Re: [PATCH v12 1/2] scsi: ufs: Enable power management for wlun

Adrian Hunter
2021-03-23T06:13:13Z

On 22/03/21 9:53 pm, Asutosh Das (asd) wrote:
> On 3/19/2021 10:47 AM, Adrian Hunter wrote:
>> On 19/03/21 2:35 am, Asutosh Das wrote:
>>> During runtime-suspend of ufs host, the scsi devices are
>>> already suspended and so are the queues associated with them.
>>> But the ufs host sends SSU to wlun during its runtime-suspend.
>>> During the process blk_queue_enter checks if the queue is not in
>>> suspended state. If so, it waits for the queue to resume, and never
>>> comes out of it.
>>> The commit
>>> (d55d15a33: scsi: block: Do not accept any requests while suspended)
>>> adds the check if the queue is in suspended state in blk_queue_enter().
>>>
>>> Call trace:
>>>   __switch_to+0x174/0x2c4
>>>   __schedule+0x478/0x764
>>>   schedule+0x9c/0xe0
>>>   blk_queue_enter+0x158/0x228
>>>   blk_mq_alloc_request+0x40/0xa4
>>>   blk_get_request+0x2c/0x70
>>>   __scsi_execute+0x60/0x1c4
>>>   ufshcd_set_dev_pwr_mode+0x124/0x1e4
>>>   ufshcd_suspend+0x208/0x83c
>>>   ufshcd_runtime_suspend+0x40/0x154
>>>   ufshcd_pltfrm_runtime_suspend+0x14/0x20
>>>   pm_generic_runtime_suspend+0x28/0x3c
>>>   __rpm_callback+0x80/0x2a4
>>>   rpm_suspend+0x308/0x614
>>>   rpm_idle+0x158/0x228
>>>   pm_runtime_work+0x84/0xac
>>>   process_one_work+0x1f0/0x470
>>>   worker_thread+0x26c/0x4c8
>>>   kthread+0x13c/0x320
>>>   ret_from_fork+0x10/0x18
>>>
>>> Fix this by registering ufs device wlun as a scsi driver and
>>> registering it for block runtime-pm. Also make this as a
>>> supplier for all other luns. That way, this device wlun
>>> suspends after all the consumers and resumes after
>>> hba resumes.
>>>
>>> Co-developed-by: Can Guo <cang@codeaurora.org>
>>> Signed-off-by: Can Guo <cang@codeaurora.org>
>>> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
>>
>> I have some more comments that may help straighten things out.
>>
>> Also please look at ufs_debugfs_get_user_access() and
>> ufs_debugfs_put_user_access() that now need to scsi_autopm_get/put_device
>> sdev_ufs_device.
>>
>> It would also be good if you could re-base on linux-next.
>>
>
> Hi Adrian
> Thanks for the comments.
>
> I agree moving the code to wlun probe and other changes.
> But it looks to me that it may not fully solve the issue.
>
> Please let me explain my understanding on this:
>
> (Please refer to the logs in v10)
> scsi_autopm_*() are invoked on a sdev.
> pm_runtime_get_suppliers()/rpm_put_suppliers() are on the supplier device.
>
> For the device wlun:
>     slave_configure():
>         - doesn't set the rpm_autosuspend
>         - pm_runtime_getnoresume()
>     scsi_sysfs_add_sdev():
>         - pm_runtime_forbid()
>         - scsi_autopm_get_device()
>         - device_add()
>             - ufshcd_wl_probe()
>         - scsi_autopm_put_device()
>
> For all other scsi devices:
>     slave_alloc():
>         - ufshcd_setup_links()
> Say all link_add: pm_runtime_put(&hba->sdev_ufs_device->sdev_gendev);

With DL_FLAG_RPM_ACTIVE, links will 'get' not 'put'

>     slave_configure():
>         - set rpm_autosuspend
>     scsi_sysfs_add_sdev():
>         - scsi_autopm_get_device()
>         - device_add() -> schedules an async probe()
>         - scsi_autopm_put_device() - (1)
>
> Now the rpm_put_suppliers() can be invoked *after* pm_runtime_get_suppliers() of the async probe(), since both are running in different contexts.

Only if the sd device suspends.

> In that case, the usage_count of supplier would be decremented until rpm_active of this link becomes 1.

Right, because the sd device suspended.

> Now the pm_runtime_get_suppliers() expects the link_active to be more than 1.

Not sure what you mean here. pm_runtime_*put*_suppliers() won't do anything if the link count is 1.

> Now then, there comes a time, that when sd_probe() schedules a suspend, the supplier usage_count becomes 0 and the link_active becomes 1.
> And the supplier suspends before the consumer.

sd probe first resumes the sd device which will resume the supplier.

>
> So I was wondering, what'd make sure that the pm_runtime_get_suppliers() from driver_probe_device() is invoked after scsi_autopm_put_device() (1) finishes the rpm_put_suppliers().
>
> Am not sure if I'm missing something in this.
> Do you think, the current changes alone can fix the above issue?

Yes, but let's see.

>
> -asd
>
>>> ---
>>>   drivers/scsi/ufs/cdns-pltfrm.c     |   2 +
>>>   drivers/scsi/ufs/tc-dwc-g210-pci.c |   2 +
>>>   drivers/scsi/ufs/ufs-debugfs.c     |   2 +-
>>>   drivers/scsi/ufs/ufs-debugfs.h     |   2 +-
>>>   drivers/scsi/ufs/ufs-exynos.c      |   2 +
>>>   drivers/scsi/ufs/ufs-hisi.c        |   2 +
>>>   drivers/scsi/ufs/ufs-mediatek.c    |  12 +-
>>>   drivers/scsi/ufs/ufs-qcom.c        |   2 +
>>>   drivers/scsi/ufs/ufs_bsg.c         |   6 +-
>>>   drivers/scsi/ufs/ufshcd-pci.c      |  36 +--
>>>   drivers/scsi/ufs/ufshcd.c          | 622 ++++++++++++++++++++++++++-----------
>>>   drivers/scsi/ufs/ufshcd.h          |   6 +
>>>   include/trace/events/ufs.h         |  20 ++
>>>   13 files changed, 491 insertions(+), 225 deletions(-)
>>>
>>> diff --git a/drivers/scsi/ufs/cdns-pltfrm.c b/drivers/scsi/ufs/cdns-pltfrm.c
>>> index 149391f..3e70c23 100644
>>> --- a/drivers/scsi/ufs/cdns-pltfrm.c
>>> +++ b/drivers/scsi/ufs/cdns-pltfrm.c
>>> @@ -319,6 +319,8 @@ static const struct dev_pm_ops cdns_ufs_dev_pm_ops = {
>>>       .runtime_suspend = ufshcd_pltfrm_runtime_suspend,
>>>       .runtime_resume  = ufshcd_pltfrm_runtime_resume,
>>>       .runtime_idle    = ufshcd_pltfrm_runtime_idle,
>>> +    .prepare     = ufshcd_suspend_prepare,
>>> +    .complete    = ufshcd_resume_complete,
>>>   };
>>>     static struct platform_driver cdns_ufs_pltfrm_driver = {
>>> diff --git a/drivers/scsi/ufs/tc-dwc-g210-pci.c b/drivers/scsi/ufs/tc-dwc-g210-pci.c
>>> index 67a6a61..b01db12 100644
>>> --- a/drivers/scsi/ufs/tc-dwc-g210-pci.c
>>> +++ b/drivers/scsi/ufs/tc-dwc-g210-pci.c
>>> @@ -148,6 +148,8 @@ static const struct dev_pm_ops tc_dwc_g210_pci_pm_ops = {
>>>       .runtime_suspend = tc_dwc_g210_pci_runtime_suspend,
>>>       .runtime_resume  = tc_dwc_g210_pci_runtime_resume,
>>>       .runtime_idle    = tc_dwc_g210_pci_runtime_idle,
