[v8,1/2] scsi: ufs: Enable power management for wlun

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>
---
 drivers/scsi/ufs/cdns-pltfrm.c     |   2 +
 drivers/scsi/ufs/tc-dwc-g210-pci.c |   2 +
 drivers/scsi/ufs/ufs-exynos.c      |   2 +
 drivers/scsi/ufs/ufs-hisi.c        |   2 +
 drivers/scsi/ufs/ufs-mediatek.c    |   2 +
 drivers/scsi/ufs/ufs-qcom.c        |   2 +
 drivers/scsi/ufs/ufshcd-pci.c      |  26 +-
 drivers/scsi/ufs/ufshcd.c          | 540 ++++++++++++++++++++++++++++++-------
 drivers/scsi/ufs/ufshcd.h          |   7 +
 include/trace/events/ufs.h         |  20 ++
 10 files changed, 483 insertions(+), 122 deletions(-)

Hi

A couple of minor things, but also a potential issue with when link state
transitions are done.  Please see comments below.

On 26/02/21 1:37 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>
> ---
>  drivers/scsi/ufs/cdns-pltfrm.c     |   2 +
>  drivers/scsi/ufs/tc-dwc-g210-pci.c |   2 +
>  drivers/scsi/ufs/ufs-exynos.c      |   2 +
>  drivers/scsi/ufs/ufs-hisi.c        |   2 +
>  drivers/scsi/ufs/ufs-mediatek.c    |   2 +
>  drivers/scsi/ufs/ufs-qcom.c        |   2 +
>  drivers/scsi/ufs/ufshcd-pci.c      |  26 +-
>  drivers/scsi/ufs/ufshcd.c          | 540 ++++++++++++++++++++++++++++++-------
>  drivers/scsi/ufs/ufshcd.h          |   7 +
>  include/trace/events/ufs.h         |  20 ++
>  10 files changed, 483 insertions(+), 122 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-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..df1eabb 100644
> --- a/drivers/scsi/ufs/ufs-mediatek.c
> +++ b/drivers/scsi/ufs/ufs-mediatek.c
> @@ -1097,6 +1097,8 @@ 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/ufshcd-pci.c b/drivers/scsi/ufs/ufshcd-pci.c
> index fadd566..fef1ee4 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
> @@ -370,8 +347,9 @@ static const struct dev_pm_ops ufshcd_pci_pm_ops = {
>  	.resume		= ufshcd_pci_resume,
>  	.freeze		= ufshcd_pci_suspend,
>  	.thaw		= ufshcd_pci_resume,
> -	.poweroff	= ufshcd_pci_poweroff,
>  	.restore	= ufshcd_pci_resume,

Can use SET_SYSTEM_SLEEP_PM_OPS(ufshcd_pci_suspend, ufshcd_pci_resume) for
the ones above.

