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Masahiro Yamada25ad2022018-01-21 19:19:16 +09001#ifndef UBOOT_LIBFDT_H
2#define UBOOT_LIBFDT_H
3/*
4 * SPDX-License-Identifier: GPL-2.0+ BSD-2-Clause
5 */
6
Masahiro Yamada144fbea2018-01-21 19:19:17 +09007#ifdef USE_HOSTCC
8#include "../scripts/dtc/libfdt/libfdt.h"
9#else
10#include <linux/libfdt.h>
11#endif
Masahiro Yamada25ad2022018-01-21 19:19:16 +090012
Masahiro Yamada144fbea2018-01-21 19:19:17 +090013/* U-Boot local hacks */
14
15#ifndef SWIG /* Not available in Python */
16struct fdt_region {
17 int offset;
18 int size;
19};
20
21/*
22 * Flags for fdt_find_regions()
23 *
24 * Add a region for the string table (always the last region)
25 */
26#define FDT_REG_ADD_STRING_TAB (1 << 0)
27
28/*
29 * Add all supernodes of a matching node/property, useful for creating a
30 * valid subset tree
31 */
32#define FDT_REG_SUPERNODES (1 << 1)
33
34/* Add the FDT_BEGIN_NODE tags of subnodes, including their names */
35#define FDT_REG_DIRECT_SUBNODES (1 << 2)
36
37/* Add all subnodes of a matching node */
38#define FDT_REG_ALL_SUBNODES (1 << 3)
39
40/* Add a region for the mem_rsvmap table (always the first region) */
41#define FDT_REG_ADD_MEM_RSVMAP (1 << 4)
42
43/* Indicates what an fdt part is (node, property, value) */
44#define FDT_IS_NODE (1 << 0)
45#define FDT_IS_PROP (1 << 1)
46#define FDT_IS_VALUE (1 << 2) /* not supported */
47#define FDT_IS_COMPAT (1 << 3) /* used internally */
48#define FDT_NODE_HAS_PROP (1 << 4) /* node contains prop */
49
50#define FDT_ANY_GLOBAL (FDT_IS_NODE | FDT_IS_PROP | FDT_IS_VALUE | \
51 FDT_IS_COMPAT)
52#define FDT_IS_ANY 0x1f /* all the above */
53
54/* We set a reasonable limit on the number of nested nodes */
55#define FDT_MAX_DEPTH 32
56
57/* Decribes what we want to include from the current tag */
58enum want_t {
59 WANT_NOTHING,
60 WANT_NODES_ONLY, /* No properties */
61 WANT_NODES_AND_PROPS, /* Everything for one level */
62 WANT_ALL_NODES_AND_PROPS /* Everything for all levels */
63};
64
65/* Keeps track of the state at parent nodes */
66struct fdt_subnode_stack {
67 int offset; /* Offset of node */
68 enum want_t want; /* The 'want' value here */
69 int included; /* 1 if we included this node, 0 if not */
70};
71
72struct fdt_region_ptrs {
73 int depth; /* Current tree depth */
74 int done; /* What we have completed scanning */
75 enum want_t want; /* What we are currently including */
76 char *end; /* Pointer to end of full node path */
77 int nextoffset; /* Next node offset to check */
78};
79
80/* The state of our finding algortihm */
81struct fdt_region_state {
82 struct fdt_subnode_stack stack[FDT_MAX_DEPTH]; /* node stack */
83 struct fdt_region *region; /* Contains list of regions found */
84 int count; /* Numnber of regions found */
85 const void *fdt; /* FDT blob */
86 int max_regions; /* Maximum regions to find */
87 int can_merge; /* 1 if we can merge with previous region */
88 int start; /* Start position of current region */
89 struct fdt_region_ptrs ptrs; /* Pointers for what we are up to */
90};
91
92/**
93 * fdt_find_regions() - find regions in device tree
94 *
95 * Given a list of nodes to include and properties to exclude, find
96 * the regions of the device tree which describe those included parts.
97 *
98 * The intent is to get a list of regions which will be invariant provided
99 * those parts are invariant. For example, if you request a list of regions
100 * for all nodes but exclude the property "data", then you will get the
101 * same region contents regardless of any change to "data" properties.
102 *
103 * This function can be used to produce a byte-stream to send to a hashing
104 * function to verify that critical parts of the FDT have not changed.
105 *
106 * Nodes which are given in 'inc' are included in the region list, as
107 * are the names of the immediate subnodes nodes (but not the properties
108 * or subnodes of those subnodes).
