 /* There's no local phandles to adjust, bail out */
315 if (fixups == -FDT_ERR_NOTFOUND)
322 * Update our local references from the root of the tree
324 return overlay_update_local_node_references(fdto, 0, fixups,
329 * overlay_fixup_one_phandle - Set an overlay phandle to the base one
330 * @fdt: Base Device Tree blob
331 * @fdto: Device tree overlay blob
332 * @symbols_off: Node offset of the symbols node in the base device tree
333 * @path: Path to a node holding a phandle in the overlay
334 * @path_len: number of path characters to consider
335 * @name: Name of the property holding the phandle reference in the overlay
336 * @name_len: number of name characters to consider
337 * @poffset: Offset within the overlay property where the phandle is stored
338 * @label: Label of the node referenced by the phandle
340 * overlay_fixup_one_phandle() resolves an overlay phandle pointing to
341 * a node in the base device tree.
343 * This is part of the device tree overlay application process, when
344 * you want all the phandles in the overlay to point to the actual
349 * Negative error code on failure
351 static int overlay_fixup_one_phandle(void *fdt, void *fdto,
353 const char *path, uint32_t path_len,
354 const char *name, uint32_t name_len,
355 int poffset, const char *label)
357 const char *symbol_path;
359 int symbol_off, fixup_off;
365 symbol_path = fdt_getprop(fdt, symbols_off, label,
370 symbol_off = fdt_path_offset(fdt, symbol_path);
374 phandle = fdt_get_phandle(fdt, symbol_off);
376 return -FDT_ERR_NOTFOUND;
378 fixup_off = fdt_path_offset_namelen(fdto, path, path_len);
379 if (fixup_off == -FDT_ERR_NOTFOUND)
380 return -FDT_ERR_BADOVERLAY;
384 phandle = cpu_to_fdt32(phandle);
385 return fdt_setprop_inplace_namelen_partial(fdto, fixup_off,
386 name, name_len, poffset,
387 &phandle, sizeof(phandle));
391 * overlay_fixup_phandle - Set an overlay phandle to the base one
392 * @fdt: Base Device Tree blob
393 * @fdto: Device tree overlay blob
394 * @symbols_off: Node offset of the symbols node in the base device tree
395 * @property: Property offset in the overlay holding the list of fixups
397 * overlay_fixup_phandle() resolves all the overlay phandles pointed
398 * to in a __fixups__ property, and updates them to match the phandles
399 * in use in the base device tree.
401 * This is part of the device tree overlay application process, when
402 * you want all the phandles in the overlay to point to the actual
407 * Negative error code on failure
409 static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off,
416 value = fdt_getprop_by_offset(fdto, property,
419 if (len == -FDT_ERR_NOTFOUND)
420 return -FDT_ERR_INTERNAL;
426 const char *path, *name, *fixup_end;
427 const char *fixup_str = value;
428 uint32_t path_len, name_len;
433 fixup_end = memchr(value, '\0', len);
435 return -FDT_ERR_BADOVERLAY;
436 fixup_len = fixup_end - fixup_str;
438 len -= fixup_len + 1;
439 value += fixup_len + 1;
442 sep = memchr(fixup_str, ':', fixup_len);
443 if (!sep || *sep != ':')
444 return -FDT_ERR_BADOVERLAY;
446 path_len = sep - path;
447 if (path_len == (fixup_len - 1))
448 return -FDT_ERR_BADOVERLAY;
450 fixup_len -= path_len + 1;
452 sep = memchr(name, ':', fixup_len);
453 if (!sep || *sep != ':')
454 return -FDT_ERR_BADOVERLAY;
456 name_len = sep - name;
458 return -FDT_ERR_BADOVERLAY;
460 poffset = strtoul(sep + 1, &endptr, 10);
461 if ((*endptr != '\0') || (endptr <= (sep + 1)))
462 return -FDT_ERR_BADOVERLAY;
464 ret = overlay_fixup_one_phandle(fdt, fdto, symbols_off,
465 path, path_len, name, name_len,
475 * overlay_fixup_phandles - Resolve the overlay phandles to the base
477 * @fdt: Base Device Tree blob
478 * @fdto: Device tree overlay blob
480 * overlay_fixup_phandles() resolves all the overlay phandles pointing
481 * to nodes in the base device tree.
