2 files changed, 54 insertions, 32 deletions

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 1654f0ede0cd..8224250268c3 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1198,19 +1198,30 @@ static int ufshcd_clock_scaling_prepare(struct ufs_hba *hba)
 	 */
 	ufshcd_scsi_block_requests(hba);
 	down_write(&hba->clk_scaling_lock);
-	if (ufshcd_wait_for_doorbell_clr(hba, DOORBELL_CLR_TOUT_US)) {
+
+	if (!hba->clk_scaling.is_allowed ||
+	    ufshcd_wait_for_doorbell_clr(hba, DOORBELL_CLR_TOUT_US)) {
 		ret = -EBUSY;
 		up_write(&hba->clk_scaling_lock);
 		ufshcd_scsi_unblock_requests(hba);
+		goto out;
 	}
 
+	/* let's not get into low power until clock scaling is completed */
+	ufshcd_hold(hba, false);
+
+out:
 	return ret;
 }
 
-static void ufshcd_clock_scaling_unprepare(struct ufs_hba *hba)
+static void ufshcd_clock_scaling_unprepare(struct ufs_hba *hba, bool writelock)
 {
-	up_write(&hba->clk_scaling_lock);
+	if (writelock)
+		up_write(&hba->clk_scaling_lock);
+	else
+		up_read(&hba->clk_scaling_lock);
 	ufshcd_scsi_unblock_requests(hba);
+	ufshcd_release(hba);
 }
 
 /**
@@ -1225,13 +1236,11 @@ static void ufshcd_clock_scaling_unprepare(struct ufs_hba *hba)
 static int ufshcd_devfreq_scale(struct ufs_hba *hba, bool scale_up)
 {
 	int ret = 0;
-
-	/* let's not get into low power until clock scaling is completed */
-	ufshcd_hold(hba, false);
+	bool is_writelock = true;
 
 	ret = ufshcd_clock_scaling_prepare(hba);
 	if (ret)
-		goto out;
+		return ret;
 
 	/* scale down the gear before scaling down clocks */
 	if (!scale_up) {
@@ -1257,14 +1266,12 @@ static int ufshcd_devfreq_scale(struct ufs_hba *hba, bool scale_up)
 	}
 
 	/* Enable Write Booster if we have scaled up else disable it */
-	up_write(&hba->clk_scaling_lock);
+	downgrade_write(&hba->clk_scaling_lock);
+	is_writelock = false;
 	ufshcd_wb_ctrl(hba, scale_up);
-	down_write(&hba->clk_scaling_lock);
 
 out_unprepare:
-	ufshcd_clock_scaling_unprepare(hba);
-out:
-	ufshcd_release(hba);
+	ufshcd_clock_scaling_unprepare(hba, is_writelock);
 	return ret;
 }
 
@@ -1538,7 +1545,7 @@ static ssize_t ufshcd_clkscale_enable_show(struct device *dev,
 {
 	struct ufs_hba *hba = dev_get_drvdata(dev);
 
-	return snprintf(buf, PAGE_SIZE, "%d\n", hba->clk_scaling.is_allowed);
+	return snprintf(buf, PAGE_SIZE, "%d\n", hba->clk_scaling.is_enabled);
 }
 
 static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
@@ -1558,7 +1565,7 @@ static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
 	}
 
 	value = !!value;
-	if (value == hba->clk_scaling.is_allowed)
+	if (value == hba->clk_scaling.is_enabled)
 		goto out;
 
 	pm_runtime_get_sync(hba->dev);
@@ -1567,7 +1574,7 @@ static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
 	cancel_work_sync(&hba->clk_scaling.suspend_work);
 	cancel_work_sync(&hba->clk_scaling.resume_work);
 
-	hba->clk_scaling.is_allowed = value;
+	hba->clk_scaling.is_enabled = value;
 
 	if (value) {
 		ufshcd_resume_clkscaling(hba);
@@ -1906,8 +1913,6 @@ static void ufshcd_init_clk_scaling(struct ufs_hba *hba)
 	snprintf(wq_name, sizeof(wq_name), "ufs_clkscaling_%d",
 		 hba->host->host_no);
 	hba->clk_scaling.workq = create_singlethread_workqueue(wq_name);
-
-	ufshcd_clkscaling_init_sysfs(hba);
 }
 
 static void ufshcd_exit_clk_scaling(struct ufs_hba *hba)
@@ -1915,6 +1920,8 @@ static void ufshcd_exit_clk_scaling(struct ufs_hba *hba)
 	if (!ufshcd_is_clkscaling_supported(hba))
 		return;
 
+	if (hba->clk_scaling.enable_attr.attr.name)
+		device_remove_file(hba->dev, &hba->clk_scaling.enable_attr);
 	destroy_workqueue(hba->clk_scaling.workq);
 	ufshcd_devfreq_remove(hba);
 }
@@ -1979,7 +1986,7 @@ static void ufshcd_clk_scaling_start_busy(struct ufs_hba *hba)
 	if (!hba->clk_scaling.active_reqs++)
 		queue_resume_work = true;
 