109 *
110 * For eaxample "/" means to include the root node, all root properties
111 * and the FDT_BEGIN_NODE and FDT_END_NODE of all subnodes of /. The latter
112 * ensures that we capture the names of the subnodes. In a hashing situation
113 * it prevents the root node from changing at all Any change to non-excluded
114 * properties, names of subnodes or number of subnodes would be detected.
115 *
116 * When used with FITs this provides the ability to hash and sign parts of
117 * the FIT based on different configurations in the FIT. Then it is
118 * impossible to change anything about that configuration (include images
119 * attached to the configuration), but it may be possible to add new
120 * configurations, new images or new signatures within the existing
121 * framework.
122 *
123 * Adding new properties to a device tree may result in the string table
124 * being extended (if the new property names are different from those
125 * already added). This function can optionally include a region for
126 * the string table so that this can be part of the hash too.
127 *
128 * The device tree header is not included in the list.
129 *
130 * @fdt: Device tree to check
131 * @inc: List of node paths to included
132 * @inc_count: Number of node paths in list
133 * @exc_prop: List of properties names to exclude
134 * @exc_prop_count: Number of properties in exclude list
135 * @region: Returns list of regions
136 * @max_region: Maximum length of region list
137 * @path: Pointer to a temporary string for the function to use for
138 * building path names
139 * @path_len: Length of path, must be large enough to hold the longest
140 * path in the tree
141 * @add_string_tab: 1 to add a region for the string table
142 * @return number of regions in list. If this is >max_regions then the
143 * region array was exhausted. You should increase max_regions and try
144 * the call again.
145 */
146int fdt_find_regions(const void *fdt, char * const inc[], int inc_count,
147 char * const exc_prop[], int exc_prop_count,
148 struct fdt_region region[], int max_regions,
149 char *path, int path_len, int add_string_tab);
150
151/**
152 * fdt_first_region() - find regions in device tree
153 *
154 * Given a nodes and properties to include and properties to exclude, find
155 * the regions of the device tree which describe those included parts.
156 *
157 * The use for this function is twofold. Firstly it provides a convenient
158 * way of performing a structure-aware grep of the tree. For example it is
159 * possible to grep for a node and get all the properties associated with
160 * that node. Trees can be subsetted easily, by specifying the nodes that
161 * are required, and then writing out the regions returned by this function.
162 * This is useful for small resource-constrained systems, such as boot
163 * loaders, which want to use an FDT but do not need to know about all of
164 * it.
165 *
166 * Secondly it makes it easy to hash parts of the tree and detect changes.
167 * The intent is to get a list of regions which will be invariant provided
168 * those parts are invariant. For example, if you request a list of regions
169 * for all nodes but exclude the property "data", then you will get the
170 * same region contents regardless of any change to "data" properties.
171 *
172 * This function can be used to produce a byte-stream to send to a hashing
173 * function to verify that critical parts of the FDT have not changed.
174 * Note that semantically null changes in order could still cause false
175 * hash misses. Such reordering might happen if the tree is regenerated
176 * from source, and nodes are reordered (the bytes-stream will be emitted
177 * in a different order and many hash functions will detect this). However
178 * if an existing tree is modified using libfdt functions, such as
179 * fdt_add_subnode() and fdt_setprop(), then this problem is avoided.
180 *
181 * The nodes/properties to include/exclude are defined by a function
182 * provided by the caller. This function is called for each node and
183 * property, and must return:
184 *
185 * 0 - to exclude this part
186 * 1 - to include this part
187 * -1 - for FDT_IS_PROP only: no information is available, so include
188 * if its containing node is included
189 *
190 * The last case is only used to deal with properties. Often a property is
191 * included if its containing node is included - this is the case where
192 * -1 is returned.. However if the property is specifically required to be
193 * included/excluded, then 0 or 1 can be returned. Note that including a
194 * property when the FDT_REG_SUPERNODES flag is given will force its
195 * containing node to be included since it is not valid to have a property
196 * that is not in a node.
197 *
198 * Using the information provided, the inclusion of a node can be controlled
199 * either by a node name or its compatible string, or any other property
200 * that the function can determine.
201 *
202 * As an example, including node "/" means to include the root node and all
203 * root properties. A flag provides a way of also including supernodes (of
204 * which there is none for the root node), and another flag includes
205 * immediate subnodes, so in this case we would get the FDT_BEGIN_NODE and
206 * FDT_END_NODE of all subnodes of /.
207 *
208 * The subnode feature helps in a hashing situation since it prevents the
209 * root node from changing at all. Any change to non-excluded properties,
210 * names of subnodes or number of subnodes would be detected.
