Merge tag 'devicetree-for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux

Pull DeviceTree updates from Rob Herring:
 "A bigger diffstat than usual with the kbuild changes and a tree wide
  fix in the binding documentation.

  Summary:

   - kbuild cleanups and improvements for dtbs

   - Code clean-up of overlay code and fixing for some long standing
     memory leak and race condition in applying overlays

   - Improvements to DT memory usage making sysfs/kobjects optional and
     skipping unflattening of disabled nodes. This is part of kernel
     tinification efforts.

   - Final piece of removing storing the full path for every DT node.
     The prerequisite conversion of printk's to use device_node format
     specifier happened in 4.14.

   - Sync with current upstream dtc. This brings additional checks to
     dtb compiling.

   - Binding doc tree wide removal of leading 0s from examples

   - RTC binding documentation adding missing devices and some
     consolidation of duplicated bindings

   - Vendor prefix documentation for nutsboard, Silicon Storage
     Technology, shimafuji, Tecon Microprocessor Technologies, DH
     electronics GmbH, Opal Kelly, and Next Thing"

* tag 'devicetree-for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (55 commits)
  dt-bindings: usb: add #phy-cells to usb-nop-xceiv
  dt-bindings: Remove leading zeros from bindings notation
  kbuild: handle dtb-y and CONFIG_OF_ALL_DTBS natively in Makefile.lib
  MIPS: dts: remove bogus bcm96358nb4ser.dtb from dtb-y entry
  kbuild: clean up *.dtb and *.dtb.S patterns from top-level Makefile
  .gitignore: move *.dtb and *.dtb.S patterns to the top-level .gitignore
  .gitignore: sort normal pattern rules alphabetically
  dt-bindings: add vendor prefix for Next Thing Co.
  scripts/dtc: Update to upstream version v1.4.5-6-gc1e55a5513e9
  of: dynamic: fix memory leak related to properties of __of_node_dup
  of: overlay: make pr_err() string unique
  of: overlay: pr_err from return NOTIFY_OK to overlay apply/remove
  of: overlay: remove unneeded check for NULL kbasename()
  of: overlay: remove a dependency on device node full_name
  of: overlay: simplify applying symbols from an overlay
  of: overlay: avoid race condition between applying multiple overlays
  of: overlay: loosen overly strict phandle clash check
  of: overlay: expand check of whether overlay changeset can be removed
  of: overlay: detect cases where device tree may become corrupt
  of: overlay: minor restructuring
  ...

8 files changed, 1041 insertions, 12 deletions

diff --git a/scripts/dtc/libfdt/fdt_addresses.c b/scripts/dtc/libfdt/fdt_addresses.c
new file mode 100644
index 000000000000..eff4dbcc729d
--- /dev/null
+++ b/scripts/dtc/libfdt/fdt_addresses.c
@@ -0,0 +1,96 @@
+/*
+ * libfdt - Flat Device Tree manipulation
+ * Copyright (C) 2014 David Gibson <david@gibson.dropbear.id.au>
+ *
+ * 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"
+
+int fdt_address_cells(const void *fdt, int nodeoffset)
+{
+	const fdt32_t *ac;
+	int val;
+	int len;
+
+	ac = fdt_getprop(fdt, nodeoffset, "#address-cells", &len);
+	if (!ac)
+		return 2;
+
+	if (len != sizeof(*ac))
+		return -FDT_ERR_BADNCELLS;
+
+	val = fdt32_to_cpu(*ac);
+	if ((val <= 0) || (val > FDT_MAX_NCELLS))
+		return -FDT_ERR_BADNCELLS;
+
+	return val;
+}
+
+int fdt_size_cells(const void *fdt, int nodeoffset)
+{
+	const fdt32_t *sc;
+	int val;
+	int len;
+
+	sc = fdt_getprop(fdt, nodeoffset, "#size-cells", &len);
+	if (!sc)
+		return 2;
+
+	if (len != sizeof(*sc))
+		return -FDT_ERR_BADNCELLS;
+
+	val = fdt32_to_cpu(*sc);
+	if ((val < 0) || (val > FDT_MAX_NCELLS))
+		return -FDT_ERR_BADNCELLS;
+
+	return val;
+}
diff --git a/scripts/dtc/libfdt/fdt_empty_tree.c b/scripts/dtc/libfdt/fdt_empty_tree.c
index f72d13b1d19c..f2ae9b77c285 100644
--- a/scripts/dtc/libfdt/fdt_empty_tree.c
+++ b/scripts/dtc/libfdt/fdt_empty_tree.c
@@ -81,4 +81,3 @@ int fdt_create_empty_tree(void *buf, int bufsize)
 
