[E3-hacking] PBL and flash access on the E3

Jonathan McDowell noodles at earth.li
Wed Mar 29 14:11:26 BST 2006

On Tue, Mar 28, 2006 at 11:37:23PM +0100, David Given wrote:
> Hurrah! I have my shiny new E3 up and running, and am getting pblq
> back up to speed.


> Next thing is to try and get the flash code up and running; but I'm a
> little hesitant to play because I don't want to overwrite anything
> crucial and brick the device. *Is* there anything crucial in the NAND
> flash? I notice that the MTD partition table has a chunk marked
> 'Amstrad Block'.  Does it matter if I overwrite this? 

You can completely nuke the NAND flash and PBL will still run ok I
believe. The Amstrad Block is where the MEM and LDR blocks exist by
default. I've been thinking about what the final MTD layout will be and
I'm currently leaning towards something like:

kernel		2M
u-boot		256K
u-boot params	256K
LDR etc		512K
JFFS2 partition	29M

I'm not entirely sure if PBL will read a LDR block earlier than 4M into
flash; need to test that. And I seemed to be getting issues with the
tail end of flash, so I need to have a look and see if PBL writes
anything there that I might have to avoid. Aside from that does this
seem sane to people?

> Plus, am I right in that the e3's NAND flash pseudoaddress is
> 0x400000, instead of the e2's 0x8001000?

I /think/ so, but it's been a long time since I've used PBL to
read/write the NAND.

> I've also got Jonathon's prebuilt kernel running, which appears to work

Jonath*a*n. (I'm on a mission to educate the world about how to spell my

> nicely --- at least, it produces a palette-mangled penguin and vast
> numbers of error messages (in pink) as the JFFS driver fails miserably
> to find a JFFS filesystem on the flash. I need to try a filesystem on
> a compact flash device and see if that works. But it's definitely
> getting somewhere!

I've updated the prebuilt kernel to include the palette fixing patch and
also enable the internal modem.


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