Re: [PATCH v2 14/15] scsi: ufs: ufs-exynos: multi-host configuration for exynosauto

Bean Huo
2021-07-29T21:11:02Z

On Wed, 2021-07-28 at 10:39 +0900, Chanho Park wrote:
> > Hi Chanho Park,
> > Thansk for yoru reply.
> > I didn't see your changes about task_tag and IID. Having a look at
> > ufshcd_prepare_utp_scsi_cmd_upiu(), the task tag in the UPIU header
> > is
> > still only task tag. and IID is always 0x00.
> > If you didn't add these changes, your patch is un-readable, and
> > also the
> > driver doesn't have a real usage case.
>
>
> I already replied regarding this in another mail thread and please
> refer below comments. The controller will handle the tag translation.
>
> https://lore.kernel.org/linux-scsi/002901d782c6$937ac0f0$ba7042d0$@samsung.com/
>
>
>
> > Also, you mentioned there is no support/change needed from the UFS
> > device
> > side. But, IMO, if you changed the UPIU header, there are changes
> > needed
> > on the UFS device side in order to use your driver.
>
>
> Please see the figure[1]. Once IID_IN_TASKTAG bit is set, the
> function arbiter will translate the value of UPIU header before
> delivering it to the device.
>
>
>
> [1]:
> https://lore.kernel.org/linux-scsi/20210714071131.101204-1-chanho61.park@samsung.com/
>
>
>
> Best Regards,
>
> Chanho Park

Hi Chanho Park,

thansk for your further reply. I didn't find out your cover-letter in
your patchset before.

IID will be automatically set by HW controller according to the VH_ID
in the tasg_tag byte[7:5]. Before sending this RPMB to UFS device,
doese your controller reset task_tag byte[7:5] to 0x0 or your
controller will keep VH_ID?

one more question, you mentioned para-virtualization, did you use Xen
or KVM?

Kind regards,
Bean