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Message-ID: <a3b909186ff96ec29e98999590822cd1@codeaurora.org>
Date: Wed, 04 Nov 2020 17:03:43 +0800
From: Can Guo <cang@...eaurora.org>
To: Adrian Hunter <adrian.hunter@...el.com>
Cc: "Martin K . Petersen" <martin.petersen@...cle.com>,
"James E . J . Bottomley" <jejb@...ux.ibm.com>,
linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org,
Alim Akhtar <alim.akhtar@...sung.com>,
Avri Altman <avri.altman@....com>,
Bean Huo <huobean@...il.com>,
Stanley Chu <stanley.chu@...iatek.com>
Subject: Re: [PATCH V4 1/2] scsi: ufs: Add DeepSleep feature
On 2020-11-04 16:37, Adrian Hunter wrote:
> On 4/11/20 10:29 am, Can Guo wrote:
>> Hi Adrian,
>>
>> On 2020-11-03 22:14, Adrian Hunter wrote:
>>> DeepSleep is a UFS v3.1 feature that achieves the lowest power
>>> consumption
>>> of the device, apart from power off.
>>>
>>> In DeepSleep mode, no commands are accepted, and the only way to exit
>>> is
>>> using a hardware reset or power cycle.
>>>
>>> This patch assumes that if a power cycle was an option, then power
>>> off
>>> would be preferable, so only exit via a hardware reset is supported.
>>>
>>> Drivers that wish to support DeepSleep need to set a new capability
>>> flag
>>> UFSHCD_CAP_DEEPSLEEP and provide a hardware reset via the existing
>>> ->device_reset() callback.
>>>
>>> It is assumed that UFS devices with wspecversion >= 0x310 support
>>> DeepSleep.
>>>
>>> Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
>>> ---
>>> Documentation/ABI/testing/sysfs-driver-ufs | 34 +++++++++++--------
>>> drivers/scsi/ufs/ufs-sysfs.c | 7 ++++
>>> drivers/scsi/ufs/ufs.h | 1 +
>>> drivers/scsi/ufs/ufshcd.c | 39
>>> ++++++++++++++++++++--
>>> drivers/scsi/ufs/ufshcd.h | 17 +++++++++-
>>> include/trace/events/ufs.h | 3 +-
>>> 6 files changed, 83 insertions(+), 18 deletions(-)
>>>
>>> diff --git a/Documentation/ABI/testing/sysfs-driver-ufs
>>> b/Documentation/ABI/testing/sysfs-driver-ufs
>>> index adc0d0e91607..e77fa784d6d8 100644
>>> --- a/Documentation/ABI/testing/sysfs-driver-ufs
>>> +++ b/Documentation/ABI/testing/sysfs-driver-ufs
>>> @@ -916,21 +916,24 @@ Date: September 2014
>>> Contact: Subhash Jadavani <subhashj@...eaurora.org>
>>> Description: This entry could be used to set or show the UFS
>>> device
>>> runtime power management level. The current driver
>>> - implementation supports 6 levels with next target states:
>>> + implementation supports 7 levels with next target states:
>>>
>>> == ====================================================
>>> - 0 an UFS device will stay active, an UIC link will
>>> + 0 UFS device will stay active, UIC link will
>>> stay active
>>> - 1 an UFS device will stay active, an UIC link will
>>> + 1 UFS device will stay active, UIC link will
>>> hibernate
>>> - 2 an UFS device will moved to sleep, an UIC link will
>>> + 2 UFS device will be moved to sleep, UIC link will
>>> stay active
>>> - 3 an UFS device will moved to sleep, an UIC link will
>>> + 3 UFS device will be moved to sleep, UIC link will
>>> hibernate
>>> - 4 an UFS device will be powered off, an UIC link will
>>> + 4 UFS device will be powered off, UIC link will
>>> hibernate
>>> - 5 an UFS device will be powered off, an UIC link will
>>> + 5 UFS device will be powered off, UIC link will
>>> be powered off
>>> + 6 UFS device will be moved to deep sleep, UIC link
>>> + will be powered off. Note, deep sleep might not be
>>> + supported in which case this value will not be accepted
>>
>> Nitpicking, usually higher spm/rpm_lvl means better power saving.
