[U-Boot] ARM64 Allwinner Binary Size

[Mark Kettenis]

> From: Andre Przywara <andre.przywara at arm.com>
> Date: Tue, 19 Dec 2017 13:38:59 +0000
> 
> Hi Maxime,
> 
> thanks for having a look!
> 
> On 19/12/17 13:12, Maxime Ripard wrote:
> > On Tue, Dec 05, 2017 at 10:28:20AM +0000, Andre Przywara wrote:
> >> So even though the actual u-boot.bin for 64-bit boards is still somewhat
> >> below the limit (~480KB), adding the ATF image (~32KB) pushes it over
> >> the edge. So since v2017.11 u-boot.itb is already too big for the
> >> traditional MMC env location.
> > 
> > So I've had a quick look about what could go possibly go away in our
> > current armv8 config (using the pine64+ defconfig). Let me know if
> > some are actually vitals:
> > 
> >  - FIT_ENABLE_SHA256_SUPPORT
> >  - CONSOLE_MUX
> >  - CMD_CRC32
> >  - CMD_LZMADEC
> >  - CMD_UNZIP
> >  - CMD_LOADB
> >  - CMD_LOADS
> >  - CMD_MISC (actually implementing the command sleep)
> >  - ISO_PARTITION (yes. For CDROMs.)
> 
> As Alex mentioned, this is needed for some installer images, which come
> as ISOs. So if possible, we should keep this in.
> 
> >  - VIDEO_BPP8, VIDEO_BPP16
> >  - VIDEO_ANSI
> >  - SHA256
> >  - LZMA
> 
> From just looking at the names I am fine with the rest gone. But let me
> test tonight if there are any side effects.
> 
> Some of them seem useful, but I would leave enabling them to the actual
> users. If someone needs it, they can enable them and loose the raw MMC
> environment. I think this is a fair trade-off.
> 
> > Removing those options make the u-boot.itb binary size going from
> > 516kB to 478kB, making it functional again *and* allowing us to enable
> > the DT overlays that seem way more important than any feature
> > mentionned above (and bumps the size to 483kB).
> 
> How important is the raw MMC environment for the ARM64 boards, actually?
> Most of the rationale for the 32-bit side seemed to apply to legacy use
> cases only. Do we have reports/complaints from 64-bit users?

For me/us (OpenBSD) the environment is still important.  I have many
setups where U-Boot lives on a uSD card but the installed OS lives on
a USB device.  In that scenario I set boot_targets to boot the EFI
bootloader and OS off the USB disk.  This is very helpfull for testing
new versions of U-Boot as I can simply swap the uSD card.  But for
some setups this is essential as OpenBSD doesn't support the SD/MCC
controller on all ARM hardware yet (but we do support it on
Allwinner).

Cheers,

Mark