[PATCH v1 4/9] scsi: ufs: add option to change default UFS power management level

[PATCH v1 4/9] scsi: ufs: add option to change default UFS power management level

[Asutosh Das]

From: Subhash Jadavani <subhashj@codeaurora.org>

UFS device and link can be put in multiple different low power modes hence
UFS driver supports multiple different low power modes. By default UFS
driver selects the default (optimal) low power mode (which gives moderate
power savings and have relatively less enter and exit latencies) but
we might have to tune this default power mode for different chipset
platforms to meet the low power requirements/goals. Hence this patch
adds option to change default UFS low power mode (level).

Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
---
 .../devicetree/bindings/ufs/ufshcd-pltfrm.txt      | 11 ++++++++
 drivers/scsi/ufs/ufshcd-pltfrm.c                   | 14 +++++++++++
 drivers/scsi/ufs/ufshcd.c                          | 29 +++++++++++++++-------
 drivers/scsi/ufs/ufshcd.h                          |  4 +--
 4 files changed, 47 insertions(+), 11 deletions(-)

diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
index c39dfef..f564d9a 100644
--- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
+++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
@@ -38,6 +38,15 @@ Optional properties:
 			  defined or a value in the array is "0" then it is assumed
 			  that the frequency is set by the parent clock or a
 			  fixed rate clock source.
+- rpm-level		: UFS Runtime power management level. Following PM levels are supported:
+			  0 - Both UFS device and Link in active state (Highest power consumption)
+			  1 - UFS device in active state but Link in Hibern8 state
+			  2 - UFS device in Sleep state but Link in active state
+			  3 - UFS device in Sleep state and Link in hibern8 state (default PM level)
+			  4 - UFS device in Power-down state and Link in Hibern8 state
+			  5 - UFS device in Power-down state and Link in OFF state (Lowest power consumption)
+- spm-level		: UFS System power management level. Allowed PM levels are same as rpm-level.
+
 -lanes-per-direction	: number of lanes available per direction - either 1 or 2.
 			  Note that it is assume same number of lanes is used both
 			  directions at once. If not specified, default is 2 lanes per direction.
@@ -66,4 +75,6 @@ Example:
 		freq-table-hz = <100000000 200000000>, <0 0>, <0 0>;
 		phys = <&ufsphy1>;
 		phy-names = "ufsphy";
+		rpm-level = <3>;
+		spm-level = <5>;
 	};
diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index e82bde0..7dba799 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -221,6 +221,19 @@ static int ufshcd_parse_regulator_info(struct ufs_hba *hba)
 	return err;
 }
 
+static void ufshcd_parse_pm_levels(struct ufs_hba *hba)
+{
+	struct device *dev = hba->dev;
+	struct device_node *np = dev->of_node;
+
+	if (np) {
+		if (of_property_read_u32(np, "rpm-level", &hba->rpm_lvl))
+			hba->rpm_lvl = -1;
+		if (of_property_read_u32(np, "spm-level", &hba->spm_lvl))
+			hba->spm_lvl = -1;
+	}
+}
+
 #ifdef CONFIG_PM
 /**
  * ufshcd_pltfrm_suspend - suspend power management function
@@ -340,6 +353,7 @@ int ufshcd_pltfrm_init(struct platform_device *pdev,
 		goto dealloc_host;
 	}
 
+	ufshcd_parse_pm_levels(hba);
 	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
 
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index b03f3ea..e950204 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -192,6 +192,14 @@ struct ufs_pm_lvl_states ufs_pm_lvl_states[] = {
 	return UFS_PM_LVL_0;
 }
 
+static inline bool ufshcd_is_valid_pm_lvl(int lvl)
+{
+	if (lvl >= 0 && lvl < ARRAY_SIZE(ufs_pm_lvl_states))
+		return true;
+	else
+		return false;
+}
+
 static struct ufs_dev_fix ufs_fixups[] = {
 	/* UFS cards deviations table */
 	UFS_FIX(UFS_VENDOR_SAMSUNG, UFS_ANY_MODEL,
@@ -8051,16 +8059,19 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	}
 
