Re: [RFC PATCH 0/5] RPMB internal and user-space API + WIP virtio-rpmb frontend

[Alex Bennée]

Avri Altman <avri.altman@xxxxxxx> writes:

> The mmc driver has some hooks to support rpmb access, but access is
> mainly facilitated from user space, e.g. mmc-utils.
>
> The ufs driver has no concept of rpmb access - it is facilitated via
> user space, e.g. ufs-utils and similar.
>
> Both for ufs and mmc, rpmb access is defined in their applicable jedec
> specs. This is the case for few years now - AFAIK No new rpmb-related
> stuff is expected to be introduced in the near future.
>
> What problems, as far as mmc and ufs, are you trying to solve by this
> new subsystem?

Well in my case the addition of virtio-rpmb. As yet another RPMB device
which only supports RPMB transactions and isn't part of a wider block
device. The API dissonance comes into play when looking to implement it
as part of wider block device stacks and then having to do things like
fake 0 length eMMC devices with just an RPMB partition to use existing
tools.

I guess that was the original attraction of having a common kernel
subsystem to interact with RPMB functionality regardless of the
underlying HW. However from the other comments it seems the preference
is just to leave it to user-space and domain specific tools for each
device type.

>
> Thanks,
> Avri


-- 
Alex Bennée