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https://github.com/brain-hackers/u-boot-brain
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493 lines
14 KiB
C
493 lines
14 KiB
C
![]() |
/*
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* libfdt - Flat Device Tree manipulation
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* Copyright (C) 2013 Google, Inc
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* Written by Simon Glass <sjg@chromium.org>
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* SPDX-License-Identifier: GPL-2.0+ BSD-2-Clause
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*/
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#include "libfdt_env.h"
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#ifndef USE_HOSTCC
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#include <fdt.h>
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#include <libfdt.h>
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#else
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#include "fdt_host.h"
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#endif
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#include "libfdt_internal.h"
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/**
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* fdt_add_region() - Add a new region to our list
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*
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* The region is added if there is space, but in any case we increment the
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* count. If permitted, and the new region overlaps the last one, we merge
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* them.
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*
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* @info: State information
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* @offset: Start offset of region
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* @size: Size of region
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*/
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static int fdt_add_region(struct fdt_region_state *info, int offset, int size)
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{
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struct fdt_region *reg;
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reg = info->region ? &info->region[info->count - 1] : NULL;
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if (info->can_merge && info->count &&
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info->count <= info->max_regions &&
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reg && offset <= reg->offset + reg->size) {
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reg->size = offset + size - reg->offset;
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} else if (info->count++ < info->max_regions) {
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if (reg) {
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reg++;
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reg->offset = offset;
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reg->size = size;
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}
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} else {
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return -1;
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}
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return 0;
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}
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static int region_list_contains_offset(struct fdt_region_state *info,
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const void *fdt, int target)
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{
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struct fdt_region *reg;
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int num;
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target += fdt_off_dt_struct(fdt);
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for (reg = info->region, num = 0; num < info->count; reg++, num++) {
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if (target >= reg->offset && target < reg->offset + reg->size)
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return 1;
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}
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return 0;
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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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{
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int base = fdt_off_dt_struct(fdt);
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int node, node_end, offset;
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int did_alias_header;
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node = fdt_subnode_offset(fdt, 0, "aliases");
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if (node < 0)
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return -FDT_ERR_NOTFOUND;
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/* The aliases node must come before the others */
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node_end = fdt_next_subnode(fdt, node);
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if (node_end <= 0)
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return -FDT_ERR_BADLAYOUT;
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node_end -= sizeof(fdt32_t);
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did_alias_header = 0;
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info->region = region;
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info->count = count;
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info->can_merge = 0;
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info->max_regions = max_regions;
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for (offset = fdt_first_property_offset(fdt, node);
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offset >= 0;
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offset = fdt_next_property_offset(fdt, offset)) {
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const struct fdt_property *prop;
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const char *name;
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int target, next;
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prop = fdt_get_property_by_offset(fdt, offset, NULL);
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name = fdt_string(fdt, fdt32_to_cpu(prop->nameoff));
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target = fdt_path_offset(fdt, name);
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if (!region_list_contains_offset(info, fdt, target))
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continue;
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next = fdt_next_property_offset(fdt, offset);
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if (next < 0)
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next = node_end - sizeof(fdt32_t);
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if (!did_alias_header) {
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fdt_add_region(info, base + node, 12);
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did_alias_header = 1;
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}
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fdt_add_region(info, base + offset, next - offset);
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}
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/* Add the 'end' tag */
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if (did_alias_header)
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fdt_add_region(info, base + node_end, sizeof(fdt32_t));
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return info->count < max_regions ? info->count : -FDT_ERR_NOSPACE;
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}
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/**
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* fdt_include_supernodes() - Include supernodes required by this node
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*
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* When we decided to include a node or property which is not at the top
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* level, this function forces the inclusion of higher level nodes. For
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* example, given this tree:
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*
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* / {
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* testing {
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* }
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* }
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*
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* If we decide to include testing then we need the root node to have a valid
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* tree. This function adds those regions.
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*
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* @info: State information
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* @depth: Current stack depth
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*/
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static int fdt_include_supernodes(struct fdt_region_state *info, int depth)
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{
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int base = fdt_off_dt_struct(info->fdt);
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int start, stop_at;
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int i;
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/*
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* Work down the stack looking for supernodes that we didn't include.