 	/*
-	 * Set the default power management level for runtime and system PM.
-	 * Default power saving mode is to keep UFS link in Hibern8 state
-	 * and UFS device in sleep state.
+	 * If rpm_lvl and and spm_lvl are not already set to valid levels,
+	 * set the default power management level for UFS runtime and system
+	 * suspend. Default power saving mode selected is keeping UFS link in
+	 * Hibern8 state and UFS device in sleep state.
 	 */
-	hba->rpm_lvl = ufs_get_desired_pm_lvl_for_dev_link_state(
-						UFS_SLEEP_PWR_MODE,
-						UIC_LINK_HIBERN8_STATE);
-	hba->spm_lvl = ufs_get_desired_pm_lvl_for_dev_link_state(
-						UFS_SLEEP_PWR_MODE,
-						UIC_LINK_HIBERN8_STATE);
+	if (!ufshcd_is_valid_pm_lvl(hba->rpm_lvl))
+		hba->rpm_lvl = ufs_get_desired_pm_lvl_for_dev_link_state(
+							UFS_SLEEP_PWR_MODE,
+							UIC_LINK_HIBERN8_STATE);
+	if (!ufshcd_is_valid_pm_lvl(hba->spm_lvl))
+		hba->spm_lvl = ufs_get_desired_pm_lvl_for_dev_link_state(
+							UFS_SLEEP_PWR_MODE,
+							UIC_LINK_HIBERN8_STATE);
 
 	/* Set the default auto-hiberate idle timer value to 150 ms */
 	if (hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT) {
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index e996a08..a2e1d5c 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -526,9 +526,9 @@ struct ufs_hba {
 	enum ufs_dev_pwr_mode curr_dev_pwr_mode;
 	enum uic_link_state uic_link_state;
 	/* Desired UFS power management level during runtime PM */
-	enum ufs_pm_level rpm_lvl;
+	int rpm_lvl;
 	/* Desired UFS power management level during system PM */
-	enum ufs_pm_level spm_lvl;
+	int spm_lvl;
 	struct device_attribute rpm_lvl_attr;
 	struct device_attribute spm_lvl_attr;
 	int pm_op_in_progress;
-- 
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH v1 4/9] scsi: ufs: add option to change default UFS power management level

[Adrian Hunter]

On 06/07/18 15:30, Asutosh Das wrote:
> From: Subhash Jadavani <subhashj@codeaurora.org>
> 
> UFS device and link can be put in multiple different low power modes hence
> UFS driver supports multiple different low power modes. By default UFS
> driver selects the default (optimal) low power mode (which gives moderate
> power savings and have relatively less enter and exit latencies) but
> we might have to tune this default power mode for different chipset
> platforms to meet the low power requirements/goals. Hence this patch
> adds option to change default UFS low power mode (level).
> 
> Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
> Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
> Signed-off-by: Can Guo <cang@codeaurora.org>
> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
> ---
>  .../devicetree/bindings/ufs/ufshcd-pltfrm.txt      | 11 ++++++++
>  drivers/scsi/ufs/ufshcd-pltfrm.c                   | 14 +++++++++++
>  drivers/scsi/ufs/ufshcd.c                          | 29 +++++++++++++++-------
>  drivers/scsi/ufs/ufshcd.h                          |  4 +--
>  4 files changed, 47 insertions(+), 11 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> index c39dfef..f564d9a 100644
> --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> @@ -38,6 +38,15 @@ Optional properties:
>  			  defined or a value in the array is "0" then it is assumed
>  			  that the frequency is set by the parent clock or a
>  			  fixed rate clock source.
> +- rpm-level		: UFS Runtime power management level. Following PM levels are supported:
> +			  0 - Both UFS device and Link in active state (Highest power consumption)
> +			  1 - UFS device in active state but Link in Hibern8 state
> +			  2 - UFS device in Sleep state but Link in active state
> +			  3 - UFS device in Sleep state and Link in hibern8 state (default PM level)
> +			  4 - UFS device in Power-down state and Link in Hibern8 state
> +			  5 - UFS device in Power-down state and Link in OFF state (Lowest power consumption)
> +- spm-level		: UFS System power management level. Allowed PM levels are same as rpm-level.
> +
>  -lanes-per-direction	: number of lanes available per direction - either 1 or 2.
>  			  Note that it is assume same number of lanes is used both
>  			  directions at once. If not specified, default is 2 lanes per direction.
> @@ -66,4 +75,6 @@ Example:
>  		freq-table-hz = <100000000 200000000>, <0 0>, <0 0>;
>  		phys = <&ufsphy1>;
>  		phy-names = "ufsphy";
> +		rpm-level = <3>;
> +		spm-level = <5>;
>  	};
> diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
> index e82bde0..7dba799 100644
> --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
> +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
> @@ -221,6 +221,19 @@ static int ufshcd_parse_regulator_info(struct ufs_hba *hba)
>  	return err;
>  }
>  
> +static void ufshcd_parse_pm_levels(struct ufs_hba *hba)
> +{
> +	struct device *dev = hba->dev;
> +	struct device_node *np = dev->of_node;
> +
> +	if (np) {
> +		if (of_property_read_u32(np, "rpm-level", &hba->rpm_lvl))
> +			hba->rpm_lvl = -1;
> +		if (of_property_read_u32(np, "spm-level", &hba->spm_lvl))
> +			hba->spm_lvl = -1;

