[J-u-boot.git] / include / fdt_region.h

/* SPDX-License-Identifier: GPL-2.0 */

#ifndef _FDT_REGION_H
#define _FDT_REGION_H

#ifndef SWIG /* Not available in Python */
struct fdt_region {
	int offset;
	int size;
};

/*
 * Flags for fdt_find_regions()
 *
 * Add a region for the string table (always the last region)
 */
#define FDT_REG_ADD_STRING_TAB		(1 << 0)

/*
 * Add all supernodes of a matching node/property, useful for creating a
 * valid subset tree
 */
#define FDT_REG_SUPERNODES		(1 << 1)

/* Add the FDT_BEGIN_NODE tags of subnodes, including their names */
#define FDT_REG_DIRECT_SUBNODES	(1 << 2)

/* Add all subnodes of a matching node */
#define FDT_REG_ALL_SUBNODES		(1 << 3)

/* Add a region for the mem_rsvmap table (always the first region) */
#define FDT_REG_ADD_MEM_RSVMAP		(1 << 4)

/* Indicates what an fdt part is (node, property, value) */
#define FDT_IS_NODE			(1 << 0)
#define FDT_IS_PROP			(1 << 1)
#define FDT_IS_VALUE			(1 << 2)	/* not supported */
#define FDT_IS_COMPAT			(1 << 3)	/* used internally */
#define FDT_NODE_HAS_PROP		(1 << 4)	/* node contains prop */

#define FDT_ANY_GLOBAL		(FDT_IS_NODE | FDT_IS_PROP | FDT_IS_VALUE | \
					FDT_IS_COMPAT)
#define FDT_IS_ANY			0x1f		/* all the above */

/* We set a reasonable limit on the number of nested nodes */
#define FDT_MAX_DEPTH			32

/* Decribes what we want to include from the current tag */
enum want_t {
	WANT_NOTHING,
	WANT_NODES_ONLY,		/* No properties */
	WANT_NODES_AND_PROPS,		/* Everything for one level */
	WANT_ALL_NODES_AND_PROPS	/* Everything for all levels */
};

/* Keeps track of the state at parent nodes */
struct fdt_subnode_stack {
	int offset;		/* Offset of node */
	enum want_t want;	/* The 'want' value here */
	int included;		/* 1 if we included this node, 0 if not */
};

struct fdt_region_ptrs {
	int depth;			/* Current tree depth */
	int done;			/* What we have completed scanning */
	enum want_t want;		/* What we are currently including */
	char *end;			/* Pointer to end of full node path */
	int nextoffset;			/* Next node offset to check */
};

/* The state of our finding algortihm */
struct fdt_region_state {
	struct fdt_subnode_stack stack[FDT_MAX_DEPTH];	/* node stack */
	struct fdt_region *region;	/* Contains list of regions found */
	int count;			/* Numnber of regions found */
	const void *fdt;		/* FDT blob */
	int max_regions;		/* Maximum regions to find */
	int can_merge;		/* 1 if we can merge with previous region */
	int start;			/* Start position of current region */
	bool have_node;			/* True if any node is included */
	struct fdt_region_ptrs ptrs;	/* Pointers for what we are up to */
};

