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Message-ID: <56C3F4AC.8020807@huawei.com>
Date: Wed, 17 Feb 2016 12:18:52 +0800
From: "majun (F)" <majun258@...wei.com>
To: Marc Zyngier <marc.zyngier@....com>
CC: <Catalin.Marinas@....com>, <linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>, <Will.Deacon@....com>,
<mark.rutland@....com>, <jason@...edaemon.net>,
<tglx@...utronix.de>, <lizefan@...wei.com>, <huxinwei@...wei.com>,
<dingtianhong@...wei.com>, <liguozhu@...ilicon.com>,
<guohanjun@...wei.com>, <zhaojunhua@...ilicon.com>
Subject: Re: [PATCH v2 4/5] irqchip:create irq domain for each mbigen device
在 2016/2/16 16:50, Marc Zyngier 写道:
> On Tue, 16 Feb 2016 14:37:27 +0800
> MaJun <majun258@...wei.com> wrote:
>
>> From: Ma Jun <majun258@...wei.com>
[...]
>> + unsigned int nid;
>> +
>> + nid = get_mbigen_nid(hwirq);
>> +
>> + if (nid < 4)
>> + return (nid * 4) + REG_MBIGEN_VEC_OFFSET;
>> + else
>> + return (nid - 4) * 4 + REG_MBIGEN_EXT_VEC_OFFSET;
>> +}
>> +
>> +static struct irq_chip mbigen_irq_chip = {
>> + .name = "mbigen-v1",
>> +};
>> +
>> +static void mbigen_write_msg(struct msi_desc *desc, struct msi_msg *msg)
>> +{
>> + /* The address of doorbell is encoded in mbigen register by default
>> + * So,we don't need to program the doorbell address at here
>> + * Besides, the event ID is decided by the hardware pin number,
>> + * we can't change it in software.So, we don't need to encode the
>> + * event ID in mbigen register.
>> + */
>
> Really? What if tomorrow I decide to change the EventID allocation
> policy in the ITS driver? Have your HW engineers really baked the
> behaviour of the Linux driver into the device?
>
Yes.
If we really need to support this chip,is there
any possible solution for this problem?
Thanks!
MaJun
> I'm puzzled.
>
> M.
>
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