Revert "Revert "Revert "scsi: ufs-qcom: Add flag to keep track of PHY's power state"""

This reverts commit 28652f3b71d2eeb780d61085907c8a04d5ced116.

Change log from v1:
 - add is_binary_power_count to toggle the power_count under phy mutex
 - no funcitonal changes on other components

= v1 description:
This can contribute a race condition between is_phy_pwr_on and phy_power_on/off.
Instead of it, we must rely on mutex with power_count in phy_power_on/off more
precisely. And, in order to fix the origina issue caused by multiple power on/
off, we must use power_count as a flag.

So, the final approach is same as moving "is_phy_pwr_on" under mutex.

Bug: 139262967
Change-Id: Ia2ca0a1187b97e0f5b9e46d8e8465ac0b28d2862
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
Signed-off-by: Alexander Winkowski <dereference23@outlook.com>

drivers/phy/phy-core.c

@@ -299,8 +299,10 @@ int phy_power_on(struct phy *phy)
 			dev_err(&phy->dev, "phy poweron failed --> %d\n", ret);
 			goto err_pwr_on;
 		}
+		++phy->power_count;
+	} else if (!phy->is_binary_power_count) {
+		++phy->power_count;
 	}
-	++phy->power_count;
 	mutex_unlock(&phy->mutex);
 	return 0;
 
@@ -330,8 +332,10 @@ int phy_power_off(struct phy *phy)
 			mutex_unlock(&phy->mutex);
 			return ret;
 		}
+		--phy->power_count;
+	} else if (!phy->is_binary_power_count) {
+		--phy->power_count;
 	}
-	--phy->power_count;
 	mutex_unlock(&phy->mutex);
 	phy_pm_runtime_put(phy);
 

drivers/scsi/ufs/ufs-qcom.c

@@ -830,10 +830,8 @@ static int ufs_qcom_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 	 */
 	if (!ufs_qcom_is_link_active(hba)) {
 		ufs_qcom_disable_lane_clks(host);
-		if (host->is_phy_pwr_on) {
-			phy_power_off(phy);
-			host->is_phy_pwr_on = false;
-		}
+		phy_power_off(phy);
+
 		if (host->vddp_ref_clk && ufs_qcom_is_link_off(hba))
 			ret = ufs_qcom_disable_vreg(hba->dev,
 					host->vddp_ref_clk);
@@ -860,15 +858,13 @@ static int ufs_qcom_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 	struct phy *phy = host->generic_phy;
 	int err;
 
-	if (!host->is_phy_pwr_on) {
-		err = phy_power_on(phy);
-		if (err) {
-			dev_err(hba->dev, "%s: failed enabling regs, err = %d\n",
-				__func__, err);
-			goto out;
-		}
-		host->is_phy_pwr_on = true;
+	err = phy_power_on(phy);
+	if (err) {
+		dev_err(hba->dev, "%s: failed enabling regs, err = %d\n",
+			__func__, err);
+		goto out;
 	}
+
 	if (host->vddp_ref_clk && (hba->rpm_lvl > UFS_PM_LVL_3 ||
 				   hba->spm_lvl > UFS_PM_LVL_3))
 		ufs_qcom_enable_vreg(hba->dev,
@@ -1524,10 +1520,8 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
 		return 0;
 
 	if (on && (status == POST_CHANGE)) {
-		if (!host->is_phy_pwr_on) {
-			phy_power_on(host->generic_phy);
-			host->is_phy_pwr_on = true;
-		}
+		phy_power_on(host->generic_phy);
+
 		/* enable the device ref clock for HS mode*/
 		if (ufshcd_is_hs_mode(&hba->pwr_info))
 			ufs_qcom_dev_ref_clk_ctrl(host, true);
@@ -1544,10 +1538,7 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
 			ufs_qcom_dev_ref_clk_ctrl(host, false);
 
 			/* powering off PHY during aggressive clk gating */
-			if (host->is_phy_pwr_on) {
-				phy_power_off(host->generic_phy);
-				host->is_phy_pwr_on = false;
-			}
+			phy_power_off(host->generic_phy);
 		}
 	}
 
@@ -2148,6 +2139,8 @@ static int ufs_qcom_init(struct ufs_hba *hba)
 			host->dev_ref_clk_en_mask = BIT(5);
 		}
 	}
+	/* use binary power_count to avoid race condition of phy on/off */
+	host->generic_phy->is_binary_power_count = true;
 
 	/* update phy revision information before calling phy_init() */
 	ufs_qcom_phy_save_controller_version(host->generic_phy,
@@ -2156,13 +2149,15 @@ static int ufs_qcom_init(struct ufs_hba *hba)
 	err = ufs_qcom_parse_reg_info(host, "qcom,vddp-ref-clk",
 				      &host->vddp_ref_clk);
 	phy_init(host->generic_phy);
-
+	err = phy_power_on(host->generic_phy);
+	if (err)
+		goto out_unregister_bus;
 	if (host->vddp_ref_clk) {
 		err = ufs_qcom_enable_vreg(dev, host->vddp_ref_clk);
 		if (err) {
 			dev_err(dev, "%s: failed enabling ref clk supply: %d\n",
 				__func__, err);
-			goto out_unregister_bus;
+			goto out_disable_phy;
 		}
 	}
 
@@ -2209,6 +2204,8 @@ out_set_load_vccq_parent:
 out_disable_vddp:
 	if (host->vddp_ref_clk)
 		ufs_qcom_disable_vreg(dev, host->vddp_ref_clk);
+out_disable_phy:
+	phy_power_off(host->generic_phy);
 out_unregister_bus:
 	phy_exit(host->generic_phy);
 	msm_bus_scale_unregister_client(host->bus_vote.client_handle);
@@ -2232,10 +2229,7 @@ static void ufs_qcom_exit(struct ufs_hba *hba)
 
 	msm_bus_scale_unregister_client(host->bus_vote.client_handle);
 	ufs_qcom_disable_lane_clks(host);
-	if (host->is_phy_pwr_on) {
-		phy_power_off(host->generic_phy);
-		host->is_phy_pwr_on = false;
-	}
+	phy_power_off(host->generic_phy);
 	phy_exit(host->generic_phy);
 	ufs_qcom_pm_qos_remove(host);
 }

drivers/scsi/ufs/ufs-qcom.h

@@ -361,7 +361,6 @@ struct ufs_qcom_host {
 	struct ufs_vreg *vddp_ref_clk;
 	struct ufs_vreg *vccq_parent;
 	bool work_pending;
-	bool is_phy_pwr_on;
 
 	/* hw reset info. */
 	unsigned int hw_reset_count;

include/linux/phy/phy.h

@@ -77,6 +77,7 @@ struct phy {
 	struct mutex		mutex;
 	int			init_count;
 	int			power_count;
+	bool			is_binary_power_count;
 	struct phy_attrs	attrs;
 	struct regulator	*pwr;
 };