>>> +    .prepare     = ufshcd_suspend_prepare,
>>> +    .complete    = ufshcd_resume_complete,
>>>   };
>>>     static const struct pci_device_id tc_dwc_g210_pci_tbl[] = {
>>> diff --git a/drivers/scsi/ufs/ufs-debugfs.c b/drivers/scsi/ufs/ufs-debugfs.c
>>> index dee98dc..06457d5 100644
>>> --- a/drivers/scsi/ufs/ufs-debugfs.c
>>> +++ b/drivers/scsi/ufs/ufs-debugfs.c
>>> @@ -13,7 +13,7 @@ void __init ufs_debugfs_init(void)
>>>       ufs_debugfs_root = debugfs_create_dir("ufshcd", NULL);
>>>   }
>>>   -void __exit ufs_debugfs_exit(void)
>>> +void ufs_debugfs_exit(void)
>>>   {
>>>       debugfs_remove_recursive(ufs_debugfs_root);
>>>   }
>>> diff --git a/drivers/scsi/ufs/ufs-debugfs.h b/drivers/scsi/ufs/ufs-debugfs.h
>>> index f35b39c..12c2730 100644
>>> --- a/drivers/scsi/ufs/ufs-debugfs.h
>>> +++ b/drivers/scsi/ufs/ufs-debugfs.h
>>> @@ -9,7 +9,7 @@ struct ufs_hba;
>>>     #ifdef CONFIG_DEBUG_FS
>>>   void __init ufs_debugfs_init(void);
>>> -void __exit ufs_debugfs_exit(void);
>>> +void ufs_debugfs_exit(void);
>>>   void ufs_debugfs_hba_init(struct ufs_hba *hba);
>>>   void ufs_debugfs_hba_exit(struct ufs_hba *hba);
>>>   #else
>>> diff --git a/drivers/scsi/ufs/ufs-exynos.c b/drivers/scsi/ufs/ufs-exynos.c
>>> index 267943a1..45c0b02 100644
>>> --- a/drivers/scsi/ufs/ufs-exynos.c
>>> +++ b/drivers/scsi/ufs/ufs-exynos.c
>>> @@ -1268,6 +1268,8 @@ static const struct dev_pm_ops exynos_ufs_pm_ops = {
>>>       .runtime_suspend = ufshcd_pltfrm_runtime_suspend,
>>>       .runtime_resume  = ufshcd_pltfrm_runtime_resume,
>>>       .runtime_idle    = ufshcd_pltfrm_runtime_idle,
>>> +    .prepare     = ufshcd_suspend_prepare,
>>> +    .complete    = ufshcd_resume_complete,
>>>   };
>>>     static struct platform_driver exynos_ufs_pltform = {
>>> diff --git a/drivers/scsi/ufs/ufs-hisi.c b/drivers/scsi/ufs/ufs-hisi.c
>>> index 0aa5813..d463b44 100644
>>> --- a/drivers/scsi/ufs/ufs-hisi.c
>>> +++ b/drivers/scsi/ufs/ufs-hisi.c
>>> @@ -574,6 +574,8 @@ static const struct dev_pm_ops ufs_hisi_pm_ops = {
>>>       .runtime_suspend = ufshcd_pltfrm_runtime_suspend,
>>>       .runtime_resume  = ufshcd_pltfrm_runtime_resume,
>>>       .runtime_idle    = ufshcd_pltfrm_runtime_idle,
>>> +    .prepare     = ufshcd_suspend_prepare,
>>> +    .complete    = ufshcd_resume_complete,
>>>   };
>>>     static struct platform_driver ufs_hisi_pltform = {
>>> diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
>>> index c55202b..51c82e3 100644
>>> --- a/drivers/scsi/ufs/ufs-mediatek.c
>>> +++ b/drivers/scsi/ufs/ufs-mediatek.c
>>> @@ -810,12 +810,10 @@ static int ufs_mtk_post_link(struct ufs_hba *hba)
>>>       /* enable unipro clock gating feature */
>>>       ufs_mtk_cfg_unipro_cg(hba, true);
>>>   -    /* configure auto-hibern8 timer to 10ms */
>>> -    if (ufshcd_is_auto_hibern8_supported(hba)) {
>>> -        ufshcd_auto_hibern8_update(hba,
>>> -            FIELD_PREP(UFSHCI_AHIBERN8_TIMER_MASK, 10) |
>>> -            FIELD_PREP(UFSHCI_AHIBERN8_SCALE_MASK, 3));
>>> -    }
>>> +    /* will be configured during probe hba */
>>> +    if (ufshcd_is_auto_hibern8_supported(hba))
>>> +        hba->ahit = FIELD_PREP(UFSHCI_AHIBERN8_TIMER_MASK, 10) |
>>> +            FIELD_PREP(UFSHCI_AHIBERN8_SCALE_MASK, 3);
>>>         ufs_mtk_setup_clk_gating(hba);
>>>   @@ -1097,6 +1095,8 @@ static const struct dev_pm_ops ufs_mtk_pm_ops = {
>>>       .runtime_suspend = ufshcd_pltfrm_runtime_suspend,
>>>       .runtime_resume  = ufshcd_pltfrm_runtime_resume,
>>>       .runtime_idle    = ufshcd_pltfrm_runtime_idle,
>>> +    .prepare     = ufshcd_suspend_prepare,
>>> +    .complete    = ufshcd_resume_complete,
>>>   };
>>>     static struct platform_driver ufs_mtk_pltform = {
>>> diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
>>> index f97d7b0..9aa098a 100644
>>> --- a/drivers/scsi/ufs/ufs-qcom.c
>>> +++ b/drivers/scsi/ufs/ufs-qcom.c
>>> @@ -1546,6 +1546,8 @@ static const struct dev_pm_ops ufs_qcom_pm_ops = {
>>>       .runtime_suspend = ufshcd_pltfrm_runtime_suspend,
>>>       .runtime_resume  = ufshcd_pltfrm_runtime_resume,
>>>       .runtime_idle    = ufshcd_pltfrm_runtime_idle,
>>> +    .prepare     = ufshcd_suspend_prepare,
>>> +    .complete    = ufshcd_resume_complete,
>>>   };
>>>     static struct platform_driver ufs_qcom_pltform = {
>>> diff --git a/drivers/scsi/ufs/ufs_bsg.c b/drivers/scsi/ufs/ufs_bsg.c
>>> index 5b2bc1a..cbb5a90 100644
>>> --- a/drivers/scsi/ufs/ufs_bsg.c
>>> +++ b/drivers/scsi/ufs/ufs_bsg.c
>>> @@ -97,7 +97,7 @@ static int ufs_bsg_request(struct bsg_job *job)
>>>         bsg_reply->reply_payload_rcv_len = 0;
>>>   -    pm_runtime_get_sync(hba->dev);
>>> +    scsi_autopm_get_device(hba->sdev_ufs_device);
>>>         msgcode = bsg_request->msgcode;
>>>       switch (msgcode) {
>>> @@ -106,7 +106,7 @@ static int ufs_bsg_request(struct bsg_job *job)
>>>           ret = ufs_bsg_alloc_desc_buffer(hba, job, &desc_buff,
>>>                           &desc_len, desc_op);
>>>           if (ret) {
>>> -            pm_runtime_put_sync(hba->dev);
>>> +            scsi_autopm_put_device(hba->sdev_ufs_device);
>>>               goto out;
>>>           }
>>>   @@ -138,7 +138,7 @@ static int ufs_bsg_request(struct bsg_job *job)
>>>           break;
>>>       }
>>>   -    pm_runtime_put_sync(hba->dev);
>>> +    scsi_autopm_put_device(hba->sdev_ufs_device);
>>>         if (!desc_buff)
>>>           goto out;
>>> diff --git a/drivers/scsi/ufs/ufshcd-pci.c b/drivers/scsi/ufs/ufshcd-pci.c
>>> index fadd566..5d4ffd2 100644
>>> --- a/drivers/scsi/ufs/ufshcd-pci.c
>>> +++ b/drivers/scsi/ufs/ufshcd-pci.c
>>> @@ -247,29 +247,6 @@ static int ufshcd_pci_resume(struct device *dev)
>>>       return ufshcd_system_resume(dev_get_drvdata(dev));
>>>   }
>>>   -/**
>>> - * ufshcd_pci_poweroff - suspend-to-disk poweroff function
>>> - * @dev: pointer to PCI device handle
>>> - *
>>> - * Returns 0 if successful
>>> - * Returns non-zero otherwise
>>> - */
>>> -static int ufshcd_pci_poweroff(struct device *dev)
>>> -{
>>> -    struct ufs_hba *hba = dev_get_drvdata(dev);
>>> -    int spm_lvl = hba->spm_lvl;
>>> -    int ret;
>>> -
>>> -    /*
>>> -     * For poweroff we need to set the UFS device to PowerDown mode.
>>> -     * Force spm_lvl to ensure that.
