Re: [RFC PATCH v0.2] PCI: Add support for tango PCIe host bridge

From: Marc Zyngier
Date: Wed Apr 12 2017 - 04:08:41 EST


On 11/04/17 18:52, Mason wrote:
> On 11/04/2017 18:43, Marc Zyngier wrote:
>
>> On 11/04/17 17:26, Mason wrote:
>>
>>> Is there a function to map virq to the hwirq in any domain?
>>
>> Be more precise. If you want the hwirq associated with the view of a
>> virq in a given domain, that's the hwirq field in the corresponding
>> irq_data structure. Or are you after something else?
>
> I registered an unmask method for my irq_chip.
> (IIUC, I'm supposed to unmask a specific MSI in this callback.)
>
> # cat /proc/interrupts
> CPU0 CPU1
> 30: 0 0 MSIfoo 0 Edge aerdrv
> 34: 0 0 MSIfoo 524288 Edge xhci_hcd
> 35: 0 0 MSIfoo 524289 Edge xhci_hcd
> 36: 0 0 MSIfoo 524290 Edge xhci_hcd
>
>
> void foo_unmask(struct irq_data *data)
> {
> int xx,yy;
> struct irq_domain *dom = data->domain;
> printk("%s: irq_data=%p irq=%u hwirq=%lu chip=%p dom=%p pdata=%p data=%p\n",
> __func__, data, data->irq, data->hwirq, data->chip, data->domain,
> data->parent_data, data->chip_data);
> printk("%s ops=%p data=%p parent=%p\n\n",
> dom->name, dom->ops, dom->host_data, dom->parent);
> printk("pcie=%p\n", dom->parent->host_data);
> //dump_stack();
> pci_msi_unmask_irq(data);
> struct tango_pcie *pcie = data->domain->parent->host_data;
> printk("\n%s: pcie=%p irq=%u hwirq=%lu\n\n",
> __func__, pcie, data->irq, data->hwirq);
> xx = irq_find_mapping(pcie->irq_domain, data->hwirq);
> yy = irq_find_mapping(pcie->msi_domain, data->hwirq);

Do you realize that hwirq is *per domain*, and only makes sense to *one*
irqchip? What you've written here doesn't make any sense.

> printk("xx=%d yy=%d\n", xx, yy);
> }
>
> so data->irq is the virq (30, 34, 35, 36)
> and data->hwirq is the domain hwirq (0, 524288, 524289, 524290)
>
> Is there a way to map hwirq 524288 to MSI 0, hwirq 524289 to MSI 1, etc?

Why would you need to do such a thing?
- In MSI domain: IRQ34 -> hwirq 524288
- In foo domain: IRQ34 -> hwirq [whatever your driver has allocated]

The data is already there, at your fingertips. Just deal with with your
"foo" irqchip.

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