[PATCH 02/11] distro_bootcmd: Add SF support

[Tom Rini]

On Thu, Jan 23, 2020 at 10:59:17PM +0530, Jagan Teki wrote:
> On Thu, Jan 23, 2020 at 10:45 PM Tom Rini <trini at konsulko.com> wrote:
> >
> > 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!
> 
> Not sure about the possibility more boards using this at this point,
> but I was initially created custom to rockchip and feel that it would
> be useful to rest if it's generic. May be will split into rockchip
> area if it's eating too much footprint.

Yes, the "distro boot" functionality refers to what we need to allow
boards to easily Just Work with standard off the shelf *nix
distributions.  Thanks!

-- 
Tom
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