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

Huang Shijie
2011-07-20T10:34:26Z

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Hi,
>>>>>>> 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.
> For me, the bug always happens right away. So, if you need logs or debug
> output or can give me a pointer into some direction, I am glad to
> assist.
>
Thanks a lot. :)

I am trying to merge the two DMA descriptors into one in the send_command().
The original bsp code used only one DMA descriptor.

Huang Shijie
>
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