[PATCH 2/3] ARM: mxs: crypto: Add Freescale MXS DCP driver
herbert at gondor.apana.org.au
Tue Oct 8 00:36:31 EDT 2013
On Mon, Oct 07, 2013 at 05:48:26PM +0200, Marek Vasut wrote:
> Hello Christoph,
> > Hello Marek,
> > > Marek Vasut <marex at denx.de> hat am 28. September 2013 um 05:35 geschrieben:
> > > [...]
> > >
> > > > > 3) What are those ugly new IOCTLs in the dcp.c driver?
> > > >
> > > > When I firstly posted the driver in the mailinglist, there where one
> > > > person who actually used this interface (it was introduced in
> > > > Freescale's SDK) to use the OTP keys for crypto. As far as I have
> > > > seen, the crypto API does not support such keys (i.e. there seems to
> > > > be no way to tell a driver to use some kind of special keys - which
> > > > are not delivered by the user - via the API).
> > > > Therefore I added this miscdevice and adopted Freescale's interface.
> > >
> > > The keys are programmed into the OTP registers, correct? There is OCOTP d
> > >river
> > >for the MX23/MX28 OTP hardware. This is what should have been used then.
> > > NOTE: This IOCTL interface seems like quite an abusive way to allow userl
> > >and to
> > >access the crypto API in kernel. I understand this is used by some Freesc
> > >ale tool, but won't it be better to fix the Freescale tool instead ?
> > the IOCTL interface is used to AES encrypt a bootstream with the AES key in
> > OCOTP.
> > The idea is that only the DCP can read/access the key once it has been
> > programmed
> > into the OCOTP. If the crypto API has means to tell the DCP to use the key
> > from OCOTP, the tool from Freescale is a minor problem.
> Ah right. I suspect the crypto API services shall not be exported into userland
> at all, yes ? So there has to be some kind of workaround here for this freescale
> tool, which is rather unfortunate.
These ioctls have to go. I should have never let them through in
the first place. Can someone cook up a patch to kill them please?
Email: Herbert Xu <herbert at gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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