21 files changed, 367 insertions, 237 deletions

diff --git a/scripts/Makefile.dtbinst b/scripts/Makefile.dtbinst
index 50d580d77ae9..ba01f5ba2517 100644
--- a/scripts/Makefile.dtbinst
+++ b/scripts/Makefile.dtbinst
@@ -29,6 +29,9 @@ quiet_cmd_dtb_install = INSTALL $@
 $(dst)/%.dtb: $(obj)/%.dtb
 	$(call cmd,dtb_install)
 
+$(dst)/%.dtbo: $(obj)/%.dtbo
+	$(call cmd,dtb_install)
+
 PHONY += $(subdirs)
 $(subdirs):
 	$(Q)$(MAKE) $(dtbinst)=$@ dst=$(patsubst $(obj)/%,$(dst)/%,$@)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 213677a5ed33..b00855b247e0 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -86,7 +86,9 @@ extra-$(CONFIG_OF_ALL_DTBS)	+= $(dtb-)
 
 ifneq ($(CHECK_DTBS),)
 extra-y += $(patsubst %.dtb,%.dt.yaml, $(dtb-y))
+extra-y += $(patsubst %.dtbo,%.dt.yaml, $(dtb-y))
 extra-$(CONFIG_OF_ALL_DTBS) += $(patsubst %.dtb,%.dt.yaml, $(dtb-))
+extra-$(CONFIG_OF_ALL_DTBS) += $(patsubst %.dtbo,%.dt.yaml, $(dtb-))
 endif
 
 # Add subdir path
@@ -327,6 +329,9 @@ cmd_dtc = $(HOSTCC) -E $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ;
 $(obj)/%.dtb: $(src)/%.dts $(DTC) FORCE
 	$(call if_changed_dep,dtc)
 
+$(obj)/%.dtbo: $(src)/%.dts $(DTC) FORCE
+	$(call if_changed_dep,dtc)
+
 DT_CHECKER ?= dt-validate
 DT_BINDING_DIR := Documentation/devicetree/bindings
 # DT_TMP_SCHEMA may be overridden from Documentation/devicetree/bindings/Makefile
diff --git a/scripts/coccinelle/free/put_device.cocci b/scripts/coccinelle/free/put_device.cocci
index 120921366e84..f09f1e79bfa6 100644
--- a/scripts/coccinelle/free/put_device.cocci
+++ b/scripts/coccinelle/free/put_device.cocci
@@ -21,7 +21,6 @@ id = of_find_device_by_node@p1(x)
 if (id == NULL || ...) { ... return ...; }
 ... when != put_device(&id->dev)
     when != platform_device_put(id)
-    when != of_dev_put(id)
     when != if (id) { ... put_device(&id->dev) ... }
     when != e1 = (T)id
     when != e1 = (T)(&id->dev)
diff --git a/scripts/dtc/Makefile b/scripts/dtc/Makefile
index 4852bf44e913..c8c21e0f2531 100644
--- a/scripts/dtc/Makefile
+++ b/scripts/dtc/Makefile
@@ -1,13 +1,19 @@
 # SPDX-License-Identifier: GPL-2.0
 # scripts/dtc makefile
 
-hostprogs-always-$(CONFIG_DTC)		+= dtc
+hostprogs-always-$(CONFIG_DTC)		+= dtc fdtoverlay
 hostprogs-always-$(CHECK_DT_BINDING)	+= dtc
 
 dtc-objs	:= dtc.o flattree.o fstree.o data.o livetree.o treesource.o \
 		   srcpos.o checks.o util.o
 dtc-objs	+= dtc-lexer.lex.o dtc-parser.tab.o
 
+# The upstream project builds libfdt as a separate library.  We are choosing to
+# instead directly link the libfdt object files into fdtoverlay.
+libfdt-objs	:= fdt.o fdt_ro.o fdt_wip.o fdt_sw.o fdt_rw.o fdt_strerror.o fdt_empty_tree.o fdt_addresses.o fdt_overlay.o
+libfdt		= $(addprefix libfdt/,$(libfdt-objs))
+fdtoverlay-objs	:= $(libfdt) fdtoverlay.o util.o
+
 # Source files need to get at the userspace version of libfdt_env.h to compile
 HOST_EXTRACFLAGS += -I $(srctree)/$(src)/libfdt
 
diff --git a/scripts/dtc/data.c b/scripts/dtc/data.c
index 0a43b6de3264..14734233ad8b 100644
--- a/scripts/dtc/data.c
+++ b/scripts/dtc/data.c
@@ -21,10 +21,10 @@ void data_free(struct data d)
 		free(d.val);
 }
 
-struct data data_grow_for(struct data d, int xlen)
+struct data data_grow_for(struct data d, unsigned int xlen)
 {
 	struct data nd;
-	int newsize;
+	unsigned int newsize;
 
 	if (xlen == 0)
 		return d;
@@ -84,7 +84,7 @@ struct data data_copy_file(FILE *f, size_t maxlen)
 	while (!feof(f) && (d.len < maxlen)) {
 		size_t chunksize, ret;
 
-		if (maxlen == -1)
+		if (maxlen == (size_t)-1)
 			chunksize = 4096;
 		else
 			chunksize = maxlen - d.len;
diff --git a/scripts/dtc/dtc.c b/scripts/dtc/dtc.c
index bdb3f5945699..838c5df96c00 100644
--- a/scripts/dtc/dtc.c
+++ b/scripts/dtc/dtc.c
@@ -122,6 +122,8 @@ static const char *guess_type_by_name(const char *fname, const char *fallback)
 		return "dts";
 	if (!strcasecmp(s, ".yaml"))
 		return "yaml";
+	if (!strcasecmp(s, ".dtbo"))
+		return "dtb";
 	if (!strcasecmp(s, ".dtb"))
 		return "dtb";
 	return fallback;
@@ -357,6 +359,8 @@ int main(int argc, char *argv[])
 #endif
 	} else if (streq(outform, "dtb")) {
 		dt_to_blob(outf, dti, outversion);
+	} else if (streq(outform, "dtbo")) {
+		dt_to_blob(outf, dti, outversion);
 	} else if (streq(outform, "asm")) {
 		dt_to_asm(outf, dti, outversion);
 	} else if (streq(outform, "null")) {
diff --git a/scripts/dtc/dtc.h b/scripts/dtc/dtc.h
index a08f4159cd03..d3e82fb8e3db 100644
--- a/scripts/dtc/dtc.h
+++ b/scripts/dtc/dtc.h
@@ -105,13 +105,13 @@ extern const char *markername(enum markertype markertype);
 
 struct  marker {
 	enum markertype type;
-	int offset;
+	unsigned int offset;
 	char *ref;
 	struct marker *next;
 };
 
 struct data {
-	int len;
+	unsigned int len;
 	char *val;
 	struct marker *markers;
 };
@@ -129,7 +129,7 @@ size_t type_marker_length(struct marker *m);
 
 void data_free(struct data d);
 