>> Since POWERDOWN+LINKOFF achieves the lowest power consumption, can
>> we put DEEPSLEEP_LINKOFF to 5, and POWERDOWN_LINKOFF to 6?
>
> That would break the API i.e. we shouldn't change the meaning of '5'
>
> Also, pedantically it depends on whether regulators are provided as to
> whether Deep Sleep is higher/lower than PowerDown i.e. without
> regulators to
> switch off the device, it will remain in PowerDown mode which does not
> save
> as much power as Deep Sleep.
>
OK, that makes sense. The change LGTM, I gave my reivewed-by tag.
Regards,
Can Guo.
>>
>> Thanks,
>>
>> Can Guo.
>>
>>> == ====================================================
>>>
>>> What: /sys/bus/platform/drivers/ufshcd/*/rpm_target_dev_state
>>> @@ -954,21 +957,24 @@ Date: September 2014
>>> Contact: Subhash Jadavani <subhashj@...eaurora.org>
>>> Description: This entry could be used to set or show the UFS
>>> device
>>> system power management level. The current driver
>>> - implementation supports 6 levels with next target states:
>>> + implementation supports 7 levels with next target states:
>>>
>>> == ====================================================
>>> - 0 an UFS device will stay active, an UIC link will
>>> + 0 UFS device will stay active, UIC link will
>>> stay active
>>> - 1 an UFS device will stay active, an UIC link will
>>> + 1 UFS device will stay active, UIC link will
>>> hibernate
>>> - 2 an UFS device will moved to sleep, an UIC link will
>>> + 2 UFS device will be moved to sleep, UIC link will
>>> stay active
>>> - 3 an UFS device will moved to sleep, an UIC link will
>>> + 3 UFS device will be moved to sleep, UIC link will
>>> hibernate
>>> - 4 an UFS device will be powered off, an UIC link will
>>> + 4 UFS device will be powered off, UIC link will
>>> hibernate
>>> - 5 an UFS device will be powered off, an UIC link will
>>> + 5 UFS device will be powered off, UIC link will
>>> be powered off
>>> + 6 UFS device will be moved to deep sleep, UIC link
>>> + will be powered off. Note, deep sleep might not be
>>> + supported in which case this value will not be accepted
>>> == ====================================================
>>>
>>> What: /sys/bus/platform/drivers/ufshcd/*/spm_target_dev_state
>>> diff --git a/drivers/scsi/ufs/ufs-sysfs.c
>>> b/drivers/scsi/ufs/ufs-sysfs.c
>>> index bdcd27faa054..08e72b7eef6a 100644
>>> --- a/drivers/scsi/ufs/ufs-sysfs.c
>>> +++ b/drivers/scsi/ufs/ufs-sysfs.c
>>> @@ -28,6 +28,7 @@ static const char
>>> *ufschd_ufs_dev_pwr_mode_to_string(
>>> case UFS_ACTIVE_PWR_MODE: return "ACTIVE";
>>> case UFS_SLEEP_PWR_MODE: return "SLEEP";
>>> case UFS_POWERDOWN_PWR_MODE: return "POWERDOWN";
>>> + case UFS_DEEPSLEEP_PWR_MODE: return "DEEPSLEEP";
