preferred over interrupt controller drivers open coding their own
reverse mapping scheme.
-irq_domain also implements translation from Device Tree interrupt
-specifiers to hwirq numbers, and can be easily extended to support
-other IRQ topology data sources.
+irq_domain also implements translation from an abstract irq_fwspec
+structure to hwirq numbers (Device Tree and ACPI GSI so far), and can
+be easily extended to support other IRQ topology data sources.
=== irq_domain usage ===
An interrupt controller driver creates and registers an irq_domain by
related resources associated with these interrupts.
3) irq_domain_activate_irq(): activate interrupt controller hardware to
deliver the interrupt.
-3) irq_domain_deactivate_irq(): deactivate interrupt controller hardware
+4) irq_domain_deactivate_irq(): deactivate interrupt controller hardware
to stop delivering the interrupt.
Following changes are needed to support hierarchy irq_domain.