It appears that some HW is ugly enough that not all the interrupts
connected to a particular interrupt controller end up with the same
hierarchy depth (some of them are terminated early). This leaves
the irqchip hacker with only two choices, both equally bad:
- create discrete domain chains, one for each "hierarchy depth",
which is very hard to maintain
- create fake hierarchy levels for the shallow paths, leading
to all kind of problems (what are the safe hwirq values for these
fake levels?)
Implement the ability to cut short a single interrupt hierarchy
from a level marked as being disconnected by using the new
irq_domain_disconnect_hierarchy() helper.
The irqdomain allocation code will then perform the trimming
Signed-off-by: Marc Zyngier <maz@kernel.org>
5556797662