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From:   Anup Patel <anup@brainfault.org>
Date:   Wed, 26 Sep 2018 11:24:48 +0530
Message-ID: <CAAhSdy3unGBSS9Xgozwt4so_RBOr1WSugiP-4J49q-GOub2mDQ@mail.gmail.com>
Subject: Re: [PATCH v2 3/5] irqchip: RISC-V Local Interrupt Controller Driver
To:     Palmer Dabbelt <palmer@sifive.com>,
        Christoph Hellwig <hch@infradead.org>,
        Atish Patra <atish.patra@wdc.com>,
        Thomas Gleixner <tglx@linutronix.de>
Cc:     Jason Cooper <jason@lakedaemon.net>,
        Marc Zyngier <marc.zyngier@arm.com>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        "linux-kernel@vger.kernel.org List" <linux-kernel@vger.kernel.org>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        linux-riscv@lists.infradead.org
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On Mon, Sep 17, 2018 at 7:58 PM Anup Patel <anup@brainfault.org> wrote:
>
> On Mon, Sep 17, 2018 at 7:44 PM Christoph Hellwig <hch@infradead.org> wrote:
> >
> > On Mon, Sep 10, 2018 at 10:08:58PM +0530, Anup Patel wrote:
> > > > They could in theory IFF someone actually get the use case through
> > > > the riscv privileged spec working group.
> > >
> > > Their is no point in having each and every possible local interrupts
> > > defined by RISC-V spec because some of these will be CPU
> > > implementation specific in which case these local interrupts will
> > > be described in platform specific DT passed to Linux.
> >
> > Again, to legally have implementation specific local interrupt types
> > you'll first need to convice the spec to change the status for those
> > fields from reserved to implementation specific.
>
> I agree, this needs to be first clarified in RISC-V spec. May be this is
> a good topic for discussion in any upcoming RISC-V meetup.
>
> Until then anyone can try these patches from riscv_intc_v2 branch of
> https://github.com/avpatel/linux
>

I released that CLIC is going to be available for both M-mode and S-mode.
Software can choose to use HLIC or CLIC based on it's own preference.

If we are going to support both HLIC and CLIC in Linux kernel for per-CPU
local interrupts then we should definitely have irqdomain and irqchip for
per-CPU local interrupts. The selection between HLIC and CLIC will be
based on which driver gets probed via DT.

Regards,
Anup