[U-Boot] disabling mmc in spl when booting using bootrom

[Sandy Patterson]

On Fri, Aug 12, 2016 at 1:20 PM, Simon Glass <sjg at chromium.org> wrote:

> Hi Ziyuan,
>
> On 11 August 2016 at 05:35, Ziyuan Xu <xzy.xu at rock-chips.com> wrote:
> >
> >
> > On 2016年08月11日 19:31, Sandy Patterson wrote:
> >>
> >> Simon,
> >>
> >> I am trying to format a patch to disable MMC in the SPL if booting main
> >> u-boot using BOOTROM, therefore the SPL MMC isn't needed.
> >>
> >> Is the best solution to wrap every header file (rock2.h
> firefly-rk3288.h,
> >> etc) with ifdefs on the BACK_TO_BROM define? Or would it be better to
> move
> >> the SPL MMC define into rk3288-common.h and just have chromebook_jerry
> undef
> >> it like it does the SPL GPIO code.
> >>
> >> With that change, enabling BOOT_TO_BROM shrinks the spl from 32K to 23K.
> >
> > Note that, firefly-rk3288 use OF_PLATDATA, we will use
> u-boot-spl-no-dtb.bin
> > instead of u-boot-spl-dtb.bin, and the size of u-boot-spl-no-dtb.bin is
> > almost 23K.
> >
> > @Simon, I think we will update doc/README.rockchip if you insist on
> > OF_PLATDATA for firefly-rk3288. we no longer use u-boot-spl-dtb.bin.:-)
>
> I don't insist :-)
>
> I really don't like OF_PLATDATA. But it cuts the size down a lot
> (~6KB) and we are otherwise always running out of space on rk3288.
>
> If there is a better idea, let's have it. Otherwise, yes we can update the
> docs.
>

@Ziyuan, I did my testing on rock2 which doesn't use OF_PLATDATA, the
firefly
board should see the same final size which is roughly equivalent to the
current
firefly SPL size.

We ran out of space in SPL. I too was afraid of using OF_PLATDATA mostly
from
Simon's commit message.

I would propose moving to using the BOOTROM to load U-Boot proper. You
shouldn't
need any of the media drivers since the BOOTROM was already able to load
the SPL
it should be fine loading the full U-Boot.

I get 9K from removing MMC from rock2. I'm happy to write a patch that
applies this logic
to the remainder of the rk3288 boards if that's the way you'd like to go.
You could test it by
enabling the BOOT_TO_BROM config.


>
> Regards,
> Simon
>