> +	.prepare	 = ufshcd_suspend_prepare,
> +	.complete	= ufshcd_resume_complete,
>  #endif
>  	SET_RUNTIME_PM_OPS(ufshcd_pci_runtime_suspend,
>  			   ufshcd_pci_runtime_resume,
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 45624c7..0e8e76a 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;
> @@ -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);
> +		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)
> +			return;
> +
> +		pm_runtime_put_noidle(&hba->sdev_ufs_device->sdev_gendev);
> +		pm_runtime_mark_last_busy(&hba->sdev_ufs_device->sdev_gendev);
> +	} 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;
>  }
>  
> @@ -4985,15 +5036,9 @@ 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 +5634,8 @@ 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 +5652,6 @@ 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 +5667,6 @@ 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;
>  }
>  
> @@ -7210,8 +7246,7 @@ static inline void ufshcd_blk_pm_runtime_init(struct scsi_device *sdev)
>  	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, 0);
>  	scsi_autopm_put_device(sdev);
>  }
>  
> @@ -7254,6 +7289,15 @@ static int ufshcd_scsi_add_wlus(struct ufs_hba *hba)
>  		goto out;
>  	}
>  	ufshcd_blk_pm_runtime_init(hba->sdev_ufs_device);
> +	/*
> +	 * A pm_runtime_put_sync is invoked when this device enables blk_pm_runtime
> +	 * & would suspend the device-wlun upon timer expiry.
> +	 * But suspending device wlun _may_ put the ufs device in the pre-defined
> +	 * low power mode (SSU <rpm_lvl>). Probing of other luns may fail then.
> +	 * Don't allow this suspend until all the luns have been probed.
> +	 * See pm_runtime_mark_last_busy in ufshcd_setup_links.
> +	 */
> +	pm_runtime_get_noresume(&hba->sdev_ufs_device->sdev_gendev);
>  	scsi_device_put(hba->sdev_ufs_device);
>  
>  	hba->sdev_rpmb = __scsi_add_device(hba->host, 0, 0,
> @@ -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) {
> @@ -7964,6 +8012,7 @@ static void ufshcd_async_scan(void *data, async_cookie_t cookie)
>  		pm_runtime_put_sync(hba->dev);
>  		ufshcd_hba_exit(hba);
>  	}
> +	hba->init_done = true;
>  }
>  
>  static const struct attribute_group *ufshcd_driver_groups[] = {
> @@ -8475,7 +8524,8 @@ 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;
>  
> @@ -8650,31 +8700,20 @@ 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;
>  	enum ufs_pm_level pm_lvl;
>  	enum ufs_dev_pwr_mode req_dev_pwr_mode;
>  	enum uic_link_state req_link_state;
>  
> -	hba->pm_op_in_progress = 1;
> +	/*
> +	 * Is invoked when the device wlun is added to sysfs
> +	 * But by then hba->sdev_ufs_device may not be initialized.
> +	 */
> +	if (!hba->init_done)
> +		return 0;
> +	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;
> @@ -8690,24 +8729,23 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>  	 * just gate the clocks.
>  	 */
>  	ufshcd_hold(hba, false);
> -	hba->clk_gating.is_suspended = true;
>  
>  	if (ufshcd_is_clkscaling_supported(hba))
>  		ufshcd_clk_scaling_suspend(hba, true);
>  
>  	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 +8757,7 @@ 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);
> @@ -8746,10 +8784,213 @@ 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;
> +			if (!ret)
> +				goto out;
>  		}
>  	}
> +enable_scaling:
> +	if (ufshcd_is_clkscaling_supported(hba))
> +		ufshcd_clk_scaling_suspend(hba, false);
> +
> +	hba->dev_info.b_rpm_dev_flush_capable = false;
> +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));
> +	}
> +	if (ret)
> +		ufshcd_update_evt_hist(hba, UFS_EVT_WL_SUSP_ERR, (u32)ret);
> +	ufshcd_release(hba);
> +	hba->pm_op_in_progress = false;
> +	return ret;
> +}
> +
> +static int __ufshcd_wl_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
> +{
> +	int ret = 0;
> +
> +	if (!hba->init_done)
> +		return 0;
> +
> +	hba->pm_op_in_progress = true;
> +	ufshcd_hold(hba, false);
> +	if (ufshcd_is_ufs_dev_deepsleep(hba)) {
> +		/* The device is in DeepSleep but hba was not suspended */
> +		ret = ufshcd_reset_and_restore(hba);
> +		if (ret)
> +			goto out;
> +	}
> +
> +	if (!ufshcd_is_ufs_dev_active(hba)) {
> +		ret = ufshcd_set_dev_pwr_mode(hba, UFS_ACTIVE_PWR_MODE);
> +		if (ret)
> +			goto out;
> +	}
> +
> +	if (ufshcd_keep_autobkops_enabled_except_suspend(hba))
> +		ufshcd_enable_auto_bkops(hba);
> +	else
> +		/*
> +		 * If BKOPs operations are urgently needed at this moment then
> +		 * keep auto-bkops enabled or else disable it.
> +		 */
> +		ufshcd_urgent_bkops(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);
> +	}
> +
> +out:
> +	if (ret)
> +		ufshcd_update_evt_hist(hba, UFS_EVT_WL_RES_ERR, (u32)ret);
> +	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
> + * @pm_op: desired low power operation type
> + *
> + * This function will try to put the UFS 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
> + * link is powered off.
> + *
> + * Returns 0 for success and non-zero for failure
> + */
> +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;
> +
> +	hba->pm_op_in_progress = 1;
> +	if (!ufshcd_is_shutdown_pm(pm_op)) {
> +		pm_lvl = ufshcd_is_runtime_pm(pm_op) ?
> +			 hba->rpm_lvl : hba->spm_lvl;
> +		req_dev_pwr_mode = ufs_get_pm_lvl_to_dev_pwr_mode(pm_lvl);
> +		req_link_state = ufs_get_pm_lvl_to_link_pwr_state(pm_lvl);
> +	} else {
> +		req_dev_pwr_mode = UFS_POWERDOWN_PWR_MODE;
> +		req_link_state = UIC_LINK_OFF_STATE;
> +	}
> +
> +	/*
> +	 * If we can't transition into any of the low power modes
> +	 * just gate the clocks.
> +	 */
> +	ufshcd_hold(hba, false);
> +	hba->clk_gating.is_suspended = true;
>  
>  	/*
>  	 * In the case of DeepSleep, the device is expected to remain powered
> @@ -8758,9 +8999,8 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>  	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;
> +		goto enable_gating;
>  
> -disable_clks:
>  	/*
>  	 * Call vendor specific suspend callback. As these callbacks may access
>  	 * vendor specific host controller register space call them before the
> @@ -8790,7 +9030,6 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>  	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
> @@ -8804,28 +9043,15 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>  		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_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:
> -	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)
> @@ -8846,10 +9072,8 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>  static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>  {
>  	int ret;
> -	enum uic_link_state old_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);
> @@ -8901,43 +9125,14 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>  			goto vendor_suspend;
>  	}

