On 05/11/2020 17.40, Wolfgang Denk wrote:
Dear Rasmus,
In message 8ff3b8ad-8c4e-fe99-69c8-7c174e997a49@prevas.dk you wrote:
Not in a none standard way! Instead you can define more than one environment storage devices and load them in a board specific order (defined thorugh board specfif function env_get_location())
Yes, agreed. But this logically impossible if there is no storage at all, which is what CONFIG_ENV_IS_NOWHERE says.
Then should all the current config options CONFIG_ENV_IS_ be renamed to CONFIG_ENV_MAY_BE_? Because that's really what they mean.
This is not correct.
The CONFIG_ENV_IS_FOO means: if you use "env save", then U-Boot will write the config to external storage using the FOO storage device.
Wolfgang, you're wrong. What you're saying was once true, when the location was a "choice" in Kconfig, but it hasn't been that since fb69464eae. Nowadays one can select multiple possible backends, and only one of them will be used when doing "env save".
Later (208bd2b8), _NOWHERE was made non-mutually-exclusive with the real storage targets.
If you define CONFIG_ENV_IS_NOWHERE, I would for example expect that all "env save" related code is omitted as we will never need it.
I haven't checked, but that functionality does seem to exist - not depending on whether CONFIG_ENV_IS_NOWHERE is not selected, but whether any of the CONFIG_ENV_IS_<somehere> is. See the ENV_IS_IN_DEVICE logic in cmd/nvedit.c. So if you select CONFIG_ENV_IS_NOWHERE and not any of the others, I think the build works as you'd expect.
Rasmus