[U-Boot] config: enable CONFIG_API in distro config

[Simon Glass]

Hi Dennis,

On 19 April 2014 08:42, Dennis Gilmore <dennis at ausil.us> wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On Sat, 19 Apr 2014 15:01:40 +0100
> Ian Campbell <ijc at hellion.org.uk> wrote:
>
> > On Fri, 2014-04-18 at 11:43 -0600, Simon Glass wrote:
> > > Hi Stephen,
> > >
> > > On 18 April 2014 11:23, Stephen Warren <swarren at wwwdotorg.org>
> > > wrote:
> > > > On 04/18/2014 09:35 AM, Tom Rini wrote:
> > > >> On Thu, Apr 10, 2014 at 03:55:48PM -0500, Rob Herring wrote:
> > > >>
> > > >>> From: Rob Herring <robh at kernel.org>
> > > >>>
> > > >>> CONFIG_API is needed for u-boot apps such as grub2, so enable
> > > >>> it for distro config.
> > > >>>
> > > >>> Cc: Dennis Gilmore <dennis at ausil.us>
> > > >>> Signed-off-by: Rob Herring <robh at kernel.org>
> > > >>
> > > >> This breaks a number of boards that have opted in to the distro
> > > >> config. The full list is:
> > > >> whistler trimslice beaver tec paz00 ventana cardhu harmony
> > > >> dalmore plutux medcom-wide rpi_b venice2 colibri_t20_iris tec-ng
> > > >> seaboard
> > > >>
> > > >> How do you guys want to handle this?  I can apply now and they
> > > >> can be fixed up later, or I can wait for fixup patches to come
> > > >> out and apply them all at once.  Thanks!
> > > >
> > > > I've sent patches that solve all the build problems on Tegra with
> > > > CONFIG_API enabled.
> > > >
> > > > That said, I still conceptually object to config_distro_defaults.h
> > > > enabling API support in order to support grub; I believe the
> > > > distros need to get together and nail down a *single* boot
> > > > mechanism to standardize upon, rather than having Fedora support
> > > > BootloaderSpec, Ubuntu/Linaro(?) support Grub, something else
> > > > support LILO, something else support UEFI,
> >
> > AIUI the distros *are* standardising: on grub2.
>
> not in arm space at least,
>

I have no great love for grub2 and the pain of not using on ARM devices
would in my case succumb to an extremely small aspirin.


> > AIUI BootloaderSpec is a spec to standardise the configuration of
> > UEFI. It is used to install the distro's bootloader (often grub2)
> > into the UEFI boot list, for grub-on-UEFI scenarios.
>
> not at all true, bootloader spec is designed to be a platform and
> bootloader agnostic way to boot open systems. its designed to
> share /boot between open operating systems, UEFI, bios, u-boot etc have
> zero to do with it. you can compliantly boot operating systems using
> any type of platform
>
> > Where the lowlevel firmware is u-boot then they want to use grub2 on
> > it so that things are consistently grub no matter whether the
> > platform uses UEFI, u-boot, PC BIOS etc.
> >
> > >  etc. Without this, we'll force every U-Boot binary to
> > > > be bloated with all kinds of redundant code. Having a single
> > > > standard mechanism was always the point of
> > > > config_distro_defaults.h in my mind. If we really need Grub
> > > > support, wouldn't it be better to have U-Boot parse and execute
> > > > grub.cfg, just like it does extlinux.cfg?
> > >
> > > That seems to make a lot more sense to me. How hard can it possibly
> > > be?
> >
> > Very. grub.cfg is essentially a complete bash-a-like programming
> > language. At work we try to parse it for Xen's "pygrub" utility and it
> > breaks pretty frequently when people introduce random new variables
> > etc.
>
> Which is why we are standardising distro booting using u-boots syslinux
> compatibility in distro land.  it's not uncommon to users, since isos
> have used isolinux for years. right now its feature set is somewhat
> simple. but over time we should be able to do things like commandline
> editing and using menu to select different kernels.  But there is a
> very solid foundation available today that works really well.
>

Can you suggest a starting point for trying this out on am ARM platform?
(e.g. OMAP, Tegra, Exynos) I'd like to see how it works.

>
> AFAIK no one is really working on grub2 for use with u-boot as linaro
> who was doing the work have decided to drop u-boot support and only do
> UEFI.
>

So UEFI boots through grub2? We seem to have a talent for making things
complicated?

Regards,
Simon