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Subject: Re: [PATCH RFC 7/7] irqchip: [Example] dummy wired interrupt/MSI
 bridge driver
To: Marc Zyngier <marc.zyngier@arm.com>, Thomas Gleixner <tglx@linutronix.de>,
        Jiang Liu <jiang.liu@linux.intel.com>,
        Jason Cooper <jason@lakedaemon.net>
References: <1444923568-17413-1-git-send-email-marc.zyngier@arm.com>
 <1444923568-17413-8-git-send-email-marc.zyngier@arm.com>
CC: <linux-arm-kernel@lists.infradead.org>, <linux-pci@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
From: "majun (F)" <majun258@huawei.com>
Message-ID: <5639BB10.1090108@huawei.com>
Date: Wed, 4 Nov 2015 16:00:16 +0800
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Hi Marc:

ÔÚ 2015/10/15 23:39, Marc Zyngier дµÀ:
> In order to demonstrate how to put together a wire/MSI bridge,
> add a dummy driver that doesn't do anything at all, except
> for allocating interrupts.
> 
> It comes together with an even more stupid client driver that
> allocates an interrupt and dump the hierarchy of that interrupt.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
[...]
> +
> +static int msichip_domain_alloc(struct irq_domain *domain, unsigned int virq,
> +				   unsigned int nr_irqs, void *arg)
> +{
> +	int i, err;
> +	irq_hw_number_t hwirq;
> +	unsigned int type;
> +	struct irq_fwspec *fwspec = arg;
> +	void *data;
> +
> +	err = msichip_domain_translate(domain, fwspec, &hwirq, &type);
> +	if (err)
> +		return err;
> +

.translate function already called once in  irq_domain_translate(),
I think we don't need call this fucntion one more time here.

> +	err = platform_msi_domain_alloc(domain, virq, nr_irqs);
> +	if (err)
> +		return err;
> +
> +	data = platform_msi_get_host_data(domain);
> +	for (i = 0; i < nr_irqs; i++)
> +		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
> +					      &msichip_chip, data);
> +
> +	return 0;
> +}
> +
[...]
> +
> +static struct platform_driver msichip_driver = {
> +	.driver = {
> +		.name		= "msichip",
> +		.of_match_table	= msichip_of_match,
> +	},
> +	.probe			= msichip_probe,
> +};
> +/* Do not define this as an irqchip */
> +module_platform_driver(msichip_driver);
> +
> +

I think,for a interrupt controller, msichip driver initialization maybe is too late
for some devices which connect to this irqchip if we use module_platform_driver.

So, how about use the arch_initcall to register the msichip driver?

Thanks!
Ma Jun