-	if (!hba->clk_scaling.is_allowed || hba->pm_op_in_progress)
+	if (!hba->clk_scaling.is_enabled || hba->pm_op_in_progress)
 		return;
 
 	if (queue_resume_work)
@@ -5763,18 +5770,24 @@ 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_allowed) {
+		if (hba->clk_scaling.is_enabled) {
 			cancel_work_sync(&hba->clk_scaling.suspend_work);
 			cancel_work_sync(&hba->clk_scaling.resume_work);
 			ufshcd_suspend_clkscaling(hba);
 		}
+		down_write(&hba->clk_scaling_lock);
+		hba->clk_scaling.is_allowed = false;
+		up_write(&hba->clk_scaling_lock);
 	}
 }
 
 static void ufshcd_err_handling_unprepare(struct ufs_hba *hba)
 {
 	ufshcd_release(hba);
-	if (hba->clk_scaling.is_allowed)
+	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);
 	pm_runtime_put(hba->dev);
 }
@@ -7747,12 +7760,14 @@ static int ufshcd_add_lus(struct ufs_hba *hba)
 			sizeof(struct ufs_pa_layer_attr));
 		hba->clk_scaling.saved_pwr_info.is_valid = true;
 		if (!hba->devfreq) {
+			hba->clk_scaling.is_allowed = true;
 			ret = ufshcd_devfreq_init(hba);
 			if (ret)
 				goto out;
-		}
 
-		hba->clk_scaling.is_allowed = true;
+			hba->clk_scaling.is_enabled = true;
+			ufshcd_clkscaling_init_sysfs(hba);
+		}
 	}
 
 	ufs_bsg_probe(hba);
@@ -8672,11 +8687,14 @@ 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_allowed) {
+	if (hba->clk_scaling.is_enabled) {
 		cancel_work_sync(&hba->clk_scaling.suspend_work);
 		cancel_work_sync(&hba->clk_scaling.resume_work);
 		ufshcd_suspend_clkscaling(hba);
 	}
+	down_write(&hba->clk_scaling_lock);
+	hba->clk_scaling.is_allowed = false;
+	up_write(&hba->clk_scaling_lock);
 
 	if (req_dev_pwr_mode == UFS_ACTIVE_PWR_MODE &&
 			req_link_state == UIC_LINK_ACTIVE_STATE) {
@@ -8773,8 +8791,6 @@ disable_clks:
 	goto out;
 
 set_link_active:
-	if (hba->clk_scaling.is_allowed)
-		ufshcd_resume_clkscaling(hba);
 	ufshcd_vreg_set_hpm(hba);
 	/*
 	 * Device hardware reset is required to exit DeepSleep. Also, for
@@ -8798,7 +8814,10 @@ set_dev_active:
 	if (!ufshcd_set_dev_pwr_mode(hba, UFS_ACTIVE_PWR_MODE))
 		ufshcd_disable_auto_bkops(hba);
 enable_gating:
-	if (hba->clk_scaling.is_allowed)
+	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);
 	hba->clk_gating.is_suspended = false;
 	hba->dev_info.b_rpm_dev_flush_capable = false;
@@ -8901,7 +8920,10 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 
 	hba->clk_gating.is_suspended = false;
 
-	if (hba->clk_scaling.is_allowed)
+	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);
 
 	/* Enable Auto-Hibernate if configured */
@@ -8923,8 +8945,6 @@ vendor_suspend:
 	ufshcd_vops_suspend(hba, pm_op);
 disable_irq_and_vops_clks:
 	ufshcd_disable_irq(hba);
-	if (hba->clk_scaling.is_allowed)
-		ufshcd_suspend_clkscaling(hba);
 	ufshcd_setup_clocks(hba, false);
 	if (ufshcd_is_clkgating_allowed(hba)) {
 		hba->clk_gating.state = CLKS_OFF;
@@ -9165,8 +9185,6 @@ void ufshcd_remove(struct ufs_hba *hba)
 
 	ufshcd_exit_clk_scaling(hba);
 	ufshcd_exit_clk_gating(hba);
-	if (ufshcd_is_clkscaling_supported(hba))
-		device_remove_file(hba->dev, &hba->clk_scaling.enable_attr);
 	ufshcd_hba_exit(hba);
 }
 EXPORT_SYMBOL_GPL(ufshcd_remove);
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 003bd1172b06..cfe76b1e0e9c 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -419,7 +419,10 @@ struct ufs_saved_pwr_info {
  * @suspend_work: worker to suspend devfreq
  * @resume_work: worker to resume devfreq
  * @min_gear: lowest HS gear to scale down to
- * @is_allowed: tracks if scaling is currently allowed or not
+ * @is_enabled: tracks if scaling is currently enabled or not, controlled by
+		clkscale_enable sysfs node
+ * @is_allowed: tracks if scaling is currently allowed or not, used to block
+		clock scaling which is not invoked from devfreq governor
  * @is_busy_started: tracks if busy period has started or not
  * @is_suspended: tracks if devfreq is suspended or not
  */
@@ -434,6 +437,7 @@ struct ufs_clk_scaling {
 	struct work_struct suspend_work;
 	struct work_struct resume_work;
 	u32 min_gear;
+	bool is_enabled;
 	bool is_allowed;
 	bool is_busy_started;
 	bool is_suspended;