[PATCH V2 0/1] scsi: ufs: Add support for Auto-Hibernate Idle Timer

[PATCH V2 0/1] scsi: ufs: Add support for Auto-Hibernate Idle Timer

[Adrian Hunter]

Hi

Here is V2, now re-based on top of patch "scsi: ufs: sysfs:reworking of the
rpm_lvl and spm_lvl entries".

Michał Potomski has previously sent a patch for Auto-Hibernate, but this
patch is slightly different, based on the latest ufs-sysfs changes, it also
takes care to restore auto-hibernate during resume, and otherwise avoids
updating the register if the device is runtime suspended.  Also a default
value of 150ms is set.


Changes in V2:

	Re-based on top of (yet to be applied) patch "scsi: ufs: sysfs:
	reworking of the rpm_lvl and spm_lvl entries"


Adrian Hunter (1):
      scsi: ufs: Add support for Auto-Hibernate Idle Timer

 Documentation/ABI/testing/sysfs-driver-ufs | 15 ++++++
 drivers/scsi/ufs/ufs-sysfs.c               | 77 ++++++++++++++++++++++++++++++
 drivers/scsi/ufs/ufshcd.c                  | 26 ++++++++++
 drivers/scsi/ufs/ufshcd.h                  |  3 ++
 drivers/scsi/ufs/ufshci.h                  |  7 +++
 5 files changed, 128 insertions(+)


Regards
Adrian

[PATCH V2 1/1] scsi: ufs: Add support for Auto-Hibernate Idle Timer

[Adrian Hunter]

UFS host controllers may support an autonomous power management feature
called the Auto-Hibernate Idle Timer. The timer is set to the number of
microseconds of idle time before the UFS host controller will autonomously
put the link into Hibernate state. That will save power at the expense of
increased latency. Any access to the host controller interface registers
will automatically put the link out of Hibernate state. So once configured,
the feature is transparent to the driver.

Expose the Auto-Hibernate Idle Timer value via SysFS to allow users to
choose between power efficiency or lower latency. Set a default value of
150 ms.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 Documentation/ABI/testing/sysfs-driver-ufs | 15 ++++++
 drivers/scsi/ufs/ufs-sysfs.c               | 77 ++++++++++++++++++++++++++++++
 drivers/scsi/ufs/ufshcd.c                  | 26 ++++++++++
 drivers/scsi/ufs/ufshcd.h                  |  3 ++
 drivers/scsi/ufs/ufshci.h                  |  7 +++
 5 files changed, 128 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-driver-ufs b/Documentation/ABI/testing/sysfs-driver-ufs
index 83735f79e572..a4142329cc34 100644
--- a/Documentation/ABI/testing/sysfs-driver-ufs
+++ b/Documentation/ABI/testing/sysfs-driver-ufs
@@ -1,3 +1,18 @@
+What:		/sys/bus/*/drivers/ufshcd/*/auto_hibern8
+Date:		February 2018
+Contact:	linux-scsi@vger.kernel.org
+Description:
+		This file contains the auto-hibernate idle timer setting of a
+		UFS host controller. A value of '-1' means auto-hibernate is not
+		supported. A value of '0' means auto-hibernate is not enabled.
+		Otherwise the value is the number of microseconds of idle time
+		before the UFS host controller will autonomously put the link
+		into hibernate state. That will save power at the expense of
+		increased latency. Note that the hardware supports 10-bit values
+		with a power-of-ten multiplier which allows a maximum value of
+		102300000. Refer to the UFS Host Controller Interface
+		specification for more details.
+
 What:		/sys/bus/platform/drivers/ufshcd/*/device_descriptor/device_type
 Date:		February 2018
 Contact:	Stanislav Nijnikov <stanislav.nijnikov@wdc.com>
diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c
index 4ff9e0b7eba1..17ad661b1cb5 100644
--- a/drivers/scsi/ufs/ufs-sysfs.c
+++ b/drivers/scsi/ufs/ufs-sysfs.c
@@ -3,6 +3,7 @@
 
 #include <linux/err.h>
 #include <linux/string.h>
+#include <linux/bitfield.h>
 #include <asm/unaligned.h>
 
 #include "ufs.h"
@@ -117,12 +118,87 @@ static ssize_t spm_target_link_state_show(struct device *dev,
 				ufs_pm_lvl_states[hba->spm_lvl].link_state));
 }
 