 	return fdt_open_into(buf, buf, bufsize);
 }
-
diff --git a/scripts/dtc/libfdt/fdt_overlay.c b/scripts/dtc/libfdt/fdt_overlay.c
new file mode 100644
index 000000000000..bd81241e6658
--- /dev/null
+++ b/scripts/dtc/libfdt/fdt_overlay.c
@@ -0,0 +1,861 @@
+#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));
+};
+
+/**
+ * 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;
+}
diff --git a/scripts/dtc/libfdt/fdt_ro.c b/scripts/dtc/libfdt/fdt_ro.c
index 3d00d2eee0e3..08de2cce674d 100644
--- a/scripts/dtc/libfdt/fdt_ro.c
+++ b/scripts/dtc/libfdt/fdt_ro.c
@@ -60,7 +60,7 @@ static int _fdt_nodename_eq(const void *fdt, int offset,
 {
 	const char *p = fdt_offset_ptr(fdt, offset + FDT_TAGSIZE, len+1);
 
-	if (! p)
+	if (!p)
 		/* short match */
 		return 0;
 
@@ -327,7 +327,7 @@ const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
 	const struct fdt_property *prop;
 
 	prop = fdt_get_property_namelen(fdt, nodeoffset, name, namelen, lenp);
-	if (! prop)
+	if (!prop)
 		return NULL;
 
 	return prop->data;
diff --git a/scripts/dtc/libfdt/fdt_rw.c b/scripts/dtc/libfdt/fdt_rw.c
index 3fd5847377c9..5c3a2bb0bc6b 100644
--- a/scripts/dtc/libfdt/fdt_rw.c
+++ b/scripts/dtc/libfdt/fdt_rw.c
@@ -207,7 +207,7 @@ static int _fdt_resize_property(void *fdt, int nodeoffset, const char *name,
 	int err;
 
 	*prop = fdt_get_property_w(fdt, nodeoffset, name, &oldlen);
-	if (! (*prop))
+	if (!*prop)
 		return oldlen;
 
 	if ((err = _fdt_splice_struct(fdt, (*prop)->data, FDT_TAGALIGN(oldlen),
@@ -269,8 +269,8 @@ int fdt_set_name(void *fdt, int nodeoffset, const char *name)
 	return 0;
 }
 
-int fdt_setprop(void *fdt, int nodeoffset, const char *name,
-		const void *val, int len)
+int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
+			    int len, void **prop_data)
 {
 	struct fdt_property *prop;
 	int err;
@@ -283,8 +283,22 @@ int fdt_setprop(void *fdt, int nodeoffset, const char *name,
 	if (err)
 		return err;
 
+	*prop_data = prop->data;
+	return 0;
+}
+
+int fdt_setprop(void *fdt, int nodeoffset, const char *name,
+		const void *val, int len)
+{
+	void *prop_data;
+	int err;
+
+	err = fdt_setprop_placeholder(fdt, nodeoffset, name, len, &prop_data);
+	if (err)
+		return err;
+
 	if (len)
-		memcpy(prop->data, val, len);
+		memcpy(prop_data, val, len);
 	return 0;
 }
 
@@ -323,7 +337,7 @@ int fdt_delprop(void *fdt, int nodeoffset, const char *name)
 	FDT_RW_CHECK_HEADER(fdt);
 
 	prop = fdt_get_property_w(fdt, nodeoffset, name, &len);
-	if (! prop)
+	if (!prop)
 		return len;
 
 	proplen = sizeof(*prop) + FDT_TAGALIGN(len);
diff --git a/scripts/dtc/libfdt/fdt_sw.c b/scripts/dtc/libfdt/fdt_sw.c
index 6a804859fd0c..2bd15e7aef87 100644
--- a/scripts/dtc/libfdt/fdt_sw.c
+++ b/scripts/dtc/libfdt/fdt_sw.c
@@ -220,7 +220,7 @@ static int _fdt_find_add_string(void *fdt, const char *s)
 	return offset;
 }
 