>>> default: return "UNKNOWN";
>>> }
>>> }
>>> @@ -38,6 +39,7 @@ static inline ssize_t ufs_sysfs_pm_lvl_store(struct
>>> device *dev,
>>> bool rpm)
>>> {
>>> struct ufs_hba *hba = dev_get_drvdata(dev);
>>> + struct ufs_dev_info *dev_info = &hba->dev_info;
>>> unsigned long flags, value;
>>>
>>> if (kstrtoul(buf, 0, &value))
>>> @@ -46,6 +48,11 @@ static inline ssize_t
>>> ufs_sysfs_pm_lvl_store(struct
>>> device *dev,
>>> if (value >= UFS_PM_LVL_MAX)
>>> return -EINVAL;
>>>
>>> + if (ufs_pm_lvl_states[value].dev_state == UFS_DEEPSLEEP_PWR_MODE
>>> &&
>>> + (!(hba->caps & UFSHCD_CAP_DEEPSLEEP) ||
>>> + !(dev_info->wspecversion >= 0x310)))
>>> + return -EINVAL;
>>> +
>>> spin_lock_irqsave(hba->host->host_lock, flags);
>>> if (rpm)
>>> hba->rpm_lvl = value;
>>> diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h
>>> index f8ab16f30fdc..d593edb48767 100644
>>> --- a/drivers/scsi/ufs/ufs.h
>>> +++ b/drivers/scsi/ufs/ufs.h
>>> @@ -442,6 +442,7 @@ enum ufs_dev_pwr_mode {
>>> UFS_ACTIVE_PWR_MODE = 1,
>>> UFS_SLEEP_PWR_MODE = 2,
>>> UFS_POWERDOWN_PWR_MODE = 3,
>>> + UFS_DEEPSLEEP_PWR_MODE = 4,
>>> };
>>>
>>> #define UFS_WB_BUF_REMAIN_PERCENT(val) ((val) / 10)
>>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>>> index 2309253d3101..ee083b96e405 100644
>>> --- a/drivers/scsi/ufs/ufshcd.c
>>> +++ b/drivers/scsi/ufs/ufshcd.c
>>> @@ -163,6 +163,11 @@ struct ufs_pm_lvl_states ufs_pm_lvl_states[] = {
>>> {UFS_SLEEP_PWR_MODE, UIC_LINK_HIBERN8_STATE},
>>> {UFS_POWERDOWN_PWR_MODE, UIC_LINK_HIBERN8_STATE},
>>> {UFS_POWERDOWN_PWR_MODE, UIC_LINK_OFF_STATE},
>>> + /*
>>> + * For DeepSleep, the link is first put in hibern8 and then off.
>>> + * Leaving the link in hibern8 is not supported.
>>> + */
>>> + {UFS_DEEPSLEEP_PWR_MODE, UIC_LINK_OFF_STATE},
>>> };
>>>
>>> static inline enum ufs_dev_pwr_mode
>>> @@ -8297,7 +8302,8 @@ static int ufshcd_link_state_transition(struct
>>> ufs_hba *hba,
>>> }
>>> /*
>>> * If autobkops is enabled, link can't be turned off because
>>> - * turning off the link would also turn off the device.
>>> + * turning off the link would also turn off the device, except
>>> in the
>>> + * case of DeepSleep where the device is expected to remain
>>> powered.
>>> */
>>> else if ((req_link_state == UIC_LINK_OFF_STATE) &&
>>> (!check_for_bkops || !hba->auto_bkops_enabled)) {
>>> @@ -8307,6 +8313,9 @@ static int ufshcd_link_state_transition(struct
>>> ufs_hba *hba,
>>> * put the link in low power mode is to send the DME end
>>> point
>>> * to device and then send the DME reset command to local
>>> * unipro. But putting the link in hibern8 is much faster.
>>> + *
>>> + * Note also that putting the link in Hibern8 is a
>>> requirement
>>> + * for entering DeepSleep.