The ufshcd_reset_and_restore() in ufshcd_resume() will also change the power
mode of the UFS device to active.  Until the UFS device is also resumed and
then suspended, it will not return to a low power mode.

It looks like the link state transations should also be moved to
__ufshcd_wl_suspend / resume ?

>  
> -	if (!ufshcd_is_ufs_dev_active(hba)) {
> -		ret = ufshcd_set_dev_pwr_mode(hba, UFS_ACTIVE_PWR_MODE);
> -		if (ret)
> -			goto set_old_link_state;
> -	}
> -
> -	if (ufshcd_keep_autobkops_enabled_except_suspend(hba))
> -		ufshcd_enable_auto_bkops(hba);
> -	else
> -		/*
> -		 * If BKOPs operations are urgently needed at this moment then
> -		 * keep auto-bkops enabled or else disable it.
> -		 */
> -		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->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);
>  
>  	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:
> @@ -9477,15 +9672,164 @@ 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;
> +}
> +
> +static int ufshcd_wl_remove(struct device *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) {
> +		pr_err("Register device wlun driver failed: %d\n",
> +			ret);

The driver_register has some error messages, so I am not sure we need this
message.

> +		return ret;
> +	}
> +
> +	ret = scsi_register_driver(&ufs_rpmb_wlun_template.gendrv);
> +	if (ret) {
> +		pr_err("Register rpmb wlun driver failed: %d\n",
> +			ret);

Ditto the message, but also need to unregister &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..e246ec3 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 +844,8 @@ struct ufs_hba {
>  #ifdef CONFIG_DEBUG_FS
>  	struct dentry *debugfs_root;
>  #endif
> +	bool init_done;
> +	u32 luns_avail;
>  };
>  
>  /* Returns true if clocks can be gated. Otherwise false */
> @@ -1100,6 +1105,8 @@ 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,
>

On Mon, Mar 01 2021 at 05:23 -0800, Adrian Hunter wrote:
>Hi
>
>A couple of minor things, but also a potential issue with when link state
>transitions are done.  Please see comments below.
>
>On 26/02/21 1:37 am, Asutosh Das wrote:

Hi Adrian
Thanks for your comments.

