1. Patchew
  2. linux
  3. [PATCH V1 0/3] Add support to disable UFS LPM
  4. View patch

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

Nitin Rawat posted 3 patches 8 months ago
There is a newer version of this series
[PATCH V1 3/3] scsi: ufs: qcom: Add support to disable UFS LPM Feature
Posted by Nitin Rawat 8 months ago 
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;
+		hba->caps |= UFSHCD_CAP_AGGR_POWER_COLLAPSE;
+		hba->caps |= UFSHCD_CAP_RPM_AUTOSUSPEND;
+	}
 	ufs_qcom_set_host_caps(hba);
 }

--
2.48.1
Re: [PATCH V1 3/3] scsi: ufs: qcom: Add support to disable UFS LPM Feature
Posted by Peter Wang (王信友) 7 months, 3 weeks ago 
On Thu, 2025-04-17 at 18:16 +0530, Nitin Rawat wrote:
> 
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> 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?

Thanks.
Peter



> +               hba->caps |= UFSHCD_CAP_AGGR_POWER_COLLAPSE;
> +               hba->caps |= UFSHCD_CAP_RPM_AUTOSUSPEND;
> +       }
>         ufs_qcom_set_host_caps(hba);
>  }
> 
> --
> 2.48.1
>
Re: [PATCH V1 3/3] scsi: ufs: qcom: Add support to disable UFS LPM Feature
Posted by Nitin Rawat 7 months, 3 weeks ago 

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
>> you have verified the sender or the content.
>>
>>
>> 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
>>
>
Re: [PATCH V1 3/3] scsi: ufs: qcom: Add support to disable UFS LPM Feature
Posted by Rob Herring 7 months, 3 weeks ago 
On Thu, Apr 17, 2025 at 06:16:45PM +0530, Nitin Rawat wrote:
> 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;
> +		hba->caps |= UFSHCD_CAP_AGGR_POWER_COLLAPSE;
> +		hba->caps |= UFSHCD_CAP_RPM_AUTOSUSPEND;
> +	}

Doesn't RuntimePM already have userspace controls? And that's a Linux 
feature that shouldn't really be controlled by DT. I think this property 
should still to things defined by the UFS spec.

Rob
Re: [PATCH V1 3/3] scsi: ufs: qcom: Add support to disable UFS LPM Feature
Posted by Nitin Rawat 7 months, 3 weeks ago 

On 4/22/2025 6:15 PM, Rob Herring wrote:
> On Thu, Apr 17, 2025 at 06:16:45PM +0530, Nitin Rawat wrote:
>> 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;
>> +		hba->caps |= UFSHCD_CAP_AGGR_POWER_COLLAPSE;
>> +		hba->caps |= UFSHCD_CAP_RPM_AUTOSUSPEND;
>> +	}
> 
> Doesn't RuntimePM already have userspace controls? And that's a Linux
> feature that shouldn't really be controlled by DT. I think this property
> should still to things defined by the UFS spec.

Hi Rob,
Yes userspace has runtime PM control but by the time UFS driver probes 
completes and userspace is up, there are chances runtime PM may get 
kicked in.

Regards,
Nitin

> 
> Rob
Re: [PATCH V1 3/3] scsi: ufs: qcom: Add support to disable UFS LPM Feature
Posted by Rob Herring 7 months, 3 weeks ago 
On Wed, Apr 23, 2025 at 01:14:27AM +0530, Nitin Rawat wrote:
> 
> 
> On 4/22/2025 6:15 PM, Rob Herring wrote:
> > On Thu, Apr 17, 2025 at 06:16:45PM +0530, Nitin Rawat wrote:
> > > 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;
> > > +		hba->caps |= UFSHCD_CAP_AGGR_POWER_COLLAPSE;
> > > +		hba->caps |= UFSHCD_CAP_RPM_AUTOSUSPEND;
> > > +	}
> > 
> > Doesn't RuntimePM already have userspace controls? And that's a Linux
> > feature that shouldn't really be controlled by DT. I think this property
> > should still to things defined by the UFS spec.
> 
> Hi Rob,
> Yes userspace has runtime PM control but by the time UFS driver probes
> completes and userspace is up, there are chances runtime PM may get kicked
> in.

That sounds like a problem more than 1 device would have...

Rob
Re: [PATCH V1 3/3] scsi: ufs: qcom: Add support to disable UFS LPM Feature
Posted by Nitin Rawat 7 months, 3 weeks ago 

On 4/23/2025 7:26 PM, Rob Herring wrote:
> On Wed, Apr 23, 2025 at 01:14:27AM +0530, Nitin Rawat wrote:
>>
>>
>> On 4/22/2025 6:15 PM, Rob Herring wrote:
>>> On Thu, Apr 17, 2025 at 06:16:45PM +0530, Nitin Rawat wrote:
>>>> 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;
>>>> +		hba->caps |= UFSHCD_CAP_AGGR_POWER_COLLAPSE;
>>>> +		hba->caps |= UFSHCD_CAP_RPM_AUTOSUSPEND;
>>>> +	}
>>>
>>> Doesn't RuntimePM already have userspace controls? And that's a Linux
>>> feature that shouldn't really be controlled by DT. I think this property
>>> should still to things defined by the UFS spec.
>>
>> Hi Rob,
>> Yes userspace has runtime PM control but by the time UFS driver probes
>> completes and userspace is up, there are chances runtime PM may get kicked
>> in.
> 
> That sounds like a problem more than 1 device would have...

Yes, Rob, since there's a possibility that runtime suspend might be 
triggered for some devices before probe completes and userspace is up, 
IMO it's better to disable the runtime PM capability during 
initialization based on the device tree for specific FPGA platforms that 
don't support LPM.

What's your opinion on this?"

Regards,
Nitin



> 
> Rob

Patchew 2.1-devel-b67e4c2

© 2016 - 2025 Red Hat, Inc.