// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
/*
* libfdt - Flat Device Tree manipulation
* Copyright (C) 2016 Free Electrons
* Copyright (C) 2016 NextThing Co.
*/
#include "libfdt_env.h"
#include <fdt.h>
#include <libfdt.h>
#include "libfdt_internal.h"
/**
* overlay_get_target_phandle - retrieves the target phandle of a fragment
* @fdto: pointer to the device tree overlay blob
* @fragment: node offset of the fragment in the overlay
*
* overlay_get_target_phandle() retrieves the target phandle of an
* overlay fragment when that fragment uses a phandle (target
* property) instead of a path (target-path property).
*
* returns:
* the phandle pointed by the target property
* 0, if the phandle was not found
* -1, if the phandle was malformed
*/
static uint32_t overlay_get_target_phandle(const void *fdto, int fragment)
{
const fdt32_t *val;
int len;
val = fdt_getprop(fdto, fragment, "target", &len);
if (!val)
return 0;
if ((len != sizeof(*val)) || (fdt32_to_cpu(*val) == (uint32_t)-1))
return (uint32_t)-1;
return fdt32_to_cpu(*val);
}
int fdt_overlay_target_offset(const void *fdt, const void *fdto,
int fragment_offset, char const **pathp)
{
uint32_t phandle;
const char *path = NULL;
int path_len = 0, ret;
/* Try first to do a phandle based lookup */
phandle = overlay_get_target_phandle(fdto, fragment_offset);
if (phandle == (uint32_t)-1)
return -FDT_ERR_BADPHANDLE;
/* no phandle, try path */
if (!phandle) {
/* And then a path based lookup */
path = fdt_getprop(fdto, fragment_offset, "target-path", &path_len);
if (path)
ret = fdt_path_offset(fdt, path);
else
ret = path_len;
} else
ret = fdt_node_offset_by_phandle(fdt, phandle);
/*
* If we haven't found either a target or a
* target-path property in a node that contains a
* __overlay__ subnode (we wouldn't be called
* otherwise), consider it a improperly written
* overlay
*/
if (ret < 0 && path_len == -FDT_ERR_NOTFOUND)
ret = -FDT_ERR_BADOVERLAY;
/* return on error */
if (ret < 0)
return ret;
/* return pointer to path (if available) */
if (pathp)
*pathp = path ? path : NULL;
return ret;
}
/**
* overlay_phandle_add_offset - Increases a phandle by an offset
* @fdt: Base device tree blob
* @node: Device tree overlay blob
* @name: Name of the property to modify (phandle or linux,phandle)
* @delta: offset to apply
*
* overlay_phandle_add_offset() increments a node phandle by a given
* offset.
*
* returns:
* 0 on success.
* Negative error code on error
*/
static int overlay_phandle_add_offset(void *fdt, int node,
const char *name, uint32_t delta)
{
fdt32_t *valp, val;
int len;
valp = fdt_getprop_w(fdt, node, name, &len);
if (!valp)
return len;
if (len != sizeof(val))
return -FDT_ERR_BADPHANDLE;
val = fdt32_ld(valp);
if (val + delta < val || val + delta == (uint32_t)-1)
return -FDT_ERR_NOPHANDLES;
fdt32_st(valp, val + delta);
return 0;
}
/**
* overlay_adjust_node_phandles - Offsets the phandles of a node
* @fdto: Device tree overlay blob
* @node: Offset of the node we want to adjust
* @delta: Offset to shift the phandles of
*
* overlay_adjust_node_phandles() adds a constant to all the phandles
* of a given node. This is mainly use as part of the overlay
* application process, when we want to update all the overlay
* phandles to not conflict with the overlays of the base device tree.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_adjust_node_phandles(void *fdto, int node,
uint32_t delta)
{
int child;
int ret;
ret = overlay_phandle_add_offset(fdto, node, "phandle", delta);
if (ret && ret != -FDT_ERR_NOTFOUND)
return ret;
ret = overlay_phandle_add_offset(fdto, node, "linux,phandle", delta);
if (ret && ret != -FDT_ERR_NOTFOUND)
return ret;
fdt_for_each_subnode(child, fdto, node) {
ret = overlay_adjust_node_phandles(fdto, child, delta);
if (ret)
return ret;
}
return 0;
}
/**
* overlay_adjust_local_phandles - Adjust the phandles of a whole overlay
* @fdto: Device tree overlay blob
* @delta: Offset to shift the phandles of
*
* overlay_adjust_local_phandles() adds a constant to all the
* phandles of an overlay. This is mainly use as part of the overlay
* application process, when we want to update all the overlay
* phandles to not conflict with the overlays of the base device tree.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_adjust_local_phandles(void *fdto, uint32_t delta)
{
/*
* Start adjusting the phandles from the overlay root
*/
return overlay_adjust_node_phandles(fdto, 0, delta);
}
/**
* overlay_update_local_node_references - Adjust the overlay references
* @fdto: Device tree overlay blob
* @tree_node: Node offset of the node to operate on
* @fixup_node: Node offset of the matching local fixups node
* @delta: Offset to shift the phandles of
*
* overlay_update_local_nodes_references() update the phandles
* pointing to a node within the device tree overlay by adding a
* constant delta.
