Re: [PATCH 02/11] distro_bootcmd: Add SF support

From: Tom Rini <trini@konsulko.com>
To: Jagan Teki <jagan@amarulasolutions.com>
Cc: "open list:ARM/Rockchip SoC..."
	<linux-rockchip@lists.infradead.org>,
	Heinrich Schuchardt <xypron.glpk@gmx.de>,
	U-Boot-Denx <u-boot@lists.denx.de>,
	Alexander Graf <agraf@csgraf.de>,
	linux-amarula <linux-amarula@amarulasolutions.com>
Subject: Re: [PATCH 02/11] distro_bootcmd: Add SF support
Date: Thu, 23 Jan 2020 12:03:01 -0500	[thread overview]
Message-ID: <20200123170301.GX26536@bill-the-cat> (raw)
In-Reply-To: <CAMty3ZAq+aDMuEKGYk9UyTS4Z4=TgtNcKRDtiBC-=mqRWUWAyA@mail.gmail.com>

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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!

-- 
Tom

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