These are generically useful to all UFSHC drivers, so they should be
device_property_read_u32() and they should be read for all drivers not just
pltfrm i.e. move this code into ufshcd.c

> +	}
> +}
> +
>  #ifdef CONFIG_PM
>  /**
>   * ufshcd_pltfrm_suspend - suspend power management function
> @@ -340,6 +353,7 @@ int ufshcd_pltfrm_init(struct platform_device *pdev,
>  		goto dealloc_host;
>  	}
>  
> +	ufshcd_parse_pm_levels(hba);
>  	pm_runtime_set_active(&pdev->dev);
>  	pm_runtime_enable(&pdev->dev);
>  
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index b03f3ea..e950204 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -192,6 +192,14 @@ struct ufs_pm_lvl_states ufs_pm_lvl_states[] = {
>  	return UFS_PM_LVL_0;
>  }
>  
> +static inline bool ufshcd_is_valid_pm_lvl(int lvl)
> +{
> +	if (lvl >= 0 && lvl < ARRAY_SIZE(ufs_pm_lvl_states))
> +		return true;
> +	else
> +		return false;
> +}
> +
>  static struct ufs_dev_fix ufs_fixups[] = {
>  	/* UFS cards deviations table */
>  	UFS_FIX(UFS_VENDOR_SAMSUNG, UFS_ANY_MODEL,
> @@ -8051,16 +8059,19 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
>  	}
>  
>  	/*
> -	 * Set the default power management level for runtime and system PM.
> -	 * Default power saving mode is to keep UFS link in Hibern8 state
> -	 * and UFS device in sleep state.
> +	 * If rpm_lvl and and spm_lvl are not already set to valid levels,
> +	 * set the default power management level for UFS runtime and system
> +	 * suspend. Default power saving mode selected is keeping UFS link in
> +	 * Hibern8 state and UFS device in sleep state.
>  	 */
> -	hba->rpm_lvl = ufs_get_desired_pm_lvl_for_dev_link_state(
> -						UFS_SLEEP_PWR_MODE,
> -						UIC_LINK_HIBERN8_STATE);
> -	hba->spm_lvl = ufs_get_desired_pm_lvl_for_dev_link_state(
> -						UFS_SLEEP_PWR_MODE,
> -						UIC_LINK_HIBERN8_STATE);
> +	if (!ufshcd_is_valid_pm_lvl(hba->rpm_lvl))
> +		hba->rpm_lvl = ufs_get_desired_pm_lvl_for_dev_link_state(
> +							UFS_SLEEP_PWR_MODE,
> +							UIC_LINK_HIBERN8_STATE);
> +	if (!ufshcd_is_valid_pm_lvl(hba->spm_lvl))
> +		hba->spm_lvl = ufs_get_desired_pm_lvl_for_dev_link_state(
> +							UFS_SLEEP_PWR_MODE,
> +							UIC_LINK_HIBERN8_STATE);
>  
>  	/* Set the default auto-hiberate idle timer value to 150 ms */
>  	if (hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT) {
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> index e996a08..a2e1d5c 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -526,9 +526,9 @@ struct ufs_hba {
>  	enum ufs_dev_pwr_mode curr_dev_pwr_mode;
>  	enum uic_link_state uic_link_state;
>  	/* Desired UFS power management level during runtime PM */
> -	enum ufs_pm_level rpm_lvl;
> +	int rpm_lvl;
>  	/* Desired UFS power management level during system PM */
> -	enum ufs_pm_level spm_lvl;
> +	int spm_lvl;
>  	struct device_attribute rpm_lvl_attr;
>  	struct device_attribute spm_lvl_attr;
>  	int pm_op_in_progress;
> 

Re: [PATCH v1 4/9] scsi: ufs: add option to change default UFS power management level

[Asutosh Das (asd)]