-struct data data_grow_for(struct data d, int xlen);
+struct data data_grow_for(struct data d, unsigned int xlen);
 
 struct data data_copy_mem(const char *mem, int len);
 struct data data_copy_escape_string(const char *s, int len);
@@ -253,7 +253,7 @@ void append_to_property(struct node *node,
 const char *get_unitname(struct node *node);
 struct property *get_property(struct node *node, const char *propname);
 cell_t propval_cell(struct property *prop);
-cell_t propval_cell_n(struct property *prop, int n);
+cell_t propval_cell_n(struct property *prop, unsigned int n);
 struct property *get_property_by_label(struct node *tree, const char *label,
 				       struct node **node);
 struct marker *get_marker_label(struct node *tree, const char *label,
diff --git a/scripts/dtc/fdtdump.c b/scripts/dtc/fdtdump.c
deleted file mode 100644
index 7d460a50b513..000000000000
--- a/scripts/dtc/fdtdump.c
+++ /dev/null
@@ -1,163 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * fdtdump.c - Contributed by Pantelis Antoniou <pantelis.antoniou AT gmail.com>
- */
-
-#include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <ctype.h>
-
-#include <fdt.h>
-#include <libfdt_env.h>
-
-#include "util.h"
-
-#define ALIGN(x, a)	(((x) + ((a) - 1)) & ~((a) - 1))
-#define PALIGN(p, a)	((void *)(ALIGN((unsigned long)(p), (a))))
-#define GET_CELL(p)	(p += 4, *((const uint32_t *)(p-4)))
-
-static void print_data(const char *data, int len)
-{
-	int i;
-	const char *p = data;
-
-	/* no data, don't print */
-	if (len == 0)
-		return;
-
-	if (util_is_printable_string(data, len)) {
-		printf(" = \"%s\"", (const char *)data);
-	} else if ((len % 4) == 0) {
-		printf(" = <");
-		for (i = 0; i < len; i += 4)
-			printf("0x%08x%s", fdt32_to_cpu(GET_CELL(p)),
-			       i < (len - 4) ? " " : "");
-		printf(">");
-	} else {
-		printf(" = [");
-		for (i = 0; i < len; i++)
-			printf("%02x%s", *p++, i < len - 1 ? " " : "");
-		printf("]");
-	}
-}
-
-static void dump_blob(void *blob)
-{
-	struct fdt_header *bph = blob;
-	uint32_t off_mem_rsvmap = fdt32_to_cpu(bph->off_mem_rsvmap);
-	uint32_t off_dt = fdt32_to_cpu(bph->off_dt_struct);
-	uint32_t off_str = fdt32_to_cpu(bph->off_dt_strings);
-	struct fdt_reserve_entry *p_rsvmap =
-		(struct fdt_reserve_entry *)((char *)blob + off_mem_rsvmap);
-	const char *p_struct = (const char *)blob + off_dt;
-	const char *p_strings = (const char *)blob + off_str;
-	uint32_t version = fdt32_to_cpu(bph->version);
-	uint32_t totalsize = fdt32_to_cpu(bph->totalsize);
-	uint32_t tag;
-	const char *p, *s, *t;
-	int depth, sz, shift;
-	int i;
-	uint64_t addr, size;
-
-	depth = 0;
-	shift = 4;
-
-	printf("/dts-v1/;\n");
-	printf("// magic:\t\t0x%x\n", fdt32_to_cpu(bph->magic));
-	printf("// totalsize:\t\t0x%x (%d)\n", totalsize, totalsize);
-	printf("// off_dt_struct:\t0x%x\n", off_dt);
-	printf("// off_dt_strings:\t0x%x\n", off_str);
-	printf("// off_mem_rsvmap:\t0x%x\n", off_mem_rsvmap);
-	printf("// version:\t\t%d\n", version);
-	printf("// last_comp_version:\t%d\n",
-	       fdt32_to_cpu(bph->last_comp_version));
-	if (version >= 2)
-		printf("// boot_cpuid_phys:\t0x%x\n",
-		       fdt32_to_cpu(bph->boot_cpuid_phys));
-
-	if (version >= 3)
-		printf("// size_dt_strings:\t0x%x\n",
-		       fdt32_to_cpu(bph->size_dt_strings));
-	if (version >= 17)
-		printf("// size_dt_struct:\t0x%x\n",
-		       fdt32_to_cpu(bph->size_dt_struct));
-	printf("\n");
-
-	for (i = 0; ; i++) {
-		addr = fdt64_to_cpu(p_rsvmap[i].address);
-		size = fdt64_to_cpu(p_rsvmap[i].size);
-		if (addr == 0 && size == 0)
-			break;
-
-		printf("/memreserve/ %llx %llx;\n",
-		       (unsigned long long)addr, (unsigned long long)size);
-	}
-
-	p = p_struct;
-	while ((tag = fdt32_to_cpu(GET_CELL(p))) != FDT_END) {
-
-		/* printf("tag: 0x%08x (%d)\n", tag, p - p_struct); */
-
-		if (tag == FDT_BEGIN_NODE) {
-			s = p;
-			p = PALIGN(p + strlen(s) + 1, 4);
-
-			if (*s == '\0')
-				s = "/";
-
-			printf("%*s%s {\n", depth * shift, "", s);
-
-			depth++;
-			continue;
-		}
-
-		if (tag == FDT_END_NODE) {
-			depth--;
-
-			printf("%*s};\n", depth * shift, "");
-			continue;
-		}
-
-		if (tag == FDT_NOP) {
-			printf("%*s// [NOP]\n", depth * shift, "");
-			continue;
-		}
-
-		if (tag != FDT_PROP) {
-			fprintf(stderr, "%*s ** Unknown tag 0x%08x\n", depth * shift, "", tag);
-			break;
-		}
-		sz = fdt32_to_cpu(GET_CELL(p));
-		s = p_strings + fdt32_to_cpu(GET_CELL(p));
-		if (version < 16 && sz >= 8)
-			p = PALIGN(p, 8);
-		t = p;
-
-		p = PALIGN(p + sz, 4);
-
-		printf("%*s%s", depth * shift, "", s);
-		print_data(t, sz);
-		printf(";\n");
-	}
-}
-
-
-int main(int argc, char *argv[])
-{
-	char *buf;
-
-	if (argc < 2) {
-		fprintf(stderr, "supply input filename\n");
-		return 5;
-	}
-
-	buf = utilfdt_read(argv[1]);
-	if (buf)
-		dump_blob(buf);
-	else
-		return 10;
-
-	return 0;
-}
diff --git a/scripts/dtc/fdtoverlay.c b/scripts/dtc/fdtoverlay.c
new file mode 100644
