[U-Boot] U-boot Config Parameters on Compact Flash

[Dach Miroslaw]

Dear Wolfgang,

Thank you very much for your hints. Now, I have got an idea how to continue.

Could you please direct me to some manual/"how to" to find out how to configure IDE 
access by means of the CONFIG_IDE_* . I have examined several header files in u-boot/include/configs
and it seems to be that CONFIG_ATA_* could be/should be used in conjunction with CONFIG_IDE_*?

Best Regards

Mirek


-----Original Message-----
From: Wolfgang Denk [mailto:wd at denx.de]
Sent: Fri 1/21/2011 2:08 PM
To: Dach Miroslaw
Cc: u-boot at lists.denx.de
Subject: Re: [U-Boot] U-boot Config Parameters on Compact Flash
 
Dear "Dach Miroslaw",

please always keep the mailing list on Cc:

In message <1B4F8000449511488D1A640DD6DECA350392A614 at MAILBOX0A.psi.ch> you wrote:
> 
> I am sorry bothering so much but this Compact Flash issues is the
> showstopper for my project.

If it's really urgent you should consider engaging commercial support.
This would probably be the fastet nd most reliable way to solve your
issue quickly.  As far as free community support is concerned, this is
all done on a voluntary base, and you might even run into the effects
described here:
http://catb.org/esr/faqs/smart-questions.html#urgent

> Please let me write what I understood from your idea. Please correct me
> if I am wrong.
> 
> In the include config file I should say 
> #define CONFIG_ENV_IS_NOWHERE
> meaning take the default environ configuration is built in the u-boot
> itself.

You should try and read some documentation to get a better
understanding of the terms.

CONFIG_* variables are compile-time settings.  They determine what
get's built into the U-Boot image running on your target.

This is different from envrionment variables, which can be loaded,
changed, and stored in the running system.

The only relation between the two is that you can use CONFIG_ settings
to define thedefault environment which gets used when no valid
environment can be found.

> Next, when the u-boot is booted the environment variables should be
> imported from Compact Flash.
> This is done in two steps:
> 1. ide read   (read the u-boot config from Compact Flash to RAM ?)
> 2. env import (import u-boot config from RAM to u-boot?)

Right.

> Could you please give me more hints which CONFIG macros should/could be
> used for the above mentioned steps.

This has nothing to do with any CONFIG_ settings.  Of Course I assume
that the "ide" command is enabled in your configuration so you can
access the CF card.

> Is there any command to import/export u-boot config.

Yes, as noted: "env import" and "env export".  Try "help env".

> So far I was using saveenv to export/save u-boot config into Flash? 

"saveenv" ist just an alias for "env save", whichis a somewhat
specialized version of "env export" (and which is not enabled in your
system when you define CONFIG_ENV_IS_NOWHERE).

Best regards,

Wolfgang Denk

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