[RFC PATCH 0/4] ufs: set power domain performance state when scaling gears

[RFC PATCH 0/4] ufs: set power domain performance state when scaling gears

[Krzysztof Kozlowski]

Hi,

This is a proof-of-concept/RFC for changing the performance state
of power rails when scaling gears.

So far I added it as a parallel method to scaling clocks, thus
freq-table-hz stays in DTS, however OPP table should be probably
replace freq-table-hz entirely.

Best regards,
Krzysztof

Krzysztof Kozlowski (4):
  dt-bindings: clock: qcom,gcc-sdm845: add parent power domain
  dt-bindings: ufs: common: allow OPP table
  arm64: dts: qcom: sdm845: control RPMHPD performance states with UFS
  ufs: set power domain performance state when scaling gears

 .../bindings/clock/qcom,gcc-sdm845.yaml       |  3 ++
 .../devicetree/bindings/ufs/ufs-common.yaml   |  4 ++
 arch/arm64/boot/dts/qcom/sdm845.dtsi          | 17 +++++++-
 drivers/scsi/ufs/ufshcd-pltfrm.c              |  6 +++
 drivers/scsi/ufs/ufshcd.c                     | 42 +++++++++++++++----
 drivers/scsi/ufs/ufshcd.h                     |  3 ++
 6 files changed, 65 insertions(+), 10 deletions(-)

-- 
2.32.0

[RFC PATCH 1/4] dt-bindings: clock: qcom,gcc-sdm845: add parent power domain

[Krzysztof Kozlowski]

Allow Qualcomm GCC to register its parent power domain (e.g. RPMHPD) to
properly pass performance state from children.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 Documentation/devicetree/bindings/clock/qcom,gcc-sdm845.yaml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/clock/qcom,gcc-sdm845.yaml b/Documentation/devicetree/bindings/clock/qcom,gcc-sdm845.yaml
index d902f137ab17..5fe1b2c42d5a 100644
--- a/Documentation/devicetree/bindings/clock/qcom,gcc-sdm845.yaml
+++ b/Documentation/devicetree/bindings/clock/qcom,gcc-sdm845.yaml
@@ -43,6 +43,9 @@ properties:
   '#reset-cells':
     const: 1
 
+  powert-domains:
+    maxItems: 1
+
   '#power-domain-cells':
     const: 1
 
-- 
2.32.0

[RFC PATCH 2/4] dt-bindings: ufs: common: allow OPP table

[Krzysztof Kozlowski]

Except scaling UFS and bus clocks, it's necessary to scale also the
voltages of regulators or power domain performance state levels.  Adding
Operating Performance Points table allows to adjust power domain
performance state, depending on the UFS clock speed.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 Documentation/devicetree/bindings/ufs/ufs-common.yaml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/ufs/ufs-common.yaml b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
index 47a4e9e1a775..ce767bfbf05a 100644
--- a/Documentation/devicetree/bindings/ufs/ufs-common.yaml
+++ b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
@@ -26,6 +26,9 @@ properties:
       array is "0" then it is assumed that the frequency is set by the parent
       clock or a fixed rate clock source.
 
+  operating-points-v2: true
+  opp-table: true
+
   interrupts:
     maxItems: 1
 
@@ -75,6 +78,7 @@ properties:
 
 dependencies:
   freq-table-hz: [ 'clocks' ]
+  operating-points-v2: [ 'freq-table-hz' ]
 
 required:
   - interrupts
-- 
2.32.0

[RFC PATCH 3/4] arm64: dts: qcom: sdm845: control RPMHPD performance states with UFS

[Krzysztof Kozlowski]

UFS, when scaling gears, should choose appropriate performance state of
RPMHPD power domain controller.  Since UFS belongs to UFS_PHY_GDSC power
domain, add necessary parent power domain to GCC.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 arch/arm64/boot/dts/qcom/sdm845.dtsi | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/qcom/sdm845.dtsi b/arch/arm64/boot/dts/qcom/sdm845.dtsi
index b31bf62e8680..c999b41c2605 100644
--- a/arch/arm64/boot/dts/qcom/sdm845.dtsi
+++ b/arch/arm64/boot/dts/qcom/sdm845.dtsi
@@ -1078,6 +1078,7 @@ gcc: clock-controller@100000 {
 			#clock-cells = <1>;
 			#reset-cells = <1>;
 			#power-domain-cells = <1>;
+			power-domains = <&rpmhpd SDM845_CX>;
 		};
 