>>> */
>>> ret = ufshcd_uic_hibern8_enter(hba);
>>> if (ret) {
>>> @@ -8439,6 +8448,7 @@ static void ufshcd_hba_vreg_set_hpm(struct
>>> ufs_hba
>>> *hba)
>>> static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>> {
>>> int ret = 0;
>>> + int check_for_bkops;
>>> enum ufs_pm_level pm_lvl;
>>> enum ufs_dev_pwr_mode req_dev_pwr_mode;
>>> enum uic_link_state req_link_state;
>>> @@ -8524,7 +8534,13 @@ static int ufshcd_suspend(struct ufs_hba *hba,
>>> enum ufs_pm_op pm_op)
>>> }
>>>
>>> flush_work(&hba->eeh_work);
>>> - ret = ufshcd_link_state_transition(hba, req_link_state, 1);
>>> +
>>> + /*
>>> + * In the case of DeepSleep, the device is expected to remain
>>> powered
>>> + * with the link off, so do not check for bkops.
>>> + */
>>> + check_for_bkops = !ufshcd_is_ufs_dev_deepsleep(hba);
>>> + ret = ufshcd_link_state_transition(hba, req_link_state,
>>> check_for_bkops);
>>> if (ret)
>>> goto set_dev_active;
>>>
>>> @@ -8565,11 +8581,25 @@ static int ufshcd_suspend(struct ufs_hba
>>> *hba,
>>> enum ufs_pm_op pm_op)
>>> if (hba->clk_scaling.is_allowed)
>>> ufshcd_resume_clkscaling(hba);
>>> ufshcd_vreg_set_hpm(hba);
>>> + /*
>>> + * Device hardware reset is required to exit DeepSleep. Also,
>>> for
>>> + * DeepSleep, the link is off so host reset and restore will be
>>> done
>>> + * further below.
>>> + */
>>> + if (ufshcd_is_ufs_dev_deepsleep(hba)) {
>>> + ufshcd_vops_device_reset(hba);
>>> + WARN_ON(!ufshcd_is_link_off(hba));
>>> + }
>>> if (ufshcd_is_link_hibern8(hba) &&
>>> !ufshcd_uic_hibern8_exit(hba))
>>> ufshcd_set_link_active(hba);
>>> else if (ufshcd_is_link_off(hba))
>>> ufshcd_host_reset_and_restore(hba);
>>> set_dev_active:
>>> + /* Can also get here needing to exit DeepSleep */
>>> + if (ufshcd_is_ufs_dev_deepsleep(hba)) {
>>> + ufshcd_vops_device_reset(hba);
>>> + ufshcd_host_reset_and_restore(hba);
>>> + }
>>> if (!ufshcd_set_dev_pwr_mode(hba, UFS_ACTIVE_PWR_MODE))
>>> ufshcd_disable_auto_bkops(hba);
>>> enable_gating:
>>> @@ -8631,6 +8661,9 @@ static int ufshcd_resume(struct ufs_hba *hba,
>>> enum ufs_pm_op pm_op)
>>> if (ret)
>>> goto disable_vreg;
>>>
>>> + /* For DeepSleep, the only supported option is to have the link
>>> off */
>>> + WARN_ON(ufshcd_is_ufs_dev_deepsleep(hba) &&
>>> !ufshcd_is_link_off(hba));
>>> +
>>> if (ufshcd_is_link_hibern8(hba)) {
>>> ret = ufshcd_uic_hibern8_exit(hba);
>>> if (!ret) {
>>> @@ -8644,6 +8677,8 @@ static int ufshcd_resume(struct ufs_hba *hba,
>>> enum ufs_pm_op pm_op)
>>> /*
>>> * A full initialization of the host and the device is
>>> * required since the link was put to off during suspend.
>>> + * Note, in the case of DeepSleep, the device will exit
>>> + * DeepSleep due to device reset.
