We use the terms 'distro' to mean extlinux but they are not really the
same. 'Distro' could refer to any method of booting a distribution,
whereas extlinux is a particular method.

Also we sometimes use syslinux, but it is better to use the same term in
all cases.

Rename distro to syslinux and also update bootstd uses of syslinux to use
extlinux instead.

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

In a few cases the error handling is not quite right. Make sure we
return the actual error in distro_efi_read_bootflow_file() rather than
-EINVAL. Return -IO when a file cannot be read. Also show the error name
if available.

This does not change operation, but does make it easier to diagnose
problems.

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

These flags actually relate to the iterator, not the bootflow struct
itself. Rename them.

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

This function is not used outside tests. Drop it and rename
bootflow_scan_dev() since it is how we start a scan now.

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

We want to support scanning a single label, like 'mmc' or 'usb0'. Add
this feature by plumbing the label through to the iterator, setting a
flag to indicate that only siblings of the initial device should be used.

This means that scanning a bootdev by its name is not supported anymore.
That feature doesn't seem very useful in practice, so it is no great loss.

Add a test for bootdev_find_by_any() while we are here.

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

At present we set up the bootdev order at the start, then scan the
bootdevs one by one.

However this approach cannot be used with hunters, since the bootdevs may
not exist until the hunter is used. Nor can we just run all the hunters at
the start, since that violate's U-Boot's 'lazy init' requirement. It also
increases boot time.

So we need to adjust the algorithm to scan by labels instead. As a first
step, drop the dev_order[] array in favour of a list of labels. Update the
name of bootdev_setup_iter_order() to better reflect what it does.

Update some related comments and log messages. Also disable a few tests
until a later commit where we can use them.

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

This needs to run before any bootdev is used, so add a hunter for it.

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

Some bootmeths provide a way to load a device tree as well as the base
OS image. Add a way to store this in the bootflow. Update the
'bootflow info' command to show this information.

Note that the device tree is not allocated, but instead is stored at
an address provided by an environment variable. This may need to be
adjusted at some point, but for now it works well and fits in with the
existing distro-boot scripts.

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

At present all partitions are scanned, whether marked bootable or not.
Use only bootable partitions, defaulting to partition 1 if none is
found.

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

If a disk has a bootable partition we are expected to use it to locate the
boot files. Add a function to find it.

To test this, update mmc1 to have two paritions, fixing up other tests
accordingly.

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