>> 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>
>> ---
>>  drivers/scsi/ufs/cdns-pltfrm.c     |   2 +
>>  drivers/scsi/ufs/tc-dwc-g210-pci.c |   2 +
>>  drivers/scsi/ufs/ufs-exynos.c      |   2 +
>>  drivers/scsi/ufs/ufs-hisi.c        |   2 +
>>  drivers/scsi/ufs/ufs-mediatek.c    |   2 +
>>  drivers/scsi/ufs/ufs-qcom.c        |   2 +
>>  drivers/scsi/ufs/ufshcd-pci.c      |  26 +-
>>  drivers/scsi/ufs/ufshcd.c          | 540 ++++++++++++++++++++++++++++++-------
>>  drivers/scsi/ufs/ufshcd.h          |   7 +
>>  include/trace/events/ufs.h         |  20 ++
>>  10 files changed, 483 insertions(+), 122 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-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..df1eabb 100644
>> --- a/drivers/scsi/ufs/ufs-mediatek.c
>> +++ b/drivers/scsi/ufs/ufs-mediatek.c
>> @@ -1097,6 +1097,8 @@ 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/ufshcd-pci.c b/drivers/scsi/ufs/ufshcd-pci.c
>> index fadd566..fef1ee4 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
>> @@ -370,8 +347,9 @@ static const struct dev_pm_ops ufshcd_pci_pm_ops = {
>>  	.resume		= ufshcd_pci_resume,
>>  	.freeze		= ufshcd_pci_suspend,
>>  	.thaw		= ufshcd_pci_resume,
>> -	.poweroff	= ufshcd_pci_poweroff,
>>  	.restore	= ufshcd_pci_resume,
>
>Can use SET_SYSTEM_SLEEP_PM_OPS(ufshcd_pci_suspend, ufshcd_pci_resume) for
>the ones above.
>
>> +	.prepare	 = ufshcd_suspend_prepare,
>> +	.complete	= ufshcd_resume_complete,
>>  #endif
>>  	SET_RUNTIME_PM_OPS(ufshcd_pci_runtime_suspend,
>>  			   ufshcd_pci_runtime_resume,
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> index 45624c7..0e8e76a 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;
>> @@ -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);
>> +		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)
>> +			return;
>> +
>> +		pm_runtime_put_noidle(&hba->sdev_ufs_device->sdev_gendev);
>> +		pm_runtime_mark_last_busy(&hba->sdev_ufs_device->sdev_gendev);
>> +	} 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;
>>  }
>>
>> @@ -4985,15 +5036,9 @@ 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 +5634,8 @@ 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 +5652,6 @@ 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 +5667,6 @@ 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;
>>  }
>>
>> @@ -7210,8 +7246,7 @@ static inline void ufshcd_blk_pm_runtime_init(struct scsi_device *sdev)
>>  	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, 0);
>>  	scsi_autopm_put_device(sdev);
>>  }
>>
>> @@ -7254,6 +7289,15 @@ static int ufshcd_scsi_add_wlus(struct ufs_hba *hba)
>>  		goto out;
>>  	}
>>  	ufshcd_blk_pm_runtime_init(hba->sdev_ufs_device);
>> +	/*
>> +	 * A pm_runtime_put_sync is invoked when this device enables blk_pm_runtime
>> +	 * & would suspend the device-wlun upon timer expiry.
>> +	 * But suspending device wlun _may_ put the ufs device in the pre-defined
>> +	 * low power mode (SSU <rpm_lvl>). Probing of other luns may fail then.
>> +	 * Don't allow this suspend until all the luns have been probed.
>> +	 * See pm_runtime_mark_last_busy in ufshcd_setup_links.
>> +	 */
>> +	pm_runtime_get_noresume(&hba->sdev_ufs_device->sdev_gendev);
>>  	scsi_device_put(hba->sdev_ufs_device);
>>
>>  	hba->sdev_rpmb = __scsi_add_device(hba->host, 0, 0,
>> @@ -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) {
>> @@ -7964,6 +8012,7 @@ static void ufshcd_async_scan(void *data, async_cookie_t cookie)
>>  		pm_runtime_put_sync(hba->dev);
>>  		ufshcd_hba_exit(hba);
>>  	}
>> +	hba->init_done = true;
>>  }
>>
>>  static const struct attribute_group *ufshcd_driver_groups[] = {
>> @@ -8475,7 +8524,8 @@ 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;
>>
>> @@ -8650,31 +8700,20 @@ 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;
>>  	enum ufs_pm_level pm_lvl;
>>  	enum ufs_dev_pwr_mode req_dev_pwr_mode;
>>  	enum uic_link_state req_link_state;
>>
>> -	hba->pm_op_in_progress = 1;
>> +	/*
>> +	 * Is invoked when the device wlun is added to sysfs
>> +	 * But by then hba->sdev_ufs_device may not be initialized.
>> +	 */
>> +	if (!hba->init_done)
>> +		return 0;
>> +	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;
>> @@ -8690,24 +8729,23 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>  	 * just gate the clocks.
>>  	 */
>>  	ufshcd_hold(hba, false);
>> -	hba->clk_gating.is_suspended = true;
>>
>>  	if (ufshcd_is_clkscaling_supported(hba))
>>  		ufshcd_clk_scaling_suspend(hba, true);
