Re: [PATCH v1 0/5] Add snps,dis_u3_susphy_quirk for some QC targets

[Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>]

On 3/25/25 11:10 PM, Bjorn Andersson wrote:
> On Tue, Mar 25, 2025 at 05:31:28PM +0100, Konrad Dybcio wrote:
>> On 3/25/25 4:01 PM, Prashanth K wrote:
>>>
>>>
>>> On 25-03-25 08:11 pm, Konrad Dybcio wrote:
>>>> On 3/25/25 1:30 PM, Prashanth K wrote:
>>>>> During device mode initialization on certain QC targets, before the
>>>>> runstop bit is set, sometimes it's observed that the GEVNTADR{LO/HI}
>>>>> register write fails. As a result, GEVTADDR registers are still 0x0.
>>>>> Upon setting runstop bit, DWC3 controller attempts to write the new
>>>>> events to address 0x0, causing an SMMU fault and system crash. More
>>>>> info about the crash at [1].
>>>>>
>>>>> This was initially observed on SM8450 and later reported on few
>>>>> other targets as well. As suggested by Qualcomm HW team, clearing
>>>>> the GUSB3PIPECTL.SUSPHY bit resolves the issue by preventing register
>>>>> write failures. Address this by setting the snps,dis_u3_susphy_quirk
>>>>> to keep the GUSB3PIPECTL.SUSPHY bit cleared. This change was tested
>>>>> on multiple targets (SM8350, SM8450 QCS615 etc.) for over an year
>>>>> and hasn't exhibited any side effects.
>>>>>
>>>>> [1]: https://lore.kernel.org/all/fa94cbc9-e637-ba9b-8ec8-67c6955eca98@quicinc.com/
>>>>>
>>>>> Prashanth K (3):
>>>>>   arm64: dts: qcom: sm8150: Add snps,dis_u3_susphy_quirk
>>>>>   arm64: dts: qcom: sm8350: Add snps,dis_u3_susphy_quirk
>>>>>   arm64: dts: qcom: sm8450: Add snps,dis_u3_susphy_quirk
>>>>>
>>>>> Pratham Pratap (2):
>>>>>   arm64: dts: qcom: qcs615: Add snps,dis_u3_susphy_quirk
>>>>>   arm64: dts: qcom: qdu1000: Add snps,dis_u3_susphy_quirk
>>>>
>>>> Are there more targets affected, from the list of the ones currently
>>>> supported upstream?
>>>>
>>>> Konrad
>>>
>>> My initial plan was to add it for all the QC platforms, but wasn't
>>> confident enough about it. Because we have seen the issue only on these
>>> targets and hence tested only on these.
>>
>> Okay, let's proceed with these and in the meantime please query internally
>> whether it could be applicable to others too
>>
> 
> But if it applies to all qcom targets, wouldn't it make more sense to
> add the property in the qcom glue driver?

If we did that and the issue was ever fixed in future hw, we'd have to
either re-add this patchset again or invent a snps,*en*_u3_susphy_quirk

Konrad