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Commit b427411a authored by Sahitya Tummala's avatar Sahitya Tummala Committed by Martin K. Petersen
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scsi: ufs: Add sysfs node to dynamically control clock gating 



Provide an option to enable/disable clock gating during runtime.
Write 1 or 0 to "clkgate_enable" sysfs node to enable/disable
clock gating.

Signed-off-by: default avatarSahitya Tummala <stummala@codeaurora.org>
Signed-off-by: default avatarSubhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent e7d38257

drivers/scsi/ufs/ufshcd.c

+47 −1
Original line number Diff line number Diff line
@@ -970,6 +970,41 @@ static ssize_t ufshcd_clkgate_delay_store(struct device *dev, 
	return count;

}



static ssize_t ufshcd_clkgate_enable_show(struct device *dev,

		struct device_attribute *attr, char *buf)

{

	struct ufs_hba *hba = dev_get_drvdata(dev);



	return snprintf(buf, PAGE_SIZE, "%d\n", hba->clk_gating.is_enabled);

}



static ssize_t ufshcd_clkgate_enable_store(struct device *dev,

		struct device_attribute *attr, const char *buf, size_t count)

{

	struct ufs_hba *hba = dev_get_drvdata(dev);

	unsigned long flags;

	u32 value;



	if (kstrtou32(buf, 0, &value))

		return -EINVAL;



	value = !!value;

	if (value == hba->clk_gating.is_enabled)

		goto out;



	if (value) {

		ufshcd_release(hba);

	} else {

		spin_lock_irqsave(hba->host->host_lock, flags);

		hba->clk_gating.active_reqs++;

		spin_unlock_irqrestore(hba->host->host_lock, flags);

	}



	hba->clk_gating.is_enabled = value;

out:

	return count;

}



static void ufshcd_init_clk_gating(struct ufs_hba *hba)

{

	if (!ufshcd_is_clkgating_allowed(hba))
@@ -979,13 +1014,23 @@ static void ufshcd_init_clk_gating(struct ufs_hba *hba) 
	INIT_DELAYED_WORK(&hba->clk_gating.gate_work, ufshcd_gate_work);

	INIT_WORK(&hba->clk_gating.ungate_work, ufshcd_ungate_work);



	hba->clk_gating.is_enabled = true;



	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 = S_IRUGO | S_IWUSR;

	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");

}



static void ufshcd_exit_clk_gating(struct ufs_hba *hba)
@@ -993,6 +1038,7 @@ static void ufshcd_exit_clk_gating(struct ufs_hba *hba) 
	if (!ufshcd_is_clkgating_allowed(hba))

		return;

	device_remove_file(hba->dev, &hba->clk_gating.delay_attr);

	device_remove_file(hba->dev, &hba->clk_gating.enable_attr);

	cancel_work_sync(&hba->clk_gating.ungate_work);

	cancel_delayed_work_sync(&hba->clk_gating.gate_work);

}

drivers/scsi/ufs/ufshcd.h

+4 −0
Original line number Diff line number Diff line
@@ -320,6 +320,8 @@ enum clk_gating_state { 
 * @is_suspended: clk gating is suspended when set to 1 which can be used

 * during suspend/resume

 * @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

 * @active_reqs: number of requests that are pending and should be waited for

 * completion before gating clocks.

 */
@@ -330,6 +332,8 @@ struct ufs_clk_gating { 
	unsigned long delay_ms;

	bool is_suspended;

	struct device_attribute delay_attr;

	struct device_attribute enable_attr;

	bool is_enabled;

	int active_reqs;

};