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Date:   Tue, 28 Jul 2020 16:49:05 +0530
From:   sbhanu@codeaurora.org
To:     Matthias Kaehlcke <mka@chromium.org>
Cc:     adrian.hunter@intel.com, ulf.hansson@linaro.org,
        robh+dt@kernel.org, linux-mmc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        devicetree@vger.kernel.org, agross@kernel.org,
        bjorn.andersson@linaro.org, rnayak@codeaurora.org,
        Pradeep P V K <ppvk@codeaurora.org>,
        devicetree-owner@vger.kernel.org
Subject: Re: [PATCH V2] arm64: dts: qcom: sc7180: Add bandwidth votes for eMMC
 and SDcard
In-Reply-To: <20200727191029.GA3191083@google.com>
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 <20200724171018.GZ3191083@google.com>
 <7ffcb56e9e6723f4bae687e0f491cb93@codeaurora.org>
 <20200727191029.GA3191083@google.com>
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On 2020-07-28 00:40, Matthias Kaehlcke wrote:
> Hi,
> 
> On Mon, Jul 27, 2020 at 12:20:38PM +0530, sbhanu@codeaurora.org wrote:
>> On 2020-07-24 22:40, Matthias Kaehlcke wrote:
>> > Hi Shaik,
>> >
>> > On Tue, Jul 21, 2020 at 04:16:21PM +0530, Shaik Sajida Bhanu wrote:
>> > > From: Pradeep P V K <ppvk@codeaurora.org>
>> > >
>> > > Add the bandwidth domain supporting performance state and
>> > > the corresponding OPP tables for the sdhc device on sc7180.
>> > >
>> > > Signed-off-by: Pradeep P V K <ppvk@codeaurora.org>
>> > > Signed-off-by: Shaik Sajida Bhanu <sbhanu@codeaurora.org>
>> > > ---
>> > >
>> > > Changes since V1:
>> > > 	- Incorporated review comments by Bjorn Andersson.
>> > > ---
>> > >  arch/arm64/boot/dts/qcom/sc7180.dtsi | 15 +++++++++++++++
>> > >  1 file changed, 15 insertions(+)
>> > >
>> > > diff --git a/arch/arm64/boot/dts/qcom/sc7180.dtsi
>> > > b/arch/arm64/boot/dts/qcom/sc7180.dtsi
>> > > index 68f9894..d78a066 100644
>> > > --- a/arch/arm64/boot/dts/qcom/sc7180.dtsi
>> > > +++ b/arch/arm64/boot/dts/qcom/sc7180.dtsi
>> > > @@ -684,6 +684,9 @@
>> > >  			clocks = <&gcc GCC_SDCC1_APPS_CLK>,
>> > >  					<&gcc GCC_SDCC1_AHB_CLK>;
>> > >  			clock-names = "core", "iface";
>> > > +			interconnects = <&aggre1_noc MASTER_EMMC &mc_virt SLAVE_EBI1>,
>> > > +				<&gem_noc MASTER_APPSS_PROC &config_noc SLAVE_EMMC_CFG>;
>> > > +			interconnect-names = "sdhc-ddr","cpu-sdhc";
>> > >  			power-domains = <&rpmhpd SC7180_CX>;
>> > >  			operating-points-v2 = <&sdhc1_opp_table>;
>> > >
>> > > @@ -704,11 +707,15 @@
>> > >  				opp-100000000 {
>> > >  					opp-hz = /bits/ 64 <100000000>;
>> > >  					required-opps = <&rpmhpd_opp_low_svs>;
>> > > +					opp-peak-kBps = <100000 100000>;
>> > > +					opp-avg-kBps = <100000 50000>;
>> > >  				};
>> > >
>> > >  				opp-384000000 {
>> > >  					opp-hz = /bits/ 64 <384000000>;
>> > >  					required-opps = <&rpmhpd_opp_svs_l1>;
>> > > +					opp-peak-kBps = <600000 900000>;
>> > > +					opp-avg-kBps = <261438 300000>;
>> > >  				};
>> > >  			};
>> > >  		};
>> > > @@ -2476,6 +2483,10 @@
>> > >  			clocks = <&gcc GCC_SDCC2_APPS_CLK>,
>> > >  					<&gcc GCC_SDCC2_AHB_CLK>;
>> > >  			clock-names = "core", "iface";
>> > > +
>> > > +			interconnects = <&aggre1_noc MASTER_SDCC_2 &mc_virt SLAVE_EBI1>,
>> > > +				<&gem_noc MASTER_APPSS_PROC &config_noc	SLAVE_SDCC_2>;
>> > > +			interconnect-names = "sdhc-ddr","cpu-sdhc";
>> > >  			power-domains = <&rpmhpd SC7180_CX>;
>> > >  			operating-points-v2 = <&sdhc2_opp_table>;
>> > >
>> > > @@ -2489,11 +2500,15 @@
>> > >  				opp-100000000 {
>> > >  					opp-hz = /bits/ 64 <100000000>;
