[PATCH v4 1/2] Add the driver of mbigen interrupt controller

On 25/09/15 12:56, majun (F) wrote:

? 2015/9/25 3:30, Marc Zyngier ??:

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On Wed, 23 Sep 2015 15:24:50 +0800
"majun (F)" [off-list ref] wrote:

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+static int mbigen_device_init(struct mbigen_chip *chip,
+                       struct device_node *node)

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+
+core_initcall(mbigen_init);

That's the wrong thing to do. The interrupt controller should be
probed with IRQCHIP_DECLARE(). Yes, this creates a dependency
problem between the MSI layer and the irqchip layer, but that
should be easy (-ish) to solve.

Based on our discusstion about DTS,I will change the code likes below:
IRQCHIP_DECLARE(hisi_mbigen, "hisilicon,mbigen-v2", mbigen_of_init);

Mbigen device is initialized as a interrupt controller.

But I still can't call platform_msi_domain_alloc_irqs()
to apply the msi irqs.

It think this is what you said "dependency problem between
 the MSI layer and the irqchip layer" , am i right ?

Do you have any idea about this problem?

You need to have multiple phases for initializing this beast:
- IRQCHIP_DECLARE() to create the irqchips, allocate the domains and
  the main data structures,
- platform device probing of the top-level device to do some HW probing
  and to kick of_platform_populate on the subnodes,
- Handle the the subnode probing, allocate the MSIs, and finish the
  initialization of the irqchip how that you have all the information.

Ok, I got it. But I still have a question.
According to your suggestions, the initial flow is:

Step1: IRQCHIP_DECLARE() to create the irqchips, allocate the domains and
	the main data structures,
Step2: Parse the device node and apply the irq(named as *device-virq*) within mbigen-device	
	domain (handled by irq core code).
Step3: platform device probing of the top-level device to do some HW probing
	and to kick of_platform_populate on the subnodes,
Step4: Handle the the subnode probing, allocate the MSIs(named as *msi-virq*), and finish the
	initialization of the irqchip how that you have all the information.

My questions is:
	How to connect msi-virq and device-virq ?

In my v4 version, I used the

irq_set_chained_handler(msi-virq, mbigen_handle_cascade_irq);

as msi-virq primary handler function .

Then find  device-virq in mbigen_handle_cascade_irq()
and call device-virq corresponding handler fucntion.

But it seems not a right solution.

So I want try another solution for this problem.

[1] In step2, when the interrupt controller map function is called, using
	irq_set_chip_and_handler(device-irq, &mbigen_irq_chip, handle_fasteoi_irq);
[2] In step4, using
	for_each_msi_entry(desc, &mgn_dev->dev) {
		request_irq( msi-virq, msi_irq_handler, **);
	}

But I am not sure about this solution, please review this and offer me some suggestions.

I don't see what is wrong with keeping it as a chained irq handler.
Actually, you really need it to be a chained handler (because this is
what it is). So using irq_set_chained_handler_and_data() is probably the
right thing to do.

Thanks,

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