+static void ufshcd_auto_hibern8_update(struct ufs_hba *hba, u32 ahit)
+{
+	unsigned long flags;
+
+	if (!(hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT))
+		return;
+
+	spin_lock_irqsave(hba->host->host_lock, flags);
+	if (hba->ahit == ahit)
+		goto out_unlock;
+	hba->ahit = ahit;
+	if (!pm_runtime_suspended(hba->dev))
+		ufshcd_writel(hba, hba->ahit, REG_AUTO_HIBERNATE_IDLE_TIMER);
+out_unlock:
+	spin_unlock_irqrestore(hba->host->host_lock, flags);
+}
+
+/* Convert Auto-Hibernate Idle Timer register value to microseconds */
+static int ufshcd_ahit_to_us(u32 ahit)
+{
+	int timer = FIELD_GET(UFSHCI_AHIBERN8_TIMER_MASK, ahit);
+	int scale = FIELD_GET(UFSHCI_AHIBERN8_SCALE_MASK, ahit);
+
+	for (; scale > 0; --scale)
+		timer *= UFSHCI_AHIBERN8_SCALE_FACTOR;
+
+	return timer;
+}
+
+/* Convert microseconds to Auto-Hibernate Idle Timer register value */
+static u32 ufshcd_us_to_ahit(unsigned int timer)
+{
+	unsigned int scale;
+
+	for (scale = 0; timer > UFSHCI_AHIBERN8_TIMER_MASK; ++scale)
+		timer /= UFSHCI_AHIBERN8_SCALE_FACTOR;
+
+	return FIELD_PREP(UFSHCI_AHIBERN8_TIMER_MASK, timer) |
+	       FIELD_PREP(UFSHCI_AHIBERN8_SCALE_MASK, scale);
+}
+
+static ssize_t auto_hibern8_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	struct ufs_hba *hba = dev_get_drvdata(dev);
+	int timer = -1;
+
+	if (hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT)
+		timer = ufshcd_ahit_to_us(hba->ahit);
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", timer);
+}
+
+static ssize_t auto_hibern8_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t count)
+{
+	struct ufs_hba *hba = dev_get_drvdata(dev);
+	unsigned int timer;
+
+	if (!(hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT))
+		return -EOPNOTSUPP;
+
+	if (kstrtouint(buf, 0, &timer))
+		return -EINVAL;
+
+	if (timer > UFSHCI_AHIBERN8_MAX)
+		return -EINVAL;
+
+	ufshcd_auto_hibern8_update(hba, ufshcd_us_to_ahit(timer));
+
+	return count;
+}
+
 static DEVICE_ATTR_RW(rpm_lvl);
 static DEVICE_ATTR_RO(rpm_target_dev_state);
 static DEVICE_ATTR_RO(rpm_target_link_state);
 static DEVICE_ATTR_RW(spm_lvl);
 static DEVICE_ATTR_RO(spm_target_dev_state);
 static DEVICE_ATTR_RO(spm_target_link_state);
+static DEVICE_ATTR_RW(auto_hibern8);
 
 static struct attribute *ufs_sysfs_ufshcd_attrs[] = {
 	&dev_attr_rpm_lvl.attr,
@@ -131,6 +207,7 @@ static ssize_t spm_target_link_state_show(struct device *dev,
 	&dev_attr_spm_lvl.attr,
 	&dev_attr_spm_target_dev_state.attr,
 	&dev_attr_spm_target_link_state.attr,
+	&dev_attr_auto_hibern8.attr,
 	NULL
 };
 
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 3abcd31646eb..facee2b97926 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -41,6 +41,7 @@
 #include <linux/devfreq.h>
 #include <linux/nls.h>
 #include <linux/of.h>
+#include <linux/bitfield.h>
 #include "ufshcd.h"
 #include "ufs_quirks.h"
 #include "unipro.h"
@@ -3708,6 +3709,18 @@ static int ufshcd_uic_hibern8_exit(struct ufs_hba *hba)
 	return ret;
 }
 
+static void ufshcd_auto_hibern8_enable(struct ufs_hba *hba)
+{
+	unsigned long flags;
+
+	if (!(hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT) || !hba->ahit)
+		return;
+
+	spin_lock_irqsave(hba->host->host_lock, flags);
+	ufshcd_writel(hba, hba->ahit, REG_AUTO_HIBERNATE_IDLE_TIMER);
+	spin_unlock_irqrestore(hba->host->host_lock, flags);
+}
+
  /**
  * ufshcd_init_pwr_info - setting the POR (power on reset)
  * values in hba power info
@@ -6307,6 +6320,9 @@ static int ufshcd_probe_hba(struct ufs_hba *hba)
 	/* UniPro link is active now */
 	ufshcd_set_link_active(hba);
 
+	/* Enable Auto-Hibernate if configured */
+	ufshcd_auto_hibern8_enable(hba);
+
 	ret = ufshcd_verify_dev_init(hba);
 	if (ret)
 		goto out;
@@ -7391,6 +7407,10 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 
 	/* Schedule clock gating in case of no access to UFS device yet */
 	ufshcd_release(hba);
+
+	/* Enable Auto-Hibernate if configured */
+	ufshcd_auto_hibern8_enable(hba);
+
 	goto out;
 
 set_old_link_state:
@@ -7834,6 +7854,12 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 						UFS_SLEEP_PWR_MODE,
 						UIC_LINK_HIBERN8_STATE);
 
