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Date:   Fri, 2 Aug 2019 16:05:37 +0300
From:   Peter De Schrijver <pdeschrijver@nvidia.com>
To:     Dmitry Osipenko <digetx@gmail.com>
CC:     Sowjanya Komatineni <skomatineni@nvidia.com>,
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Subject: Re: [PATCH V6 01/21] irqchip: tegra: Do not disable COP IRQ during
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On Thu, Jul 25, 2019 at 01:59:09PM +0300, Dmitry Osipenko wrote:
> 25.07.2019 13:38, Peter De Schrijver =D0=BF=D0=B8=D1=88=D0=B5=D1=82:
> > On Thu, Jul 25, 2019 at 01:33:48PM +0300, Peter De Schrijver wrote:
> >> On Thu, Jul 25, 2019 at 01:05:13PM +0300, Dmitry Osipenko wrote:
> >>> 25.07.2019 12:55, Peter De Schrijver =D0=BF=D0=B8=D1=88=D0=B5=D1=82:
> >>>> On Mon, Jul 22, 2019 at 12:54:51PM +0300, Dmitry Osipenko wrote:
> >>>>>
> >>>>> All Tegra SoCs support SC7, hence the 'supports_sc7' and the commen=
t
> >>>>> doesn't sound correct to me. Something like 'firmware_sc7' should s=
uit
> >>>>> better here.
> >>>>>
> >>>>>> +			writel_relaxed(~0ul, ictlr + ICTLR_COP_IER_CLR);
> >>>>>
> >>>>> Secondly, I'm also not sure why COP interrupts need to be disabled =
for
> >>>>> pre-T210 at all, since COP is unused. This looks to me like it was
> >>>>> cut-n-pasted from downstream kernel without a good reason and could=
 be
> >>>>> simply removed.
> >>>>
> >>>> I don't think we can rely on the fact that COP is unused. People can
> >>>> write their own code to run on COP.
> >>>
> >>> 1. Not upstream - doesn't matter.
> >>>
> >>
> >> The code is not part of the kernel, so obviously it's not upstream?
> >>
> >>> 2. That's not very good if something unknown is running on COP and th=
en
> >>> kernel suddenly intervenes, don't you think so?
> >>
> >> Unless the code was written with this in mind.
> >>
>=20
> In that case, please see 1. ;)
>=20

In general the kernel should not touch the COP interrupts I think.

> >=20
> > Looking at this again, I don't think we need to enable the IRQ at all.
>=20
> Could you please clarify? The code only saves/restores COP's interrupts
> context across suspend-resume.

The sc7 entry firmware doesn't use interrupts.

Peter.