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[V5,10/11] scsi: ufs: qcom : Introduce phy_power_on/off wrapper function

Message ID 20250515162722.6933-11-quic_nitirawa@quicinc.com
State New
Headers show
Series [V5,01/11] scsi: ufs: qcom: add a new phy calibrate API call | expand

Commit Message

Nitin Rawat May 15, 2025, 4:27 p.m. UTC 
There can be scenarios where phy_power_on is called when PHY is
already on (phy_count=1). For instance, ufs_qcom_power_up_sequence
can be called multiple times from ufshcd_link_startup as part of
ufshcd_hba_enable call for each link startup retries(max retries =3),
causing the PHY reference count to increase and leading to inconsistent
phy behavior.

Similarly, there can be scenarios where phy_power_on or phy_power_off
might be called directly from the UFS controller driver when the PHY
is already powered on or off respectiely, causing similar issues.

To fix this, introduce ufs_qcom_phy_power_on and ufs_qcom_phy_power_off
wrappers for phy_power_on and phy_power_off. These wrappers will use an
is_phy_pwr_on flag to check if the PHY is already powered on or off,
avoiding redundant calls. Protect the is_phy_pwr_on flag with a mutex
to ensure safe usage and prevent race conditions.

Co-developed-by: Can Guo <quic_cang@quicinc.com>
Signed-off-by: Can Guo <quic_cang@quicinc.com>
Signed-off-by: Nitin Rawat <quic_nitirawa@quicinc.com>
---
 drivers/ufs/host/ufs-qcom.c | 44 +++++++++++++++++++++++++++++++------
 drivers/ufs/host/ufs-qcom.h |  4 ++++
 2 files changed, 41 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
index 3ee4ab90dfba..583db910efd4 100644
--- a/drivers/ufs/host/ufs-qcom.c
+++ b/drivers/ufs/host/ufs-qcom.c
@@ -479,6 +479,38 @@  static u32 ufs_qcom_get_hs_gear(struct ufs_hba *hba)
 	return UFS_HS_G3;
 }
 
+static int ufs_qcom_phy_power_on(struct ufs_hba *hba)
+{
+	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
+	struct phy *phy = host->generic_phy;
+	int ret = 0;
+
+	guard(mutex)(&host->phy_mutex);
+	if (!host->is_phy_pwr_on) {
+		ret = phy_power_on(phy);
+		if (!ret)
+			host->is_phy_pwr_on = true;
+	}
+
+	return ret;
+}
+
+static int ufs_qcom_phy_power_off(struct ufs_hba *hba)
+{
+	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
+	struct phy *phy = host->generic_phy;
+	int ret = 0;
+
+	guard(mutex)(&host->phy_mutex);
+	if (host->is_phy_pwr_on) {
+		ret = phy_power_off(phy);
+		if (!ret)
+			host->is_phy_pwr_on = false;
+	}
+
+	return ret;
+}
+
 static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
 {
 	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
@@ -507,7 +539,7 @@  static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
 		return ret;
 
 	if (phy->power_count) {
-		phy_power_off(phy);
+		ufs_qcom_phy_power_off(hba);
 		phy_exit(phy);
 	}
 
@@ -524,7 +556,7 @@  static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
 		goto out_disable_phy;
 
 	/* power on phy - start serdes and phy's power and clocks */
-	ret = phy_power_on(phy);
+	ret = ufs_qcom_phy_power_on(hba);
 	if (ret) {
 		dev_err(hba->dev, "%s: phy power on failed, ret = %d\n",
 			__func__, ret);
@@ -1121,7 +1153,6 @@  static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
 				 enum ufs_notify_change_status status)
 {
 	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
-	struct phy *phy = host->generic_phy;
 	int err;
 
 	/*
@@ -1142,7 +1173,7 @@  static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
 				ufs_qcom_dev_ref_clk_ctrl(host, false);
 			}
 
-			err = phy_power_off(phy);
+			err = ufs_qcom_phy_power_off(hba);
 			if (err) {
 				dev_err(hba->dev, "phy power off failed, ret=%d\n", err);
 				return err;
@@ -1151,7 +1182,7 @@  static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
 		break;
 	case POST_CHANGE:
 		if (on) {
-			err = phy_power_on(phy);
+			err = ufs_qcom_phy_power_on(hba);
 			if (err) {
 				dev_err(hba->dev, "phy power on failed, ret = %d\n", err);
 				return err;
@@ -1339,10 +1370,9 @@  static int ufs_qcom_init(struct ufs_hba *hba)
 static void ufs_qcom_exit(struct ufs_hba *hba)
 {
 	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
-	struct phy *phy = host->generic_phy;
 
 	ufs_qcom_disable_lane_clks(host);
-	phy_power_off(phy);
+	ufs_qcom_phy_power_off(hba);
 	phy_exit(host->generic_phy);
 }
 
diff --git a/drivers/ufs/host/ufs-qcom.h b/drivers/ufs/host/ufs-qcom.h
index 0a5cfc2dd4f7..f51b774e17be 100644
--- a/drivers/ufs/host/ufs-qcom.h
+++ b/drivers/ufs/host/ufs-qcom.h
@@ -281,6 +281,10 @@  struct ufs_qcom_host {
 	u32 phy_gear;
 
 	bool esi_enabled;
+	/* flag to check if phy is powered on */
+	bool is_phy_pwr_on;
+	/* Protect the usage of is_phy_pwr_on against racing */
+	struct mutex phy_mutex;
 };
 
 struct ufs_qcom_drvdata {