+	/* Set the default auto-hiberate idle timer value to 150 ms */
+	if (hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT) {
+		hba->ahit = FIELD_PREP(UFSHCI_AHIBERN8_TIMER_MASK, 150) |
+			    FIELD_PREP(UFSHCI_AHIBERN8_SCALE_MASK, 3);
+	}
+
 	/* Hold auto suspend until async scan completes */
 	pm_runtime_get_sync(dev);
 
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index deb3c5d382e9..8110dcd04d22 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -531,6 +531,9 @@ struct ufs_hba {
 	struct device_attribute spm_lvl_attr;
 	int pm_op_in_progress;
 
+	/* Auto-Hibernate Idle Timer register value */
+	u32 ahit;
+
 	struct ufshcd_lrb *lrb;
 	unsigned long lrb_in_use;
 
diff --git a/drivers/scsi/ufs/ufshci.h b/drivers/scsi/ufs/ufshci.h
index 1a1b5d9fe514..bb5d9c7f3353 100644
--- a/drivers/scsi/ufs/ufshci.h
+++ b/drivers/scsi/ufs/ufshci.h
@@ -86,6 +86,7 @@ enum {
 enum {
 	MASK_TRANSFER_REQUESTS_SLOTS		= 0x0000001F,
 	MASK_TASK_MANAGEMENT_REQUEST_SLOTS	= 0x00070000,
+	MASK_AUTO_HIBERN8_SUPPORT		= 0x00800000,
 	MASK_64_ADDRESSING_SUPPORT		= 0x01000000,
 	MASK_OUT_OF_ORDER_DATA_DELIVERY_SUPPORT	= 0x02000000,
 	MASK_UIC_DME_TEST_MODE_SUPPORT		= 0x04000000,
@@ -119,6 +120,12 @@ enum {
 #define MANUFACTURE_ID_MASK	UFS_MASK(0xFFFF, 0)
 #define PRODUCT_ID_MASK		UFS_MASK(0xFFFF, 16)
 
+/* AHIT - Auto-Hibernate Idle Timer */
+#define UFSHCI_AHIBERN8_TIMER_MASK		GENMASK(9, 0)
+#define UFSHCI_AHIBERN8_SCALE_MASK		GENMASK(12, 10)
+#define UFSHCI_AHIBERN8_SCALE_FACTOR		10
+#define UFSHCI_AHIBERN8_MAX			(1023 * 100000)
+
 /*
  * IS - Interrupt Status - 20h
  */
-- 
1.9.1

RE: [PATCH V2 1/1] scsi: ufs: Add support for Auto-Hibernate Idle Timer

[Stanislav Nijnikov]

