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Message-ID: <20060808153947.39735.qmail@web25804.mail.ukl.yahoo.com>
Date: Tue, 8 Aug 2006 15:39:47 +0000 (GMT)
From: moreau francis <francis_moreau2000@yahoo.fr>
Reply-To: moreau francis <francis_moreau2000@yahoo.fr>
Subject: Re : [HW_RNG] How to use generic rng in kernel space
To: Michael Buesch <mb@bu3sch.de>
Cc: linux-kernel@vger.kernel.org
In-Reply-To: <200608042308.24421.mb@bu3sch.de>
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Michael Buesch wrote:
> So, if you have a special hwrng on your embedded board and you
> have some special driver in that board, why not interface
> directly from the driver to the hwrng-driver?

This is what I'm currently doing. I was just thinking to use the
new HW-RNG layer and drop common code...

> This is all pretty special case.
> In the hwrng-driver you could still additionally do a
> hrwng_register() to export the functionality to
> userspace, though.
> 

yes I would like to do that but there is a problem: I have no 
access to "rng_mutex" to synchronise hw accesses and I'm
wondering if there's any issue to use a mutex in driver init
code.

> 
> I am not a friend of a direct in-kernel hwrng access interface,
> because it may return crap data by definition. Many (all current)
> RNG devices may fail and return non-random data. If that's happily
> used by some in-kernel user by the interface, we are screwed.
> 
> Why can't you build your random-data consumer as module and load
> it later, when random data is available (and was carefully checked
> by various tests in rngd)?
> 

simply because in this embedded system, there's no module support.

thanks

Francis
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