/**
 * fdt_find_regions() - find regions in device tree
 *
 * Given a list of nodes to include and properties to exclude, find
 * the regions of the device tree which describe those included parts.
 *
 * The intent is to get a list of regions which will be invariant provided
 * those parts are invariant. For example, if you request a list of regions
 * for all nodes but exclude the property "data", then you will get the
 * same region contents regardless of any change to "data" properties.
 *
 * This function can be used to produce a byte-stream to send to a hashing
 * function to verify that critical parts of the FDT have not changed.
 *
 * Nodes which are given in 'inc' are included in the region list, as
 * are the names of the immediate subnodes nodes (but not the properties
 * or subnodes of those subnodes).
 *
 * For eaxample "/" means to include the root node, all root properties
 * and the FDT_BEGIN_NODE and FDT_END_NODE of all subnodes of /. The latter
 * ensures that we capture the names of the subnodes. In a hashing situation
 * it prevents the root node from changing at all Any change to non-excluded
 * properties, names of subnodes or number of subnodes would be detected.
 *
 * When used with FITs this provides the ability to hash and sign parts of
 * the FIT based on different configurations in the FIT. Then it is
 * impossible to change anything about that configuration (include images
 * attached to the configuration), but it may be possible to add new
 * configurations, new images or new signatures within the existing
 * framework.
 *
 * Adding new properties to a device tree may result in the string table
 * being extended (if the new property names are different from those
 * already added). This function can optionally include a region for
 * the string table so that this can be part of the hash too.
 *
 * The device tree header is not included in the list.
 *
 * @fdt:	Device tree to check
 * @inc:	List of node paths to included
 * @inc_count:	Number of node paths in list
 * @exc_prop:	List of properties names to exclude
 * @exc_prop_count:	Number of properties in exclude list
 * @region:	Returns list of regions
 * @max_region:	Maximum length of region list
 * @path:	Pointer to a temporary string for the function to use for
 *		building path names
 * @path_len:	Length of path, must be large enough to hold the longest
 *		path in the tree
 * @add_string_tab:	1 to add a region for the string table
 * @return number of regions in list. If this is >max_regions then the
 * region array was exhausted. You should increase max_regions and try
 * the call again.
 */
int fdt_find_regions(const void *fdt, char * const inc[], int inc_count,
		     char * const exc_prop[], int exc_prop_count,
		     struct fdt_region region[], int max_regions,
		     char *path, int path_len, int add_string_tab);

/**
 * fdt_first_region() - find regions in device tree
 *
 * Given a nodes and properties to include and properties to exclude, find
 * the regions of the device tree which describe those included parts.
 *
 * The use for this function is twofold. Firstly it provides a convenient
 * way of performing a structure-aware grep of the tree. For example it is
 * possible to grep for a node and get all the properties associated with
 * that node. Trees can be subsetted easily, by specifying the nodes that
 * are required, and then writing out the regions returned by this function.
 * This is useful for small resource-constrained systems, such as boot
 * loaders, which want to use an FDT but do not need to know about all of
 * it.
 *
 * Secondly it makes it easy to hash parts of the tree and detect changes.
 * The intent is to get a list of regions which will be invariant provided
 * those parts are invariant. For example, if you request a list of regions
 * for all nodes but exclude the property "data", then you will get the
 * same region contents regardless of any change to "data" properties.
 *
 * This function can be used to produce a byte-stream to send to a hashing
 * function to verify that critical parts of the FDT have not changed.
 * Note that semantically null changes in order could still cause false
 * hash misses. Such reordering might happen if the tree is regenerated
 * from source, and nodes are reordered (the bytes-stream will be emitted
 * in a different order and many hash functions will detect this). However
 * if an existing tree is modified using libfdt functions, such as
 * fdt_add_subnode() and fdt_setprop(), then this problem is avoided.
 *
 * The nodes/properties to include/exclude are defined by a function
 * provided by the caller. This function is called for each node and
 * property, and must return:
 *
 *    0 - to exclude this part
 *    1 - to include this part
 *   -1 - for FDT_IS_PROP only: no information is available, so include
 *		if its containing node is included
 *
 * The last case is only used to deal with properties. Often a property is
 * included if its containing node is included - this is the case where
 * -1 is returned.. However if the property is specifically required to be
 * included/excluded, then 0 or 1 can be returned. Note that including a
 * property when the FDT_REG_SUPERNODES flag is given will force its
 * containing node to be included since it is not valid to have a property
 * that is not in a node.
 *
 * Using the information provided, the inclusion of a node can be controlled
 * either by a node name or its compatible string, or any other property
 * that the function can determine.
 *
 * As an example, including node "/" means to include the root node and all
 * root properties. A flag provides a way of also including supernodes (of
 * which there is none for the root node), and another flag includes
 * immediate subnodes, so in this case we would get the FDT_BEGIN_NODE and
 * FDT_END_NODE of all subnodes of /.
 *
 * The subnode feature helps in a hashing situation since it prevents the
 * root node from changing at all. Any change to non-excluded properties,
 * names of subnodes or number of subnodes would be detected.
 *
 * When used with FITs this provides the ability to hash and sign parts of
 * the FIT based on different configurations in the FIT. Then it is
 * impossible to change anything about that configuration (include images
 * attached to the configuration), but it may be possible to add new
 * configurations, new images or new signatures within the existing
 * framework.
 *
 * Adding new properties to a device tree may result in the string table
 * being extended (if the new property names are different from those
 * already added). This function can optionally include a region for
 * the string table so that this can be part of the hash too. This is always
 * the last region.
 *
 * The FDT also has a mem_rsvmap table which can also be included, and is
 * always the first region if so.
 *
 * The device tree header is not included in the region list. Since the
 * contents of the FDT are changing (shrinking, often), the caller will need
 * to regenerate the header anyway.
 *
 * @fdt:	Device tree to check
 * @h_include:	Function to call to determine whether to include a part or
 *		not:
 *
 *		@priv: Private pointer as passed to fdt_find_regions()
 *		@fdt: Pointer to FDT blob
 *		@offset: Offset of this node / property
 *		@type: Type of this part, FDT_IS_...
 *		@data: Pointer to data (node name, property name, compatible
 *			string, value (not yet supported)
 *		@size: Size of data, or 0 if none
 *		@return 0 to exclude, 1 to include, -1 if no information is
 *		available
 * @priv:	Private pointer passed to h_include
 * @region:	Returns list of regions, sorted by offset
 * @max_regions: Maximum length of region list
 * @path:	Pointer to a temporary string for the function to use for
 *		building path names
 * @path_len:	Length of path, must be large enough to hold the longest
 *		path in the tree
 * @flags:	Various flags that control the region algortihm, see
 *		FDT_REG_...
 * @return number of regions in list. If this is >max_regions then the
 * region array was exhausted. You should increase max_regions and try
 * the call again. Only the first max_regions elements are available in the
 * array.
 *
 * On error a -ve value is return, which can be:
 *
 *	-FDT_ERR_BADSTRUCTURE (too deep or more END tags than BEGIN tags
 *	-FDT_ERR_BADLAYOUT
 *	-FDT_ERR_NOSPACE (path area is too small)
 */
int fdt_first_region(const void *fdt,
		     int (*h_include)(void *priv, const void *fdt, int offset,
				      int type, const char *data, int size),
		     void *priv, struct fdt_region *region,
		     char *path, int path_len, int flags,
		     struct fdt_region_state *info);