*
* This is mainly used as part of a device tree application process,
* where you want the device tree overlays phandles to not conflict
* with the ones from the base device tree before merging them.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_update_local_node_references(void *fdto,
int tree_node,
int fixup_node,
uint32_t delta)
{
int fixup_prop;
int fixup_child;
int ret;
fdt_for_each_property_offset(fixup_prop, fdto, fixup_node) {
const fdt32_t *fixup_val;
const char *name;
char *tree_val;
int fixup_len;
int tree_len;
int i;
fixup_val = fdt_getprop_by_offset(fdto, fixup_prop,
&name, &fixup_len);
if (!fixup_val)
return fixup_len;
if (fixup_len % sizeof(uint32_t))
return -FDT_ERR_BADOVERLAY;
fixup_len /= sizeof(uint32_t);
tree_val = fdt_getprop_w(fdto, tree_node, name, &tree_len);
if (!tree_val) {
if (tree_len == -FDT_ERR_NOTFOUND)
return -FDT_ERR_BADOVERLAY;
return tree_len;
}
for (i = 0; i < fixup_len; i++) {
fdt32_t *refp;
refp = (fdt32_t *)(tree_val + fdt32_ld_(fixup_val + i));
/*
* phandles to fixup can be unaligned, so use
* fdt32_{ld,st}() to read/write them.
*/
fdt32_st(refp, fdt32_ld(refp) + delta);
}
}
fdt_for_each_subnode(fixup_child, fdto, fixup_node) {
const char *fixup_child_name = fdt_get_name(fdto, fixup_child,
NULL);
int tree_child;
tree_child = fdt_subnode_offset(fdto, tree_node,
fixup_child_name);
if (tree_child == -FDT_ERR_NOTFOUND)
return -FDT_ERR_BADOVERLAY;
if (tree_child < 0)
return tree_child;
ret = overlay_update_local_node_references(fdto,
tree_child,
fixup_child,
delta);
if (ret)
return ret;
}
return 0;
}
/**
* overlay_update_local_references - Adjust the overlay references
* @fdto: Device tree overlay blob
* @delta: Offset to shift the phandles of
*
* overlay_update_local_references() update all the phandles pointing
* to a node within the device tree overlay by adding a constant
* delta to not conflict with the base overlay.
*
* This is mainly used as part of a device tree application process,
* where you want the device tree overlays phandles to not conflict
* with the ones from the base device tree before merging them.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_update_local_references(void *fdto, uint32_t delta)
{
int fixups;
fixups = fdt_path_offset(fdto, "/__local_fixups__");
if (fixups < 0) {
/* There's no local phandles to adjust, bail out */
if (fixups == -FDT_ERR_NOTFOUND)
return 0;
return fixups;
}
/*
* Update our local references from the root of the tree
*/
return overlay_update_local_node_references(fdto, 0, fixups,
delta);
}
/**
* overlay_fixup_one_phandle - Set an overlay phandle to the base one
* @fdt: Base Device Tree blob
* @fdto: Device tree overlay blob
* @symbols_off: Node offset of the symbols node in the base device tree
* @path: Path to a node holding a phandle in the overlay
* @path_len: number of path characters to consider
* @name: Name of the property holding the phandle reference in the overlay
* @name_len: number of name characters to consider
* @poffset: Offset within the overlay property where the phandle is stored
* @phandle: Phandle referencing the node
*
* overlay_fixup_one_phandle() resolves an overlay phandle pointing to
* a node in the base device tree.
