libfdt: Import libfdt source (2 of 2)

This adds the applicable libfdt source files (unmodified) and a README
to explain where the source came from.
diff --git a/libfdt/fdt_sw.c b/libfdt/fdt_sw.c
new file mode 100644
index 0000000..41d4891
--- /dev/null
+++ b/libfdt/fdt_sw.c
@@ -0,0 +1,226 @@
+/*
+ * libfdt - Flat Device Tree manipulation
+ * Copyright (C) 2006 David Gibson, IBM Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser 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
+ */
+#include "libfdt_env.h"
+
+#include <fdt.h>
+#include <libfdt.h>
+
+#include "libfdt_internal.h"
+
+static int check_header_sw(void *fdt)
+{
+	if (fdt_magic(fdt) != SW_MAGIC)
+		return -FDT_ERR_BADMAGIC;
+	return 0;
+}
+
+static void *grab_space(void *fdt, int len)
+{
+	int offset = fdt_size_dt_struct(fdt);
+	int spaceleft;
+
+	spaceleft = fdt_totalsize(fdt) - fdt_off_dt_struct(fdt)
+		- fdt_size_dt_strings(fdt);
+
+	if ((offset + len < offset) || (offset + len > spaceleft))
+		return NULL;
+
+	fdt_set_header(fdt, size_dt_struct, offset + len);
+	return fdt_offset_ptr(fdt, offset, len);
+}
+
+int fdt_create(void *buf, int bufsize)
+{
+	void *fdt = buf;
+
+	if (bufsize < sizeof(struct fdt_header))
+		return -FDT_ERR_NOSPACE;
+
+	memset(buf, 0, bufsize);
+
+	fdt_set_header(fdt, magic, SW_MAGIC);
+	fdt_set_header(fdt, version, FDT_LAST_SUPPORTED_VERSION);
+	fdt_set_header(fdt, last_comp_version, FDT_FIRST_SUPPORTED_VERSION);
+	fdt_set_header(fdt, totalsize, bufsize);
+
+	fdt_set_header(fdt, off_mem_rsvmap, ALIGN(sizeof(struct fdt_header),
+					      sizeof(struct fdt_reserve_entry)));
+	fdt_set_header(fdt, off_dt_struct, fdt_off_mem_rsvmap(fdt));
+	fdt_set_header(fdt, off_dt_strings, bufsize);
+
+	return 0;
+}
+
+int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size)
+{
+	struct fdt_reserve_entry *re;
+	int err = check_header_sw(fdt);
+	int offset;
+
+	if (err)
+		return err;
+	if (fdt_size_dt_struct(fdt))
+		return -FDT_ERR_BADSTATE;
+
+	offset = fdt_off_dt_struct(fdt);
+	if ((offset + sizeof(*re)) > fdt_totalsize(fdt))
+		return -FDT_ERR_NOSPACE;
+
+	re = (struct fdt_reserve_entry *)((void *)fdt + offset);
+	re->address = cpu_to_fdt64(addr);
+	re->size = cpu_to_fdt64(size);
+
+	fdt_set_header(fdt, off_dt_struct, offset + sizeof(*re));
+
+	return 0;
+}
+
+int fdt_finish_reservemap(void *fdt)
+{
+	return fdt_add_reservemap_entry(fdt, 0, 0);
+}
+
+int fdt_begin_node(void *fdt, const char *name)
+{
+	struct fdt_node_header *nh;
+	int err = check_header_sw(fdt);
+	int namelen = strlen(name) + 1;
+
+	if (err)
+		return err;
+
+	nh = grab_space(fdt, sizeof(*nh) + ALIGN(namelen, FDT_TAGSIZE));
+	if (! nh)
+		return -FDT_ERR_NOSPACE;
+
+	nh->tag = cpu_to_fdt32(FDT_BEGIN_NODE);
+	memcpy(nh->name, name, namelen);