>>> -     */
>>> -    hba->spm_lvl = 5;
>>> -    ret = ufshcd_system_suspend(hba);
>>> -    hba->spm_lvl = spm_lvl;
>>> -    return ret;
>>> -}
>>> -
>>>   #endif /* !CONFIG_PM_SLEEP */
>>>     #ifdef CONFIG_PM
>>> @@ -365,17 +342,14 @@ ufshcd_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>>>   }
>>>     static const struct dev_pm_ops ufshcd_pci_pm_ops = {
>>> -#ifdef CONFIG_PM_SLEEP
>>> -    .suspend    = ufshcd_pci_suspend,
>>> -    .resume        = ufshcd_pci_resume,
>>> -    .freeze        = ufshcd_pci_suspend,
>>> -    .thaw        = ufshcd_pci_resume,
>>> -    .poweroff    = ufshcd_pci_poweroff,
>>> -    .restore    = ufshcd_pci_resume,
>>> -#endif
>>>       SET_RUNTIME_PM_OPS(ufshcd_pci_runtime_suspend,
>>>                  ufshcd_pci_runtime_resume,
>>>                  ufshcd_pci_runtime_idle)
>>> +    SET_SYSTEM_SLEEP_PM_OPS(ufshcd_pci_suspend, ufshcd_pci_resume)
>>> +#ifdef CONFIG_PM_SLEEP
>>> +    .prepare    = ufshcd_suspend_prepare,
>>> +    .complete    = ufshcd_resume_complete,
>>> +#endif
>>>   };
>>>     static const struct pci_device_id ufshcd_pci_tbl[] = {
>>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>>> index 45624c7..7106cb8 100644
>>> --- a/drivers/scsi/ufs/ufshcd.c
>>> +++ b/drivers/scsi/ufs/ufshcd.c
>>> @@ -16,6 +16,7 @@
>>>   #include <linux/bitfield.h>
>>>   #include <linux/blk-pm.h>
>>>   #include <linux/blkdev.h>
>>> +#include <scsi/scsi_driver.h>
>>>   #include "ufshcd.h"
>>>   #include "ufs_quirks.h"
>>>   #include "unipro.h"
>>> @@ -78,6 +79,8 @@
>>>   /* Polling time to wait for fDeviceInit */
>>>   #define FDEVICEINIT_COMPL_TIMEOUT 1500 /* millisecs */
>>>   +#define wlun_dev_to_hba(dv) shost_priv(to_scsi_device(dv)->host)
>>> +
>>>   #define ufshcd_toggle_vreg(_dev, _vreg, _on)                \
>>>       ({                                                              \
>>>           int _ret;                                               \
>>> @@ -1556,7 +1559,7 @@ static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
>>>       if (value == hba->clk_scaling.is_enabled)
>>>           goto out;
>>>   -    pm_runtime_get_sync(hba->dev);
>>> +    scsi_autopm_get_device(hba->sdev_ufs_device);
>>>       ufshcd_hold(hba, false);
>>>         hba->clk_scaling.is_enabled = value;
>>> @@ -1572,7 +1575,7 @@ static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
>>>       }
>>>         ufshcd_release(hba);
>>> -    pm_runtime_put_sync(hba->dev);
>>> +    scsi_autopm_put_device(hba->sdev_ufs_device);
>>>   out:
>>>       up(&hba->host_sem);
>>>       return err ? err : count;
>>> @@ -2572,6 +2575,17 @@ static inline u16 ufshcd_upiu_wlun_to_scsi_wlun(u8 upiu_wlun_id)
>>>       return (upiu_wlun_id & ~UFS_UPIU_WLUN_ID) | SCSI_W_LUN_BASE;
>>>   }
>>>   +static inline bool is_rpmb_wlun(struct scsi_device *sdev)
>>> +{
>>> +    return (sdev->lun == ufshcd_upiu_wlun_to_scsi_wlun(UFS_UPIU_RPMB_WLUN));
>>> +}
>>> +
>>> +static inline bool is_device_wlun(struct scsi_device *sdev)
>>> +{
>>> +    return (sdev->lun ==
>>> +        ufshcd_upiu_wlun_to_scsi_wlun(UFS_UPIU_UFS_DEVICE_WLUN));
>>> +}
>>> +
>>>   static void ufshcd_init_lrb(struct ufs_hba *hba, struct ufshcd_lrb *lrb, int i)
>>>   {
>>>       struct utp_transfer_cmd_desc *cmd_descp = hba->ucdl_base_addr;
>>> @@ -4106,11 +4120,11 @@ void ufshcd_auto_hibern8_update(struct ufs_hba *hba, u32 ahit)
>>>       spin_unlock_irqrestore(hba->host->host_lock, flags);
>>>         if (update && !pm_runtime_suspended(hba->dev)) {
>>> -        pm_runtime_get_sync(hba->dev);
>>> +        scsi_autopm_get_device(hba->sdev_ufs_device);
>>>           ufshcd_hold(hba, false);
>>>           ufshcd_auto_hibern8_enable(hba);
>>>           ufshcd_release(hba);
>>> -        pm_runtime_put(hba->dev);
>>> +        scsi_autopm_put_device(hba->sdev_ufs_device);
>>>       }
>>>   }
>>>   EXPORT_SYMBOL_GPL(ufshcd_auto_hibern8_update);
>>> @@ -4808,6 +4822,41 @@ static inline void ufshcd_get_lu_power_on_wp_status(struct ufs_hba *hba,
>>>   }
>>>     /**
>>> + * ufshcd_setup_links - associate link b/w device wlun and other luns
>>> + * @sdev: pointer to SCSI device
>>> + * @hba: pointer to ufs hba
>>> + */
>>> +static void ufshcd_setup_links(struct ufs_hba *hba, struct scsi_device *sdev)
>>> +{
>>> +    struct device_link *link;
>>> +
>>> +    /*
>>> +     * device wlun is the supplier & rest of the luns are consumers
>>> +     * This ensures that device wlun suspends after all other luns.
>>> +     */
>>> +    if (hba->sdev_ufs_device) {
>>> +        link = device_link_add(&sdev->sdev_gendev,
>>> +                       &hba->sdev_ufs_device->sdev_gendev,
>>> +                       DL_FLAG_PM_RUNTIME|DL_FLAG_RPM_ACTIVE);
>>> +        if (!link) {
>>> +            dev_err(&sdev->sdev_gendev, "Failed establishing link - %s\n",
>>> +                dev_name(&hba->sdev_ufs_device->sdev_gendev));
>>> +            return;
>>> +        }
>>> +        hba->luns_avail--;
>>> +        /* Ignore REPORT_LUN wlun probing */
>>> +        if (hba->luns_avail != 1) {
>>
>> The condition here is the wrong way around. i.e. should be
>>
>>         if (hba->luns_avail == 1) {
>>
>>> +            pm_runtime_put_noidle(&hba->sdev_ufs_device->sdev_gendev);
>>
>> If the usage_count is zero here, then we should let it suspend i.e. make this:
>>
>>             pm_runtime_put(&hba->sdev_ufs_device->sdev_gendev);
>>
>> Note this pairs with the pm_runtime_get_noresume() that needs to be added
>> to ufshcd_slave_configure.  Please see comments for ufshcd_slave_configure().
>>
>>
>>> +            pm_runtime_allow(&hba->sdev_ufs_device->sdev_gendev);
>>
>> This pm_runtime_allow should not be here.  It should be in ufshcd_wl_probe().
>> Please see comments for ufshcd_wl_probe().
>>
>>> +            return;
>>> +        }
>>> +    } else {
>>> +        /* device wlun is probed */
>>> +        hba->luns_avail--;
>>> +    }
>>> +}
>>> +
>>> +/**
>>>    * ufshcd_slave_alloc - handle initial SCSI device configurations
>>>    * @sdev: pointer to SCSI device
>>>    *
>>> @@ -4838,6 +4887,8 @@ static int ufshcd_slave_alloc(struct scsi_device *sdev)
>>>         ufshcd_get_lu_power_on_wp_status(hba, sdev);
>>>   +    ufshcd_setup_links(hba, sdev);
>>> +
>>>       return 0;
>>>   }
>>>   @@ -4869,8 +4920,13 @@ static int ufshcd_slave_configure(struct scsi_device *sdev)
>>>       blk_queue_update_dma_pad(q, PRDT_DATA_BYTE_COUNT_PAD - 1);
>>>       if (hba->quirks & UFSHCD_QUIRK_ALIGN_SG_WITH_PAGE_SIZE)
>>>           blk_queue_update_dma_alignment(q, PAGE_SIZE - 1);
>>> -
>>> -    if (ufshcd_is_rpm_autosuspend_allowed(hba))
>>> +    /*
>>> +     * Block runtime-pm until all consumers are added.
>>> +     * Refer ufshcd_setup_links().
>>> +     */
>>> +    if (is_device_wlun(sdev))
>>> +        pm_runtime_forbid(&sdev->sdev_gendev);
>>
>> Since rpm_autosuspend is not being set for sdev_ufs_device, scsi_sysfs_add_sdev()
>> will pm_runtime_forbid() it anyway.  We should increase the usage_count instead
>> i.e.
>>
>>         pm_runtime_get_noresume(&sdev->sdev_gendev);
>>
>>> +    else if (ufshcd_is_rpm_autosuspend_allowed(hba))
>>>           sdev->rpm_autosuspend = 1;
>>>         ufshcd_crypto_setup_rq_keyslot_manager(hba, q);
>>> @@ -4985,15 +5041,9 @@ ufshcd_transfer_rsp_status(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
>>>                * UFS device needs urgent BKOPs.