>>> */
>>> ret = ufshcd_reset_and_restore(hba);
>>> /*
>>> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
>>> index 0fbb735bb70c..213be0667b59 100644
>>> --- a/drivers/scsi/ufs/ufshcd.h
>>> +++ b/drivers/scsi/ufs/ufshcd.h
>>> @@ -114,16 +114,22 @@ enum uic_link_state {
>>> ((h)->curr_dev_pwr_mode = UFS_SLEEP_PWR_MODE)
>>> #define ufshcd_set_ufs_dev_poweroff(h) \
>>> ((h)->curr_dev_pwr_mode = UFS_POWERDOWN_PWR_MODE)
>>> +#define ufshcd_set_ufs_dev_deepsleep(h) \
>>> + ((h)->curr_dev_pwr_mode = UFS_DEEPSLEEP_PWR_MODE)
>>> #define ufshcd_is_ufs_dev_active(h) \
>>> ((h)->curr_dev_pwr_mode == UFS_ACTIVE_PWR_MODE)
>>> #define ufshcd_is_ufs_dev_sleep(h) \
>>> ((h)->curr_dev_pwr_mode == UFS_SLEEP_PWR_MODE)
>>> #define ufshcd_is_ufs_dev_poweroff(h) \
>>> ((h)->curr_dev_pwr_mode == UFS_POWERDOWN_PWR_MODE)
>>> +#define ufshcd_is_ufs_dev_deepsleep(h) \
>>> + ((h)->curr_dev_pwr_mode == UFS_DEEPSLEEP_PWR_MODE)
>>>
>>> /*
>>> * UFS Power management levels.
>>> - * Each level is in increasing order of power savings.
>>> + * Each level is in increasing order of power savings, except
>>> DeepSleep
>>> + * which is lower than PowerDown with power on but not PowerDown
>>> with
>>> + * power off.
>>> */
>>> enum ufs_pm_level {
>>> UFS_PM_LVL_0, /* UFS_ACTIVE_PWR_MODE, UIC_LINK_ACTIVE_STATE */
>>> @@ -132,6 +138,7 @@ enum ufs_pm_level {
>>> UFS_PM_LVL_3, /* UFS_SLEEP_PWR_MODE, UIC_LINK_HIBERN8_STATE */
>>> UFS_PM_LVL_4, /* UFS_POWERDOWN_PWR_MODE, UIC_LINK_HIBERN8_STATE
>>> */
>>> UFS_PM_LVL_5, /* UFS_POWERDOWN_PWR_MODE, UIC_LINK_OFF_STATE */
>>> + UFS_PM_LVL_6, /* UFS_DEEPSLEEP_PWR_MODE, UIC_LINK_OFF_STATE */
>>> UFS_PM_LVL_MAX
>>> };
>>>
>>> @@ -599,6 +606,14 @@ enum ufshcd_caps {
>>> * This would increase power savings.
>>> */
>>> UFSHCD_CAP_AGGR_POWER_COLLAPSE = 1 << 9,
>>> +
>>> + /*
>>> + * This capability allows the host controller driver to use
>>> DeepSleep,
>>> + * if it is supported by the UFS device. The host controller
>>> driver must
>>> + * support device hardware reset via the hba->device_reset()
>>> callback,
>>> + * in order to exit DeepSleep state.
>>> + */
>>> + UFSHCD_CAP_DEEPSLEEP = 1 << 10,
>>> };
>>>
>>> struct ufs_hba_variant_params {
>>> diff --git a/include/trace/events/ufs.h b/include/trace/events/ufs.h
>>> index 84841b3a7ffd..2362244c2a9e 100644
>>> --- a/include/trace/events/ufs.h
>>> +++ b/include/trace/events/ufs.h
>>> @@ -19,7 +19,8 @@
>>> #define UFS_PWR_MODES \
>>> EM(UFS_ACTIVE_PWR_MODE) \
>>> EM(UFS_SLEEP_PWR_MODE) \
>>> - EMe(UFS_POWERDOWN_PWR_MODE)
>>> + EM(UFS_POWERDOWN_PWR_MODE) \
>>> + EMe(UFS_DEEPSLEEP_PWR_MODE)
>>>
>>> #define UFSCHD_CLK_GATING_STATES \
>>> EM(CLKS_OFF) \
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