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c960a68e20
This macro is locally referenced in common/image-fdt.c Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Simon Glass <sjg@chromium.org>
313 lines
13 KiB
C
313 lines
13 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _INCLUDE_LIBFDT_H_
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#define _INCLUDE_LIBFDT_H_
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#ifndef USE_HOSTCC
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#include <linux/libfdt_env.h>
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#endif
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#include "../../scripts/dtc/libfdt/libfdt.h"
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/* U-Boot local hacks */
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#ifndef SWIG /* Not available in Python */
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struct fdt_region {
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int offset;
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int size;
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};
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/*
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* Flags for fdt_find_regions()
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*
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* Add a region for the string table (always the last region)
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*/
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#define FDT_REG_ADD_STRING_TAB (1 << 0)
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/*
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* Add all supernodes of a matching node/property, useful for creating a
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* valid subset tree
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*/
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#define FDT_REG_SUPERNODES (1 << 1)
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/* Add the FDT_BEGIN_NODE tags of subnodes, including their names */
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#define FDT_REG_DIRECT_SUBNODES (1 << 2)
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/* Add all subnodes of a matching node */
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#define FDT_REG_ALL_SUBNODES (1 << 3)
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/* Add a region for the mem_rsvmap table (always the first region) */
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#define FDT_REG_ADD_MEM_RSVMAP (1 << 4)
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/* Indicates what an fdt part is (node, property, value) */
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#define FDT_IS_NODE (1 << 0)
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#define FDT_IS_PROP (1 << 1)
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#define FDT_IS_VALUE (1 << 2) /* not supported */
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#define FDT_IS_COMPAT (1 << 3) /* used internally */
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#define FDT_NODE_HAS_PROP (1 << 4) /* node contains prop */
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#define FDT_ANY_GLOBAL (FDT_IS_NODE | FDT_IS_PROP | FDT_IS_VALUE | \
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FDT_IS_COMPAT)
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#define FDT_IS_ANY 0x1f /* all the above */
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/* We set a reasonable limit on the number of nested nodes */
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#define FDT_MAX_DEPTH 32
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/* Decribes what we want to include from the current tag */
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enum want_t {
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WANT_NOTHING,
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WANT_NODES_ONLY, /* No properties */
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WANT_NODES_AND_PROPS, /* Everything for one level */
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WANT_ALL_NODES_AND_PROPS /* Everything for all levels */
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};
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/* Keeps track of the state at parent nodes */
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struct fdt_subnode_stack {
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int offset; /* Offset of node */
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enum want_t want; /* The 'want' value here */
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int included; /* 1 if we included this node, 0 if not */
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};
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struct fdt_region_ptrs {
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int depth; /* Current tree depth */
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int done; /* What we have completed scanning */
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enum want_t want; /* What we are currently including */
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char *end; /* Pointer to end of full node path */
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int nextoffset; /* Next node offset to check */
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};
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/* The state of our finding algortihm */
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struct fdt_region_state {
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struct fdt_subnode_stack stack[FDT_MAX_DEPTH]; /* node stack */
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struct fdt_region *region; /* Contains list of regions found */
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int count; /* Numnber of regions found */
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const void *fdt; /* FDT blob */
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int max_regions; /* Maximum regions to find */
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int can_merge; /* 1 if we can merge with previous region */
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int start; /* Start position of current region */
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struct fdt_region_ptrs ptrs; /* Pointers for what we are up to */
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};
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/**
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* fdt_find_regions() - find regions in device tree
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*
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* Given a list of nodes to include and properties to exclude, find
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* the regions of the device tree which describe those included parts.
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*
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* The intent is to get a list of regions which will be invariant provided
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* those parts are invariant. For example, if you request a list of regions
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* for all nodes but exclude the property "data", then you will get the
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* same region contents regardless of any change to "data" properties.
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*
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* This function can be used to produce a byte-stream to send to a hashing
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* function to verify that critical parts of the FDT have not changed.
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*
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* Nodes which are given in 'inc' are included in the region list, as
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* are the names of the immediate subnodes nodes (but not the properties
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* or subnodes of those subnodes).