>>>                */
>>>               if (!hba->pm_op_in_progress &&
>>> -                ufshcd_is_exception_event(lrbp->ucd_rsp_ptr) &&
>>> -                schedule_work(&hba->eeh_work)) {
>>> -                /*
>>> -                 * Prevent suspend once eeh_work is scheduled
>>> -                 * to avoid deadlock between ufshcd_suspend
>>> -                 * and exception event handler.
>>> -                 */
>>> -                pm_runtime_get_noresume(hba->dev);
>>> -            }
>>> +                ufshcd_is_exception_event(lrbp->ucd_rsp_ptr))
>>> +                /* Flushed in suspend */
>>> +                schedule_work(&hba->eeh_work);
>>>               break;
>>>           case UPIU_TRANSACTION_REJECT_UPIU:
>>>               /* TODO: handle Reject UPIU Response */
>>> @@ -5589,8 +5639,8 @@ static void ufshcd_rpm_dev_flush_recheck_work(struct work_struct *work)
>>>        * after a certain delay to recheck the threshold by next runtime
>>>        * suspend.
>>>        */
>>> -    pm_runtime_get_sync(hba->dev);
>>> -    pm_runtime_put_sync(hba->dev);
>>> +    scsi_autopm_get_device(hba->sdev_ufs_device);
>>> +    scsi_autopm_put_device(hba->sdev_ufs_device);
>>>   }
>>>     /**
>>> @@ -5607,7 +5657,6 @@ static void ufshcd_exception_event_handler(struct work_struct *work)
>>>       u32 status = 0;
>>>       hba = container_of(work, struct ufs_hba, eeh_work);
>>>   -    pm_runtime_get_sync(hba->dev);
>>>       ufshcd_scsi_block_requests(hba);
>>>       err = ufshcd_get_ee_status(hba, &status);
>>>       if (err) {
>>> @@ -5623,14 +5672,6 @@ static void ufshcd_exception_event_handler(struct work_struct *work)
>>>     out:
>>>       ufshcd_scsi_unblock_requests(hba);
>>> -    /*
>>> -     * pm_runtime_get_noresume is called while scheduling
>>> -     * eeh_work to avoid suspend racing with exception work.
>>> -     * Hence decrement usage counter using pm_runtime_put_noidle
>>> -     * to allow suspend on completion of exception event handler.
>>> -     */
>>> -    pm_runtime_put_noidle(hba->dev);
>>> -    pm_runtime_put(hba->dev);
>>>       return;
>>>   }
>>>   @@ -5755,12 +5796,13 @@ static void ufshcd_clk_scaling_suspend(struct ufs_hba *hba, bool suspend)
>>>     static void ufshcd_err_handling_prepare(struct ufs_hba *hba)
>>>   {
>>> -    pm_runtime_get_sync(hba->dev);
>>> -    if (pm_runtime_status_suspended(hba->dev) || hba->is_sys_suspended) {
>>> +    scsi_autopm_get_device(hba->sdev_ufs_device);
>>> +    if (pm_runtime_status_suspended(&hba->sdev_ufs_device->sdev_gendev) ||
>>> +        hba->is_sys_suspended) {
>>>           enum ufs_pm_op pm_op;
>>>             /*
>>> -         * Don't assume anything of pm_runtime_get_sync(), if
>>> +         * Don't assume anything of resume, if
>>>            * resume fails, irq and clocks can be OFF, and powers
>>>            * can be OFF or in LPM.
>>>            */
>>> @@ -5789,7 +5831,7 @@ static void ufshcd_err_handling_unprepare(struct ufs_hba *hba)
>>>       ufshcd_release(hba);
>>>       if (ufshcd_is_clkscaling_supported(hba))
>>>           ufshcd_clk_scaling_suspend(hba, false);
>>> -    pm_runtime_put(hba->dev);
>>> +    pm_runtime_put(&hba->sdev_ufs_device->sdev_gendev);
>>>   }
>>>     static inline bool ufshcd_err_handling_should_stop(struct ufs_hba *hba)
>>> @@ -5810,14 +5852,14 @@ static void ufshcd_recover_pm_error(struct ufs_hba *hba)
>>>         hba->is_sys_suspended = false;
>>>       /*
>>> -     * Set RPM status of hba device to RPM_ACTIVE,
>>> +     * Set RPM status of wlun device to RPM_ACTIVE,
>>>        * this also clears its runtime error.
>>>        */
>>> -    ret = pm_runtime_set_active(hba->dev);
>>> +    ret = pm_runtime_set_active(&hba->sdev_ufs_device->sdev_gendev);
>>>       /*
>>> -     * If hba device had runtime error, we also need to resume those
>>> -     * scsi devices under hba in case any of them has failed to be
>>> -     * resumed due to hba runtime resume failure. This is to unblock
>>> +     * If wlun device had runtime error, we also need to resume those
>>> +     * consumer scsi devices in case any of them has failed to be
>>> +     * resumed due to supplier runtime resume failure. This is to unblock
>>>        * blk_queue_enter in case there are bios waiting inside it.
>>>        */
>>>       if (!ret) {
>>> @@ -7207,11 +7249,12 @@ static void ufshcd_set_active_icc_lvl(struct ufs_hba *hba)
>>>     static inline void ufshcd_blk_pm_runtime_init(struct scsi_device *sdev)
>>>   {
>>> +    int dly = is_device_wlun(sdev) ? 0:RPM_AUTOSUSPEND_DELAY_MS;
>>> +
>>>       scsi_autopm_get_device(sdev);
>>>       blk_pm_runtime_init(sdev->request_queue, &sdev->sdev_gendev);
>>>       if (sdev->rpm_autosuspend)
>>> -        pm_runtime_set_autosuspend_delay(&sdev->sdev_gendev,
>>> -                         RPM_AUTOSUSPEND_DELAY_MS);
>>> +        pm_runtime_set_autosuspend_delay(&sdev->sdev_gendev, dly);
>>>       scsi_autopm_put_device(sdev);
>>>   }
>>>   @@ -7253,6 +7296,7 @@ static int ufshcd_scsi_add_wlus(struct ufs_hba *hba)
>>>           hba->sdev_ufs_device = NULL;
>>>           goto out;
>>>       }
>>> +    scsi_autopm_get_device(hba->sdev_ufs_device);
>>>       ufshcd_blk_pm_runtime_init(hba->sdev_ufs_device);
>>
>> Let's drop both scsi_autopm_get_device() and ufshcd_blk_pm_runtime_init()
>> here and instead do things in ufshcd_wl_probe() - see comments for ufshcd_wl_probe()
>>
>>>       scsi_device_put(hba->sdev_ufs_device);
>>>   @@ -7417,6 +7461,9 @@ static int ufs_get_device_desc(struct ufs_hba *hba)
>>>           goto out;
>>>       }
>>>   +    hba->luns_avail = desc_buf[DEVICE_DESC_PARAM_NUM_LU] +
>>> +        desc_buf[DEVICE_DESC_PARAM_NUM_WLU];
>>> +
>>>       ufs_fixup_device_setup(hba);
>>>         ufshcd_wb_probe(hba, desc_buf);
>>> @@ -7892,6 +7939,7 @@ static int ufshcd_probe_hba(struct ufs_hba *hba, bool async)
>>>       ufshcd_set_ufs_dev_active(hba);
>>>       ufshcd_force_reset_auto_bkops(hba);
>>>       hba->wlun_dev_clr_ua = true;
>>> +    hba->wlun_rpmb_clr_ua = true;
>>>         /* Gear up to HS gear if supported */
>>>       if (hba->max_pwr_info.is_valid) {
>>> @@ -8475,7 +8523,8 @@ static int ufshcd_set_dev_pwr_mode(struct ufs_hba *hba,
>>>        * handling context.
>>>        */
>>>       hba->host->eh_noresume = 1;
>>> -    ufshcd_clear_ua_wluns(hba);
>>> +    if (hba->wlun_dev_clr_ua)
>>> +        ufshcd_clear_ua_wlun(hba, UFS_UPIU_UFS_DEVICE_WLUN);
>>>         cmd[4] = pwr_mode << 4;
>>>   @@ -8650,23 +8699,7 @@ static void ufshcd_hba_vreg_set_hpm(struct ufs_hba *hba)
>>>           ufshcd_setup_hba_vreg(hba, true);
>>>   }
>>>   -/**
>>> - * ufshcd_suspend - helper function for suspend operations
>>> - * @hba: per adapter instance
>>> - * @pm_op: desired low power operation type
>>> - *
>>> - * This function will try to put the UFS device and link into low power
>>> - * mode based on the "rpm_lvl" (Runtime PM level) or "spm_lvl"
>>> - * (System PM level).