index 000000000000..5350af65679f
--- /dev/null
+++ b/scripts/dtc/fdtoverlay.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2017 Konsulko Group Inc. All rights reserved.
+ *
+ * Author:
+ *	 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ */
+
+#include <assert.h>
+#include <ctype.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+
+#include <libfdt.h>
+
+#include "util.h"
+
+#define BUF_INCREMENT	65536
+
+/* Usage related data. */
+static const char usage_synopsis[] =
+	"apply a number of overlays to a base blob\n"
+	"	fdtoverlay <options> [<overlay.dtbo> [<overlay.dtbo>]]\n"
+	"\n"
+	USAGE_TYPE_MSG;
+static const char usage_short_opts[] = "i:o:v" USAGE_COMMON_SHORT_OPTS;
+static struct option const usage_long_opts[] = {
+	{"input",            required_argument, NULL, 'i'},
+	{"output",	     required_argument, NULL, 'o'},
+	{"verbose",	           no_argument, NULL, 'v'},
+	USAGE_COMMON_LONG_OPTS,
+};
+static const char * const usage_opts_help[] = {
+	"Input base DT blob",
+	"Output DT blob",
+	"Verbose messages",
+	USAGE_COMMON_OPTS_HELP
+};
+
+int verbose = 0;
+
+static void *apply_one(char *base, const char *overlay, size_t *buf_len,
+		       const char *name)
+{
+	char *tmp = NULL;
+	char *tmpo;
+	int ret;
+
+	/*
+	 * We take a copies first, because a a failed apply can trash
+	 * both the base blob and the overlay
+	 */
+	tmpo = xmalloc(fdt_totalsize(overlay));
+
+	do {
+		tmp = xrealloc(tmp, *buf_len);
+		ret = fdt_open_into(base, tmp, *buf_len);
+		if (ret) {
+			fprintf(stderr,
+				"\nFailed to make temporary copy: %s\n",
+				fdt_strerror(ret));
+			goto fail;
+		}
+
+		memcpy(tmpo, overlay, fdt_totalsize(overlay));
+
+		ret = fdt_overlay_apply(tmp, tmpo);
+		if (ret == -FDT_ERR_NOSPACE) {
+			*buf_len += BUF_INCREMENT;
+		}
+	} while (ret == -FDT_ERR_NOSPACE);
+
+	if (ret) {
+		fprintf(stderr, "\nFailed to apply '%s': %s\n",
+			name, fdt_strerror(ret));
+		goto fail;
+	}
+
+	free(base);
+	free(tmpo);
+	return tmp;
+
+fail:
+	free(tmpo);
+	if (tmp)
+		free(tmp);
+
+	return NULL;
+}
+static int do_fdtoverlay(const char *input_filename,
+			 const char *output_filename,
+			 int argc, char *argv[])
+{
+	char *blob = NULL;
+	char **ovblob = NULL;
+	size_t buf_len;
+	int i, ret = -1;
+
+	blob = utilfdt_read(input_filename, &buf_len);
+	if (!blob) {
+		fprintf(stderr, "\nFailed to read '%s'\n", input_filename);
+		goto out_err;
+	}
+	if (fdt_totalsize(blob) > buf_len) {
+		fprintf(stderr,
+ "\nBase blob is incomplete (%lu / %" PRIu32 " bytes read)\n",
+			(unsigned long)buf_len, fdt_totalsize(blob));
+		goto out_err;
+	}
+
+	/* allocate blob pointer array */
+	ovblob = xmalloc(sizeof(*ovblob) * argc);
+	memset(ovblob, 0, sizeof(*ovblob) * argc);
+
+	/* read and keep track of the overlay blobs */
+	for (i = 0; i < argc; i++) {
+		size_t ov_len;
+		ovblob[i] = utilfdt_read(argv[i], &ov_len);
+		if (!ovblob[i]) {
+			fprintf(stderr, "\nFailed to read '%s'\n", argv[i]);
+			goto out_err;
+		}
+		if (fdt_totalsize(ovblob[i]) > ov_len) {
+			fprintf(stderr,
+"\nOverlay '%s' is incomplete (%lu / %" PRIu32 " bytes read)\n",
+				argv[i], (unsigned long)ov_len,
+				fdt_totalsize(ovblob[i]));
+			goto out_err;
+		}
+	}
+
+	buf_len = fdt_totalsize(blob);
+
+	/* apply the overlays in sequence */
+	for (i = 0; i < argc; i++) {
+		blob = apply_one(blob, ovblob[i], &buf_len, argv[i]);
+		if (!blob)
+			goto out_err;
+	}
+
+	fdt_pack(blob);
+	ret = utilfdt_write(output_filename, blob);
+	if (ret)
+		fprintf(stderr, "\nFailed to write '%s'\n",
+			output_filename);
+
+out_err:
+	if (ovblob) {
+		for (i = 0; i < argc; i++) {
+			if (ovblob[i])
+				free(ovblob[i]);
+		}
+		free(ovblob);
+	}
+	free(blob);
+
+	return ret;
+}
+
+int main(int argc, char *argv[])
+{
+	int opt, i;
+	char *input_filename = NULL;
+	char *output_filename = NULL;
+
+	while ((opt = util_getopt_long()) != EOF) {
+		switch (opt) {
+		case_USAGE_COMMON_FLAGS
+
+		case 'i':
+			input_filename = optarg;
+			break;
+		case 'o':
+			output_filename = optarg;
+			break;
+		case 'v':
+			verbose = 1;
+			break;
+		}
+	}
+
+	if (!input_filename)
+		usage("missing input file");
+
+	if (!output_filename)
+		usage("missing output file");
+
+	argv += optind;
+	argc -= optind;
+
+	if (argc <= 0)
+		usage("missing overlay file(s)");
+
+	if (verbose) {
+		printf("input  = %s\n", input_filename);
+		printf("output = %s\n", output_filename);
+		for (i = 0; i < argc; i++)
+			printf("overlay[%d] = %s\n", i, argv[i]);
+	}
+
+	if (do_fdtoverlay(input_filename, output_filename, argc, argv))
+		return 1;
+
+	return 0;
+}
diff --git a/scripts/dtc/flattree.c b/scripts/dtc/flattree.c
index 07f10d2b5d79..4659afbfcbab 100644
--- a/scripts/dtc/flattree.c
+++ b/scripts/dtc/flattree.c
@@ -149,7 +149,7 @@ static void asm_emit_align(void *e, int a)
 static void asm_emit_data(void *e, struct data d)
 {
 	FILE *f = e;
-	int off = 0;
+	unsigned int off = 0;
 	struct marker *m = d.markers;
 
