Re: [PATCH v1 15/15] scsi: ufs: add wrapper for retrying sending query attribute

[Rob Herring]

On Aug 21, 2015 3:10 PM, "Yaniv Gardi" <ygardi@xxxxxxxxxxxxxx> wrote:
>
> Sometimes queries from the device might return a failure so it is
> recommended to retry sending the query, before giving up.
> This change adds a wrapper to retry sending a query attribute,
> in cases where we need to wait longer, before we continue,
> or before reporting a failure.

Why not just always retry? Are there cases where retrying would be a problem?


>
> Signed-off-by: Yaniv Gardi <ygardi@xxxxxxxxxxxxxx>
>
> ---
>  drivers/scsi/ufs/ufshcd.c | 51 ++++++++++++++++++++++++++++++++++++++++-------
>  1 file changed, 44 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 876148b..bfef67d 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -1827,6 +1827,43 @@ out:
>  }
>
>  /**
> + * ufshcd_query_attr_retry() - API function for sending query
> + * attribute with retries
> + * @hba: per-adapter instance
> + * @opcode: attribute opcode
> + * @idn: attribute idn to access
> + * @index: index field
> + * @selector: selector field
> + * @attr_val: the attribute value after the query request
> + * completes
> + *
> + * Returns 0 for success, non-zero in case of failure
> +*/
> +static int ufshcd_query_attr_retry(struct ufs_hba *hba,
> +       enum query_opcode opcode, enum attr_idn idn, u8 index, u8 selector,
> +       u32 *attr_val)
> +{
> +       int ret = 0;
> +       u32 retries;
> +
> +        for (retries = QUERY_REQ_RETRIES; retries > 0; retries--) {
> +               ret = ufshcd_query_attr(hba, opcode, idn, index,
> +                                               selector, attr_val);
> +               if (ret)
> +                       dev_dbg(hba->dev, "%s: failed with error %d, retries %d\n",
> +                               __func__, ret, retries);
> +               else
> +                       break;
> +       }
> +
> +       if (ret)
> +               dev_err(hba->dev,
> +                       "%s: query attribute, idn %d, failed with error %d after %d retires\n",
> +                       __func__, idn, ret, retries);

The retry count will be wrong here.

> +       return ret;
> +}
> +
> +/**
>   * ufshcd_query_descriptor - API function for sending descriptor requests
>   * hba: per-adapter instance
>   * opcode: attribute opcode
> @@ -3407,7 +3444,7 @@ static int ufshcd_disable_ee(struct ufs_hba *hba, u16 mask)
>
>         val = hba->ee_ctrl_mask & ~mask;
>         val &= 0xFFFF; /* 2 bytes */
> -       err = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
> +       err = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
>                         QUERY_ATTR_IDN_EE_CONTROL, 0, 0, &val);
>         if (!err)
>                 hba->ee_ctrl_mask &= ~mask;
> @@ -3435,7 +3472,7 @@ static int ufshcd_enable_ee(struct ufs_hba *hba, u16 mask)
>
>         val = hba->ee_ctrl_mask | mask;
>         val &= 0xFFFF; /* 2 bytes */
> -       err = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
> +       err = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
>                         QUERY_ATTR_IDN_EE_CONTROL, 0, 0, &val);
>         if (!err)
>                 hba->ee_ctrl_mask |= mask;
> @@ -3541,7 +3578,7 @@ static void  ufshcd_force_reset_auto_bkops(struct ufs_hba *hba)
>
>  static inline int ufshcd_get_bkops_status(struct ufs_hba *hba, u32 *status)
>  {
> -       return ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR,
> +       return ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,
>                         QUERY_ATTR_IDN_BKOPS_STATUS, 0, 0, status);
>  }
>
> @@ -3604,7 +3641,7 @@ static int ufshcd_urgent_bkops(struct ufs_hba *hba)
>
>  static inline int ufshcd_get_ee_status(struct ufs_hba *hba, u32 *status)
>  {
> -       return ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR,
> +       return ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,
>                         QUERY_ATTR_IDN_EE_STATUS, 0, 0, status);
>  }
>
> @@ -4360,9 +4397,9 @@ static void ufshcd_init_icc_levels(struct ufs_hba *hba)
>         dev_dbg(hba->dev, "%s: setting icc_level 0x%x",
>                         __func__, hba->init_prefetch_data.icc_level);
>
> -       ret = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
> -                       QUERY_ATTR_IDN_ACTIVE_ICC_LVL, 0, 0,
> -                       &hba->init_prefetch_data.icc_level);
> +       ret = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
> +               QUERY_ATTR_IDN_ACTIVE_ICC_LVL, 0, 0,
> +               &hba->init_prefetch_data.icc_level);
>
>         if (ret)
>                 dev_err(hba->dev,
> --
> 1.8.5.2
>
> --
> QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
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