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Three changes related with UFS clock scaling

PATCH Applied Can Guo 3 participants 7 messages Jan 20, 2021 – Jan 23, 2021

Subsystems (2)
SCSI Arm MediaTek
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Can Guo

author
#0 lore raw

v11 cover Three changes related with UFS clock scaling

This series is made based on 5.12/scsi-queue branch.

Current devfreq framework allows sysfs nodes like governor, min_freq and max_freq to be changed even after devfreq device is suspended. Meanwhile, devfreq_suspend_device() cannot/wouldn't synchronize clock scaling which has already been invoked through devfreq sysfs nodes menitioned above. It means that clock scaling invoked through these devfreq sysfs nodes can happen at any time regardless of the state of UFS host and/or device. We need to control and synchronize clock scaling in this scenario.

The 1st change allows contexts to prevent clock scaling from being invoked through devfreq sysfs nodes.
The 2nd change is just a code cleanup for clk_scaling/gating initialization routine.
The 3rd change reverts one old change which can be covered by the 1st change. For branches which do not have this change yet, it can be ignored.

Change since v10:
- Incorporated Stanley's comment.

Change since v9:
- Minor update in the 1st change.

Change since v8:
- Rebased on 5.12/scsi-queue

Change since v7:
- Slightly updated the 1st change: changed the up_write() before ufshcd_wb_ctrl() to downgrade_write() in ufshcd_devfreq_scale(), so that ufshcd_wb_ctrl() is called with clk_scale_lock held, this is to make sure race condition won't happen to ufshcd_wb_ctrl().

Change since v6:
- Updated the 2nd change

Change since v5:
- Reomved the code change in ufshcd_shutdown() since it is not quite relevant with this fix

Change since v4:
- Updated some comment lines as requested by Stanley

Change since v3:
- Slightly updated the 1st change

Change since v2:
- Split the 1st change to two changes, which become the 1st change and the 3rd change

Change since v1:
- Updated the 2nd change

Can Guo (3):
scsi: ufs: Protect some contexts from unexpected clock scaling
scsi: ufs: Refactor ufshcd_init/exit_clk_scaling/gating()
scsi: ufs: Revert "Make sure clk scaling happens only when HBA is
runtime ACTIVE"

 drivers/scsi/ufs/ufshcd.c | 211 +++++++++++++++++++++++++---------------------
 drivers/scsi/ufs/ufshcd.h |  10 ++-
 2 files changed, 125 insertions(+), 96 deletions(-)
Signature · 1 line
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
author
#1 lore raw

PATCH v11 1/3 scsi: ufs: Protect some contexts from unexpected clock scaling

In contexts like suspend, shutdown and error handling, we need to suspend devfreq to make sure these contexts won't be disturbed by clock scaling. However, suspending devfreq is not enough since users can still trigger a clock scaling by manipulating the devfreq sysfs nodes like min/max_freq and governor even after devfreq is suspended. Moreover, mere suspending devfreq cannot synchroinze a clock scaling which has already been invoked through these sysfs nodes. Add one more flag in struct clk_scaling and wrap the entire func ufshcd_devfreq_scale() with the clk_scaling_lock, so that we can use this flag and clk_scaling_lock to control and synchronize clock scaling invoked through devfreq sysfs nodes.

Signed-off-by Can Guo <[email protected]>
---
 drivers/scsi/ufs/ufshcd.c | 80 +++++++++++++++++++++++++++++------------------
 drivers/scsi/ufs/ufshcd.h |  6 +++-
 2 files changed, 54 insertions(+), 32 deletions(-)
drivers/scsi/ufs/ufshcd.c +49 -31
index 82ad317..8dc4a3a 100644
@@ -1181,19 +1181,30 @@ 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);
 }
 
 /**

@@ -1208,13 +1219,11 @@ 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) {

@@ -1240,14 +1249,12 @@ 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;
 }
 

@@ -1521,7 +1528,7 @@ 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,

@@ -1535,7 +1542,7 @@ static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
 		return -EINVAL;
 
 	value = !!value;
-	if (value == hba->clk_scaling.is_allowed)
+	if (value == hba->clk_scaling.is_enabled)
 		goto out;
 
 	pm_runtime_get_sync(hba->dev);

@@ -1544,7 +1551,7 @@ 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);

@@ -1882,8 +1889,6 @@ 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)

@@ -1891,6 +1896,8 @@ 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);
 }

@@ -1955,7 +1962,7 @@ 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)

@@ -5737,18 +5744,24 @@ 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);
 }

@@ -7728,12 +7741,14 @@ 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);

