lib: utils/libfdt: Upgrade to v1.6.1 release

Sync with libfdt v1.6.1 release source codes.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

lib/utils/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)) {
@@ -86,6 +90,10 @@ int fdt_check_header(const void *fdt)
 {
 	size_t hdrsize;
 
+	/* 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)
 		return -FDT_ERR_BADMAGIC;
 	if (!can_assume(LATEST)) {
@@ -134,16 +142,20 @@ int fdt_check_header(const void *fdt)
 
 const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
 {
-	unsigned absoffset = offset + fdt_off_dt_struct(fdt);
+	unsigned int uoffset = offset;
+	unsigned int absoffset = offset + fdt_off_dt_struct(fdt);
+
+	if (offset < 0)
+		return NULL;
 
 	if (!can_assume(VALID_INPUT))
-		if ((absoffset < offset)
+		if ((absoffset < uoffset)
 		    || ((absoffset + len) < absoffset)
 		    || (absoffset + len) > fdt_totalsize(fdt))
 			return NULL;
 
 	if (can_assume(LATEST) || fdt_version(fdt) >= 0x11)
-		if (((offset + len) < offset)
+		if (((uoffset + len) < uoffset)
 		    || ((offset + len) > fdt_size_dt_struct(fdt)))
 			return NULL;
 
@@ -206,10 +218,11 @@ uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
 
 int fdt_check_node_offset_(const void *fdt, int offset)
 {
-	if (can_assume(VALID_INPUT))
+	if (!can_assume(VALID_INPUT)
-		return offset;
+	    && ((offset < 0) || (offset % FDT_TAGSIZE)))
-	if ((offset < 0) || (offset % FDT_TAGSIZE)
+		return -FDT_ERR_BADOFFSET;
-	    || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
+
+	if (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE)
 		return -FDT_ERR_BADOFFSET;
 
 	return offset;
@@ -217,8 +230,11 @@ int fdt_check_node_offset_(const void *fdt, int offset)
 
 int fdt_check_prop_offset_(const void *fdt, int offset)
 {
-	if ((offset < 0) || (offset % FDT_TAGSIZE)
+	if (!can_assume(VALID_INPUT)
-	    || (fdt_next_tag(fdt, offset, &offset) != FDT_PROP))
+	    && ((offset < 0) || (offset % FDT_TAGSIZE)))
+		return -FDT_ERR_BADOFFSET;
+
+	if (fdt_next_tag(fdt, offset, &offset) != FDT_PROP)
 		return -FDT_ERR_BADOFFSET;
 
 	return offset;
@@ -306,9 +322,12 @@ const char *fdt_find_string_(const char *strtab, int tabsize, const char *s)
 
 int fdt_move(const void *fdt, void *buf, int bufsize)
 {
+	if (!can_assume(VALID_INPUT) && bufsize < 0)
+		return -FDT_ERR_NOSPACE;
+
 	FDT_RO_PROBE(fdt);
 
-	if (fdt_totalsize(fdt) > bufsize)
+	if (fdt_totalsize(fdt) > (unsigned int)bufsize)
 		return -FDT_ERR_NOSPACE;
 
 	memmove(buf, fdt, fdt_totalsize(fdt));

lib/utils/libfdt/fdt.h

@@ -7,7 +7,7 @@
  * Copyright 2012 Kim Phillips, Freescale Semiconductor.
  */
 
-#ifndef __ASSEMBLER__
+#ifndef __ASSEMBLY__
 
 struct fdt_header {
 	fdt32_t magic;			 /* magic word FDT_MAGIC */

lib/utils/libfdt/fdt_check.c

@@ -19,9 +19,12 @@ int fdt_check_full(const void *fdt, size_t bufsize)
 	unsigned int depth = 0;
 	const void *prop;
 	const char *propname;
+	bool expect_end = false;
 
 	if (bufsize < FDT_V1_SIZE)
 		return -FDT_ERR_TRUNCATED;
+	if (bufsize < fdt_header_size(fdt))
+		return -FDT_ERR_TRUNCATED;
 	err = fdt_check_header(fdt);
 	if (err != 0)
 		return err;
@@ -39,6 +42,10 @@ int fdt_check_full(const void *fdt, size_t bufsize)
 		if (nextoffset < 0)
 			return nextoffset;
 