>>
>>  	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 +8757,7 @@ 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);
>> @@ -8746,10 +8784,213 @@ 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;
>> +			if (!ret)
>> +				goto out;
>>  		}
>>  	}
>> +enable_scaling:
>> +	if (ufshcd_is_clkscaling_supported(hba))
>> +		ufshcd_clk_scaling_suspend(hba, false);
>> +
>> +	hba->dev_info.b_rpm_dev_flush_capable = false;
>> +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));
>> +	}
>> +	if (ret)
>> +		ufshcd_update_evt_hist(hba, UFS_EVT_WL_SUSP_ERR, (u32)ret);
>> +	ufshcd_release(hba);
>> +	hba->pm_op_in_progress = false;
>> +	return ret;
>> +}
>> +
>> +static int __ufshcd_wl_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>> +{
>> +	int ret = 0;
>> +
>> +	if (!hba->init_done)
>> +		return 0;
>> +
>> +	hba->pm_op_in_progress = true;
>> +	ufshcd_hold(hba, false);
>> +	if (ufshcd_is_ufs_dev_deepsleep(hba)) {
>> +		/* The device is in DeepSleep but hba was not suspended */
>> +		ret = ufshcd_reset_and_restore(hba);
>> +		if (ret)
>> +			goto out;
>> +	}
>> +
>> +	if (!ufshcd_is_ufs_dev_active(hba)) {
>> +		ret = ufshcd_set_dev_pwr_mode(hba, UFS_ACTIVE_PWR_MODE);
>> +		if (ret)
>> +			goto out;
>> +	}
>> +
>> +	if (ufshcd_keep_autobkops_enabled_except_suspend(hba))
>> +		ufshcd_enable_auto_bkops(hba);
>> +	else
>> +		/*
>> +		 * If BKOPs operations are urgently needed at this moment then
>> +		 * keep auto-bkops enabled or else disable it.
>> +		 */
>> +		ufshcd_urgent_bkops(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);
>> +	}
>> +
>> +out:
>> +	if (ret)
>> +		ufshcd_update_evt_hist(hba, UFS_EVT_WL_RES_ERR, (u32)ret);
>> +	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
>> + * @pm_op: desired low power operation type
>> + *
>> + * This function will try to put the UFS 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
>> + * link is powered off.
>> + *
>> + * Returns 0 for success and non-zero for failure
>> + */
>> +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;
>> +
>> +	hba->pm_op_in_progress = 1;
>> +	if (!ufshcd_is_shutdown_pm(pm_op)) {
>> +		pm_lvl = ufshcd_is_runtime_pm(pm_op) ?
>> +			 hba->rpm_lvl : hba->spm_lvl;
>> +		req_dev_pwr_mode = ufs_get_pm_lvl_to_dev_pwr_mode(pm_lvl);
>> +		req_link_state = ufs_get_pm_lvl_to_link_pwr_state(pm_lvl);
>> +	} else {
>> +		req_dev_pwr_mode = UFS_POWERDOWN_PWR_MODE;
>> +		req_link_state = UIC_LINK_OFF_STATE;
>> +	}
>> +
>> +	/*
>> +	 * If we can't transition into any of the low power modes
>> +	 * just gate the clocks.
>> +	 */
>> +	ufshcd_hold(hba, false);
>> +	hba->clk_gating.is_suspended = true;
>>
>>  	/*
>>  	 * In the case of DeepSleep, the device is expected to remain powered
>> @@ -8758,9 +8999,8 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>  	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;
>> +		goto enable_gating;
>>
>> -disable_clks:
>>  	/*
>>  	 * Call vendor specific suspend callback. As these callbacks may access
>>  	 * vendor specific host controller register space call them before the
>> @@ -8790,7 +9030,6 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>  	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
>> @@ -8804,28 +9043,15 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>  		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_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:
>> -	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)
>> @@ -8846,10 +9072,8 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>  static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>  {
>>  	int ret;
>> -	enum uic_link_state old_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);
>> @@ -8901,43 +9125,14 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>  			goto vendor_suspend;
>>  	}
>
>The ufshcd_reset_and_restore() in ufshcd_resume() will also change the power
>mode of the UFS device to active.  Until the UFS device is also resumed and
>then suspended, it will not return to a low power mode.
>
>
Umm, sorry, I didn't understand this comment.
Say, the UFS device was reset in ufshcd_reset_and_restore() it'd be a hardware
reset and the UFS device would move to Powered On mode and then to Active power
mode, when it is ready to begin initialization. And from this state it should
move to all other legal states.
Before entering system suspend ufshcd_system_suspend(), the ufs device is
runtime resumed in ufshcd_suspend_prepare().

