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From:   Avri Altman <Avri.Altman@wdc.com>
To:     Stanley Chu <stanley.chu@mediatek.com>,
        "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
        "martin.petersen@oracle.com" <martin.petersen@oracle.com>,
        "alim.akhtar@samsung.com" <alim.akhtar@samsung.com>,
        "jejb@linux.ibm.com" <jejb@linux.ibm.com>
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        "cc.chou@mediatek.com" <cc.chou@mediatek.com>,
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Subject: RE: [PATCH v1 1/2] scsi: ufs: Support WriteBooster on Samsung UFS
 devices
Thread-Topic: [PATCH v1 1/2] scsi: ufs: Support WriteBooster on Samsung UFS
 devices
Thread-Index: AQHWNpT3Vi/TzAb5lEy8ZsLwGGZsRajBERRQ
Date:   Sat, 30 May 2020 20:37:57 +0000
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References: <20200530151337.6182-1-stanley.chu@mediatek.com>
 <20200530151337.6182-2-stanley.chu@mediatek.com>
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=20
> @@ -2801,11 +2801,17 @@ int ufshcd_query_flag(struct ufs_hba *hba, enum
> query_opcode opcode,
>  {
>         struct ufs_query_req *request =3D NULL;
>         struct ufs_query_res *response =3D NULL;
> -       int err, selector =3D 0;
> +       int err;
>         int timeout =3D QUERY_REQ_TIMEOUT;
> +       u8 selector =3D 0;
>=20
>         BUG_ON(!hba);
>=20
> +       if (hba->dev_quirks & UFS_DEVICE_QUIRK_WB_SPECIAL_SELECTOR) {
> +               if (ufshcd_is_wb_flags(idn))
> +                       selector =3D 1;
> +       }
> +
Why not make the caller set the applicable selector,
Instead of checking this for every flag?

>         ufshcd_hold(hba, false);
>         mutex_lock(&hba->dev_cmd.lock);
>         ufshcd_init_query(hba, &request, &response, opcode, idn, index,
> @@ -2882,6 +2888,11 @@ int ufshcd_query_attr(struct ufs_hba *hba, enum
> query_opcode opcode,
>                 goto out;
>         }
>=20
> +       if (hba->dev_quirks & UFS_DEVICE_QUIRK_WB_SPECIAL_SELECTOR) {
> +               if (ufshcd_is_wb_attrs(idn))
> +                       selector =3D 1;
> +       }
> +
Same here

>         mutex_lock(&hba->dev_cmd.lock);
>         ufshcd_init_query(hba, &request, &response, opcode, idn, index,
>                         selector);
> @@ -3042,6 +3053,11 @@ int ufshcd_query_descriptor_retry(struct ufs_hba
> *hba,
>         int err;
>         int retries;
>=20
> +       if (hba->dev_quirks & UFS_DEVICE_QUIRK_WB_SPECIAL_SELECTOR) {
> +               if (ufshcd_is_wb_desc(idn, index))
> +                       selector =3D 1;
> +       }
> +
And here.
But this can't be true -=20
Are you setting the selector =3D 1 for reading any field for those descript=
ors?
Shouldn't it be for the wb specific fields?
=20

>         for (retries =3D QUERY_REQ_RETRIES; retries > 0; retries--) {
>                 err =3D __ufshcd_query_descriptor(hba, opcode, idn, index=
,
>                                                 selector, desc_buf, buf_l=
en);
> @@ -6907,8 +6923,10 @@ static int ufs_get_device_desc(struct ufs_hba *hba=
)
>         size_t buff_len;
>         u8 model_index;
>         u8 *desc_buf;
> +       u8 retry_cnt =3D 0;
>         struct ufs_dev_info *dev_info =3D &hba->dev_info;
>=20
> +retry:
>         buff_len =3D max_t(size_t, hba->desc_size.dev_desc,
>                          QUERY_DESC_MAX_SIZE + 1);
>         desc_buf =3D kmalloc(buff_len, GFP_KERNEL);
> @@ -6948,6 +6966,29 @@ static int ufs_get_device_desc(struct ufs_hba *hba=
)
>=20
>         ufs_fixup_device_setup(hba);
>=20
> +       if (!retry_cnt && (hba->dev_quirks &
> +               UFS_DEVICE_QUIRK_WB_SPECIAL_SELECTOR)) {
If you only want to enter this clause once - you should use something other=
 than retry_cnt,
Which the reader expects to performs retries....

Also, this is becoming too wired -=20
From your commit log I get that for specific Samsung devices,
You need to query wb descriptor fields/attributes/flags using selectore =3D=
 1.
But what it has to do with descriptor sizes?

> +               /*
> +                * Update WriteBooster related descriptor length with spe=
cific
> +                * seletor used.
> +                */
> +               ufshcd_read_desc_length(hba, QUERY_DESC_IDN_DEVICE, 0,
> +                                       &hba->desc_size.dev_desc);
> +               ufshcd_read_desc_length(hba, QUERY_DESC_IDN_CONFIGURATION=
,
> 0,
> +                                       &hba->desc_size.conf_desc);
> +               ufshcd_read_desc_length(hba, QUERY_DESC_IDN_UNIT, 0,
> +                                       &hba->desc_size.unit_desc);
> +               ufshcd_read_desc_length(hba, QUERY_DESC_IDN_GEOMETRY, 0,
> +                                       &hba->desc_size.geom_desc);
> +               /*
> +                * Read device descriptor again with specific selector us=
ed to
> +                * get WriteBooster related fileds.
> +                */
> +               kfree(desc_buf);
> +               retry_cnt++;
> +               goto retry;
> +       }
> +
>         /*
>          * Probe WB only for UFS-3.1 devices or UFS devices with quirk
>          * UFS_DEVICE_QUIRK_SUPPORT_EXTENDED_FEATURES enabled
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> index bf97d616e597..d850c47e8ae0 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -876,6 +876,26 @@ static inline u8 ufshcd_wb_get_query_index(struct
> ufs_hba *hba)
>         return 0;
>  }
>=20
> +static inline bool ufshcd_is_wb_attrs(enum attr_idn idn)
> +{
> +       return ((idn >=3D QUERY_ATTR_IDN_WB_FLUSH_STATUS) &&
> +               (idn <=3D QUERY_ATTR_IDN_CURR_WB_BUFF_SIZE));
> +}
> +
> +static inline bool ufshcd_is_wb_desc(enum desc_idn idn, u8 index)
> +{
> +       return (idn <=3D QUERY_DESC_IDN_CONFIGURATION) ||
> +               ((idn =3D=3D QUERY_DESC_IDN_UNIT) &&
> +               (index !=3D UFS_UPIU_RPMB_QUERY_INDEX)) ||
> +               (idn =3D=3D QUERY_DESC_IDN_GEOMETRY);
> +}
> +
> +static inline bool ufshcd_is_wb_flags(enum flag_idn idn)
> +{
> +       return ((idn >=3D QUERY_FLAG_IDN_WB_EN) &&
> +               (idn <=3D QUERY_FLAG_IDN_WB_BUFF_FLUSH_DURING_HIBERN8));
> +}
> +
>  extern int ufshcd_runtime_suspend(struct ufs_hba *hba);
>  extern int ufshcd_runtime_resume(struct ufs_hba *hba);
>  extern int ufshcd_runtime_idle(struct ufs_hba *hba);
> --
> 2.18.0