On Mon, 25 Mar 2024 at 09:23, Winkler, Tomas tomas.winkler@intel.com wrote:
+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.
Yes, I also agree. It makes sense to have a generic way to manage RPMB partitions, even if there are some specific parts that must be managed differently based on the underlying technology.
That said, I tend to think that we actually want the UFS and NVMe implementation being included in the $subject series too. To get the complete picture. Otherwise, we may just end up having to redesign a lot of things, if we just start with eMMC.
In addition I might be wrong but I don't see much value in eMMC as the UFS and NVMe are currently leading technologies.
Even if UFS and NVMe have been taking over some of the earlier eMMC product segments, I think it's too soon to declare eMMC dead. :-)
Moreover, we also have older platforms that we want to get supported upstream and allowing them to move away from downstream-hacks, is also a very good reason to add eMMC support.
Thanks Tomas
Kind regards Uffe