 		qfprom@784000 {
@@ -2336,8 +2337,22 @@ ufs_mem_hc: ufshc@1d84000 {
 				<0 0>,
 				<0 0>,
 				<0 300000000>;
-
+			operating-points-v2 = <&ufs_opp_table>;
 			status = "disabled";
+
+			ufs_opp_table: opp-table {
+				compatible = "operating-points-v2";
+
+				opp-50000000 {
+					opp-hz = /bits/ 64 <50000000>;
+					required-opps = <&rpmhpd_opp_svs>;
+				};
+
+				opp-200000000 {
+					opp-hz = /bits/ 64 <200000000>;
+					required-opps = <&rpmhpd_opp_nom>;
+				};
+			};
 		};
 
 		ufs_mem_phy: phy@1d87000 {
-- 
2.32.0

[RFC PATCH 4/4] ufs: set power domain performance state when scaling gears

[Krzysztof Kozlowski]

Scaling gears requires not only scaling clocks, but also voltage levels,
e.g. via performance states.

USe the provided OPP table, to set proper OPP frequency which through
required-opps will trigger performance state change.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 drivers/scsi/ufs/ufshcd-pltfrm.c |  6 +++++
 drivers/scsi/ufs/ufshcd.c        | 42 +++++++++++++++++++++++++-------
 drivers/scsi/ufs/ufshcd.h        |  3 +++
 3 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index cca4b2181a81..c8f19b54be92 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -360,6 +360,12 @@ int ufshcd_pltfrm_init(struct platform_device *pdev,
 		goto dealloc_host;
 	}
 
+	if (devm_pm_opp_of_add_table(dev))
+		dev_dbg(dev, "no OPP table (%d), no performance state control\n",
+			err);
+	else
+		hba->use_pm_opp = true;
+
 	ufshcd_init_lanes_per_dir(hba);
 
 	err = ufshcd_init(hba, mmio_base, irq);
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 3f9caafa91bf..84912db86da8 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1164,11 +1164,16 @@ static int ufshcd_wait_for_doorbell_clr(struct ufs_hba *hba,
 static int ufshcd_scale_gear(struct ufs_hba *hba, bool scale_up)
 {
 	int ret = 0;
+	struct ufs_clk_info *clki;
+	unsigned long pm_opp_target_rate;
 	struct ufs_pa_layer_attr new_pwr_info;
 
+	clki = list_first_entry(&hba->clk_list_head, struct ufs_clk_info, list);
+
 	if (scale_up) {
 		memcpy(&new_pwr_info, &hba->clk_scaling.saved_pwr_info.info,
 		       sizeof(struct ufs_pa_layer_attr));
+		pm_opp_target_rate = clki->max_freq;
 	} else {
 		memcpy(&new_pwr_info, &hba->pwr_info,
 		       sizeof(struct ufs_pa_layer_attr));
@@ -1184,6 +1189,13 @@ static int ufshcd_scale_gear(struct ufs_hba *hba, bool scale_up)
 			new_pwr_info.gear_tx = hba->clk_scaling.min_gear;
 			new_pwr_info.gear_rx = hba->clk_scaling.min_gear;
 		}
+		pm_opp_target_rate = clki->min_freq;
+	}
+
+	if (hba->use_pm_opp && scale_up) {
+		ret = dev_pm_opp_set_rate(hba->dev, pm_opp_target_rate);
+		if (ret)
+			return ret;
 	}
 
 	/* check if the power mode needs to be changed or not? */
@@ -1194,6 +1206,11 @@ static int ufshcd_scale_gear(struct ufs_hba *hba, bool scale_up)
 			hba->pwr_info.gear_tx, hba->pwr_info.gear_rx,
 			new_pwr_info.gear_tx, new_pwr_info.gear_rx);
 
+	if (ret && hba->use_pm_opp && scale_up)
+		dev_pm_opp_set_rate(hba->dev, hba->devfreq->previous_freq);
+	else if (hba->use_pm_opp && !scale_up)
+		ret = dev_pm_opp_set_rate(hba->dev, pm_opp_target_rate);
+
 	return ret;
 }
 
