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

From: Avri Altman
Date: Mon Mar 25 2024 - 09:39:19 EST


> > +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?

Thanks,
Avri