lib: Raw import FDT devicetree from depthcharge

Import from https://chromium.googlesource.com/chromiumos/platform/depthcharge
Required for general devicetree patching and FIT support.

Coding style and coreboot integration will be done in a separate commit.

Change-Id: Ida75d4786eae38d84bfc71bf53573dafca8eda40
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/25632
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

1 files changed, 937 insertions, 0 deletions

diff --git a/src/lib/device_tree.c b/src/lib/device_tree.c
new file mode 100644
index 0000000000..5f77870e4d
--- /dev/null
+++ b/src/lib/device_tree.c
@@ -0,0 +1,937 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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 <endian.h>
+#include <libpayload.h>
+#include <stdint.h>
+
+#include "base/device_tree.h"
+
+/*
+ * Functions for picking apart flattened trees.
+ */
+
+static uint32_t size32(uint32_t val)
+{
+	return (val + sizeof(uint32_t) - 1) / sizeof(uint32_t);
+}
+
+int fdt_next_property(void *blob, uint32_t offset, FdtProperty *prop)
+{
+	FdtHeader *header = (FdtHeader *)blob;
+	uint32_t *ptr = (uint32_t *)(((uint8_t *)blob) + offset);
+
+	int index = 0;
+	if (betohl(ptr[index++]) != TokenProperty)
+		return 0;
+
+	uint32_t size = betohl(ptr[index++]);
+	uint32_t name_offset = betohl(ptr[index++]);
+	name_offset += betohl(header->strings_offset);
+
+	if (prop) {
+		prop->name = (char *)((uint8_t *)blob + name_offset);
+		prop->data = &ptr[index];
+		prop->size = size;
+	}
+
+	index += size32(size);
+
+	return index * 4;
+}
+
+int fdt_node_name(void *blob, uint32_t offset, const char **name)
+{
+	uint8_t *ptr = ((uint8_t *)blob) + offset;
+
+	if (betohl(*(uint32_t *)ptr) != TokenBeginNode)
+		return 0;
+
+	ptr += 4;
+	if (name)
+		*name = (char *)ptr;
+	return size32(strlen((char *)ptr) + 1) * sizeof(uint32_t) + 4;
+}
+
+
+
+/*
+ * Functions for printing flattened trees.
+ */
+
+static void print_indent(int depth)
+{
+	while (depth--)
+		printf("  ");
+}
+
+static void print_property(FdtProperty *prop, int depth)
+{
+	print_indent(depth);
+	printf("prop \"%s\" (%d bytes).\n", prop->name, prop->size);
+	print_indent(depth + 1);
+	for (int i = 0; i < MIN(25, prop->size); i++) {
+		printf("%02x ", ((uint8_t *)prop->data)[i]);
+	}
+	if (prop->size > 25)
+		printf("...");
+	printf("\n");
+}
+
+static int print_flat_node(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);
+	printf("name = %s\n", name);
+
+	FdtProperty 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(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(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 DeviceTreeNode node_cache[1000];
+static int node_counter = 0;
+static DeviceTreeProperty prop_cache[5000];
+static int prop_counter = 0;
+
+/*
+ * Libpayload's malloc() has linear allocation complexity and goes completely
+ * mental after a few thousand small requests. This little hack will absorb
+ * the worst of it to avoid increasing boot time for no reason.
+ */
+static DeviceTreeNode *alloc_node(void)
+{
+	if (node_counter >= ARRAY_SIZE(node_cache))
+		return xzalloc(sizeof(DeviceTreeNode));
+	return &node_cache[node_counter++];
+}
+static DeviceTreeProperty *alloc_prop(void)
+{
+	if (prop_counter >= ARRAY_SIZE(prop_cache))
+		return xzalloc(sizeof(DeviceTreeProperty));
+	return &prop_cache[prop_counter++];
+}
+
+static int fdt_unflatten_node(void *blob, uint32_t start_offset,
+			      DeviceTreeNode **new_node)
+{
+	ListNode *last;
+	int offset = start_offset;
+	const char *name;
+	int size;
+
+	size = fdt_node_name(blob, offset, &name);
+	if (!size)
+		return 0;
+	offset += size;
+
+	DeviceTreeNode *node = alloc_node();
+	*new_node = node;
+	node->name = name;
+
+	FdtProperty fprop;
+	last = &node->properties;
+	while ((size = fdt_next_property(blob, offset, &fprop))) {
+		DeviceTreeProperty *prop = alloc_prop();
+		prop->prop = fprop;
+
+		list_insert_after(&prop->list_node, last);
+		last = &prop->list_node;
+
+		offset += size;
+	}
+
+	DeviceTreeNode *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(void *blob, uint32_t offset,
+				   DeviceTreeReserveMapEntry **new_entry)
+{
+	uint64_t *ptr = (uint64_t *)(((uint8_t *)blob) + offset);
