Re: 3.13-rc3 (commit 7ce93f3) breaks Nokia N900 DT boot

[Tony Lindgren <tony@atomide.com>]

* Pali Rohár <pali.rohar@gmail.com> [131207 05:58]:
> On Saturday 07 December 2013 14:48:20 Sebastian Reichel wrote:
> > On Sat, Dec 07, 2013 at 09:18:32AM +0100, Pali Rohár wrote:
> > > On Saturday 07 December 2013 01:00:27 Sebastian Reichel 
> wrote:
> > > > On Fri, Dec 06, 2013 at 02:27:25PM -0800, Tony Lindgren 
> wrote:
> > > > > * Sebastian Reichel <sre@debian.org> [131206 13:37]:
> > > > > > Nokia N900 DT boot breaks for me using 3.13-rc3. You
> > > > > > can see the relevant kernel output below. Disabling
> > > > > > the AES module in the omap3-n900.dts with status =
> > > > > > "disabled" fixed the boot for me.
> > > > > 
> > > > > OK thanks for letting me know. How about the following
> > > > > patch to fix it?
> > > > 
> > > > That's basically what I did to fix the problem.
> > > > 
> > > > I guess the proper fix would be a runtime check if the
> > > > device can be accessed (if that's possible). AFAIK it is
> > > > possible to use the AES module on the N900 if the
> > > > bootloader is slightly patched.
> > > > 
> > > > Pali, can you elaborate more about this? I've seen, that
> > > > you added a section about this on [0].
> > > > 
> > > > [0] http://elinux.org/N900#M-Shield
> > > > 
> > > > -- Sebastian
> > > 
> > > Yes, if you want to use M-Shield on Nokia N900, you need to
> > > use new version of signed Nokia X-Loader which enable
> > > M-Shield usage outside secure world.
> > > 
> > > Because this updated X-Loader is not official and I think
> > > nobody has it in n900, please disable using these M-Shield
> > > crypto modules on n900.
> > 
> > Is the updated X-Loader available somewhere?
> > 
> 
> It was on mediafire server linked from this thread: 
> http://maemo.org/community/maemo-developers/n900_aes_and_sha1-md5_hw_acceleration_drivers/
>
> Now it is deleted from that server, but I have copy on my HDD.

Hmm OK let's hope there's some working link still around for those.
It seems like we should eventually cover both options, but for
the -rc cycle, we need to just disable those hardware modules in
the .dtsi files.
 
> > > Without patched updated X-Loader kernel will crash.
> > 
> > That's what this thread is about :) It might be better to have
> > a runtime check for the crypto hw's accessability by adding
> > something like this to the driver's probe function:
> > 
> > if (!aes_module_is_accessible()) {
> >     dev_err(&pdev->dev, "Usage of OMAP's AES module is
> > blocked\n"); return -ENODEV;
> > }
> > 
> > That would require, that aes_module_is_accessible() can
> > actually be implemented.
> > 
> 
> You need to ask that question to somebody who has 1) access to 
> secure M-Shield documentation or 2) author who created that M-
> Shield driver if your check is possible...

I think we can check the configuration from the L3 registers.
Looks like we no longer have those defined after purging the
unused defines a while back, but I think the registers for the
configuration are L3_PM_READ_PERMISSION etc registers.
 
> > P.S.: I fixed the mail address of Aaro Koskinen. His nokia
> > mail address doesn't work anymore.

Oops sorry about that, I need to update my address book.

Regards,

Tohy
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