*
* This is part of the device tree overlay application process, when
* you want all the phandles in the overlay to point to the actual
* base dt nodes.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_fixup_one_phandle(void *fdt, void *fdto,
int symbols_off,
const char *path, uint32_t path_len,
const char *name, uint32_t name_len,
int poffset, uint32_t phandle)
{
fdt32_t phandle_prop;
int fixup_off;
if (symbols_off < 0)
return symbols_off;
fixup_off = fdt_path_offset_namelen(fdto, path, path_len);
if (fixup_off == -FDT_ERR_NOTFOUND)
return -FDT_ERR_BADOVERLAY;
if (fixup_off < 0)
return fixup_off;
phandle_prop = cpu_to_fdt32(phandle);
return fdt_setprop_inplace_namelen_partial(fdto, fixup_off,
name, name_len, poffset,
&phandle_prop,
sizeof(phandle_prop));
};
/**
* overlay_fixup_phandle - Set an overlay phandle to the base one
* @fdt: Base Device Tree blob
* @fdto: Device tree overlay blob
* @symbols_off: Node offset of the symbols node in the base device tree
* @property: Property offset in the overlay holding the list of fixups
*
* overlay_fixup_phandle() resolves all the overlay phandles pointed
* to in a __fixups__ property, and updates them to match the phandles
* in use in the base device tree.
*
* This is part of the device tree overlay application process, when
* you want all the phandles in the overlay to point to the actual
* base dt nodes.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off,
int property)
{
const char *value;
const char *label;
int len;
const char *symbol_path;
int prop_len;
int symbol_off;
uint32_t phandle;
value = fdt_getprop_by_offset(fdto, property,
&label, &len);
if (!value) {
if (len == -FDT_ERR_NOTFOUND)
return -FDT_ERR_INTERNAL;
return len;
}
symbol_path = fdt_getprop(fdt, symbols_off, label, &prop_len);
if (!symbol_path)
return prop_len;
symbol_off = fdt_path_offset(fdt, symbol_path);
if (symbol_off < 0)
return symbol_off;
phandle = fdt_get_phandle(fdt, symbol_off);
if (!phandle)
return -FDT_ERR_NOTFOUND;
do {
const char *path, *name, *fixup_end;
const char *fixup_str = value;
uint32_t path_len, name_len;
uint32_t fixup_len;
char *sep, *endptr;
int poffset, ret;
fixup_end = memchr(value, '\0', len);
if (!fixup_end)
return -FDT_ERR_BADOVERLAY;
fixup_len = fixup_end - fixup_str;
len -= fixup_len + 1;
value += fixup_len + 1;
path = fixup_str;
sep = memchr(fixup_str, ':', fixup_len);
if (!sep || *sep != ':')
return -FDT_ERR_BADOVERLAY;
path_len = sep - path;
if (path_len == (fixup_len - 1))
return -FDT_ERR_BADOVERLAY;
fixup_len -= path_len + 1;
name = sep + 1;
sep = memchr(name, ':', fixup_len);
if (!sep || *sep != ':')
return -FDT_ERR_BADOVERLAY;
name_len = sep - name;
if (!name_len)
return -FDT_ERR_BADOVERLAY;
poffset = strtoul(sep + 1, &endptr, 10);
if ((*endptr != '\0') || (endptr <= (sep + 1)))
return -FDT_ERR_BADOVERLAY;
ret = overlay_fixup_one_phandle(fdt, fdto, symbols_off,
path, path_len, name, name_len,
poffset, phandle);
if (ret)
return ret;
} while (len > 0);
return 0;
}
/**
* overlay_fixup_phandles - Resolve the overlay phandles to the base
* device tree
* @fdt: Base Device Tree blob
* @fdto: Device tree overlay blob
*
* overlay_fixup_phandles() resolves all the overlay phandles pointing
* to nodes in the base device tree.
