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

[Ian Campbell]

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.

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.

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.

Ian.