RE: [PATCH V3 2/2] scsi: ufs: Add runtime PM support for UFS host controller driver

[Seungwon Jeon <tgih.jun@samsung.com>]

On Tue, July 09, 2013, Sujit Reddy Thumma wrote:
> Add runtime PM helpers to suspend/resume UFS controller at runtime.
> Enable runtime PM by default for pci and platform drivers as the
> initialized hardware can suspend if it is not used after bootup.
> 
> Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
> ---
>  drivers/scsi/ufs/ufshcd-pci.c    |   65 ++++++++++++++++++++++++++++++++++---
>  drivers/scsi/ufs/ufshcd-pltfrm.c |   51 +++++++++++++++++++++++++++++-
>  drivers/scsi/ufs/ufshcd.c        |    8 +++++
>  3 files changed, 117 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufshcd-pci.c b/drivers/scsi/ufs/ufshcd-pci.c
> index 48be39a..7bd8faa 100644
> --- a/drivers/scsi/ufs/ufshcd-pci.c
> +++ b/drivers/scsi/ufs/ufshcd-pci.c
> @@ -35,6 +35,7 @@
> 
>  #include "ufshcd.h"
>  #include <linux/pci.h>
> +#include <linux/pm_runtime.h>
> 
>  #ifdef CONFIG_PM
>  /**
> @@ -44,7 +45,7 @@
>   *
>   * Returns -ENOSYS
>   */
> -static int ufshcd_pci_suspend(struct pci_dev *pdev, pm_message_t state)
> +static int ufshcd_pci_suspend(struct device *dev)
>  {
>  	/*
>  	 * TODO:
> @@ -61,7 +62,7 @@ static int ufshcd_pci_suspend(struct pci_dev *pdev, pm_message_t state)
>   *
>   * Returns -ENOSYS
>   */
> -static int ufshcd_pci_resume(struct pci_dev *pdev)
> +static int ufshcd_pci_resume(struct device *dev)
>  {
>  	/*
>  	 * TODO:
> @@ -71,8 +72,48 @@ static int ufshcd_pci_resume(struct pci_dev *pdev)
> 
>  	return -ENOSYS;
>  }
> +#else
> +#define ufshcd_pci_suspend	NULL
> +#define ufshcd_pci_resume	NULL
>  #endif /* CONFIG_PM */
> 
> +#ifdef CONFIG_PM_RUNTIME
> +static int ufshcd_pci_runtime_suspend(struct device *dev)
> +{
> +	struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
> +	struct ufs_hba *hba = pci_get_drvdata(pdev);
Can be replaced:
	struct ufs_hba *hba = dev_get_drvdata(dev);

> +
> +	if (!hba)
> +		return 0;
> +
> +	return ufshcd_runtime_suspend(hba);
> +}
> +static int ufshcd_pci_runtime_resume(struct device *dev)
> +{
> +	struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
> +	struct ufs_hba *hba = pci_get_drvdata(pdev);
Same as above.


> +
> +	if (!hba)
> +		return 0;
> +
> +	return ufshcd_runtime_resume(hba);
> +}
> +static int ufshcd_pci_runtime_idle(struct device *dev)
> +{
> +	struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
> +	struct ufs_hba *hba = pci_get_drvdata(pdev);
Same as above.

