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

Bean Huo
2021-07-26T09:08:20Z

On Wed, 2021-07-14 at 16:11 +0900, Chanho Park wrote:
> UFS controller of ExynosAuto v9 SoC supports multi-host interface for
> I/O
>
> virtualization. In general, we're using para-virtualized driver to
>
> support a block device by several virtual machines. However, it
> should
>
> be relayed by backend driver. Multi-host functionality extends the
> host
>
> controller by providing register interfaces that can be used by each
>
> VM's ufs drivers respectively. By this, we can provide direct access
> to
>
> the UFS device for multiple VMs. It's similar with SR-IOV of PCIe.
>

Hi Chanho Park,
very inteseted in this patch. you mentined SR-IOV. In order to make
your patch work on the UFS, does UFS device side need changes?

or the common current 3.1 UFS can work with this new controller?

>
>
> We divide this M-HCI as PH(Physical Host) and VHs(Virtual Host). The
> PH
>
> supports all UFSHCI functions(all SAPs) same as conventional UFSHCI
> but
>
> the VH only supports data transfer function. Thus, except UTP_CMD_SAP
> and
>
> UTP_TMPSAP, the PH should handle all the physical features.
>
>
>
> This patch provides an initial implementation of PH part. M-HCI can
>
> support up to four interfaces but this patch initially supports only
> 1
>
> PH and 1 VH. For this, we uses TASK_TAG[7:5] field so TASK_TAG[4:0]
> for
>
> 32 doorbel will be supported. After the PH is initiated, this will
> send

I don't understand here. how many doorbell registers you have now?
and doesn VHs have a doorbell register also? and each doorbell register
still supprts 32 tags?

Kind regards
Beab