[PATCH] mtd: nand: raw: qcom_nandc: Don't clear_bam_transaction on READID

[Sricharan Ramabadhran]

Hi Konrad,

On 1/31/2022 3:39 PM, Konrad Dybcio wrote:
>
> On 28/01/2022 18:50, Sricharan Ramabadhran wrote:
>> Hi Konrad,
>>
>> On 1/28/2022 9:55 AM, Sricharan Ramabadhran wrote:
>>> Hi Miquel,
>>>
>>> On 1/26/2022 4:12 PM, Miquel Raynal wrote:
>>>> Hi Mani,
>>>>
>>>> mani at kernel.org wrote on Wed, 26 Jan 2022 16:03:16 +0530:
>>>>
>>>>> On Wed, Jan 26, 2022 at 11:16:13AM +0100, Miquel Raynal wrote:
>>>>>> Hello,
>>>>>>
>>>>>> miquel.raynal at bootlin.com wrote on Fri, 14 Jan 2022 08:27:18 +0100:
>>>>>>> Hi Konrad,
>>>>>>>
>>>>>>> konrad.dybcio at somainline.org wrote on Thu, 13 Jan 2022 19:44:26 
>>>>>>> +0100:
>>>>>>>> While I have absolutely 0 idea why and how, running 
>>>>>>>> clear_bam_transaction
>>>>>>>> when READID is issued makes the DMA totally clog up and refuse 
>>>>>>>> to function
>>>>>>>> at all on mdm9607. In fact, it is so bad that all the data gets 
>>>>>>>> garbled
>>>>>>>> and after a short while in the nand probe flow, the CPU decides 
>>>>>>>> that
>>>>>>>> sepuku is the only option.
>>>>>>>>
>>>>>>>> Removing _READID from the if condition makes it work like a 
>>>>>>>> charm, I can
>>>>>>>> read data and mount partitions without a problem.
>>>>>>>>
>>>>>>>> Signed-off-by: Konrad Dybcio <konrad.dybcio at somainline.org>
>>>>>>>> ---
>>>>>>>> This is totally just an observation which took me an inhumane 
>>>>>>>> amount of
>>>>>>>> debug prints to find.. perhaps there's a better reason behind 
>>>>>>>> this, but
>>>>>>>> I can't seem to find any answers.. Therefore, this is a BIG RFC!
>>>>>>> I'm adding two people from codeaurora who worked a lot on this 
>>>>>>> driver.
>>>>>>> Hopefully they will have an idea :)
>>>>>> Sadre, I've spent a significant amount of time reviewing your 
>>>>>> patches,
>>>>>> now it's your turn to not take a month to answer to your peers
>>>>>> proposals.
>>>>>>
>>>>>> Please help reviewing this patch.
>>>>> Sorry. I was hoping that Qcom folks would chime in as I don't have 
>>>>> any idea
>>>>> about the mdm9607 platform. It could be that the mail server 
>>>>> migration from
>>>>> codeaurora to quicinc put a barrier here.
>>>>>
>>>>> Let me ping them internally.
>>>> Oh, ok, I didn't know. Thanks!
>>>
>>>    Sorry Miquel, somehow we did not get this email in our inbox.
>>>    Thanks to Mani for pinging us, we will test this up today and get 
>>> back.
>>>
>>       While we could not reproduce this issue on our ipq boards (do 
>> not have a mdm9607 right now) and
>>        issue does not look any obvious.
>>       can you please give the debug logs that you did for the above 
>> stage by stage ?
>
> I won't have access to the board for about two weeks, sorry.
>
> When I get to it, I'll surely try to send you the logs, though there
>
> wasn't much more than just something jumping to who-knows-where
>
> after clear_bam_transaction was called, resulting in values associated 
> with
>
> the NAND being all zeroed out in pr_err/_debug/etc.
>
>
     Ok sure. So was the READID command itself failing (or) the 
subsequent one ?
    We can check which parameter reset by the clear_bam_transaction is 
causing the
    failure.  Meanwhile, looping in Pradeep who has access to the board, 
so in a better
    position to debug.

Regards,
    Sricharan