Re: [PATCH 07/12] Documentation: dt: imx: add MSCM documentation

[Stefan Agner]

On 2014-12-03 11:52, Arnd Bergmann wrote:
> On Wednesday 03 December 2014 01:12:06 Stefan Agner wrote:
>> +Freescale Vybrid Miscellaneous System Control Module
>> +
>> +The MSCM IP contains Access Control and TrustZone Security hardware,
>> +CPU Configuration registers and Interrupt Router control.
>> +
>> +Required properties:
>> +- compatible : "fsl,vf610-mscm"
>> +- reg : the register range of the MSCM module
>> +
>> +Example:
>> +       mscm: mscm@40001000 {
>> +               compatible = "fsl,vf610-mscm";
>> +               reg = <0x40001000 0x1000>;
>> +       };
> 
> This sounds like one of those generic system controller devices.
> Should this be marked as syscon an accessed through
> syscon_regmap_lookup_by_phandle()?
> 
> If you only eve have one driver touching these registers, that
> won't be necessary of course.
> 

So far, in upstream code the module is not used at all (other than in
U-Boot setting up the interrupt router in a static manner). I think it
is not that "miscellaneous" as it sounds, it mainly controls and
provides information regarding the dual-core stuff, for instance provide
interrupt flags for the CPU-to-CPU interrupts or exports CPU information
(beside the interrupt routing thing). I don't know (yet) if and how we
want export support for that interrupt. We would certainly need it to
support some message based framework (Freescale used it for their
out-of-tree MCC (multi-core communication) stuff, probably we would need
it to implement rpmsg support...).

--
Stefan

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