How to get node of root interrupt controller

Hi,

I am rewriting the RISCV IMSIC patch in light of the new changes
regarding
the secondary interrupt controllres. The API's and symbols have
changed since
I wrote the initial patch.

IMSIC's parent is intc (for which I want to get node). Earlier, I was
doing
the following:

        iparent =
OF_xref_from_node(ofw_bus_get_node(intr_irq_root_dev));
        cell = IRQ_EXTERNAL_SUPERVISOR;
        irq = ofw_bus_map_intr(dev, iparent, 1, &cell);

There isn't intr_irq_root_dev now. So, how do I get the intc node
during imsic_attach?

Thanks
Regards
Himanshu