 	for_each_marker_of_type(m, LABEL)
@@ -219,7 +219,7 @@ static struct emitter asm_emitter = {
 
 static int stringtable_insert(struct data *d, const char *str)
 {
-	int i;
+	unsigned int i;
 
 	/* FIXME: do this more efficiently? */
 
@@ -345,7 +345,7 @@ static void make_fdt_header(struct fdt_header *fdt,
 void dt_to_blob(FILE *f, struct dt_info *dti, int version)
 {
 	struct version_info *vi = NULL;
-	int i;
+	unsigned int i;
 	struct data blob       = empty_data;
 	struct data reservebuf = empty_data;
 	struct data dtbuf      = empty_data;
@@ -446,7 +446,7 @@ static void dump_stringtable_asm(FILE *f, struct data strbuf)
 void dt_to_asm(FILE *f, struct dt_info *dti, int version)
 {
 	struct version_info *vi = NULL;
-	int i;
+	unsigned int i;
 	struct data strbuf = empty_data;
 	struct reserve_info *re;
 	const char *symprefix = "dt";
diff --git a/scripts/dtc/libfdt/fdt.c b/scripts/dtc/libfdt/fdt.c
index 6cf2fa03b037..3e893073da05 100644
--- a/scripts/dtc/libfdt/fdt.c
+++ b/scripts/dtc/libfdt/fdt.c
@@ -22,6 +22,10 @@ int32_t fdt_ro_probe_(const void *fdt)
 	if (can_assume(VALID_DTB))
 		return totalsize;
 
+	/* The device tree must be at an 8-byte aligned address */
+	if ((uintptr_t)fdt & 7)
+		return -FDT_ERR_ALIGNMENT;
+
 	if (fdt_magic(fdt) == FDT_MAGIC) {
 		/* Complete tree */
 		if (!can_assume(LATEST)) {
diff --git a/scripts/dtc/libfdt/fdt_ro.c b/scripts/dtc/libfdt/fdt_ro.c
index 91cc6fefe374..17584da25760 100644
--- a/scripts/dtc/libfdt/fdt_ro.c
+++ b/scripts/dtc/libfdt/fdt_ro.c
@@ -181,8 +181,8 @@ int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size)
 	if (!can_assume(VALID_INPUT) && !re)
 		return -FDT_ERR_BADOFFSET;
 
-	*address = fdt64_ld(&re->address);
-	*size = fdt64_ld(&re->size);
+	*address = fdt64_ld_(&re->address);
+	*size = fdt64_ld_(&re->size);
 	return 0;
 }
 
@@ -192,7 +192,7 @@ int fdt_num_mem_rsv(const void *fdt)
 	const struct fdt_reserve_entry *re;
 
 	for (i = 0; (re = fdt_mem_rsv(fdt, i)) != NULL; i++) {
-		if (fdt64_ld(&re->size) == 0)
+		if (fdt64_ld_(&re->size) == 0)
 			return i;
 	}
 	return -FDT_ERR_TRUNCATED;
@@ -370,7 +370,7 @@ static const struct fdt_property *fdt_get_property_by_offset_(const void *fdt,
 	prop = fdt_offset_ptr_(fdt, offset);
 
 	if (lenp)
-		*lenp = fdt32_ld(&prop->len);
+		*lenp = fdt32_ld_(&prop->len);
 
 	return prop;
 }
@@ -408,7 +408,7 @@ static const struct fdt_property *fdt_get_property_namelen_(const void *fdt,
 			offset = -FDT_ERR_INTERNAL;
 			break;
 		}
-		if (fdt_string_eq_(fdt, fdt32_ld(&prop->nameoff),
+		if (fdt_string_eq_(fdt, fdt32_ld_(&prop->nameoff),
 				   name, namelen)) {
 			if (poffset)
 				*poffset = offset;
@@ -461,7 +461,7 @@ const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
 
 	/* Handle realignment */
 	if (!can_assume(LATEST) && fdt_version(fdt) < 0x10 &&
-	    (poffset + sizeof(*prop)) % 8 && fdt32_ld(&prop->len) >= 8)
+	    (poffset + sizeof(*prop)) % 8 && fdt32_ld_(&prop->len) >= 8)
 		return prop->data + 4;
 	return prop->data;
 }
@@ -479,7 +479,7 @@ const void *fdt_getprop_by_offset(const void *fdt, int offset,
 		int namelen;
 
 		if (!can_assume(VALID_INPUT)) {
-			name = fdt_get_string(fdt, fdt32_ld(&prop->nameoff),
+			name = fdt_get_string(fdt, fdt32_ld_(&prop->nameoff),
 					      &namelen);
 			if (!name) {
 				if (lenp)
@@ -488,13 +488,13 @@ const void *fdt_getprop_by_offset(const void *fdt, int offset,
 			}
 			*namep = name;
 		} else {
-			*namep = fdt_string(fdt, fdt32_ld(&prop->nameoff));
+			*namep = fdt_string(fdt, fdt32_ld_(&prop->nameoff));
 		}
 	}
 