@@ -1435,9 +1452,11 @@ static int ufshcd_devfreq_init(struct ufs_hba *hba)
 	if (list_empty(clk_list))
 		return 0;
 
-	clki = list_first_entry(clk_list, struct ufs_clk_info, list);
-	dev_pm_opp_add(hba->dev, clki->min_freq, 0);
-	dev_pm_opp_add(hba->dev, clki->max_freq, 0);
+	if (!hba->use_pm_opp) {
+		clki = list_first_entry(clk_list, struct ufs_clk_info, list);
+		dev_pm_opp_add(hba->dev, clki->min_freq, 0);
+		dev_pm_opp_add(hba->dev, clki->max_freq, 0);
+	}
 
 	ufshcd_vops_config_scaling_param(hba, &hba->vps->devfreq_profile,
 					 &hba->vps->ondemand_data);
@@ -1449,8 +1468,10 @@ static int ufshcd_devfreq_init(struct ufs_hba *hba)
 		ret = PTR_ERR(devfreq);
 		dev_err(hba->dev, "Unable to register with devfreq %d\n", ret);
 
-		dev_pm_opp_remove(hba->dev, clki->min_freq);
-		dev_pm_opp_remove(hba->dev, clki->max_freq);
+		if (!hba->use_pm_opp) {
+			dev_pm_opp_remove(hba->dev, clki->min_freq);
+			dev_pm_opp_remove(hba->dev, clki->max_freq);
+		}
 		return ret;
 	}
 
@@ -1462,7 +1483,6 @@ static int ufshcd_devfreq_init(struct ufs_hba *hba)
 static void ufshcd_devfreq_remove(struct ufs_hba *hba)
 {
 	struct list_head *clk_list = &hba->clk_list_head;
-	struct ufs_clk_info *clki;
 
 	if (!hba->devfreq)
 		return;
@@ -1470,9 +1490,13 @@ static void ufshcd_devfreq_remove(struct ufs_hba *hba)
 	devfreq_remove_device(hba->devfreq);
 	hba->devfreq = NULL;
 
-	clki = list_first_entry(clk_list, struct ufs_clk_info, list);
-	dev_pm_opp_remove(hba->dev, clki->min_freq);
-	dev_pm_opp_remove(hba->dev, clki->max_freq);
+	if (!hba->use_pm_opp) {
+		struct ufs_clk_info *clki;
+
+		clki = list_first_entry(clk_list, struct ufs_clk_info, list);
+		dev_pm_opp_remove(hba->dev, clki->min_freq);
+		dev_pm_opp_remove(hba->dev, clki->max_freq);
+	}
 }
 
 static void __ufshcd_suspend_clkscaling(struct ufs_hba *hba)
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 88c20f3608c2..3bd02095897f 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -776,6 +776,8 @@ struct ufs_hba_monitor {
  * @auto_bkops_enabled: to track whether bkops is enabled in device
  * @vreg_info: UFS device voltage regulator information
  * @clk_list_head: UFS host controller clocks list node head
+ * @use_pm_opp: whether OPP table is provided and scaling gears should trigger
+ *              setting OPP
  * @pwr_info: holds current power mode
  * @max_pwr_info: keeps the device max valid pwm
  * @clk_scaling_lock: used to serialize device commands and clock scaling
@@ -894,6 +896,7 @@ struct ufs_hba {
 	bool auto_bkops_enabled;
 	struct ufs_vreg_info vreg_info;
 	struct list_head clk_list_head;
+	bool use_pm_opp;
 
 	/* Number of requests aborts */
 	int req_abort_count;
-- 
2.32.0

Re: [RFC PATCH 4/4] ufs: set power domain performance state when scaling gears

[Bjorn Andersson]

On Fri 01 Apr 07:58 PDT 2022, Krzysztof Kozlowski wrote:

> Scaling gears requires not only scaling clocks, but also voltage levels,
> e.g. via performance states.
> 
> USe the provided OPP table, to set proper OPP frequency which through
> required-opps will trigger performance state change.
> 

This looks quite nice! Just two questions about the path looking forward.

If we where to extend the opp core to allow specifying the clock rate
for some N first clocks (similar to how e.g. regulators are handled) it
seems possible to extend this to replace the freq-table property as
well. Would you agree?