*
* This is one of the steps of the device tree overlay application
* process, when you want all the phandles in the overlay to point to
* the actual base dt nodes.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_fixup_phandles(void *fdt, void *fdto)
{
int fixups_off, symbols_off;
int property;
/* We can have overlays without any fixups */
fixups_off = fdt_path_offset(fdto, "/__fixups__");
if (fixups_off == -FDT_ERR_NOTFOUND)
return 0; /* nothing to do */
if (fixups_off < 0)
return fixups_off;
/* And base DTs without symbols */
symbols_off = fdt_path_offset(fdt, "/__symbols__");
if ((symbols_off < 0 && (symbols_off != -FDT_ERR_NOTFOUND)))
return symbols_off;
fdt_for_each_property_offset(property, fdto, fixups_off) {
int ret;
ret = overlay_fixup_phandle(fdt, fdto, symbols_off, property);
if (ret)
return ret;
}
return 0;
}
/**
* overlay_adjust_local_conflicting_phandle: Changes a phandle value
* @fdto: Device tree overlay
* @node: The node the phandle is set for
* @fdt_phandle: The new value for the phandle
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_adjust_local_conflicting_phandle(void *fdto, int node,
uint32_t fdt_phandle)
{
const fdt32_t *php;
int len, ret;
php = fdt_getprop(fdto, node, "phandle", &len);
if (php && len == sizeof(*php)) {
ret = fdt_setprop_inplace_u32(fdto, node, "phandle", fdt_phandle);
if (ret)
return ret;
}
php = fdt_getprop(fdto, node, "linux,phandle", &len);
if (php && len == sizeof(*php)) {
ret = fdt_setprop_inplace_u32(fdto, node, "linux,phandle", fdt_phandle);
if (ret)
return ret;
}
return 0;
}
/**
* overlay_update_node_conflicting_references - Recursively replace phandle values
* @fdto: Device tree overlay blob
* @tree_node: Node to recurse into
* @fixup_node: Node offset of the matching local fixups node
* @fdt_phandle: Value to replace phandles with
* @fdto_phandle: Value to be replaced
*
* Replaces all phandles with value @fdto_phandle by @fdt_phandle.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_update_node_conflicting_references(void *fdto, int tree_node,
int fixup_node,
uint32_t fdt_phandle,
uint32_t fdto_phandle)
{
int fixup_prop;
int fixup_child;
int ret;
fdt_for_each_property_offset(fixup_prop, fdto, fixup_node) {
const fdt32_t *fixup_val;
const char *name;
char *tree_val;
int fixup_len;
int tree_len;
int i;
fixup_val = fdt_getprop_by_offset(fdto, fixup_prop,
&name, &fixup_len);
if (!fixup_val)
return fixup_len;
if (fixup_len % sizeof(uint32_t))
return -FDT_ERR_BADOVERLAY;
fixup_len /= sizeof(uint32_t);
tree_val = fdt_getprop_w(fdto, tree_node, name, &tree_len);
if (!tree_val) {
if (tree_len == -FDT_ERR_NOTFOUND)
return -FDT_ERR_BADOVERLAY;
return tree_len;
}
for (i = 0; i < fixup_len; i++) {
fdt32_t *refp;
uint32_t valp;
refp = (fdt32_t *)(tree_val + fdt32_ld_(fixup_val + i));
valp = fdt32_ld(refp);
if (valp == fdto_phandle)
fdt32_st(refp, fdt_phandle);
}
}
fdt_for_each_subnode(fixup_child, fdto, fixup_node) {
const char *fixup_child_name = fdt_get_name(fdto, fixup_child, NULL);
int tree_child;
tree_child = fdt_subnode_offset(fdto, tree_node, fixup_child_name);
if (tree_child == -FDT_ERR_NOTFOUND)
return -FDT_ERR_BADOVERLAY;
if (tree_child < 0)
return tree_child;
ret = overlay_update_node_conflicting_references(fdto, tree_child,
fixup_child,
fdt_phandle,
fdto_phandle);