> -----Original Message-----
> From: Adrian Hunter [mailto:adrian.hunter@intel.com]
> Sent: Monday, March 19, 2018 10:01 AM
> To: Vinayak Holikatti <vinholikatti@gmail.com>; Martin K. Petersen
> <martin.petersen@oracle.com>; James E.J. Bottomley
> <jejb@linux.vnet.ibm.com>
> Cc: Stanislav Nijnikov <Stanislav.Nijnikov@wdc.com>; Jaegeuk Kim
> <jaegeuk@kernel.org>; Bart Van Assche <Bart.VanAssche@wdc.com>; linux-
> scsi@vger.kernel.org; linux-kernel@vger.kernel.org; Szymon Mielczarek
> <szymonx.mielczarek@intel.com>; Alim Akhtar
> <alim.akhtar@samsung.com>; Alex Lemberg <Alex.Lemberg@wdc.com>;
> Vivek Gautam <vivek.gautam@codeaurora.org>
> Subject: [PATCH V2 1/1] scsi: ufs: Add support for Auto-Hibernate Idle Timer
> 
> UFS host controllers may support an autonomous power management
> feature called the Auto-Hibernate Idle Timer. The timer is set to the number
> of microseconds of idle time before the UFS host controller will
> autonomously put the link into Hibernate state. That will save power at the
> expense of increased latency. Any access to the host controller interface
> registers will automatically put the link out of Hibernate state. So once
> configured, the feature is transparent to the driver.
> 
> Expose the Auto-Hibernate Idle Timer value via SysFS to allow users to
> choose between power efficiency or lower latency. Set a default value of
> 150 ms.
> 
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> ---
>  Documentation/ABI/testing/sysfs-driver-ufs | 15 ++++++
>  drivers/scsi/ufs/ufs-sysfs.c               | 77
> ++++++++++++++++++++++++++++++
>  drivers/scsi/ufs/ufshcd.c                  | 26 ++++++++++
>  drivers/scsi/ufs/ufshcd.h                  |  3 ++
>  drivers/scsi/ufs/ufshci.h                  |  7 +++
>  5 files changed, 128 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-driver-ufs
> b/Documentation/ABI/testing/sysfs-driver-ufs
> index 83735f79e572..a4142329cc34 100644
> --- a/Documentation/ABI/testing/sysfs-driver-ufs
> +++ b/Documentation/ABI/testing/sysfs-driver-ufs
> @@ -1,3 +1,18 @@
> +What:		/sys/bus/*/drivers/ufshcd/*/auto_hibern8
> +Date:		February 2018
> +Contact:	linux-scsi@vger.kernel.org
> +Description:
> +		This file contains the auto-hibernate idle timer setting of a
> +		UFS host controller. A value of '-1' means auto-hibernate is
> not
> +		supported. A value of '0' means auto-hibernate is not
> enabled.
> +		Otherwise the value is the number of microseconds of idle
> time
> +		before the UFS host controller will autonomously put the link
> +		into hibernate state. That will save power at the expense of
> +		increased latency. Note that the hardware supports 10-bit
> values
> +		with a power-of-ten multiplier which allows a maximum
> value of
> +		102300000. Refer to the UFS Host Controller Interface
> +		specification for more details.
> +
>  What:
> 	/sys/bus/platform/drivers/ufshcd/*/device_descriptor/device_type
>  Date:		February 2018
>  Contact:	Stanislav Nijnikov <stanislav.nijnikov@wdc.com>
> diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c index
> 4ff9e0b7eba1..17ad661b1cb5 100644
> --- a/drivers/scsi/ufs/ufs-sysfs.c
> +++ b/drivers/scsi/ufs/ufs-sysfs.c
> @@ -3,6 +3,7 @@
> 
>  #include <linux/err.h>
>  #include <linux/string.h>
