libfdt: migrate fdt_rw.c to a wrapper of scripts/dtc/libfdt/fdt_rw.c

The only difference between scripts/dtc/libfdt/fdt_rw.c and
lib/libfdt/fdt_rw.c is fdt_remove_unused_strings().

It is only used by fdtgrep, so we do not need to compile it for U-Boot
image.  Move it to tools/libfdt/fdw_rw.c so that lib/libfdt/fdt_rw.c
can be a wrapper of scripts/dtc/libfdt/fdt_rw.c.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

4 files changed, 56 insertions, 4 deletions

diff --git a/tools/Makefile b/tools/Makefile
index b7d7d418ee..f8731e79de 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -63,11 +63,11 @@ FIT_SIG_OBJS-$(CONFIG_FIT_SIGNATURE) := common/image-sig.o
 
 # The following files are synced with upstream DTC.
 # Use synced versions from scripts/dtc/libfdt/.
-LIBFDT_SRCS_SYNCED := fdt.c fdt_wip.c fdt_sw.c fdt_strerror.c fdt_empty_tree.c \
-		      fdt_addresses.c fdt_overlay.c
+LIBFDT_SRCS_SYNCED := fdt.c fdt_wip.c fdt_sw.c fdt_rw.c \
+		fdt_strerror.c fdt_empty_tree.c fdt_addresses.c fdt_overlay.c
 # The following files are locally modified for U-Boot (unfotunately).
 # Use U-Boot own versions from lib/libfdt/.
-LIBFDT_SRCS_UNSYNCED := fdt_ro.c fdt_rw.c fdt_region.c
+LIBFDT_SRCS_UNSYNCED := fdt_ro.c fdt_region.c
 
 LIBFDT_OBJS := $(addprefix libfdt/, $(patsubst %.c, %.o, $(LIBFDT_SRCS_SYNCED))) \
 	       $(addprefix lib/libfdt/, $(patsubst %.c, %.o, $(LIBFDT_SRCS_UNSYNCED)))
diff --git a/tools/fdt_host.h b/tools/fdt_host.h
index 134d965713..8d4aa066bb 100644
--- a/tools/fdt_host.h
+++ b/tools/fdt_host.h
@@ -11,6 +11,23 @@
 #include "../include/libfdt.h"
 #include "../include/fdt_support.h"
 
+/**
+ * fdt_remove_unused_strings() - Remove any unused strings from an FDT
+ *
+ * This creates a new device tree in @new with unused strings removed. The
+ * called can then use fdt_pack() to minimise the space consumed.
+ *
+ * @old:	Old device tree blog
+ * @new:	Place to put new device tree blob, which must be as large as
+ *		@old
+ * @return
+ *	0, on success
+ *	-FDT_ERR_BADOFFSET, corrupt device tree
+ *	-FDT_ERR_NOSPACE, out of space, which should not happen unless there
+ *		is something very wrong with the device tree input
+ */
+int fdt_remove_unused_strings(const void *old, void *new);
+
 int fit_check_sign(const void *working_fdt, const void *key);
 
 #endif /* __FDT_HOST_H__ */
diff --git a/tools/fdtgrep.c b/tools/fdtgrep.c
index 5897b6d5f7..7af77b7afe 100644
--- a/tools/fdtgrep.c
+++ b/tools/fdtgrep.c
@@ -16,7 +16,7 @@
 #include <string.h>
 #include <unistd.h>
 
-#include "../include/libfdt.h"
+#include "fdt_host.h"
 #include "libfdt_internal.h"
 
 /* Define DEBUG to get some debugging output on stderr */
diff --git a/tools/libfdt/fdt_rw.c b/tools/libfdt/fdt_rw.c
new file mode 100644
index 0000000000..e475084fae
--- /dev/null
+++ b/tools/libfdt/fdt_rw.c
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier:	GPL-2.0+ BSD-2-Clause */
+#include "fdt_host.h"
+#include "../../scripts/dtc/libfdt/fdt_rw.c"
+
+int fdt_remove_unused_strings(const void *old, void *new)
+{
+	const struct fdt_property *old_prop;
+	struct fdt_property *new_prop;
+	int size = fdt_totalsize(old);
+	int next_offset, offset;
+	const char *str;
+	int ret;
+	int tag = FDT_PROP;
+
+	/* Make a copy and remove the strings */
+	memcpy(new, old, size);
+	fdt_set_size_dt_strings(new, 0);
+
+	/* Add every property name back into the new string table */
+	for (offset = 0; tag != FDT_END; offset = next_offset) {
+		tag = fdt_next_tag(old, offset, &next_offset);
+		if (tag != FDT_PROP)
+			continue;
+		old_prop = fdt_get_property_by_offset(old, offset, NULL);
+		new_prop = (struct fdt_property *)(unsigned long)
+			fdt_get_property_by_offset(new, offset, NULL);
+		str = fdt_string(old, fdt32_to_cpu(old_prop->nameoff));
+		ret = _fdt_find_add_string(new, str);
+		if (ret < 0)
+			return ret;
+		new_prop->nameoff = cpu_to_fdt32(ret);
+	}
+
+	return 0;
+}