WARNING!!!!! i915 driver crashes when loading (KMS driver).
Could not use GRUB or SeaBIOS; SeaBIOS hangs and USB input
fails in GRUB. U-Boot UEFI works, you can boot things.
If you want to set upp a headless service this machine is
totally fine, because you can just avoid loading i915 in
Linux, and just use the EFI framebuffer or the coreboot
framebuffer, or possibly boot xorg with nomodeset.

DO NOT MERGE! This machine needs a lot work work.

Initial notes:

This should cover both the M920q and M920x, though the
x variant is quite rare.

This is a mITX desktop system, documented here:
https://doc.coreboot.org/mainboard/lenovo/m920q.html

Thanks go to Maciej Pijanowski, who ported coreboot to
this board and submitted the code upstream. Libreboot is
using the version that was recently merged upstream in
the coreboot project.

It's not yet known how to auto-download the ME, because the
update images are incomplete. The only reliable way thus far
is to extract the factory dump. However, it's also uncertain
what modules to whitelist in me_cleaner, so for this board, we
only:

* Unlock all IFD regions, setting them read-write
* Set the HAP bit, which is functionally equivalent to
  a valid me_cleaner setup

The result will be a disabled ME, and read-write operation.
No binary images will be provided for now, in releases. You
must also create the directory:

dump/m920q/

Then just extract from the factory dump using:

./ifdtool --platform cnl -x libreboot.rom

Then just stick the files that it creates into there, and
the build should work. I've made lbmk automatically set the
HAP bit and unlock regions, when building with these.

Also, SeaBIOS hung so I restored the possibility of using
GRUB as primary, but GRUB USB input also didn't work! The
board's port author tested edk2 only, it seems. I don't really
want edk2 in lbmk just for this board.

So, I made U-Boot the only payload. It seems to work fine.
However, Debian Linux and OpenBSD both seemed to completely fail:
On OpenBSD it had errors pertaining to i915 video driver.

Debian Linux stalled at startup just when it's switching to
KMS, which would use the i915 driver.

Arch Linux installer, same thing: uses KMS, and failed.

The port author said edk2 was tested. edk2 provides a decent
GOP implementation, so maybe they were using an EFI framebuffer
when booting Linux.

Signed-off-by: Leah Rowe <leah@libreboot.org>

Libreboot's binary blob reduction policy is crystal clear:

If a blob can be avoided, it must be avoided.

The ThinkPad T480 was using Intel's VGA ROM for graphics
initialisation very briefly, before Mate fixed libgfxinit.

Since libgfxinit is fixed, the Intel VGA ROM is obsolete,
so we should not be handling this at all.

Similarly, the Nvidia ROM handling has been removed, because
Mate is hard-disabling that in the coreboot code anyway, since
the Nvidia dGPU didn't work when tested anyway.

Even if it did, Libreboot's blob policy makes it clear
that Intel graphics with native init from coreboot is to
be the preferred option.

Signed-off-by: Leah Rowe <leah@libreboot.org>

This uses the excellent deguard utility, written by
the excellent Mate Kukri.

A few bugs but it mostly works. Documentation to come
shortly, in lbwww.git.

Signed-off-by: Leah Rowe <leah@libreboot.org>

I'm adding ThinkPad T480 support next, which requires
the new revision of deguard. Mate Kukri changed the way
deguard is used, in a rewrite of the project, so lbmk
has to change too.

Signed-off-by: Leah Rowe <leah@libreboot.org>

Since U-Boot must be inserted at a specific offset, it's
theoretically possible that other files might overlap, but
cbfstool will work around wherever U-Boot was inserted if
it was inserted first; we don't use specific offsets for
the other files.

This is technically a preventative bug fix, but it fixes
a bug that would probably never occur in practise.

Signed-off-by: Leah Rowe <leah@libreboot.org>

This is not a main script, and should not be treated as such;
it must never be directly executed by the user.

This script was only ever used inside other scripts, so the
shebang didn't seem to do much at all, but it shouldn't be
there anyway.

Remove it.

Signed-off-by: Leah Rowe <leah@libreboot.org>

Otherwise, you get "normal_normal" in the image name.

Signed-off-by: Leah Rowe <leah@libreboot.org>

The "normal" mode in lbmk is where no built-in GPU exists,
or no libgfxinit is used, and SeaBIOS is the first payload,
and SeaBIOS executes VGA ROMs (can't know if it'll start
in VESA or text mode).

U-Boot needs a VESA framebuffer or native coreboot
framebuffer to work correctly.

Signed-off-by: Leah Rowe <leah@libreboot.org>

U-Boot needs a VESA framebuffer or native coreboot
framebuffer to work properly.

Signed-off-by: Leah Rowe <leah@libreboot.org>

Same concept as SeaGRUB, but for U-Boot. SeaBIOS starts, but
has a bootorder file loading U-Boot first, from flash.

You can interrupt it with the ESC menu, to boot something else
in SeaBIOS, including GRUB.

With this, we can effectively provide extremely user-friendly
UEFI-first setups in Libreboot.

Take that, edk2!

Signed-off-by: Leah Rowe <leah@libreboot.org>