The existing zstd API requires the same sequence of calls to perform its
task. Create a helper for U-Boot, to avoid code duplication, as is done
with other compression algorithms. Make use of of this from the image
code.
Note that the zstd code lacks a test in test/compression.c and this should
be added by the maintainer.
Signed-off-by: Simon Glass <sjg@chromium.org>
Add the zstd library from Linux kernel (only decompression support).
There are minimal changes to build with U-Boot, otherwise the files are
identical to Linux commit dc35da16 from March 2018, the files had not
been touched since in kernel. Also SPDX lincese tags were added.
Signed-off-by: Marek Behún <marek.behun@nic.cz>