/** fdt_next_region() - find next region
 *
 * See fdt_first_region() for full description. This function finds the
 * next region according to the provided parameters, which must be the same
 * as passed to fdt_first_region().
 *
 * This function can additionally return -FDT_ERR_NOTFOUND when there are no
 * more regions
 */
int fdt_next_region(const void *fdt,
		    int (*h_include)(void *priv, const void *fdt, int offset,
				     int type, const char *data, int size),
		    void *priv, struct fdt_region *region,
		    char *path, int path_len, int flags,
		    struct fdt_region_state *info);

/**
 * fdt_add_alias_regions() - find aliases that point to existing regions
 *
 * Once a device tree grep is complete some of the nodes will be present
 * and some will have been dropped. This function checks all the alias nodes
 * to figure out which points point to nodes which are still present. These
 * aliases need to be kept, along with the nodes they reference.
 *
 * Given a list of regions function finds the aliases that still apply and
 * adds more regions to the list for these. This function is called after
 * fdt_next_region() has finished returning regions and requires the same
 * state.
 *
 * @fdt:	Device tree file to reference
 * @region:	List of regions that will be kept
 * @count:	Number of regions
 * @max_regions: Number of entries that can fit in @region
 * @info:	Region state as returned from fdt_next_region()
 * @return new number of regions in @region (i.e. count + the number added)
 * or -FDT_ERR_NOSPACE if there was not enough space.
 */
int fdt_add_alias_regions(const void *fdt, struct fdt_region *region, int count,
			  int max_regions, struct fdt_region_state *info);
#endif /* SWIG */

