scsi: ufs: Clean up and refactor clk-scaling feature

Manipulate clock scaling related stuff only if the host capability supports
clock scaling feature to avoid redundant code execution.

Link: https://lore.kernel.org/r/20210120150142.5049-4-stanley.chu@mediatek.comReviewed-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufshcd.c

@@ -1500,9 +1500,6 @@ static void ufshcd_suspend_clkscaling(struct ufs_hba *hba)
 	unsigned long flags;
 	bool suspend = false;
 
-	if (!ufshcd_is_clkscaling_supported(hba))
-		return;
-
 	cancel_work_sync(&hba->clk_scaling.suspend_work);
 	cancel_work_sync(&hba->clk_scaling.resume_work);
 
@@ -1522,9 +1519,6 @@ static void ufshcd_resume_clkscaling(struct ufs_hba *hba)
 	unsigned long flags;
 	bool resume = false;
 
-	if (!ufshcd_is_clkscaling_supported(hba))
-		return;
-
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	if (hba->clk_scaling.is_suspended) {
 		resume = true;
@@ -5758,6 +5752,26 @@ static inline void ufshcd_schedule_eh_work(struct ufs_hba *hba)
 	}
 }
 
+static void ufshcd_clk_scaling_allow(struct ufs_hba *hba, bool allow)
+{
+	down_write(&hba->clk_scaling_lock);
+	hba->clk_scaling.is_allowed = allow;
+	up_write(&hba->clk_scaling_lock);
+}
+
+static void ufshcd_clk_scaling_suspend(struct ufs_hba *hba, bool suspend)
+{
+	if (suspend) {
+		if (hba->clk_scaling.is_enabled)
+			ufshcd_suspend_clkscaling(hba);
+		ufshcd_clk_scaling_allow(hba, false);
+	} else {
+		ufshcd_clk_scaling_allow(hba, true);
+		if (hba->clk_scaling.is_enabled)
+			ufshcd_resume_clkscaling(hba);
+	}
+}
+
 static void ufshcd_err_handling_prepare(struct ufs_hba *hba)
 {
 	pm_runtime_get_sync(hba->dev);
@@ -5782,22 +5796,18 @@ static void ufshcd_err_handling_prepare(struct ufs_hba *hba)
 		ufshcd_vops_resume(hba, pm_op);
 	} else {
 		ufshcd_hold(hba, false);
-		if (hba->clk_scaling.is_enabled)
+		if (ufshcd_is_clkscaling_supported(hba) &&
+		    hba->clk_scaling.is_enabled)
 			ufshcd_suspend_clkscaling(hba);
-		down_write(&hba->clk_scaling_lock);
-		hba->clk_scaling.is_allowed = false;
-		up_write(&hba->clk_scaling_lock);
+		ufshcd_clk_scaling_allow(hba, false);
 	}
 }
 
 static void ufshcd_err_handling_unprepare(struct ufs_hba *hba)
 {
 	ufshcd_release(hba);
-	down_write(&hba->clk_scaling_lock);
-	hba->clk_scaling.is_allowed = true;
-	up_write(&hba->clk_scaling_lock);
-	if (hba->clk_scaling.is_enabled)
-		ufshcd_resume_clkscaling(hba);
+	if (ufshcd_is_clkscaling_supported(hba))
+		ufshcd_clk_scaling_suspend(hba, false);
 	pm_runtime_put(hba->dev);
 }
 
@@ -8694,12 +8704,8 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 	ufshcd_hold(hba, false);
 	hba->clk_gating.is_suspended = true;
 
-	if (hba->clk_scaling.is_enabled)
-		ufshcd_suspend_clkscaling(hba);
-
-	down_write(&hba->clk_scaling_lock);
-	hba->clk_scaling.is_allowed = false;
-	up_write(&hba->clk_scaling_lock);
+	if (ufshcd_is_clkscaling_supported(hba))
+		ufshcd_clk_scaling_suspend(hba, true);
 
 	if (req_dev_pwr_mode == UFS_ACTIVE_PWR_MODE &&
 			req_link_state == UIC_LINK_ACTIVE_STATE) {
@@ -8819,11 +8825,9 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 	if (!ufshcd_set_dev_pwr_mode(hba, UFS_ACTIVE_PWR_MODE))
 		ufshcd_disable_auto_bkops(hba);
 enable_gating:
-	down_write(&hba->clk_scaling_lock);
-	hba->clk_scaling.is_allowed = true;
-	up_write(&hba->clk_scaling_lock);
-	if (hba->clk_scaling.is_enabled)
-		ufshcd_resume_clkscaling(hba);
+	if (ufshcd_is_clkscaling_supported(hba))
+		ufshcd_clk_scaling_suspend(hba, false);
+
 	hba->clk_gating.is_suspended = false;
 	hba->dev_info.b_rpm_dev_flush_capable = false;
 	ufshcd_release(hba);
@@ -8925,11 +8929,8 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 
 	hba->clk_gating.is_suspended = false;
 
-	down_write(&hba->clk_scaling_lock);
-	hba->clk_scaling.is_allowed = true;
-	up_write(&hba->clk_scaling_lock);
-	if (hba->clk_scaling.is_enabled)
-		ufshcd_resume_clkscaling(hba);
+	if (ufshcd_is_clkscaling_supported(hba))
+		ufshcd_clk_scaling_suspend(hba, false);
 
 	/* Enable Auto-Hibernate if configured */
 	ufshcd_auto_hibern8_enable(hba);