>> > >  					required-opps = <&rpmhpd_opp_low_svs>;
>> > > +					opp-peak-kBps = <160000 100000>;
>> > > +					opp-avg-kBps = <80000 50000>;
>> > >  				};
>> > >
>> > >  				opp-202000000 {
>> > >  					opp-hz = /bits/ 64 <202000000>;
>> > >  					required-opps = <&rpmhpd_opp_svs_l1>;
>> > > +					opp-peak-kBps = <200000	120000>;
>> > > +					opp-avg-kBps = <100000 60000>;
>> > >  				};
>> > >  			};
>> > >  		};
>> >
>> > Does the sdhci-msm driver actually have BW scaling support at this
>> > point?
>> >
>> 
>> yes
>> 
>> > There is commit 4ece9795be56 ("mmc: sdhci-msm: Add interconnect
>> > bandwidth scaling support"), whose commit message says "make sure
>> > interconnect driver is ready before handling interconnect scaling.".
>> >
>> > I haven't seen any patch adding the scaling support (supposedly by
>> > adding dev_pm_opp_set_bw() calls?). Did I miss it? If not it seems
>> > it would make sense to post it in a series together with this patch,
>> > as far as I can tell this patch alone does nothing in practical terms.
>> >
>> > grep sdhc /sys/kernel/debug/interconnect/interconnect_summary
>> >   8804000.sdhci                          0            0            0
>> >   7c4000.sdhci                           0            0            0
>> >   7c4000.sdhci                           0            0            0
>> >   8804000.sdhci                          0            0            0
>> >   ...
>> 
>> "mmc: sdhci-msm: Use OPP API to set clk/perf
>> state"(https://lkml.org/lkml/2020/4/8/425) and "mmc: sdhci-msm: Add
>> interconnect bandwidth scaling 
>> support"(https://lkml.org/lkml/2020/3/12/60)
>> with these two patches scaling will be supported for sdhci-msm driver.
> 
> Are you testing with exactly these patches or with the ones that landed
> upstream? At least the second one changed substantially
> 
>> the values  in  grep sdhc
>> /sys/kernel/debug/interconnect/interconnect_summary will be zero 
>> during
>> device is in suspend state...
> 
> Yes, I forgot to mention that I started MMC IO before looking at
> 'interconnect_summary'.
> 
>> and the values in  grep sdhc
>> /sys/kernel/debug/interconnect/interconnect_summary during device in 
>> resume
>> state will be like the following::
>> 
>> cicalhost / # cat /sys/kernel/debug/interconnect/interconnect_summary 
>> | grep
>> sdh
>>   8804000.sdhci                          0        60000       120000
>>   7c4000.sdhci                           0       300000       900000
>>   7c4000.sdhci                           0       300000       900000
>>   8804000.sdhci                          0        60000       120000
>>   8804000.sdhci                          0       100000       200000
>>   7c4000.sdhci                           0       261438       600000
>>   8804000.sdhci                          0        60000       120000
> 
> On my system the bandwidth is never set:
> 
> 3.590152] sdhci_msm 7c4000.sdhci: DBG: old/new frequencies (384000000
> Hz) are same, nothing to do
> https://elixir.bootlin.com/linux/v5.7.8/source/drivers/opp/core.c#L847
> 
> This happens every time, even after the bandwith is set to 0. The 
> problem
> seems to be that opp_table->clk doesn't change for target_freq = 0.
> 
> My system is based on v5.4, so it is possible that my kernel is missing 
> some
> relevant patch from upstream.
Hi matthias,

In order to aviod confusion this patch is continuation of the below 
patch::
"mmc: sdhci-msm: Add interconnect bandwidth scaling support" 
(https://lkml.org/lkml/2020/6/9/160).

Thanks,
sajida