On Fri, Nov 1, 2019 at 3:30 PM Stefano Stabellini stefano.stabellini@xilinx.com wrote:
On Fri, 1 Nov 2019, Rob Herring wrote:
Action items:
- All: if you can think of simple solution to interrupt-map info duplication, let Stefano know & he will try to add to the example.
- Stefano: Remove ranges from amba_rpu
- Stefano: In next couple weeks, look at GPIO controller extensions & write in detail & send to list so we can discuss.
I am trying to look for the interrupt-related GPIO extensions, and the only one I could find is: socionext,interrupt-ranges from Documentation/devicetree/bindings/gpio/gpio-uniphier.txt:
- socionext,interrupt-ranges: Specifies an interrupt number mapping between this GPIO controller and its interrupt parent, in the form of arbitrary number of <child-interrupt-base parent-interrupt-base length> triplets.
No, there's numerous examples that *should* have used interrupt-map, but invented their own thing.
which is very similar to what we need here, but it looks like a socionext specific property while I seem to recall that Rob said that it was made "standard".
Rob, is this the property you had in mind? Or is there another one?
No. It's '*-map-pass-thru' and in the DT spec. Here's the commit adding it[1]. The motivation for this was GPIO, but the spec was written generically.
Rob
[1] https://github.com/devicetree-org/devicetree-specification/commit/32c96cd64d...
Thank you, that was very helpful! So if I read it right, it would turn it into this at the interrupt-multiplexer node:
#interrupt-cells = <3>; /* copy all attributes from children to parents */ interrupt-map-pass-thru = <0xffffffff 0xffffffff 0xffffffff>; /* mask all childres bits to always match the first 0x0 entries */ interrupt-map-mask = <0x0 0x0 0x0>; /* child address cells, child interrupt cells, parent, parent interrupt cells */ interrupt-map = <0x0 0x0 0x0 &gic_a72 0x0 0x0 0x0>, <0x0 0x0 0x0 &gic_r5 0x0 0x0 0x0>;The zero interrupt-map-mask would make sure that any children interrupts would match the two zero interrupt-map entries. The fully set interrupt-map-pass-thru would make sure that any children interrupts numbers and flags would be copied over to the parents.
I believe that's right. Of course, there's no kernel support for interrupt-map-pass-thru (there is for GPIO), and it in no way solves the problem of which entry to select. A simple way to solve this is to look for 'interrupt-parent' in the /cpus node when not found in the root node. The OS would just have to know which /cpus node to look in. That wouldn't work for existing OSs, but it's not major changes to dts files or OSs. For your case, interrupt-map is not even needed. For the complex case, you'd split interrupt-map for each GIC into each /cpus node.
Rob