On 7/11/2018 4:20 PM, Adrian Hunter wrote:
> On 06/07/18 15:30, Asutosh Das wrote:
>> From: Subhash Jadavani <subhashj@codeaurora.org>
>>
>> UFS device and link can be put in multiple different low power modes hence
>> UFS driver supports multiple different low power modes. By default UFS
>> driver selects the default (optimal) low power mode (which gives moderate
>> power savings and have relatively less enter and exit latencies) but
>> we might have to tune this default power mode for different chipset
>> platforms to meet the low power requirements/goals. Hence this patch
>> adds option to change default UFS low power mode (level).
>>
>> Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
>> Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
>> Signed-off-by: Can Guo <cang@codeaurora.org>
>> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
>> ---
>>   .../devicetree/bindings/ufs/ufshcd-pltfrm.txt      | 11 ++++++++
>>   drivers/scsi/ufs/ufshcd-pltfrm.c                   | 14 +++++++++++
>>   drivers/scsi/ufs/ufshcd.c                          | 29 +++++++++++++++-------
>>   drivers/scsi/ufs/ufshcd.h                          |  4 +--
>>   4 files changed, 47 insertions(+), 11 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>> index c39dfef..f564d9a 100644
>> --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>> +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>> @@ -38,6 +38,15 @@ Optional properties:
>>   			  defined or a value in the array is "0" then it is assumed
>>   			  that the frequency is set by the parent clock or a
>>   			  fixed rate clock source.
>> +- rpm-level		: UFS Runtime power management level. Following PM levels are supported:
>> +			  0 - Both UFS device and Link in active state (Highest power consumption)
>> +			  1 - UFS device in active state but Link in Hibern8 state
>> +			  2 - UFS device in Sleep state but Link in active state
>> +			  3 - UFS device in Sleep state and Link in hibern8 state (default PM level)
>> +			  4 - UFS device in Power-down state and Link in Hibern8 state
>> +			  5 - UFS device in Power-down state and Link in OFF state (Lowest power consumption)
>> +- spm-level		: UFS System power management level. Allowed PM levels are same as rpm-level.
>> +
>>   -lanes-per-direction	: number of lanes available per direction - either 1 or 2.
>>   			  Note that it is assume same number of lanes is used both
>>   			  directions at once. If not specified, default is 2 lanes per direction.
>> @@ -66,4 +75,6 @@ Example:
>>   		freq-table-hz = <100000000 200000000>, <0 0>, <0 0>;
>>   		phys = <&ufsphy1>;
>>   		phy-names = "ufsphy";
>> +		rpm-level = <3>;
>> +		spm-level = <5>;
>>   	};
>> diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
>> index e82bde0..7dba799 100644
>> --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
>> +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
>> @@ -221,6 +221,19 @@ static int ufshcd_parse_regulator_info(struct ufs_hba *hba)
>>   	return err;
>>   }
>>   
>> +static void ufshcd_parse_pm_levels(struct ufs_hba *hba)
>> +{
>> +	struct device *dev = hba->dev;
>> +	struct device_node *np = dev->of_node;
>> +
>> +	if (np) {
>> +		if (of_property_read_u32(np, "rpm-level", &hba->rpm_lvl))
>> +			hba->rpm_lvl = -1;
>> +		if (of_property_read_u32(np, "spm-level", &hba->spm_lvl))
>> +			hba->spm_lvl = -1;
> 
> These are generically useful to all UFSHC drivers, so they should be
> device_property_read_u32() and they should be read for all drivers not just
> pltfrm i.e. move this code into ufshcd.c
> 
>> +	}
>> +}
>> +
>>   #ifdef CONFIG_PM
>>   /**
>>    * ufshcd_pltfrm_suspend - suspend power management function
>> @@ -340,6 +353,7 @@ int ufshcd_pltfrm_init(struct platform_device *pdev,
>>   		goto dealloc_host;
>>   	}
>>   
>> +	ufshcd_parse_pm_levels(hba);
>>   	pm_runtime_set_active(&pdev->dev);
>>   	pm_runtime_enable(&pdev->dev);
>>   
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> index b03f3ea..e950204 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -192,6 +192,14 @@ struct ufs_pm_lvl_states ufs_pm_lvl_states[] = {
>>   	return UFS_PM_LVL_0;
>>   }
>>   
>> +static inline bool ufshcd_is_valid_pm_lvl(int lvl)
>> +{
>> +	if (lvl >= 0 && lvl < ARRAY_SIZE(ufs_pm_lvl_states))
>> +		return true;
>> +	else
>> +		return false;
>> +}
>> +
>>   static struct ufs_dev_fix ufs_fixups[] = {
>>   	/* UFS cards deviations table */
>>   	UFS_FIX(UFS_VENDOR_SAMSUNG, UFS_ANY_MODEL,
>> @@ -8051,16 +8059,19 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
>>   	}
>>   
>>   	/*
>> -	 * Set the default power management level for runtime and system PM.
>> -	 * Default power saving mode is to keep UFS link in Hibern8 state
>> -	 * and UFS device in sleep state.
>> +	 * If rpm_lvl and and spm_lvl are not already set to valid levels,
>> +	 * set the default power management level for UFS runtime and system
>> +	 * suspend. Default power saving mode selected is keeping UFS link in
>> +	 * Hibern8 state and UFS device in sleep state.
>>   	 */
>> -	hba->rpm_lvl = ufs_get_desired_pm_lvl_for_dev_link_state(
>> -						UFS_SLEEP_PWR_MODE,
>> -						UIC_LINK_HIBERN8_STATE);
>> -	hba->spm_lvl = ufs_get_desired_pm_lvl_for_dev_link_state(
>> -						UFS_SLEEP_PWR_MODE,
>> -						UIC_LINK_HIBERN8_STATE);
>> +	if (!ufshcd_is_valid_pm_lvl(hba->rpm_lvl))
>> +		hba->rpm_lvl = ufs_get_desired_pm_lvl_for_dev_link_state(
>> +							UFS_SLEEP_PWR_MODE,
>> +							UIC_LINK_HIBERN8_STATE);
>> +	if (!ufshcd_is_valid_pm_lvl(hba->spm_lvl))
>> +		hba->spm_lvl = ufs_get_desired_pm_lvl_for_dev_link_state(
>> +							UFS_SLEEP_PWR_MODE,
>> +							UIC_LINK_HIBERN8_STATE);
>>   
>>   	/* Set the default auto-hiberate idle timer value to 150 ms */
>>   	if (hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT) {
>> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
>> index e996a08..a2e1d5c 100644
>> --- a/drivers/scsi/ufs/ufshcd.h
>> +++ b/drivers/scsi/ufs/ufshcd.h
>> @@ -526,9 +526,9 @@ struct ufs_hba {
>>   	enum ufs_dev_pwr_mode curr_dev_pwr_mode;
>>   	enum uic_link_state uic_link_state;
>>   	/* Desired UFS power management level during runtime PM */
>> -	enum ufs_pm_level rpm_lvl;
>> +	int rpm_lvl;
>>   	/* Desired UFS power management level during system PM */
>> -	enum ufs_pm_level spm_lvl;
>> +	int spm_lvl;
>>   	struct device_attribute rpm_lvl_attr;
>>   	struct device_attribute spm_lvl_attr;
>>   	int pm_op_in_progress;
>>
> 

