[U-Boot] DNS323 (Orion5x) must double ORION5X_SZ_BOOTROM to access full flash

[Albert ARIBAUD]

Le 24/08/2010 07:21, Chris Moore a écrit :
> Hi Rogan,
>
> Le 23/08/2010 18:06, Rogan Dawes a écrit :
>> Doubling the value for ORION5X_SZ_BOOTROM allowed me to access the
>> additional sectors, but that makes me wonder what the reason for it is.
>>
>> I know that the flash chip is wired up strangely, but would that also
>> affect the window mappings? If that is the case, I just need to document
>> WHY the parameter is doubled, but if not, it would be good to understand
>> the real reason for the change.
>>
>
> I am (very rashly) stabbing in the dark here because I don't know much
> about U-Boot and I haven't followed your previous posts (hence this
> off-list reply).
>
> However if your device size is half the bus size (like an 8-bit device
> on a 16-bit bus) it would seem logical to have to double the window size.
>
> Cheers,
> Chris

Hi Chris, BTW. :)

Rogan,

Seeing as ORION5X_SZ_BOOTROM is only used as a byte address limit for 
window mapping, and device vs bus size govern the maximum amout in a 
single bus access but do not govern its addressing, I don't think device 
width is involved here.

I'd rather ask whether this could be a window alignment issue, i.e is 
the flash base address 8 MB aligned? Seems like it, because IIRC its 
base is FF800000, which is 8MB-aligned.

Can you still try the original u-boot? Does it allow reading the full 8 
MB? If so, can you do a 'md.l 0xF1020000 40' in it, and then in your own 
u-boot with ORION5X_SZ_BOOTROM set to 8MB then 16MB? These are the 
window mapping registers, and it will allow us to know what the CPU 
really thinks boot ROM looks like. Also dump F101046C, that's the boot 
device bus configuration, again in both U-boots.

Amicalement,
-- 
Albert.