Hi,
>
> When you set uic_link_state during sleep statae to
> UIC_LINK_OFF_STATE, UFS driver does interface initialization
> that is a series of some steps including fDeviceInit and thus,
> You might feel that its latency is a little bit longer.
>
> This patch is run it asynchronously to reduce system wake-up time.
Can you share your initial testing findings?
How much time does it save?
>
> Signed-off-by: Kiwoong Kim <kwmad.kim@xxxxxxxxxxx>
> ---
> drivers/scsi/ufs/Kconfig | 10 ++++
> drivers/scsi/ufs/ufshcd.c | 120 ++++++++++++++++++++++++++++++++++---------
> ---
> 2 files changed, 100 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig
> index 8cd9026..723e7cb 100644
> --- a/drivers/scsi/ufs/Kconfig
> +++ b/drivers/scsi/ufs/Kconfig
> @@ -172,3 +172,13 @@ config SCSI_UFS_EXYNOS
>
> Select this if you have UFS host controller on EXYNOS chipset.
> If unsure, say N.
> +
> +config SCSI_UFSHCD_ASYNC_INIT
> + bool "Asynchronous UFS interface initialization support"
> + depends on SCSI_UFSHCD
> + default n
> + ---help---
> + This selects the support of doing UFS interface initialization
> + asynchronously when you set link state to link off,
> + i.e. UIC_LINK_OFF_STATE, to reduce system wake-up time.
> + Select this if you have UFS Host Controller.
Maybe replace this config switch with platform capability?
So each platform vendor can choose if he is using a sync vs async init?
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 52abe82..b65d38c 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -8319,6 +8319,80 @@ static int ufshcd_suspend(struct ufs_hba *hba,
> enum ufs_pm_op pm_op)
> return ret;
> }
>
> +static int ufshcd_post_resume(struct ufs_hba *hba)
Why do you need to move this code around?
If its async - then there is no shared code -
you go through the full init flow, and just goto out?
> +{
> + int ret;
> +
> + 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);
> +
> + hba->clk_gating.is_suspended = false;
> +
> + if (hba->clk_scaling.is_allowed)
> + ufshcd_resume_clkscaling(hba);
> +
> + /* 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);
> + }
> +
> + /* Schedule clock gating in case of no access to UFS device yet */
> + ufshcd_release(hba);
> +out:
> + return ret;
> +}
> +
> +#if defined(SCSI_UFSHCD_ASYNC_INIT)
> +static void ufshcd_async_resume(void *data, async_cookie_t cookie)
> +{
> + struct ufs_hba *hba = (struct ufs_hba *)data;
> + unsigned long flags;
> + int ret = 0;
> + int retries = 2;
> +
> + /* transition to block requests */
> + spin_lock_irqsave(hba->host->host_lock, flags);
> + hba->ufshcd_state = UFSHCD_STATE_RESET;
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
> +
> + /* initialize, instead of set_old_link_state ?? */
> + do {
> + ret = ufshcd_reset_and_restore(hba);
> + if (ret) {
> + dev_err(hba->dev, "%s: reset and restore failed\n",
> + __func__);
> + spin_lock_irqsave(hba->host->host_lock, flags);
> + hba->ufshcd_state = UFSHCD_STATE_ERROR;
> + hba->pm_op_in_progress = 0;
> + spin_unlock_irqrestore(hba->host->host_lock, flags);
> + return;
> + }
> + ret = ufshcd_post_resume(hba);
> + } while (ret && --retries);
> + if (ret)
> + goto reset;
> +
> + hba->pm_op_in_progress = 0;
> + if (ret)
> + ufshcd_update_reg_hist(&hba->ufs_stats.resume_err, (u32)ret);
> +}
> +#endif
> +
> /**
> * ufshcd_resume - helper function for resume operations
> * @hba: per adapter instance
> @@ -8370,6 +8444,14 @@ static int ufshcd_resume(struct ufs_hba *hba,
> enum ufs_pm_op pm_op)
> * A full initialization of the host and the device is
> * required since the link was put to off during suspend.
> */
> +#if defined(SCSI_UFSHCD_ASYNC_INIT)
> + /*
> + * Assuems error free since ufshcd_probe_hba failure is
> + * uncorrectable.
> + */
> + ufshcd_async_schedule(ufshcd_async_resume, hba);
> + goto out_new;
> +#else
> ret = ufshcd_reset_and_restore(hba);
> /*
> * ufshcd_reset_and_restore() should have already
> @@ -8377,38 +8459,12 @@ static int ufshcd_resume(struct ufs_hba *hba,
> enum ufs_pm_op pm_op)
> */
> if (ret || !ufshcd_is_link_active(hba))
> goto vendor_suspend;
> +#endif
> }
>
> - 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 (hba->clk_scaling.is_allowed)
> - ufshcd_resume_clkscaling(hba);
> -
> - /* 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);
> - }
> -
> - /* Schedule clock gating in case of no access to UFS device yet */
> - ufshcd_release(hba);
> + ret = ufshcd_post_resume(hba);
> + if (ret)
> + goto set_old_link_state;
>
> goto out;
>
> @@ -8427,6 +8483,10 @@ static int ufshcd_resume(struct ufs_hba *hba,
> enum ufs_pm_op pm_op)
> hba->pm_op_in_progress = 0;
> if (ret)
> ufshcd_update_reg_hist(&hba->ufs_stats.resume_err, (u32)ret);
> + /* For async init, pm_op_in_progress still needs to be one */
> +#if defined(SCSI_UFSHCD_ASYNC_INIT)
> +out_new:
> +#endif
> return ret;
> }
Thanks,
Avri
>
> --
> 2.7.4