Thanks. I'll make the changes and push it in v2.

-- 
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Re: [PATCH v1 4/9] scsi: ufs: add option to change default UFS power management level

[Rob Herring]

On Fri, Jul 06, 2018 at 06:00:31PM +0530, Asutosh Das wrote:
> From: Subhash Jadavani <subhashj@codeaurora.org>
> 
> UFS device and link can be put in multiple different low power modes hence
> UFS driver supports multiple different low power modes. By default UFS
> driver selects the default (optimal) low power mode (which gives moderate
> power savings and have relatively less enter and exit latencies) but
> we might have to tune this default power mode for different chipset
> platforms to meet the low power requirements/goals. Hence this patch
> adds option to change default UFS low power mode (level).
> 
> Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
> Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
> Signed-off-by: Can Guo <cang@codeaurora.org>
> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
> ---
>  .../devicetree/bindings/ufs/ufshcd-pltfrm.txt      | 11 ++++++++
>  drivers/scsi/ufs/ufshcd-pltfrm.c                   | 14 +++++++++++
>  drivers/scsi/ufs/ufshcd.c                          | 29 +++++++++++++++-------
>  drivers/scsi/ufs/ufshcd.h                          |  4 +--
>  4 files changed, 47 insertions(+), 11 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> index c39dfef..f564d9a 100644
> --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> @@ -38,6 +38,15 @@ Optional properties:
>  			  defined or a value in the array is "0" then it is assumed
>  			  that the frequency is set by the parent clock or a
>  			  fixed rate clock source.
> +- rpm-level		: UFS Runtime power management level. Following PM levels are supported:
> +			  0 - Both UFS device and Link in active state (Highest power consumption)
> +			  1 - UFS device in active state but Link in Hibern8 state
> +			  2 - UFS device in Sleep state but Link in active state
> +			  3 - UFS device in Sleep state and Link in hibern8 state (default PM level)
> +			  4 - UFS device in Power-down state and Link in Hibern8 state
> +			  5 - UFS device in Power-down state and Link in OFF state (Lowest power consumption)
> +- spm-level		: UFS System power management level. Allowed PM levels are same as rpm-level.

What's the default?

I assume these are minimums? The OS can pick higher power states. This 
seems to be a bit Linux specific (as 'runtime PM' could be considered 
Linux specific). For every other device, we don't put this type of 
information in DT, but is user controlled. So really, wouldn't 1 
property be sufficient for cases where a mode doesn't work due to 
some h/w limitation. Otherwise, it is an OS or user decision.

