diff options
Diffstat (limited to 'EmbeddedPkg/Library/FdtLib/fdt_overlay.c')
-rw-r--r-- | EmbeddedPkg/Library/FdtLib/fdt_overlay.c | 2041 |
1 files changed, 1127 insertions, 914 deletions
diff --git a/EmbeddedPkg/Library/FdtLib/fdt_overlay.c b/EmbeddedPkg/Library/FdtLib/fdt_overlay.c index 804852c6c2..0e6b8715e4 100644 --- a/EmbeddedPkg/Library/FdtLib/fdt_overlay.c +++ b/EmbeddedPkg/Library/FdtLib/fdt_overlay.c @@ -1,914 +1,1127 @@ -/* - * libfdt - Flat Device Tree manipulation - * Copyright (C) 2016 Free Electrons - * Copyright (C) 2016 NextThing Co. - * - * libfdt is dual licensed: you can use it either under the terms of - * the GPL, or the BSD license, at your option. - * - * a) This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License as - * published by the Free Software Foundation; either version 2 of the - * License, or (at your option) any later version. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public - * License along with this library; if not, write to the Free - * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, - * MA 02110-1301 USA - * - * Alternatively, - * - * b) Redistribution and use in source and binary forms, with or - * without modification, are permitted provided that the following - * conditions are met: - * - * 1. Redistributions of source code must retain the above - * copyright notice, this list of conditions and the following - * disclaimer. - * 2. Redistributions in binary form must reproduce the above - * copyright notice, this list of conditions and the following - * disclaimer in the documentation and/or other materials - * provided with the distribution. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND - * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, - * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF - * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE - * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR - * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT - * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; - * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN - * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR - * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, - * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - */ -#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); -} - -/** - * overlay_get_target - retrieves the offset of a fragment's target - * @fdt: Base device tree blob - * @fdto: Device tree overlay blob - * @fragment: node offset of the fragment in the overlay - * @pathp: pointer which receives the path of the target (or NULL) - * - * overlay_get_target() retrieves the target offset in the base - * device tree of a fragment, no matter how the actual targetting is - * done (through a phandle or a path) - * - * returns: - * the targetted node offset in the base device tree - * Negative error code on error - */ -static int overlay_get_target(const void *fdt, const void *fdto, - int fragment, 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); - 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, "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) -{ - const fdt32_t *val; - uint32_t adj_val; - int len; - - val = fdt_getprop(fdt, node, name, &len); - if (!val) - return len; - - if (len != sizeof(*val)) - return -FDT_ERR_BADPHANDLE; - - adj_val = fdt32_to_cpu(*val); - if ((adj_val + delta) < adj_val) - return -FDT_ERR_NOPHANDLES; - - adj_val += delta; - if (adj_val == (uint32_t)-1) - return -FDT_ERR_NOPHANDLES; - - return fdt_setprop_inplace_u32(fdt, node, name, adj_val); -} - -/** - * 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 *tree_val; - const char *name; - 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; - - tree_val = fdt_getprop(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 / sizeof(uint32_t)); i++) { - fdt32_t adj_val; - uint32_t poffset; - - poffset = fdt32_to_cpu(fixup_val[i]); - - /* - * phandles to fixup can be unaligned. - * - * Use a memcpy for the architectures that do - * not support unaligned accesses. - */ - memcpy(&adj_val, tree_val + poffset, sizeof(adj_val)); - - adj_val = cpu_to_fdt32(fdt32_to_cpu(adj_val) + delta); - - ret = fdt_setprop_inplace_namelen_partial(fdto, - tree_node, - name, - strlen(name), - poffset, - &adj_val, - sizeof(adj_val)); - if (ret == -FDT_ERR_NOSPACE) - return -FDT_ERR_BADOVERLAY; - - if (ret) - return ret; - } - } - - 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 - * @label: Label of the node referenced by the phandle - * - * 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, const char *label) -{ - const char *symbol_path; - uint32_t phandle; - fdt32_t phandle_prop; - int symbol_off, fixup_off; - int prop_len; - - if (symbols_off < 0) - return symbols_off; - - 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; - - 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)); -}; - -unsigned long strtoul(const char *nptr, char **endptr, int base); - -/** - * 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; - - value = fdt_getprop_by_offset(fdto, property, - &label, &len); - if (!value) { - if (len == -FDT_ERR_NOTFOUND) - return -FDT_ERR_INTERNAL; - - return len; - } - - 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, label); - 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_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 = overlay_get_target(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_CHECK_HEADER(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; - - /* format: /<fragment-name>/__overlay__/<relative-subnode-path> */ - - if (*path != '/') - return -FDT_ERR_BADVALUE; - - /* get fragment name first */ - s = strchr(path + 1, '/'); - if (!s) - return -FDT_ERR_BADOVERLAY; - - 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)) - return -FDT_ERR_BADOVERLAY; - - rel_path = s + len; - rel_path_len = e - rel_path; - - /* 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 = overlay_get_target(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 = overlay_get_target(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 = fdt_get_max_phandle(fdt); - int ret; - - FDT_CHECK_HEADER(fdt); - FDT_CHECK_HEADER(fdto); - - ret = overlay_adjust_local_phandles(fdto, delta); - if (ret) - goto err; - - ret = overlay_update_local_references(fdto, delta); - if (ret) - goto err; - - ret = overlay_fixup_phandles(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; -} +/*
+ * libfdt - Flat Device Tree manipulation
+ * Copyright (C) 2016 Free Electrons
+ * Copyright (C) 2016 NextThing Co.
