Both SHA1 and (especially) MD5 are no longer as safe as they once were for
cryptographic use. Replaces examples which use them with examples using
SHA256 instead. This will provide more-secure defaults for users who use
documentation examples as a base for their own use. This is not too
necessary for non-verified-boot scenarios (since someone could just replace
the checksum), but I wanted to be complete.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

The current name is inconsistent with SPL which uses CONFIG_SPL_TEXT_BASE
and this makes it imposible to use CONFIG_VAL().

Rename it to resolve this problem.

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

With the new 2021.04 we have a new version of Chromium OS boot, which
supports sandbox, coral and coral-on-coreboot. Add documentation for
this.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

Two external references cannot have the same name:

doc/chromium/overview.rst:5:
WARNING: Duplicate explicit target name: "youtube"

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>

Move this documentation over to reST. Move the example files into a files/
directory so they are still separate.

Do a few minor updates while we are here:
- Tidy up sandbox build instructions
- Update my github account name
- Add some talks and links

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

Without this padding nyan-big ends at a blank screen on boot.
Details on how to get to this padding can be found in the README.chromium under Notes.

Signed-off-by: Tristan Bastian <tristan-c.bastian@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>

The DT spec demands a unit-address in a node name to match the "reg"
property in that node. Newer dtc versions will throw warnings if this is
not the case.
Fix all occurences in various documentation files where this was not
observed, to not give bad examples to the reader.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>

Add a sample .its file for booting U-Boot on a jerry Chromebook.

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

Most Chromebooks support chain-loading U-Boot but instructions are
somewhat scattered. Add a README to hold this information within the
U-Boot tree. Also add the standard developer keys to simplify the
instructions, since they are small.

For now this only supports nyan-big.

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

Add a sample .its file for booting U-Boot on a nyan-big Chromebook.

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