lör 2014-01-18 klockan 05:46 -0800 skrev Boris BREZILLON:
> Do you know which mode are used (X ECC strength / 512 or 1024 bytes ?)
> and
> when they are are selected (does it depend on the connected NAND
> chip ?) ?
It seems to blindly try some modes until something usable is found.
Varying both chip address size and ECC layout.
Sorry I do not have the exact details on the ECC modes used. Only
analyzed nand controller command traces of A13 BROM trying to load
boot0. The trace can be found at
https://github.com/hno/Allwinner-Info/blob/master/NAND/boot0/A13-brom
>
>
> > - boot0 code is stored only on the first ECC block of each
> page (1024
> > bytes + ecc bytes)
>
> No, it reads a whole page at a time in sequental mode
> (data,ecc,data,ecc,data,ecc,data,ecc...).
>
>
> Are you sure ?
> This thread says that only the first 1024 bytes of data (+ 96 bytes of
> ECC) of each page are used:
yes I am sure. There was no page access commands between the sectors,
only linear read of data,ecc,data,ecc.
> I'm not a big fan of this approach, because the real media is an MTD
> (NAND) device,
> not a block device.
Hit implementation acks this by not providing a block device.
> iirc there is an interface for dynamically selecting ECC mode
> and other
> parameers. Or maybe that's only u-boot mtd?
>
>
> Haven't found anything authorizing per partiton ECC config, though
> this could be an
> enhancement of the MTD framework.
u-boot have user selectable ecc scheme for some boards. I.e. omap3 based
ones.
other boards select based on NAND size etc.
Regards
Henrik
tis 2014-01-21 klockan 19:13 +0100 skrev Henrik Nordström:
> > Are you sure ?
> > This thread says that only the first 1024 bytes of data (+ 96 bytes of
> > ECC) of each page are used:
>
> yes I am sure. There was no page access commands between the sectors,
> only linear read of data,ecc,data,ecc.
Hmm.. but thinking back I am no longer so sure. Need to test this again
while verifying with logic probe what is going on.
Regards
Henrik