[PATCH 02/11] distro_bootcmd: Add SF support

[Tom Rini]

On Thu, Jan 23, 2020 at 10:41:15PM +0530, Jagan Teki wrote:
> On Thu, Jan 23, 2020 at 10:33 PM Tom Rini <trini at 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 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.
> >
> > 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.

OK, and what distro(s) today are doing that?  I'm not happy with this
patch as it's growing hundreds (literally) of boards in size and I'd
like to know what is leveraging this functionality today, or is going to
be as soon as it's upstream and widely available.  Thanks!

-- 
Tom
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