For better or worse libfdt recent grew a lot of code that checks the
validity of the device tree in great detail. When using unsigned or
unverified data this makes things safer, but it does add to code size.

Add some controls to select the trade-off between safety and code size.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>

Thomas reported U-Boot failed to build host tools if libfdt-devel
package is installed because tools include libfdt headers from
/usr/include/ instead of using internal ones.

This commit moves the header code:
  include/libfdt.h         -> include/linux/libfdt.h
  include/libfdt_env.h     -> include/linux/libfdt_env.h

and replaces include directives:
  #include <libfdt.h>      -> #include <linux/libfdt.h>
  #include <libfdt_env.h>  -> #include <linux/libfdt_env.h>

Reported-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

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>

Now, lib/libfdt/fdt_wip.c is the same as scripts/dtc/libfdt/fdt_wip.c

Change the former to a wrapper of the latter.

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

lib/libfdt/ and scripts/dtc/libfdt have the same copies for the
followings 6 files:
  fdt.c fdt_addresses.c fdt_empty_tree.c fdt_overlay.c fdt_strerr.c
  fdt_sw.c

Make them a wrapper of scripts/dtc/libfdt/*.  This is exactly what
Linux does to sync libfdt.  In order to make is possible, import
<linux/libfdt.h> and <linux/libfdt_env.h> from Linux 4.14-rc5.

Unfortunately, U-Boot locally modified the following 3 files:
  fdt_ro.c fdt_wip.c fdt_rw.c

The fdt_region.c is U-Boot own file.

I did not touch them in order to avoid unpredictable impact.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

The device tree overlays are a good way to deal with user-modifyable
boards or boards with some kind of an expansion mechanism where we can
easily plug new board in (like the BBB, the Raspberry Pi or the CHIP).

Add a new function to merge overlays with a base device tree.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

A number of style fixes across the files in this directory, including:

 * Correct invalid kernel-doc content.
 * Tidy up massive comment in fdt_region.c.
 * Use correct spelling of "U-Boot".
 * Replace tests of "! <var>" with "!<var>".
 * Replace "libfdt_env.h" with <libfdt_env.h>.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Acked-by: Simon Glass <sjg@chromium.org>

These have been sent upstream but not accepted to libfdt. For now, bring
these into U-Boot to enable fdtgrep to operate. We will use fdtgrep to
cut device tree files down for SPL.

Signed-off-by: Simon Glass <sjg@chromium.org>

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>