+		/* If we see two root nodes, something is wrong */
+		if (expect_end && tag != FDT_END)
+			return -FDT_ERR_BADSTRUCTURE;
+
 		switch (tag) {
 		case FDT_NOP:
 			break;
@@ -52,12 +59,24 @@ int fdt_check_full(const void *fdt, size_t bufsize)
 			depth++;
 			if (depth > INT_MAX)
 				return -FDT_ERR_BADSTRUCTURE;
+
+			/* The root node must have an empty name */
+			if (depth == 1) {
+				const char *name;
+				int len;
+
+				name = fdt_get_name(fdt, offset, &len);
+				if (*name || len)
+					return -FDT_ERR_BADSTRUCTURE;
+			}
 			break;
 
 		case FDT_END_NODE:
 			if (depth == 0)
 				return -FDT_ERR_BADSTRUCTURE;
 			depth--;
+			if (depth == 0)
+				expect_end = true;
 			break;
 
 		case FDT_PROP:

lib/utils/libfdt/fdt_overlay.c

@@ -241,6 +241,7 @@ static int overlay_update_local_node_references(void *fdto,
 
 		if (fixup_len % sizeof(uint32_t))
 			return -FDT_ERR_BADOVERLAY;
+		fixup_len /= sizeof(uint32_t);
 
 		tree_val = fdt_getprop(fdto, tree_node, name, &tree_len);
 		if (!tree_val) {
@@ -250,7 +251,7 @@ static int overlay_update_local_node_references(void *fdto,
 			return tree_len;
 		}
 
-		for (i = 0; i < (fixup_len / sizeof(uint32_t)); i++) {
+		for (i = 0; i < fixup_len; i++) {
 			fdt32_t adj_val;
 			uint32_t poffset;
 

lib/utils/libfdt/fdt_ro.c

@@ -53,7 +53,7 @@ const char *fdt_get_string(const void *fdt, int stroffset, int *lenp)
 
 	err = -FDT_ERR_BADOFFSET;
 	absoffset = stroffset + fdt_off_dt_strings(fdt);
-	if (absoffset >= totalsize)
+	if (absoffset >= (unsigned)totalsize)
 		goto fail;
 	len = totalsize - absoffset;
 
@@ -61,17 +61,19 @@ const char *fdt_get_string(const void *fdt, int stroffset, int *lenp)
 		if (stroffset < 0)
 			goto fail;
 		if (can_assume(LATEST) || fdt_version(fdt) >= 17) {
-			if (stroffset >= fdt_size_dt_strings(fdt))
+			if ((unsigned)stroffset >= fdt_size_dt_strings(fdt))
 				goto fail;
 			if ((fdt_size_dt_strings(fdt) - stroffset) < len)
 				len = fdt_size_dt_strings(fdt) - stroffset;
 		}
 	} else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
-		if ((stroffset >= 0)
+		unsigned int sw_stroffset = -stroffset;
-		    || (stroffset < -fdt_size_dt_strings(fdt)))
+
+		if ((stroffset >= 0) ||
+		    (sw_stroffset > fdt_size_dt_strings(fdt)))
 			goto fail;
-		if ((-stroffset) < len)
+		if (sw_stroffset < len)
-			len = -stroffset;
+			len = sw_stroffset;
 	} else {
 		err = -FDT_ERR_INTERNAL;
 		goto fail;
@@ -157,8 +159,8 @@ int fdt_generate_phandle(const void *fdt, uint32_t *phandle)
 
 static const struct fdt_reserve_entry *fdt_mem_rsv(const void *fdt, int n)
 {
-	int offset = n * sizeof(struct fdt_reserve_entry);
+	unsigned int offset = n * sizeof(struct fdt_reserve_entry);
-	int absoffset = fdt_off_mem_rsvmap(fdt) + offset;
+	unsigned int absoffset = fdt_off_mem_rsvmap(fdt) + offset;
 
 	if (!can_assume(VALID_INPUT)) {
 		if (absoffset < fdt_off_mem_rsvmap(fdt))
@@ -179,8 +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);
+	*address = fdt64_ld_(&re->address);
-	*size = fdt64_ld(&re->size);
+	*size = fdt64_ld_(&re->size);
 	return 0;
 }
 