> +#include <linux/bitfield.h>
>  #include <asm/unaligned.h>
> 
>  #include "ufs.h"
> @@ -117,12 +118,87 @@ static ssize_t spm_target_link_state_show(struct
> device *dev,
>  				ufs_pm_lvl_states[hba-
> >spm_lvl].link_state));
>  }
> 
> +static void ufshcd_auto_hibern8_update(struct ufs_hba *hba, u32 ahit) {
> +	unsigned long flags;
> +
> +	if (!(hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT))
> +		return;
> +
> +	spin_lock_irqsave(hba->host->host_lock, flags);
> +	if (hba->ahit == ahit)
> +		goto out_unlock;
> +	hba->ahit = ahit;
> +	if (!pm_runtime_suspended(hba->dev))
> +		ufshcd_writel(hba, hba->ahit,
> REG_AUTO_HIBERNATE_IDLE_TIMER);
> +out_unlock:
> +	spin_unlock_irqrestore(hba->host->host_lock, flags); }
> +
> +/* Convert Auto-Hibernate Idle Timer register value to microseconds */
> +static int ufshcd_ahit_to_us(u32 ahit) {
> +	int timer = FIELD_GET(UFSHCI_AHIBERN8_TIMER_MASK, ahit);
> +	int scale = FIELD_GET(UFSHCI_AHIBERN8_SCALE_MASK, ahit);
> +
> +	for (; scale > 0; --scale)
> +		timer *= UFSHCI_AHIBERN8_SCALE_FACTOR;
> +
> +	return timer;
> +}
> +
> +/* Convert microseconds to Auto-Hibernate Idle Timer register value */
> +static u32 ufshcd_us_to_ahit(unsigned int timer) {
> +	unsigned int scale;
> +
> +	for (scale = 0; timer > UFSHCI_AHIBERN8_TIMER_MASK; ++scale)
> +		timer /= UFSHCI_AHIBERN8_SCALE_FACTOR;
> +
> +	return FIELD_PREP(UFSHCI_AHIBERN8_TIMER_MASK, timer) |
> +	       FIELD_PREP(UFSHCI_AHIBERN8_SCALE_MASK, scale); }
> +
> +static ssize_t auto_hibern8_show(struct device *dev,
> +				 struct device_attribute *attr, char *buf) {
> +	struct ufs_hba *hba = dev_get_drvdata(dev);
> +	int timer = -1;
> +
> +	if (hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT)
> +		timer = ufshcd_ahit_to_us(hba->ahit);
I think it's better to return EOPNOTSUPP when the feature is not supported than to show "-1".
> +
> +	return snprintf(buf, PAGE_SIZE, "%d\n", timer); }
> +
> +static ssize_t auto_hibern8_store(struct device *dev,
> +				  struct device_attribute *attr,
> +				  const char *buf, size_t count)
> +{
> +	struct ufs_hba *hba = dev_get_drvdata(dev);
> +	unsigned int timer;
> +
> +	if (!(hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT))
> +		return -EOPNOTSUPP;
> +
> +	if (kstrtouint(buf, 0, &timer))
> +		return -EINVAL;
> +
> +	if (timer > UFSHCI_AHIBERN8_MAX)
> +		return -EINVAL;
> +
> +	ufshcd_auto_hibern8_update(hba, ufshcd_us_to_ahit(timer));
> +
> +	return count;
> +}
> +
>  static DEVICE_ATTR_RW(rpm_lvl);
>  static DEVICE_ATTR_RO(rpm_target_dev_state);
>  static DEVICE_ATTR_RO(rpm_target_link_state);
>  static DEVICE_ATTR_RW(spm_lvl);
>  static DEVICE_ATTR_RO(spm_target_dev_state);
>  static DEVICE_ATTR_RO(spm_target_link_state);
> +static DEVICE_ATTR_RW(auto_hibern8);
> 
>  static struct attribute *ufs_sysfs_ufshcd_attrs[] = {
>  	&dev_attr_rpm_lvl.attr,
> @@ -131,6 +207,7 @@ static ssize_t spm_target_link_state_show(struct
> device *dev,
>  	&dev_attr_spm_lvl.attr,
>  	&dev_attr_spm_target_dev_state.attr,
>  	&dev_attr_spm_target_link_state.attr,
> +	&dev_attr_auto_hibern8.attr,
>  	NULL
>  };
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index
> 3abcd31646eb..facee2b97926 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -41,6 +41,7 @@
>  #include <linux/devfreq.h>
