/* * Copyright 2013 Google Inc. * Copyright 2018-present Facebook, Inc. * * Taken from depthcharge: src/base/device_tree.c * * This program 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 program 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. */ #include <assert.h> #include <console/console.h> #include <device_tree.h> #include <endian.h> #include <stdint.h> #include <string.h> #include <stddef.h> #include <stdlib.h> /* * Functions for picking apart flattened trees. */ int fdt_next_property(const void *blob, uint32_t offset, struct fdt_property *prop) { struct fdt_header *header = (struct fdt_header *)blob; uint32_t *ptr = (uint32_t *)(((uint8_t *)blob) + offset); int index = 0; if (be32toh(ptr[index++]) != FDT_TOKEN_PROPERTY) return 0; uint32_t size = be32toh(ptr[index++]); uint32_t name_offset = be32toh(ptr[index++]); name_offset += be32toh(header->strings_offset); if (prop) { prop->name = (char *)((uint8_t *)blob + name_offset); prop->data = &ptr[index]; prop->size = size; } index += DIV_ROUND_UP(size, sizeof(uint32_t)); return index * sizeof(uint32_t); } int fdt_node_name(const void *blob, uint32_t offset, const char **name) { uint8_t *ptr = ((uint8_t *)blob) + offset; if (be32toh(*(uint32_t *)ptr) != FDT_TOKEN_BEGIN_NODE) return 0; ptr += 4; if (name) *name = (char *)ptr; return ALIGN_UP(strlen((char *)ptr) + 1, sizeof(uint32_t)) + 4; } /* * Functions for printing flattened trees. */ static void print_indent(int depth) { while (depth--) printk(BIOS_DEBUG, " "); } static void print_property(const struct fdt_property *prop, int depth) { print_indent(depth); printk(BIOS_DEBUG, "prop \"%s\" (%d bytes).\n", prop->name, prop->size); print_indent(depth + 1); for (int i = 0; i < MIN(25, prop->size); i++) { printk(BIOS_DEBUG, "%02x ", ((uint8_t *)prop->data)[i]); } if (prop->size > 25) printk(BIOS_DEBUG, "..."); printk(BIOS_DEBUG, "\n"); } static int print_flat_node(const void *blob, uint32_t start_offset, int depth) { int offset = start_offset; const char *name; int size; size = fdt_node_name(blob, offset, &name); if (!size) return 0; offset += size; print_indent(depth); printk(BIOS_DEBUG, "name = %s\n", name); struct fdt_property prop; while ((size = fdt_next_property(blob, offset, &prop))) { print_property(&prop, depth + 1); offset += size; } while ((size = print_flat_node(blob, offset, depth + 1))) offset += size; return offset - start_offset + sizeof(uint32_t); } void fdt_print_node(const void *blob, uint32_t offset) { print_flat_node(blob, offset, 0); } /* * A utility function to skip past nodes in flattened trees. */ int fdt_skip_node(const void *blob, uint32_t start_offset) { int offset = start_offset; int size; const char *name; size = fdt_node_name(blob, offset, &name); if (!size) return 0; offset += size; while ((size = fdt_next_property(blob, offset, NULL))) offset += size; while ((size = fdt_skip_node(blob, offset))) offset += size; return offset - start_offset + sizeof(uint32_t); } /* * Functions to turn a flattened tree into an unflattened one. */ static struct device_tree_node *alloc_node(void) { struct device_tree_node *buf = malloc(sizeof(struct device_tree_node)); if (!buf) return NULL; memset(buf, 0, sizeof(*buf)); return buf; } static struct device_tree_property *alloc_prop(void) { struct device_tree_property *buf = malloc(sizeof(struct device_tree_property)); if (!buf) return NULL; memset(buf, 0, sizeof(*buf)); return buf; } static int fdt_unflatten_node(const void *blob, uint32_t start_offset, struct device_tree_node **new_node) { struct list_node *last; int offset = start_offset; const char *name; int size; size = fdt_node_name(blob, offset, &name); if (!size) return 0; offset += size; struct device_tree_node *node = alloc_node(); *new_node = node; if (!node) return 0; node->name = name; struct fdt_property fprop; last = &node->properties; while ((size = fdt_next_property(blob, offset, &fprop))) { struct device_tree_property *prop = alloc_prop(); if (!prop) return 0; prop->prop = fprop; list_insert_after(&prop->list_node, last); last = &prop->list_node; offset += size; } struct device_tree_node *child; last = &node->children; while ((size = fdt_unflatten_node(blob, offset, &child))) { list_insert_after(&child->list_node, last); last = &child->list_node; offset += size; } return offset - start_offset + sizeof(uint32_t); } static int fdt_unflatten_map_entry(const void *blob, uint32_t offset, struct device_tree_reserve_map_entry **new) { const uint64_t *ptr = (const uint64_t *)(((uint8_t *)blob) + offset); const uint64_t start = be64toh(ptr[0]); const uint64_t size = be64toh(ptr[1]); if (!size) return 0; struct device_tree_reserve_map_entry *entry = malloc(sizeof(*entry)); if (!entry) return 0; memset(entry, 0, sizeof(*entry)); *new = entry; entry->start = start; entry->size = size; return sizeof(uint64_t) * 2; } struct device_tree *fdt_unflatten(const void *blob) { struct device_tree *tree = malloc(sizeof(*tree)); const struct fdt_header *header = (const struct fdt_header *)blob; if (!tree) return NULL; memset(tree, 0, sizeof(*tree)); tree->header = header; uint32_t struct_offset = be32toh(header->structure_offset); uint32_t strings_offset = be32toh(header->strings_offset); uint32_t reserve_offset = be32toh(header->reserve_map_offset); uint32_t min_offset = 0; min_offset = MIN(struct_offset, strings_offset); min_offset = MIN(min_offset, reserve_offset); // Assume everything up to the first non-header component is part of // the header and needs to be preserved. This will protect us against // new elements being added in the future. tree->header_size = min_offset; struct device_tree_reserve_map_entry *entry; uint32_t offset = reserve_offset; int size; struct list_node *last = &tree->reserve_map; while ((size = fdt_unflatten_map_entry(blob, offset, &entry))) { list_insert_after(&entry->list_node, last); last = &entry->list_node; offset += size; } fdt_unflatten_node(blob, struct_offset, &tree->root); return tree; } /* * Functions to find the size of the device tree if it was flattened. */ static void dt_flat_prop_size(struct device_tree_property *prop, uint32_t *struct_size, uint32_t *strings_size) { // Starting token. *struct_size += sizeof(uint32_t); // Size. *struct_size += sizeof(uint32_t); // Name offset. *struct_size += sizeof(uint32_t); // Property value. *struct_size += ALIGN_UP(prop->prop.size, sizeof(uint32_t)); // Property name. *strings_size += strlen(prop->prop.name) + 1; } static void dt_flat_node_size(struct device_tree_node *node, uint32_t *struct_size, uint32_t *strings_size) { // Starting token. *struct_size += sizeof(uint32_t); // Node name. *struct_size += ALIGN_UP(strlen(node->name) + 1, sizeof(uint32_t)); struct device_tree_property *prop; list_for_each(prop, node->properties, list_node) dt_flat_prop_size(prop, struct_size, strings_size); struct device_tree_node *child; list_for_each(child, node->children, list_node) dt_flat_node_size(child, struct_size, strings_size); // End token. *struct_size += sizeof(uint32_t); } uint32_t dt_flat_size(const struct device_tree *tree) { uint32_t size = tree->header_size; struct device_tree_reserve_map_entry *entry; list_for_each(entry, tree->reserve_map, list_node) size += sizeof(uint64_t) * 2; size += sizeof(uint64_t) * 2; uint32_t struct_size = 0; uint32_t strings_size = 0; dt_flat_node_size(tree->root, &struct_size, &strings_size); size += struct_size; // End token. size += sizeof(uint32_t); size += strings_size; return size; } /* * Functions to flatten a device tree. */ static void dt_flatten_map_entry(struct device_tree_reserve_map_entry *entry, void **map_start) { ((uint64_t *)*map_start)[0] = htobe64(entry->start); ((uint64_t *)*map_start)[1] = htobe64(entry->size); *map_start = ((uint8_t *)*map_start) + sizeof(uint64_t) * 2; } static void dt_flatten_prop(struct device_tree_property *prop, void **struct_start, void *strings_base, void **strings_start) { uint8_t *dstruct = (uint8_t *)*struct_start; uint8_t *dstrings = (uint8_t *)*strings_start; *((uint32_t *)dstruct) = htobe32(FDT_TOKEN_PROPERTY); dstruct += sizeof(uint32_t); *((uint32_t *)dstruct) = htobe32(prop->prop.size); dstruct += sizeof(uint32_t); uint32_t name_offset = (uintptr_t)dstrings - (uintptr_t)strings_base; *((uint32_t *)dstruct) = htobe32(name_offset); dstruct += sizeof(uint32_t); strcpy((char *)dstrings, prop->prop.name); dstrings += strlen(prop->prop.name) + 1; memcpy(dstruct, prop->prop.data, prop->prop.size); dstruct += ALIGN_UP(prop->prop.size, sizeof(uint32_t)); *struct_start = dstruct; *strings_start = dstrings; } static void dt_flatten_node(const struct device_tree_node *node, void **struct_start, void *strings_base, void **strings_start) { uint8_t *dstruct = (uint8_t *)*struct_start; uint8_t *dstrings = (uint8_t *)*strings_start; *((uint32_t *)dstruct) = htobe32(FDT_TOKEN_BEGIN_NODE); dstruct += sizeof(uint32_t); strcpy((char *)dstruct, node->name); dstruct += ALIGN_UP(strlen(node->name) + 1, sizeof(uint32_t)); struct device_tree_property *prop; list_for_each(prop, node->properties, list_node) dt_flatten_prop(prop, (void **)&dstruct, strings_base, (void **)&dstrings); struct device_tree_node *child; list_for_each(child, node->children, list_node) dt_flatten_node(child, (void **)&dstruct, strings_base, (void **)&dstrings); *((uint32_t *)dstruct) = htobe32(FDT_TOKEN_END_NODE); dstruct += sizeof(uint32_t); *struct_start = dstruct; *strings_start = dstrings; } void dt_flatten(const struct device_tree *tree, void *start_dest) { uint8_t *dest = (uint8_t *)start_dest; memcpy(dest, tree->header, tree->header_size); struct fdt_header *header = (struct fdt_header *)dest; dest += tree->header_size; struct device_tree_reserve_map_entry *entry; list_for_each(entry, tree->reserve_map, list_node) dt_flatten_map_entry(entry, (void **)&dest); ((uint64_t *)dest)[0] = ((uint64_t *)dest)[1] = 0; dest += sizeof(uint64_t) * 2; uint32_t struct_size = 0; uint32_t strings_size = 0; dt_flat_node_size(tree->root, &struct_size, &strings_size); uint8_t *struct_start = dest; header->structure_offset = htobe32(dest - (uint8_t *)start_dest); header->structure_size = htobe32(struct_size); dest += struct_size; *((uint32_t *)dest) = htobe32(FDT_TOKEN_END); dest += sizeof(uint32_t); uint8_t *strings_start = dest; header->strings_offset = htobe32(dest - (uint8_t *)start_dest); header->strings_size = htobe32(strings_size); dest += strings_size; dt_flatten_node(tree->root, (void **)&struct_start, strings_start, (void **)&strings_start); header->totalsize = htobe32(dest - (uint8_t *)start_dest); } /* * Functions for printing a non-flattened device tree. */ static void print_node(const struct device_tree_node *node, int depth) { print_indent(depth); printk(BIOS_DEBUG, "name = %s\n", node->name); struct device_tree_property *prop; list_for_each(prop, node->properties, list_node) print_property(&prop->prop, depth + 1); struct device_tree_node *child; list_for_each(child, node->children, list_node) print_node(child, depth + 1); } void dt_print_node(const struct device_tree_node *node) { print_node(node, 0); } /* * Functions for reading and manipulating an unflattened device tree. */ /* * Read #address-cells and #size-cells properties from a node. * * @param node The device tree node to read from. * @param addrcp Pointer to store #address-cells in, skipped if NULL. * @param sizecp Pointer to store #size-cells in, skipped if NULL. */ void dt_read_cell_props(const struct device_tree_node *node, u32 *addrcp, u32 *sizecp) { struct device_tree_property *prop; list_for_each(prop, node->properties, list_node) { if (addrcp && !strcmp("#address-cells", prop->prop.name)) *addrcp = be32toh(*(u32 *)prop->prop.data); if (sizecp && !strcmp("#size-cells", prop->prop.name)) *sizecp = be32toh(*(u32 *)prop->prop.data); } } /* * Find a node from a device tree path, relative to a parent node. * * @param parent The node from which to start the relative path lookup. * @param path An array of path component strings that will be looked * up in order to find the node. Must be terminated with * a NULL pointer. Example: {'firmware', 'coreboot', NULL} * @param addrcp Pointer that will be updated with any #address-cells * value found in the path. May be NULL to ignore. * @param sizecp Pointer that will be updated with any #size-cells * value found in the path. May be NULL to ignore. * @param create 1: Create node(s) if not found. 