Am 14.08.2014 22:08, schrieb Stephen Warren:
On 08/14/2014 01:59 PM, Alexander Holler wrote:
Am 14.08.2014 21:51, schrieb Stephen Warren:
On 08/14/2014 01:38 PM, Alexander Holler wrote:
Am 14.08.2014 17:49, schrieb Stephen Warren:
On 08/14/2014 02:25 AM, Alexander Holler wrote:
As I've just remembered where I did see your name before, the config
for
the rpi (as found in 2004.04) misses the uenvcmd. That's necessary to
execute commands when using uEnv.txt.
It's easily done with something like the following:
"env import -t -r $loadaddr
$filesize;" \
"if test -n \"$uenvcmd\"; then " \
"echo \"Running uenvcmd
...\";" \
"run uenvcmd;" \
"fi;" \
My intention was that uEnv.txt be used to set up environment
variables,
not to allow its use for custom scripts.
Sure. In most cases changing the predefined available variables is
enough. But it's a very hand option if someone wants or needs to do
stuff which can't be done by just changing some environment variables
(one never knows what ideas people will have).
For such presumably non-standard things, why can't the user simply edit
$bootcmd, and pre-pend whatever they want?
Depends on when the bootcmd will be constructed. Usually that is done
after having read uEnv.txt to include variables defined in uEnv.txt in
bootcmd. So whatever bootcmd one sets in uEnv.txt, it just will be
overwritten.
What would over-write bootcmd? None of the boards I've looked at
auto-generates bootcmd. bootargs perhaps (which is a string passed to
the kernel) but not bootargs (which is a U-Boot command sequence that
U-Boot executes automatically at boot).
If some board does auto-generate bootcmd, I'd suggest that it not. The
static bootcmd could execute some kind of user-(or uenv-)set variable
and/or the auto-generation of bootcmd could happen before uenv.txt was
pulled in, so that whatever was in uenv.txt would have ultimate "power".
Ah, yes. Sorry, I confused bootcmd with bootargs (I don't live in u-boot
and just fiddle once a year or such with it).
But overwriting bootcmd needs to read uEnv.txt in PREBOOT (or how it is
named). I originally have read uEnv.txt in the bootcmd itself, so
overwriting it didn't work. But I don't want to dive too deep into that
discussion, as I think it's up to the board-maintainers to write the
config however they want and seem to fit for there users. I've just
mentioned the uenvcmd, because it was the first, I've added to my u-boot
for the rpi (to have the same interface I use with my other boards). ;)
Regards,
Alexander Holler
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