Messages in this thread | | | Subject | Re: Using irq-crossbar.c | From | Sebastian Frias <> | Date | Mon, 13 Jun 2016 17:15:27 +0200 |
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Hi Marc,
Thanks for your input, please find my comments below.
On 06/11/2016 11:58 AM, Marc Zyngier wrote: >> I think Sebastian is even more baffled by the DT mess >> (sorry, intricacies) than I am. > > This mess is what has saved us from the apocalypse 5 years ago, and > describing a complex system is not easy (what a surprise...). If you > just want to apply recipes without understanding the underlying > constraints, you're in for a lot of pain.
Nobody said we wanted a recipe, but it would help to have examples of each of the configurations supported. Indeed, there is effort in writing the DT bindings and even Documentation/IRQ-domain.txt yet I did not see example drivers for the different configurations. Also, it is difficult to know what is the recommended way, since old APIs are kept for a while.
APIs are usually extended/designed around specific cases, so there must be examples, but they are not easy to find.
> >> The base file he was referring to is: >> >> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/tango4-common.dtsi > > I know which file that is, it is mentioned in the diff. I was merely > trying to point out the glaring mistakes that could be enough for a > interrupt controller hierarchy to be completely non-functional: > > - Your crossbar doesn't have a #interrupt-cells property. How do you > expect the interrupt specifiers to be interpreted?
Thanks for the pointer, actually, after adding "#interrupt-cells = <3>;" I can see the driver getting requests for domain maps and xlates :-)
> - You've changed the default interrupt controller to be your crossbar. > Which means that all the sub-nodes are inheriting it. Have you > checked that this was valid for all of these nodes?
What do you mean with "valid for all these nodes"? All HW irq lines go to the crossbar.
> > And as it has been pointed out before, you seem to be reusing an > existing driver. Do you know for sure that the usage constraints are > similar?
It is not being reused as is, I just thought (incorrectly apparently) that it was a good example for our case.
Best regards,
Sebastian
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