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Subject: Re: [PATCH v2 09/10] irqchip: ti-sci-inta: Add support for Interrupt
 Aggregator driver
To:     Santosh Shilimkar <santosh.shilimkar@oracle.com>,
        Grygorii Strashko <grygorii.strashko@ti.com>,
        Lokesh Vutla <lokeshvutla@ti.com>
Cc:     Nishanth Menon <nm@ti.com>,
        Santosh Shilimkar <ssantosh@kernel.org>,
        Rob Herring <robh+dt@kernel.org>, tglx@linutronix.de,
        jason@lakedaemon.net,
        Linux ARM Mailing List <linux-arm-kernel@lists.infradead.org>,
        linux-kernel@vger.kernel.org, Tero Kristo <t-kristo@ti.com>,
        Sekhar Nori <nsekhar@ti.com>,
        Device Tree Mailing List <devicetree@vger.kernel.org>,
        Peter Ujfalusi <peter.ujfalusi@ti.com>
References: <20181018154017.7112-1-lokeshvutla@ti.com>
 <20181018154017.7112-10-lokeshvutla@ti.com>
 <b20127dc-be43-3b00-9960-663738df0069@arm.com>
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 <86va5ssrfm.wl-marc.zyngier@arm.com>
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From:   Marc Zyngier <marc.zyngier@arm.com>
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Organization: ARM Ltd
Message-ID: <e799646e-1fff-f96b-38e8-3d46b0160867@arm.com>
Date:   Wed, 31 Oct 2018 18:42:28 +0000
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On 31/10/18 18:38, Santosh Shilimkar wrote:
> On 10/31/2018 11:21 AM, Marc Zyngier wrote:
>> Hi Grygorii,
>>
> 
> [...]
> 
>>
>> Well, I'm convinced that we do not want a networking driver to be tied
>> to an interrupt architecture, and that the two should be completely
>> independent. But that's my own opinion. I can only see two solutions
>> moving forward:
>>
>> 1) You make the IA a real interrupt controller that exposes real
>> interrupts (one per event), and write your networking driver
>> independently of the underlying interrupt architecture.
>>
>> 2) you make the IA an integral part of your network driver, not exposing
>> anything outside of it, and limiting the interactions with the IR
>> *through the standard IRQ API*. You duplicate this knowledge throughout
>> the other client drivers.
>>
>> I believe that (2) would be a massive design mistake as it locks the
>> driver to a single of the HW (and potentially a single revision of the
>> firmware) while (1) gives you the required level of flexibility by
>> hiding the whole event "concept" at a single location.
>>
>> Yes, (1) makes you rewrite your existing, out of tree drivers. Oh well...
>>
> My preference is also not tie the network driver with IA. BTW, this is
> very standard functionality with other network drivers too. And this
> is handled using MSI-X.
> 
> So strong NO for 1) from me as well.

Err. Are you opposing to (1) or (2)? From the above, I cannot really
tell... ;-)

	M.
-- 
Jazz is not dead. It just smells funny...