 	/* Handle realignment */
 	if (!can_assume(LATEST) && fdt_version(fdt) < 0x10 &&
-	    (offset + sizeof(*prop)) % 8 && fdt32_ld(&prop->len) >= 8)
+	    (offset + sizeof(*prop)) % 8 && fdt32_ld_(&prop->len) >= 8)
 		return prop->data + 4;
 	return prop->data;
 }
@@ -519,7 +519,7 @@ uint32_t fdt_get_phandle(const void *fdt, int nodeoffset)
 			return 0;
 	}
 
-	return fdt32_ld(php);
+	return fdt32_ld_(php);
 }
 
 const char *fdt_get_alias_namelen(const void *fdt,
diff --git a/scripts/dtc/libfdt/fdt_rw.c b/scripts/dtc/libfdt/fdt_rw.c
index 68887b969a45..f13458d165d4 100644
--- a/scripts/dtc/libfdt/fdt_rw.c
+++ b/scripts/dtc/libfdt/fdt_rw.c
@@ -428,12 +428,14 @@ int fdt_open_into(const void *fdt, void *buf, int bufsize)
 
 	if (can_assume(LATEST) || fdt_version(fdt) >= 17) {
 		struct_size = fdt_size_dt_struct(fdt);
-	} else {
+	} else if (fdt_version(fdt) == 16) {
 		struct_size = 0;
 		while (fdt_next_tag(fdt, struct_size, &struct_size) != FDT_END)
 			;
 		if (struct_size < 0)
 			return struct_size;
+	} else {
+		return -FDT_ERR_BADVERSION;
 	}
 
 	if (can_assume(LIBFDT_ORDER) ||
diff --git a/scripts/dtc/libfdt/fdt_sw.c b/scripts/dtc/libfdt/fdt_sw.c
index 68b543c4dfa2..4c569ee7eb0d 100644
--- a/scripts/dtc/libfdt/fdt_sw.c
+++ b/scripts/dtc/libfdt/fdt_sw.c
@@ -377,7 +377,7 @@ int fdt_finish(void *fdt)
 	fdt_set_totalsize(fdt, newstroffset + fdt_size_dt_strings(fdt));
 
 	/* And fix up fields that were keeping intermediate state. */
-	fdt_set_last_comp_version(fdt, FDT_FIRST_SUPPORTED_VERSION);
+	fdt_set_last_comp_version(fdt, FDT_LAST_COMPATIBLE_VERSION);
 	fdt_set_magic(fdt, FDT_MAGIC);
 
 	return 0;
diff --git a/scripts/dtc/libfdt/libfdt.h b/scripts/dtc/libfdt/libfdt.h
index fe49b5d78938..c42807a7663e 100644
--- a/scripts/dtc/libfdt/libfdt.h
+++ b/scripts/dtc/libfdt/libfdt.h
@@ -14,6 +14,7 @@ extern "C" {
 #endif
 
 #define FDT_FIRST_SUPPORTED_VERSION	0x02
+#define FDT_LAST_COMPATIBLE_VERSION 0x10
 #define FDT_LAST_SUPPORTED_VERSION	0x11
 
 /* Error codes: informative error codes */
@@ -101,7 +102,11 @@ extern "C" {
 	/* FDT_ERR_BADFLAGS: The function was passed a flags field that
 	 * contains invalid flags or an invalid combination of flags. */
 
-#define FDT_ERR_MAX		18
+#define FDT_ERR_ALIGNMENT	19
+	/* FDT_ERR_ALIGNMENT: The device tree base address is not 8-byte
+	 * aligned. */
+
+#define FDT_ERR_MAX		19
 
 /* constants */
 #define FDT_MAX_PHANDLE 0xfffffffe
@@ -122,12 +127,10 @@ static inline void *fdt_offset_ptr_w(void *fdt, int offset, int checklen)
 uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset);
 
 /*
- * Alignment helpers:
- *     These helpers access words from a device tree blob.  They're
- *     built to work even with unaligned pointers on platforms (ike
- *     ARM) that don't like unaligned loads and stores
+ * External helpers to access words from a device tree blob. They're built
+ * to work even with unaligned pointers on platforms (such as ARMv5) that don't
+ * like unaligned loads and stores.
  */
-
 static inline uint32_t fdt32_ld(const fdt32_t *p)
 {
 	const uint8_t *bp = (const uint8_t *)p;
@@ -184,23 +187,23 @@ int fdt_next_node(const void *fdt, int offset, int *depth);
 
 /**
  * fdt_first_subnode() - get offset of first direct subnode
- *
  * @fdt:	FDT blob
  * @offset:	Offset of node to check
- * @return offset of first subnode, or -FDT_ERR_NOTFOUND if there is none
+ *
+ * Return: offset of first subnode, or -FDT_ERR_NOTFOUND if there is none
  */
 int fdt_first_subnode(const void *fdt, int offset);
 
 /**
  * fdt_next_subnode() - get offset of next direct subnode
+ * @fdt:	FDT blob
+ * @offset:	Offset of previous subnode
  *
  * After first calling fdt_first_subnode(), call this function repeatedly to
  * get direct subnodes of a parent node.
  *
- * @fdt:	FDT blob
- * @offset:	Offset of previous subnode
- * @return offset of next subnode, or -FDT_ERR_NOTFOUND if there are no more
- * subnodes
+ * Return: offset of next subnode, or -FDT_ERR_NOTFOUND if there are no more
+ *         subnodes
  */
 int fdt_next_subnode(const void *fdt, int offset);
 
@@ -225,7 +228,6 @@ int fdt_next_subnode(const void *fdt, int offset);
  * Note that this is implemented as a macro and @node is used as
  * iterator in the loop. The parent variable be constant or even a
  * literal.
- *
  */
 #define fdt_for_each_subnode(node, fdt, parent)		\
 	for (node = fdt_first_subnode(fdt, parent);	\
@@ -269,17 +271,21 @@ fdt_set_hdr_(size_dt_struct);
 /**
  * fdt_header_size - return the size of the tree's header
  * @fdt: pointer to a flattened device tree
+ *
+ * Return: size of DTB header in bytes
  */
 size_t fdt_header_size(const void *fdt);
 
