RE: [PATCH v3 1/3] rpmb: add Replay Protected Memory Block (RPMB) subsystem

[Winkler, Tomas]

> > > +struct rpmb_frame {
> > > +       u8     stuff[196];
> > > +       u8     key_mac[32];
> > > +       u8     data[256];
> > > +       u8     nonce[16];
> > > +       __be32 write_counter;
> > > +       __be16 addr;
> > > +       __be16 block_count;
> > > +       __be16 result;
> > > +       __be16 req_resp;
> > > +} __packed;
> >
> > I haven't looked at the NVME or the UFS spec in detail. Although, I
> > assume the above frame makes sense for those types of
> interfaces/protocols too?
> The rpmb implementation in ufs, has drifted apart from eMMC. E.g. in
> UFS4.0:
>  -  the frame is different - see struct ufs_arpmb_meta in
> include/uapi/scsi/scsi_bsg_ufs.h,
>  - Additional extended header was added,
>  - the frame size is no longer 512Bytes (256Bytes meta info + 256Bytes data)
> but 4k,
>  - there are 9 rpmb operations instead of 7,
>  - The atomicity requirement of the command sequence was waved, And
> probably more differences that I forgot.
> This is why it is better to designated this as an eMMC-only implementation?

As  I wrote previously the original implementation has already resolved protocol differences
 (NVMe have also different byte ordering) for closed usecase of storing data (not the configuration)  
I believe the whole point here is to let TEE driver to store the data, regardless of the technology. 
 In addition I might be wrong but I don't see much value in eMMC as the UFS and NVMe are currently leading technologies. 
Thanks
Tomas