The other missing required feature (in this area) from the upstream UFS
driver is the ability of voting for interconnect bandwidth. Based on
your path it would be trivial to specify different values for the votes
for each speed, but looking at downstream [1] (each row represents the
vote for the two paths in KB/s) indicates a more complex relationship
between gear and voted bandwidth.

This was the reason I suggested that perhaps we need to key the
opp-table based on the gear? But I don't think there would be any issue
detecting this in runtime...

[1] https://github.com/MiCode/kernel_devicetree/blob/zeus-s-oss/qcom/waipio.dtsi#L1982

Regards,
Bjorn

> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> ---
>  drivers/scsi/ufs/ufshcd-pltfrm.c |  6 +++++
>  drivers/scsi/ufs/ufshcd.c        | 42 +++++++++++++++++++++++++-------
>  drivers/scsi/ufs/ufshcd.h        |  3 +++
>  3 files changed, 42 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
> index cca4b2181a81..c8f19b54be92 100644
> --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
> +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
> @@ -360,6 +360,12 @@ int ufshcd_pltfrm_init(struct platform_device *pdev,
>  		goto dealloc_host;
>  	}
>  
> +	if (devm_pm_opp_of_add_table(dev))
> +		dev_dbg(dev, "no OPP table (%d), no performance state control\n",
> +			err);
> +	else
> +		hba->use_pm_opp = true;
> +
>  	ufshcd_init_lanes_per_dir(hba);
>  
>  	err = ufshcd_init(hba, mmio_base, irq);
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 3f9caafa91bf..84912db86da8 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -1164,11 +1164,16 @@ static int ufshcd_wait_for_doorbell_clr(struct ufs_hba *hba,
>  static int ufshcd_scale_gear(struct ufs_hba *hba, bool scale_up)
>  {
>  	int ret = 0;
> +	struct ufs_clk_info *clki;
> +	unsigned long pm_opp_target_rate;
>  	struct ufs_pa_layer_attr new_pwr_info;
>  
> +	clki = list_first_entry(&hba->clk_list_head, struct ufs_clk_info, list);
> +
>  	if (scale_up) {
>  		memcpy(&new_pwr_info, &hba->clk_scaling.saved_pwr_info.info,
>  		       sizeof(struct ufs_pa_layer_attr));
> +		pm_opp_target_rate = clki->max_freq;
>  	} else {
>  		memcpy(&new_pwr_info, &hba->pwr_info,
>  		       sizeof(struct ufs_pa_layer_attr));
> @@ -1184,6 +1189,13 @@ static int ufshcd_scale_gear(struct ufs_hba *hba, bool scale_up)
>  			new_pwr_info.gear_tx = hba->clk_scaling.min_gear;
>  			new_pwr_info.gear_rx = hba->clk_scaling.min_gear;
>  		}
> +		pm_opp_target_rate = clki->min_freq;
> +	}
> +
> +	if (hba->use_pm_opp && scale_up) {
> +		ret = dev_pm_opp_set_rate(hba->dev, pm_opp_target_rate);
> +		if (ret)
> +			return ret;
>  	}
>  
>  	/* check if the power mode needs to be changed or not? */
> @@ -1194,6 +1206,11 @@ static int ufshcd_scale_gear(struct ufs_hba *hba, bool scale_up)
>  			hba->pwr_info.gear_tx, hba->pwr_info.gear_rx,
>  			new_pwr_info.gear_tx, new_pwr_info.gear_rx);
>  
> +	if (ret && hba->use_pm_opp && scale_up)
> +		dev_pm_opp_set_rate(hba->dev, hba->devfreq->previous_freq);