>>> - *
>>> - * If this function is called during shutdown, it will make sure that
>>> - * both UFS device and UFS link is powered off.
>>> - *
>>> - * NOTE: UFS device & link must be active before we enter in this function.
>>> - *
>>> - * Returns 0 for success and non-zero for failure
>>> - */
>>> -static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>> +static int __ufshcd_wl_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>>   {
>>>       int ret = 0;
>>>       int check_for_bkops;
>>> @@ -8674,7 +8707,7 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>>       enum ufs_dev_pwr_mode req_dev_pwr_mode;
>>>       enum uic_link_state req_link_state;
>>>   -    hba->pm_op_in_progress = 1;
>>> +    hba->pm_op_in_progress = true;
>>>       if (!ufshcd_is_shutdown_pm(pm_op)) {
>>>           pm_lvl = ufshcd_is_runtime_pm(pm_op) ?
>>>                hba->rpm_lvl : hba->spm_lvl;
>>> @@ -8697,17 +8730,17 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>>         if (req_dev_pwr_mode == UFS_ACTIVE_PWR_MODE &&
>>>               req_link_state == UIC_LINK_ACTIVE_STATE) {
>>> -        goto disable_clks;
>>> +        goto enable_scaling;
>>>       }
>>>         if ((req_dev_pwr_mode == hba->curr_dev_pwr_mode) &&
>>>           (req_link_state == hba->uic_link_state))
>>> -        goto enable_gating;
>>> +        goto enable_scaling;
>>>         /* UFS device & link must be active before we enter in this function */
>>>       if (!ufshcd_is_ufs_dev_active(hba) || !ufshcd_is_link_active(hba)) {
>>>           ret = -EINVAL;
>>> -        goto enable_gating;
>>> +        goto enable_scaling;
>>>       }
>>>         if (ufshcd_is_runtime_pm(pm_op)) {
>>> @@ -8719,7 +8752,7 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>>                */
>>>               ret = ufshcd_urgent_bkops(hba);
>>>               if (ret)
>>> -                goto enable_gating;
>>> +                goto enable_scaling;
>>>           } else {
>>>               /* make sure that auto bkops is disabled */
>>>               ufshcd_disable_auto_bkops(hba);
>>> @@ -8747,7 +8780,7 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>>           if (!hba->dev_info.b_rpm_dev_flush_capable) {
>>>               ret = ufshcd_set_dev_pwr_mode(hba, req_dev_pwr_mode);
>>>               if (ret)
>>> -                goto enable_gating;
>>> +                goto enable_scaling;
>>>           }
>>>       }
>>>   @@ -8760,7 +8793,6 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>>       if (ret)
>>>           goto set_dev_active;
>>>   -disable_clks:
>>>       /*
>>>        * Call vendor specific suspend callback. As these callbacks may access
>>>        * vendor specific host controller register space call them before the
>>> @@ -8769,28 +8801,9 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>>       ret = ufshcd_vops_suspend(hba, pm_op);
>>>       if (ret)
>>>           goto set_link_active;
>>> -    /*
>>> -     * Disable the host irq as host controller as there won't be any
>>> -     * host controller transaction expected till resume.
>>> -     */
>>> -    ufshcd_disable_irq(hba);
>>> -
>>> -    ufshcd_setup_clocks(hba, false);
>>> -
>>> -    if (ufshcd_is_clkgating_allowed(hba)) {
>>> -        hba->clk_gating.state = CLKS_OFF;
>>> -        trace_ufshcd_clk_gating(dev_name(hba->dev),
>>> -                    hba->clk_gating.state);
>>> -    }
>>> -
>>> -    ufshcd_vreg_set_lpm(hba);
>>> -
>>> -    /* Put the host controller in low power mode if possible */
>>> -    ufshcd_hba_vreg_set_lpm(hba);
>>>       goto out;
>>>     set_link_active:
>>> -    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
>>> @@ -8812,57 +8825,32 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>>       }
>>>       if (!ufshcd_set_dev_pwr_mode(hba, UFS_ACTIVE_PWR_MODE))
>>>           ufshcd_disable_auto_bkops(hba);
>>> -enable_gating:
>>> +enable_scaling:
>>>       if (ufshcd_is_clkscaling_supported(hba))
>>>           ufshcd_clk_scaling_suspend(hba, false);
>>>   -    hba->clk_gating.is_suspended = false;
>>>       hba->dev_info.b_rpm_dev_flush_capable = false;
>>> -    ufshcd_clear_ua_wluns(hba);
>>> -    ufshcd_release(hba);
>>>   out:
>>>       if (hba->dev_info.b_rpm_dev_flush_capable) {
>>>           schedule_delayed_work(&hba->rpm_dev_flush_recheck_work,
>>>               msecs_to_jiffies(RPM_DEV_FLUSH_RECHECK_WORK_DELAY_MS));
>>>       }
>>>   -    hba->pm_op_in_progress = 0;
>>> -
>>> -    if (ret)
>>> -        ufshcd_update_evt_hist(hba, UFS_EVT_SUSPEND_ERR, (u32)ret);
>>> +    if (ret) {
>>> +        ufshcd_update_evt_hist(hba, UFS_EVT_WL_SUSP_ERR, (u32)ret);
>>> +        hba->clk_gating.is_suspended = false;
>>> +        ufshcd_release(hba);
>>> +    }
>>> +    hba->pm_op_in_progress = false;
>>>       return ret;
>>>   }
>>>   -/**
>>> - * ufshcd_resume - helper function for resume operations
>>> - * @hba: per adapter instance
>>> - * @pm_op: runtime PM or system PM
>>> - *
>>> - * This function basically brings the UFS device, UniPro link and controller
>>> - * to active state.
>>> - *
>>> - * Returns 0 for success and non-zero for failure
>>> - */
>>> -static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>> +static int __ufshcd_wl_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>>   {
>>>       int ret;
>>> -    enum uic_link_state old_link_state;
>>> +    enum uic_link_state old_link_state = hba->uic_link_state;
>>>   -    hba->pm_op_in_progress = 1;
>>> -    old_link_state = hba->uic_link_state;
>>> -
>>> -    ufshcd_hba_vreg_set_hpm(hba);
>>> -    ret = ufshcd_vreg_set_hpm(hba);
>>> -    if (ret)
>>> -        goto out;
>>> -
>>> -    /* Make sure clocks are enabled before accessing controller */
>>> -    ret = ufshcd_setup_clocks(hba, true);
>>> -    if (ret)
>>> -        goto disable_vreg;
>>> -
>>> -    /* enable the host irq as host controller would be active soon */
>>> -    ufshcd_enable_irq(hba);
>>> +    hba->pm_op_in_progress = true;
>>>         /*
>>>        * Call vendor specific resume callback. As these callbacks may access
>>> @@ -8871,7 +8859,7 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>>        */
>>>       ret = ufshcd_vops_resume(hba, pm_op);
>>>       if (ret)
>>> -        goto disable_irq_and_vops_clks;
>>> +        goto out;
>>>         /* 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));
>>> @@ -8916,31 +8904,147 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>>            */
>>>           ufshcd_urgent_bkops(hba);
>>>   -    hba->clk_gating.is_suspended = false;
>>> -
>>> -    if (ufshcd_is_clkscaling_supported(hba))
>>> -        ufshcd_clk_scaling_suspend(hba, false);
>>> -
>>> -    /* Enable Auto-Hibernate if configured */
>>> -    ufshcd_auto_hibern8_enable(hba);
>>> +    if (hba->clk_scaling.is_allowed)
>>> +        ufshcd_resume_clkscaling(hba);
>>>         if (hba->dev_info.b_rpm_dev_flush_capable) {
>>>           hba->dev_info.b_rpm_dev_flush_capable = false;
>>>           cancel_delayed_work(&hba->rpm_dev_flush_recheck_work);
>>>       }
>>>   -    ufshcd_clear_ua_wluns(hba);
>>> -
>>> -    /* 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:
>>>       ufshcd_link_state_transition(hba, old_link_state, 0);
>>>   vendor_suspend:
>>>       ufshcd_vops_suspend(hba, pm_op);
>>> -disable_irq_and_vops_clks:
>>> +out:
>>> +    if (ret)