> +
>  -lanes-per-direction	: number of lanes available per direction - either 1 or 2.
>  			  Note that it is assume same number of lanes is used both
>  			  directions at once. If not specified, default is 2 lanes per direction.
> @@ -66,4 +75,6 @@ Example:
>  		freq-table-hz = <100000000 200000000>, <0 0>, <0 0>;
>  		phys = <&ufsphy1>;
>  		phy-names = "ufsphy";
> +		rpm-level = <3>;

Why specified if 3 is the default?

> +		spm-level = <5>;

These seem like sane defaults. When and why would you use some 
different?

Rob

Re: [PATCH v1 4/9] scsi: ufs: add option to change default UFS power management level

[Asutosh Das (asd)]

On 7/12/2018 2:03 AM, Rob Herring wrote:
> On Fri, Jul 06, 2018 at 06:00:31PM +0530, Asutosh Das wrote:
>> From: Subhash Jadavani <subhashj@codeaurora.org>
>>
>> UFS device and link can be put in multiple different low power modes hence
>> UFS driver supports multiple different low power modes. By default UFS
>> driver selects the default (optimal) low power mode (which gives moderate
>> power savings and have relatively less enter and exit latencies) but
>> we might have to tune this default power mode for different chipset
>> platforms to meet the low power requirements/goals. Hence this patch
>> adds option to change default UFS low power mode (level).
>>
>> Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
>> Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
>> Signed-off-by: Can Guo <cang@codeaurora.org>
>> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
>> ---
>>   .../devicetree/bindings/ufs/ufshcd-pltfrm.txt      | 11 ++++++++
>>   drivers/scsi/ufs/ufshcd-pltfrm.c                   | 14 +++++++++++
>>   drivers/scsi/ufs/ufshcd.c                          | 29 +++++++++++++++-------
>>   drivers/scsi/ufs/ufshcd.h                          |  4 +--
>>   4 files changed, 47 insertions(+), 11 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>> index c39dfef..f564d9a 100644
>> --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>> +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>> @@ -38,6 +38,15 @@ Optional properties:
>>   			  defined or a value in the array is "0" then it is assumed
>>   			  that the frequency is set by the parent clock or a
>>   			  fixed rate clock source.
>> +- rpm-level		: UFS Runtime power management level. Following PM levels are supported:
>> +			  0 - Both UFS device and Link in active state (Highest power consumption)
>> +			  1 - UFS device in active state but Link in Hibern8 state
>> +			  2 - UFS device in Sleep state but Link in active state
>> +			  3 - UFS device in Sleep state and Link in hibern8 state (default PM level)
>> +			  4 - UFS device in Power-down state and Link in Hibern8 state
>> +			  5 - UFS device in Power-down state and Link in OFF state (Lowest power consumption)
>> +- spm-level		: UFS System power management level. Allowed PM levels are same as rpm-level.
> 
> What's the default?
> 
> I assume these are minimums? The OS can pick higher power states. This
> seems to be a bit Linux specific (as 'runtime PM' could be considered
> Linux specific). For every other device, we don't put this type of
> information in DT, but is user controlled.
I didn't completely understand your comment.
Do you not want these properties to be in DT file?
When you say user-controlled, do you mean control it through sysfs entries?

> So really, wouldn't 1
> property be sufficient for cases where a mode doesn't work due to
> some h/w limitation. Otherwise, it is an OS or user decision.
I didn't completely understand this. Could you please elaborate on your 
intent here?

> 
>> +
>>   -lanes-per-direction	: number of lanes available per direction - either 1 or 2.
>>   			  Note that it is assume same number of lanes is used both
>>   			  directions at once. If not specified, default is 2 lanes per direction.
>> @@ -66,4 +75,6 @@ Example:
>>   		freq-table-hz = <100000000 200000000>, <0 0>, <0 0>;
>>   		phys = <&ufsphy1>;
>>   		phy-names = "ufsphy";
>> +		rpm-level = <3>;
> 
> Why specified if 3 is the default?
Ah yes - that should be removed.
I'll remove it in v2.

> 
>> +		spm-level = <5>;
> 
> These seem like sane defaults. When and why would you use some
> different?
I think each of the deeper sleep modes are associated with an increasing 
wakeup latency. For e.g. '0' would have the highest power-consumption 
and no resume latency at all as compared to '5'.
So depending on use-cases other modes may be chosen.

