Re: [PATCH v2 2/3] scsi: ufs: core: Add ufshcd_wb_buf_resize function to enable WB buffer resize

Bart Van Assche
2023-09-08T15:38:18Z

On 9/8/23 03:20, Lu Hongfei wrote:
> diff --git a/drivers/ufs/core/ufshcd-priv.h b/drivers/ufs/core/ufshcd-priv.h
> index f42d99ce5bf1..85caefa421f7 100644
> --- a/drivers/ufs/core/ufshcd-priv.h
> +++ b/drivers/ufs/core/ufshcd-priv.h
> @@ -98,6 +98,7 @@ int ufshcd_exec_raw_upiu_cmd(struct ufs_hba *hba,
> enum query_opcode desc_op);
>
> int ufshcd_wb_toggle(struct ufs_hba *hba, bool enable);
> +int ufshcd_wb_buf_resize(struct ufs_hba *hba, u32 resize_op);
>
> /* Wrapper functions for safely calling variant operations */
> static inline const char *ufshcd_get_var_name(struct ufs_hba *hba)
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> index 93417518c04d..7e4461360cbd 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -6045,6 +6045,27 @@ static bool ufshcd_wb_need_flush(struct ufs_hba *hba)
> return ufshcd_wb_presrv_usrspc_keep_vcc_on(hba, avail_buf);
> }
>
> +int ufshcd_wb_buf_resize(struct ufs_hba *hba, u32 resize_op)
> +{
> + int ret;
> + u8 index;
> +
> + ufshcd_scsi_block_requests(hba);
> + if (ufshcd_wait_for_doorbell_clr(hba, 1 * USEC_PER_SEC))
> + goto out;
> +
> + index = ufshcd_wb_get_query_index(hba);
> + ret = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
> + QUERY_ATTR_IDN_WB_BUF_RESIZE_EN, index, 0, &resize_op);
> + if (ret)
> + dev_err(hba->dev,
> + "%s: Enable WB buf resize operation failed %d\n",
> + __func__, ret);
> +out:
> + ufshcd_scsi_unblock_requests(hba);
> + return ret;
> +}
> +
> static void ufshcd_rpm_dev_flush_recheck_work(struct work_struct *work)
> {
> struct ufs_hba *hba = container_of(to_delayed_work(work),
> diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
> index 7d07b256e906..7dd560dc22c6 100644
> --- a/include/ufs/ufshcd.h
> +++ b/include/ufs/ufshcd.h
> @@ -1381,6 +1381,7 @@ int ufshcd_advanced_rpmb_req_handler(struct ufs_hba *hba, struct utp_upiu_req *r
> struct ufs_ehs *ehs_rsp, int sg_cnt,
> struct scatterlist *sg_list, enum dma_data_direction dir);
> int ufshcd_wb_toggle(struct ufs_hba *hba, bool enable);
> +int ufshcd_wb_buf_resize(struct ufs_hba *hba, u32 resize_op);
> int ufshcd_wb_toggle_buf_flush(struct ufs_hba *hba, bool enable);
> int ufshcd_suspend_prepare(struct device *dev);
> int __ufshcd_suspend_prepare(struct device *dev, bool rpm_ok_for_spm);

My feedback about this patch is as follows:
- If a new function (ufshcd_wb_buf_resize()) is introduced, a caller for
that function should be introduced in the same patch.
- Function declarations should be added either in the private header
file or in the public header file (include/ufs/ufshcd.h) but not in both.
- The name of the ufshcd_wb_buf_resize() function seems misleading to
me. To me that name suggests that this functions resizes the
WriteBooster buffer. That's not what that function does - what it does
it to configure whether or not the UFS device is allowed to resize the
WB buffer.
- Please remove the ufshcd_scsi_block_requests(),
ufshcd_wait_for_doorbell_clr() and ufshcd_scsi_unblock_requests() calls.
I'm not aware of any requirement to pause SCSI command submission while
changing whether or not WB buffer resizing is enabled or disabled.

Thanks,

Bart.