@@ -8650,11 +8665,14 @@ 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) {

@@ -8751,8 +8769,6 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 	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

@@ -8776,7 +8792,10 @@ 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:
-	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;

@@ -8879,7 +8898,10 @@ 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 */

@@ -8903,8 +8925,6 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 	ufshcd_vreg_set_lpm(hba);
 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;

@@ -9131,8 +9151,6 @@ 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);
drivers/scsi/ufs/ufshcd.h +5 -1
index aa9ea35..2863af1 100644
@@ -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;
Signature · 1 line
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
Reviewed-by on v11 1/3
#2 lore raw

Re: [PATCH v11 1/3] scsi: ufs: Protect some contexts from unexpected clock scaling

Quoted 11 lines · Can Guo

In contexts like suspend, shutdown and error handling, we need to suspend devfreq to make sure these contexts won't be disturbed by clock scaling. However, suspending devfreq is not enough since users can still trigger a clock scaling by manipulating the devfreq sysfs nodes like min/max_freq and governor even after devfreq is suspended. Moreover, mere suspending devfreq cannot synchroinze a clock scaling which has already been invoked through these sysfs nodes. Add one more flag in struct clk_scaling and wrap the entire func ufshcd_devfreq_scale() with the clk_scaling_lock, so that we can use this flag and clk_scaling_lock to control and synchronize clock scaling invoked through devfreq sysfs nodes.

Quoted 1 line
Signed-off-by Can Guo <[email protected]>
Reviewed-by Stanley Chu <[email protected]>
author
#3 lore raw

PATCH v11 2/3 scsi: ufs: Refactor ufshcd_init/exit_clk_scaling/gating()

In reply to Can Guo

ufshcd_hba_exit() is always called after ufshcd_exit_clk_scaling() and ufshcd_exit_clk_gating(), so move ufshcd_exit_clk_scaling/gating() to ufshcd_hba_exit(). Meanwhile, add dedicated funcs to init and remove sysfs nodes of clock scaling/gating to make the code more readable. Overall functionality remains same.

Reviewed-by Stanley Chu <[email protected]>
Signed-off-by Can Guo <[email protected]>
---
 drivers/scsi/ufs/ufshcd.c | 130 +++++++++++++++++++++++++---------------------
 drivers/scsi/ufs/ufshcd.h |   4 ++
 2 files changed, 74 insertions(+), 60 deletions(-)
drivers/scsi/ufs/ufshcd.c +70 -60
index 8dc4a3a..750cf0d 100644
@@ -1569,7 +1569,7 @@ static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
 	return count;
 }
 
-static void ufshcd_clkscaling_init_sysfs(struct ufs_hba *hba)
+static void ufshcd_init_clk_scaling_sysfs(struct ufs_hba *hba)
 {
 	hba->clk_scaling.enable_attr.show = ufshcd_clkscale_enable_show;
 	hba->clk_scaling.enable_attr.store = ufshcd_clkscale_enable_store;

@@ -1580,6 +1580,42 @@ static void ufshcd_clkscaling_init_sysfs(struct ufs_hba *hba)
 		dev_err(hba->dev, "Failed to create sysfs for clkscale_enable\n");
 }
 
+static void ufshcd_remove_clk_scaling_sysfs(struct ufs_hba *hba)
+{
+	if (hba->clk_scaling.enable_attr.attr.name)
+		device_remove_file(hba->dev, &hba->clk_scaling.enable_attr);
+}
+
+static void ufshcd_init_clk_scaling(struct ufs_hba *hba)
+{
+	char wq_name[sizeof("ufs_clkscaling_00")];
+
+	if (!ufshcd_is_clkscaling_supported(hba))
+		return;
+
+	INIT_WORK(&hba->clk_scaling.suspend_work,
+		  ufshcd_clk_scaling_suspend_work);
+	INIT_WORK(&hba->clk_scaling.resume_work,
+		  ufshcd_clk_scaling_resume_work);
+
+	snprintf(wq_name, sizeof(wq_name), "ufs_clkscaling_%d",
+		 hba->host->host_no);
+	hba->clk_scaling.workq = create_singlethread_workqueue(wq_name);
+
+	hba->clk_scaling.is_initialized = true;
+}
+
+static void ufshcd_exit_clk_scaling(struct ufs_hba *hba)
+{
+	if (!hba->clk_scaling.is_initialized)
+		return;
+
+	ufshcd_remove_clk_scaling_sysfs(hba);
+	destroy_workqueue(hba->clk_scaling.workq);
+	ufshcd_devfreq_remove(hba);
+	hba->clk_scaling.is_initialized = false;
+}
+
 static void ufshcd_ungate_work(struct work_struct *work)
 {
 	int ret;