Please can you explain a bit more on this issue that you see?

I'll address the rest of the comments on the next version.

>It looks like the link state transations should also be moved to
>__ufshcd_wl_suspend / resume ?
>
>>
>> -	if (!ufshcd_is_ufs_dev_active(hba)) {
>> -		ret = ufshcd_set_dev_pwr_mode(hba, UFS_ACTIVE_PWR_MODE);
>> -		if (ret)
>> -			goto set_old_link_state;
>> -	}
>> -
>> -	if (ufshcd_keep_autobkops_enabled_except_suspend(hba))
>> -		ufshcd_enable_auto_bkops(hba);
>> -	else
>> -		/*
>> -		 * If BKOPs operations are urgently needed at this moment then
>> -		 * keep auto-bkops enabled or else disable it.
>> -		 */
>> -		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->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);
>>
>>  	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:
>> @@ -9477,15 +9672,164 @@ 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;
>> +}
>> +
>> +static int ufshcd_wl_remove(struct device *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) {
>> +		pr_err("Register device wlun driver failed: %d\n",
>> +			ret);
>
>The driver_register has some error messages, so I am not sure we need this
>message.
>
>> +		return ret;
>> +	}
>> +
>> +	ret = scsi_register_driver(&ufs_rpmb_wlun_template.gendrv);
>> +	if (ret) {
>> +		pr_err("Register rpmb wlun driver failed: %d\n",
>> +			ret);
>
>Ditto the message, but also need to unregister &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..e246ec3 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 +844,8 @@ struct ufs_hba {
>>  #ifdef CONFIG_DEBUG_FS
>>  	struct dentry *debugfs_root;
>>  #endif
>> +	bool init_done;
>> +	u32 luns_avail;
>>  };
>>
>>  /* Returns true if clocks can be gated. Otherwise false */
>> @@ -1100,6 +1105,8 @@ 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,
>>
>