>  #include <linux/nls.h>
>  #include <linux/of.h>
> +#include <linux/bitfield.h>
>  #include "ufshcd.h"
>  #include "ufs_quirks.h"
>  #include "unipro.h"
> @@ -3708,6 +3709,18 @@ static int ufshcd_uic_hibern8_exit(struct ufs_hba
> *hba)
>  	return ret;
>  }
> 
> +static void ufshcd_auto_hibern8_enable(struct ufs_hba *hba) {
> +	unsigned long flags;
> +
> +	if (!(hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT) || !hba-
> >ahit)
> +		return;
> +
> +	spin_lock_irqsave(hba->host->host_lock, flags);
> +	ufshcd_writel(hba, hba->ahit, REG_AUTO_HIBERNATE_IDLE_TIMER);
> +	spin_unlock_irqrestore(hba->host->host_lock, flags); }
> +
>   /**
>   * ufshcd_init_pwr_info - setting the POR (power on reset)
>   * values in hba power info
> @@ -6307,6 +6320,9 @@ static int ufshcd_probe_hba(struct ufs_hba *hba)
>  	/* UniPro link is active now */
>  	ufshcd_set_link_active(hba);
> 
> +	/* Enable Auto-Hibernate if configured */
> +	ufshcd_auto_hibern8_enable(hba);
> +
>  	ret = ufshcd_verify_dev_init(hba);
>  	if (ret)
>  		goto out;
> @@ -7391,6 +7407,10 @@ static int ufshcd_resume(struct ufs_hba *hba,
> enum ufs_pm_op pm_op)
> 
>  	/* Schedule clock gating in case of no access to UFS device yet */
>  	ufshcd_release(hba);
> +
> +	/* Enable Auto-Hibernate if configured */
> +	ufshcd_auto_hibern8_enable(hba);
> +
>  	goto out;
> 
>  set_old_link_state:
> @@ -7834,6 +7854,12 @@ int ufshcd_init(struct ufs_hba *hba, void
> __iomem *mmio_base, unsigned int irq)
>  						UFS_SLEEP_PWR_MODE,
>  						UIC_LINK_HIBERN8_STATE);
> 
> +	/* Set the default auto-hiberate idle timer value to 150 ms */
> +	if (hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT) {
> +		hba->ahit = FIELD_PREP(UFSHCI_AHIBERN8_TIMER_MASK,
> 150) |
> +			    FIELD_PREP(UFSHCI_AHIBERN8_SCALE_MASK, 3);
> +	}
> +
>  	/* Hold auto suspend until async scan completes */
>  	pm_runtime_get_sync(dev);
> 
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h index
> deb3c5d382e9..8110dcd04d22 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -531,6 +531,9 @@ struct ufs_hba {
>  	struct device_attribute spm_lvl_attr;
>  	int pm_op_in_progress;
> 
> +	/* Auto-Hibernate Idle Timer register value */
> +	u32 ahit;
> +
>  	struct ufshcd_lrb *lrb;
>  	unsigned long lrb_in_use;
> 
> diff --git a/drivers/scsi/ufs/ufshci.h b/drivers/scsi/ufs/ufshci.h index
> 1a1b5d9fe514..bb5d9c7f3353 100644
> --- a/drivers/scsi/ufs/ufshci.h
> +++ b/drivers/scsi/ufs/ufshci.h
> @@ -86,6 +86,7 @@ enum {
>  enum {
>  	MASK_TRANSFER_REQUESTS_SLOTS		= 0x0000001F,
>  	MASK_TASK_MANAGEMENT_REQUEST_SLOTS	= 0x00070000,
> +	MASK_AUTO_HIBERN8_SUPPORT		= 0x00800000,
>  	MASK_64_ADDRESSING_SUPPORT		= 0x01000000,
>  	MASK_OUT_OF_ORDER_DATA_DELIVERY_SUPPORT	= 0x02000000,
>  	MASK_UIC_DME_TEST_MODE_SUPPORT		= 0x04000000,
> @@ -119,6 +120,12 @@ enum {
>  #define MANUFACTURE_ID_MASK	UFS_MASK(0xFFFF, 0)
>  #define PRODUCT_ID_MASK		UFS_MASK(0xFFFF, 16)
> 
> +/* AHIT - Auto-Hibernate Idle Timer */
> +#define UFSHCI_AHIBERN8_TIMER_MASK		GENMASK(9, 0)
> +#define UFSHCI_AHIBERN8_SCALE_MASK		GENMASK(12, 10)
> +#define UFSHCI_AHIBERN8_SCALE_FACTOR		10
> +#define UFSHCI_AHIBERN8_MAX			(1023 * 100000)
> +
>  /*
>   * IS - Interrupt Status - 20h
>   */
> --
> 1.9.1
Please fix all checkpatch errors.
Regards
Stas