#endif /* _FDT_REGION_H */
Commit	Line	Data
64045a6a MY	1	/* SPDX-License-Identifier: GPL-2.0 */
	2
	3	#ifndef _FDT_REGION_H
	4	#define _FDT_REGION_H
	5
	6	#ifndef SWIG /* Not available in Python */
	7	struct fdt_region {
	8	int offset;
	9	int size;
	10	};
	11
	12	/*
	13	* Flags for fdt_find_regions()
	14	*
	15	* Add a region for the string table (always the last region)
	16	*/
	17	#define FDT_REG_ADD_STRING_TAB (1 << 0)
	18
	19	/*
	20	* Add all supernodes of a matching node/property, useful for creating a
	21	* valid subset tree
	22	*/
	23	#define FDT_REG_SUPERNODES (1 << 1)
	24
	25	/* Add the FDT_BEGIN_NODE tags of subnodes, including their names */
	26	#define FDT_REG_DIRECT_SUBNODES (1 << 2)
	27
	28	/* Add all subnodes of a matching node */
	29	#define FDT_REG_ALL_SUBNODES (1 << 3)
	30
	31	/* Add a region for the mem_rsvmap table (always the first region) */
	32	#define FDT_REG_ADD_MEM_RSVMAP (1 << 4)
	33
	34	/* Indicates what an fdt part is (node, property, value) */
	35	#define FDT_IS_NODE (1 << 0)
	36	#define FDT_IS_PROP (1 << 1)
	37	#define FDT_IS_VALUE (1 << 2) /* not supported */
	38	#define FDT_IS_COMPAT (1 << 3) /* used internally */
	39	#define FDT_NODE_HAS_PROP (1 << 4) /* node contains prop */
	40
	41	#define FDT_ANY_GLOBAL (FDT_IS_NODE \| FDT_IS_PROP \| FDT_IS_VALUE \| \
	42	FDT_IS_COMPAT)
	43	#define FDT_IS_ANY 0x1f /* all the above */
	44
	45	/* We set a reasonable limit on the number of nested nodes */
	46	#define FDT_MAX_DEPTH 32
	47
	48	/* Decribes what we want to include from the current tag */
	49	enum want_t {
	50	WANT_NOTHING,
	51	WANT_NODES_ONLY, /* No properties */
	52	WANT_NODES_AND_PROPS, /* Everything for one level */
	53	WANT_ALL_NODES_AND_PROPS /* Everything for all levels */
	54	};
	55
	56	/* Keeps track of the state at parent nodes */
	57	struct fdt_subnode_stack {
	58	int offset; /* Offset of node */
	59	enum want_t want; /* The 'want' value here */
	60	int included; /* 1 if we included this node, 0 if not */
	61	};
	62
	63	struct fdt_region_ptrs {
	64	int depth; /* Current tree depth */
65	int done; /* What we have completed scanning */
66	enum want_t want; /* What we are currently including */
67	char end; / Pointer to end of full node path */
68	int nextoffset; /* Next node offset to check */
69	};
70
71	/* The state of our finding algortihm */
72	struct fdt_region_state {
73	struct fdt_subnode_stack stack[FDT_MAX_DEPTH]; /* node stack */
74	struct fdt_region region; / Contains list of regions found */
75	int count; /* Numnber of regions found */
76	const void fdt; / FDT blob */
77	int max_regions; /* Maximum regions to find */
78	int can_merge; /* 1 if we can merge with previous region */
79	int start; /* Start position of current region */
121cfe5a	80	bool have_node; /* True if any node is included */
64045a6a MY	81	struct fdt_region_ptrs ptrs; /* Pointers for what we are up to */
	82	};
	83
	84	/**
	85	* fdt_find_regions() - find regions in device tree
	86	*
	87	* Given a list of nodes to include and properties to exclude, find
	88	* the regions of the device tree which describe those included parts.
	89	*
	90	* The intent is to get a list of regions which will be invariant provided
	91	* those parts are invariant. For example, if you request a list of regions
	92	* for all nodes but exclude the property "data", then you will get the
	93	* same region contents regardless of any change to "data" properties.
	94	*
	95	* This function can be used to produce a byte-stream to send to a hashing
	96	* function to verify that critical parts of the FDT have not changed.
	97	*
	98	* Nodes which are given in 'inc' are included in the region list, as
	99	* are the names of the immediate subnodes nodes (but not the properties
	100	* or subnodes of those subnodes).
	101	*
	102	* For eaxample "/" means to include the root node, all root properties
	103	* and the FDT_BEGIN_NODE and FDT_END_NODE of all subnodes of /. The latter
	104	* ensures that we capture the names of the subnodes. In a hashing situation
	105	* it prevents the root node from changing at all Any change to non-excluded
	106	* properties, names of subnodes or number of subnodes would be detected.
	107	*
	108	* When used with FITs this provides the ability to hash and sign parts of
	109	* the FIT based on different configurations in the FIT. Then it is
	110	* impossible to change anything about that configuration (include images
	111	* attached to the configuration), but it may be possible to add new
	112	* configurations, new images or new signatures within the existing
	113	* framework.
	114	*
	115	* Adding new properties to a device tree may result in the string table