if (ret)
return ret;
}
return 0;
}
/**
* overlay_update_local_conflicting_references - Recursively replace phandle values
* @fdto: Device tree overlay blob
* @fdt_phandle: Value to replace phandles with
* @fdto_phandle: Value to be replaced
*
* Replaces all phandles with value @fdto_phandle by @fdt_phandle.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_update_local_conflicting_references(void *fdto,
uint32_t fdt_phandle,
uint32_t fdto_phandle)
{
int fixups;
fixups = fdt_path_offset(fdto, "/__local_fixups__");
if (fixups == -FDT_ERR_NOTFOUND)
return 0;
if (fixups < 0)
return fixups;
return overlay_update_node_conflicting_references(fdto, 0, fixups,
fdt_phandle,
fdto_phandle);
}
/**
* overlay_prevent_phandle_overwrite_node - Helper function for overlay_prevent_phandle_overwrite
* @fdt: Base Device tree blob
* @fdtnode: Node in fdt that is checked for an overwrite
* @fdto: Device tree overlay blob
* @fdtonode: Node in fdto matching @fdtnode
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_prevent_phandle_overwrite_node(void *fdt, int fdtnode,
void *fdto, int fdtonode)
{
uint32_t fdt_phandle, fdto_phandle;
int fdtochild;
fdt_phandle = fdt_get_phandle(fdt, fdtnode);
fdto_phandle = fdt_get_phandle(fdto, fdtonode);
if (fdt_phandle && fdto_phandle) {
int ret;
ret = overlay_adjust_local_conflicting_phandle(fdto, fdtonode,
fdt_phandle);
if (ret)
return ret;
ret = overlay_update_local_conflicting_references(fdto,
fdt_phandle,
fdto_phandle);
if (ret)
return ret;
}
fdt_for_each_subnode(fdtochild, fdto, fdtonode) {
const char *name = fdt_get_name(fdto, fdtochild, NULL);
int fdtchild;
int ret;
fdtchild = fdt_subnode_offset(fdt, fdtnode, name);
if (fdtchild == -FDT_ERR_NOTFOUND)
/*
* no further overwrites possible here as this node is
* new
*/
continue;
ret = overlay_prevent_phandle_overwrite_node(fdt, fdtchild,
fdto, fdtochild);
if (ret)
return ret;
}
return 0;
}
/**
* overlay_prevent_phandle_overwrite - Fixes overlay phandles to not overwrite base phandles
* @fdt: Base Device Tree blob
* @fdto: Device tree overlay blob
*
* Checks recursively if applying fdto overwrites phandle values in the base
* dtb. When such a phandle is found, the fdto is changed to use the fdt's
* phandle value to not break references in the base.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_prevent_phandle_overwrite(void *fdt, void *fdto)
{
int fragment;
fdt_for_each_subnode(fragment, fdto, 0) {
int overlay;
int target;
int ret;
overlay = fdt_subnode_offset(fdto, fragment, "__overlay__");
if (overlay == -FDT_ERR_NOTFOUND)
continue;
if (overlay < 0)
return overlay;
target = fdt_overlay_target_offset(fdt, fdto, fragment, NULL);
if (target == -FDT_ERR_NOTFOUND)
/*
* The subtree doesn't exist in the base, so nothing
* will be overwritten.
*/
continue;
else if (target < 0)
return target;
ret = overlay_prevent_phandle_overwrite_node(fdt, target,
fdto, overlay);
if (ret)
return ret;
}
return 0;
}
/**
* overlay_apply_node - Merges a node into the base device tree
* @fdt: Base Device Tree blob
* @target: Node offset in the base device tree to apply the fragment to
* @fdto: Device tree overlay blob
* @node: Node offset in the overlay holding the changes to merge
*
* overlay_apply_node() merges a node into a target base device tree
* node pointed.