>>> +        ufshcd_update_evt_hist(hba, UFS_EVT_WL_RES_ERR, (u32)ret);
>>> +    hba->clk_gating.is_suspended = false;
>>> +    ufshcd_release(hba);
>>> +    hba->pm_op_in_progress = false;
>>> +    return ret;
>>> +}
>>> +
>>> +static int ufshcd_wl_runtime_suspend(struct device *dev)
>>> +{
>>> +    struct scsi_device *sdev = to_scsi_device(dev);
>>> +    struct ufs_hba *hba;
>>> +    int ret;
>>> +    ktime_t start = ktime_get();
>>> +
>>> +    hba = shost_priv(sdev->host);
>>> +
>>> +    ret = __ufshcd_wl_suspend(hba, UFS_RUNTIME_PM);
>>> +    if (ret)
>>> +        dev_err(&sdev->sdev_gendev, "%s failed: %d\n", __func__, ret);
>>> +
>>> +    trace_ufshcd_wl_runtime_suspend(dev_name(dev), ret,
>>> +        ktime_to_us(ktime_sub(ktime_get(), start)),
>>> +        hba->curr_dev_pwr_mode, hba->uic_link_state);
>>> +
>>> +    return ret;
>>> +}
>>> +
>>> +static int ufshcd_wl_runtime_resume(struct device *dev)
>>> +{
>>> +    struct scsi_device *sdev = to_scsi_device(dev);
>>> +    struct ufs_hba *hba;
>>> +    int ret = 0;
>>> +    ktime_t start = ktime_get();
>>> +
>>> +    hba = shost_priv(sdev->host);
>>> +
>>> +    ret = __ufshcd_wl_resume(hba, UFS_RUNTIME_PM);
>>> +    if (ret)
>>> +        dev_err(&sdev->sdev_gendev, "%s failed: %d\n", __func__, ret);
>>> +
>>> +    trace_ufshcd_wl_runtime_resume(dev_name(dev), ret,
>>> +        ktime_to_us(ktime_sub(ktime_get(), start)),
>>> +        hba->curr_dev_pwr_mode, hba->uic_link_state);
>>> +
>>> +    return ret;
>>> +}
>>> +
>>> +#ifdef CONFIG_PM_SLEEP
>>> +static int ufshcd_wl_suspend(struct device *dev)
>>> +{
>>> +    struct scsi_device *sdev = to_scsi_device(dev);
>>> +    struct ufs_hba *hba;
>>> +    int ret;
>>> +    ktime_t start = ktime_get();
>>> +
>>> +    hba = shost_priv(sdev->host);
>>> +    ret = __ufshcd_wl_suspend(hba, UFS_SYSTEM_PM);
>>> +    if (ret)
>>> +        dev_err(&sdev->sdev_gendev, "%s failed: %d\n", __func__,  ret);
>>> +
>>> +    trace_ufshcd_wl_suspend(dev_name(dev), ret,
>>> +        ktime_to_us(ktime_sub(ktime_get(), start)),
>>> +        hba->curr_dev_pwr_mode, hba->uic_link_state);
>>> +
>>> +    return ret;
>>> +}
>>> +
>>> +static int ufshcd_wl_resume(struct device *dev)
>>> +{
>>> +    struct scsi_device *sdev = to_scsi_device(dev);
>>> +    struct ufs_hba *hba;
>>> +    int ret = 0;
>>> +    ktime_t start = ktime_get();
>>> +
>>> +    if (pm_runtime_suspended(dev))
>>> +        return 0;
>>> +    hba = shost_priv(sdev->host);
>>> +
>>> +    ret = __ufshcd_wl_resume(hba, UFS_SYSTEM_PM);
>>> +    if (ret)
>>> +        dev_err(&sdev->sdev_gendev, "%s failed: %d\n", __func__, ret);
>>> +
>>> +    trace_ufshcd_wl_resume(dev_name(dev), ret,
>>> +        ktime_to_us(ktime_sub(ktime_get(), start)),
>>> +        hba->curr_dev_pwr_mode, hba->uic_link_state);
>>> +
>>> +    return ret;
>>> +}
>>> +#endif
>>> +
>>> +static void ufshcd_wl_shutdown(struct device *dev)
>>> +{
>>> +    struct scsi_device *sdev = to_scsi_device(dev);
>>> +    struct ufs_hba *hba;
>>> +
>>> +    hba = shost_priv(sdev->host);
>>> +    /* Turn on everything while shutting down */
>>> +    scsi_autopm_get_device(sdev);
>>> +    scsi_device_quiesce(sdev);
>>> +    shost_for_each_device(sdev, hba->host) {
>>> +        if (sdev == hba->sdev_ufs_device)
>>> +            continue;
>>> +        scsi_device_quiesce(sdev);
>>> +    }
>>> +    __ufshcd_wl_suspend(hba, UFS_SHUTDOWN_PM);
>>> +}
>>> +
>>> +/**
>>> + * ufshcd_suspend - helper function for suspend operations
>>> + * @hba: per adapter instance
>>> + *
>>> + * This function will put disable irqs, turn off clocks
>>> + * and set vreg and hba-vreg in lpm mode.
>>> + * Also check the description of __ufshcd_wl_suspend().
>>> + */
>>> +static void ufshcd_suspend(struct ufs_hba *hba)
>>> +{
>>> +    hba->pm_op_in_progress = 1;
>>> +
>>> +    /*
>>> +     * Disable the host irq as host controller as there won't be any
>>> +     * host controller transaction expected till resume.
>>> +     */
>>>       ufshcd_disable_irq(hba);
>>>       ufshcd_setup_clocks(hba, false);
>>>       if (ufshcd_is_clkgating_allowed(hba)) {
>>> @@ -8948,6 +9052,43 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>>           trace_ufshcd_clk_gating(dev_name(hba->dev),
>>>                       hba->clk_gating.state);
>>>       }
>>> +
>>> +    ufshcd_vreg_set_lpm(hba);
>>> +    /* Put the host controller in low power mode if possible */
>>> +    ufshcd_hba_vreg_set_lpm(hba);
>>> +    hba->pm_op_in_progress = 0;
>>> +}
>>> +
>>> +/**
>>> + * ufshcd_resume - helper function for resume operations
>>> + * @hba: per adapter instance
>>> + *
>>> + * This function basically turns on the regulators, clocks and
>>> + * irqs of the hba.
>>> + * Also check the description of __ufshcd_wl_resume().
>>> + *
>>> + * Returns 0 for success and non-zero for failure
>>> + */
>>> +static int ufshcd_resume(struct ufs_hba *hba)
>>> +{
>>> +    int ret;
>>> +
>>> +    hba->pm_op_in_progress = 1;
>>> +
>>> +    ufshcd_hba_vreg_set_hpm(hba);
>>> +    ret = ufshcd_vreg_set_hpm(hba);
>>> +    if (ret)
>>> +        goto out;
>>> +
>>> +    /* Make sure clocks are enabled before accessing controller */
>>> +    ret = ufshcd_setup_clocks(hba, true);
>>> +    if (ret)
>>> +        goto disable_vreg;
>>> +
>>> +    /* enable the host irq as host controller would be active soon */
>>> +    ufshcd_enable_irq(hba);
>>> +    goto out;
>>> +
>>>   disable_vreg:
>>>       ufshcd_vreg_set_lpm(hba);
>>>   out:
>>> @@ -8962,6 +9103,7 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>>    * @hba: per adapter instance
>>>    *
>>>    * Check the description of ufshcd_suspend() function for more details.
>>> + * Also check the description of __ufshcd_wl_suspend().
>>>    *
>>>    * Returns 0 for success and non-zero for failure
>>>    */
>>> @@ -8987,21 +9129,7 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
>>>            !hba->dev_info.b_rpm_dev_flush_capable)
>>>           goto out;
>>>   -    if (pm_runtime_suspended(hba->dev)) {
>>> -        /*
>>> -         * UFS device and/or UFS link low power states during runtime
>>> -         * suspend seems to be different than what is expected during
>>> -         * system suspend. Hence runtime resume the devic & link and
>>> -         * let the system suspend low power states to take effect.
>>> -         * TODO: If resume takes longer time, we might have optimize
>>> -         * it in future by not resuming everything if possible.
>>> -         */
>>> -        ret = ufshcd_runtime_resume(hba);
>>> -        if (ret)
>>> -            goto out;
>>> -    }
>>> -
>>> -    ret = ufshcd_suspend(hba, UFS_SYSTEM_PM);
>>> +    ufshcd_suspend(hba);
>>>   out:
>>>       trace_ufshcd_system_suspend(dev_name(hba->dev), ret,
>>>           ktime_to_us(ktime_sub(ktime_get(), start)),
>>> @@ -9023,7 +9151,6 @@ EXPORT_SYMBOL(ufshcd_system_suspend);
>>>     int ufshcd_system_resume(struct ufs_hba *hba)
>>>   {
>>> -    int ret = 0;
>>>       ktime_t start = ktime_get();
>>>         if (!hba)
>>> @@ -9034,22 +9161,18 @@ int ufshcd_system_resume(struct ufs_hba *hba)
>>>           down(&hba->host_sem);
>>>       }
>>>   -    if (!hba->is_powered || pm_runtime_suspended(hba->dev))
>>> -        /*
>>> -         * Let the runtime resume take care of resuming
>>> -         * if runtime suspended.