> +	else if (hba->use_pm_opp && !scale_up)
> +		ret = dev_pm_opp_set_rate(hba->dev, pm_opp_target_rate);
> +
>  	return ret;
>  }
>  
> @@ -1435,9 +1452,11 @@ static int ufshcd_devfreq_init(struct ufs_hba *hba)
>  	if (list_empty(clk_list))
>  		return 0;
>  
> -	clki = list_first_entry(clk_list, struct ufs_clk_info, list);
> -	dev_pm_opp_add(hba->dev, clki->min_freq, 0);
> -	dev_pm_opp_add(hba->dev, clki->max_freq, 0);
> +	if (!hba->use_pm_opp) {
> +		clki = list_first_entry(clk_list, struct ufs_clk_info, list);
> +		dev_pm_opp_add(hba->dev, clki->min_freq, 0);
> +		dev_pm_opp_add(hba->dev, clki->max_freq, 0);
> +	}
>  
>  	ufshcd_vops_config_scaling_param(hba, &hba->vps->devfreq_profile,
>  					 &hba->vps->ondemand_data);
> @@ -1449,8 +1468,10 @@ static int ufshcd_devfreq_init(struct ufs_hba *hba)
>  		ret = PTR_ERR(devfreq);
>  		dev_err(hba->dev, "Unable to register with devfreq %d\n", ret);
>  
> -		dev_pm_opp_remove(hba->dev, clki->min_freq);
> -		dev_pm_opp_remove(hba->dev, clki->max_freq);
> +		if (!hba->use_pm_opp) {
> +			dev_pm_opp_remove(hba->dev, clki->min_freq);
> +			dev_pm_opp_remove(hba->dev, clki->max_freq);
> +		}
>  		return ret;
>  	}
>  
> @@ -1462,7 +1483,6 @@ static int ufshcd_devfreq_init(struct ufs_hba *hba)
>  static void ufshcd_devfreq_remove(struct ufs_hba *hba)
>  {
>  	struct list_head *clk_list = &hba->clk_list_head;
> -	struct ufs_clk_info *clki;
>  
>  	if (!hba->devfreq)
>  		return;
> @@ -1470,9 +1490,13 @@ static void ufshcd_devfreq_remove(struct ufs_hba *hba)
>  	devfreq_remove_device(hba->devfreq);
>  	hba->devfreq = NULL;
>  
> -	clki = list_first_entry(clk_list, struct ufs_clk_info, list);
> -	dev_pm_opp_remove(hba->dev, clki->min_freq);
> -	dev_pm_opp_remove(hba->dev, clki->max_freq);
> +	if (!hba->use_pm_opp) {
> +		struct ufs_clk_info *clki;
> +
> +		clki = list_first_entry(clk_list, struct ufs_clk_info, list);
> +		dev_pm_opp_remove(hba->dev, clki->min_freq);
> +		dev_pm_opp_remove(hba->dev, clki->max_freq);
> +	}
>  }
>  
>  static void __ufshcd_suspend_clkscaling(struct ufs_hba *hba)
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> index 88c20f3608c2..3bd02095897f 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -776,6 +776,8 @@ struct ufs_hba_monitor {
>   * @auto_bkops_enabled: to track whether bkops is enabled in device
>   * @vreg_info: UFS device voltage regulator information
>   * @clk_list_head: UFS host controller clocks list node head
> + * @use_pm_opp: whether OPP table is provided and scaling gears should trigger
> + *              setting OPP
>   * @pwr_info: holds current power mode
>   * @max_pwr_info: keeps the device max valid pwm
>   * @clk_scaling_lock: used to serialize device commands and clock scaling
> @@ -894,6 +896,7 @@ struct ufs_hba {
>  	bool auto_bkops_enabled;
>  	struct ufs_vreg_info vreg_info;
>  	struct list_head clk_list_head;
> +	bool use_pm_opp;
>  
>  	/* Number of requests aborts */
>  	int req_abort_count;
> -- 
> 2.32.0
> 