+ *
+ * libfdt is dual licensed: you can use it either under the terms of
+ * the GPL, or the BSD license, at your option.
+ *
+ * a) This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this library; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ *
+ * Alternatively,
+ *
+ * b) Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer.
+ * 2. Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials
+ * provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#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);
+}
+
+/**
+ * overlay_get_target - retrieves the offset of a fragment's target
+ * @fdt: Base device tree blob
+ * @fdto: Device tree overlay blob
+ * @fragment: node offset of the fragment in the overlay
+ * @pathp: pointer which receives the path of the target (or NULL)
+ *
+ * overlay_get_target() retrieves the target offset in the base
+ * device tree of a fragment, no matter how the actual targetting is
+ * done (through a phandle or a path)
+ *
+ * returns:
+ * the targetted node offset in the base device tree
+ * Negative error code on error
+ */
+static int
+overlay_get_target (
+ const void *fdt,
+ const void *fdto,
+ int fragment,
+ 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);
+ 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, "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
+ )
+{
+ const fdt32_t *val;
+ uint32_t adj_val;
+ int len;
+
+ val = fdt_getprop (fdt, node, name, &len);
+ if (!val) {
+ return len;
+ }
+
+ if (len != sizeof (*val)) {
+ return -FDT_ERR_BADPHANDLE;
+ }
+
+ adj_val = fdt32_to_cpu (*val);
+ if ((adj_val + delta) < adj_val) {
+ return -FDT_ERR_NOPHANDLES;
+ }
+
+ adj_val += delta;
+ if (adj_val == (uint32_t)-1) {
+ return -FDT_ERR_NOPHANDLES;
+ }
+
+ return fdt_setprop_inplace_u32 (fdt, node, name, adj_val);
+}
+
+/**
+ * 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 *tree_val;
+ const char *name;
+ 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;
+ }
+
+ tree_val = fdt_getprop (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 / sizeof (uint32_t)); i++) {
+ fdt32_t adj_val;
+ uint32_t poffset;
+
+ poffset = fdt32_to_cpu (fixup_val[i]);
+
+ /*
+ * phandles to fixup can be unaligned.
+ *
+ * Use a memcpy for the architectures that do
+ * not support unaligned accesses.
+ */
+ memcpy (&adj_val, tree_val + poffset, sizeof (adj_val));
+
+ adj_val = cpu_to_fdt32 (fdt32_to_cpu (adj_val) + delta);
+
+ ret = fdt_setprop_inplace_namelen_partial (
+ fdto,
+ tree_node,
+ name,
+ strlen (name),
+ poffset,
+ &adj_val,
+ sizeof (adj_val)
+ );
+ if (ret == -FDT_ERR_NOSPACE) {
+ return -FDT_ERR_BADOVERLAY;
+ }
+
+ if (ret) {
+ return ret;
+ }
+ }
+ }
+
+ 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
+ * @label: Label of the node referenced by the phandle
+ *
+ * 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,
+ const char *label
+ )
+{
+ const char *symbol_path;
+ uint32_t phandle;
+ fdt32_t phandle_prop;
+ int symbol_off, fixup_off;
+ int prop_len;
+
+ if (symbols_off < 0) {
+ return symbols_off;
+ }
+
+ 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;
+ }
+
+ 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)
+ );
+}
+
+unsigned long
+strtoul (
+ const char *nptr,
+ char **endptr,
+ int base
+ );
+
+/**
+ * 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;
+
+ value = fdt_getprop_by_offset (
+ fdto,
+ property,
+ &label,
+ &len
+ );
+ if (!value) {
+ if (len == -FDT_ERR_NOTFOUND) {
+ return -FDT_ERR_INTERNAL;
+ }
+
+ return len;
+ }
+
+ 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,
+ label
+ );
+ 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_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 = overlay_get_target (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_CHECK_HEADER (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;
+
+ /* format: /<fragment-name>/__overlay__/<relative-subnode-path> */
+
+ if (*path != '/') {
+ return -FDT_ERR_BADVALUE;
+ }
+
+ /* get fragment name first */
+ s = strchr (path + 1, '/');
+ if (!s) {
+ return -FDT_ERR_BADOVERLAY;
+ }
+
+ 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)) {
+ return -FDT_ERR_BADOVERLAY;
+ }
+
+ rel_path = s + len;
+ rel_path_len = e - rel_path;
+
+ /* 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 = overlay_get_target (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 = overlay_get_target (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 = fdt_get_max_phandle (fdt);
+ int ret;
+
+ FDT_CHECK_HEADER (fdt);
+ FDT_CHECK_HEADER (fdto);
+
+ ret = overlay_adjust_local_phandles (fdto, delta);
+ if (ret) {
+ goto err;
+ }
+
+ ret = overlay_update_local_references (fdto, delta);
+ if (ret) {
+ goto err;
+ }
+
+ ret = overlay_fixup_phandles (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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