linux-kernel - Re: [PATCH] scsi: ufs: qcom: avoid re-init quirk when gears match

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Date: Tue, 23 Jan 2024 20:41:02 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: Eric Chanudet <echanude@...hat.com>
Cc: Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konrad.dybcio@...aro.org>,
	"James E.J. Bottomley" <jejb@...ux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@...cle.com>,
	linux-arm-msm@...r.kernel.org, linux-scsi@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] scsi: ufs: qcom: avoid re-init quirk when gears match

On Fri, Jan 19, 2024 at 01:55:47PM -0500, Eric Chanudet wrote:
> On sa8775p-ride, probing the hba will go through the
> UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH path although the power info
> are same during the second init.
> 
> If the host is at least v4, ufs_qcom_get_hs_gear() picked the highest
> supported gear when setting the host_params. After the negotiation, if
> the host and device are on the same gear, it is the highest gear
> supported between the two. Skip the re-init to save some time.
> 
> Signed-off-by: Eric Chanudet <echanude@...hat.com>
> ---
> 
> "trace_event=ufs:ufshcd_init" reports the time spent where the re-init
> quirk is performed. On sa8775p-ride:
> Baseline:
>   0.355879: ufshcd_init: 1d84000.ufs: took 103377 usecs, dev_state: UFS_ACTIVE_PWR_MODE, link_state: UIC_LINK_ACTIVE_STATE, err 0
> With this patch:
>   0.297676: ufshcd_init: 1d84000.ufs: took 43553 usecs, dev_state: UFS_ACTIVE_PWR_MODE, link_state: UIC_LINK_ACTIVE_STATE, err 0
> 
>  drivers/ufs/host/ufs-qcom.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index 39eef470f8fa..f9f161340e78 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -738,8 +738,12 @@ static int ufs_qcom_pwr_change_notify(struct ufs_hba *hba,
>  		 * the second init can program the optimal PHY settings. This allows one to start
>  		 * the first init with either the minimum or the maximum support gear.
>  		 */
> -		if (hba->ufshcd_state == UFSHCD_STATE_RESET)
> +		if (hba->ufshcd_state == UFSHCD_STATE_RESET) {
> +			if (host->hw_ver.major >= 0x4 &&

You can get rid of this check as I said in the reply.

> +			    host_params->hs_tx_gear == dev_req_params->gear_tx)

How about?

			/*
			 * Skip REINIT if the negotiated gear matches with the
			 * initial phy_gear. Otherwise, update the phy_gear to
			 * program the optimal gear setting during REINIT.
			 */
			if (host->phy_gear == dev_req_params->gear_tx)
				hba->quirks &= ~UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH;
			else
				host->phy_gear = dev_req_params->gear_tx;

- Mani

> +				hba->quirks &= ~UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH;
>  			host->phy_gear = dev_req_params->gear_tx;
> +		}
>  
>  		/* enable the device ref clock before changing to HS mode */
>  		if (!ufshcd_is_hs_mode(&hba->pwr_info) &&
> -- 
> 2.43.0
> 

-- 
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