@@ -190,7 +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;
@@ -368,7 +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;
 }
@@ -406,7 +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;
@@ -459,7 +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;
 }
@@ -477,7 +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)
@@ -486,13 +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;
 }
@@ -517,7 +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,
@@ -680,7 +682,7 @@ int fdt_node_offset_by_phandle(const void *fdt, uint32_t phandle)
 {
 	int offset;
 
-	if ((phandle == 0) || (phandle == -1))
+	if ((phandle == 0) || (phandle == ~0U))
 		return -FDT_ERR_BADPHANDLE;
 
 	FDT_RO_PROBE(fdt);

lib/utils/libfdt/fdt_rw.c

@@ -46,7 +46,7 @@ static int fdt_rw_probe_(void *fdt)
 			return err_; \
 	}
 
-static inline int fdt_data_size_(void *fdt)
+static inline unsigned int fdt_data_size_(void *fdt)
 {
 	return fdt_off_dt_strings(fdt) + fdt_size_dt_strings(fdt);
 }
@@ -54,15 +54,16 @@ static inline int fdt_data_size_(void *fdt)
 static int fdt_splice_(void *fdt, void *splicepoint, int oldlen, int newlen)
 {
 	char *p = splicepoint;
-	char *end = (char *)fdt + fdt_data_size_(fdt);
+	unsigned int dsize = fdt_data_size_(fdt);
+	size_t soff = p - (char *)fdt;
 
-	if (((p + oldlen) < p) || ((p + oldlen) > end))
+	if ((oldlen < 0) || (soff + oldlen < soff) || (soff + oldlen > dsize))
 		return -FDT_ERR_BADOFFSET;
-	if ((p < (char *)fdt) || ((end - oldlen + newlen) < (char *)fdt))
+	if ((p < (char *)fdt) || (dsize + newlen < (unsigned)oldlen))
 		return -FDT_ERR_BADOFFSET;
-	if ((end - oldlen + newlen) > ((char *)fdt + fdt_totalsize(fdt)))
+	if (dsize - oldlen + newlen > fdt_totalsize(fdt))
 		return -FDT_ERR_NOSPACE;
-	memmove(p + newlen, p + oldlen, end - p - oldlen);
+	memmove(p + newlen, p + oldlen, ((char *)fdt + dsize) - (p + oldlen));
 	return 0;
 }
 
@@ -348,7 +349,10 @@ int fdt_add_subnode_namelen(void *fdt, int parentoffset,
 		return offset;
 
 	/* Try to place the new node after the parent's properties */
-	fdt_next_tag(fdt, parentoffset, &nextoffset); /* skip the BEGIN_NODE */
+	tag = fdt_next_tag(fdt, parentoffset, &nextoffset);
+	/* the fdt_subnode_offset_namelen() should ensure this never hits */
+	if (!can_assume(LIBFDT_FLAWLESS) && (tag != FDT_BEGIN_NODE))
+		return -FDT_ERR_INTERNAL;
 	do {
 		offset = nextoffset;
 		tag = fdt_next_tag(fdt, offset, &nextoffset);
@@ -390,7 +394,9 @@ int fdt_del_node(void *fdt, int nodeoffset)
 }
 
 static void fdt_packblocks_(const char *old, char *new,
-			    int mem_rsv_size, int struct_size)
+			    int mem_rsv_size,
+			    int struct_size,
+			    int strings_size)
 {
 	int mem_rsv_off, struct_off, strings_off;
 
@@ -405,8 +411,7 @@ static void fdt_packblocks_(const char *old, char *new,
 	fdt_set_off_dt_struct(new, struct_off);
 	fdt_set_size_dt_struct(new, struct_size);
 
-	memmove(new + strings_off, old + fdt_off_dt_strings(old),
+	memmove(new + strings_off, old + fdt_off_dt_strings(old), strings_size);
-		fdt_size_dt_strings(old));
 	fdt_set_off_dt_strings(new, strings_off);
 	fdt_set_size_dt_strings(new, fdt_size_dt_strings(old));
 }
@@ -427,15 +432,17 @@ 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) |
+	if (can_assume(LIBFDT_ORDER) ||
 	    !fdt_blocks_misordered_(fdt, mem_rsv_size, struct_size)) {
 		/* no further work necessary */
 		err = fdt_move(fdt, buf, bufsize);
@@ -464,7 +471,8 @@ int fdt_open_into(const void *fdt, void *buf, int bufsize)
 			return -FDT_ERR_NOSPACE;
 	}
 