Re: [PATCH V2 1/1] scsi: ufs: Add support for Auto-Hibernate Idle Timer

[Adrian Hunter]

On 20/03/18 13:56, Stanislav Nijnikov wrote:
> 
> 
>> -----Original Message-----
>> From: Adrian Hunter [mailto:adrian.hunter@intel.com]
>> Sent: Monday, March 19, 2018 10:01 AM
>> To: Vinayak Holikatti <vinholikatti@gmail.com>; Martin K. Petersen
>> <martin.petersen@oracle.com>; James E.J. Bottomley
>> <jejb@linux.vnet.ibm.com>
>> Cc: Stanislav Nijnikov <Stanislav.Nijnikov@wdc.com>; Jaegeuk Kim
>> <jaegeuk@kernel.org>; Bart Van Assche <Bart.VanAssche@wdc.com>; linux-
>> scsi@vger.kernel.org; linux-kernel@vger.kernel.org; Szymon Mielczarek
>> <szymonx.mielczarek@intel.com>; Alim Akhtar
>> <alim.akhtar@samsung.com>; Alex Lemberg <Alex.Lemberg@wdc.com>;
>> Vivek Gautam <vivek.gautam@codeaurora.org>
>> Subject: [PATCH V2 1/1] scsi: ufs: Add support for Auto-Hibernate Idle Timer
>>
>> UFS host controllers may support an autonomous power management
>> feature called the Auto-Hibernate Idle Timer. The timer is set to the number
>> of microseconds of idle time before the UFS host controller will
>> autonomously put the link into Hibernate state. That will save power at the
>> expense of increased latency. Any access to the host controller interface
>> registers will automatically put the link out of Hibernate state. So once
>> configured, the feature is transparent to the driver.
>>
>> Expose the Auto-Hibernate Idle Timer value via SysFS to allow users to
>> choose between power efficiency or lower latency. Set a default value of
>> 150 ms.
>>
>> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
>> ---
>>  Documentation/ABI/testing/sysfs-driver-ufs | 15 ++++++
>>  drivers/scsi/ufs/ufs-sysfs.c               | 77
>> ++++++++++++++++++++++++++++++
>>  drivers/scsi/ufs/ufshcd.c                  | 26 ++++++++++
>>  drivers/scsi/ufs/ufshcd.h                  |  3 ++
>>  drivers/scsi/ufs/ufshci.h                  |  7 +++
>>  5 files changed, 128 insertions(+)
>>
>> diff --git a/Documentation/ABI/testing/sysfs-driver-ufs
>> b/Documentation/ABI/testing/sysfs-driver-ufs
>> index 83735f79e572..a4142329cc34 100644
>> --- a/Documentation/ABI/testing/sysfs-driver-ufs
>> +++ b/Documentation/ABI/testing/sysfs-driver-ufs
>> @@ -1,3 +1,18 @@
>> +What:		/sys/bus/*/drivers/ufshcd/*/auto_hibern8
>> +Date:		February 2018
>> +Contact:	linux-scsi@vger.kernel.org
>> +Description:
>> +		This file contains the auto-hibernate idle timer setting of a
>> +		UFS host controller. A value of '-1' means auto-hibernate is
>> not
>> +		supported. A value of '0' means auto-hibernate is not
>> enabled.
>> +		Otherwise the value is the number of microseconds of idle
>> time
>> +		before the UFS host controller will autonomously put the link
>> +		into hibernate state. That will save power at the expense of
>> +		increased latency. Note that the hardware supports 10-bit
>> values
>> +		with a power-of-ten multiplier which allows a maximum
>> value of
>> +		102300000. Refer to the UFS Host Controller Interface
>> +		specification for more details.
>> +
>>  What:
>> 	/sys/bus/platform/drivers/ufshcd/*/device_descriptor/device_type
>>  Date:		February 2018
>>  Contact:	Stanislav Nijnikov <stanislav.nijnikov@wdc.com>
>> diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c index
>> 4ff9e0b7eba1..17ad661b1cb5 100644
>> --- a/drivers/scsi/ufs/ufs-sysfs.c
>> +++ b/drivers/scsi/ufs/ufs-sysfs.c
>> @@ -3,6 +3,7 @@
>>
>>  #include <linux/err.h>
>>  #include <linux/string.h>
>> +#include <linux/bitfield.h>
>>  #include <asm/unaligned.h>
>>
>>  #include "ufs.h"
>> @@ -117,12 +118,87 @@ static ssize_t spm_target_link_state_show(struct
>> device *dev,
>>  				ufs_pm_lvl_states[hba-
>>> spm_lvl].link_state));
>>  }
>>
>> +static void ufshcd_auto_hibern8_update(struct ufs_hba *hba, u32 ahit) {
>> +	unsigned long flags;
>> +
>> +	if (!(hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT))
>> +		return;
>> +
>> +	spin_lock_irqsave(hba->host->host_lock, flags);
>> +	if (hba->ahit == ahit)
>> +		goto out_unlock;
>> +	hba->ahit = ahit;
>> +	if (!pm_runtime_suspended(hba->dev))
>> +		ufshcd_writel(hba, hba->ahit,
>> REG_AUTO_HIBERNATE_IDLE_TIMER);
>> +out_unlock:
>> +	spin_unlock_irqrestore(hba->host->host_lock, flags); }
>> +
>> +/* Convert Auto-Hibernate Idle Timer register value to microseconds */
>> +static int ufshcd_ahit_to_us(u32 ahit) {
>> +	int timer = FIELD_GET(UFSHCI_AHIBERN8_TIMER_MASK, ahit);
>> +	int scale = FIELD_GET(UFSHCI_AHIBERN8_SCALE_MASK, ahit);
>> +
>> +	for (; scale > 0; --scale)
>> +		timer *= UFSHCI_AHIBERN8_SCALE_FACTOR;
>> +
>> +	return timer;
>> +}
>> +
>> +/* Convert microseconds to Auto-Hibernate Idle Timer register value */
>> +static u32 ufshcd_us_to_ahit(unsigned int timer) {
>> +	unsigned int scale;
>> +
>> +	for (scale = 0; timer > UFSHCI_AHIBERN8_TIMER_MASK; ++scale)
>> +		timer /= UFSHCI_AHIBERN8_SCALE_FACTOR;
>> +
>> +	return FIELD_PREP(UFSHCI_AHIBERN8_TIMER_MASK, timer) |
>> +	       FIELD_PREP(UFSHCI_AHIBERN8_SCALE_MASK, scale); }
>> +
>> +static ssize_t auto_hibern8_show(struct device *dev,
>> +				 struct device_attribute *attr, char *buf) {
>> +	struct ufs_hba *hba = dev_get_drvdata(dev);
>> +	int timer = -1;
>> +
>> +	if (hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT)
>> +		timer = ufshcd_ahit_to_us(hba->ahit);
> I think it's better to return EOPNOTSUPP when the feature is not supported than to show "-1".

