On Mon, Mar 26, 2012 at 10:04 AM, KOBAYASHI Yoshitake
<yoshitake.kobayashi@xxxxxxxxxxxxx> wrote:
> Santosh Y wrote:
>>
>> + ucd_cmd_ptr->exp_data_transfer_len =
>> + cpu_to_be32(lrbp->cmd->transfersize);
>> +
>> + memcpy(ucd_cmd_ptr->cdb,
>> + lrbp->cmd->cmnd,
>> + (min_t(unsigned short,
>> + lrbp->cmd->cmd_len,
>> + MAX_CDB_SIZE)));
>
>
> "Exptected Data Transfer Length" field contains a value that
> represents the number of bytes that are required to complete the
> SCSI command request and the number of bytes that the Initiator
> expects to be transferred to/from the Target.
> (JEDEC Standard 220 Table7-7)
> On the other hand, "transfersize" in a scsi_cmnd struct is trimmed
> to the sector size when requested transfer length exceeds it.
> You may derive the actual transfer length from SCSI command itself like
> following.
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index feffe65..e63fecb 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -647,6 +647,34 @@ static void ufshcd_compose_upiu(struct ufshcd_lrb
> *lrbp)
> (min_t(unsigned short,
> lrbp->cmd->cmd_len,
> MAX_CDB_SIZE)));
> +
> + /* Overwrite exptected transfer length by using
> TRANSFER_LENGTH in SCSI commands */
> + switch(ucd_cmd_ptr->cdb[0]) {
> + case READ_6:
> + case WRITE_6:
> + ucd_cmd_ptr->exp_data_transfer_len =
> + cpu_to_be32(lrbp->cmd->transfersize *
> + ucd_cmd_ptr->cdb[4]);
> + break;
> + case READ_10:
> + case WRITE_10:
> + ucd_cmd_ptr->exp_data_transfer_len =
> + cpu_to_be32(lrbp->cmd->transfersize *
> + ((ucd_cmd_ptr->cdb[7] << 8) |
> + ucd_cmd_ptr->cdb[8]));
> + break;
> + case READ_12:
> + case WRITE_12:
Just a minor change, this will be READ_16 and WRITE_16.
> + ucd_cmd_ptr->exp_data_transfer_len =
> + cpu_to_be32(lrbp->cmd->transfersize *
> + ((ucd_cmd_ptr->cdb[10] << 24) |
> + (ucd_cmd_ptr->cdb[11] << 16) |
> + (ucd_cmd_ptr->cdb[12] << 8) |
> + ucd_cmd_ptr->cdb[13]));
> + break;
> + default:
> + break;
> + }
> break;
> case UTP_CMD_TYPE_DEV_MANAGE:
>
> /* For query function implementation */
>
--
~Santosh
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