+	uint64_t start = betohll(ptr[0]);
+	uint64_t size = betohll(ptr[1]);
+
+	if (!size)
+		return 0;
+
+	DeviceTreeReserveMapEntry *entry = xzalloc(sizeof(*entry));
+	*new_entry = entry;
+	entry->start = start;
+	entry->size = size;
+
+	return sizeof(uint64_t) * 2;
+}
+
+DeviceTree *fdt_unflatten(void *blob)
+{
+	DeviceTree *tree = xzalloc(sizeof(*tree));
+	FdtHeader *header = (FdtHeader *)blob;
+	tree->header = header;
+
+	uint32_t struct_offset = betohl(header->structure_offset);
+	uint32_t strings_offset = betohl(header->strings_offset);
+	uint32_t reserve_offset = betohl(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;
+
+	DeviceTreeReserveMapEntry *entry;
+	uint32_t offset = reserve_offset;
+	int size;
+	ListNode *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 device tree would take if it was flattened.
+ */
+
+static void dt_flat_prop_size(DeviceTreeProperty *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 += size32(prop->prop.size) * sizeof(uint32_t);
+
+	// Property name.
+	*strings_size += strlen(prop->prop.name) + 1;
+}
+
+static void dt_flat_node_size(DeviceTreeNode *node, uint32_t *struct_size,
+			      uint32_t *strings_size)
+{
+	// Starting token.
+	*struct_size += sizeof(uint32_t);
+	// Node name.
+	*struct_size += size32(strlen(node->name) + 1) * sizeof(uint32_t);
+
+	DeviceTreeProperty *prop;
+	list_for_each(prop, node->properties, list_node)
+		dt_flat_prop_size(prop, struct_size, strings_size);
+
+	DeviceTreeNode *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(DeviceTree *tree)
+{
+	uint32_t size = tree->header_size;
+	DeviceTreeReserveMapEntry *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(DeviceTreeReserveMapEntry *entry,
+				 void **map_start)
+{
+	((uint64_t *)*map_start)[0] = htobell(entry->start);
+	((uint64_t *)*map_start)[1] = htobell(entry->size);
+	*map_start = ((uint8_t *)*map_start) + sizeof(uint64_t) * 2;
+}
+
+static void dt_flatten_prop(DeviceTreeProperty *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) = htobel(TokenProperty);
+	dstruct += sizeof(uint32_t);
+
+	*((uint32_t *)dstruct) = htobel(prop->prop.size);
+	dstruct += sizeof(uint32_t);
+
+	uint32_t name_offset = (uintptr_t)dstrings - (uintptr_t)strings_base;
+	*((uint32_t *)dstruct) = htobel(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 += size32(prop->prop.size) * 4;
+
+	*struct_start = dstruct;
+	*strings_start = dstrings;
+}
+
+static void dt_flatten_node(DeviceTreeNode *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) = htobel(TokenBeginNode);
+	dstruct += sizeof(uint32_t);
+
+	strcpy((char *)dstruct, node->name);
+	dstruct += size32(strlen(node->name) + 1) * 4;
+
+	DeviceTreeProperty *prop;
+	list_for_each(prop, node->properties, list_node)
+		dt_flatten_prop(prop, (void **)&dstruct, strings_base,
+				(void **)&dstrings);
+
+	DeviceTreeNode *child;
+	list_for_each(child, node->children, list_node)
+		dt_flatten_node(child, (void **)&dstruct, strings_base,
+				(void **)&dstrings);
+
+	*((uint32_t *)dstruct) = htobel(TokenEndNode);
+	dstruct += sizeof(uint32_t);
+
+	*struct_start = dstruct;
+	*strings_start = dstrings;
+}
+
+void dt_flatten(DeviceTree *tree, void *start_dest)
+{
+	uint8_t *dest = (uint8_t *)start_dest;
+
+	memcpy(dest, tree->header, tree->header_size);
+	FdtHeader *header = (FdtHeader *)dest;
+	dest += tree->header_size;
+
+	DeviceTreeReserveMapEntry *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 = htobel(dest - (uint8_t *)start_dest);
+	header->structure_size = htobel(struct_size);
+	dest += struct_size;
+
+	*((uint32_t *)dest) = htobel(TokenEnd);
+	dest += sizeof(uint32_t);
+
+	uint8_t *strings_start = dest;
+	header->strings_offset = htobel(dest - (uint8_t *)start_dest);
+	header->strings_size = htobel(strings_size);
+	dest += strings_size;
+
+	dt_flatten_node(tree->root, (void **)&struct_start, strings_start,
+			(void **)&strings_start);
+
+	header->totalsize = htobel(dest - (uint8_t *)start_dest);
+}
+
+
+
+/*
+ * Functions for printing a non-flattened device tree.
+ */
+
+static void print_node(DeviceTreeNode *node, int depth)
+{
+	print_indent(depth);
+	printf("name = %s\n", node->name);
+
+	DeviceTreeProperty *prop;
+	list_for_each(prop, node->properties, list_node)
+		print_property(&prop->prop, depth + 1);