On 1/03/21 8:10 pm, Asutosh Das wrote:
> On Mon, Mar 01 2021 at 05:23 -0800, Adrian Hunter wrote:
>> On 26/02/21 1:37 am, Asutosh Das wrote:
>>> @@ -8901,43 +9125,14 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
>>>              goto vendor_suspend;
>>>      }
>>
>> The ufshcd_reset_and_restore() in ufshcd_resume() will also change the power
>> mode of the UFS device to active.  Until the UFS device is also resumed and
>> then suspended, it will not return to a low power mode.
>>
>>
> Umm, sorry, I didn't understand this comment.
> Say, the UFS device was reset in ufshcd_reset_and_restore() it'd be a hardware
> reset and the UFS device would move to Powered On mode and then to Active power
> mode, when it is ready to begin initialization. And from this state it should
> move to all other legal states.
> Before entering system suspend ufshcd_system_suspend(), the ufs device is
> runtime resumed in ufshcd_suspend_prepare().
> 
> Please can you explain a bit more on this issue that you see?

Say you runtime resume the host controller, and
ufshcd_reset_and_restore() makes the UFS device active,
but the UFS device is still runtime suspended.


Example:

Add a debugfs file to show the current power mode:

diff --git a/drivers/scsi/ufs/ufs-debugfs.c b/drivers/scsi/ufs/ufs-debugfs.c
index dee98dc72d29..700b88df0866 100644
--- a/drivers/scsi/ufs/ufs-debugfs.c
+++ b/drivers/scsi/ufs/ufs-debugfs.c
@@ -48,6 +48,7 @@ void ufs_debugfs_hba_init(struct ufs_hba *hba)
 {
        hba->debugfs_root = debugfs_create_dir(dev_name(hba->dev), ufs_debugfs_root);
        debugfs_create_file("stats", 0400, hba->debugfs_root, hba, &ufs_debugfs_stats_fops);
+       debugfs_create_u32("curr_dev_pwr_mode", 0400, hba->debugfs_root, (u32 *)&hba->curr_dev_pwr_mode);
 }

 void ufs_debugfs_hba_exit(struct ufs_hba *hba)


# grep -H . /sys/bus/pci/drivers/ufshcd/0000\:00\:12.5/rpm*
/sys/bus/pci/drivers/ufshcd/0000:00:12.5/rpm_lvl:6
/sys/bus/pci/drivers/ufshcd/0000:00:12.5/rpm_target_dev_state:DEEPSLEEP
/sys/bus/pci/drivers/ufshcd/0000:00:12.5/rpm_target_link_state:OFF
# cat /sys/kernel/debug/ufshcd/0000\:00\:12.5/curr_dev_pwr_mode
4
# echo on > /sys/devices/pci0000:00/0000:00:12.5/power/control
# cat /sys/kernel/debug/ufshcd/0000\:00\:12.5/curr_dev_pwr_mode
1
# grep -H . /sys/bus/pci/drivers/ufshcd/0000\:00\:12.5/host*/target*/*/power/runtime_status
/sys/bus/pci/drivers/ufshcd/0000:00:12.5/host1/target1:0:0/1:0:0:0/power/runtime_status:suspended
/sys/bus/pci/drivers/ufshcd/0000:00:12.5/host1/target1:0:0/1:0:0:49456/power/runtime_status:suspended
/sys/bus/pci/drivers/ufshcd/0000:00:12.5/host1/target1:0:0/1:0:0:49476/power/runtime_status:suspended
/sys/bus/pci/drivers/ufshcd/0000:00:12.5/host1/target1:0:0/1:0:0:49488/power/runtime_status:suspended

So UFS devices is runtime suspended and should in DeepSleep, but it is active.