*
* This is part of the final step in the device tree overlay
* application process, when all the phandles have been adjusted and
* resolved and you just have to merge overlay into the base device
* tree.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_apply_node(void *fdt, int target,
void *fdto, int node)
{
int property;
int subnode;
fdt_for_each_property_offset(property, fdto, node) {
const char *name;
const void *prop;
int prop_len;
int ret;
prop = fdt_getprop_by_offset(fdto, property, &name,
&prop_len);
if (prop_len == -FDT_ERR_NOTFOUND)
return -FDT_ERR_INTERNAL;
if (prop_len < 0)
return prop_len;
ret = fdt_setprop(fdt, target, name, prop, prop_len);
if (ret)
return ret;
}
fdt_for_each_subnode(subnode, fdto, node) {
const char *name = fdt_get_name(fdto, subnode, NULL);
int nnode;
int ret;
nnode = fdt_add_subnode(fdt, target, name);
if (nnode == -FDT_ERR_EXISTS) {
nnode = fdt_subnode_offset(fdt, target, name);
if (nnode == -FDT_ERR_NOTFOUND)
return -FDT_ERR_INTERNAL;
}
if (nnode < 0)
return nnode;
ret = overlay_apply_node(fdt, nnode, fdto, subnode);
if (ret)
return ret;
}
return 0;
}
/**
* overlay_merge - Merge an overlay into its base device tree
* @fdt: Base Device Tree blob
* @fdto: Device tree overlay blob
*
* overlay_merge() merges an overlay into its base device tree.
*
* This is the next to last step in the device tree overlay application
* process, when all the phandles have been adjusted and resolved and
* you just have to merge overlay into the base device tree.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_merge(void *fdt, void *fdto)
{
int fragment;
fdt_for_each_subnode(fragment, fdto, 0) {
int overlay;
int target;
int ret;
/*
* Each fragments will have an __overlay__ node. If
* they don't, it's not supposed to be merged
*/
overlay = fdt_subnode_offset(fdto, fragment, "__overlay__");
if (overlay == -FDT_ERR_NOTFOUND)
continue;
if (overlay < 0)
return overlay;
target = fdt_overlay_target_offset(fdt, fdto, fragment, NULL);
if (target < 0)
return target;
ret = overlay_apply_node(fdt, target, fdto, overlay);
if (ret)
return ret;
}
return 0;
}
static int get_path_len(const void *fdt, int nodeoffset)
{
int len = 0, namelen;
const char *name;
FDT_RO_PROBE(fdt);
for (;;) {
name = fdt_get_name(fdt, nodeoffset, &namelen);
if (!name)
return namelen;
/* root? we're done */
if (namelen == 0)
break;
nodeoffset = fdt_parent_offset(fdt, nodeoffset);
if (nodeoffset < 0)
return nodeoffset;
len += namelen + 1;
}
/* in case of root pretend it's "/" */
if (len == 0)
len++;
return len;
}
/**
* overlay_symbol_update - Update the symbols of base tree after a merge
* @fdt: Base Device Tree blob
* @fdto: Device tree overlay blob
*
* overlay_symbol_update() updates the symbols of the base tree with the
* symbols of the applied overlay
*
* This is the last step in the device tree overlay application
* process, allowing the reference of overlay symbols by subsequent
* overlay operations.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_symbol_update(void *fdt, void *fdto)
{
int root_sym, ov_sym, prop, path_len, fragment, target;
int len, frag_name_len, ret, rel_path_len;
const char *s, *e;
const char *path;
const char *name;
const char *frag_name;
const char *rel_path;
const char *target_path;
char *buf;
void *p;
ov_sym = fdt_subnode_offset(fdto, 0, "__symbols__");
/* if no overlay symbols exist no problem */
if (ov_sym < 0)
return 0;
root_sym = fdt_subnode_offset(fdt, 0, "__symbols__");
/* it no root symbols exist we should create them */
if (root_sym == -FDT_ERR_NOTFOUND)
root_sym = fdt_add_subnode(fdt, 0, "__symbols__");