@@ -1871,35 +1907,31 @@ static ssize_t ufshcd_clkgate_enable_store(struct device *dev,
 	return count;
 }
 
-static void ufshcd_init_clk_scaling(struct ufs_hba *hba)
+static void ufshcd_init_clk_gating_sysfs(struct ufs_hba *hba)
 {
-	char wq_name[sizeof("ufs_clkscaling_00")];
-
-	if (!ufshcd_is_clkscaling_supported(hba))
-		return;
-
-	if (!hba->clk_scaling.min_gear)
-		hba->clk_scaling.min_gear = UFS_HS_G1;
-
-	INIT_WORK(&hba->clk_scaling.suspend_work,
-		  ufshcd_clk_scaling_suspend_work);
-	INIT_WORK(&hba->clk_scaling.resume_work,
-		  ufshcd_clk_scaling_resume_work);
+	hba->clk_gating.delay_attr.show = ufshcd_clkgate_delay_show;
+	hba->clk_gating.delay_attr.store = ufshcd_clkgate_delay_store;
+	sysfs_attr_init(&hba->clk_gating.delay_attr.attr);
+	hba->clk_gating.delay_attr.attr.name = "clkgate_delay_ms";
+	hba->clk_gating.delay_attr.attr.mode = 0644;
+	if (device_create_file(hba->dev, &hba->clk_gating.delay_attr))
+		dev_err(hba->dev, "Failed to create sysfs for clkgate_delay\n");
 
-	snprintf(wq_name, sizeof(wq_name), "ufs_clkscaling_%d",
-		 hba->host->host_no);
-	hba->clk_scaling.workq = create_singlethread_workqueue(wq_name);
+	hba->clk_gating.enable_attr.show = ufshcd_clkgate_enable_show;
+	hba->clk_gating.enable_attr.store = ufshcd_clkgate_enable_store;
+	sysfs_attr_init(&hba->clk_gating.enable_attr.attr);
+	hba->clk_gating.enable_attr.attr.name = "clkgate_enable";
+	hba->clk_gating.enable_attr.attr.mode = 0644;
+	if (device_create_file(hba->dev, &hba->clk_gating.enable_attr))
+		dev_err(hba->dev, "Failed to create sysfs for clkgate_enable\n");
 }
 
-static void ufshcd_exit_clk_scaling(struct ufs_hba *hba)
+static void ufshcd_remove_clk_gating_sysfs(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);
+	if (hba->clk_gating.delay_attr.attr.name)
+		device_remove_file(hba->dev, &hba->clk_gating.delay_attr);
+	if (hba->clk_gating.enable_attr.attr.name)
+		device_remove_file(hba->dev, &hba->clk_gating.enable_attr);
 }
 
 static void ufshcd_init_clk_gating(struct ufs_hba *hba)

@@ -1920,34 +1952,21 @@ static void ufshcd_init_clk_gating(struct ufs_hba *hba)
 	hba->clk_gating.clk_gating_workq = alloc_ordered_workqueue(wq_name,
 					WQ_MEM_RECLAIM | WQ_HIGHPRI);
 
-	hba->clk_gating.is_enabled = true;
+	ufshcd_init_clk_gating_sysfs(hba);
 
-	hba->clk_gating.delay_attr.show = ufshcd_clkgate_delay_show;
-	hba->clk_gating.delay_attr.store = ufshcd_clkgate_delay_store;
-	sysfs_attr_init(&hba->clk_gating.delay_attr.attr);
-	hba->clk_gating.delay_attr.attr.name = "clkgate_delay_ms";
-	hba->clk_gating.delay_attr.attr.mode = 0644;
-	if (device_create_file(hba->dev, &hba->clk_gating.delay_attr))
-		dev_err(hba->dev, "Failed to create sysfs for clkgate_delay\n");
-
-	hba->clk_gating.enable_attr.show = ufshcd_clkgate_enable_show;
-	hba->clk_gating.enable_attr.store = ufshcd_clkgate_enable_store;
-	sysfs_attr_init(&hba->clk_gating.enable_attr.attr);
-	hba->clk_gating.enable_attr.attr.name = "clkgate_enable";
-	hba->clk_gating.enable_attr.attr.mode = 0644;
-	if (device_create_file(hba->dev, &hba->clk_gating.enable_attr))
-		dev_err(hba->dev, "Failed to create sysfs for clkgate_enable\n");
+	hba->clk_gating.is_enabled = true;
+	hba->clk_gating.is_initialized = true;
 }
 