	116	* being extended (if the new property names are different from those
	117	* already added). This function can optionally include a region for
	118	* the string table so that this can be part of the hash too.
	119	*
	120	* The device tree header is not included in the list.
	121	*
	122	* @fdt: Device tree to check
	123	* @inc: List of node paths to included
	124	* @inc_count: Number of node paths in list
	125	* @exc_prop: List of properties names to exclude
	126	* @exc_prop_count: Number of properties in exclude list
	127	* @region: Returns list of regions
	128	* @max_region: Maximum length of region list
	129	* @path: Pointer to a temporary string for the function to use for
	130	* building path names
	131	* @path_len: Length of path, must be large enough to hold the longest
	132	* path in the tree
	133	* @add_string_tab: 1 to add a region for the string table
	134	* @return number of regions in list. If this is >max_regions then the
	135	* region array was exhausted. You should increase max_regions and try
	136	* the call again.
	137	*/
	138	int fdt_find_regions(const void fdt, char const inc[], int inc_count,
	139	char * const exc_prop[], int exc_prop_count,
	140	struct fdt_region region[], int max_regions,
	141	char *path, int path_len, int add_string_tab);
	142
	143	/**
	144	* fdt_first_region() - find regions in device tree
145	*
146	* Given a nodes and properties to include and properties to exclude, find
147	* the regions of the device tree which describe those included parts.
148	*
149	* The use for this function is twofold. Firstly it provides a convenient
150	* way of performing a structure-aware grep of the tree. For example it is
151	* possible to grep for a node and get all the properties associated with
152	* that node. Trees can be subsetted easily, by specifying the nodes that
153	* are required, and then writing out the regions returned by this function.
154	* This is useful for small resource-constrained systems, such as boot
155	* loaders, which want to use an FDT but do not need to know about all of
156	* it.
157	*
158	* Secondly it makes it easy to hash parts of the tree and detect changes.
159	* The intent is to get a list of regions which will be invariant provided
160	* those parts are invariant. For example, if you request a list of regions
161	* for all nodes but exclude the property "data", then you will get the
162	* same region contents regardless of any change to "data" properties.
163	*
164	* This function can be used to produce a byte-stream to send to a hashing
165	* function to verify that critical parts of the FDT have not changed.
166	* Note that semantically null changes in order could still cause false
167	* hash misses. Such reordering might happen if the tree is regenerated
168	* from source, and nodes are reordered (the bytes-stream will be emitted
169	* in a different order and many hash functions will detect this). However
170	* if an existing tree is modified using libfdt functions, such as
171	* fdt_add_subnode() and fdt_setprop(), then this problem is avoided.
172	*
173	* The nodes/properties to include/exclude are defined by a function
174	* provided by the caller. This function is called for each node and
175	* property, and must return:
176	*
177	* 0 - to exclude this part
178	* 1 - to include this part
179	* -1 - for FDT_IS_PROP only: no information is available, so include
180	* if its containing node is included
181	*
182	* The last case is only used to deal with properties. Often a property is
183	* included if its containing node is included - this is the case where
184	* -1 is returned.. However if the property is specifically required to be
185	* included/excluded, then 0 or 1 can be returned. Note that including a
186	* property when the FDT_REG_SUPERNODES flag is given will force its
187	* containing node to be included since it is not valid to have a property
188	* that is not in a node.
189	*
190	* Using the information provided, the inclusion of a node can be controlled
191	* either by a node name or its compatible string, or any other property
192	* that the function can determine.
193	*
194	* As an example, including node "/" means to include the root node and all
195	* root properties. A flag provides a way of also including supernodes (of
196	* which there is none for the root node), and another flag includes
197	* immediate subnodes, so in this case we would get the FDT_BEGIN_NODE and
198	* FDT_END_NODE of all subnodes of /.
199	*
200	* The subnode feature helps in a hashing situation since it prevents the
201	* root node from changing at all. Any change to non-excluded properties,
