Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Wed, 25 Mar 2020 16:04:37 +0100
From:   Thomas Bogendoerfer <tsbogend@alpha.franken.de>
To:     Jiaxun Yang <jiaxun.yang@flygoat.com>
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
Subject: Re: [PATCH v8 06/11] irqchip: mips-cpu: Convert to simple domain
Message-ID: <20200325150437.GA14217@alpha.franken.de>
References: <20200325035537.156911-1-jiaxun.yang@flygoat.com>
 <20200325035537.156911-7-jiaxun.yang@flygoat.com>
 <20200325123742.GA9911@alpha.franken.de>
 <a69f727d37daac6e20ac08de022245b1@kernel.org>
 <C4892878-8463-448D-897B-5F2C56F5A340@flygoat.com>
 <5eb9ce9ea665ee32da40779f00fc9b37@kernel.org>
 <4BB367D3-B8AD-47B6-ACC2-30752137BC1B@flygoat.com>
 <c4520c4b0b0eaaba5fdbaebfce7b4460@kernel.org>
 <39CF835E-D1D9-4B52-ABDC-BDB17B650936@flygoat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <39CF835E-D1D9-4B52-ABDC-BDB17B650936@flygoat.com>
User-Agent: Mutt/1.5.23 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Mar 25, 2020 at 10:31:21PM +0800, Jiaxun Yang wrote:
> 
> 
> 于 2020年3月25日 GMT+08:00 下午10:15:16, Marc Zyngier <maz@kernel.org> 写到:
> >On 2020-03-25 13:59, Jiaxun Yang wrote:
> >
> >[...]
> >
> >>>> 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?
> >>> 
> >>> No, see below.
> >>> 
> >>>> Here in Loongson systems IRQ 0-15 is occupied by I8259 so I did
> >this
> >>>> hack.
> >>> 
> >>> Well, if you have to consider which Linux IRQ gets assigned,
> >>> then your platform is definitely not ready for non-legacy
> >>> irqdomains. Just stick to legacy for now until you have removed
> >>> all the code that knows the hwirq mapping.
> >> 
> >> Thanks.
> >> 
> >> 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.
> 
> It can't work without this patch.
> 
> Legacy domain require IRQ number within 0-15 
> however it's already occupied by i8259 or "HTPIC" driver.

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 
are doing.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]