OK

>> +
>> +	return snprintf(buf, PAGE_SIZE, "%d\n", timer); }
>> +
>> +static ssize_t auto_hibern8_store(struct device *dev,
>> +				  struct device_attribute *attr,
>> +				  const char *buf, size_t count)
>> +{
>> +	struct ufs_hba *hba = dev_get_drvdata(dev);
>> +	unsigned int timer;
>> +
>> +	if (!(hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT))
>> +		return -EOPNOTSUPP;
>> +
>> +	if (kstrtouint(buf, 0, &timer))
>> +		return -EINVAL;
>> +
>> +	if (timer > UFSHCI_AHIBERN8_MAX)
>> +		return -EINVAL;
>> +
>> +	ufshcd_auto_hibern8_update(hba, ufshcd_us_to_ahit(timer));
>> +
>> +	return count;
>> +}
>> +
>>  static DEVICE_ATTR_RW(rpm_lvl);
>>  static DEVICE_ATTR_RO(rpm_target_dev_state);
>>  static DEVICE_ATTR_RO(rpm_target_link_state);
>>  static DEVICE_ATTR_RW(spm_lvl);
>>  static DEVICE_ATTR_RO(spm_target_dev_state);
>>  static DEVICE_ATTR_RO(spm_target_link_state);
>> +static DEVICE_ATTR_RW(auto_hibern8);
>>
>>  static struct attribute *ufs_sysfs_ufshcd_attrs[] = {
>>  	&dev_attr_rpm_lvl.attr,
>> @@ -131,6 +207,7 @@ static ssize_t spm_target_link_state_show(struct
>> device *dev,
>>  	&dev_attr_spm_lvl.attr,
>>  	&dev_attr_spm_target_dev_state.attr,
>>  	&dev_attr_spm_target_link_state.attr,
>> +	&dev_attr_auto_hibern8.attr,
>>  	NULL
>>  };
>>
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index
>> 3abcd31646eb..facee2b97926 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -41,6 +41,7 @@
>>  #include <linux/devfreq.h>
>>  #include <linux/nls.h>
>>  #include <linux/of.h>
>> +#include <linux/bitfield.h>
>>  #include "ufshcd.h"
>>  #include "ufs_quirks.h"
>>  #include "unipro.h"
>> @@ -3708,6 +3709,18 @@ static int ufshcd_uic_hibern8_exit(struct ufs_hba
>> *hba)
>>  	return ret;
>>  }
>>
>> +static void ufshcd_auto_hibern8_enable(struct ufs_hba *hba) {
>> +	unsigned long flags;
>> +
>> +	if (!(hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT) || !hba-
>>> ahit)
>> +		return;
>> +
>> +	spin_lock_irqsave(hba->host->host_lock, flags);
>> +	ufshcd_writel(hba, hba->ahit, REG_AUTO_HIBERNATE_IDLE_TIMER);
>> +	spin_unlock_irqrestore(hba->host->host_lock, flags); }
>> +
>>   /**
>>   * ufshcd_init_pwr_info - setting the POR (power on reset)
>>   * values in hba power info
>> @@ -6307,6 +6320,9 @@ static int ufshcd_probe_hba(struct ufs_hba *hba)
>>  	/* UniPro link is active now */
>>  	ufshcd_set_link_active(hba);
>>
>> +	/* Enable Auto-Hibernate if configured */
>> +	ufshcd_auto_hibern8_enable(hba);
>> +
>>  	ret = ufshcd_verify_dev_init(hba);
>>  	if (ret)
>>  		goto out;
>> @@ -7391,6 +7407,10 @@ static int ufshcd_resume(struct ufs_hba *hba,
>> enum ufs_pm_op pm_op)
>>
>>  	/* Schedule clock gating in case of no access to UFS device yet */
>>  	ufshcd_release(hba);
>> +
>> +	/* Enable Auto-Hibernate if configured */
>> +	ufshcd_auto_hibern8_enable(hba);
>> +
>>  	goto out;
>>
>>  set_old_link_state:
>> @@ -7834,6 +7854,12 @@ int ufshcd_init(struct ufs_hba *hba, void
>> __iomem *mmio_base, unsigned int irq)
>>  						UFS_SLEEP_PWR_MODE,
>>  						UIC_LINK_HIBERN8_STATE);
>>
>> +	/* Set the default auto-hiberate idle timer value to 150 ms */
>> +	if (hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT) {
>> +		hba->ahit = FIELD_PREP(UFSHCI_AHIBERN8_TIMER_MASK,
>> 150) |
>> +			    FIELD_PREP(UFSHCI_AHIBERN8_SCALE_MASK, 3);
>> +	}
>> +
>>  	/* Hold auto suspend until async scan completes */
>>  	pm_runtime_get_sync(dev);
>>
>> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h index
>> deb3c5d382e9..8110dcd04d22 100644
>> --- a/drivers/scsi/ufs/ufshcd.h
>> +++ b/drivers/scsi/ufs/ufshcd.h
>> @@ -531,6 +531,9 @@ struct ufs_hba {
>>  	struct device_attribute spm_lvl_attr;
>>  	int pm_op_in_progress;
>>
>> +	/* Auto-Hibernate Idle Timer register value */
>> +	u32 ahit;
>> +
>>  	struct ufshcd_lrb *lrb;
>>  	unsigned long lrb_in_use;
>>
>> diff --git a/drivers/scsi/ufs/ufshci.h b/drivers/scsi/ufs/ufshci.h index
>> 1a1b5d9fe514..bb5d9c7f3353 100644
>> --- a/drivers/scsi/ufs/ufshci.h
>> +++ b/drivers/scsi/ufs/ufshci.h
>> @@ -86,6 +86,7 @@ enum {
>>  enum {
>>  	MASK_TRANSFER_REQUESTS_SLOTS		= 0x0000001F,
>>  	MASK_TASK_MANAGEMENT_REQUEST_SLOTS	= 0x00070000,
>> +	MASK_AUTO_HIBERN8_SUPPORT		= 0x00800000,
>>  	MASK_64_ADDRESSING_SUPPORT		= 0x01000000,
>>  	MASK_OUT_OF_ORDER_DATA_DELIVERY_SUPPORT	= 0x02000000,
>>  	MASK_UIC_DME_TEST_MODE_SUPPORT		= 0x04000000,
>> @@ -119,6 +120,12 @@ enum {
>>  #define MANUFACTURE_ID_MASK	UFS_MASK(0xFFFF, 0)
>>  #define PRODUCT_ID_MASK		UFS_MASK(0xFFFF, 16)
>>
>> +/* AHIT - Auto-Hibernate Idle Timer */
>> +#define UFSHCI_AHIBERN8_TIMER_MASK		GENMASK(9, 0)
>> +#define UFSHCI_AHIBERN8_SCALE_MASK		GENMASK(12, 10)
>> +#define UFSHCI_AHIBERN8_SCALE_FACTOR		10
>> +#define UFSHCI_AHIBERN8_MAX			(1023 * 100000)
>> +
>>  /*
>>   * IS - Interrupt Status - 20h
>>   */
>> --
>> 1.9.1
> Please fix all checkpatch errors.

I don't get any checkpatch errors.  Can you list them?