/* any error is fatal now */
if (root_sym < 0)
return root_sym;
/* iterate over each overlay symbol */
fdt_for_each_property_offset(prop, fdto, ov_sym) {
path = fdt_getprop_by_offset(fdto, prop, &name, &path_len);
if (!path)
return path_len;
/* verify it's a string property (terminated by a single \0) */
if (path_len < 1 || memchr(path, '\0', path_len) != &path[path_len - 1])
return -FDT_ERR_BADVALUE;
/* keep end marker to avoid strlen() */
e = path + path_len;
if (*path != '/')
return -FDT_ERR_BADVALUE;
/* get fragment name first */
s = strchr(path + 1, '/');
if (!s) {
/* Symbol refers to something that won't end
* up in the target tree */
continue;
}
frag_name = path + 1;
frag_name_len = s - path - 1;
/* verify format; safe since "s" lies in \0 terminated prop */
len = sizeof("/__overlay__/") - 1;
if ((e - s) > len && (memcmp(s, "/__overlay__/", len) == 0)) {
/* /<fragment-name>/__overlay__/<relative-subnode-path> */
rel_path = s + len;
rel_path_len = e - rel_path - 1;
} else if ((e - s) == len
&& (memcmp(s, "/__overlay__", len - 1) == 0)) {
/* /<fragment-name>/__overlay__ */
rel_path = "";
rel_path_len = 0;
} else {
/* Symbol refers to something that won't end
* up in the target tree */
continue;
}
/* find the fragment index in which the symbol lies */
ret = fdt_subnode_offset_namelen(fdto, 0, frag_name,
frag_name_len);
/* not found? */
if (ret < 0)
return -FDT_ERR_BADOVERLAY;
fragment = ret;
/* an __overlay__ subnode must exist */
ret = fdt_subnode_offset(fdto, fragment, "__overlay__");
if (ret < 0)
return -FDT_ERR_BADOVERLAY;
/* get the target of the fragment */
ret = fdt_overlay_target_offset(fdt, fdto, fragment, &target_path);
if (ret < 0)
return ret;
target = ret;
/* if we have a target path use */
if (!target_path) {
ret = get_path_len(fdt, target);
if (ret < 0)
return ret;
len = ret;
} else {
len = strlen(target_path);
}
ret = fdt_setprop_placeholder(fdt, root_sym, name,
len + (len > 1) + rel_path_len + 1, &p);
if (ret < 0)
return ret;
if (!target_path) {
/* again in case setprop_placeholder changed it */
ret = fdt_overlay_target_offset(fdt, fdto, fragment, &target_path);
if (ret < 0)
return ret;
target = ret;
}
buf = p;
if (len > 1) { /* target is not root */
if (!target_path) {
ret = fdt_get_path(fdt, target, buf, len + 1);
if (ret < 0)
return ret;
} else
memcpy(buf, target_path, len + 1);
} else
len--;
buf[len] = '/';
memcpy(buf + len + 1, rel_path, rel_path_len);
buf[len + 1 + rel_path_len] = '\0';
}
return 0;
}
int fdt_overlay_apply(void *fdt, void *fdto)
{
uint32_t delta;
int ret;
FDT_RO_PROBE(fdt);
FDT_RO_PROBE(fdto);
ret = fdt_find_max_phandle(fdt, &delta);
if (ret)
goto err;
/* Increase all phandles in the fdto by delta */
ret = overlay_adjust_local_phandles(fdto, delta);
if (ret)
goto err;
/* Adapt the phandle values in fdto to the above increase */
ret = overlay_update_local_references(fdto, delta);
if (ret)
goto err;
/* Update fdto's phandles using symbols from fdt */
ret = overlay_fixup_phandles(fdt, fdto);
if (ret)
goto err;
/* Don't overwrite phandles in fdt */
ret = overlay_prevent_phandle_overwrite(fdt, fdto);
if (ret)
goto err;
ret = overlay_merge(fdt, fdto);
if (ret)
goto err;
ret = overlay_symbol_update(fdt, fdto);
if (ret)
goto err;
/*
* The overlay has been damaged, erase its magic.
*/
fdt_set_magic(fdto, ~0);
return 0;
err:
/*
* The overlay might have been damaged, erase its magic.
*/
fdt_set_magic(fdto, ~0);
/*
* The base device tree might have been damaged, erase its
* magic.
*/
fdt_set_magic(fdt, ~0);
return ret;
}
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