Commit ad448378 authored by Adrian Hunter's avatar Adrian Hunter Committed by Martin K. Petersen
Browse files

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: default avatarAdrian Hunter <adrian.hunter@intel.com>
Acked-by: default avatarStanislav Nijnikov <stanislav.nijnikov@wdc.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 114c1aa2

Documentation/ABI/testing/sysfs-driver-ufs

+14 −0
Original line number Diff line number Diff line 
What:		/sys/bus/*/drivers/ufshcd/*/auto_hibern8

Date:		March 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 '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>

drivers/scsi/ufs/ufs-sysfs.c

+76 −0
Original line number Diff line number Diff line
@@ -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 +118,86 @@ 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);



	if (!(hba->capabilities & MASK_AUTO_HIBERN8_SUPPORT))

		return -EOPNOTSUPP;



	return snprintf(buf, PAGE_SIZE, "%d\n", ufshcd_ahit_to_us(hba->ahit));

}



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 +206,7 @@ static struct attribute *ufs_sysfs_ufshcd_attrs[] = { 
	&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

};

drivers/scsi/ufs/ufshcd.c

+26 −0
Original line number Diff line number Diff line
@@ -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);

drivers/scsi/ufs/ufshcd.h

+3 −0
Original line number Diff line number Diff line
@@ -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;

drivers/scsi/ufs/ufshci.h

+7 −0
Original line number Diff line number Diff line
@@ -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

 */

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