linux-kernel - Re: [PATCH v8 08/10] scsi: ufs: ufs-qcom: Add support for UFS device version detection

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Message-ID: <4819834c-b861-a507-8d6c-94a05760a03d@quicinc.com>
Date:   Thu, 7 Dec 2023 14:11:43 +0530
From:   Nitin Rawat <quic_nitirawa@...cinc.com>
To:     Can Guo <quic_cang@...cinc.com>, <bvanassche@....org>,
        <mani@...nel.org>, <adrian.hunter@...el.com>, <vkoul@...nel.org>,
        <beanhuo@...ron.com>, <avri.altman@....com>,
        <junwoo80.lee@...sung.com>, <martin.petersen@...cle.com>
CC:     <linux-scsi@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        "Bao D. Nguyen" <quic_nguyenb@...cinc.com>,
        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 v8 08/10] scsi: ufs: ufs-qcom: Add support for UFS device
 version detection



On 12/2/2023 6:06 PM, Can Guo wrote:
> From: "Bao D. Nguyen" <quic_nguyenb@...cinc.com>
> 
> Start from HW ver 5, a spare register in UFS host controller is added and
> used to indicate the UFS device version. The spare register is populated by
> bootloader for now, but in future it will be populated by HW automatically
> during link startup with its best efforts in any boot stage prior to Linux.
> 
> During host driver init, read the spare register, if it is not populated
> with a UFS device version, go ahead with the dual init mechanism. If a UFS
> device version is in there, use the UFS device version together with host
> controller's HW version to decide the proper PHY gear which should be used
> to configure the UFS PHY without going through the second init.
> 
> Signed-off-by: Bao D. Nguyen <quic_nguyenb@...cinc.com>
> Signed-off-by: Can Guo <quic_cang@...cinc.com>
> ---
> 
> v7 -> v8:
> Fixed a BUG introduced from v6 -> v7. The spare register is added since HW ver 5, hence exclude HW ver == 4.
> 
> ---
>   drivers/ufs/host/ufs-qcom.c | 35 ++++++++++++++++++++++++++++-------
>   drivers/ufs/host/ufs-qcom.h |  4 ++++
>   2 files changed, 32 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index ee3f07a..968a4c0 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -1065,17 +1065,38 @@ static void ufs_qcom_advertise_quirks(struct ufs_hba *hba)
>   static void ufs_qcom_set_phy_gear(struct ufs_qcom_host *host)
>   {
>   	struct ufs_host_params *host_params = &host->host_params;
> +	u32 val, dev_major;
>   
>   	host->phy_gear = host_params->hs_tx_gear;
>   
> -	/*
> -	 * For controllers whose major HW version is < 4, power up the PHY using
> -	 * minimum supported gear (UFS_HS_G2). Switching to max gear will be
> -	 * performed during reinit if supported. For newer controllers, whose
> -	 * major HW version is >= 4, power up the PHY using max supported gear.
> -	 */
> -	if (host->hw_ver.major < 0x4)
> +	if (host->hw_ver.major < 0x4) {
> +		/*
> +		 * For controllers whose major HW version is < 4, power up the
> +		 * PHY using minimum supported gear (UFS_HS_G2). Switching to
> +		 * max gear will be performed during reinit if supported.
> +		 * For newer controllers, whose major HW version is >= 4, power
> +		 * up the PHY using max supported gear.
> +		 */
>   		host->phy_gear = UFS_HS_G2;
> +	} else if (host->hw_ver.major >= 0x5) {
> +		val = ufshcd_readl(host->hba, REG_UFS_DEBUG_SPARE_CFG);
> +		dev_major = FIELD_GET(UFS_DEV_VER_MAJOR_MASK, val);
> +
> +		/*
> +		 * Since the UFS device version is populated, let's remove the
> +		 * REINIT quirk as the negotiated gear won't change during boot.
> +		 * So there is no need to do reinit.
> +		 */
> +		if (dev_major != 0x0)
> +			host->hba->quirks &= ~UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH;
> +
> +		/*
> +		 * For UFS 3.1 device and older, power up the PHY using HS-G4
> +		 * PHY gear to save power.
> +		 */
> +		if (dev_major > 0x0 && dev_major < 0x4)
> +			host->phy_gear = UFS_HS_G4;
> +	}
>   }
>   
>   static void ufs_qcom_set_host_params(struct ufs_hba *hba)
> diff --git a/drivers/ufs/host/ufs-qcom.h b/drivers/ufs/host/ufs-qcom.h
> index 11419eb..32e51d9 100644
> --- a/drivers/ufs/host/ufs-qcom.h
> +++ b/drivers/ufs/host/ufs-qcom.h
> @@ -23,6 +23,8 @@
>   #define UFS_HW_VER_MINOR_MASK	GENMASK(27, 16)
>   #define UFS_HW_VER_STEP_MASK	GENMASK(15, 0)
>   
> +#define UFS_DEV_VER_MAJOR_MASK	GENMASK(7, 4)
> +
>   /* vendor specific pre-defined parameters */
>   #define SLOW 1
>   #define FAST 2
> @@ -54,6 +56,8 @@ enum {
>   	UFS_AH8_CFG				= 0xFC,
>   
>   	REG_UFS_CFG3				= 0x271C,
> +
> +	REG_UFS_DEBUG_SPARE_CFG			= 0x284C,
>   };
>   
>   /* QCOM UFS host controller vendor specific debug registers */

Reviewed-by: Nitin Rawat <quic_nitirawa@...cinc.com>