-	fdt_packblocks_(fdt, tmp, mem_rsv_size, struct_size);
+	fdt_packblocks_(fdt, tmp, mem_rsv_size, struct_size,
+			fdt_size_dt_strings(fdt));
 	memmove(buf, tmp, newsize);
 
 	fdt_set_magic(buf, FDT_MAGIC);
@@ -484,7 +492,8 @@ int fdt_pack(void *fdt)
 
 	mem_rsv_size = (fdt_num_mem_rsv(fdt)+1)
 		* sizeof(struct fdt_reserve_entry);
-	fdt_packblocks_(fdt, fdt, mem_rsv_size, fdt_size_dt_struct(fdt));
+	fdt_packblocks_(fdt, fdt, mem_rsv_size, fdt_size_dt_struct(fdt),
+			fdt_size_dt_strings(fdt));
 	fdt_set_totalsize(fdt, fdt_data_size_(fdt));
 
 	return 0;

lib/utils/libfdt/fdt_strerror.c

@@ -40,7 +40,7 @@ static struct fdt_errtabent fdt_errtable[] = {
 	FDT_ERRTABENT(FDT_ERR_NOPHANDLES),
 	FDT_ERRTABENT(FDT_ERR_BADFLAGS),
 };
-#define FDT_ERRTABSIZE	(sizeof(fdt_errtable) / sizeof(fdt_errtable[0]))
+#define FDT_ERRTABSIZE	((int)(sizeof(fdt_errtable) / sizeof(fdt_errtable[0])))
 
 const char *fdt_strerror(int errval)
 {
@@ -48,7 +48,7 @@ const char *fdt_strerror(int errval)
 		return "<valid offset/length>";
 	else if (errval == 0)
 		return "<no error>";
-	else if (errval > -FDT_ERRTABSIZE) {
+	else if (-errval < FDT_ERRTABSIZE) {
 		const char *s = fdt_errtable[-errval].str;
 
 		if (s)

lib/utils/libfdt/fdt_sw.c

@@ -32,7 +32,7 @@ static int fdt_sw_probe_(void *fdt)
 /* 'memrsv' state:	Initial state after fdt_create()
  *
  * Allowed functions:
- *	fdt_add_reservmap_entry()
+ *	fdt_add_reservemap_entry()
  *	fdt_finish_reservemap()		[moves to 'struct' state]
  */
 static int fdt_sw_probe_memrsv_(void *fdt)
@@ -93,8 +93,8 @@ static inline uint32_t sw_flags(void *fdt)
 
 static void *fdt_grab_space_(void *fdt, size_t len)
 {
-	int offset = fdt_size_dt_struct(fdt);
+	unsigned int offset = fdt_size_dt_struct(fdt);
-	int spaceleft;
+	unsigned int spaceleft;
 
 	spaceleft = fdt_totalsize(fdt) - fdt_off_dt_struct(fdt)
 		- fdt_size_dt_strings(fdt);
@@ -108,8 +108,8 @@ static void *fdt_grab_space_(void *fdt, size_t len)
 
 int fdt_create_with_flags(void *buf, int bufsize, uint32_t flags)
 {
-	const size_t hdrsize = FDT_ALIGN(sizeof(struct fdt_header),
+	const int hdrsize = FDT_ALIGN(sizeof(struct fdt_header),
-					 sizeof(struct fdt_reserve_entry));
+				      sizeof(struct fdt_reserve_entry));
 	void *fdt = buf;
 
 	if (bufsize < hdrsize)
@@ -152,6 +152,9 @@ int fdt_resize(void *fdt, void *buf, int bufsize)
 
 	FDT_SW_PROBE(fdt);
 
+	if (bufsize < 0)
+		return -FDT_ERR_NOSPACE;
+
 	headsize = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
 	tailsize = fdt_size_dt_strings(fdt);
 
@@ -159,7 +162,7 @@ int fdt_resize(void *fdt, void *buf, int bufsize)
 	    headsize + tailsize > fdt_totalsize(fdt))
 		return -FDT_ERR_INTERNAL;
 
