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Date: Tue, 18 Nov 2014 22:34:44 +0800
From: "Yun Wu (Abel)" <wuyun.wu@huawei.com>
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To: Thomas Gleixner <tglx@linutronix.de>
CC: Jiang Liu <jiang.liu@linux.intel.com>, LKML <linux-kernel@vger.kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        "Grant Likely" <grant.likely@linaro.org>,
        Marc Zyngier <marc.zyngier@arm.com>,
        Yingjoe Chen <yingjoe.chen@mediatek.com>,
        Yijing Wang <wangyijing@huawei.com>
Subject: Re: [patch 08/16] genirq: Introduce callback irq_chip.irq_write_msi_msg
References: <20141112133941.647950773@linutronix.de> <20141112134120.474411359@linutronix.de> <546B10DF.7020807@huawei.com> <alpine.DEB.2.11.1411181103360.3909@nanos> <546B4A91.6080004@huawei.com> <546B4D0D.9050601@linux.intel.com> <546B4F18.5060705@huawei.com> <alpine.DEB.2.11.1411181518310.3909@nanos>
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On 2014/11/18 22:19, Thomas Gleixner wrote:

> On Tue, 18 Nov 2014, Yun Wu (Abel) wrote:
>> On 2014/11/18 21:43, Jiang Liu wrote:
>>> 	We provide an irq_chip for each type of interrupt controller
>>> instead of devices. For the example mentioned above, if device A
>>> and Group B has different interrupt controllers, we just need to
>>> implement irq_chip_A and irq_chip_B and set irq_chip.irq_write_msi_msg()
>>> to suitable callbacks.
>>> 	The framework already achieves what you you want:)
>>
>> What if device A and group B have the same interrupt controller?
> 
> Well, if write_msg() is different they are hardly the same.
> 

The GICv3 ITS now deals with both PCI and non PCI message interrupts.
We can't require the new devices behave writing message in a same way.
What we can do is to abstract all the endpoints' behavior, and I
provided one abstraction in an earlier reply.

Thanks,
	Abel