 static void ufshcd_exit_clk_gating(struct ufs_hba *hba)
 {
-	if (!ufshcd_is_clkgating_allowed(hba))
+	if (!hba->clk_gating.is_initialized)
 		return;
-	device_remove_file(hba->dev, &hba->clk_gating.delay_attr);
-	device_remove_file(hba->dev, &hba->clk_gating.enable_attr);
+	ufshcd_remove_clk_gating_sysfs(hba);
 	cancel_work_sync(&hba->clk_gating.ungate_work);
 	cancel_delayed_work_sync(&hba->clk_gating.gate_work);
 	destroy_workqueue(hba->clk_gating.clk_gating_workq);
+	hba->clk_gating.is_initialized = false;
 }
 
 /* Must be called with host lock acquired */

@@ -7747,7 +7766,7 @@ static int ufshcd_add_lus(struct ufs_hba *hba)
 				goto out;
 
 			hba->clk_scaling.is_enabled = true;
-			ufshcd_clkscaling_init_sysfs(hba);
+			ufshcd_init_clk_scaling_sysfs(hba);
 		}
 	}
 

@@ -7935,7 +7954,6 @@ static void ufshcd_async_scan(void *data, async_cookie_t cookie)
 	 */
 	if (ret) {
 		pm_runtime_put_sync(hba->dev);
-		ufshcd_exit_clk_scaling(hba);
 		ufshcd_hba_exit(hba);
 	} else {
 		ufshcd_clear_ua_wluns(hba);

@@ -8365,12 +8383,12 @@ static int ufshcd_hba_init(struct ufs_hba *hba)
 static void ufshcd_hba_exit(struct ufs_hba *hba)
 {
 	if (hba->is_powered) {
+		ufshcd_exit_clk_scaling(hba);
+		ufshcd_exit_clk_gating(hba);
+		if (hba->eh_wq)
+			destroy_workqueue(hba->eh_wq);
 		ufshcd_variant_hba_exit(hba);
 		ufshcd_setup_vreg(hba, false);
-		ufshcd_suspend_clkscaling(hba);
-		if (ufshcd_is_clkscaling_supported(hba))
-			if (hba->devfreq)
-				ufshcd_suspend_clkscaling(hba);
 		ufshcd_setup_clocks(hba, false);
 		ufshcd_setup_hba_vreg(hba, false);
 		hba->is_powered = false;

@@ -9144,13 +9162,9 @@ void ufshcd_remove(struct ufs_hba *hba)
 	blk_mq_free_tag_set(&hba->tmf_tag_set);
 	blk_cleanup_queue(hba->cmd_queue);
 	scsi_remove_host(hba->host);
-	destroy_workqueue(hba->eh_wq);
 	/* disable interrupts */
 	ufshcd_disable_intr(hba, hba->intr_mask);
 	ufshcd_hba_stop(hba);
-
-	ufshcd_exit_clk_scaling(hba);
-	ufshcd_exit_clk_gating(hba);
 	ufshcd_hba_exit(hba);
 }
 EXPORT_SYMBOL_GPL(ufshcd_remove);

@@ -9351,7 +9365,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	err = devm_request_irq(dev, irq, ufshcd_intr, IRQF_SHARED, UFSHCD, hba);
 	if (err) {
 		dev_err(hba->dev, "request irq failed\n");
-		goto exit_gating;
+		goto out_disable;
 	} else {
 		hba->is_irq_enabled = true;
 	}

@@ -9359,7 +9373,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	err = scsi_add_host(host, hba->dev);
 	if (err) {
 		dev_err(hba->dev, "scsi_add_host failed\n");
-		goto exit_gating;
+		goto out_disable;
 	}
 
 	hba->cmd_queue = blk_mq_init_queue(&hba->host->tag_set);

@@ -9442,10 +9456,6 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	blk_cleanup_queue(hba->cmd_queue);
 out_remove_scsi_host:
 	scsi_remove_host(hba->host);
-exit_gating:
-	ufshcd_exit_clk_scaling(hba);
-	ufshcd_exit_clk_gating(hba);
-	destroy_workqueue(hba->eh_wq);
 out_disable:
 	hba->is_irq_enabled = false;
 	ufshcd_hba_exit(hba);
drivers/scsi/ufs/ufshcd.h +4 -0
index 2863af1..9cd76f7 100644
@@ -383,6 +383,7 @@ enum clk_gating_state {
  * @delay_attr: sysfs attribute to control delay_attr
  * @enable_attr: sysfs attribute to enable/disable clock gating
  * @is_enabled: Indicates the current status of clock gating
+ * @is_initialized: Indicates whether clock gating is initialized or not
  * @active_reqs: number of requests that are pending and should be waited for
  * completion before gating clocks.
  */