Re: [RFC PATCH 1/4] dt-bindings: clock: qcom,gcc-sdm845: add parent power domain

[Krzysztof Kozlowski]

On 02/04/2022 01:24, Stephen Boyd wrote:
> Quoting Krzysztof Kozlowski (2022-04-01 07:58:17)
>> Allow Qualcomm GCC to register its parent power domain (e.g. RPMHPD) to
>> properly pass performance state from children.
>>
>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>> ---
>>  Documentation/devicetree/bindings/clock/qcom,gcc-sdm845.yaml | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/clock/qcom,gcc-sdm845.yaml b/Documentation/devicetree/bindings/clock/qcom,gcc-sdm845.yaml
>> index d902f137ab17..5fe1b2c42d5a 100644
>> --- a/Documentation/devicetree/bindings/clock/qcom,gcc-sdm845.yaml
>> +++ b/Documentation/devicetree/bindings/clock/qcom,gcc-sdm845.yaml
>> @@ -43,6 +43,9 @@ properties:
>>    '#reset-cells':
>>      const: 1
>>  
>> +  powert-domains:
> 
> s/powert/power/

Thanks. This actually points to the fact I did not test this bindings
change :(

Best regards,
Krzysztof

Re: [RFC PATCH 4/4] ufs: set power domain performance state when scaling gears

[Krzysztof Kozlowski]

On 01/04/2022 21:47, Bjorn Andersson wrote:
> On Fri 01 Apr 07:58 PDT 2022, Krzysztof Kozlowski wrote:
> 
>> Scaling gears requires not only scaling clocks, but also voltage levels,
>> e.g. via performance states.
>>
>> USe the provided OPP table, to set proper OPP frequency which through
>> required-opps will trigger performance state change.
>>
> 
> This looks quite nice! Just two questions about the path looking forward.
> 
> If we where to extend the opp core to allow specifying the clock rate
> for some N first clocks (similar to how e.g. regulators are handled) it
> seems possible to extend this to replace the freq-table property as
> well. Would you agree?

Yes, although that might be trickier. The frequency is a key. I'll take
a look whether it could be changed to multiple values like the voltage.

> 
> 
> The other missing required feature (in this area) from the upstream UFS
> driver is the ability of voting for interconnect bandwidth. Based on
> your path it would be trivial to specify different values for the votes
> for each speed, but looking at downstream [1] (each row represents the
> vote for the two paths in KB/s) indicates a more complex relationship
> between gear and voted bandwidth.
> 
> This was the reason I suggested that perhaps we need to key the
> opp-table based on the gear? But I don't think there would be any issue
> detecting this in runtime...
> 
> [1] https://github.com/MiCode/kernel_devicetree/blob/zeus-s-oss/qcom/waipio.dtsi#L1982

It should be doable with current bindings, assuming that gear is some
imaginary frequency. We have two interconnects for UFS (the DDR and CPU)
and OPP bindings allow to specify opp-peak-kBps and opp-avg-kBps for all
of interconnects. IOW, the opp-peak-kBps will have two values and
opp-avg-kBps as well.

What would be still missing is scaling clocks.

interconnects = <&ddr>, <&cpu>
interconnect-names = "ufs-ddr", "cpu-ufs";
opp-table {
  // gear 1 or some core clock frequency?
  opp-1 {
    opp-hz = /bits/ 64 <75000000>, <0>, <0>, <75000000> ....;
    opp-avg-kBps = <922 1000>;
    opp-peak-kBps = <0 0>;
    required-opps = <&rpmpd_opp_low_svs>;
  }
}

arch/arm64/boot/dts/qcom/sdm630.dtsi already uses it.

I think still the problem is scaling of multiple clocks, depending on
the gear.

Best regards,
Krzysztof

Re: [RFC PATCH 3/4] arm64: dts: qcom: sdm845: control RPMHPD performance states with UFS

[Dmitry Baryshkov]

On 01/04/2022 17:58, Krzysztof Kozlowski wrote:
> UFS, when scaling gears, should choose appropriate performance state of
> RPMHPD power domain controller.  Since UFS belongs to UFS_PHY_GDSC power
> domain, add necessary parent power domain to GCC.

This will cause all gcc GDSCs to be rooted in the CX. Are we sure that 
this is an expected (and correct) change?

> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> ---
>   arch/arm64/boot/dts/qcom/sdm845.dtsi | 17 ++++++++++++++++-
>   1 file changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/qcom/sdm845.dtsi b/arch/arm64/boot/dts/qcom/sdm845.dtsi
> index b31bf62e8680..c999b41c2605 100644
> --- a/arch/arm64/boot/dts/qcom/sdm845.dtsi
> +++ b/arch/arm64/boot/dts/qcom/sdm845.dtsi
> @@ -1078,6 +1078,7 @@ gcc: clock-controller@100000 {
>   			#clock-cells = <1>;
>   			#reset-cells = <1>;
>   			#power-domain-cells = <1>;
> +			power-domains = <&rpmhpd SDM845_CX>;
>   		};
>   
>   		qfprom@784000 {
> @@ -2336,8 +2337,22 @@ ufs_mem_hc: ufshc@1d84000 {
>   				<0 0>,
>   				<0 0>,
>   				<0 300000000>;
> -
> +			operating-points-v2 = <&ufs_opp_table>;
>   			status = "disabled";
> +
> +			ufs_opp_table: opp-table {
> +				compatible = "operating-points-v2";
> +
> +				opp-50000000 {
> +					opp-hz = /bits/ 64 <50000000>;
> +					required-opps = <&rpmhpd_opp_svs>;
> +				};
> +
> +				opp-200000000 {
> +					opp-hz = /bits/ 64 <200000000>;
> +					required-opps = <&rpmhpd_opp_nom>;
> +				};
> +			};
>   		};
>   
>   		ufs_mem_phy: phy@1d87000 {