 /**
- * fdt_header_size_ - internal function which takes a version number
+ * fdt_header_size_ - internal function to get header size from a version number
+ * @version: devicetree version number
+ *
+ * Return: size of DTB header in bytes
  */
 size_t fdt_header_size_(uint32_t version);
 
 /**
  * fdt_check_header - sanity check a device tree header
-
  * @fdt: pointer to data which might be a flattened device tree
  *
  * fdt_check_header() checks that the given buffer contains what
@@ -404,8 +410,7 @@ static inline uint32_t fdt_get_max_phandle(const void *fdt)
  * highest phandle value in the device tree blob) will be returned in the
  * @phandle parameter.
  *
- * Returns:
- *   0 on success or a negative error-code on failure
+ * Return: 0 on success or a negative error-code on failure
  */
 int fdt_generate_phandle(const void *fdt, uint32_t *phandle);
 
@@ -425,9 +430,11 @@ int fdt_num_mem_rsv(const void *fdt);
 /**
  * fdt_get_mem_rsv - retrieve one memory reserve map entry
  * @fdt: pointer to the device tree blob
- * @address, @size: pointers to 64-bit variables
+ * @n: index of reserve map entry
+ * @address: pointer to 64-bit variable to hold the start address
+ * @size: pointer to 64-bit variable to hold the size of the entry
  *
- * On success, *address and *size will contain the address and size of
+ * On success, @address and @size will contain the address and size of
  * the n-th reserve map entry from the device tree blob, in
  * native-endian format.
  *
@@ -450,6 +457,8 @@ int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size);
  * namelen characters of name for matching the subnode name.  This is
  * useful for finding subnodes based on a portion of a larger string,
  * such as a full path.
+ *
+ * Return: offset of the subnode or -FDT_ERR_NOTFOUND if name not found.
  */
 #ifndef SWIG /* Not available in Python */
 int fdt_subnode_offset_namelen(const void *fdt, int parentoffset,
@@ -489,6 +498,8 @@ int fdt_subnode_offset(const void *fdt, int parentoffset, const char *name);
  *
  * Identical to fdt_path_offset(), but only consider the first namelen
  * characters of path as the path name.
+ *
+ * Return: offset of the node or negative libfdt error value otherwise
  */
 #ifndef SWIG /* Not available in Python */
 int fdt_path_offset_namelen(const void *fdt, const char *path, int namelen);
@@ -588,9 +599,9 @@ int fdt_next_property_offset(const void *fdt, int offset);
 /**
  * fdt_for_each_property_offset - iterate over all properties of a node
  *
- * @property_offset:	property offset (int, lvalue)
- * @fdt:		FDT blob (const void *)
- * @node:		node offset (int)
+ * @property:	property offset (int, lvalue)
+ * @fdt:	FDT blob (const void *)
+ * @node:	node offset (int)
  *
  * This is actually a wrapper around a for loop and would be used like so:
  *
@@ -653,6 +664,9 @@ const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
  *
  * Identical to fdt_get_property(), but only examine the first namelen
  * characters of name for matching the property name.
+ *
+ * Return: pointer to the structure representing the property, or NULL
+ *         if not found
  */
 #ifndef SWIG /* Not available in Python */
 const struct fdt_property *fdt_get_property_namelen(const void *fdt,
@@ -745,6 +759,8 @@ const void *fdt_getprop_by_offset(const void *fdt, int offset,
  *
  * Identical to fdt_getprop(), but only examine the first namelen
  * characters of name for matching the property name.
+ *
+ * Return: pointer to the property's value or NULL on error
  */
 #ifndef SWIG /* Not available in Python */
 const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
@@ -766,10 +782,10 @@ static inline void *fdt_getprop_namelen_w(void *fdt, int nodeoffset,
  * @lenp: pointer to an integer variable (will be overwritten) or NULL
  *
  * fdt_getprop() retrieves a pointer to the value of the property
- * named 'name' of the node at offset nodeoffset (this will be a
+ * named @name of the node at offset @nodeoffset (this will be a
  * pointer to within the device blob itself, not a copy of the value).
- * If lenp is non-NULL, the length of the property value is also
- * returned, in the integer pointed to by lenp.
+ * If @lenp is non-NULL, the length of the property value is also
+ * returned, in the integer pointed to by @lenp.
  *
  * returns:
  *	pointer to the property's value
@@ -814,8 +830,11 @@ uint32_t fdt_get_phandle(const void *fdt, int nodeoffset);
  * @name: name of the alias th look up
  * @namelen: number of characters of name to consider
  *
- * Identical to fdt_get_alias(), but only examine the first namelen
- * characters of name for matching the alias name.
+ * Identical to fdt_get_alias(), but only examine the first @namelen
+ * characters of @name for matching the alias name.
+ *
+ * Return: a pointer to the expansion of the alias named @name, if it exists,
+ *	   NULL otherwise
  */
 #ifndef SWIG /* Not available in Python */
 const char *fdt_get_alias_namelen(const void *fdt,
@@ -828,7 +847,7 @@ const char *fdt_get_alias_namelen(const void *fdt,
  * @name: name of the alias th look up
  *
  * fdt_get_alias() retrieves the value of a given alias.  That is, the
- * value of the property named 'name' in the node /aliases.
+ * value of the property named @name in the node /aliases.
  *
  * returns:
  *	a pointer to the expansion of the alias named 'name', if it exists
@@ -1004,14 +1023,13 @@ int fdt_node_offset_by_prop_value(const void *fdt, int startoffset,
 int fdt_node_offset_by_phandle(const void *fdt, uint32_t phandle);
 
 /**
- * fdt_node_check_compatible: check a node's compatible property
+ * fdt_node_check_compatible - check a node's compatible property
  * @fdt: pointer to the device tree blob
  * @nodeoffset: offset of a tree node
  * @compatible: string to match against
  *
- *
  * fdt_node_check_compatible() returns 0 if the given node contains a
- * 'compatible' property with the given string as one of its elements,
+ * @compatible property with the given string as one of its elements,
  * it returns non-zero otherwise, or on error.
  *
  * returns:
@@ -1075,7 +1093,7 @@ int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
  * one or more strings, each terminated by \0, as is found in a device tree
  * "compatible" property.
  *
- * @return: 1 if the string is found in the list, 0 not found, or invalid list
+ * Return: 1 if the string is found in the list, 0 not found, or invalid list
  */
 int fdt_stringlist_contains(const char *strlist, int listlen, const char *str);
 