> +
> +	if (!hba)
> +		return 0;
> +
> +	return ufshcd_runtime_idle(hba);
> +}
> +#else /* !CONFIG_PM_RUNTIME */
> +#define ufshcd_pci_runtime_suspend	NULL
> +#define ufshcd_pci_runtime_resume	NULL
> +#define ufshcd_pci_runtime_idle	NULL
> +#endif /* CONFIG_PM_RUNTIME */
> +
>  /**
>   * ufshcd_pci_shutdown - main function to put the controller in reset state
>   * @pdev: pointer to PCI device handle
> @@ -91,6 +132,9 @@ static void ufshcd_pci_remove(struct pci_dev *pdev)
>  {
>  	struct ufs_hba *hba = pci_get_drvdata(pdev);
> 
> +	pm_runtime_forbid(&pdev->dev);
> +	pm_runtime_get_noresume(&pdev->dev);
> +
>  	disable_irq(pdev->irq);
>  	ufshcd_remove(hba);
>  	pci_release_regions(pdev);
> @@ -168,6 +212,8 @@ ufshcd_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>  	}
> 
>  	pci_set_drvdata(pdev, hba);
> +	pm_runtime_put_noidle(&pdev->dev);
> +	pm_runtime_allow(&pdev->dev);
> 
>  	return 0;
> 
> @@ -182,6 +228,14 @@ out_error:
>  	return err;
>  }
> 
> +static const struct dev_pm_ops ufshcd_pci_pm_ops = {
> +	.suspend	= ufshcd_pci_suspend,
> +	.resume		= ufshcd_pci_resume,
> +	.runtime_suspend = ufshcd_pci_runtime_suspend,
> +	.runtime_resume  = ufshcd_pci_runtime_resume,
> +	.runtime_idle    = ufshcd_pci_runtime_idle,
> +};
> +
>  static DEFINE_PCI_DEVICE_TABLE(ufshcd_pci_tbl) = {
>  	{ PCI_VENDOR_ID_SAMSUNG, 0xC00C, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
>  	{ }	/* terminate list */
> @@ -195,10 +249,9 @@ static struct pci_driver ufshcd_pci_driver = {
>  	.probe = ufshcd_pci_probe,
>  	.remove = ufshcd_pci_remove,
>  	.shutdown = ufshcd_pci_shutdown,
> -#ifdef CONFIG_PM
> -	.suspend = ufshcd_pci_suspend,
> -	.resume = ufshcd_pci_resume,
> -#endif
> +	.driver = {
> +		.pm = &ufshcd_pci_pm_ops
> +	},
>  };
> 
>  module_pci_driver(ufshcd_pci_driver);
> diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
> index c42db40..b1f2605 100644
> --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
> +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
> @@ -34,6 +34,7 @@
>   */
> 
>  #include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> 
>  #include "ufshcd.h"
> 
> @@ -87,6 +88,43 @@ static int ufshcd_pltfrm_resume(struct device *dev)
>  #define ufshcd_pltfrm_resume	NULL
>  #endif
> 
> +#ifdef CONFIG_PM_RUNTIME
> +static int ufshcd_pltfrm_runtime_suspend(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct ufs_hba *hba =  platform_get_drvdata(pdev);
Same as above.

> +
> +	if (!hba)
> +		return 0;
> +
> +	return ufshcd_runtime_suspend(hba);
> +}
> +static int ufshcd_pltfrm_runtime_resume(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct ufs_hba *hba =  platform_get_drvdata(pdev);
Same as above.

> +
> +	if (!hba)
> +		return 0;
> +
> +	return ufshcd_runtime_resume(hba);
> +}
> +static int ufshcd_pltfrm_runtime_idle(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct ufs_hba *hba =  platform_get_drvdata(pdev);
Same as above.

