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Message-ID: <5331559186b4ecf5e5ffc1bf1d28c6b3@codeaurora.org>
Date: Wed, 04 Nov 2020 16:29:29 +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
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?
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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