[PATCH 1/3] cmd: env: Add 'env import -h' for Marvell hw_info formatted environments

[Luka Kovacic]

On Fri, Feb 5, 2021 at 11:04 PM Tom Rini <trini at konsulko.com> wrote:
>
> On Fri, Feb 05, 2021 at 11:02:23PM +0100, Luka Kovacic wrote:
> > Hello Tom,
> >
> > On Thu, Feb 4, 2021 at 6:06 PM Tom Rini <trini at konsulko.com> wrote:
> > >
> > > On Thu, Feb 04, 2021 at 11:46:35AM +0100, Luka Kovacic wrote:
> > >
> > > > The '-h' flag is added to the 'env import' command to enable parsing
> > > > Marvell hw_info formatted environments.
> > > > This format is often used on Marvell Armada A37XX based devices to store
> > > > parameters like the board serial number, factory MAC addresses and some
> > > > other information.
> > > >
> > > > Currently this environment format can only be imported, not exported.
> > > > These parameters are usually written to the flash in the factory.
> > > >
> > > > This functionality has been tested on the GST ESPRESSOBin-Ultra board
> > > > successfully.
> > > >
> > > > Usage example:
> > > >  => sf probe
> > > >  => sf read ${loadaddr} 0x003E000A 0x1F0 # Read the environment from
> > > > SPI flash
> > > >  => env import -h ${loadaddr}
> > > >
> > > > Signed-off-by: Luka Kovacic <luka.kovacic at sartura.hr>
> > > > Cc: Luka Perkov <luka.perkov at sartura.hr>
> > > > Cc: Robert Marko <robert.marko at sartura.hr>
> > >
> > > So, the implementation itself is fine:
> > >
> > > Reviewed-by: Tom Rini <trini at konsulko.com>
> > >
> > > And I take it as a given that we can't get the boards populated with an
> > > existing separator, so we need to solve this somehow or another.  I am
> > > however loathe to increase every platform by a handful of bytes (help
> > > text, code text) to cover this case, and adding #ifdef around the help
> > > text in particular would be very ugly. Is there any clean way to write
> > > this as a board-specific command?  I assume the overall intention is to
> > > import the factory env for the required information, store it in regular
> > > U-Boot environment and then never touch the factory area again.  Thanks!
> >
> > I have already considered the possibility of implementing this in a
> > board-specific way, but I tried implementing it here to avoid unnecessary
> > code duplication.
> > You are correct, the intention is to use this functionality as a migration
> > path. It's good to keep the factory area intact, in case it's still needed in
> > the future.
> > The Marvell hw_info area is limited to MACs and serial numbers by the
> > stock utility.
>
> OK.  And can we put this in the board-specific path somehow, relatively
> cleanly?

I've been thinking about the following options:
 - Implementing a separate command under cmd/mvebu (hw_info), like done
in the stock U-Boot.
I'm not inclined to this one, as I don't see real utility in updating
this factory
area. A positive with this one is that it abstracts reading of the SPI flash.

 - No command, automatic migration, directly from the SPI flash (implemented
in the board.c file.
I don't see this as a clean way of doing it, the Armada A37XX board.c is
already quite full of board-specific init.

 - Implemented as is, but with #ifdef
This would break CONFIG_CMD_IMPORTENV into smaller pieces.
#ifdef wouldn't look too bad around the code, only the inline string changes
would be ugly.

What would you recommend?

>
> > I've also compared the resulting u-boot.bin binary size with and without
> > the patch and the difference is about 40 bytes.
>
> Yes, but it's 40 bytes on nearly every single platform.
>
> --
> Tom

Kind regards,
Luka