[PATCH 0/5] Add UFS support for SM8750

[Nitin Rawat]

On 2/10/2025 3:43 PM, Manivannan Sadhasivam wrote:
> + Can (for the MCQ query)
> 
> On Mon, Feb 10, 2025 at 10:39:04AM +0100, neil.armstrong at linaro.org wrote:
>> On 09/02/2025 16:21, Manivannan Sadhasivam wrote:
>>> On Fri, Feb 07, 2025 at 11:47:12PM +0100, Konrad Dybcio wrote:
>>>> On 13.01.2025 10:46 PM, Melody Olvera wrote:
>>>>> Add UFS support for SM8750 SoCs.
>>>>>
>>>>> Signed-off-by: Melody Olvera <quic_molvera at quicinc.com>
>>>>> ---
>>>>> Nitin Rawat (5):
>>>>>         dt-bindings: phy: qcom,sc8280xp-qmp-ufs-phy: Document the SM8750 QMP UFS PHY
>>>>>         phy: qcom-qmp-ufs: Add PHY Configuration support for SM8750
>>>>>         dt-bindings: ufs: qcom: Document the SM8750 UFS Controller
>>>>>         arm64: dts: qcom: sm8750: Add UFS nodes for SM8750 SoC
>>>>>         arm64: dts: qcom: sm8750: Add UFS nodes for SM8750 QRD and MTP boards
>>>>
>>>> You still need the same workaround 8550/8650 have in the UFS driver
>>>> (UFSHCD_QUIRK_BROKEN_LSDBS_CAP) for it to work reliably, or at least
>>>> that was the case for me on a 8750 QRD.
>>>>
>>>> Please check whether we can make that quirk apply based on ctrl
>>>> version or so, so that we don't have to keep growing the compatible
>>>> list in the driver.
>>>>
>>>
>>> That would be a bizarre. When I added the quirk, I was told that it would affect
>>> only SM8550 and SM8650 (this one I learned later). I'm not against applying the
>>> quirk based on UFSHC version if the bug is carried forward, but that would be an
>>> indication of bad design.
>>
>> Isn't 8750 capable of using MCQ now ? because this is the whole issue behind
>> this UFSHCD_QUIRK_BROKEN_LSDBS_CAP, it's supposed to use MCQ by default... but
>> we don't.
>>
>> Is there any news about that ? It's a clear regression against downstream, not
>> having MCQ makes the UFS driver struggle to reach high bandwidth when the system
>> is busy because we can't spread the load over all CPUs and we have only single
>> queue to submit requests.
>>
> 
> There are hardware issues on SM8550 and SM8650(?) for the MCQ feature.
> Apparently, Qcom carries the workaround in downstream, but I got tired of
> pushing them to upstream the fix(es).
> 
> Maybe Can Guo can share what is the latest update on this.
> 
> - Mani
> 

Hi Mani,

I have already replied to konrad mail earlier in this thread.

The LSDBS workaround is only applicable for SM8650 and SM8550.
SM8750 and onwards doesn't need this WA anymore as it is fixed in HW.

Regards,
Nitin