483 * This is one of the steps of the device tree overlay application
484 * process, when you want all the phandles in the overlay to point to
485 * the actual base dt nodes.
489 * Negative error code on failure
491 static int overlay_fixup_phandles(void *fdt, void *fdto)
493 int fixups_off, symbols_off;
496 /* We can have overlays without any fixups */
497 fixups_off = fdt_path_offset(fdto, "/__fixups__");
498 if (fixups_off == -FDT_ERR_NOTFOUND)
499 return 0; /* nothing to do */
503 /* And base DTs without symbols */
504 symbols_off = fdt_path_offset(fdt, "/__symbols__");
505 if ((symbols_off < 0 && (symbols_off != -FDT_ERR_NOTFOUND)))
508 fdt_for_each_property_offset(property, fdto, fixups_off) {
511 ret = overlay_fixup_phandle(fdt, fdto, symbols_off, property);
520 * overlay_apply_node - Merges a node into the base device tree
521 * @fdt: Base Device Tree blob
522 * @target: Node offset in the base device tree to apply the fragment to
523 * @fdto: Device tree overlay blob
524 * @node: Node offset in the overlay holding the changes to merge
526 * overlay_apply_node() merges a node into a target base device tree
529 * This is part of the final step in the device tree overlay
530 * application process, when all the phandles have been adjusted and
531 * resolved and you just have to merge overlay into the base device
536 * Negative error code on failure
538 static int overlay_apply_node(void *fdt, int target,
539 void *fdto, int node)
544 fdt_for_each_property_offset(property, fdto, node) {
550 prop = fdt_getprop_by_offset(fdto, property, &name,
552 if (prop_len == -FDT_ERR_NOTFOUND)
553 return -FDT_ERR_INTERNAL;
557 ret = fdt_setprop(fdt, target, name, prop, prop_len);
562 fdt_for_each_subnode(subnode, fdto, node) {
563 const char *name = fdt_get_name(fdto, subnode, NULL);
567 nnode = fdt_add_subnode(fdt, target, name);
568 if (nnode == -FDT_ERR_EXISTS) {
569 nnode = fdt_subnode_offset(fdt, target, name);
570 if (nnode == -FDT_ERR_NOTFOUND)
571 return -FDT_ERR_INTERNAL;
577 ret = overlay_apply_node(fdt, nnode, fdto, subnode);
586 * overlay_merge - Merge an overlay into its base device tree
587 * @fdt: Base Device Tree blob
588 * @fdto: Device tree overlay blob
590 * overlay_merge() merges an overlay into its base device tree.
592 * This is the final step in the device tree overlay application
593 * process, when all the phandles have been adjusted and resolved and
594 * you just have to merge overlay into the base device tree.
598 * Negative error code on failure
600 static int overlay_merge(void *fdt, void *fdto)
604 fdt_for_each_subnode(fragment, fdto, 0) {
610 * Each fragments will have an __overlay__ node. If
611 * they don't, it's not supposed to be merged
613 overlay = fdt_subnode_offset(fdto, fragment, "__overlay__");
614 if (overlay == -FDT_ERR_NOTFOUND)
620 target = overlay_get_target(fdt, fdto, fragment);
624 ret = overlay_apply_node(fdt, target, fdto, overlay);
632 int fdt_overlay_apply(void *fdt, void *fdto)
634 uint32_t delta = fdt_get_max_phandle(fdt);
637 FDT_CHECK_HEADER(fdt);
638 FDT_CHECK_HEADER(fdto);
640 ret = overlay_adjust_local_phandles(fdto, delta);
644 ret = overlay_update_local_references(fdto, delta);
648 ret = overlay_fixup_phandles(fdt, fdto);
652 ret = overlay_merge(fdt, fdto);
657 * The overlay has been damaged, erase its magic.
659 fdt_set_magic(fdto, ~0);
665 * The overlay might have been damaged, erase its magic.
667 fdt_set_magic(fdto, ~0);
670 * The base device tree might have been damaged, erase its
673 fdt_set_magic(fdt, ~0);