[U-Boot] [PATCH v4 0/3] arm: tegra: apalis-tk1 and ext clock loopback

[Alexander Graf]

On 21/03/2017 14:37, Marcel Ziswiler wrote:
> Hi Alex
>
> On Tue, 2017-03-21 at 10:46 +0100, Alexander Graf wrote:
>>
>> On 21/03/2017 10:29, Marcel Ziswiler wrote:
>>> This series adds support for the Toradex Apalis TK1 and introduces
>>> a new
>>> option to disable the external clock loopback on SDMMC3.
>>>
>>> The whole series is also available here:
>>>
>>> http://git.toradex.com/cgit/u-boot-toradex.git/log/?h=for-next
>>>
>>> Changes in v4:
>>> - Re-based.
>>> - Drop patches 2 and 3:
>>>     mmc: tegra: move CONFIG_TEGRA_MMC from headers to defconfigs
>>>     mmc: tegra: introduce CONFIG_TEGRA_MMC to Kconfig
>>>   in favor of commit 1d2c0506d31a9997e5ffc22e90942902f673b107
>>>     mmc: move more driver config options to Kconfig
>>>   from Masahiro.
>>> - Meld patch 6
>>>     apalis-tk1: clean-up defconfig
>>>   into first one.
>>> - Add distro boot fallback.
>>> - Enable FIT and device tree overlay support.
>>> - Explicitly drop EFI loader support.
>>
>> Any particular reason for this?
>
> Yes, a waste of 20K which on some of our modules is rather crucial. I
> personally think force enabling EFI for everything was not too smart an
> idea but whatever.

Well, it's enabled by default for a good reason: Compatibility. I want 
to move to a world where people can just take a random distribution and 
expect it to work, rather than waste weeks over weeks on fiddling around 
with random BSPs that nobody really wants only to realize 2 years down 
the road that their security footprint is en par with a swiss cheese.

It's also the preferred option to boot BSD for example.

So how bad are the 20k for you? In fact, I'm surprised it's 20k at all - 
it used to be 10k. The overhead of DM should be much higher and I doubt 
you want to disable that ;). Usually a full U-Boot build is ~500k, so 
even at 20k we're talking about 4% - less than a compiler update usually 
gets you.

If size really is such a big concern, moving to THUMB code is going to 
buy you much more in storage savings than dropping (quite useful) UEFI 
support.

If however there are real technical issues with it, I'm happy to hear 
them and fix them as far as possible.


Alex