0: Return NULL instead. * @return The found/created node, or NULL. */ struct device_tree_node *dt_find_node(struct device_tree_node *parent, const char **path, u32 *addrcp, u32 *sizecp, int create) { struct device_tree_node *node, *found = NULL; // Update #address-cells and #size-cells for this level. dt_read_cell_props(parent, addrcp, sizecp); if (!*path) return parent; // Find the next node in the path, if it exists. list_for_each(node, parent->children, list_node) { if (!strcmp(node->name, *path)) { found = node; break; } } // Otherwise create it or return NULL. if (!found) { if (!create) return NULL; found = alloc_node(); if (!found) return NULL; found->name = strdup(*path); if (!found->name) return NULL; list_insert_after(&found->list_node, &parent->children); } return dt_find_node(found, path + 1, addrcp, sizecp, create); } /* * Find a node from a string device tree path, relative to a parent node. * * @param parent The node from which to start the relative path lookup. * @param path A string representing a path in the device tree, with * nodes separated by '/'. Example: "soc/firmware/coreboot" * @param addrcp Pointer that will be updated with any #address-cells * value found in the path. May be NULL to ignore. * @param sizecp Pointer that will be updated with any #size-cells * value found in the path. May be NULL to ignore. * @param create 1: Create node(s) if not found. 0: Return NULL instead. * @return The found/created node, or NULL. * * It is the caller responsibility to provide the correct path string, namely * not starting or ending with a '/', and not having "//" anywhere in it. */ struct device_tree_node *dt_find_node_by_path(struct device_tree_node *parent, const char *path, u32 *addrcp, u32 *sizecp, int create) { char *dup_path = strdup(path); /* Hopefully enough depth for any node. */ const char *path_array[15]; int i; char *next_slash; struct device_tree_node *node = NULL; if (!dup_path) return NULL; next_slash = dup_path; path_array[0] = dup_path; for (i = 1; i < (ARRAY_SIZE(path_array) - 1); i++) { next_slash = strchr(next_slash, '/'); if (!next_slash) break; *next_slash++ = '\0'; path_array[i] = next_slash; } if (!next_slash) { path_array[i] = NULL; node = dt_find_node(parent, path_array, addrcp, sizecp, create); } free(dup_path); return node; } /* * Check if given node is compatible. * * @param node The node which is to be checked for compatible property. * @param compat The compatible string to match. * @return 1 = compatible, 0 = not compatible. */ static int dt_check_compat_match(struct device_tree_node *node, const char *compat) { struct device_tree_property *prop; list_for_each(prop, node->properties, list_node) { if (!strcmp("compatible", prop->prop.name)) { size_t bytes = prop->prop.size; const char *str = prop->prop.data; while (bytes > 0) { if (!strncmp(compat, str, bytes)) return 1; size_t len = strnlen(str, bytes) + 1; if (bytes <= len) break; str += len; bytes -= len; } break; } } return 0; } /* * Find a node from a compatible string, in the subtree of a parent node. * * @param parent The parent node under which to look. * @param compat The compatible string to find. * @return The found node, or NULL. */ struct device_tree_node *dt_find_compat(struct device_tree_node *parent, const char *compat) { // Check if the parent node itself is compatible. if (dt_check_compat_match(parent, compat)) return parent; struct device_tree_node *child; list_for_each(child, parent->children, list_node) { struct device_tree_node *found = dt_find_compat(child, compat); if (found) return found; } return NULL; } /* * Find the next compatible child of a given parent. All children upto the * child passed in by caller are ignored. If child is NULL, it considers all the * children to find the first child which is compatible. * * @param parent The parent node under which to look. * @param child The child node to start search from (exclusive). If NULL * consider all children. * @param compat The compatible string to find. * @return The found node, or NULL. */ struct device_tree_node * dt_find_next_compat_child(struct device_tree_node *parent, struct device_tree_node *child, const char *compat) { struct device_tree_node *next; int ignore = 0; if (child) ignore = 1; list_for_each(next, parent->children, list_node) { if (ignore) { if (child == next) ignore = 0; continue; } if (dt_check_compat_match(next, compat)) return next; } return NULL; } /* * Find a node with matching property value, in the subtree of a parent node. * * @param parent The parent node under which to look. * @param name The property name to look for. * @param data The property value to look for. * @param size The property size. */ struct device_tree_node *dt_find_prop_value(struct device_tree_node *parent, const char *name, void *data, size_t size) { struct device_tree_property *prop; /* Check if parent itself has the required property value. */ list_for_each(prop, parent->properties, list_node) { if (!strcmp(name, prop->prop.name)) { size_t bytes = prop->prop.size; const void *prop_data = prop->prop.data; if (size != bytes) break; if (!memcmp(data, prop_data, size)) return parent; break; } } struct device_tree_node *child; list_for_each(child, parent->children, list_node) { struct device_tree_node *found = dt_find_prop_value(child, name, data, size); if (found) return found; } return NULL; } /** * Find the phandle of a node. * * @param node Pointer to node containing the phandle * @return Zero on error, the phandle on success */ uint32_t dt_get_phandle(const struct device_tree_node *node) { const uint32_t *phandle; size_t len; dt_find_bin_prop(node, "phandle", (const void **)&phandle, &len); if (phandle != NULL && len == sizeof(*phandle)) return be32_to_cpu(*phandle); dt_find_bin_prop(node, "linux,phandle", (const void **)&phandle, &len); if (phandle != NULL && len == sizeof(*phandle)) return be32_to_cpu(*phandle); return 0; } /* * Write an arbitrary sized big-endian integer into a pointer. * * @param dest Pointer to the DT property data buffer to write. * @param src The integer to write (in CPU endianness). * @param length the length of the destination integer in bytes. */ void dt_write_int(u8 *dest, u64 src, size_t length) { while (length--) { dest[length] = (u8)src; src >>= 8; } } /* * Delete a property by name in a given node if it exists. * * @param node The device tree node to operate on. * @param name The name of the property to delete. */ void dt_delete_prop(struct device_tree_node *node, const char *name) { struct device_tree_property *prop; list_for_each(prop, node->properties, list_node) { if (!strcmp(prop->prop.name, name)) { list_remove(&prop->list_node); return; } } } /* * Add an arbitrary property to a node, or update it if it already exists. * * @param node The device tree node to add to. * @param name The name of the new property. * @param data The raw data blob to be stored in the property. * @param size The size of data in bytes. */ void dt_add_bin_prop(struct device_tree_node *node, const char *name, const void *data, size_t size) { struct device_tree_property *prop; list_for_each(prop, node->properties, list_node) { if (!strcmp(prop->prop.name, name)) { prop->prop.data = data; prop->prop.size = size; return; } } prop = alloc_prop(); if (!prop) return; list_insert_after(&prop->list_node, &node->properties); prop->prop.name = name; prop->prop.data = data; prop->prop.size = size; } /* * Find given string property in a node and return its content. * * @param node The device tree node to search. * @param name The name of the property. * @return The found string, or NULL. */ const char *dt_find_string_prop(const struct device_tree_node *node, const char *name) { const void *content; size_t size; dt_find_bin_prop(node, name, &content, &size); return content; } /* * Find given property in a node. * * @param node The device tree node to search. * @param name The name of the property. * @param data Pointer to return raw data blob in the property. * @param size Pointer to return the size of data in bytes. */ void dt_find_bin_prop(const struct device_tree_node *node, const char *name, const void **data, size_t *size) { struct device_tree_property *prop; *data = NULL; *size = 0; list_for_each(prop, node->properties, list_node) { if (!strcmp(prop->prop.name, name)) { *data = prop->prop.data; *size = prop->prop.size; return; } } } /* * Add a string property to a node, or update it if it already exists. * * @param node The device