@@ -1084,7 +1102,8 @@ int fdt_stringlist_contains(const char *strlist, int listlen, const char *str);
  * @fdt: pointer to the device tree blob
  * @nodeoffset: offset of a tree node
  * @property: name of the property containing the string list
- * @return:
+ *
+ * Return:
  *   the number of strings in the given property
  *   -FDT_ERR_BADVALUE if the property value is not NUL-terminated
  *   -FDT_ERR_NOTFOUND if the property does not exist
@@ -1104,7 +1123,7 @@ int fdt_stringlist_count(const void *fdt, int nodeoffset, const char *property);
  * small-valued cell properties, such as #address-cells, when searching for
  * the empty string.
  *
- * @return:
+ * return:
  *   the index of the string in the list of strings
  *   -FDT_ERR_BADVALUE if the property value is not NUL-terminated
  *   -FDT_ERR_NOTFOUND if the property does not exist or does not contain
@@ -1128,7 +1147,7 @@ int fdt_stringlist_search(const void *fdt, int nodeoffset, const char *property,
  * If non-NULL, the length of the string (on success) or a negative error-code
  * (on failure) will be stored in the integer pointer to by lenp.
  *
- * @return:
+ * Return:
  *   A pointer to the string at the given index in the string list or NULL on
  *   failure. On success the length of the string will be stored in the memory
  *   location pointed to by the lenp parameter, if non-NULL. On failure one of
@@ -1217,6 +1236,8 @@ int fdt_size_cells(const void *fdt, int nodeoffset);
  * starting from the given index, and using only the first characters
  * of the name. It is useful when you want to manipulate only one value of
  * an array and you have a string that doesn't end with \0.
+ *
+ * Return: 0 on success, negative libfdt error value otherwise
  */
 #ifndef SWIG /* Not available in Python */
 int fdt_setprop_inplace_namelen_partial(void *fdt, int nodeoffset,
@@ -1330,8 +1351,13 @@ static inline int fdt_setprop_inplace_u64(void *fdt, int nodeoffset,
 
 /**
  * fdt_setprop_inplace_cell - change the value of a single-cell property
+ * @fdt: pointer to the device tree blob
+ * @nodeoffset: offset of the node containing the property
+ * @name: name of the property to change the value of
+ * @val: new value of the 32-bit cell
  *
  * This is an alternative name for fdt_setprop_inplace_u32()
+ * Return: 0 on success, negative libfdt error number otherwise.
  */
 static inline int fdt_setprop_inplace_cell(void *fdt, int nodeoffset,
 					   const char *name, uint32_t val)
@@ -1403,7 +1429,7 @@ int fdt_nop_node(void *fdt, int nodeoffset);
 
 /**
  * fdt_create_with_flags - begin creation of a new fdt
- * @fdt: pointer to memory allocated where fdt will be created
+ * @buf: pointer to memory allocated where fdt will be created
  * @bufsize: size of the memory space at fdt
  * @flags: a valid combination of FDT_CREATE_FLAG_ flags, or 0.
  *
@@ -1421,7 +1447,7 @@ int fdt_create_with_flags(void *buf, int bufsize, uint32_t flags);
 
 /**
  * fdt_create - begin creation of a new fdt
- * @fdt: pointer to memory allocated where fdt will be created
+ * @buf: pointer to memory allocated where fdt will be created
  * @bufsize: size of the memory space at fdt
  *
  * fdt_create() is equivalent to fdt_create_with_flags() with flags=0.
@@ -1486,7 +1512,8 @@ int fdt_pack(void *fdt);
 /**
  * fdt_add_mem_rsv - add one memory reserve map entry
  * @fdt: pointer to the device tree blob
- * @address, @size: 64-bit values (native endian)
+ * @address: 64-bit start address of the reserve map entry
+ * @size: 64-bit size of the reserved region
  *
  * Adds a reserve map entry to the given blob reserving a region at
  * address address of length size.
@@ -1691,8 +1718,14 @@ static inline int fdt_setprop_u64(void *fdt, int nodeoffset, const char *name,
 
 /**
  * fdt_setprop_cell - set a property to a single cell value
+ * @fdt: pointer to the device tree blob
+ * @nodeoffset: offset of the node whose property to change
+ * @name: name of the property to change
+ * @val: 32-bit integer value for the property (native endian)
  *
  * This is an alternative name for fdt_setprop_u32()
+ *
+ * Return: 0 on success, negative libfdt error value otherwise.
  */
 static inline int fdt_setprop_cell(void *fdt, int nodeoffset, const char *name,
 				   uint32_t val)
@@ -1863,8 +1896,14 @@ static inline int fdt_appendprop_u64(void *fdt, int nodeoffset,
 
 /**
  * fdt_appendprop_cell - append a single cell value to 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
+ * @val: 32-bit integer value to append to the property (native endian)
  *
  * This is an alternative name for fdt_appendprop_u32()
+ *
+ * Return: 0 on success, negative libfdt error value otherwise.
  */
 static inline int fdt_appendprop_cell(void *fdt, int nodeoffset,
 				      const char *name, uint32_t val)
@@ -1967,13 +2006,16 @@ int fdt_delprop(void *fdt, int nodeoffset, const char *name);
  * fdt_add_subnode_namelen - creates a new node based on substring
  * @fdt: pointer to the device tree blob
  * @parentoffset: structure block offset of a node
- * @name: name of the subnode to locate
+ * @name: name of the subnode to create
  * @namelen: number of characters of name to consider
  *
- * Identical to fdt_add_subnode(), but use only the first namelen
- * characters of name as the name of the new node.  This is useful for
+ * Identical to fdt_add_subnode(), but use only the first @namelen
+ * characters of @name as the name of the new node.  This is useful for
  * creating subnodes based on a portion of a larger string, such as a
  * full path.
+ *
+ * Return: structure block offset of the created subnode (>=0),
+ *	   negative libfdt error value otherwise
  */
 #ifndef SWIG /* Not available in Python */
 int fdt_add_subnode_namelen(void *fdt, int parentoffset,
@@ -1992,7 +2034,7 @@ int fdt_add_subnode_namelen(void *fdt, int parentoffset,
  *
  * This function will insert data into the blob, and will therefore
  * change the offsets of some existing nodes.
-
+ *
  * returns:
  *	structure block offset of the created nodeequested subnode (>=0), on
  *		success
diff --git a/scripts/dtc/libfdt/libfdt_internal.h b/scripts/dtc/libfdt/libfdt_internal.h
index d4e0bd49c037..16bda1906a7b 100644
--- a/scripts/dtc/libfdt/libfdt_internal.h
+++ b/scripts/dtc/libfdt/libfdt_internal.h
@@ -46,6 +46,25 @@ static inline struct fdt_reserve_entry *fdt_mem_rsv_w_(void *fdt, int n)
 	return (void *)(uintptr_t)fdt_mem_rsv_(fdt, n);
 }
 
