linux-kernel - RE: [PATCH RESEND] scsi: ufs: Add checking lifetime attribute for WriteBooster

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Date:   Fri, 28 Jan 2022 16:15:26 +0000
From:   Avri Altman <Avri.Altman@....com>
To:     "j-young.choi@...sung.com" <j-young.choi@...sung.com>,
        ALIM AKHTAR <alim.akhtar@...sung.com>,
        "jejb@...ux.ibm.com" <jejb@...ux.ibm.com>,
        "martin.petersen@...cle.com" <martin.petersen@...cle.com>,
        "bvanassche@....org" <bvanassche@....org>,
        "cang@...eaurora.org" <cang@...eaurora.org>,
        "adrian.hunter@...el.com" <adrian.hunter@...el.com>,
        "asutoshd@...eaurora.org" <asutoshd@...eaurora.org>,
        "linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "huobean@...il.com" <huobean@...il.com>
Subject: RE: [PATCH RESEND] scsi: ufs: Add checking lifetime attribute for
 WriteBooster

> Because WB performs write in SLC mode, it is difficult to use WB infinitely.
> 
> Vendors can set the Lifetime limit value to the device.
> If Lifetime exceeds the limit value, the device itself can disable the WB feature.
> 
> WB feature supports "bWriteBoosterBufferLifeTimeEst (IDN = 1E)" attribute.
> 
> With Lifetime exceeding the limit value, the current driver continuously performs
> the following query.
> 
>         - Write Flag: WB_ENABLE / DISABLE
>         - Read attr: Available Buffer Size
>         - Read attr: Current Buffer Size
> 
> This patch recognizes that WriteBooster is no longer supported by the device,
> and prevent unnecessary query issues.
> 
> Signed-off-by: Jinyoung Choi <j-young.choi@...sung.com>
Acked-by: Avri Altman <avri.altman@....com>

> ---
>  drivers/scsi/ufs/ufs.h    |  6 +++++
>  drivers/scsi/ufs/ufshcd.c | 52 +++++++++++++++++++++++++++++++++++++++
>  2 files changed, 58 insertions(+)
> 
> diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h index
> 0bfdca3e648e..4a00c24a3209 100644
> --- a/drivers/scsi/ufs/ufs.h
> +++ b/drivers/scsi/ufs/ufs.h
> @@ -43,6 +43,12 @@
>  /* WriteBooster buffer is available only for the logical unit from 0 to 7 */
> #define UFS_UPIU_MAX_WB_LUN_ID 8
> 
> +/*
> + * WriteBooster buffer lifetime has a limit setted by vendor.
> + * If it is over the limit, WriteBooster feature will be disabled.
> + */
> +#define UFS_WB_EXCEED_LIFETIME         0x0B
> +
>  /* Well known logical unit id in LUN field of UPIU */  enum {
>         UFS_UPIU_REPORT_LUNS_WLUN       = 0x81,
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index
> 460d2b440d2e..41d85b69fa50 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -5778,6 +5778,47 @@ static bool
> ufshcd_wb_presrv_usrspc_keep_vcc_on(struct ufs_hba *hba,
>         return false;
>  }
> 
> +static void ufshcd_wb_force_disable(struct ufs_hba *hba) {
> +       if (!(hba->quirks & UFSHCI_QUIRK_SKIP_MANUAL_WB_FLUSH_CTRL))
> +               ufshcd_wb_toggle_flush(hba, false);
> +
> +       ufshcd_wb_toggle_flush_during_h8(hba, false);
> +       ufshcd_wb_toggle(hba, false);
> +       hba->caps &= ~UFSHCD_CAP_WB_EN;
> +
> +       dev_info(hba->dev, "%s: WB force disabled\n", __func__); }
> +
> +static bool ufshcd_is_wb_buf_lifetime_available(struct ufs_hba *hba) {
> +       u32 lifetime;
> +       int ret;
> +       u8 index;
> +
> +       index = ufshcd_wb_get_query_index(hba);
> +       ret = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,
> +                                     QUERY_ATTR_IDN_WB_BUFF_LIFE_TIME_EST,
> +                                     index, 0, &lifetime);
> +       if (ret) {
> +               dev_err(hba->dev,
> +                       "%s: bWriteBoosterBufferLifeTimeEst read failed %d\n",
> +                       __func__, ret);
> +               return false;
> +       }
> +
> +       if (lifetime == UFS_WB_EXCEED_LIFETIME) {
> +               dev_err(hba->dev, "%s: WB buf lifetime is exhausted 0x%02X\n",
> +                       __func__, lifetime);
> +               return false;
> +       }
> +
> +       dev_dbg(hba->dev, "%s: WB buf lifetime is 0x%02X\n",
> +               __func__, lifetime);
> +
> +       return true;
> +}
> +
>  static bool ufshcd_wb_need_flush(struct ufs_hba *hba)  {
>         int ret;
> @@ -5786,6 +5827,12 @@ static bool ufshcd_wb_need_flush(struct ufs_hba
> *hba)
> 
>         if (!ufshcd_is_wb_allowed(hba))
>                 return false;
> +
> +       if (!ufshcd_is_wb_buf_lifetime_available(hba)) {
> +               ufshcd_wb_force_disable(hba);
> +               return false;
> +       }
> +
>         /*
>          * The ufs device needs the vcc to be ON to flush.
>          * With user-space reduction enabled, it's enough to enable flush @@ -
> 7486,6 +7533,7 @@ static void ufshcd_wb_probe(struct ufs_hba *hba, u8
> *desc_buf)
> 
>         if (!ufshcd_is_wb_allowed(hba))
>                 return;
> +
>         /*
>          * Probe WB only for UFS-2.2 and UFS-3.1 (and later) devices or
>          * UFS devices with quirk
> UFS_DEVICE_QUIRK_SUPPORT_EXTENDED_FEATURES
> @@ -7537,6 +7585,10 @@ static void ufshcd_wb_probe(struct ufs_hba *hba,
> u8 *desc_buf)
>                 if (!d_lu_wb_buf_alloc)
>                         goto wb_disabled;
>         }
> +
> +       if (!ufshcd_is_wb_buf_lifetime_available(hba))
> +               goto wb_disabled;
> +
>         return;
> 
>  wb_disabled:
> --
> 2.25.1