202	* names of subnodes or number of subnodes would be detected.
203	*
204	* When used with FITs this provides the ability to hash and sign parts of
205	* the FIT based on different configurations in the FIT. Then it is
206	* impossible to change anything about that configuration (include images
207	* attached to the configuration), but it may be possible to add new
208	* configurations, new images or new signatures within the existing
209	* framework.
210	*
211	* Adding new properties to a device tree may result in the string table
212	* being extended (if the new property names are different from those
213	* already added). This function can optionally include a region for
214	* the string table so that this can be part of the hash too. This is always
215	* the last region.
216	*
217	* The FDT also has a mem_rsvmap table which can also be included, and is
218	* always the first region if so.
219	*
220	* The device tree header is not included in the region list. Since the
221	* contents of the FDT are changing (shrinking, often), the caller will need
222	* to regenerate the header anyway.
223	*
224	* @fdt: Device tree to check
225	* @h_include: Function to call to determine whether to include a part or
226	* not:
227	*
228	* @priv: Private pointer as passed to fdt_find_regions()
229	* @fdt: Pointer to FDT blob
230	* @offset: Offset of this node / property
231	* @type: Type of this part, FDT_IS_...
232	* @data: Pointer to data (node name, property name, compatible
233	* string, value (not yet supported)
234	* @size: Size of data, or 0 if none
235	* @return 0 to exclude, 1 to include, -1 if no information is
236	* available
237	* @priv: Private pointer passed to h_include
238	* @region: Returns list of regions, sorted by offset
239	* @max_regions: Maximum length of region list
240	* @path: Pointer to a temporary string for the function to use for
241	* building path names
242	* @path_len: Length of path, must be large enough to hold the longest
243	* path in the tree
244	* @flags: Various flags that control the region algortihm, see
245	* FDT_REG_...
246	* @return number of regions in list. If this is >max_regions then the
247	* region array was exhausted. You should increase max_regions and try
248	* the call again. Only the first max_regions elements are available in the
249	* array.
250	*
251	* On error a -ve value is return, which can be:
252	*
253	* -FDT_ERR_BADSTRUCTURE (too deep or more END tags than BEGIN tags
254	* -FDT_ERR_BADLAYOUT
255	* -FDT_ERR_NOSPACE (path area is too small)
256	*/
257	int fdt_first_region(const void *fdt,
258	int (h_include)(void priv, const void *fdt, int offset,
259	int type, const char *data, int size),
260	void priv, struct fdt_region region,
261	char *path, int path_len, int flags,
262	struct fdt_region_state *info);
263
264	/** fdt_next_region() - find next region
265	*
266	* See fdt_first_region() for full description. This function finds the
267	* next region according to the provided parameters, which must be the same
268	* as passed to fdt_first_region().
269	*
270	* This function can additionally return -FDT_ERR_NOTFOUND when there are no
271	* more regions
272	*/
273	int fdt_next_region(const void *fdt,
274	int (h_include)(void priv, const void *fdt, int offset,
275	int type, const char *data, int size),
276	void priv, struct fdt_region region,
277	char *path, int path_len, int flags,
278	struct fdt_region_state *info);
279
280	/**
281	* fdt_add_alias_regions() - find aliases that point to existing regions
282	*
283	* Once a device tree grep is complete some of the nodes will be present
284	* and some will have been dropped. This function checks all the alias nodes
285	* to figure out which points point to nodes which are still present. These
286	* aliases need to be kept, along with the nodes they reference.
287	*
288	* Given a list of regions function finds the aliases that still apply and
289	* adds more regions to the list for these. This function is called after
290	* fdt_next_region() has finished returning regions and requires the same
291	* state.
292	*
293	* @fdt: Device tree file to reference
294	* @region: List of regions that will be kept
295	* @count: Number of regions
296	* @max_regions: Number of entries that can fit in @region
297	* @info: Region state as returned from fdt_next_region()
298	* @return new number of regions in @region (i.e. count + the number added)
299	* or -FDT_ERR_NOSPACE if there was not enough space.
300	*/
301	int fdt_add_alias_regions(const void fdt, struct fdt_region region, int count,
302	int max_regions, struct fdt_region_state *info);
303	#endif /* SWIG */
304
305	#endif /* _FDT_REGION_H */