Re: [PATCH v1 3/3] scsi: ufs: Utilize Transfer Request List Completion Notification Register

[Stanley Chu]

Hi Can,

On Mon, 2021-05-24 at 01:36 -0700, Can Guo wrote:
> By reading the UTP Transfer Request List Completion Notification Register,
> which is added in UFSHCI Ver 3.0, SW can easily get the compeleted transfer
> requests. Thus, SW can get rid of host lock, which is used to synchronize
> the tr_doorbell and outstanding_reqs, on transfer requests dispatch and
> completion paths. This can further benefit random read/write performance.
> 
> Cc: Stanley Chu <stanley.chu@xxxxxxxxxxxx>
> Co-developed-by: Asutosh Das <asutoshd@xxxxxxxxxxxxxx>
> Signed-off-by: Asutosh Das <asutoshd@xxxxxxxxxxxxxx>
> Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>

Reviewed-by: Stanley Chu <stanley.chu@xxxxxxxxxxxx>


> +++ b/drivers/scsi/ufs/ufshci.h
> @@ -39,6 +39,7 @@ enum {
>  	REG_UTP_TRANSFER_REQ_DOOR_BELL		= 0x58,
>  	REG_UTP_TRANSFER_REQ_LIST_CLEAR		= 0x5C,
>  	REG_UTP_TRANSFER_REQ_LIST_RUN_STOP	= 0x60,
> +	REG_UTP_TRANSFER_REQ_LIST_COMPL		= 0x64,
>  	REG_UTP_TASK_REQ_LIST_BASE_L		= 0x70,
>  	REG_UTP_TASK_REQ_LIST_BASE_H		= 0x74,
>  	REG_UTP_TASK_REQ_DOOR_BELL		= 0x78,