scsi: ufs: add option to change default UFS power management level

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).

Change-Id: I45aaae9f46beb3b5d38bcc6dcbd728e79677276c
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
[venkatg@codeaurora.org: resolved trivial merge conflicts]
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>

4 files changed, 44 insertions, 7 deletions

diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
index c9cd219c4a3c..72b2aa03321e 100644
--- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
+++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt
@@ -38,6 +38,14 @@ 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 suppported:
+			  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.
 
 Note: If above properties are not defined it can be assumed that the supply
 regulators or clocks are always on.
@@ -63,6 +71,8 @@ Example:
 		freq-table-hz = <100000000 200000000>, <0 0>, <0 0>;
 		phys = <&ufsphy1>;
 		phy-names = "ufsphy";
+		rpm-level = <3>;
+		spm-level = <5>;
 	};
 
 ==== MSM UFS platform driver properties =====
diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index 967a78470f73..31fe2e5797c8 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -222,6 +222,19 @@ out:
 	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
@@ -326,6 +339,7 @@ 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 7fb477d4f97e..ce37b0e0a1eb 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -266,6 +266,14 @@ ufs_get_desired_pm_lvl_for_dev_link_state(enum ufs_dev_pwr_mode dev_state,
 	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 void ufshcd_tmc_handler(struct ufs_hba *hba);
 static void ufshcd_async_scan(void *data, async_cookie_t cookie);
 static int ufshcd_reset_and_restore(struct ufs_hba *hba);
@@ -6836,14 +6844,19 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	}
 
 	/*
-	 * Set the default power management level for UFS runtime and system
+	 * 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.
 	 */
-	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);
 
 	/* Hold auto suspend until async scan completes */
 	pm_runtime_get_sync(dev);
diff --git a/include/linux/scsi/ufs/ufshcd.h b/include/linux/scsi/ufs/ufshcd.h
index 7b96bbcc70b3..c706837cac76 100644
--- a/include/linux/scsi/ufs/ufshcd.h
+++ b/include/linux/scsi/ufs/ufshcd.h
@@ -473,9 +473,9 @@ 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;