-	if ((headsize + tailsize) > bufsize)
+	if ((headsize + tailsize) > (unsigned)bufsize)
 		return -FDT_ERR_NOSPACE;
 
 	oldtail = (char *)fdt + fdt_totalsize(fdt) - tailsize;
@@ -247,18 +250,18 @@ int fdt_end_node(void *fdt)
 static int fdt_add_string_(void *fdt, const char *s)
 {
 	char *strtab = (char *)fdt + fdt_totalsize(fdt);
-	int strtabsize = fdt_size_dt_strings(fdt);
+	unsigned int strtabsize = fdt_size_dt_strings(fdt);
-	int len = strlen(s) + 1;
+	unsigned int len = strlen(s) + 1;
-	int struct_top, offset;
+	unsigned int struct_top, offset;
 
-	offset = -strtabsize - len;
+	offset = strtabsize + len;
 	struct_top = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
-	if (fdt_totalsize(fdt) + offset < struct_top)
+	if (fdt_totalsize(fdt) - offset < struct_top)
 		return 0; /* no more room :( */
 
-	memcpy(strtab + offset, s, len);
+	memcpy(strtab - offset, s, len);
 	fdt_set_size_dt_strings(fdt, strtabsize + len);
-	return offset;
+	return -offset;
 }
 
 /* Must only be used to roll back in case of error */
@@ -374,7 +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;

lib/utils/libfdt/fdt_wip.c

@@ -23,7 +23,7 @@ int fdt_setprop_inplace_namelen_partial(void *fdt, int nodeoffset,
 	if (!propval)
 		return proplen;
 
-	if (proplen < (len + idx))
+	if ((unsigned)proplen < (len + idx))
 		return -FDT_ERR_NOSPACE;
 
 	memcpy((char *)propval + idx, val, len);

lib/utils/libfdt/libfdt.h

@@ -9,7 +9,12 @@
 #include <libfdt_env.h>
 #include <fdt.h>
 
+#ifdef __cplusplus
+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 */
@@ -97,7 +102,11 @@
 	/* 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
@@ -118,12 +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:
+ * External helpers to access words from a device tree blob. They're built
- *     These helpers access words from a device tree blob.  They're
+ * to work even with unaligned pointers on platforms (such as ARMv5) that don't
- *     built to work even with unaligned pointers on platforms (ike
+ * like unaligned loads and stores.
- *     ARM) 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;
@@ -180,23 +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
+ * Return: offset of next subnode, or -FDT_ERR_NOTFOUND if there are no more
- * @offset:	Offset of previous subnode
+ *         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);
 
@@ -221,7 +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);	\
@@ -265,17 +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
@@ -400,8 +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:
+ * Return: 0 on success or a negative error-code on failure
- *   0 on success or a negative error-code on failure
  */
 int fdt_generate_phandle(const void *fdt, uint32_t *phandle);
 
@@ -421,9 +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.
  *
@@ -446,6 +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,
@@ -485,6 +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);
@@ -584,9 +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)
+ * @property:	property offset (int, lvalue)
- * @fdt:		FDT blob (const void *)
+ * @fdt:	FDT blob (const void *)
- * @node:		node offset (int)
+ * @node:	node offset (int)
  *
  * This is actually a wrapper around a for loop and would be used like so:
  *
@@ -649,6 +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,
@@ -741,6 +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,
@@ -762,10 +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
+ * If @lenp is non-NULL, the length of the property value is also
- * returned, in the integer pointed to by lenp.
+ * returned, in the integer pointed to by @lenp.
  *
  * returns:
  *	pointer to the property's value
@@ -810,8 +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
+ * Identical to fdt_get_alias(), but only examine the first @namelen
- * characters of name for matching the alias name.
+ * 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,
@@ -824,7 +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
@@ -1000,14 +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:
@@ -1071,7 +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);
 
@@ -1080,7 +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
@@ -1100,7 +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
@@ -1124,7 +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
@@ -1213,6 +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,
@@ -1326,8 +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)
@@ -1399,7 +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.
  *
@@ -1417,7 +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.
@@ -1482,7 +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.
@@ -1687,8 +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)
@@ -1859,8 +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)
@@ -1963,13 +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
+ * 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
+ * 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,
@@ -1988,7 +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
@@ -2069,4 +2115,8 @@ int fdt_overlay_apply(void *fdt, void *fdto);
 
 const char *fdt_strerror(int errval);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* LIBFDT_H */

lib/utils/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)
 
 /**********************************************************************/