Two bugs have appeared:

- arguments can have an equals sign embedded in them, which must be
  considered part of the value
- arguments must fully match the name; partial matches should be
  ignored

Fix these and add a test to cover both.

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

Prepare v2023.10-rc4

The existing distro scripts check extlinux and scripts before EFI. Adjust
the default ordering to do the same, to avoid breaking existing flows.

Add some documentation, mentioning that this order will likely change in
future.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reported-by: Da Xue <da@libre.computer>

The existing ChromiumOS bootmeth only supports reading a single kernel
partition, either 2 or 4. In fact there are normally two options
available.

Use the GUID to detect kernel partitions, with the BOOTMETHF_ANY_PART
flag, so that bootstd does not require a valid filesystem before calling
the bootmeth.

Tidy up and improve the logging while we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>
Suggested-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
[trini: Add missing select of PARTITION_TYPE_GUID]
Signed-off-by: Tom Rini <trini@konsulko.com>

The ChromiumOS bootmeth has no tests at present. Before adding more
features. add a basic test.

This creates a disk which can be scanned by the bootmeth, so make sure
things work. It is quite rudimentary, since the kernel is faked, the root
disk is missing and there is no cmdline stored.

Enable the bootmeth for snow so it can build the unit test.

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

We currently use mmc4 for tests. Update the function which sets this up
so that it can handle any device.

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

At present 'bootflow list' shows <NULL> for the filename when it is not
present. Show an empty string instead, since that is more user-friendly.

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

Add a bootflow command to update the command line more easily. This allows
changing a particular parameter rather than editing a very long strings.
It is also easier to handle with scripting.

The new 'bootflow cmdline' command allows getting and setting single
parameters.

Fix up the example output while we are here, since there are a few new
items.

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

The Linux command line consists of a number of words with optional values.
At present U-Boot allows this to be changed using the bootargs environment
variable.

But this is quite painful, since the command line can be very long.

Add a function which can adjust a single field in the command line, so
that it is easier to make changes before booting.

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

Some operating systems have a command line which can be adjusted before
booting. Store this in the bootflow so it can be controlled within
U-Boot.

Fix up the example output while we are here, since there are a few new
items.

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