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Date: Mon, 19 Feb 2018 08:35:43 +0200
From: Adrian Hunter <adrian.hunter@...el.com>
To: Avri Altman <Avri.Altman@....com>,
Vinayak Holikatti <vinholikatti@...il.com>,
"Martin K. Petersen" <martin.petersen@...cle.com>,
"James E.J. Bottomley" <jejb@...ux.vnet.ibm.com>
Cc: Stanislav Nijnikov <Stanislav.Nijnikov@....com>,
Jaegeuk Kim <jaegeuk@...nel.org>,
Bart Van Assche <Bart.VanAssche@....com>,
"linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Michal Potomski <michalx.potomski@...el.com>,
Szymon Mielczarek <szymonx.mielczarek@...el.com>
Subject: Re: [PATCH 1/1] scsi: ufs: Add support for Auto-Hibernate Idle Timer
On 18/02/18 11:45, Avri Altman wrote:
>
>
>> -----Original Message-----
>> From: linux-scsi-owner@...r.kernel.org [mailto:linux-scsi-
>> owner@...r.kernel.org] On Behalf Of Adrian Hunter
>> Sent: Friday, February 16, 2018 2:01 PM
>> To: Vinayak Holikatti <vinholikatti@...il.com>; Martin K. Petersen
>> <martin.petersen@...cle.com>; James E.J. Bottomley
>> <jejb@...ux.vnet.ibm.com>
>> Cc: Stanislav Nijnikov <Stanislav.Nijnikov@....com>; Jaegeuk Kim
>> <jaegeuk@...nel.org>; Bart Van Assche <Bart.VanAssche@....com>; linux-
>> scsi@...r.kernel.org; linux-kernel@...r.kernel.org; Michal Potomski
>> <michalx.potomski@...el.com>; Szymon Mielczarek
>> <szymonx.mielczarek@...el.com>
>> Subject: [PATCH 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@...el.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 07f1c2f8dbfc..c7f9441079eb 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@...r.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@....com>
>> diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c index
>> cd7174d2d225..a0e38776dc92 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"
>> @@ -123,12 +124,88 @@ static ssize_t spm_lvl_store(struct device *dev,
>> return ufs_sysfs_pm_lvl_store(dev, attr, buf, count, false); }
>>
>> +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_RW(spm_lvl);
>> +static DEVICE_ATTR_RW(auto_hibern8);
>>
>> static struct attribute *ufs_sysfs_ufshcd_attrs[] = {
>> &dev_attr_rpm_lvl.attr,
>> &dev_attr_spm_lvl.attr,
>> + &dev_attr_auto_hibern8.attr,
>> NULL
>> };
>>
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index
>> 5d874e303d4e..d5fc2fa65495 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"
>> @@ -3709,6 +3710,18 @@ 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
>> @@ -6315,6 +6328,9 @@ 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;
>> @@ -7399,6 +7415,10 @@ 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:
>> @@ -7843,6 +7863,12 @@ 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 */
> Your commit said you are setting an idle timer in microseconds, Better use usec to avoid confusion?
As the SysFS documentation says "Note that the hardware supports 10-bit
values with a power-of-ten multiplier ... Refer to the UFS Host Controller
Interface specification for more details.", so 150,000 us is still a value
of 150 with a power-of-ten multiplier of 3.
>
>
>> + 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
>> a57d9bdebfed..763a8e6c98ee 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
>
>
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