linux-kernel - Re: [PATCH v2] scsi: ufs: qcom: avoid re-init quirk when gears match

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Message-ID: <20240124084810.GF4906@thinkpad>
Date: Wed, 24 Jan 2024 14:18:10 +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 v2] scsi: ufs: qcom: avoid re-init quirk when gears match

On Tue, Jan 23, 2024 at 02:28:57PM -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.
> 
> The REINIT quirk only applies starting with controller v4. For these,
> ufs_qcom_get_hs_gear() reads 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 REINIT
> to save some time.
> 
> Signed-off-by: Eric Chanudet <echanude@...hat.com>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>

- Mani

> ---
> 
> v1 -> v2:
> * drop test against host->hw_ver.major >= 4 and amend description as a
>   result (Andrew/Mani)
> * add comment, test device gear against host->phy_gear and reset
>   host->phy_gear only if necessary (Mani)
> * Link to v1: https://lore.kernel.org/linux-arm-msm/20240119185537.3091366-11-echanude@redhat.com/
> 
> trace_event=ufs:ufshcd_init reports the time spent in ufshcd_probe_hba
> where the re-init quirk is performed:
> Currently:
> 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 | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index 39eef470f8fa..f7dba7236c6e 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -738,8 +738,17 @@ 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)
> -			host->phy_gear = dev_req_params->gear_tx;
> +		if (hba->ufshcd_state == UFSHCD_STATE_RESET) {
> +			/*
> +			 * 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;
> +		}
>  
>  		/* 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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