From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To: Bart Van Assche <bvanassche@acm.org>
Cc: vireshk@kernel.org, nm@ti.com, sboyd@kernel.org,
myungjoo.ham@samsung.com, kyungmin.park@samsung.com,
cw00.choi@samsung.com, andersson@kernel.org,
konrad.dybcio@linaro.org, robh+dt@kernel.org,
krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
jejb@linux.ibm.com, martin.petersen@oracle.com,
alim.akhtar@samsung.com, avri.altman@wdc.com,
linux-scsi@vger.kernel.org, linux-pm@vger.kernel.org,
linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
quic_asutoshd@quicinc.com, quic_cang@quicinc.com,
quic_nitirawa@quicinc.com, quic_narepall@quicinc.com,
quic_bhaskarv@quicinc.com, quic_richardp@quicinc.com,
quic_nguyenb@quicinc.com, quic_ziqichen@quicinc.com,
bmasney@redhat.com, krzysztof.kozlowski@linaro.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 00/15] UFS: Add OPP and interconnect support
Date: Thu, 20 Jul 2023 22:27:37 +0530 [thread overview]
Message-ID: <20230720165737.GG48270@thinkpad> (raw)
In-Reply-To: <e46f077f-4602-1882-bc14-e8df2a216773@acm.org>
On Thu, Jul 20, 2023 at 09:44:38AM -0700, Bart Van Assche wrote:
> On 7/19/23 22:40, Manivannan Sadhasivam wrote:
> > This series adds OPP (Operating Points) support to UFSHCD driver and
> > interconnect support to Qcom UFS driver.
> >
> > Motivation behind adding OPP support is to scale both clocks as well as
> > regulators/performance state dynamically. Currently, UFSHCD just scales
> > clock frequency during runtime with the help of "freq-table-hz" property
> > defined in devicetree. With the addition of OPP tables in devicetree (as
> > done for Qcom SDM845 and SM8250 SoCs in this series) UFSHCD can now scale
> > both clocks and performance state of power domain which helps in power
> > saving.
> >
> > For the addition of OPP support to UFSHCD, there are changes required to
> > the OPP framework and devfreq drivers which are also added in this series.
> >
> > Finally, interconnect support is added to Qcom UFS driver for scaling the
> > interconnect path dynamically. This is required to avoid boot crash in
> > recent SoCs and also to save power during runtime. More information is
> > available in patch 13/13.
>
> How much power can OPP save? I'm asking this since I'm wondering whether
> the power saved by OPP outweighs the complexity added by this patch series.
>
I haven't had a chance to do proper power measurements with this series due to
lack of access to tools. But it won't be optimal to run the clocks at high/low
frequencies without changing the associated regulator/power domain state.
Atleast on Qcom platforms, the clock frequencies are tied to RPMh (power
management entity) performance states for the peripherals. So both have to go
hand in hand. Till now, only UFS among the other peripherals is not doing it
right and hence this series.
- Mani
> Thanks,
>
> Bart.
--
மணிவண்ணன் சதாசிவம்
next prev parent reply other threads:[~2023-07-20 16:57 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-20 5:40 [PATCH v2 00/15] UFS: Add OPP and interconnect support Manivannan Sadhasivam
2023-07-20 5:40 ` [PATCH v2 01/15] dt-bindings: ufs: common: add OPP table Manivannan Sadhasivam
2023-07-20 5:40 ` [PATCH v2 02/15] dt-bindings: opp: Increase maxItems for opp-hz property Manivannan Sadhasivam
2023-07-24 15:51 ` Rob Herring
2023-07-25 4:11 ` Viresh Kumar
2023-07-20 5:40 ` [PATCH v2 03/15] arm64: dts: qcom: sdm845: Add missing RPMh power domain to GCC Manivannan Sadhasivam
2023-07-20 5:40 ` [PATCH v2 04/15] arm64: dts: qcom: sdm845: Fix the min frequency of "ice_core_clk" Manivannan Sadhasivam
2023-07-21 7:18 ` Viresh Kumar
2023-07-21 11:57 ` Manivannan Sadhasivam
2023-07-22 3:15 ` Bjorn Andersson
2023-07-24 5:48 ` Manivannan Sadhasivam
2023-07-20 5:40 ` [PATCH v2 05/15] arm64: dts: qcom: sdm845: Add OPP table support to UFSHC Manivannan Sadhasivam
2023-07-20 5:40 ` [PATCH v2 06/15] arm64: dts: qcom: sm8250: " Manivannan Sadhasivam
2023-07-20 5:40 ` [PATCH v2 07/15] OPP: Introduce dev_pm_opp_find_freq_{ceil/floor}_indexed() APIs Manivannan Sadhasivam
2023-07-20 5:40 ` [PATCH v2 08/15] OPP: Introduce dev_pm_opp_get_freq_indexed() API Manivannan Sadhasivam
2023-07-21 5:54 ` Dan Carpenter
2023-07-20 5:40 ` [PATCH v2 09/15] PM / devfreq: Switch to dev_pm_opp_find_freq_{ceil/floor}_indexed() APIs Manivannan Sadhasivam
2023-07-23 20:06 ` Chanwoo Choi
2023-07-24 5:46 ` Manivannan Sadhasivam
2023-07-24 21:57 ` Chanwoo Choi
2023-07-20 5:40 ` [PATCH v2 10/15] scsi: ufs: core: Add OPP support for scaling clocks and regulators Manivannan Sadhasivam
2023-07-20 5:40 ` [PATCH v2 11/15] scsi: ufs: host: Add support for parsing OPP Manivannan Sadhasivam
2023-07-20 21:32 ` kernel test robot
2023-07-20 23:26 ` kernel test robot
2023-07-20 5:40 ` [PATCH v2 12/15] arm64: dts: qcom: sdm845: Add interconnect paths to UFSHC Manivannan Sadhasivam
2023-07-20 5:40 ` [PATCH v2 13/15] arm64: dts: qcom: sm8250: " Manivannan Sadhasivam
2023-07-20 5:40 ` [PATCH v2 14/15] scsi: ufs: core: Add enums for UFS lanes Manivannan Sadhasivam
2023-07-20 5:41 ` [PATCH v2 15/15] scsi: ufs: qcom: Add support for scaling interconnects Manivannan Sadhasivam
2023-07-20 16:44 ` [PATCH v2 00/15] UFS: Add OPP and interconnect support Bart Van Assche
2023-07-20 16:57 ` Manivannan Sadhasivam [this message]
2023-07-21 9:42 ` Viresh Kumar
2023-07-21 11:54 ` Manivannan Sadhasivam
2023-07-24 7:52 ` Viresh Kumar
2023-07-22 5:17 ` (subset) " Bjorn Andersson
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