[PATCH v3 4/5] scsi: ufs-mediatek: Fix unbalanced clock on/off

[Stanley Chu]

MediaTek UFS clocks are separated to two parts and controlled
by different modules: ufs-mediatek and phy-ufs-mediatek.

If both Auto-Hibern8 and clk-gating feature are enabled, mphy
power control is not balanced thus unbalanced control also
happens to the clocks probed by phy-ufs-mediatek module.

Fix this issue by

- Promise usage of phy_power_on/off balanced

- Remove phy_power_on/off control in suspend/resume vops since
  both can be handled in setup_clock vops only

Signed-off-by: Stanley Chu <stanley.chu@xxxxxxxxxxxx>
Reviewed-by: Peter Wang <peter.wang@xxxxxxxxxxxx>
---
 drivers/scsi/ufs/ufs-mediatek.c | 60 ++++++++++++++++++++-------------
 drivers/scsi/ufs/ufs-mediatek.h |  1 +
 2 files changed, 38 insertions(+), 23 deletions(-)

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index 5f41b7b7db8f..1cc7bea1468b 100644
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -205,6 +205,23 @@ int ufs_mtk_wait_link_state(struct ufs_hba *hba, u32 state,
 	return -ETIMEDOUT;
 }
 
+static void ufs_mtk_mphy_power_on(struct ufs_hba *hba, bool on)
+{
+	struct ufs_mtk_host *host = ufshcd_get_variant(hba);
+	struct phy *mphy = host->mphy;
+
+	if (!mphy)
+		return;
+
+	if (on && !host->mphy_powered_on)
+		phy_power_on(mphy);
+	else if (!on && host->mphy_powered_on)
+		phy_power_off(mphy);
+	else
+		return;
+	host->mphy_powered_on = on;
+}
+
 /**
  * ufs_mtk_setup_clocks - enables/disable clocks
  * @hba: host controller instance
@@ -218,6 +235,7 @@ static int ufs_mtk_setup_clocks(struct ufs_hba *hba, bool on,
 {
 	struct ufs_mtk_host *host = ufshcd_get_variant(hba);
 	int ret = 0;
+	bool clk_pwr_off = false;
 
 	/*
 	 * In case ufs_mtk_init() is not yet done, simply ignore.
@@ -228,25 +246,29 @@ static int ufs_mtk_setup_clocks(struct ufs_hba *hba, bool on,
 		return 0;
 
 	if (!on && status == PRE_CHANGE) {
-		if (!ufshcd_is_link_active(hba)) {
-			ufs_mtk_setup_ref_clk(hba, on);
-			ret = phy_power_off(host->mphy);
-		} else {
+		if (ufshcd_is_link_off(hba)) {
+			clk_pwr_off = true;
+		} else if (ufshcd_is_link_hibern8(hba) ||
+			 (!ufshcd_can_hibern8_during_gating(hba) &&
+			 ufshcd_is_auto_hibern8_enabled(hba))) {
 			/*
-			 * Gate ref-clk if link state is in Hibern8
-			 * triggered by Auto-Hibern8.
+			 * Gate ref-clk and poweroff mphy if link state is in
+			 * OFF or Hibern8 by either Auto-Hibern8 or
+			 * ufshcd_link_state_transition().
 			 */
-			if (!ufshcd_can_hibern8_during_gating(hba) &&
-			    ufshcd_is_auto_hibern8_enabled(hba)) {
-				ret = ufs_mtk_wait_link_state(hba,
-							      VS_LINK_HIBERN8,
-							      15);
-				if (!ret)
-					ufs_mtk_setup_ref_clk(hba, on);
-			}
+			ret = ufs_mtk_wait_link_state(hba,
+						      VS_LINK_HIBERN8,
+						      15);
+			if (!ret)
+				clk_pwr_off = true;
+		}
+
+		if (clk_pwr_off) {
+			ufs_mtk_setup_ref_clk(hba, on);
+			ufs_mtk_mphy_power_on(hba, on);
 		}
 	} else if (on && status == POST_CHANGE) {
-		ret = phy_power_on(host->mphy);
+		ufs_mtk_mphy_power_on(hba, on);
 		ufs_mtk_setup_ref_clk(hba, on);
 	}
 
@@ -538,7 +560,6 @@ static void ufs_mtk_vreg_set_lpm(struct ufs_hba *hba, bool lpm)
 static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 {
 	int err;
-	struct ufs_mtk_host *host = ufshcd_get_variant(hba);
 
 	if (ufshcd_is_link_hibern8(hba)) {
 		err = ufs_mtk_link_set_lpm(hba);
@@ -559,20 +580,13 @@ static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 		ufs_mtk_vreg_set_lpm(hba, true);
 	}
 
-	if (!ufshcd_is_link_active(hba))
-		phy_power_off(host->mphy);
-
 	return 0;
 }
 
 static int ufs_mtk_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 {
-	struct ufs_mtk_host *host = ufshcd_get_variant(hba);
 	int err;
 
-	if (!ufshcd_is_link_active(hba))
-		phy_power_on(host->mphy);
-
 	if (ufshcd_is_link_hibern8(hba)) {
 		ufs_mtk_vreg_set_lpm(hba, false);
 		err = ufs_mtk_link_set_hpm(hba);
diff --git a/drivers/scsi/ufs/ufs-mediatek.h b/drivers/scsi/ufs/ufs-mediatek.h
index fc42dcbfd800..6052ec105aba 100644
--- a/drivers/scsi/ufs/ufs-mediatek.h
+++ b/drivers/scsi/ufs/ufs-mediatek.h
@@ -91,6 +91,7 @@ enum {
 struct ufs_mtk_host {
 	struct ufs_hba *hba;
 	struct phy *mphy;
+	bool mphy_powered_on;
 	bool unipro_lpm;
 	bool ref_clk_enabled;
 	u16 ref_clk_ungating_wait_us;
-- 
2.18.0