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* The algortihm here is actually pretty simple, since we know that
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* no previous subnode had to include these nodes, or if it did, we
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* marked them as included (on the stack) already.
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*/
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for (i = 0; i <= depth; i++) {
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if (!info->stack[i].included) {
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start = info->stack[i].offset;
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/* Add the FDT_BEGIN_NODE tag of this supernode */
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fdt_next_tag(info->fdt, start, &stop_at);
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if (fdt_add_region(info, base + start, stop_at - start))
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return -1;
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/* Remember that this supernode is now included */
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info->stack[i].included = 1;
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info->can_merge = 1;
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}
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/* Force (later) generation of the FDT_END_NODE tag */
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if (!info->stack[i].want)
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info->stack[i].want = WANT_NODES_ONLY;
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}
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return 0;
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}
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enum {
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FDT_DONE_NOTHING,
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FDT_DONE_MEM_RSVMAP,
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FDT_DONE_STRUCT,
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FDT_DONE_END,
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FDT_DONE_STRINGS,
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FDT_DONE_ALL,
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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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{
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struct fdt_region_ptrs *p = &info->ptrs;
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/* Set up our state */
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info->fdt = fdt;
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info->can_merge = 1;
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info->max_regions = 1;
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info->start = -1;
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p->want = WANT_NOTHING;
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p->end = path;
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*p->end = '\0';
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p->nextoffset = 0;
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p->depth = -1;
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p->done = FDT_DONE_NOTHING;
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return fdt_next_region(fdt, h_include, priv, region,
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path, path_len, flags, info);
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}
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/*
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* Theory of operation
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*
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*
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*
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Note: in this description 'included' means that a node (or other part of
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the tree) should be included in the region list, i.e. it will have a region
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which covers its part of the tree.
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This function maintains some state from the last time it is called. It
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checks the next part of the tree that it is supposed to look at
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(p.nextoffset) to see if that should be included or not. When it finds
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something to include, it sets info->start to its offset. This marks the
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start of the region we want to include.
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Once info->start is set to the start (i.e. not -1), we continue scanning
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until we find something that we don't want included. This will be the end
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of a region. At this point we can close off the region and add it to the
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list. So we do so, and reset info->start to -1.
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One complication here is that we want to merge regions. So when we come to
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add another region later, we may in fact merge it with the previous one if
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one ends where the other starts.
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The function fdt_add_region() will return -1 if it fails to add the region,
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because we already have a region ready to be returned, and the new one
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cannot be merged in with it. In this case, we must return the region we
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found, and wait for another call to this function. When it comes, we will
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repeat the processing of the tag and again try to add a region. This time it
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will succeed.
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The current state of the pointers (stack, offset, etc.) is maintained in
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a ptrs member. At the start of every loop iteration we make a copy of it.
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The copy is then updated as the tag is processed. Only if we get to the end
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of the loop iteration (and successfully call fdt_add_region() if we need
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to) can we commit the changes we have made to these pointers. For example,
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if we see an FDT_END_NODE tag we will decrement the depth value. But if we
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need to add a region for this tag (let's say because the previous tag is
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included and this FDT_END_NODE tag is not included) then we will only commit
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the result if we were able to add the region. That allows us to retry again
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next time.
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We keep track of a variable called 'want' which tells us what we want to
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include when there is no specific information provided by the h_include
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function for a particular property. This basically handles the inclusion of
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properties which are pulled in by virtue of the node they are in. So if you
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include a node, its properties are also included. In this case 'want' will
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be WANT_NODES_AND_PROPS. The FDT_REG_DIRECT_SUBNODES feature also makes use
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of 'want'. While we are inside the subnode, 'want' will be set to
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WANT_NODES_ONLY, so that only the subnode's FDT_BEGIN_NODE and FDT_END_NODE
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tags will be included, and properties will be skipped. If WANT_NOTHING is
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selected, then we will just rely on what the h_include() function tells us.