211 *
212 * When used with FITs this provides the ability to hash and sign parts of
213 * the FIT based on different configurations in the FIT. Then it is
214 * impossible to change anything about that configuration (include images
215 * attached to the configuration), but it may be possible to add new
216 * configurations, new images or new signatures within the existing
217 * framework.
218 *
219 * Adding new properties to a device tree may result in the string table
220 * being extended (if the new property names are different from those
221 * already added). This function can optionally include a region for
222 * the string table so that this can be part of the hash too. This is always
223 * the last region.
224 *
225 * The FDT also has a mem_rsvmap table which can also be included, and is
226 * always the first region if so.
227 *
228 * The device tree header is not included in the region list. Since the
229 * contents of the FDT are changing (shrinking, often), the caller will need
230 * to regenerate the header anyway.
231 *
232 * @fdt: Device tree to check
233 * @h_include: Function to call to determine whether to include a part or
234 * not:
235 *
236 * @priv: Private pointer as passed to fdt_find_regions()
237 * @fdt: Pointer to FDT blob
238 * @offset: Offset of this node / property
239 * @type: Type of this part, FDT_IS_...
240 * @data: Pointer to data (node name, property name, compatible
241 * string, value (not yet supported)
242 * @size: Size of data, or 0 if none
243 * @return 0 to exclude, 1 to include, -1 if no information is
244 * available
245 * @priv: Private pointer passed to h_include
246 * @region: Returns list of regions, sorted by offset
247 * @max_regions: Maximum length of region list
248 * @path: Pointer to a temporary string for the function to use for
249 * building path names
250 * @path_len: Length of path, must be large enough to hold the longest
251 * path in the tree
252 * @flags: Various flags that control the region algortihm, see
253 * FDT_REG_...
254 * @return number of regions in list. If this is >max_regions then the
255 * region array was exhausted. You should increase max_regions and try
256 * the call again. Only the first max_regions elements are available in the
257 * array.
258 *
259 * On error a -ve value is return, which can be:
260 *
261 * -FDT_ERR_BADSTRUCTURE (too deep or more END tags than BEGIN tags
262 * -FDT_ERR_BADLAYOUT
263 * -FDT_ERR_NOSPACE (path area is too small)
264 */
265int fdt_first_region(const void *fdt,
266 int (*h_include)(void *priv, const void *fdt, int offset,
267 int type, const char *data, int size),
268 void *priv, struct fdt_region *region,
269 char *path, int path_len, int flags,
270 struct fdt_region_state *info);
271
272/** fdt_next_region() - find next region
273 *
274 * See fdt_first_region() for full description. This function finds the
275 * next region according to the provided parameters, which must be the same
276 * as passed to fdt_first_region().
277 *
278 * This function can additionally return -FDT_ERR_NOTFOUND when there are no
279 * more regions
280 */
281int fdt_next_region(const void *fdt,
282 int (*h_include)(void *priv, const void *fdt, int offset,
283 int type, const char *data, int size),
284 void *priv, struct fdt_region *region,
285 char *path, int path_len, int flags,
286 struct fdt_region_state *info);
287
288/**
289 * fdt_add_alias_regions() - find aliases that point to existing regions
290 *
291 * Once a device tree grep is complete some of the nodes will be present
292 * and some will have been dropped. This function checks all the alias nodes
293 * to figure out which points point to nodes which are still present. These
294 * aliases need to be kept, along with the nodes they reference.
295 *
296 * Given a list of regions function finds the aliases that still apply and
297 * adds more regions to the list for these. This function is called after
298 * fdt_next_region() has finished returning regions and requires the same
299 * state.
300 *
301 * @fdt: Device tree file to reference
302 * @region: List of regions that will be kept
303 * @count: Number of regions
304 * @max_regions: Number of entries that can fit in @region
305 * @info: Region state as returned from fdt_next_region()
306 * @return new number of regions in @region (i.e. count + the number added)
307 * or -FDT_ERR_NOSPACE if there was not enough space.
308 */
309int fdt_add_alias_regions(const void *fdt, struct fdt_region *region, int count,
310 int max_regions, struct fdt_region_state *info);
311#endif /* SWIG */
312
313extern struct fdt_header *working_fdt; /* Pointer to the working fdt */
Masahiro Yamada25ad2022018-01-21 19:19:16 +0900314
315/* adding a ramdisk needs 0x44 bytes in version 2008.10 */
316#define FDT_RAMDISK_OVERHEAD 0x80
317
318#endif /* UBOOT_LIBFDT_H */