> -----Original Message-----
> From: linux-scsi-ow...@vger.kernel.org [mailto:linux-scsi-
> ow...@vger.kernel.org] On Behalf Of Adrian Hunter
> Sent: Friday, February 16, 2018 2:01 PM
> To: Vinayak Holikatti <vinholika...@gmail.com>; Martin K. Petersen
> <martin.peter...@oracle.com>; James E.J. Bottomley
> <j...@linux.vnet.ibm.com>
> Cc: Stanislav Nijnikov <stanislav.nijni...@wdc.com>; Jaegeuk Kim
> <jaeg...@kernel.org>; Bart Van Assche <bart.vanass...@wdc.com>; linux-
> s...@vger.kernel.org; linux-ker...@vger.kernel.org; Michal Potomski
> <michalx.potom...@intel.com>; Szymon Mielczarek
> <szymonx.mielcza...@intel.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.hun...@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 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@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.nijni...@wdc.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?
> + 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
