RE: [PATCH v3 5/6] scsi: ufshpb: Add handing of device reset HPB regions Infos in HPB device mode

Avri Altman
2022-04-25T06:44:08Z

> From: Bean Huo <beanhuo@micron.com>
>
> In UFS HPB Spec JESD220-3A,
>
> "5.8. Active and inactive information upon power cycle
> ...
> When the device is powered off by the host, the device may restore L2P map
> data
> upon power up or build from the host’s HPB READ command. In case device
> powered
> up and lost HPB information, device can signal to the host through HPB Sense
> data,
> by setting HPB Operation as ‘2’ which will inform the host that device reset
> HPB
> information."
>
> Therefore, for HPB device control mode, if the UFS device is reset via the
> RST_N
> pin, the active region information in the device will be reset. If the host side
> receives this notification from the device side, it is recommended to inactivate
> all active regions in the host's HPB cache.
While it makes sense to me, this interpretation of the spec takes extreme action,
Compared to what it is today, and you probably need to get an ack from Daejun.

If we are entering a zone in which each vendor is applying a different logic -
I think you need to facilitate that - maybe in a different patch set.

Thanks,
Avri