This function is useful to merge a subset of DT into another DT, for
example if some prior-stage firmware passes a DT fragment to U-Boot
and U-Boot needs to merge it into its own DT. Export this function
to permit implementing such functionality.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Cc: Simon Glass <sjg@chromium.org>
Cc: Tom Rini <trini@konsulko.com>

In upstream libfdt, 6dcb8ba4 "libfdt: Add helpers for accessing
unaligned words" introduced changes to support unaligned reads for ARM
platforms and 11738cf01f15 "libfdt: Don't use memcpy to handle unaligned
reads on ARM" improved the performance of these helpers.

In practice however, this only occurs when the user has forced the
device tree to be placed in memory in a non-aligned way, which in turn
violates both our rules and the Linux Kernel rules for how things must
reside in memory to function.

This "in practice" part is important as handling these other cases adds
visible (1 second or more) delay to boot in what would be considered the
fast path of the code.

Cc: Patrice CHOTARD <patrice.chotard@st.com>
Cc: Patrick DELAUNAY <patrick.delaunay@st.com>
Link: https://www.spinics.net/lists/devicetree-compiler/msg02972.html
Signed-off-by: Tom Rini <trini@konsulko.com>
Tested-by: Patrice Chotard <patrice.chotard@st.com>

Bring over the fdt from this commit:

430419c (origin/master) tests: fix some python warnings

adding in the 'assumptions' series designed to reduce code size.

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

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>

The commit "libfdt: fdt_address_cells() and fdt_size_cells()" introduced
a bug as it consolidated code between the helpers for getting
be 0, and is frequently found so in practice for /cpus.  IEEE1275 only
requires implementations to handle 1..4 for #address-cells, although one
could make a case for #address-cells == #size-cells == 0 being used to
represent a bridge with a single port.

While we're there, it's not totally obvious that the existing implicit
cast of a u32 to int will give the correct results according to strict C,
although it does work in practice.  Straighten that up to cast only after
we've made our range checks.

This is based on upstream commit:
b8d6eca ("libfdt: Allow #size-cells of 0")
but misses the test cases,as we don't implement them in U-Boot.

Signed-off-by: Matthias Brugger <mbrugger@suse.com>

According to the device tree specification, the default value for
was not present.

This patch also makes fdt_address_cells() and fdt_size_cells() conform
to the behaviour documented in libfdt.h. The defaults are only returned
if fdt_getprop() returns -FDT_ERR_NOTFOUND, otherwise the actual error
is returned.

This is based on upstream commit:
aa7254d ("libfdt: return correct value if #size-cells property is not present")
but misses the test case part, as we don't implement them in U-Boot.

Signed-off-by: Matthias Brugger <mbrugger@suse.com>

Add internal fdt_cells() to avoid copy and paste. Fix typo in
fdt_size_cells() documentation comment.

This is based in upstream commit:
c12b2b0 ("libfdt: fdt_address_cells() and fdt_size_cells()")
but misses the test cases, as we don't implement them in U-Boot.

Signed-off-by: Matthias Brugger <mbrugger@suse.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

At present this function appears to copy only the data before the struct
region and the data in the string region. It does not seem to copy the
struct region itself.

>From the arguments of this function it seems that it should support fdt
and buf being different. This patch attempts to fix this problem.

Upstream commit: c72fa77 libfdt: Copy the struct region in fdt_resize()

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

The new fdt_generate_phandle() function can be used to generate a new,
unused phandle given a specific device tree blob. The implementation is
somewhat naive in that it simply walks the entire device tree to find
the highest phandle value and then returns a phandle value one higher
than that. A more clever implementation might try to find holes in the
current set of phandle values and fill them. But this implementation is
relatively simple and works reliably.

Also add a test that validates that phandles generated by this new API
are indeed unique.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

This provides various patches sent to the devicetree-compiler mailing list
to enhance the Python bindings. A final version of this patch may be
created once upstreaming is complete, but if it takes too long, this can
act as a placeholder.

New pylibfdt features:
- Support for most remaining, relevant libfdt functions
- Support for sequential-write functions

Changes are applied to existing U-Boot tools as needed.

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