linux-kernel - Re: [PATCH] mtd: nand: raw: qcom_nandc: Don't clear_bam

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Message-ID: <0a8d6550-aa19-0af1-abae-66bf34c91ea8@somainline.org>
Date:   Mon, 31 Jan 2022 11:09:54 +0100
From:   Konrad Dybcio <konrad.dybcio@...ainline.org>
To:     Sricharan Ramabadhran <sricharan@...eaurora.org>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Manivannan Sadhasivam <mani@...nel.org>
Cc:     ~postmarketos/upstreaming@...ts.sr.ht, martin.botka@...ainline.org,
        angelogioacchino.delregno@...ainline.org,
        marijn.suijten@...ainline.org, jamipkettunen@...ainline.org,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        linux-mtd@...ts.infradead.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org, mdalam@...eaurora.org
Subject: Re: [PATCH] mtd: nand: raw: qcom_nandc: Don't clear_bam_transaction
 on READID


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@...nel.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@...tlin.com wrote on Fri, 14 Jan 2022 08:27:18 +0100:
>>>>>> Hi Konrad,
>>>>>>
>>>>>> konrad.dybcio@...ainline.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@...ainline.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.


Konrad

>
>   Regards,
>       Sricharan
>