linux-kernel - [PATCH v2 4/5] scsi: ufs-mediatek: Fix unbalanced clock on/off

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Date:   Fri, 29 May 2020 17:23:09 +0800
From:   Stanley Chu <stanley.chu@...iatek.com>
To:     <linux-scsi@...r.kernel.org>, <martin.petersen@...cle.com>,
        <avri.altman@....com>, <alim.akhtar@...sung.com>,
        <jejb@...ux.ibm.com>
CC:     <beanhuo@...ron.com>, <asutoshd@...eaurora.org>,
        <cang@...eaurora.org>, <matthias.bgg@...il.com>,
        <bvanassche@....org>, <linux-mediatek@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <kuohong.wang@...iatek.com>,
        <peter.wang@...iatek.com>, <chun-hung.wu@...iatek.com>,
        <andy.teng@...iatek.com>, <cc.chou@...iatek.com>,
        <chaotian.jing@...iatek.com>, <pengshun.zhao@...iatek.com>,
        Stanley Chu <stanley.chu@...iatek.com>
Subject: [PATCH v2 4/5] scsi: ufs-mediatek: Fix unbalanced clock on/off

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@...iatek.com>
Reviewed-by: Peter Wang <peter.wang@...iatek.com>
---
 drivers/scsi/ufs/ufs-mediatek.c | 56 +++++++++++++++++++--------------
 1 file changed, 32 insertions(+), 24 deletions(-)

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index 5f41b7b7db8f..de9e643fb8dd 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
@@ -228,25 +245,24 @@ 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 {
-			/*
-			 * Gate ref-clk if link state is in Hibern8
-			 * triggered by Auto-Hibern8.
-			 */
-			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);
+		/*
+		 * Gate ref-clk and poweroff mphy if link state is in OFF
+		 * or Hibern8 by either ufshcd_link_state_transition() or
+		 * Auto-Hibern8.
+		 */
+		if (!ufshcd_is_link_active(hba) ||
+			(!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);
+				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 +554,6 @@ 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 +574,13 @@ 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);
-- 
2.18.0