On Wed, 6 Jul 2016, Måns Rullgård wrote:
"Robert P. J. Day" rpjday@crashcourse.ca writes:
On Wed, 6 Jul 2016, Måns Rullgård wrote:
"Robert P. J. Day" rpjday@crashcourse.ca writes:
p.s. how does the default environment get to the CONFIG_ENV_ADDR defined in the board header file? is that done automatically when u-boot starts to run and notices that there is no valid environment info at that address, and therefore copies it for you?
If the stored environment is invalid (e.g. uninitialised), the built-in default is used. Nothing is written until you issue a saveenv command. This saves a copy of the live environment to the configured location.
ah, that's the final bit of the puzzle i was looking for ... the first time a "saveenv" is done is when the configured location is examined and, if uninitialized, the env is copied there and is used from then on.
saveenv always writes whatever is in memory to the permanent location,
and by "permanent location", you mean CONFIG_ENV_ADDR as defined in the board definition file, yes?
overwriting anything that was previously there. On startup, u-boot checks if the saved environment is valid and uses it if it is. If
and, again, by "saved environment", i assume you mean what is at CONFIG_ENV_ADDR. it's all a matter of terminology -- switching back and forth can make things confusing.
not to be overly pedantic (too late!), but is there a preferred expression for the environment stored at CONFIG_ENV_ADDR? is it "permanent environment" or "saved environment" or what?
not, the defaults (as configured for the board) are used. Only the saveenv command writes anything to nonvolatile storage.
ok, i think i have a handle on this now, thanks.
rday