Re: [rtc-linux] [PATCH 2nd try] RTC/i.MX/DryICE: add recovery routines to the driver

From: Juergen Borleis
Date: Fri Apr 24 2015 - 06:30:08 EST

Hi Alexandre,

On Wednesday 22 April 2015 01:26:15 Alexandre Belloni wrote:
> On 14/04/2015 at 11:11:51 +0200, Juergen Borleis wrote :
> > 2nd try, this time with a cover letter... m(
> >
> > The built-in RTC unit on some i.MX SoCs isn't an RTC only. It is also a
> > tamper monitor unit which can keep some keys. When it does its tamper
> > detection job
> Does it have more functions? I would say that it also holds some keys
> but I don't have a handy Freescale representative to contact ;)

Yes it can hold some keys and will delete them if it detects a security
violation via its tamper detection feature.

> I'm fine getting that unlocking done in the RTC driver but maybe in the
> future, it will be necessary to handle that in an MFD driver when adding
> support for the other functions.

This change set just makes the RTC work again. Observation was, *sometimes* and
*somehow* this unit tends to lock even if no of these tamper detection
features were enabled nor the externals signals (to detect these security
violations) were used.


Pengutronix e.K.                              | Juergen Borleis             |
Industrial Linux Solutions      | |
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