On 2020-10-07 09:53, Marc Zyngier wrote:
On 2020-10-07 09:05, Marc Zyngier wrote:
On 2020-10-06 21:39, Thomas Gleixner wrote:
[...]
This is butt ugly, really. Especially the use case where the tegra
PMC
domain removes itself from the hierarchy from .alloc()
I don't disagree at all. It is both horrible and dangerous.
My preference would have been to split the PMC domain into discrete
domains, each one having having its own depth. But that's incredibly
hard to express in DT, and would break the combination of old/new
DT and kernel.
That said, I don't have a better idea either. Sigh...
A (very minor) improvement would be to turn the trim call in the PMC
driver into
a flag set in the first invalid irq_data structure, and let
__irq_domain_alloc_irqs() do the dirty work.
Still crap, but at least would prevent some form of abuse. Thoughts?
Actually, I wonder whether we can have a more general approach:
A partial hierarchy that doesn't have an irq_data->chip pointer
populated
cannot be valid. So I wonder if the least ugly thing to do is to just
drop
any messing about in the PMC driver, and instead to let
__irq_domain_alloc_irqs()
do the culling, always, by looking for a NULL pointer in
irq_data->chip.
Not any less ugly, but at least doesn't need any driver intervention.
[still talking to myself...]
I implemented that, and it has the advantage of placing the hack in a
single location. It even booted on a garden variety of systems.
I'll post an updated series, and we can compare the various levels
of ugliness.
M.
--
Jazz is not dead. It just smells funny...
