[PATCH 02/11] distro_bootcmd: Add SF support

Jagan Teki
2020-01-23T17:11:15Z

On Thu, Jan 23, 2020 at 10:33 PM Tom Rini <trini@konsulko.com> wrote:
>
> On Thu, Jan 23, 2020 at 10:25:50PM +0530, Jagan Teki wrote:
> > On Mon, Jan 20, 2020 at 11:10 PM Alexander Graf <agraf@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@konsulko.com>
> > > >> Signed-off-by: Jagan Teki <jagan@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.
>
> So I'm not sure why we're adding distro boot support to SPI flash. What
> is the reference platform storing there exactly? Thanks!

I'm not sure I understand the question? we have rk3399 SBC's that boot
from SPI and have feasibility to run distro boot using programming
script store in flash offset like boot.scr does for MMC.