[PATCH] configs: layerscape: Disable the EFI_LOADER feature

[Z.Q. Hou]

Hi Michael,

> -----Original Message-----
> From: Michael Walle <michael at walle.cc>
> Sent: 2021年7月23日 1:01
> To: Tom Rini <trini at konsulko.com>
> Cc: Z.Q. Hou <zhiqiang.hou at nxp.com>; Heinrich Schuchardt
> <xypron.glpk at gmx.de>; u-boot at lists.denx.de; Priyanka Jain
> <priyanka.jain at nxp.com>
> Subject: Re: [PATCH] configs: layerscape: Disable the EFI_LOADER feature
> 
> Am 2021-07-22 17:26, schrieb Tom Rini:
> > On Thu, Jul 22, 2021 at 02:25:59PM +0800, Zhiqiang Hou wrote:
> >
> >> From: Hou Zhiqiang <Zhiqiang.Hou at nxp.com>
> >>
> >> The feature BOOTENV_SHARED_EFI is not supported on layerscape
> boards,
> >> it didn't result kernel boot crash previously since there isn't the
> >> efi/boot/"BOOTEFI_NAME" and it skip calling of 'boot_efi_binary'.
> >>
> >> But since the commit f3866909e350 ("distro_bootcmd: call EFI bootmgr
> >> even without having /EFI/boot"), it will cause kernel boot crash as
> >> there isn't a valid fdt_addr and it finially uses the device tree
> >> blob of U-Boot and further cause errors.
> >>
> >> As this feature is enabled by default for armv7 and armv8, so disable
> >> it explicitly to avoid calling the 'scan_dev_for_efi'.
> >
> > I'm not thrilled with this.  Why isn't the solution to get and keep in
> > sync the device trees, so that the tree U-Boot has is valid for the
> > kernel?  I'm also open to discussing f3866909e350 more.  But I'm
> > really opposed to disabling EFI_LOADER on modern platforms as that
> > will make adoption of U-Boot in device harder I feel.
> 
> I don't know whats going on with the NXP boards, but the sl28 is a
> layerscape board it is working pretty well with EFI boot.

Do you mean the EFI boot work well on sl28? Or the EFI boot doesn't break other boot ways?

In my case, there are 4 MMC partitions and a boot script with boot images in the 2nd partition, while nothing in the 1st partition. So the expected boot flow is the 'bootcmd_mmc0' scan the 1st partition and find it's not bootable and then the 2nd partition and boot with the script. But actually the 'scan_dev_for_efi' got problem when scan the 1st partition, as the u-boot DTB is used in 'bootefi bootmgr' and result in some error related to the DTB.

Actually, if give a readable but invalid 'fdt_addr' in env, the EFI boot can also be skipped during the scan of the 1st partition. Actually on some Layerscape boards the provided env 'fdt_addr' with a non-readable address, and on other boards a readable 'fdt_addr'. Seems the patch author copy them from somewhere but didn't cause issue that time. But this is just a workaround, the EFI boot should not cause problem during the scan phase when there isn't needed components in one of these partitions.

Thanks,
Zhiqiang

> 
> So why don't you fix the root cause instead of disabling this feature?
> 
> -michael