[U-Boot] [PATCH v3 07/11] mtd: nand: add Faraday FTNANDC021 NAND controller support

Scott Wood
2013-04-29T20:46:17Z

On 04/28/2013 10:28:14 PM, Kuo-Jung Su wrote:
> 2013/4/27 Scott Wood <scottwood@freescale.com>:
> > Shouldn't .eccpos depend on HWECC?
> >
> >
>
> Actually it means nothing here, the ECC function is designed to be
> some kind of
> a blackbox to users (i.e softwares), the actual position of ECC codes
> are not documented
> in the datasheet, I have to dig it out from RTL which I do not have
> permission to access.

Maybe get rid of .eccpos altogether, and supply your own (much simpler)
hwecc read/write_page functions -- similar to what fsl_elbc_nand, which
also has transparent (but not hidden) ECC, does? This would also let
you get rid of hwctl/calculate/correct.

> > Is it really all in one step, regardless of page size?
> >
>
> Theoretical, NO.
> It uses R-S or BCH for Forwarding Error Correction, which is selected
> at RTL level.
> Which means it actually 522 bytes per step at RS and 528 bytes per
> step at BCH.
>
> However it's all blackbox to software, the FTNANDC021 simply supports
> only
> page read, so looks like everything is done at 1 step.

It would matter if you could detect correctable errors, but since you
can't, it doesn't.

-Scott