>>> -         */
>>> +    if (!hba->is_powered)
>>>           goto out;
>>>       else
>>> -        ret = ufshcd_resume(hba, UFS_SYSTEM_PM);
>>> +        ufshcd_resume(hba);
>>>   out:
>>> -    trace_ufshcd_system_resume(dev_name(hba->dev), ret,
>>> +    trace_ufshcd_system_resume(dev_name(hba->dev), 0,
>>>           ktime_to_us(ktime_sub(ktime_get(), start)),
>>>           hba->curr_dev_pwr_mode, hba->uic_link_state);
>>> -    if (!ret)
>>> -        hba->is_sys_suspended = false;
>>> +
>>> +    hba->is_sys_suspended = false;
>>>       up(&hba->host_sem);
>>> -    return ret;
>>> +    return 0;
>>>   }
>>>   EXPORT_SYMBOL(ufshcd_system_resume);
>>>   @@ -9058,12 +9181,12 @@ EXPORT_SYMBOL(ufshcd_system_resume);
>>>    * @hba: per adapter instance
>>>    *
>>>    * Check the description of ufshcd_suspend() function for more details.
>>> + * Also check the description of __ufshcd_wl_suspend().
>>>    *
>>>    * Returns 0 for success and non-zero for failure
>>>    */
>>>   int ufshcd_runtime_suspend(struct ufs_hba *hba)
>>>   {
>>> -    int ret = 0;
>>>       ktime_t start = ktime_get();
>>>         if (!hba)
>>> @@ -9072,12 +9195,12 @@ int ufshcd_runtime_suspend(struct ufs_hba *hba)
>>>       if (!hba->is_powered)
>>>           goto out;
>>>       else
>>> -        ret = ufshcd_suspend(hba, UFS_RUNTIME_PM);
>>> +        ufshcd_suspend(hba);
>>>   out:
>>> -    trace_ufshcd_runtime_suspend(dev_name(hba->dev), ret,
>>> +    trace_ufshcd_runtime_suspend(dev_name(hba->dev), 0,
>>>           ktime_to_us(ktime_sub(ktime_get(), start)),
>>>           hba->curr_dev_pwr_mode, hba->uic_link_state);
>>> -    return ret;
>>> +    return 0;
>>>   }
>>>   EXPORT_SYMBOL(ufshcd_runtime_suspend);
>>>   @@ -9085,26 +9208,14 @@ EXPORT_SYMBOL(ufshcd_runtime_suspend);
>>>    * ufshcd_runtime_resume - runtime resume routine
>>>    * @hba: per adapter instance
>>>    *
>>> - * This function basically brings the UFS device, UniPro link and controller
>>> + * This function basically brings controller
>>>    * to active state. Following operations are done in this function:
>>>    *
>>>    * 1. Turn on all the controller related clocks
>>> - * 2. Bring the UniPro link out of Hibernate state
>>> - * 3. If UFS device is in sleep state, turn ON VCC rail and bring the UFS device
>>> - *    to active state.
>>> - * 4. If auto-bkops is enabled on the device, disable it.
>>> - *
>>> - * So following would be the possible power state after this function return
>>> - * successfully:
>>> - *    S1: UFS device in Active state with VCC rail ON
>>> - *        UniPro link in Active state
>>> - *        All the UFS/UniPro controller clocks are ON
>>> - *
>>> - * Returns 0 for success and non-zero for failure
>>> + * 2. Turn ON VCC rail
>>>    */
>>>   int ufshcd_runtime_resume(struct ufs_hba *hba)
>>>   {
>>> -    int ret = 0;
>>>       ktime_t start = ktime_get();
>>>         if (!hba)
>>> @@ -9113,12 +9224,12 @@ int ufshcd_runtime_resume(struct ufs_hba *hba)
>>>       if (!hba->is_powered)
>>>           goto out;
>>>       else
>>> -        ret = ufshcd_resume(hba, UFS_RUNTIME_PM);
>>> +        ufshcd_resume(hba);
>>>   out:
>>> -    trace_ufshcd_runtime_resume(dev_name(hba->dev), ret,
>>> +    trace_ufshcd_runtime_resume(dev_name(hba->dev), 0,
>>>           ktime_to_us(ktime_sub(ktime_get(), start)),
>>>           hba->curr_dev_pwr_mode, hba->uic_link_state);
>>> -    return ret;
>>> +    return 0;
>>>   }
>>>   EXPORT_SYMBOL(ufshcd_runtime_resume);
>>>   @@ -9132,14 +9243,13 @@ EXPORT_SYMBOL(ufshcd_runtime_idle);
>>>    * ufshcd_shutdown - shutdown routine
>>>    * @hba: per adapter instance
>>>    *
>>> - * This function would power off both UFS device and UFS link.
>>> + * This function would turn off both UFS device and UFS hba
>>> + * regulators. It would also disable clocks.
>>>    *
>>>    * Returns 0 always to allow force shutdown even in case of errors.
>>>    */
>>>   int ufshcd_shutdown(struct ufs_hba *hba)
>>>   {
>>> -    int ret = 0;
>>> -
>>>       down(&hba->host_sem);
>>>       hba->shutting_down = true;
>>>       up(&hba->host_sem);
>>> @@ -9152,10 +9262,8 @@ int ufshcd_shutdown(struct ufs_hba *hba)
>>>         pm_runtime_get_sync(hba->dev);
>>>   -    ret = ufshcd_suspend(hba, UFS_SHUTDOWN_PM);
>>> +    ufshcd_suspend(hba);
>>>   out:
>>> -    if (ret)
>>> -        dev_err(hba->dev, "%s failed, err %d\n", __func__, ret);
>>>       hba->is_powered = false;
>>>       /* allow force shutdown even in case of errors */
>>>       return 0;
>>> @@ -9477,15 +9585,163 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
>>>   }
>>>   EXPORT_SYMBOL_GPL(ufshcd_init);
>>>   +void ufshcd_resume_complete(struct device *dev)
>>> +{
>>> +    struct ufs_hba *hba = dev_get_drvdata(dev);
>>> +
>>> +    pm_runtime_put_noidle(&hba->sdev_ufs_device->sdev_gendev);
>>> +}
>>> +EXPORT_SYMBOL_GPL(ufshcd_resume_complete);
>>> +
>>> +int ufshcd_suspend_prepare(struct device *dev)
>>> +{
>>> +    struct ufs_hba *hba = dev_get_drvdata(dev);
>>> +
>>> +    /*
>>> +     * SCSI assumes that runtime-pm and system-pm for scsi drivers
>>> +     * are same. And it doesn't wake up the device for system-suspend
>>> +     * if it's runtime suspended. But ufs doesn't follow that.
>>> +     * The rpm-lvl and spm-lvl can be different in ufs.
>>> +     * Force it to honor system-suspend.
>>> +     */
>>> +    scsi_autopm_get_device(hba->sdev_ufs_device);
>>> +    /* Refer ufshcd_resume_complete() */
>>> +    pm_runtime_get_noresume(&hba->sdev_ufs_device->sdev_gendev);
>>> +    scsi_autopm_put_device(hba->sdev_ufs_device);
>>> +    return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(ufshcd_suspend_prepare);
>>> +
>>> +#ifdef CONFIG_PM_SLEEP
>>> +static int ufshcd_wl_poweroff(struct device *dev)
>>> +{
>>> +    ufshcd_wl_shutdown(dev);
>>> +    return 0;
>>> +}
>>> +#endif
>>> +
>>> +static int ufshcd_wl_probe(struct device *dev)
>>> +{
>>> +    return is_device_wlun(to_scsi_device(dev)) ? 0 : -ENODEV;
>>
>> The "ufs_device_wlun" driver owns PM for sdev_ufs_device because it
>> provides the dev_pm_ops.  This is where the pm_runtime_allow() belongs
>> and it is symmetrical with the pm_runtime_forbid() in ufshcd_wl_remove().
>>
>>     if (!is_device_wlun(to_scsi_device(dev)))
>>         return -ENODEV;
>>     blk_pm_runtime_init(dev);
>>     pm_runtime_set_autosuspend_delay(dev, 0);
>>     pm_runtime_allow(dev);
>>
>> Note sdev_ufs_device will not runtime suspend here unless the
>> device links have been added and all consumers have suspended.
>> That is handled separately by the pm_runtime_get_noresume() in
>> ufshcd_slave_configure() and the pm_runtime_put() when luns_avail == 1
>> in ufshcd_setup_links().
