linux-kernel - RE: [tpmdd-devel] [PATCH] Add "shutdown" to "struct class".

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Date:   Mon, 15 May 2017 16:17:36 +0000
From:   "Winkler, Tomas" <tomas.winkler@...el.com>
To:     Jason Gunthorpe <jgunthorpe@...idianresearch.com>
CC:     Josh Zimmerman <joshz@...gle.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "tpmdd-devel@...ts.sourceforge.net" 
        <tpmdd-devel@...ts.sourceforge.net>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>
Subject: RE: [tpmdd-devel] [PATCH] Add "shutdown" to "struct class".

> 
> On Sat, May 13, 2017 at 12:43:11PM +0000, Winkler, Tomas wrote:
> > > The TPM class has some common shutdown code that must be executed
> > > for all drivers. This adds some needed functionality for that
> >
> > The issue with this is, that on some platforms the only storage can be
> > eMMC and TPM is using it,. It has to be ensured that the storage
> > device won't go down before TPM2_shutdown is called.  And there is no
> > direct device hierarchy to ensure an orderly shutdown.
> 
> Something will have to use the new device links stuff to define that
> dependency, but that seems unrelated to this patch?


Yep, it's not directly related to this specific patch, this is more relevant particularly to TPM2_shutdown. 

> Can the kernel really shut down the eMMC while the hidden platform stuff is
> still possibly using it? Goofy..

eMMC is single headed, so yes that can happen.

Tomas