Use only a single -machine parameter.

Describe that the same invocation of qemu-system-<arch> has to be
used for dumping the device-tree as will be used when executing U-Boot.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

Recently we are introducing multiple git subtree projects and
it is the right time to have a universal script to update
various subtrees and replace the dts/update-dts-subtree.sh.

update-subtree.sh is a wrapper of git subtree commands.

Usage: From U-Boot top directory,
run
$ ./tools/update-subtree.sh pull <subtree-name> <release-tag>
for pulling a tag from the upstream.
Or run
$ ./tools/update-subtree.sh pick <subtree-name> <commit-id>
for cherry-pick a commit from the upstream.

Currently <subtree-name> supports dts, mbedtls and lwip.

Signed-off-by: Raymond Mao <raymond.mao@linaro.org>

Document the logic of when we do a full resync of the device trees used
by OF_UPSTREAM as well as that cherry-picking is allowed as needed.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>

Short reference link names like "dtspec", "dtrepo", "dttweaks" etc.
interrupt the flow of the document text. Lets avoid them and instead
expand in place for better readability.

Suggested-by: Paul Barker <paul.barker.ct@bp.renesas.com>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Paul Barker <paul.barker.ct@bp.renesas.com>

Encourage SoC/board maintainers to migrate to using devicetree-rebasing
subtree and maintain a regular sync with Linux kernel devicetree files
and bindings.

Along with that add documentation regarding how to run DT bindings
schema checks.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>

Since U-Boot switched away from manual CONFIG_* defines to Kconfig
options, align devicetree documentation accordingly.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>

Standard passage provides for a bloblist to be passed from one firmware
phase to the next. That can be used to pass the devicetree along as well.
Add an option to support this.

Tests for this will be added as part of the Universal Payload work.

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

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

Fix typo and whitespace in the document.

Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>