>>
>>> +}
>>> +
>>> +static int ufshcd_wl_remove(struct device *dev)
>>> +{
>>> +    pm_runtime_forbid(dev);
>>> +    return 0;
>>> +}
>>> +
>>> +static const struct dev_pm_ops ufshcd_wl_pm_ops = {
>>> +#ifdef CONFIG_PM_SLEEP
>>> +    .suspend = ufshcd_wl_suspend,
>>> +    .resume = ufshcd_wl_resume,
>>> +    .freeze = ufshcd_wl_suspend,
>>> +    .thaw = ufshcd_wl_resume,
>>> +    .poweroff = ufshcd_wl_poweroff,
>>> +    .restore = ufshcd_wl_resume,
>>> +#endif
>>> +    SET_RUNTIME_PM_OPS(ufshcd_wl_runtime_suspend, ufshcd_wl_runtime_resume, NULL)
>>> +};
>>> +
>>> +/**
>>> + * ufs_dev_wlun_template - describes ufs device wlun
>>> + * ufs-device wlun - used to send pm commands
>>> + * All luns are consumers of ufs-device wlun.
>>> + *
>>> + * Currently, no sd driver is present for wluns.
>>> + * Hence the no specific pm operations are performed.
>>> + * With ufs design, SSU should be sent to ufs-device wlun.
>>> + * Hence register a scsi driver for ufs wluns only.
>>> + */
>>> +static struct scsi_driver ufs_dev_wlun_template = {
>>> +    .gendrv = {
>>> +        .name = "ufs_device_wlun",
>>> +        .owner = THIS_MODULE,
>>> +        .probe = ufshcd_wl_probe,
>>> +        .remove = ufshcd_wl_remove,
>>> +        .pm = &ufshcd_wl_pm_ops,
>>> +        .shutdown = ufshcd_wl_shutdown,
>>> +    },
>>> +};
>>> +
>>> +static int ufshcd_rpmb_probe(struct device *dev)
>>> +{
>>> +    return is_rpmb_wlun(to_scsi_device(dev)) ? 0 : -ENODEV;
>>> +}
>>> +
>>> +static inline int ufshcd_clear_rpmb_uac(struct ufs_hba *hba)
>>> +{
>>> +    int ret = 0;
>>> +
>>> +    if (!hba->wlun_rpmb_clr_ua)
>>> +        return 0;
>>> +    ret = ufshcd_clear_ua_wlun(hba, UFS_UPIU_RPMB_WLUN);
>>> +    if (!ret)
>>> +        hba->wlun_rpmb_clr_ua = 0;
>>> +    return ret;
>>> +}
>>> +
>>> +static int ufshcd_rpmb_runtime_resume(struct device *dev)
>>> +{
>>> +    struct ufs_hba *hba = wlun_dev_to_hba(dev);
>>> +
>>> +    if (hba->sdev_rpmb)
>>> +        return ufshcd_clear_rpmb_uac(hba);
>>> +    return 0;
>>> +}
>>> +
>>> +static int ufshcd_rpmb_resume(struct device *dev)
>>> +{
>>> +    struct ufs_hba *hba = wlun_dev_to_hba(dev);
>>> +
>>> +    if (hba->sdev_rpmb && !pm_runtime_suspended(dev))
>>> +        return ufshcd_clear_rpmb_uac(hba);
>>> +    return 0;
>>> +}
>>> +
>>> +static const struct dev_pm_ops ufs_rpmb_pm_ops = {
>>> +    SET_RUNTIME_PM_OPS(NULL, ufshcd_rpmb_runtime_resume, NULL)
>>> +    SET_SYSTEM_SLEEP_PM_OPS(NULL, ufshcd_rpmb_resume)
>>> +};
>>> +
>>> +/**
>>> + * Describes the ufs rpmb wlun.
>>> + * Used only to send uac.
>>> + */
>>> +static struct scsi_driver ufs_rpmb_wlun_template = {
>>> +    .gendrv = {
>>> +        .name = "ufs_rpmb_wlun",
>>> +        .owner = THIS_MODULE,
>>> +        .probe = ufshcd_rpmb_probe,
>>> +        .pm = &ufs_rpmb_pm_ops,
>>> +    },
>>> +};
>>> +
>>>   static int __init ufshcd_core_init(void)
>>>   {
>>> +    int ret;
>>> +
>>>       ufs_debugfs_init();
>>> +
>>> +    ret = scsi_register_driver(&ufs_dev_wlun_template.gendrv);
>>> +    if (ret) {
>>> +        ufs_debugfs_exit();
>>> +        return ret;
>>> +    }
>>> +    ret = scsi_register_driver(&ufs_rpmb_wlun_template.gendrv);
>>> +    if (ret) {
>>> +        ufs_debugfs_exit();
>>> +        scsi_unregister_driver(&ufs_dev_wlun_template.gendrv);
>>> +        return ret;
>>> +    }
>>>       return 0;
>>>   }
>>>     static void __exit ufshcd_core_exit(void)
>>>   {
>>>       ufs_debugfs_exit();
>>> +    scsi_unregister_driver(&ufs_dev_wlun_template.gendrv);
>>> +    scsi_unregister_driver(&ufs_rpmb_wlun_template.gendrv);
>>>   }
>>>     module_init(ufshcd_core_init);
>>> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
>>> index ee61f82..7841b2a 100644
>>> --- a/drivers/scsi/ufs/ufshcd.h
>>> +++ b/drivers/scsi/ufs/ufshcd.h
>>> @@ -72,6 +72,8 @@ enum ufs_event_type {
>>>       UFS_EVT_LINK_STARTUP_FAIL,
>>>       UFS_EVT_RESUME_ERR,
>>>       UFS_EVT_SUSPEND_ERR,
>>> +    UFS_EVT_WL_SUSP_ERR,
>>> +    UFS_EVT_WL_RES_ERR,
>>>         /* abnormal events */
>>>       UFS_EVT_DEV_RESET,
>>> @@ -804,6 +806,7 @@ struct ufs_hba {
>>>       struct list_head clk_list_head;
>>>         bool wlun_dev_clr_ua;
>>> +    bool wlun_rpmb_clr_ua;
>>>         /* Number of requests aborts */
>>>       int req_abort_count;
>>> @@ -841,6 +844,7 @@ struct ufs_hba {
>>>   #ifdef CONFIG_DEBUG_FS
>>>       struct dentry *debugfs_root;
>>>   #endif
>>> +    u32 luns_avail;
>>>   };
>>>     /* Returns true if clocks can be gated. Otherwise false */
>>> @@ -1100,6 +1104,8 @@ int ufshcd_exec_raw_upiu_cmd(struct ufs_hba *hba,
>>>                    enum query_opcode desc_op);
>>>     int ufshcd_wb_ctrl(struct ufs_hba *hba, bool enable);
>>> +int ufshcd_suspend_prepare(struct device *dev);
>>> +void ufshcd_resume_complete(struct device *dev);
>>>     /* Wrapper functions for safely calling variant operations */
>>>   static inline const char *ufshcd_get_var_name(struct ufs_hba *hba)
>>> diff --git a/include/trace/events/ufs.h b/include/trace/events/ufs.h
>>> index e151477..d9d233b 100644
>>> --- a/include/trace/events/ufs.h
>>> +++ b/include/trace/events/ufs.h
>>> @@ -246,6 +246,26 @@ DEFINE_EVENT(ufshcd_template, ufshcd_init,
>>>                 int dev_state, int link_state),
>>>            TP_ARGS(dev_name, err, usecs, dev_state, link_state));
>>>   +DEFINE_EVENT(ufshcd_template, ufshcd_wl_suspend,
>>> +         TP_PROTO(const char *dev_name, int err, s64 usecs,
>>> +              int dev_state, int link_state),
>>> +         TP_ARGS(dev_name, err, usecs, dev_state, link_state));
>>> +
>>> +DEFINE_EVENT(ufshcd_template, ufshcd_wl_resume,
>>> +         TP_PROTO(const char *dev_name, int err, s64 usecs,
>>> +              int dev_state, int link_state),
>>> +         TP_ARGS(dev_name, err, usecs, dev_state, link_state));
>>> +
>>> +DEFINE_EVENT(ufshcd_template, ufshcd_wl_runtime_suspend,
>>> +         TP_PROTO(const char *dev_name, int err, s64 usecs,
>>> +              int dev_state, int link_state),
>>> +         TP_ARGS(dev_name, err, usecs, dev_state, link_state));
>>> +
>>> +DEFINE_EVENT(ufshcd_template, ufshcd_wl_runtime_resume,
>>> +         TP_PROTO(const char *dev_name, int err, s64 usecs,
>>> +              int dev_state, int link_state),
>>> +         TP_ARGS(dev_name, err, usecs, dev_state, link_state));
>>> +
>>>   TRACE_EVENT(ufshcd_command,
>>>       TP_PROTO(const char *dev_name, enum ufs_trace_str_t str_t,
>>>            unsigned int tag, u32 doorbell, int transfer_len, u32 intr,
>>>
>>
>
>