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*
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* For eaxample "/" means to include the root node, all root properties
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* and the FDT_BEGIN_NODE and FDT_END_NODE of all subnodes of /. The latter
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* ensures that we capture the names of the subnodes. In a hashing situation
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* it prevents the root node from changing at all Any change to non-excluded
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* properties, names of subnodes or number of subnodes would be detected.
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*
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* When used with FITs this provides the ability to hash and sign parts of
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* the FIT based on different configurations in the FIT. Then it is
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* impossible to change anything about that configuration (include images
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* attached to the configuration), but it may be possible to add new
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* configurations, new images or new signatures within the existing
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* framework.
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*
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* Adding new properties to a device tree may result in the string table
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* being extended (if the new property names are different from those
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* already added). This function can optionally include a region for
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* the string table so that this can be part of the hash too.
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*
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* The device tree header is not included in the list.
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*
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* @fdt: Device tree to check
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* @inc: List of node paths to included
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* @inc_count: Number of node paths in list
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* @exc_prop: List of properties names to exclude
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* @exc_prop_count: Number of properties in exclude list
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* @region: Returns list of regions
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* @max_region: Maximum length of region list
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* @path: Pointer to a temporary string for the function to use for
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* building path names
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* @path_len: Length of path, must be large enough to hold the longest
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* path in the tree
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* @add_string_tab: 1 to add a region for the string table
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* @return number of regions in list. If this is >max_regions then the
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* region array was exhausted. You should increase max_regions and try
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* the call again.
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*/
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int fdt_find_regions(const void *fdt, char * const inc[], int inc_count,
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char * const exc_prop[], int exc_prop_count,
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struct fdt_region region[], int max_regions,
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char *path, int path_len, int add_string_tab);
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/**
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* fdt_first_region() - find regions in device tree
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*
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* Given a nodes and properties to include and properties to exclude, find
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* the regions of the device tree which describe those included parts.
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*
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* The use for this function is twofold. Firstly it provides a convenient
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* way of performing a structure-aware grep of the tree. For example it is
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* possible to grep for a node and get all the properties associated with
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* that node. Trees can be subsetted easily, by specifying the nodes that
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* are required, and then writing out the regions returned by this function.
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* This is useful for small resource-constrained systems, such as boot
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* loaders, which want to use an FDT but do not need to know about all of
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* it.
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*
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* Secondly it makes it easy to hash parts of the tree and detect changes.
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* The intent is to get a list of regions which will be invariant provided
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* those parts are invariant. For example, if you request a list of regions
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* for all nodes but exclude the property "data", then you will get the
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* same region contents regardless of any change to "data" properties.
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*
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* This function can be used to produce a byte-stream to send to a hashing
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* function to verify that critical parts of the FDT have not changed.
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* Note that semantically null changes in order could still cause false
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* hash misses. Such reordering might happen if the tree is regenerated
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* from source, and nodes are reordered (the bytes-stream will be emitted
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* in a different order and many hash functions will detect this). However
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* if an existing tree is modified using libfdt functions, such as
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* fdt_add_subnode() and fdt_setprop(), then this problem is avoided.
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*
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* The nodes/properties to include/exclude are defined by a function
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* provided by the caller. This function is called for each node and
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* property, and must return:
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*
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* 0 - to exclude this part
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* 1 - to include this part
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* -1 - for FDT_IS_PROP only: no information is available, so include
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* if its containing node is included
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*
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* The last case is only used to deal with properties. Often a property is
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* included if its containing node is included - this is the case where
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* -1 is returned.. However if the property is specifically required to be
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* included/excluded, then 0 or 1 can be returned. Note that including a
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* property when the FDT_REG_SUPERNODES flag is given will force its
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* containing node to be included since it is not valid to have a property
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* that is not in a node.
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*
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* Using the information provided, the inclusion of a node can be controlled
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* either by a node name or its compatible string, or any other property
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* that the function can determine.
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*
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* As an example, including node "/" means to include the root node and all
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* root properties. A flag provides a way of also including supernodes (of
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* which there is none for the root node), and another flag includes
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* immediate subnodes, so in this case we would get the FDT_BEGIN_NODE and
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* FDT_END_NODE of all subnodes of /.
