[PATCH v5 1/3] initialize each mbigen device node as a interrupt controller.

Thomas Gleixner
2015-10-13T06:55:35Z

Majun,

On Tue, 13 Oct 2015, majun (F) wrote:
> ? 2015/10/12 0:45, Thomas Gleixner ??:
> > So now in the mbigen case this looks like this:
> >
> > [MSI-BUS] ----- [MBIGEN]<-------------------[Device interrupt]
> >
> > Again, you have a 'wire' from the device to the MSI unit (MBIGEN) and
> > we do not care about that 'wire' either. What we care about is how we
> > find the MSI (mbigen) configuration registers for a particular
> > device. So we need a DT/ACPI entry which describes those configuration
> > registers and whatever supplementary information is required. That
> > will make the mbigen driver extremly simple.
> >
>
> According to your suggestions, I tried to make the hardware structure likes below:
>
> device(8250 uart) -> mbigne -> ITS-pMSI --> ITS --> GIC

I'm not sure whether mbigen should be connected to ITS-pMSI (I assume
you mean ITS-PCI-MSI).

mbigen is a seperate MSI domain, so it should connect to ITS, but I
leave that to Marc.

> And 8250 uart dts node is:
>
> 8250_uart {
> compatible = "xxx";
> msi-parent = < &mbigen>;
> config_addr = <xxxxx> ; /* configuration register */
> interrupts = <x>;
> interrupt-parent = ?
> }
>
> My question is what's the interrupt-parent should be?

There is no interrupt parent for 8250_uart. Why would you want that?
I'm really not a DT expert, but I think you want something like this:

8250_uart {
compatible = "xxx";
msi-parent = < &mbigen_node5>;
interrupt-map = <&mbigen5 0>;
};

and then have

mbigen_node5 {
...
reg = <....>;
};

So the other devices which are connected to mbigen_node5 have the same
msi-parent. But then again, please discuss that with Marc and the DT
wizards.

Thanks,

tglx