Re: [Xen-devel] [PATCH 01/10] xen/arm: Implement hip04-d01 platform

[Frediano Ziglio <freddy77@xxxxxxxxx>]

2015-01-13 15:23 GMT+00:00 Ian Campbell <Ian.Campbell@xxxxxxxxxx>:
> On Tue, 2015-01-13 at 15:11 +0000, Frediano Ziglio wrote:
>> 2015-01-13 14:42 GMT+00:00 Ian Campbell <Ian.Campbell@xxxxxxxxxx>:
>> > On Tue, 2015-01-13 at 14:09 +0000, Frediano Ziglio wrote:
>> >> 2015-01-13 11:58 GMT+00:00 Ian Campbell <Ian.Campbell@xxxxxxxxxx>:
>> >> > On Mon, 2014-11-03 at 10:11 +0000, Frediano Ziglio wrote:
>> >> >> Add this new platform to Xen.
>> >> >> This platform require specific code to initialize CPUs.
>> >> >
>> >> > What is the "bootwrapper"? Are you running this on real silicon or on an
>> >> > emulator? Can the platform be made to do PSCI instead?
>> >> >
>> >>
>> >> Very real. It's actually on my desk and I'm not in Matrix :-)
>> >
>> > OK. The choice of bootwrapper as a name is a bit unfortunate, since it
>> > is already used for something else, but oh well.
>> >
>> >> Has no PSCI support. Would be honestly very great. As we (as company)
>> >> write the firmware could be technically doable. There is no plan. This
>> >> piece of software is meant to bring the CPU from Secure mode to
>> >> Unsecure Hypervisor mode before calling kernel/hypervisor code and
>> >> provide supervisor calls.
>> >
>> > Sounds a lot like PSCI to me, except non-standard ;-)
>> >
>> >> >> +    np_fab = dt_find_compatible_node(NULL, NULL, 
>> >> >> "hisilicon,hip04-fabric");
>> >> >
>> >> > Please add a reference to the DT bindings document for these values.
>> >> >
>> >> > linux/Documentation/devicetree/bindings/arm/hisilicon/hisilicon.txt
>> >> > seems related but doesn't talk about most of these fields.
>> >> >
>> >>
>> >> There are documentation in the Linaro kernel, see
>> >> https://git.linaro.org/kernel/linux-linaro-tracking.git/blob/HEAD:/Documentation/devicetree/bindings/arm/hisilicon/hisilicon.txt.
>> >> I hope it will be merged soon.
>> >
>> > Thanks, but this doesn't seem to cover many of the properties used by
>> > the code you are adding, e.g. bootwrapper-{size,magic},
>> > relocation-{entry,size} (in fact it suggests they are part of a
>> > boot-method array).
>> >
>> > I get the feeling these might be legacy/deprecated. Perhaps we could get
>> > away without supporting such things?
>> >
>> > Ian.
>> >
>>
>> No, this is the newest code.
>
> So in this:
>     if ( !dt_property_read_u32(np, "bootwrapper-phys",
>                                &hip04_boot.bootwrapper_phys) ) {
> [...read boot-method array...]
>     }
>     else
>     {
> [... read a bunch of separate properties...]
>     }
>
> Both sides of the if are used by non-legacy code? That's,...
> unfortunate.
>
> I note that only the if case, not the else case, is covered by the
> hisilicon.txt bindings...
>
> Ian.
>

Yes, you are right, there are actually two versions of these settings.
Actually there has been a lot of bouncing between the two versions. We
are also having some discussion on Linaro ML about implementing PSCI.

Frediano

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