[PATCH 02/11] distro_bootcmd: Add SF support

[Jagan Teki]

On Mon, Jan 20, 2020 at 11:10 PM Alexander Graf <agraf at csgraf.de> wrote:
>
>
> On 20.01.20 18:22, Tom Rini wrote:
> > +A few people that may have insight to my question
> >
> > On Sat, Dec 21, 2019 at 01:24:31PM +0530, Jagan Teki wrote:
> >
> >> Add distro boot command support for SPI flash.
> >>
> >> This distro boot will read the boot script at specific
> >> location at the flash and start sourcing the same.
> >>
> >> The common macro like BOOTENV_SHARED_FLASH would help
> >> to extend the support for nand flash in future.
> >>
> >> Cc: Tom Rini <trini at konsulko.com>
> >> Signed-off-by: Jagan Teki <jagan at amarulasolutions.com>
> > What distro is this for?  My concern here is that hundreds of boards
> > (literally) grow by a few hundred bytes to add in this bit of additional
> > default logic.  That's not a big problem if distributions are now going
> > to be using SPI flash as where they're programming in their bootscript.
> > But, who is doing that?  Thanks!
>
>
> I am not aware of any "distro" that puts a U-Boot script at offset 0 of
> the SPI Flash.
>
> Traditionally, SPI Flash boot setups were always very hand crafted -
> exactly the opposite of what distro boot is for. That said, I think
> supporting SPI Flash boot for rk3399 is great! Albeit I would personally
> only store U-Boot and the environment on SPI, not the target OS.
>
> Jagan, is putting a U-Boot script on the SPI Flash something you thought
> of or something that the rk3399 reference board already does? If it's
> the latter, maybe you could add it as a board custom boot function?

Yes it would be later that points to. rk3399 has SPI flash layout and
out of which one of offset(script_offset_f=0xffe000 from
include/configs/rk3399_common.h) stored the programming script.

Jagan.