need some clarification on how environments work

[Robert P. J. Day]

On Wed, 8 Feb 2012, Sascha Hauer wrote:

... snip ...

> This is not the whole truth. CONFIG_DEFAULT_ENVIRONMENT_PATH can be
> a list of directories. All pathes in this list are copied into a
> temporary directory. This means that you can compose your
> environment out of different directories. This also means that you
> can overwrite files with more specific versions.

> If CONFIG_DEFAULT_ENVIRONMENT is enabled 'defaultenv' will be added
> to the start of the list. So defaultenv/ contains a 'config' files
> with FIXMEs. This is normally overwritten with the contents of your
> board specific config file in arch/<arch>/<board>/env/config.

  i think what is needed here is an agreement on *terminology*.  you
can't document anything properly unless you can *name* it.  so what
names should be used here?

  consider the file referred to above, whose name is *actually*
arch/<arch>/boards/<board>/env/config (correct?), an example being,
say, arch/arm/boards/panda/env/config.  what is the official name of
this "config" file?

  sascha called it the "board-specific config file"?  everyone good
with that?  it could just as easily be called the "board-specific
environment file".  whatever.  a couple questions about it.  first,
will there always be just one of them per board, and will it always be
named "config"?  i *think* so but i refuse to make any assumptions.

  and second, is it an error if a board has no such file?  currently,
the beagleboard has no such file.  is that an acceptable state of
affairs?  or is it something that should be resolved?  the
"freescale-mx23-evk" board directory also doesn't have one, and there
might be others.  so what should be done there?

  and i want to correct what sascha wrote above, when he wrote:

> If CONFIG_DEFAULT_ENVIRONMENT is enabled 'defaultenv' will be added
> to the start of the list. So defaultenv/ contains a 'config' files
> with FIXMEs.

  actually, here's that part of common/Makefile:

ifdef CONFIG_DEFAULT_ENVIRONMENT
$(obj)/startup.o: include/generated/barebox_default_env.h
$(obj)/env.o: include/generated/barebox_default_env.h

ifeq ($(CONFIG_DEFAULT_ENVIRONMENT_GENERIC),y)
DEFAULT_ENVIRONMENT_PATH = "defaultenv"
endif

  so it would appear to be CONFIG_DEFAULT_ENVIRONMENT_GENERIC that
dictates whether the file defaultenv/config is imported as part of the
environment.

  anyway, feel free to clarify all of this while i think up more
questions. :-)

rday

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
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