linux-kernel - Re: [PATCH v5 06/10] scsi: ufs: ufs-qcom: Limit HS-G5 Rate-A to hosts with HW version 5

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Message-ID: <20231128055520.GG3088@thinkpad>
Date:   Tue, 28 Nov 2023 11:25:20 +0530
From:   Manivannan Sadhasivam <mani@...nel.org>
To:     Can Guo <quic_cang@...cinc.com>
Cc:     bvanassche@....org, adrian.hunter@...el.com, beanhuo@...ron.com,
        avri.altman@....com, junwoo80.lee@...sung.com,
        martin.petersen@...cle.com, linux-scsi@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 06/10] scsi: ufs: ufs-qcom: Limit HS-G5 Rate-A to
 hosts with HW version 5

On Thu, Nov 23, 2023 at 12:46:26AM -0800, Can Guo wrote:
> Qcom UFS hosts, with HW ver 5, can only support up to HS-G5 Rate-A due to
> HW limitations. If the HS-G5 PHY gear is used, update host_params->hs_rate
> to Rate-A, so that the subsequent power mode changes shall stick to Rate-A.
> 
> Signed-off-by: Can Guo <quic_cang@...cinc.com>

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

One question below...

> ---
>  drivers/ufs/host/ufs-qcom.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index 9613ad9..6756f8d 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -442,9 +442,25 @@ static u32 ufs_qcom_get_hs_gear(struct ufs_hba *hba)
>  static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
>  {
>  	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
> +	struct ufs_host_params *host_params = &host->host_params;
>  	struct phy *phy = host->generic_phy;
> +	enum phy_mode mode;
>  	int ret;
>  
> +	/*
> +	 * HW ver 5 can only support up to HS-G5 Rate-A due to HW limitations.
> +	 * If the HS-G5 PHY gear is used, update host_params->hs_rate to Rate-A,
> +	 * so that the subsequent power mode change shall stick to Rate-A.
> +	 */
> +	if (host->hw_ver.major == 0x5) {
> +		if (host->phy_gear == UFS_HS_G5)
> +			host_params->hs_rate = PA_HS_MODE_A;
> +		else
> +			host_params->hs_rate = PA_HS_MODE_B;

Is this 'else' part really needed? Since there wouldn't be any 2nd init, I think
we can skip that.

- Mani

> +	}
> +
> +	mode = host_params->hs_rate == PA_HS_MODE_B ? PHY_MODE_UFS_HS_B : PHY_MODE_UFS_HS_A;
> +
>  	/* Reset UFS Host Controller and PHY */
>  	ret = ufs_qcom_host_reset(hba);
>  	if (ret)
> @@ -459,7 +475,7 @@ static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
>  		return ret;
>  	}
>  
> -	phy_set_mode_ext(phy, PHY_MODE_UFS_HS_B, host->phy_gear);
> +	phy_set_mode_ext(phy, mode, host->phy_gear);
>  
>  	/* power on phy - start serdes and phy's power and clocks */
>  	ret = phy_power_on(phy);
> -- 
> 2.7.4
> 

-- 
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