This commit adds support for the MacBook Air 4,2 from
Apple, circa 2011. This is a blobless board in coreboot,
when configured the way Libreboot does it, except for
the presence of neutered ME (via me_cleaner) and (per
Libreboot project policy), CPU microcode updates.

Intel ME image automatically extracted from Apple EFI
updates, via the same blobutil script used for fetching
Lenovo ME updates. This means that the user does not
have to extract it from a dump of the original firmware,
when flashing Libreboot.

Apple EFI updates are .dmg files, which are LZMA
compressed archives containing executables and files.
When the archive is de-compressed, more compressed
archives shall be found inside.

The file targeted (from Apple) contains Apple's EFI
firmware update program, that the user runs in MacOS,
but we don't care about running that. No, we are only
interested in Apple's ME update image, which we extract
as `me.bin` and then run through me_cleaner.

This has to be done through brute force, because the
location of that file is random, with the .dmg file.
The script systematically (and recursively) scans the
file, trying me_cleaner on files inside first, before
attempting extraction with 7z; if me_cleaner passes,
then we've found the me.bin file, or if 7z passes, we
scan the resulting directory; if neither pass, or the
directory created by 7z is finished being scanned, the
next file or directory is scanned.

When the script encounters a directory in each iteration
of the loop, that directory is scanned.

I wonder if a non-recursive method would be feasible in
shell scripts. This method shouldn't pose any problems,
though.

When using e.g. -p grub in build/boot/roms, it will
error out. This patch fixes that.

E.g.

./build boot roms t440pmrc_12mb -p grub

Seldom used feature and it was overlooked. Most people
won't use the option that triggered the error.

these boards are almost impossible to find, and have always been
buggy, it doesn't look like there will be any viable testing or
development on it

it's currently broken in master, on coreboot. if someone wants to
fix and re-add to lbmk, they can do that

use older libreboot releases to flash this board, if you wish

(i *am* adding te the issue tracker, a note about this commit,
with a view to re-adding it one day)

rename board configs, and add to sources file the
t530/w530 boards

in some situations, the files weren't being downloaded

MRC caches in a certain way, that Heads was able to work
around in their build system, for this board.

I've adapted the relevant config differences, from their project
as of heads revision 96440b928acb06de5b925ea12014c9c280b23165

The downside is that CBFS now has to be 8MB in size. The upside
is that the machine also boots much faster

See:

    https://github.com/osresearch/heads/pull/1282/commits/f0792117efa177ded19878f652c5a28e8cc62a71

    https://github.com/osresearch/heads/pull/1282#issuecomment-1400634600

I have not adapted their IFD changes, versus Libreboot, because theirs
simply has a different version string, and uses different read/write
permission bits for regions as defined in the IFD.

This affects:

    t440p_12mb_mrc

    w541_12mb_mrc

S3 suspend/resume still broken on these targets which use the libre
MRC init (replacement code by Angel Pons, recently merged in lbmk):

    t440p_12mb

    w541_12mb

With clever use of FMAP, the rest of the BIOS region might still be
used. However, for our purposes, 8MB CBFS will do just fine.

Heads's changes configure MRC so that caching is handled properly,
for when the machine returns from sleep. Setting CBFS to be any
higher will result in slower boot times, and broken S3 resume, due
to MRC cache misalignment (this is based on my understanding, reading
through the Heads project looking at their research on this).

At some point in the future, Angel's libre MRC code will probably
be finished, and merged, with more fine tuning possible to allow
bigger CBFS sizes.

libre mrc on haswell is quite buggy for now, but works in
a limited fashion

this patch re-adds the old configs, but as _mrc for example
t440p_12mb_mrc instead of t440p_12mb

and t440p_12mb (without _mrc) still uses the libre mrc code

i found that with libre mrc, usb was broken in grub

however, it worked nicely in seabios

for our purposes, doing seabios-only roms in text mode
is best for now

i'm going to re-add mrc.bin, but for t440p_12mb_mrc
and w541_12mb_mrc, as new config names. the regular
t440p_12mb and w541_12mb will continue to use libre
mrc, but the _mrc ones will use mrc.bin and retain the
grub payload in board.cfg

untested. removing.

courtesy of Angel Pons from the coreboot project

this uses the following patch set from gerrit, as yet
unmerged (in coreboot master) on this date:

    https://review.coreboot.org/c/coreboot/+/64198/5

logic for downloading mrc blobs has been deleted from
lbmk, as this is now completely obsolete (for haswell
boards)

if other platforms are added later that need mrc.bin,
then logic will be re-added again for that

this fixes the build error:

Error: name not set
Usage: ./download gitmodule [name]

when running:

./download all

running "all" runs all scripts under downloads,
one of which was the gitmodule script itself, therefore
being run without argument

they don't even boot in pcbox properly, and the real
hardware is not much to talk about

useless port

delete

reduce the number of calls to read() by using
bit shifts. when rnum is zero, read again. in
most cases, a nibble will not be zero, so this
will usually result in about 13-15 of of 16
nibbles being used. this is in comparison to
8 nibbles being used before, which means that
the number of calls to read() are roughly
halved. at the same time, the extra amount of
logic is minimal (and probably less) when
compiled, outside of calls to read(), because
shifting is better optimised (on 64-bit machines,
the uint64_t will be shifted with just a single
instruction, if the compiler is decent), whereas
the alternative would be to always precisely use
exactly 16 nibbles by counting up to 16, which
would involve the use of an and mask and still
need a shift, plus...

you get the point. this is probably the most
efficient code ever written, for generating
random numbers between the value of 0 and 15

some checks check for specific utils, which are
then used to indicate the existence of other utils,
which means that building them singularly, as is
currently done, may result in errors later if another
tool doesn't exist compiled yet

this is an obscure bug, fixed by this patch. more of a
workaround really. a dirty hack. when checking for any
of the coreboot utilities required, build all coreboot
utilities that are possibly required

the utilities are small enough that this does not add
much extra time to build, and in most cases, all of them
will be needed anyway

using the same method as the previous patch for t440p

352MB VRAM causes stability issues, according to some reports

users can still set it to the higher level when building, if
they wish to

U-Boot can be configured via environment variables which can be saved to
various storage devices. This usually defaults to MMC or SPI depending
on where it boots from, but assumes the device's layout is controlled by
U-Boot.

We should store the environment in SPI flash, but we also need to
configure coreboot FMAPs to reserve the area U-Boot would use as its
environment storage. For now, disable environment storage by setting
ENV_IS_NOWHERE=y to avoid overwriting random regions of SPI or MMC if
someone tries to save the variables.

Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>

Set default U-Boot revision to v2023.01 and rebase patches on top of
that. Upstream kconfig status is a bit unstable, so updating configs
with `make oldconfig` would miss important upstream changes.

For each board, run `make savedefconfig` and `diffconfig -m` at the old
version to get a diff from upstream defconfigs. Fix those affected by
upstream changes, like SYS_TEXT_BASE being renamed to TEXT_BASE. Then
append those to the new version's defconfigs and run `make olddefconfig`
to get updated configs.

Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>