@@ -395,6 +396,7 @@ struct ufs_clk_gating {
 	struct device_attribute delay_attr;
 	struct device_attribute enable_attr;
 	bool is_enabled;
+	bool is_initialized;
 	int active_reqs;
 	struct workqueue_struct *clk_gating_workq;
 };

@@ -423,6 +425,7 @@ struct ufs_saved_pwr_info {
 		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_initialized: Indicates whether clock scaling is initialized or not
  * @is_busy_started: tracks if busy period has started or not
  * @is_suspended: tracks if devfreq is suspended or not
  */

@@ -439,6 +442,7 @@ struct ufs_clk_scaling {
 	u32 min_gear;
 	bool is_enabled;
 	bool is_allowed;
+	bool is_initialized;
 	bool is_busy_started;
 	bool is_suspended;
 };
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author
#4 lore raw

PATCH v11 3/3 scsi: ufs: Revert "Make sure clk scaling happens only when HBA is runtime ACTIVE"

In reply to Can Guo

Commit 73cc291c27024 ("Make sure clk scaling happens only when HBA is runtime ACTIVE") is no longer needed since commit 8bd22d3c50e6f ("scsi:
ufs: Protect some contexts from unexpected clock scaling") is a more mature fix to protect UFS LLD stability from clock scaling invoked through sysfs nodes by users.

Reviewed-by Stanley Chu <[email protected]>
Signed-off-by Can Guo <[email protected]>
---
 drivers/scsi/ufs/ufshcd.c | 7 -------
 1 file changed, 7 deletions(-)
drivers/scsi/ufs/ufshcd.c +0 -7
index 750cf0d..e2517d5 100644
@@ -1335,15 +1335,8 @@ static int ufshcd_devfreq_target(struct device *dev,
 	}
 	spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
 
-	pm_runtime_get_noresume(hba->dev);
-	if (!pm_runtime_active(hba->dev)) {
-		pm_runtime_put_noidle(hba->dev);
-		ret = -EAGAIN;
-		goto out;
-	}
 	start = ktime_get();
 	ret = ufshcd_devfreq_scale(hba, scale_up);
-	pm_runtime_put(hba->dev);
 
 	trace_ufshcd_profile_clk_scaling(dev_name(hba->dev),
 		(scale_up ? "up" : "down"),
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Applied
#5 lore raw
In reply to Can Guo

Can,

Quoted 10 lines

This series is made based on 5.12/scsi-queue branch.

Current devfreq framework allows sysfs nodes like governor, min_freq and max_freq to be changed even after devfreq device is suspended. Meanwhile, devfreq_suspend_device() cannot/wouldn't synchronize clock scaling which has already been invoked through devfreq sysfs nodes menitioned above. It means that clock scaling invoked through these devfreq sysfs nodes can happen at any time regardless of the state of UFS host and/or device. We need to control and synchronize clock scaling in this scenario.

Applied to 5.12/scsi-staging, thanks!

Signature · 1 line
Martin K. Petersen	Oracle Linux Engineering
Applied
#6 lore raw
In reply to Can Guo
Quoted 8 lines · Can Guo

This series is made based on 5.12/scsi-queue branch.

Current devfreq framework allows sysfs nodes like governor, min_freq and max_freq to be changed even after devfreq device is suspended. Meanwhile, devfreq_suspend_device() cannot/wouldn't synchronize clock scaling which has already been invoked through devfreq sysfs nodes menitioned above. It means that clock scaling invoked through these devfreq sysfs nodes can happen at any time regardless of the state of UFS host and/or device. We need to control and synchronize clock scaling in this scenario.

[...]

Applied to 5.12/scsi-queue, thanks!

[1/3] scsi: ufs: Protect some contexts from unexpected clock scaling

      https://git.kernel.org/mkp/scsi/c/0e9d4ca43ba8
[2/3] scsi: ufs: Refactor ufshcd_init/exit_clk_scaling/gating()
      https://git.kernel.org/mkp/scsi/c/4543d9d78227
[3/3] scsi: ufs: Revert "Make sure clk scaling happens only when HBA is runtime ACTIVE"
      https://git.kernel.org/mkp/scsi/c/b02d51afca00
Signature · 1 line
Martin K. Petersen	Oracle Linux Engineering