+	return 0;
+}
+
+int fdt_end_node(void *fdt)
+{
+	uint32_t *en;
+	int err = check_header_sw(fdt);
+
+	if (err)
+		return err;
+
+	en = grab_space(fdt, FDT_TAGSIZE);
+	if (! en)
+		return -FDT_ERR_NOSPACE;
+
+	*en = cpu_to_fdt32(FDT_END_NODE);
+	return 0;
+}
+
+static int find_add_string(void *fdt, const char *s)
+{
+	char *strtab = (char *)fdt + fdt_totalsize(fdt);
+	const char *p;
+	int strtabsize = fdt_size_dt_strings(fdt);
+	int len = strlen(s) + 1;
+	int struct_top, offset;
+
+	p = _fdt_find_string(strtab - strtabsize, strtabsize, s);
+	if (p)
+		return p - strtab;
+
+	/* Add it */
+	offset = -strtabsize - len;
+	struct_top = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
+	if (fdt_totalsize(fdt) + offset < struct_top)
+		return 0; /* no more room :( */
+
+	memcpy(strtab + offset, s, len);
+	fdt_set_header(fdt, size_dt_strings, strtabsize + len);
+	return offset;
+}
+
+int fdt_property(void *fdt, const char *name, const void *val, int len)
+{
+	struct fdt_property *prop;
+	int err = check_header_sw(fdt);
+	int nameoff;
+
+	if (err)
+		return err;
+
+	nameoff = find_add_string(fdt, name);
+	if (nameoff == 0)
+		return -FDT_ERR_NOSPACE;
+
+	prop = grab_space(fdt, sizeof(*prop) + ALIGN(len, FDT_TAGSIZE));
+	if (! prop)
+		return -FDT_ERR_NOSPACE;
+
+	prop->tag = cpu_to_fdt32(FDT_PROP);
+	prop->nameoff = cpu_to_fdt32(nameoff);
+	prop->len = cpu_to_fdt32(len);
+	memcpy(prop->data, val, len);
+	return 0;
+}
+
+int fdt_finish(void *fdt)
+{
+	int err = check_header_sw(fdt);
+	char *p = (char *)fdt;
+	uint32_t *end;
+	int oldstroffset, newstroffset;
+	uint32_t tag;
+	int offset, nextoffset;
+
+	if (err)
+		return err;
+
+	/* Add terminator */
+	end = grab_space(fdt, sizeof(*end));
+	if (! end)
+		return -FDT_ERR_NOSPACE;
+	*end = cpu_to_fdt32(FDT_END);
+
+	/* Relocate the string table */
+	oldstroffset = fdt_totalsize(fdt) - fdt_size_dt_strings(fdt);
+	newstroffset = fdt_off_dt_struct(fdt) + fdt_size_dt_struct(fdt);
+	memmove(p + newstroffset, p + oldstroffset, fdt_size_dt_strings(fdt));
+	fdt_set_header(fdt, off_dt_strings, newstroffset);
+
+	/* Walk the structure, correcting string offsets */
+	offset = 0;
+	while ((tag = _fdt_next_tag(fdt, offset, &nextoffset)) != FDT_END) {
+		if (tag == FDT_PROP) {
+			struct fdt_property *prop = fdt_offset_ptr(fdt, offset,
+								   sizeof(*prop));
+			int nameoff;
+
+			if (! prop)
+				return -FDT_ERR_BADSTRUCTURE;
+
+			nameoff = fdt32_to_cpu(prop->nameoff);
+			nameoff += fdt_size_dt_strings(fdt);
+			prop->nameoff = cpu_to_fdt32(nameoff);
+		}
+		offset = nextoffset;
+	}
+
+	/* Finally, adjust the header */
+	fdt_set_header(fdt, totalsize, newstroffset + fdt_size_dt_strings(fdt));
+	fdt_set_header(fdt, magic, FDT_MAGIC);
+	return 0;
+}