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Date:   Wed, 25 Mar 2020 23:09:10 +0800
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Subject: Re: [PATCH v8 06/11] irqchip: mips-cpu: Convert to simple domain
To:     Thomas Bogendoerfer <tsbogend@alpha.franken.de>
CC:     Marc Zyngier <maz@kernel.org>, linux-mips@vger.kernel.org,
        Huacai Chen <chenhc@lemote.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Jason Cooper <jason@lakedaemon.net>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Allison Randal <allison@lohutok.net>,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org
From:   Jiaxun Yang <jiaxun.yang@flygoat.com>
Message-ID: <777D8DAA-F462-4E8D-9012-C114DE6D56DE@flygoat.com>
Sender: linux-kernel-owner@vger.kernel.org
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=E4=BA=8E 2020=E5=B9=B43=E6=9C=8825=E6=97=A5 GMT+08:00 =E4=B8=8B=E5=8D=881=
1:04:37, Thomas Bogendoerfer <tsbogend@alpha=2Efranken=2Ede> =E5=86=99=E5=
=88=B0:
>On Wed, Mar 25, 2020 at 10:31:21PM +0800, Jiaxun Yang wrote:
>>=20
>>=20
>> =E4=BA=8E 2020=E5=B9=B43=E6=9C=8825=E6=97=A5 GMT+08:00 =E4=B8=8B=E5=8D=
=8810:15:16, Marc Zyngier <maz@kernel=2Eorg> =E5=86=99=E5=88=B0:
>> >On 2020-03-25 13:59, Jiaxun Yang wrote:
>> >
>> >[=2E=2E=2E]
>> >
>> >>>> So probably we can use legacy domain when  MIPS IRQ BASE is in
>the
>> >>>> range of legacy IRQ
>> >>>> and switch to simple domain when it's not in that range?
>> >>>=20
>> >>> No, see below=2E
>> >>>=20
>> >>>> Here in Loongson systems IRQ 0-15 is occupied by I8259 so I did
>> >this
>> >>>> hack=2E
>> >>>=20
>> >>> Well, if you have to consider which Linux IRQ gets assigned,
>> >>> then your platform is definitely not ready for non-legacy
>> >>> irqdomains=2E Just stick to legacy for now until you have removed
>> >>> all the code that knows the hwirq mapping=2E
>> >>=20
>> >> Thanks=2E
>> >>=20
>> >> So I have to allocate irq_desc here in driver manually?
>> >
>> >No, you are probably better off just dropping this patch, as MIPS
>> >doesn't seem to be ready for a wholesale switch to virtual
>interrupts=2E
>>=20
>> It can't work without this patch=2E
>>=20
>> Legacy domain require IRQ number within 0-15=20
>> however it's already occupied by i8259 or "HTPIC" driver=2E
>
>what's the problem here ? AFAIK there could be more than one
>legacy domain, at least that's what at least IP22/SNI in MIPS world=20
>are doing=2E

MIPS_IRQ_BASE must be higher than 15, otherwise it will conflict with i825=
9=2E

However we have only preallocated irq_desc for 0-15=2E
And legacy domain require irq_desc being preallocated=2E

>
>Thomas=2E

--=20
Jiaxun Yang