Re: [i.MX28 GPMI] problem overwriting all-0xff data in NAND

Huang Shijie
2011-07-20T02:18:26Z

Hi Wolfram:
>>>>> I am debugging the DMA bug now. and I will send it out when i fix it.
>>>>>
>>>> What sort of DMA bug?
>>>>
>>> The DMA may time-out. :(
>>>
>>> The DMA time-out may occur in two situations:
>>> [1] send a command DMA descriptor, see the nfc->send_command() function.
>>> [2] read the non-ecc data from nand, see the nfc->read_data() function.
>>>
>>> I don't know why. Maybe caused by the timing, or something else.
> I am confused. The send-command DMA timeout prevents any write for me.
> You guys surely would have noticed if you have been bitten as well. Does
> it depend on the NAND chip?
I think It does not depend on the NAND chip.
My test chip is Samsung K9G8G08U0M.
Sometimes, I can run a long time while there is no DMA timeout occurring;
Sometimes, the bug appears right away.

>> Maybe you are missing this patch:
>> http://lists.infradead.org/pipermail/linux-arm-kernel/2011-April/049105.html
>> I sent it in April, but apparently it has not been integrated in
>> mainline or the pengutronix git.
> Well, just resend them; might be worth trying Shawn's comment, too (if
> that reset is really needed). BTW they didn't help for my case :(
I also tested the patch. It did not work too.

Best Regards
Huang Shijie
> Regards,
>
> Wolfram
>