Re: [PATCH V1 3/3] scsi: ufs: qcom: Add support to disable UFS LPM Feature

[Nitin Rawat <quic_nitirawa@quicinc.com>]

On 4/23/2025 10:30 AM, Peter Wang (王信友) wrote:
> On Thu, 2025-04-17 at 18:16 +0530, Nitin Rawat wrote:
>>
>> External email : Please do not click links or open attachments until
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>>
>>
>> There are emulation FPGA platforms or other platforms where UFS low
>> power mode is either unsupported or power efficiency is not a
>> critical
>> requirement.
>>
>> Disable all low power mode UFS feature based on the "disable-lpm"
>> device
>> tree property parsed in platform driver.
>>
>> Signed-off-by: Nitin Rawat <quic_nitirawa@quicinc.com>
>> ---
>>   drivers/ufs/host/ufs-qcom.c | 15 ++++++++-------
>>   1 file changed, 8 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-
>> qcom.c
>> index 1b37449fbffc..1024edf36b68 100644
>> --- a/drivers/ufs/host/ufs-qcom.c
>> +++ b/drivers/ufs/host/ufs-qcom.c
>> @@ -1014,13 +1014,14 @@ static void ufs_qcom_set_host_caps(struct
>> ufs_hba *hba)
>>
>>   static void ufs_qcom_set_caps(struct ufs_hba *hba)
>>   {
>> -       hba->caps |= UFSHCD_CAP_CLK_GATING |
>> UFSHCD_CAP_HIBERN8_WITH_CLK_GATING;
>> -       hba->caps |= UFSHCD_CAP_CLK_SCALING |
>> UFSHCD_CAP_WB_WITH_CLK_SCALING;
>> -       hba->caps |= UFSHCD_CAP_AUTO_BKOPS_SUSPEND;
>> -       hba->caps |= UFSHCD_CAP_WB_EN;
>> -       hba->caps |= UFSHCD_CAP_AGGR_POWER_COLLAPSE;
>> -       hba->caps |= UFSHCD_CAP_RPM_AUTOSUSPEND;
>> -
>> +       if (!hba->disable_lpm) {
>> +               hba->caps |= UFSHCD_CAP_CLK_GATING |
>> UFSHCD_CAP_HIBERN8_WITH_CLK_GATING;
>> +               hba->caps |= UFSHCD_CAP_CLK_SCALING |
>> UFSHCD_CAP_WB_WITH_CLK_SCALING;
>> +               hba->caps |= UFSHCD_CAP_AUTO_BKOPS_SUSPEND;
>> +               hba->caps |= UFSHCD_CAP_WB_EN;
>>
> 
> Hi, Nitin,
> 
> If hba->disable_lpm is true, WB should enable?
> Normally, you don't care about low power, so why wouldn't you enable
> WB?
> 
Hi Peter,

Thanks for review. Agree with you.
I will update this in next patchset.

Regards,
Nitin


> Thanks.
> Peter
> 
> 
> 
>> +               hba->caps |= UFSHCD_CAP_AGGR_POWER_COLLAPSE;
>> +               hba->caps |= UFSHCD_CAP_RPM_AUTOSUSPEND;
>> +       }
>>          ufs_qcom_set_host_caps(hba);
>>   }
>>
>> --
>> 2.48.1
>>
>