[U-Boot] [PATCH 1/4] Add option -r to env import to allow import of text files with CRLF as line endings

[Stephen Warren <swarren@wwwdotorg.org>]

On 08/14/2014 12:41 PM, Robert Nelson wrote:
> On Thu, Aug 14, 2014 at 10:49 AM, Stephen Warren <swarren@wwwdotorg.org> wrote:
>> On 08/14/2014 02:25 AM, Alexander Holler wrote:
>>>
>>> Am 31.07.2014 21:57, schrieb Stephen Warren:
>>>
>>>> Huh, I do see that now. I must have been looking at the content of
>>>> common/cmd_nvedit.c from the wrong branch, which didn't include that
>>>> patch. I could have sworn I checked git history too, but evidently not.
>>>> It is indeed clearly there right before the patches which use it. Sorry
>>>> for the noise.
>>>
>>>
>>> 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.
>
> The check for if uenvcmd is set then run uenvcmd syntax, should really
> be pushed into the distro default stuff.  As that syntax is used by
> default for a lot of different targets in u-boot.  Most users who deal
> with u-boot (even if they don't want to) seem to understand it.

I don't think this is anything to do with distro defaults.

Distro defaults are intended to provide a single common interface 
between the bootloader and Linux/... distro. As such, locating and 
loading extlinux.conf fits the bill there. The whole idea is that 
distros/OSs wouldn't have to know anything about the bootloader at all; 
command script formats, etc.

uenv.txt is the opposite; it's very U-Boot specific, and more about 
internal implementation details of U-Boot. In particular, I only see a 
use-case for uenv.txt on systems that have nowhere to store the U-Boot 
environment other than in some filesystem. That's the reason the RPi 
port loads uenv.txt, so the environment can be modified somehow. Perhaps 
there's an ENV_IS_IN_FAT that could be used instead on the Pi? For 
example, none of the Tegra boards use uEnv.txt since "saveenv" to flash 
works there.

So, perhaps I could see providing include/common_bootenv.h to make the 
definition you wrote above common between boards, but I certainly would 
not expect that opting in to distro defaults automatically added support 
for uEnv.txt.