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Message-ID: <CAMP5Xgfo-4h3DYki0VWhQFjBtAE9=f9dqCZQV8VDvfJ3Rc_2UQ@mail.gmail.com>
Date: Wed, 1 Jun 2016 16:21:01 -0700
From: Arve Hjønnevåg <arve@...roid.com>
To: Tomas Winkler <tomas.winkler@...el.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Ulf Hansson <ulf.hansson@...aro.org>,
Adrian Hunter <adrian.hunter@...el.com>,
James Bottomley <James.Bottomley@...senpartnership.com>,
"Martin K. Petersen" <martin.petersen@...cle.com>,
Vinayak Holikatti <vinholikatti@...il.com>,
Andy Lutomirski <luto@...nel.org>,
Michael Ryleev <gmar@...gle.com>,
Joao Pinto <Joao.Pinto@...opsys.com>,
Christoph Hellwig <hch@....de>,
Yaniv Gardi <ygardi@...eaurora.org>,
LKML <linux-kernel@...r.kernel.org>, linux-mmc@...r.kernel.org,
linux-scsi@...r.kernel.org
Subject: Re: [PATCH v4 0/8] Replay Protected Memory Block (RPMB) subsystem
On Wed, Jun 1, 2016 at 2:41 PM, Tomas Winkler <tomas.winkler@...el.com> wrote:
> Few storage technology such is EMMC, UFS, and NVMe support RPMB
> hardware partition with common protocol and frame layout.
> The RPMB partition cannot be accessed via standard block layer, but
> by a set of specific commands: WRITE, READ, GET_WRITE_COUNTER, and
> PROGRAM_KEY.
>...
If the same protocol is used by all these standards, why not export it
directly (including the RESULT_READ command or not even knowing the
command types)? While I would prefer an rpmb specific interface over
the existing raw mmc command interface, all I need is an rpmb
operation that lets me send and receive buffers without interruption.
You can find our exiting user-space code here at
https://android.googlesource.com/platform/system/core/+/master/trusty/storage/proxy/rpmb.c.
If you use an interface more similar to this, I think your emmc and
ufs specific code would be simpler. Also, if you don't need the
in-kernel interface, the kernel would not need to know the details of
the rpmb protocol at all.
I have not tested your code, but it looks like we would have to modify
the storage proxy to interpret the data it currently passes through
and remove all RESULT_READ packets.
--
Arve Hjønnevåg
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