Re: [PATCH v2 2/3] env: Add single to redundant environment upgrade path

[Tom Rini <trini@konsulko.com>]

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On Tue, Dec 23, 2025 at 06:43:00PM +0100, Heinrich Schuchardt wrote:
> On 12/23/25 15:31, Marek Vasut wrote:
> > Add support for converting single-copy environment to redundant environment.
> > In case CRC checks on both redundant environment copies fail, try one more
> > CRC check on the primary environment copy and treat it as single environment.
> 
> Why would a CRC check suddenly succeed if it has failed before?
> 
> This needs some more explanation.
> 
> > If that check does pass, rewrite the single-copy environment into redundant
> > environment format, indicate the environment is valid, and import that as
> > usual primary copy of redundant environment. Follow up 'env save' will then
> > store two environment copies and the system will continue to operate as
> > regular redundant environment system.
> > 
> > Add test which validates this upgrade path. The test starts with spi.bin
> > which is pre-populated as single-copy environment and then upgrades that
> > environment to dual-copy environment.
> > 
> > Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> > ---
> > Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
> > Cc: Jerome Forissier <jerome.forissier@linaro.org>
> > Cc: Simon Glass <sjg@chromium.org>
> > Cc: Tom Rini <trini@konsulko.com>
> > Cc: u-boot@lists.denx.de
> > ---
> > V2: - Gate the option behind ENV_REDUNDANT_UPGRADE
> >      - Fix up mkenvimage path in env test
> > ---
> >   env/Kconfig               | 11 ++++++
> >   env/common.c              | 31 +++++++++++++++-
> >   test/py/tests/test_env.py | 74 +++++++++++++++++++++++++++++++++++++++
> >   3 files changed, 115 insertions(+), 1 deletion(-)
> > 
> > diff --git a/env/Kconfig b/env/Kconfig
> > index 4430669964c..b312f9b5324 100644
> > --- a/env/Kconfig
> > +++ b/env/Kconfig
> > @@ -489,6 +489,17 @@ config ENV_REDUNDANT
> >   	  which is used by env import/export commands which are independent of
> >   	  storing variables to redundant location on a non volatile device.
> > +config ENV_REDUNDANT_UPGRADE
> > +	bool "Enable single-copy to redundant environment upgrade support"
> > +	depends on ENV_REDUNDANT
> > +	help
> > +	  Normally, redundant environment is expected to always operate on
> > +	  two copies of the environment. However, hardware that may have
> > +	  originally shipped with single-copy environment can be upgraded
> 
> %s/with single-copy/with a single-copy/
> %s/can be/that can be/
> 
> > +	  to redundant environment without loss of existing environment
> > +	  content by correctly configuring the location of the redundant
> > +	  environment copy and by enabling this option.
> 
> Why do we have to make this an option?
> Shouldn't we always try to restore the environment?

Because the use case here is (I believe) converting a platform which had
non-redundant environment to a functional redundant environment. Without
making this optional we get size growth on platforms which enable
redundant env today (see v1).

-- 
Tom

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