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Using 'want' we work out 'include', which tells us whether this current tag
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should be included or not. As you can imagine, if the value of 'include'
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changes, that means we are on a boundary between nodes to include and nodes
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to exclude. At this point we either close off a previous region and add it
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to the list, or mark the start of a new region.
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Apart from the nodes, we have mem_rsvmap, the FDT_END tag and the string
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list. Each of these dealt with as a whole (i.e. we create a region for each
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if it is to be included). For mem_rsvmap we don't allow it to merge with
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the first struct region. For the stringlist we don't allow it to merge with
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the last struct region (which contains at minimum the FDT_END tag).
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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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int base = fdt_off_dt_struct(fdt);
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int last_node = 0;
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const char *str;
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info->region = region;
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info->count = 0;
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if (info->ptrs.done < FDT_DONE_MEM_RSVMAP &&
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(flags & FDT_REG_ADD_MEM_RSVMAP)) {
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/* Add the memory reserve map into its own region */
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if (fdt_add_region(info, fdt_off_mem_rsvmap(fdt),
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fdt_off_dt_struct(fdt) -
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fdt_off_mem_rsvmap(fdt)))
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return 0;
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info->can_merge = 0; /* Don't allow merging with this */
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info->ptrs.done = FDT_DONE_MEM_RSVMAP;
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}
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/*
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* Work through the tags one by one, deciding whether each needs to
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* be included or not. We set the variable 'include' to indicate our
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* decision. 'want' is used to track what we want to include - it
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* allows us to pick up all the properties (and/or subnode tags) of
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* a node.
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*/
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while (info->ptrs.done < FDT_DONE_STRUCT) {
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const struct fdt_property *prop;
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struct fdt_region_ptrs p;
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const char *name;
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int include = 0;
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int stop_at = 0;
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uint32_t tag;
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int offset;
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int val;
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int len;
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/*
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* Make a copy of our pointers. If we make it to the end of
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* this block then we will commit them back to info->ptrs.
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* Otherwise we can try again from the same starting state
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* next time we are called.
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*/
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p = info->ptrs;
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/*
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* Find the tag, and the offset of the next one. If we need to
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* stop including tags, then by default we stop *after*
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* including the current tag
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*/
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offset = p.nextoffset;
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tag = fdt_next_tag(fdt, offset, &p.nextoffset);
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stop_at = p.nextoffset;
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switch (tag) {
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case FDT_PROP:
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stop_at = offset;
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prop = fdt_get_property_by_offset(fdt, offset, NULL);
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str = fdt_string(fdt, fdt32_to_cpu(prop->nameoff));
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val = h_include(priv, fdt, last_node, FDT_IS_PROP, str,
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strlen(str) + 1);
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if (val == -1) {
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include = p.want >= WANT_NODES_AND_PROPS;
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} else {
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include = val;
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/*
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* Make sure we include the } for this block.
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* It might be more correct to have this done
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* by the call to fdt_include_supernodes() in
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* the case where it adds the node we are
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* currently in, but this is equivalent.
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*/
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if ((flags & FDT_REG_SUPERNODES) && val &&
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!p.want)
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p.want = WANT_NODES_ONLY;
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}
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/* Value grepping is not yet supported */
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break;
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case FDT_NOP:
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include = p.want >= WANT_NODES_AND_PROPS;
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stop_at = offset;
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break;
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case FDT_BEGIN_NODE:
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last_node = offset;
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p.depth++;
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if (p.depth == FDT_MAX_DEPTH)
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return -FDT_ERR_TOODEEP;
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name = fdt_get_name(fdt, offset, &len);
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if (p.end - path + 2 + len >= path_len)
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return -FDT_ERR_NOSPACE;
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/* Build the full path of this node */
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if (p.end != path + 1)
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*p.end++ = '/';
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strcpy(p.end, name);
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p.end += len;
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info->stack[p.depth].want = p.want;
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info->stack[p.depth].offset = offset;
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/*
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* If we are not intending to include this node unless
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* it matches, make sure we stop *before* its tag.
