Using reblob to load another blob from ram

[Stefan S. <st...@da...>]

Hello.

I'm not sure if i'm wrong here, because this is cvs-commit list and
not discussion.

I'm writing here becuase the lart ml seems to be broken for at least 3
weeks. BTW, lart ml archive and anon cvs access to blob cvs is broken,
too. So no really good starting point for hacking on blob.

OK, back to my main problem. I'm one of the developer behind the
http://openezx.org/ project. EZX is the name of the Motorola Linux
smartphone architecture based on pxa27x. On this phones they use blob
as bootloader. But we like to extend blob to choose the kernel to boot
and booting kernel from MicroSD/SD card. This would help us a lot in
kernel and userspace development because we don't need to touch the
pre-installed system.

In some small talk with Tim Riker on IRC he suggested me to load
the extended blob into ram and do a reblob. Sounds great, but=20
unfortunately i get it not working.

Some more words about the setup. Motorola had modified blob. After
some discussion i was able to get the source. You can find it here:

http://www.datenfreihafen.org/~stefan/EZX/a780-blob.tar.bz2

It based on blob-2.0.5-pre2 .

We are able to communicate with the bootloader over usb. Harald Welte
wrote some kind of bootloader client which is called boot_usb.

http://svn.gnumonks.org/trunk/a780/src/boot_usb/

It loads the code into ram, exactly to KERNEL_RAM_BASE, and afterwards
JUMP to it. This works fine for selfcompiled kernels. But it does not
work for the blob binary at the moment.

A compile of the modified blob source give me the the following
interesting binaries:

blob
blob-chain
blob-rest
blob-rest-elf32
blob-start
blob-start-chain
blob-start-chain-elf32
blob-start-elf32

I tried all of them load to KERNEL_RAM_BASE and also to BLOB_RAM_BASE
as defined inside the blob code.

If i load blob or blob-start-elf32 the display goes blank and thats
it. For blob-start at KERNEL_RAM_BASE it goes blank, too. On all the
other tests exactly nothing happens.

I just changed the version string displayed to confirm if i see the
new blob on the screen.

So perhaps anybody here can help me at this point. The most
interesting questions are the following:

- Is there some good doc about blob? I don't find anything.
- Which binary i had to use for reblob?
- Which place i had to load into ram? BLOB_RAM_BASE or
  KERNEL_RAM_BASE?
- Tim Riker mentoined there are flying some SD card patches around.
  Where can i find it?

regards
Stefan Schmidt