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

[Miquel RAYNAL <miquel.raynal@free-electrons.com>]

Hi Sean,

+Boris (NAND maintainer).

> >> Yes, but i don't think the arbiter have any affect in the nand
> >> controller. Bit 12 in NDCR register is marked reserved in the
> >> datasheet.  
> > Be careful with that. I recently enabled 64-bit platforms featuring
> > this NAND controller. After hours of digging because it was not
> > working, I set this bit by adding this property like in any other
> > device tree and it worked. I am not telling that it will solve your
> > issue, mostly not, but this is something you should be careful
> > about.  
> I have tried with arbiter enabled, no different behaviour observed.

Ok.

> >>>> (I only see the timeouts if I remove the nand-on-flash-bbt)  
> >>> The nand-on-flash-bbt will read some of the last pages in you NAND
> >>> chip where a bad block table is supposed to be and derive from
> >>> that whether a block is bad or not. So this does only one read. I
> >>> guess you should have at least one timeout there?  
> >> Maybe, but the flash is fine we are running a rootfs in the NAND
> >> chip.  
> > So you can safely use the content of the NAND chip? Without any
> > timeout neither with reads nor writes? Can you try the mtd-utils
> > from [5]: nanddump/nandwrite or nandpagetest?
> >
> > Also, can you isolate the line that produces the timeouts?
> >
> > [5]http://www.linux-mtd.infradead.org/  
> Yes the NAND chip is working fine and stores our data.
> 
> It is the command NAND_CMD_READOOB that causes it to timeout.

Ok, I had a look at the nand_cmdfunc() function which is, I suppose,
the one that is in use (because you are using 2k pages) but I could
not see anything obvious. Is your setup special in some way?

Could you enable dynamic debug by adding "#define DEBUG" *before* all
#includes at the top of the pxa3xx_nand.c driver? It should display all
register accesses. Also, can you read the content of NDCR and NDSR when
it timeouts?

Thanks,
Miquèl