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*/
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if (p.want == WANT_NODES_ONLY ||
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!(flags & (FDT_REG_DIRECT_SUBNODES |
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FDT_REG_ALL_SUBNODES))) {
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stop_at = offset;
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p.want = WANT_NOTHING;
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}
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val = h_include(priv, fdt, offset, FDT_IS_NODE, path,
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p.end - path + 1);
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/* Include this if requested */
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if (val) {
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p.want = (flags & FDT_REG_ALL_SUBNODES) ?
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WANT_ALL_NODES_AND_PROPS :
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WANT_NODES_AND_PROPS;
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}
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/* If not requested, decay our 'p.want' value */
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else if (p.want) {
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if (p.want != WANT_ALL_NODES_AND_PROPS)
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p.want--;
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/* Not including this tag, so stop now */
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} else {
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stop_at = offset;
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}
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/*
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* Decide whether to include this tag, and update our
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* stack with the state for this node
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*/
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include = p.want;
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info->stack[p.depth].included = include;
|
||
|
break;
|
||
|
|
||
|
case FDT_END_NODE:
|
||
|
include = p.want;
|
||
|
if (p.depth < 0)
|
||
|
return -FDT_ERR_BADSTRUCTURE;
|
||
|
|
||
|
/*
|
||
|
* If we don't want this node, stop right away, unless
|
||
|
* we are including subnodes
|
||
|
*/
|
||
|
if (!p.want && !(flags & FDT_REG_DIRECT_SUBNODES))
|
||
|
stop_at = offset;
|
||
|
p.want = info->stack[p.depth].want;
|
||
|
p.depth--;
|
||
|
while (p.end > path && *--p.end != '/')
|
||
|
;
|
||
|
*p.end = '\0';
|
||
|
break;
|
||
|
|
||
|
case FDT_END:
|
||
|
/* We always include the end tag */
|
||
|
include = 1;
|
||
|
p.done = FDT_DONE_STRUCT;
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
/* If this tag is to be included, mark it as region start */
|
||
|
if (include && info->start == -1) {
|
||
|
/* Include any supernodes required by this one */
|
||
|
if (flags & FDT_REG_SUPERNODES) {
|
||
|
if (fdt_include_supernodes(info, p.depth))
|
||
|
return 0;
|
||
|
}
|
||
|
info->start = offset;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* If this tag is not to be included, finish up the current
|
||
|
* region.
|
||
|
*/
|
||
|
if (!include && info->start != -1) {
|
||
|
if (fdt_add_region(info, base + info->start,
|
||
|
stop_at - info->start))
|
||
|
return 0;
|
||
|
info->start = -1;
|
||
|
info->can_merge = 1;
|
||
|
}
|
||
|
|
||
|
/* If we have made it this far, we can commit our pointers */
|
||
|
info->ptrs = p;
|
||
|
}
|
||
|
|
||
|
/* Add a region for the END tag and a separate one for string table */
|
||
|
if (info->ptrs.done < FDT_DONE_END) {
|
||
|
if (info->ptrs.nextoffset != fdt_size_dt_struct(fdt))
|
||
|
return -FDT_ERR_BADSTRUCTURE;
|
||
|
|
||
|
if (fdt_add_region(info, base + info->start,
|
||
|
info->ptrs.nextoffset - info->start))
|
||
|
return 0;
|
||
|
info->ptrs.done++;
|
||
|
}
|
||
|
if (info->ptrs.done < FDT_DONE_STRINGS) {
|
||
|
if (flags & FDT_REG_ADD_STRING_TAB) {
|
||
|
info->can_merge = 0;
|
||
|
if (fdt_off_dt_strings(fdt) <
|
||
|
base + info->ptrs.nextoffset)
|
||
|
return -FDT_ERR_BADLAYOUT;
|
||
|
if (fdt_add_region(info, fdt_off_dt_strings(fdt),
|
||
|
fdt_size_dt_strings(fdt)))
|
||
|
return 0;
|
||
|
}
|
||
|
info->ptrs.done++;
|
||
|
}
|
||
|
|
||
|
return info->count > 0 ? 0 : -FDT_ERR_NOTFOUND;
|
||
|
}
|