> +
> +	if (!hba)
> +		return 0;
> +
> +	return ufshcd_runtime_idle(hba);
> +}
> +#else /* !CONFIG_PM_RUNTIME */
> +#define ufshcd_pltfrm_runtime_suspend	NULL
> +#define ufshcd_pltfrm_runtime_resume	NULL
> +#define ufshcd_pltfrm_runtime_idle	NULL
> +#endif /* CONFIG_PM_RUNTIME */
> +
>  /**
>   * ufshcd_pltfrm_probe - probe routine of the driver
>   * @pdev: pointer to Platform device handle
> @@ -122,14 +160,20 @@ static int ufshcd_pltfrm_probe(struct platform_device *pdev)
>  		goto out;
>  	}
> 
> +	pm_runtime_set_active(&pdev->dev);
> +	pm_runtime_enable(&pdev->dev);
> +
>  	err = ufshcd_init(dev, &hba, mmio_base, irq);
>  	if (err) {
>  		dev_err(dev, "Intialization failed\n");
> -		goto out;
> +		goto out_disable_rpm;
>  	}
> 
>  	platform_set_drvdata(pdev, hba);
> 
> +out_disable_rpm:
> +	pm_runtime_disable(&pdev->dev);
> +	pm_runtime_set_suspended(&pdev->dev);
>  out:
>  	return err;
>  }
> @@ -144,6 +188,8 @@ static int ufshcd_pltfrm_remove(struct platform_device *pdev)
>  {
>  	struct ufs_hba *hba =  platform_get_drvdata(pdev);
> 
> +	pm_runtime_get_sync(&(pdev)->dev);
> +
>  	disable_irq(hba->irq);
>  	ufshcd_remove(hba);
>  	return 0;
> @@ -157,6 +203,9 @@ static const struct of_device_id ufs_of_match[] = {
>  static const struct dev_pm_ops ufshcd_dev_pm_ops = {
>  	.suspend	= ufshcd_pltfrm_suspend,
>  	.resume		= ufshcd_pltfrm_resume,
> +	.runtime_suspend = ufshcd_pltfrm_runtime_suspend,
> +	.runtime_resume  = ufshcd_pltfrm_runtime_resume,
> +	.runtime_idle    = ufshcd_pltfrm_runtime_idle,
>  };
> 
>  static struct platform_driver ufshcd_pltfrm_driver = {
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index a25de66..af7d01d 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -2230,6 +2230,7 @@ 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);
>  	err = ufshcd_get_ee_status(hba, &status);
>  	if (err) {
>  		dev_err(hba->dev, "%s: failed to get exception status %d\n",
> @@ -2245,6 +2246,7 @@ static void ufshcd_exception_event_handler(struct work_struct *work)
>  					__func__, err);
>  	}
>  out:
> +	pm_runtime_put_sync(hba->dev);
In ufshcd_urgent_bkops, ufshcd_enable_auto_bkops will be executed.

>  	return;
>  }
> 
> @@ -2257,9 +2259,11 @@ static void ufshcd_fatal_err_handler(struct work_struct *work)
>  	struct ufs_hba *hba;
>  	hba = container_of(work, struct ufs_hba, feh_workq);
> 
> +	pm_runtime_get_sync(hba->dev);
>  	/* check if reset is already in progress */
>  	if (hba->ufshcd_state != UFSHCD_STATE_RESET)
>  		ufshcd_do_reset(hba);
> +	pm_runtime_put_sync(hba->dev);
>  }
> 
>  /**
> @@ -2562,6 +2566,7 @@ static void ufshcd_async_scan(void *data, async_cookie_t cookie)
>  	hba->auto_bkops_enabled = false;
In the end of 'ufshcd_init', pm_runtime_get_sync is called, hence auto_bkops_enabled may has false.
'auto_bkops_enabled = false' is needed?

>  	ufshcd_enable_auto_bkops(hba);
Should 'ufshcd_enable_auto_bkops' be done here?

>  	scsi_scan_host(hba->host);
> +	pm_runtime_put_sync(hba->dev);
Practically, after pm_runtime_put_sync, ufshcd_enable_auto_bkops will be executed.
Then, it's duplication of ufshcd_enable_auto_bkops?
ufshcd_enable_auto_bkops is already done above.

And actual routine of scsi_scan_host performs asynchronously.
That means it's not completed. So, pm_runtime_put_sync looks like improper here.

>  out:
>  	return;
>  }
> @@ -2783,6 +2788,9 @@ int ufshcd_init(struct device *dev, struct ufs_hba **hba_handle,
> 
>  	*hba_handle = hba;
> 
> +	/* Hold auto suspend until async scan completes */
What's meaning of comment?

Thanks,
Seungwon Jeon

> +	pm_runtime_get_sync(dev);
> +
>  	async_schedule(ufshcd_async_scan, hba);
> 
>  	return 0;
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation.
> 
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