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*
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* The subnode feature helps in a hashing situation since it prevents the
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* root node from changing at all. Any change to non-excluded properties,
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* names of subnodes or number of subnodes would be detected.
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*
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* When used with FITs this provides the ability to hash and sign parts of
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* the FIT based on different configurations in the FIT. Then it is
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* impossible to change anything about that configuration (include images
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* attached to the configuration), but it may be possible to add new
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* configurations, new images or new signatures within the existing
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* framework.
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*
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* Adding new properties to a device tree may result in the string table
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* being extended (if the new property names are different from those
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* already added). This function can optionally include a region for
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* the string table so that this can be part of the hash too. This is always
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* the last region.
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*
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* The FDT also has a mem_rsvmap table which can also be included, and is
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* always the first region if so.
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*
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* The device tree header is not included in the region list. Since the
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* contents of the FDT are changing (shrinking, often), the caller will need
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* to regenerate the header anyway.
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*
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* @fdt: Device tree to check
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* @h_include: Function to call to determine whether to include a part or
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* not:
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*
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* @priv: Private pointer as passed to fdt_find_regions()
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* @fdt: Pointer to FDT blob
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* @offset: Offset of this node / property
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* @type: Type of this part, FDT_IS_...
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* @data: Pointer to data (node name, property name, compatible
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* string, value (not yet supported)
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* @size: Size of data, or 0 if none
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* @return 0 to exclude, 1 to include, -1 if no information is
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* available
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* @priv: Private pointer passed to h_include
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* @region: Returns list of regions, sorted by offset
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* @max_regions: Maximum length of region list
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* @path: Pointer to a temporary string for the function to use for
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* building path names
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* @path_len: Length of path, must be large enough to hold the longest
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* path in the tree
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* @flags: Various flags that control the region algortihm, see
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* FDT_REG_...
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* @return number of regions in list. If this is >max_regions then the
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* region array was exhausted. You should increase max_regions and try
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* the call again. Only the first max_regions elements are available in the
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* array.
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*
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* On error a -ve value is return, which can be:
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*
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* -FDT_ERR_BADSTRUCTURE (too deep or more END tags than BEGIN tags
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* -FDT_ERR_BADLAYOUT
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* -FDT_ERR_NOSPACE (path area is too small)
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*/
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int fdt_first_region(const void *fdt,
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int (*h_include)(void *priv, const void *fdt, int offset,
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int type, const char *data, int size),
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void *priv, struct fdt_region *region,
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char *path, int path_len, int flags,
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struct fdt_region_state *info);
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/** fdt_next_region() - find next region
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*
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* See fdt_first_region() for full description. This function finds the
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* next region according to the provided parameters, which must be the same
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* as passed to fdt_first_region().
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*
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* This function can additionally return -FDT_ERR_NOTFOUND when there are no
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* more regions
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*/
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int fdt_next_region(const void *fdt,
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int (*h_include)(void *priv, const void *fdt, int offset,
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int type, const char *data, int size),
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void *priv, struct fdt_region *region,
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char *path, int path_len, int flags,
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struct fdt_region_state *info);
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/**
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* fdt_add_alias_regions() - find aliases that point to existing regions
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*
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* Once a device tree grep is complete some of the nodes will be present
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* and some will have been dropped. This function checks all the alias nodes
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* to figure out which points point to nodes which are still present. These
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* aliases need to be kept, along with the nodes they reference.
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*
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* Given a list of regions function finds the aliases that still apply and
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* adds more regions to the list for these. This function is called after
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* fdt_next_region() has finished returning regions and requires the same
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* state.
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*
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* @fdt: Device tree file to reference
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* @region: List of regions that will be kept
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* @count: Number of regions
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* @max_regions: Number of entries that can fit in @region
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* @info: Region state as returned from fdt_next_region()
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* @return new number of regions in @region (i.e. count + the number added)
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* or -FDT_ERR_NOSPACE if there was not enough space.
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*/
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int fdt_add_alias_regions(const void *fdt, struct fdt_region *region, int count,
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int max_regions, struct fdt_region_state *info);
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#endif /* SWIG */
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extern struct fdt_header *working_fdt; /* Pointer to the working fdt */
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#endif /* _INCLUDE_LIBFDT_H_ */
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