+
+	DeviceTreeNode *child;
+	list_for_each(child, node->children, list_node)
+		print_node(child, depth + 1);
+}
+
+void dt_print_node(DeviceTreeNode *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(DeviceTreeNode *node, u32 *addrcp, u32 *sizecp)
+{
+	DeviceTreeProperty *prop;
+	list_for_each(prop, node->properties, list_node) {
+		if (addrcp && !strcmp("#address-cells", prop->prop.name))
+			*addrcp = betohl(*(u32 *)prop->prop.data);
+		if (sizecp && !strcmp("#size-cells", prop->prop.name))
+			*sizecp = betohl(*(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.
+ */
+DeviceTreeNode *dt_find_node(DeviceTreeNode *parent, const char **path,
+			     u32 *addrcp, u32 *sizecp, int create)
+{
+	DeviceTreeNode *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();
+		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.
+ */
+DeviceTreeNode *dt_find_node_by_path(DeviceTreeNode *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;
+	DeviceTreeNode *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(DeviceTreeNode *node, const char *compat)
+{
+	DeviceTreeProperty *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.
+ */
+DeviceTreeNode *dt_find_compat(DeviceTreeNode *parent, const char *compat)
+{
+	// Check if the parent node itself is compatible.
+	if (dt_check_compat_match(parent, compat))
+		return parent;
+
+	DeviceTreeNode *child;
+	list_for_each(child, parent->children, list_node) {
+		DeviceTreeNode *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.
+ */
+DeviceTreeNode *dt_find_next_compat_child(DeviceTreeNode *parent,
+					  DeviceTreeNode *child,
+					  const char *compat)
+{
+	DeviceTreeNode *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.
+ */
+DeviceTreeNode *dt_find_prop_value(DeviceTreeNode *parent, const char *name,
+				   void *data, size_t size)
+{
+	DeviceTreeProperty *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;
+			void *prop_data = prop->prop.data;
+			if (size != bytes)
+				break;
+			if (!memcmp(data, prop_data, size))
+				return parent;
+			break;
+		}
+	}
+
+	DeviceTreeNode *child;
+	list_for_each(child, parent->children, list_node) {
+		DeviceTreeNode *found = dt_find_prop_value(child, name, data,
+							   size);
+		if (found)
+			return found;
+	}
+	return NULL;
+}
+
+/*
+ * 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 endianess).
+ * @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;
+	}
+}
+
+/*
+ * 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(DeviceTreeNode *node, char *name, void *data, size_t size)
+{
+	DeviceTreeProperty *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();
+	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(DeviceTreeNode *node, const char *name)
+{
+	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(DeviceTreeNode *node, const char *name, void **data,
+		      size_t *size)
+{
+	DeviceTreeProperty *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(DeviceTreeNode *node, char *name, 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(DeviceTreeNode *node, char *name, u32 val)
+{
+	u32 *val_ptr = xmalloc(sizeof(val));
+	*val_ptr = htobel(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(DeviceTreeNode *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 = xmalloc(length);
+	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.
+ */
+
+ListNode device_tree_fixups;
+
+int dt_apply_fixups(DeviceTree *tree)
+{
+	DeviceTreeFixup *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(DeviceTree *tree, const char *path,
+			    void *data, size_t data_size, int create)
+{
+	char *path_copy, *prop_name;
+	DeviceTreeNode *dt_node;
+
+	path_copy = strdup(path);
+
+	if (!path_copy) {
+		printf("Failed to allocate a copy of path %s\n", path);
+		return 1;
+	}
+
+	prop_name = strrchr(path_copy, '/');
+	if (!prop_name) {
+		printf("Path %s does not include '/'\n", path);
+		free(path_copy);
+		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) {
+		printf("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);
+
+	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).
+ */
+DeviceTreeNode *dt_init_reserved_memory_node(DeviceTree *tree)
+{
+	DeviceTreeNode *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;
+}