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Date:   Thu, 23 Jul 2020 10:45:04 +0800
From:   hongwus@codeaurora.org
To:     Can Guo <cang@codeaurora.org>
Cc:     asutoshd@codeaurora.org, nguyenb@codeaurora.org,
        rnayak@codeaurora.org, sh425.lee@samsung.com,
        linux-scsi@vger.kernel.org, kernel-team@android.com,
        saravanak@google.com, salyzyn@google.com,
        Alim Akhtar <alim.akhtar@samsung.com>,
        Avri Altman <avri.altman@wdc.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Stanley Chu <stanley.chu@mediatek.com>,
        Bean Huo <beanhuo@micron.com>,
        Bart Van Assche <bvanassche@acm.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 1/9] scsi: ufs: Add checks before setting clk-gating
 states
In-Reply-To: <1595471649-25675-2-git-send-email-cang@codeaurora.org>
References: <1595471649-25675-1-git-send-email-cang@codeaurora.org>
 <1595471649-25675-2-git-send-email-cang@codeaurora.org>
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On 2020-07-23 10:34, Can Guo wrote:
> Clock gating features can be turned on/off selectively which means its
> state information is only important if it is enabled. This change makes
> sure that we only look at state of clk-gating if it is enabled.
> 
> Signed-off-by: Can Guo <cang@codeaurora.org>
> Reviewed-by: Avri Altman <avri.altman@wdc.com>
> ---
>  drivers/scsi/ufs/ufshcd.c | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index cdff7e5..99bd3e4 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -1839,6 +1839,8 @@ static void ufshcd_init_clk_gating(struct ufs_hba 
> *hba)
>  	if (!ufshcd_is_clkgating_allowed(hba))
>  		return;
> 
> +	hba->clk_gating.state = CLKS_ON;
> +
>  	hba->clk_gating.delay_ms = 150;
>  	INIT_DELAYED_WORK(&hba->clk_gating.gate_work, ufshcd_gate_work);
>  	INIT_WORK(&hba->clk_gating.ungate_work, ufshcd_ungate_work);
> @@ -2541,7 +2543,8 @@ static int ufshcd_queuecommand(struct Scsi_Host
> *host, struct scsi_cmnd *cmd)
>  		err = SCSI_MLQUEUE_HOST_BUSY;
>  		goto out;
>  	}
> -	WARN_ON(hba->clk_gating.state != CLKS_ON);
> +	WARN_ON(ufshcd_is_clkgating_allowed(hba) &&
> +		(hba->clk_gating.state != CLKS_ON));
> 
>  	lrbp = &hba->lrb[tag];
> 
> @@ -8315,8 +8318,11 @@ static int ufshcd_suspend(struct ufs_hba *hba,
> enum ufs_pm_op pm_op)
>  		/* If link is active, device ref_clk can't be switched off */
>  		__ufshcd_setup_clocks(hba, false, true);
> 
> -	hba->clk_gating.state = CLKS_OFF;
> -	trace_ufshcd_clk_gating(dev_name(hba->dev), hba->clk_gating.state);
> +	if (ufshcd_is_clkgating_allowed(hba)) {
> +		hba->clk_gating.state = CLKS_OFF;
> +		trace_ufshcd_clk_gating(dev_name(hba->dev),
> +					hba->clk_gating.state);
> +	}
> 
>  	/* Put the host controller in low power mode if possible */
>  	ufshcd_hba_vreg_set_lpm(hba);
> @@ -8456,6 +8462,11 @@ static int ufshcd_resume(struct ufs_hba *hba,
> enum ufs_pm_op pm_op)
>  	if (hba->clk_scaling.is_allowed)
>  		ufshcd_suspend_clkscaling(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);
> +	}
>  out:
>  	hba->pm_op_in_progress = 0;
>  	if (ret)


Reviewed-by: Hongwu Su <hongwus@codeaurora.org>