+/*
+ * Internal helpers to access tructural elements of the device tree
+ * blob (rather than for exaple reading integers from within property
+ * values).  We assume that we are either given a naturally aligned
+ * address for the platform or if we are not, we are on a platform
+ * where unaligned memory reads will be handled in a graceful manner.
+ * If not the external helpers fdtXX_ld() from libfdt.h can be used
+ * instead.
+ */
+static inline uint32_t fdt32_ld_(const fdt32_t *p)
+{
+	return fdt32_to_cpu(*p);
+}
+
+static inline uint64_t fdt64_ld_(const fdt64_t *p)
+{
+	return fdt64_to_cpu(*p);
+}
+
 #define FDT_SW_MAGIC		(~FDT_MAGIC)
 
 /**********************************************************************/
diff --git a/scripts/dtc/livetree.c b/scripts/dtc/livetree.c
index 032df5878ccc..7eacd0248641 100644
--- a/scripts/dtc/livetree.c
+++ b/scripts/dtc/livetree.c
@@ -438,7 +438,7 @@ cell_t propval_cell(struct property *prop)
 	return fdt32_to_cpu(*((fdt32_t *)prop->val.val));
 }
 
-cell_t propval_cell_n(struct property *prop, int n)
+cell_t propval_cell_n(struct property *prop, unsigned int n)
 {
 	assert(prop->val.len / sizeof(cell_t) >= n);
 	return fdt32_to_cpu(*((fdt32_t *)prop->val.val + n));
diff --git a/scripts/dtc/srcpos.c b/scripts/dtc/srcpos.c
index f5205fb9c1ff..4fdb22a019bd 100644
--- a/scripts/dtc/srcpos.c
+++ b/scripts/dtc/srcpos.c
@@ -20,7 +20,7 @@ struct search_path {
 static struct search_path *search_path_head, **search_path_tail;
 
 /* Detect infinite include recursion. */
-#define MAX_SRCFILE_DEPTH     (100)
+#define MAX_SRCFILE_DEPTH     (200)
 static int srcfile_depth; /* = 0 */
 
 static char *get_dirname(const char *path)
diff --git a/scripts/dtc/update-dtc-source.sh b/scripts/dtc/update-dtc-source.sh
index bc704e2a6a4a..32ff17ffd089 100755
--- a/scripts/dtc/update-dtc-source.sh
+++ b/scripts/dtc/update-dtc-source.sh
@@ -37,6 +37,7 @@ DTC_SOURCE="checks.c data.c dtc.c dtc.h flattree.c fstree.c livetree.c srcpos.c
 LIBFDT_SOURCE="fdt.c fdt.h fdt_addresses.c fdt_empty_tree.c \
 		fdt_overlay.c fdt_ro.c fdt_rw.c fdt_strerror.c fdt_sw.c \
 		fdt_wip.c libfdt.h libfdt_env.h libfdt_internal.h"
+FDTOVERLAY_SOURCE=fdtoverlay.c
 
 get_last_dtc_version() {
 	git log --oneline scripts/dtc/ | grep 'upstream' | head -1 | sed -e 's/^.* \(.*\)/\1/'
@@ -54,7 +55,7 @@ dtc_log=$(git log --oneline ${last_dtc_ver}..)
 
 # Copy the files into the Linux tree
 cd $DTC_LINUX_PATH
-for f in $DTC_SOURCE; do
+for f in $DTC_SOURCE $FDTOVERLAY_SOURCE; do
 	cp ${DTC_UPSTREAM_PATH}/${f} ${f}
 	git add ${f}
 done
diff --git a/scripts/dtc/version_gen.h b/scripts/dtc/version_gen.h
index 054cdd0fdbe8..73a7839603f1 100644
--- a/scripts/dtc/version_gen.h
+++ b/scripts/dtc/version_gen.h
@@ -1 +1 @@
-#define DTC_VERSION "DTC 1.6.0-gcbca977e"
+#define DTC_VERSION "DTC 1.6.0-g183df9e9"
diff --git a/scripts/dtc/yamltree.c b/scripts/dtc/yamltree.c
index 4e93c12dc658..e63d32fe142a 100644
--- a/scripts/dtc/yamltree.c
+++ b/scripts/dtc/yamltree.c
@@ -29,11 +29,11 @@ char *yaml_error_name[] = {
 		    (emitter)->problem, __func__, __LINE__);		\
 })
 
-static void yaml_propval_int(yaml_emitter_t *emitter, struct marker *markers, char *data, int len, int width)
+static void yaml_propval_int(yaml_emitter_t *emitter, struct marker *markers, char *data, unsigned int len, int width)
 {
 	yaml_event_t event;
 	void *tag;
-	int off, start_offset = markers->offset;
+	unsigned int off, start_offset = markers->offset;
 
 	switch(width) {
 		case 1: tag = "!u8"; break;
@@ -112,7 +112,7 @@ static void yaml_propval_string(yaml_emitter_t *emitter, char *str, int len)
 static void yaml_propval(yaml_emitter_t *emitter, struct property *prop)
 {
 	yaml_event_t event;
-	int len = prop->val.len;
+	unsigned int len = prop->val.len;
 	struct marker *m = prop->val.markers;
 
 	/* Emit the property name */