-- 
With best wishes
Dmitry

Re: [RFC PATCH 2/4] dt-bindings: ufs: common: allow OPP table

[Rob Herring]

On Fri, 01 Apr 2022 16:58:18 +0200, Krzysztof Kozlowski wrote:
> Except scaling UFS and bus clocks, it's necessary to scale also the
> voltages of regulators or power domain performance state levels.  Adding
> Operating Performance Points table allows to adjust power domain
> performance state, depending on the UFS clock speed.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> ---
>  Documentation/devicetree/bindings/ufs/ufs-common.yaml | 4 ++++
>  1 file changed, 4 insertions(+)
> 

Reviewed-by: Rob Herring <robh@kernel.org>

Re: [RFC PATCH 3/4] arm64: dts: qcom: sdm845: control RPMHPD performance states with UFS

[Bjorn Andersson]

On Sun 03 Apr 17:02 PDT 2022, Dmitry Baryshkov wrote:

> On 01/04/2022 17:58, Krzysztof Kozlowski wrote:
> > UFS, when scaling gears, should choose appropriate performance state of
> > RPMHPD power domain controller.  Since UFS belongs to UFS_PHY_GDSC power
> > domain, add necessary parent power domain to GCC.
> 
> This will cause all gcc GDSCs to be rooted in the CX. Are we sure that this
> is an expected (and correct) change?
> 

Per the last part of Rajendra's reply in [1], this should be fine.
Naturally we might have to come up with some way to bind gdscs to one of
multiple power-domains if that changes.

[1] https://lore.kernel.org/all/5e572c50-d6fe-5a21-d09f-f11a072538c5@codeaurora.org/

Regards,
Bjorn

> > 
> > Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> > ---
> >   arch/arm64/boot/dts/qcom/sdm845.dtsi | 17 ++++++++++++++++-
> >   1 file changed, 16 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm64/boot/dts/qcom/sdm845.dtsi b/arch/arm64/boot/dts/qcom/sdm845.dtsi
> > index b31bf62e8680..c999b41c2605 100644
> > --- a/arch/arm64/boot/dts/qcom/sdm845.dtsi
> > +++ b/arch/arm64/boot/dts/qcom/sdm845.dtsi
> > @@ -1078,6 +1078,7 @@ gcc: clock-controller@100000 {
> >   			#clock-cells = <1>;
> >   			#reset-cells = <1>;
> >   			#power-domain-cells = <1>;
> > +			power-domains = <&rpmhpd SDM845_CX>;
> >   		};
> >   		qfprom@784000 {
> > @@ -2336,8 +2337,22 @@ ufs_mem_hc: ufshc@1d84000 {
> >   				<0 0>,
> >   				<0 0>,
> >   				<0 300000000>;
> > -
> > +			operating-points-v2 = <&ufs_opp_table>;
> >   			status = "disabled";
> > +
> > +			ufs_opp_table: opp-table {
> > +				compatible = "operating-points-v2";
> > +
> > +				opp-50000000 {
> > +					opp-hz = /bits/ 64 <50000000>;
> > +					required-opps = <&rpmhpd_opp_svs>;
> > +				};
> > +
> > +				opp-200000000 {
> > +					opp-hz = /bits/ 64 <200000000>;
> > +					required-opps = <&rpmhpd_opp_nom>;
> > +				};
> > +			};
> >   		};
> >   		ufs_mem_phy: phy@1d87000 {
> 
> 
> -- 
> With best wishes
> Dmitry