Re: [PATCH 0/2] crypto: add new driver for Marvell CESA

[Maxime Ripard]

On Fri, Apr 17, 2015 at 04:19:22PM +0200, Boris Brezillon wrote:
> Hi Gregory,
> 
> On Fri, 17 Apr 2015 15:01:01 +0200
> Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx> wrote:
> 
> > Hi Boris,
> > 
> > On 17/04/2015 10:39, Boris Brezillon wrote:
> > > On Fri, 17 Apr 2015 10:33:56 +0200
> > > Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx> wrote:
> > > 
> > >> Hi Jason,
> > >>
> > >> On Mon, 13 Apr 2015 20:11:46 +0000
> > >> Jason Cooper <jason@xxxxxxxxxxxxxx> wrote:
> > >>
> > >>>>
> > >>>>> I'd appreciate if we'd look into it.  I understand from on-list and
> > >>>>> off-list discussion that the rewrite was unavoidable.  So I'm willing to
> > >>>>> concede that.  Giving people time to migrate from old to new while still
> > >>>>> being able to update for other security fixes seems reasonable.
> > >>>>
> > >>>> Jason, what do you think of the approach above? 
> > >>>
> > >>> I say keep it simple.  We shouldn't use the DT changes to trigger one
> > >>> vice the other.  We need to be able to build both, but only load one at
> > >>> a time.  If that's anything other than simple to do, then we make it a
> > >>> Kconfig binary choice and move on.
> > >>
> > >> Actually I was planning to handle it with a Kconfig dependency rule
> > >> (NEW_DRIVER depends on !OLD_DRIVER and OLD_DRIVER depends
> > >> on !NEW_DRIVER).
> > >> I don't know how to make it a runtime check without adding new
> > >> compatible strings for the kirkwood, dove and orion platforms, and I'm
> > >> sure sure this is a good idea.
> > >   ^ not
> > > 
> > >> Do you have any ideas ?
> > 
> > You use devm_ioremap_resource() in the new driver, so if the old one
> > is already loaded the memory region will be already hold and the new
> > driver will simply fail during the probe. So for this part it is OK.
> 
> I like the idea :-).

Not really, how do you know which device is going to be probed? For
that matter, it's pretty much random, and you have no control over it.

Why not just have a choice option, and select which one you want to
enable?

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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