> 
> Rob
> 

-asd

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a 
Linux Foundation Collaborative Project

Re: [PATCH v1 4/9] scsi: ufs: add option to change default UFS power management level

[Rob Herring]

On Sun, Jul 22, 2018 at 9:20 PM Asutosh Das (asd)
<asutoshd@codeaurora.org> wrote:
>
> On 7/12/2018 2:03 AM, Rob Herring wrote:
> > On Fri, Jul 06, 2018 at 06:00:31PM +0530, Asutosh Das wrote:
> >> From: Subhash Jadavani <subhashj@codeaurora.org>
> >>
> >> UFS device and link can be put in multiple different low power modes hence
> >> UFS driver supports multiple different low power modes. By default UFS
> >> driver selects the default (optimal) low power mode (which gives moderate
> >> power savings and have relatively less enter and exit latencies) but
> >> we might have to tune this default power mode for different chipset
> >> platforms to meet the low power requirements/goals. Hence this patch
> >> adds option to change default UFS low power mode (level).
> >>
> >> Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
> >> Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
> >> Signed-off-by: Can Guo <cang@codeaurora.org>
> >> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
> >> ---
> >>   .../devicetree/bindings/ufs/ufshcd-pltfrm.txt      | 11 ++++++++
> >>   drivers/scsi/ufs/ufshcd-pltfrm.c                   | 14 +++++++++++
> >>   drivers/scsi/ufs/ufshcd.c                          | 29 +++++++++++++++-------
> >>   drivers/scsi/ufs/ufshcd.h                          |  4 +--
> >>   4 files changed, 47 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> >> index c39dfef..f564d9a 100644
> >> --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> >> +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
> >> @@ -38,6 +38,15 @@ Optional properties:
> >>                        defined or a value in the array is "0" then it is assumed
> >>                        that the frequency is set by the parent clock or a
> >>                        fixed rate clock source.
> >> +- rpm-level         : UFS Runtime power management level. Following PM levels are supported:
> >> +                      0 - Both UFS device and Link in active state (Highest power consumption)
> >> +                      1 - UFS device in active state but Link in Hibern8 state
> >> +                      2 - UFS device in Sleep state but Link in active state
> >> +                      3 - UFS device in Sleep state and Link in hibern8 state (default PM level)
> >> +                      4 - UFS device in Power-down state and Link in Hibern8 state
> >> +                      5 - UFS device in Power-down state and Link in OFF state (Lowest power consumption)
> >> +- spm-level         : UFS System power management level. Allowed PM levels are same as rpm-level.
> >
> > What's the default?
> >
> > I assume these are minimums? The OS can pick higher power states. This
> > seems to be a bit Linux specific (as 'runtime PM' could be considered
> > Linux specific). For every other device, we don't put this type of
> > information in DT, but is user controlled.
> I didn't completely understand your comment.
> Do you not want these properties to be in DT file?

Right, not if it is a user decision.

> When you say user-controlled, do you mean control it through sysfs entries?

Yes.

> > So really, wouldn't 1
> > property be sufficient for cases where a mode doesn't work due to
> > some h/w limitation. Otherwise, it is an OS or user decision.
> I didn't completely understand this. Could you please elaborate on your
> intent here?

The case that makes sense for this to be in DT is if there are h/w
limitations that prevent some low power modes. In such a case, that
limit is not likely specific to runtime PM or system suspend.

> >>   -lanes-per-direction       : number of lanes available per direction - either 1 or 2.
> >>                        Note that it is assume same number of lanes is used both
> >>                        directions at once. If not specified, default is 2 lanes per direction.
> >> @@ -66,4 +75,6 @@ Example:
> >>              freq-table-hz = <100000000 200000000>, <0 0>, <0 0>;
> >>              phys = <&ufsphy1>;
> >>              phy-names = "ufsphy";
> >> +            rpm-level = <3>;
> >
> > Why specified if 3 is the default?
> Ah yes - that should be removed.
> I'll remove it in v2.
>
> >
> >> +            spm-level = <5>;
> >
> > These seem like sane defaults. When and why would you use some
> > different?
> I think each of the deeper sleep modes are associated with an increasing
> wakeup latency. For e.g. '0' would have the highest power-consumption
> and no resume latency at all as compared to '5'.
> So depending on use-cases other modes may be chosen.

The use-case can change in a running system. For example if you are
plugged in, then you probably don't want to enter a lower power mode.

