[BUG] pxa3xx: wait time out when scanning for bb

[Miquel RAYNAL]

Hi Sean,

On Fri, 15 Dec 2017 19:56:27 +0100
Sean Nyekjær <sean.nyekjaer at prevas.dk> wrote:

> Hi Miquel
> 
> >I am very sorry for the delay but it took me some time to figure a
> >way to reproduce your situation until I started doing the exact
> >sequence I asked you to follow. It turns out there was a nasty error
> >in the parser so you could not observe the last blocks of your chip
> >because I messed up with high addresses.  
> 
> Fantastic always nice to be able to reproduce the issue. Glad to be
> able to help :-)
> 
> >
> >I updated the Github branch [1], can you rebase on top of it? I think
> >this time we should get something :)  
> 
> I just did a quick boot with the new commits, and the kernel is able
> to find the bbt table :-)

Good ! :-)

So with nand-ecc-mode = "none" + on-flash-bbt, there is no more issue,
right?

> 
> I also tried booting with ECC enabled and with that enabled the
> driver is unable to read the bbt and marked all blocks bad.

And if I understand correctly, if you remove nand-ecc-mode = "none" (or
set it to "hw"), the kernel fails to find the BBT, that is right?

As I was not expecting such a quick answer, I did push another patch
after sending my email that fixes an issue in mtdcore.c, please check
you have it (there are a few "fixup!" patches, and on top of them you
must find one which is a well-formatted patch about
mtd_check_oob_ops()).

I learned that today: to get a prompt while all blocks are bad, you can
add:

    chip->options |= NAND_SKIP_BBTSCAN;

Before nand_scan_tail().

If you can reach a prompt with the failing configuration and when you
will have the time, I will welcome a dump of the same area as before
so we will try to understand what is wrong now ! :)

Thank you,
Miquèl