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List of environment vars?

Posted by shirsch 
List of environment vars?
October 31, 2010 09:51AM
Hi all, and thanks to Jeff for the fine work! I have been playing with my new Dockstar over the weekend and things are basically going well (running Debian squeeze). I do have a few questions:

- Where are the pertinent environment variables documented? I found some general references on u-boot, but it does not include things that I believe may be specific to the Dockstar class of devices, e.g. usb_rootfstype. I'm specifically interested in converting my root partition back to ext2 to avoid NAND wear from the journaling.

- I used Jeff's script "install_uboot_mtd0.sh" to setup the box. Just to be sure I understand: This is not using a "chained" loader and _does_ leave mtd3 available for my use? There is SO much outdated and semi-conflicting information floating around it's very hard to grasp the "big picture".

- Should I setup the machine-type variable on my Dockstar? What advantage does this give me for the basic debian squeeze kernel (if any)? Is there a run-down on how to install an updated kernel? I'm setup to cross-compile from my desktop machine (installed the arm cross-tools and verified that they will build u-boot - I assume that implies they'll build a kernel).

Thanks for any help and guidance.

Steve
Johannes
Re: List of environment vars?
October 31, 2010 12:10PM
Most of the environment variables are just used by scripts in other variables, i.e., their names are chosen freely by the person who writes the boot scripts (that's Jeff in this case, or, if you modify the scripts, you). You can tell these variables from variables that are used by internal functions and commands of the boot loader: Look for references to the variable name in the content of other variables. For example, the usb_rootfstype is referenced by the script in the usb_set_bootargs variable, where it is used as part of the parameter string which is passed to the kernel.

The U-Boot documentation is here: http://www.denx.de/wiki/U-Boot/Documentation

Jeff's boot loader overwrites the original boot loader in mtd0. If the old Pogoplug system is to be loaded, the boot loader in mtd0 chainloads the original boot loader from a backup in the Pogoplug filesystem. All other cases (USB, UBIFS in mtd3, rescue system in mtd1+mtd2) are handled by the boot loader in mtd0.
Re: List of environment vars?
October 31, 2010 12:25PM
Here is a list of the default environment settings that are configured when you use the uBoot installer. This is, of course, subject to change with future releases.

-- Jeff
Re: List of environment vars?
October 31, 2010 12:45PM
Jeff Wrote:
-------------------------------------------------------
> Here is a list of the default environment settings
> that are configured when you use the uBoot
> installer. This is, of course, subject to change
> with future releases.

Thanks! What about the issue of the machine type variable? Should I be setting this?
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