Rob

Re: [PATCH v1 4/9] scsi: ufs: add option to change default UFS power management level

[Asutosh Das (asd)]

On 7/23/2018 8:06 PM, Rob Herring wrote:
> On Sun, Jul 22, 2018 at 9:20 PM Asutosh Das (asd)
> <asutoshd@codeaurora.org> wrote:
>>
>> On 7/12/2018 2:03 AM, Rob Herring wrote:
>>> On Fri, Jul 06, 2018 at 06:00:31PM +0530, Asutosh Das wrote:
>>>> From: Subhash Jadavani <subhashj@codeaurora.org>
>>>>
>>>> UFS device and link can be put in multiple different low power modes hence
>>>> UFS driver supports multiple different low power modes. By default UFS
>>>> driver selects the default (optimal) low power mode (which gives moderate
>>>> power savings and have relatively less enter and exit latencies) but
>>>> we might have to tune this default power mode for different chipset
>>>> platforms to meet the low power requirements/goals. Hence this patch
>>>> adds option to change default UFS low power mode (level).
>>>>
>>>> Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
>>>> Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
>>>> Signed-off-by: Can Guo <cang@codeaurora.org>
>>>> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
>>>> ---
>>>>    .../devicetree/bindings/ufs/ufshcd-pltfrm.txt      | 11 ++++++++
>>>>    drivers/scsi/ufs/ufshcd-pltfrm.c                   | 14 +++++++++++
>>>>    drivers/scsi/ufs/ufshcd.c                          | 29 +++++++++++++++-------
>>>>    drivers/scsi/ufs/ufshcd.h                          |  4 +--
>>>>    4 files changed, 47 insertions(+), 11 deletions(-)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>>>> index c39dfef..f564d9a 100644
>>>> --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>>>> +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
>>>> @@ -38,6 +38,15 @@ Optional properties:
>>>>                         defined or a value in the array is "0" then it is assumed
>>>>                         that the frequency is set by the parent clock or a
>>>>                         fixed rate clock source.
>>>> +- rpm-level         : UFS Runtime power management level. Following PM levels are supported:
>>>> +                      0 - Both UFS device and Link in active state (Highest power consumption)
>>>> +                      1 - UFS device in active state but Link in Hibern8 state
>>>> +                      2 - UFS device in Sleep state but Link in active state
>>>> +                      3 - UFS device in Sleep state and Link in hibern8 state (default PM level)
>>>> +                      4 - UFS device in Power-down state and Link in Hibern8 state
>>>> +                      5 - UFS device in Power-down state and Link in OFF state (Lowest power consumption)
>>>> +- spm-level         : UFS System power management level. Allowed PM levels are same as rpm-level.
>>>
>>> What's the default?
>>>
>>> I assume these are minimums? The OS can pick higher power states. This
>>> seems to be a bit Linux specific (as 'runtime PM' could be considered
>>> Linux specific). For every other device, we don't put this type of
>>> information in DT, but is user controlled.
>> I didn't completely understand your comment.
>> Do you not want these properties to be in DT file?
> 
> Right, not if it is a user decision.
> 
>> When you say user-controlled, do you mean control it through sysfs entries?
> 
> Yes.
> 
>>> So really, wouldn't 1
>>> property be sufficient for cases where a mode doesn't work due to
>>> some h/w limitation. Otherwise, it is an OS or user decision.
>> I didn't completely understand this. Could you please elaborate on your
>> intent here?
> 
> The case that makes sense for this to be in DT is if there are h/w
> limitations that prevent some low power modes. In such a case, that
> limit is not likely specific to runtime PM or system suspend.
> 
>>>>    -lanes-per-direction       : number of lanes available per direction - either 1 or 2.
>>>>                         Note that it is assume same number of lanes is used both
>>>>                         directions at once. If not specified, default is 2 lanes per direction.
>>>> @@ -66,4 +75,6 @@ Example:
>>>>               freq-table-hz = <100000000 200000000>, <0 0>, <0 0>;
>>>>               phys = <&ufsphy1>;
>>>>               phy-names = "ufsphy";
>>>> +            rpm-level = <3>;
>>>
>>> Why specified if 3 is the default?
>> Ah yes - that should be removed.
>> I'll remove it in v2.
>>
>>>
>>>> +            spm-level = <5>;
>>>
>>> These seem like sane defaults. When and why would you use some
>>> different?
>> I think each of the deeper sleep modes are associated with an increasing
>> wakeup latency. For e.g. '0' would have the highest power-consumption
>> and no resume latency at all as compared to '5'.
>> So depending on use-cases other modes may be chosen.
> 
> The use-case can change in a running system. For example if you are
> plugged in, then you probably don't want to enter a lower power mode.
> 
> Rob
> 

Ok - Thanks.
I'm gonna make the following changes in v2:
1. Remove these entries from DT
2. Add support for these entries in sysfs.
3. Keep 3 as the default value for [rpm/spm]-levels

-asd

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a 
Linux Foundation Collaborative Project