-int fdt_property(void *fdt, const char *name, const void *val, int len)
+int fdt_property_placeholder(void *fdt, const char *name, int len, void **valp)
 {
 	struct fdt_property *prop;
 	int nameoff;
@@ -238,7 +238,19 @@ int fdt_property(void *fdt, const char *name, const void *val, int len)
 	prop->tag = cpu_to_fdt32(FDT_PROP);
 	prop->nameoff = cpu_to_fdt32(nameoff);
 	prop->len = cpu_to_fdt32(len);
-	memcpy(prop->data, val, len);
+	*valp = prop->data;
+	return 0;
+}
+
+int fdt_property(void *fdt, const char *name, const void *val, int len)
+{
+	void *ptr;
+	int ret;
+
+	ret = fdt_property_placeholder(fdt, name, len, &ptr);
+	if (ret)
+		return ret;
+	memcpy(ptr, val, len);
 	return 0;
 }
 
diff --git a/scripts/dtc/libfdt/fdt_wip.c b/scripts/dtc/libfdt/fdt_wip.c
index 6aaab399929c..5e859198622b 100644
--- a/scripts/dtc/libfdt/fdt_wip.c
+++ b/scripts/dtc/libfdt/fdt_wip.c
@@ -82,7 +82,7 @@ int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,
 	int proplen;
 
 	propval = fdt_getprop(fdt, nodeoffset, name, &proplen);
-	if (! propval)
+	if (!propval)
 		return proplen;
 
 	if (proplen != len)
@@ -107,7 +107,7 @@ int fdt_nop_property(void *fdt, int nodeoffset, const char *name)
 	int len;
 
 	prop = fdt_get_property_w(fdt, nodeoffset, name, &len);
-	if (! prop)
+	if (!prop)
 		return len;
 
 	_fdt_nop_region(prop, len + sizeof(*prop));
diff --git a/scripts/dtc/libfdt/libfdt.h b/scripts/dtc/libfdt/libfdt.h
index ba86caa73d01..7f83023ee109 100644
--- a/scripts/dtc/libfdt/libfdt.h
+++ b/scripts/dtc/libfdt/libfdt.h
@@ -1314,6 +1314,22 @@ static inline int fdt_property_cell(void *fdt, const char *name, uint32_t val)
 {
 	return fdt_property_u32(fdt, name, val);
 }
+
+/**
+ * fdt_property_placeholder - add a new property and return a ptr to its value
+ *
+ * @fdt: pointer to the device tree blob
+ * @name: name of property to add
+ * @len: length of property value in bytes
+ * @valp: returns a pointer to where where the value should be placed
+ *
+ * returns:
+ *	0, on success
+ *	-FDT_ERR_BADMAGIC,
+ *	-FDT_ERR_NOSPACE, standard meanings
+ */
+int fdt_property_placeholder(void *fdt, const char *name, int len, void **valp);
+
 #define fdt_property_string(fdt, name, str) \
 	fdt_property(fdt, name, str, strlen(str)+1)
 int fdt_end_node(void *fdt);
@@ -1433,6 +1449,37 @@ int fdt_setprop(void *fdt, int nodeoffset, const char *name,
 		const void *val, int len);
 
 /**
+ * fdt_setprop _placeholder - allocate space for a property
+ * @fdt: pointer to the device tree blob
+ * @nodeoffset: offset of the node whose property to change
+ * @name: name of the property to change
+ * @len: length of the property value
+ * @prop_data: return pointer to property data
+ *
+ * fdt_setprop_placeholer() allocates the named property in the given node.
+ * If the property exists it is resized. In either case a pointer to the
+ * property data is returned.
+ *
+ * This function may insert or delete data from the blob, and will
+ * therefore change the offsets of some existing nodes.
+ *
+ * returns:
+ *	0, on success
+ *	-FDT_ERR_NOSPACE, there is insufficient free space in the blob to
+ *		contain the new property value
+ *	-FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
+ *	-FDT_ERR_BADLAYOUT,
+ *	-FDT_ERR_BADMAGIC,
+ *	-FDT_ERR_BADVERSION,
+ *	-FDT_ERR_BADSTATE,
+ *	-FDT_ERR_BADSTRUCTURE,
+ *	-FDT_ERR_BADLAYOUT,
+ *	-FDT_ERR_TRUNCATED, standard meanings
+ */
+int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
+			    int len, void **prop_data);
+
+/**
  * fdt_setprop_u32 - set a property to a 32-bit integer
  * @fdt: pointer to the device tree blob
  * @nodeoffset: offset of the node whose property to change