|  | // 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); | 
|  | } | 
|  |  | 
|  | /** | 
|  | * 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 targeting is | 
|  | * done (through a phandle or a path) | 
|  | * | 
|  | * returns: | 
|  | *      the targeted 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; | 
|  | fixup_len /= sizeof(uint32_t); | 
|  |  | 
|  | 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; 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)); | 
|  | }; | 
|  |  | 
|  | /** | 
|  | * 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_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 = 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; | 
|  | int ret; | 
|  |  | 
|  | FDT_RO_PROBE(fdt); | 
|  | FDT_RO_PROBE(fdto); | 
|  |  | 
|  | ret = fdt_find_max_phandle(fdt, &delta); | 
|  | if (ret) | 
|  | goto err; | 
|  |  | 
|  | 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; | 
|  | } |