Hello Wolfgang,
Am 02.11.2020 um 13:51 schrieb Wolfgang Denk:
Dear Heiko,
In message a80c8548-a8a5-fb98-f9e3-fc659c2bdfec@denx.de you wrote:
I enabled now ENV_APPEND on this board and
CONFIG_ENV_IS_NOWHERE CONFIG_ENV_IS_IN_SPI_FLASH
This gives me the creeps. I know this is not cause by anything in your patch, but anyway...
Apparently the meaning of CONFIG_ENV_IS_NOWHERE is nowhere documented :-(
env/Kconfig says:
config ENV_IS_NOWHERE bool "Environment is not stored" default y if !ENV_IS_IN_EEPROM && !ENV_IS_IN_EXT4 && \ !ENV_IS_IN_FAT && !ENV_IS_IN_FLASH && \ !ENV_IS_IN_MMC && !ENV_IS_IN_NAND && \ !ENV_IS_IN_NVRAM && !ENV_IS_IN_ONENAND && \ !ENV_IS_IN_REMOTE && !ENV_IS_IN_SPI_FLASH && \ !ENV_IS_IN_UBI help Define this if you don't want to or can't have an environment stored on a storage medium. In this case the environment will still exist while U-Boot is running, but once U-Boot exits it will not be stored. U-Boot will therefore always start up with a default environment.
But common sense says that "IS NOWHERE" means that there is no storage defined for the environment. I would expect, that Kconfig
Yes and use default one ...
does not even allow to enable any CONFIG_ENV_IS_IN_* when CONFIG_ENV_IS_NOWHERE is selected - these are logically exclusive.
Hmm...
May I suggest that:
- our Kconfig files are changed such that CONFIG_ENV_IS_NOWHERE and CONFIG_ENV_IS_IN_* are indeed exclusive, so that we adhere to the POLA [1] ?
Yes if we really want such a hard setting without having an environment!
Currently CONFIG_ENV_IS_NOWHERE is not that hard and means U-Boot has no Environment ... it means use the built in default environment...
- for cases like this one, where there actually _is_ some storage defined, but it shall be used in a non-standard way, a new CONFIG_ option gets created that expresses in it's name what it does?
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())
For example: - load first default environment (and you are correct ENV_IS_NOWHERE is here really a misleading name).
- load environment from SPI NOR ...
May we only should do a simple rename ?
ENV_IS_NOWHERE -> ENV_IS_IN_UBOOT (or ENV_IS_IN_DEFAULT) ?
If we really want a hard "there is no storage" switch (which really means there is *no* environment ... I do not even know, if U-boot works without!) we should introduce a new ENV_IS_IN_DEFAULT which loads the default environment...
(I do not like this, as all? boards have a default environment, so it is enabled for all? boards ... which makes it obsolete...)
better suggestions?
bye, Heiko
[1] https://en.wikipedia.org/wiki/Principle_of_least_astonishment
Thanks!
Best regards,
Wolfgang Denk