[V10 PATCH 2/2] irqchip: gicv2m: Add supports for ARM GICv2m MSI(-X)
suravee.suthikulpanit at amd.com
Wed Nov 5 16:05:32 PST 2014
On 11/4/2014 7:01 AM, Jiang Liu wrote:
> Hi Suravee,
> You may build a two level hierarchy irqdomains. Use the
> utilities in this thread
> http://www.spinics.net/lists/arm-kernel/msg374722.html to build an MSI
> irqdomain to manage MSI controllers
> in PCI devices. And build another irqdomain to manage SPI allocation
> in GICv2.
> That is: MSI irqdomain (program MSI registers) -->
> GIV irqdomain (manage SPIs in GICv2 controller)
I try out your patch from the link above, and I have a couple
1. In the drivers/pci/msi.c: msi_irq_domain_alloc_irqs(), it seems that
the hwirq comes from msi_get_hwirq(dev, msidesc). In GICv2m, hwirq for
MSI is fixed over a specific range. This might require arch-specific
2. In msi_domain_activate, why "if (!irq_data->chip_data)"?
3. In, msi_domain_alloc():
- There should be a way to specify other types of irq handler besides
the "handle_edge_irq". In case of GIC, it needs handle_fasteoi_irq.
- When calling irq_domain_set_hwirq_and_chip(), you are passing "(void
*)(long)i" for the "void *chip_data" parameter. What is this used for,
and where? Shouldn't this be pointing to arch-specific data structure?
- The code is calling irq_domain_alloc_irqs_parent before the loop,
which calls irq_domain_set_hwirq_and_chip() and __irq_set_handler.
Shouldn't the order be switched?
- Overall, it seems that msi_domain_alloc() could be quite different
across architectures. Would it be possible to declare this function as
weak, and allow arch to override (similar to arch_setup_msi_irq)?
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