Re: [PATCH v2 3/3] scsi: ufs: core: Add sysfs attributes to control WB buffer resize function

[Bart Van Assche]

> +What:		/sys/bus/platform/drivers/ufshcd/*/enable_wb_buf_resize
> +What:		/sys/bus/platform/devices/*.ufs/enable_wb_buf_resize
> +Date:		Sept 2023
> +Contact:	Lu Hongfei <luhongfei@xxxxxxxx>
> +Description:
> +		The host can decrease or increase the WriteBooster Buffer size by setting
> +		this file.
> +
> +		======  ======================================
> +		   00h  Idle (There is no resize operation)
> +		   01h  Decrease WriteBooster Buffer Size
> +		   02h  Increase WriteBooster Buffer Size
> +		Others  Reserved
> +		======  ======================================
> +
> +		The file is write only.

The name "enable_wb_buf_resize" seems misleading to me. 
"wb_buf_resize_control" is probably a better name for this attribute 
since this attribute can be used to increase and decrease the WB buffer 
size.

> +	if (hba->dev_info.wspecversion < 0x410 ||
> +	    !hba->dev_info.b_presrv_uspc_en) {
> +		dev_err(dev, "The WB buf resize is not allowed!\n");
> +		return -EINVAL;
> +	}

Please leave out the version number check. There probably will be UFS 
4.0 devices that will implement this feature.

Thanks,

Bart.