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Subject: Re: [RFC PATCH 7/7] irqchip/apple-aic: add SMP support to the Apple
 AIC driver.
From:   Mohamed Mediouni <mohamed.mediouni@caramail.com>
In-Reply-To: <71e94b48857cbdd21c5d6bdadf148621@kernel.org>
Date:   Thu, 21 Jan 2021 14:34:24 +0100
Cc:     Arnd Bergmann <arnd@kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Hector Martin <marcan@marcan.st>, linux-kernel@vger.kernel.org,
        Will Deacon <will@kernel.org>,
        Stan Skowronek <stan@corellium.com>
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References: <20210120132717.395873-1-mohamed.mediouni@caramail.com>
 <20210120132717.395873-8-mohamed.mediouni@caramail.com>
 <CAK8P3a1qeVxTxZXpfMe70zpPCSBrTOz23ZTR=PHgw0PP9GUvbw@mail.gmail.com>
 <E77005CF-8B2A-4D17-9330-72ECFD7F3C93@caramail.com>
 <71e94b48857cbdd21c5d6bdadf148621@kernel.org>
To:     Marc Zyngier <maz@kernel.org>
Precedence: bulk


> On 21 Jan 2021, at 14:22, Marc Zyngier <maz@kernel.org> wrote:
>=20
> On 2021-01-21 12:50, Mohamed Mediouni wrote:
>>> On 21 Jan 2021, at 13:44, Arnd Bergmann <arnd@kernel.org> wrote:
>>> On Wed, Jan 20, 2021 at 2:27 PM Mohamed Mediouni
>=20
> [...]
>=20
>>>> +       aic.fast_ipi =3D of_property_read_bool(node, "fast-ipi");
>>> Where is this property documented, and what decides which one to =
use?
>> It=E2=80=99s getting documented in the next patch set.
>> This property is there to enable support for older iPhone processors
>> later on, some of which do not have fast IPI support.
>> On Apple M1, fast-ipi is always on.
>=20
> Then please focus on a single implementation. Additional features can
> always be merged later once something is up and running.
>=20
> Also, there sysregs can be detected by matching the MIDR, so I don't
> think we need a DT property for that.
>=20
> Thanks,
>=20
Because UART access adapters for the new M1 Macs aren=E2=80=99t =
plentiful
at all, I actually use this for development, with iPhones which have=20
much more easy to buy Lightning-to-UART adapters.

(That=E2=80=99s why the old implementation is there too)

Might be worth splitting the new one to a new commit though...

Thank you,
>        M.
> --=20
> Jazz is not dead. It just smells funny...