tree node to add to. * @param name The name of the new property. * @param str The zero-terminated string to be stored in the property. */ void dt_add_string_prop(struct device_tree_node *node, const char *name, const char *str) { dt_add_bin_prop(node, name, str, strlen(str) + 1); } /* * Add a 32-bit integer property to a node, or update it if it already exists. * * @param node The device tree node to add to. * @param name The name of the new property. * @param val The integer to be stored in the property. */ void dt_add_u32_prop(struct device_tree_node *node, const char *name, u32 val) { u32 *val_ptr = malloc(sizeof(val)); if (!val_ptr) return; *val_ptr = htobe32(val); dt_add_bin_prop(node, name, val_ptr, sizeof(*val_ptr)); } /* * Add a 64-bit integer property to a node, or update it if it already exists. * * @param node The device tree node to add to. * @param name The name of the new property. * @param val The integer to be stored in the property. */ void dt_add_u64_prop(struct device_tree_node *node, const char *name, u64 val) { u64 *val_ptr = malloc(sizeof(val)); if (!val_ptr) return; *val_ptr = htobe64(val); dt_add_bin_prop(node, name, val_ptr, sizeof(*val_ptr)); } /* * Add a 'reg' address list property to a node, or update it if it exists. * * @param node The device tree node to add to. * @param addrs Array of address values to be stored in the property. * @param sizes Array of corresponding size values to 'addrs'. * @param count Number of values in 'addrs' and 'sizes' (must be equal). * @param addr_cells Value of #address-cells property valid for this node. * @param size_cells Value of #size-cells property valid for this node. */ void dt_add_reg_prop(struct device_tree_node *node, u64 *addrs, u64 *sizes, int count, u32 addr_cells, u32 size_cells) { int i; size_t length = (addr_cells + size_cells) * sizeof(u32) * count; u8 *data = malloc(length); if (!data) return; u8 *cur = data; for (i = 0; i < count; i++) { dt_write_int(cur, addrs[i], addr_cells * sizeof(u32)); cur += addr_cells * sizeof(u32); dt_write_int(cur, sizes[i], size_cells * sizeof(u32)); cur += size_cells * sizeof(u32); } dt_add_bin_prop(node, "reg", data, length); } /* * Fixups to apply to a kernel's device tree before booting it. */ struct list_node device_tree_fixups; int dt_apply_fixups(struct device_tree *tree) { struct device_tree_fixup *fixup; list_for_each(fixup, device_tree_fixups, list_node) { assert(fixup->fixup); if (fixup->fixup(fixup, tree)) return 1; } return 0; } int dt_set_bin_prop_by_path(struct device_tree *tree, const char *path, void *data, size_t data_size, int create) { char *path_copy, *prop_name; struct device_tree_node *dt_node; path_copy = strdup(path); if (!path_copy) { printk(BIOS_ERR, "Failed to allocate a copy of path %s\n", path); return 1; } prop_name = strrchr(path_copy, '/'); if (!prop_name) { free(path_copy); printk(BIOS_ERR, "Path %s does not include '/'\n", path); return 1; } *prop_name++ = '\0'; /* Separate path from the property name. */ dt_node = dt_find_node_by_path(tree->root, path_copy, NULL, NULL, create); if (!dt_node) { printk(BIOS_ERR, "Failed to %s %s in the device tree\n", create ? "create" : "find", path_copy); free(path_copy); return 1; } dt_add_bin_prop(dt_node, prop_name, data, data_size); free(path_copy); return 0; } /* * Prepare the /reserved-memory/ node. * * Technically, this can be called more than one time, to init and/or retrieve * the node. But dt_add_u32_prop() may leak a bit of memory if you do. * * @tree: Device tree to add/retrieve from. * @return: The /reserved-memory/ node (or NULL, if error). */ struct device_tree_node *dt_init_reserved_memory_node(struct device_tree *tree) { struct device_tree_node *reserved; u32 addr = 0, size = 0; reserved = dt_find_node_by_path(tree->root, "reserved-memory", &addr, &size, 1); if (!reserved) return NULL; // Binding doc says this should have the same #{address,size}-cells as // the root. dt_add_u32_prop(reserved, "#address-cells", addr); dt_add_u32_prop(reserved, "#size-cells", size); // Binding doc says this should be empty (i.e., 1:1 mapping from root). dt_add_bin_prop(reserved, "ranges", NULL, 0); return reserved; }