Hello Wolfgang,
Am 02.11.2020 um 13:51 schrieb Wolfgang Denk:
Dear Heiko,
In message <a80c8548-a8a5-fb98-f9e3-fc659c2bd...@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:
1) 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...
2) 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
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-52 Fax: +49-8142-66989-80 Email: h...@denx.de
