Messages in this thread | | | Subject | Re: Generic DT binding for IPIs | From | Qais Yousef <> | Date | Thu, 22 Oct 2015 11:44:16 +0100 |
| |
Is there anything more I can do to get more attention about this? I think Marc's suggestion is more generic and future proof, if I send RFC patches for that would this be better?
Thanks, Qais
On 10/14/2015 11:18 AM, Qais Yousef wrote: > Hi, > > This is an attempt to revive a discussion on the right list this time > with all the correct people hopefully on CC. > > While trying to upstream a driver, Thomas and Marc Zyngier pointed out > the need for a generic IPI support in the kernel to allow driver to > reserve and send ones. Hopefully my latest RFC patch will help to > clarify what's being done. > > https://lkml.org/lkml/2015/10/13/227 > > We need a generic DT binding support to accompany that to allow a > driver to reserve an IPI using this new mechanism. > > MarcZ had the following suggestion: > > https://lkml.org/lkml/2015/8/24/628 > > Which in summary is > > mydevice@f0000000 { > interrupt-source = <&intc INT_SPEC 2 &inttarg1 &inttarg1>; > }; > > inttarg1: mydevice@f1000000 { > interrupt-sink = <&intc HWAFFINITY1>; > }; > > inttarg2: cpu@1 { > interrupt-sink = <&intc HWAFFINITY2>; > }; > > > interrupt-sink requests to reserve an IPI that it will receive at > HWAFFINITY cpumask. interrupt-source will not do any reservation. It > will simply connect an IPI reserved by interrupt-sink to the device > that will be responsible for generating that IPI. This description > should allow connecting any 2 devices. > Correct me Marc if I got it wrong please. > > I suggested a simplification by assuming that IPIs will only be > between host OS and a coprocessor which would gives us this form which > I think is easier to deal with > > coprocessor { > interrupt-source = <&intc INT_SPEC COP_HWAFFINITY>; > interrupt-sink = <&intc INT_SPEC CPU_HWAFFINITY>; > } > > > interrupt-source here reserves an IPI to be sent from host OS to > coprocessor at COP_HWAFFINITY. interrupt-sink will reserve an IPI to > be received by host OS at CPU_HWAFFINITY. Less generic but I don't > know how important it is for host OS to setup IPIs between 2 external > coprocessors and whether it should really be doing that. > > What do the DT experts think? Any preference or a better suggestion? > > I tried to keep this short and simple, please let me know if you need > more info or if there's anything that needs more clarification. > > Thanks, > Qais
| |