Messages in this thread | | | Date | Wed, 26 Sep 2018 08:38:53 -0700 (PDT) | Subject | Re: [PATCH v2 3/5] irqchip: RISC-V Local Interrupt Controller Driver | From | Palmer Dabbelt <> |
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On Tue, 25 Sep 2018 22:54:48 PDT (-0700), anup@brainfault.org wrote: > On Mon, Sep 17, 2018 at 7:58 PM Anup Patel <anup@brainfault.org> wrote: >> >> On Mon, Sep 17, 2018 at 7:44 PM Christoph Hellwig <hch@infradead.org> wrote: >> > >> > On Mon, Sep 10, 2018 at 10:08:58PM +0530, Anup Patel wrote: >> > > > They could in theory IFF someone actually get the use case through >> > > > the riscv privileged spec working group. >> > > >> > > Their is no point in having each and every possible local interrupts >> > > defined by RISC-V spec because some of these will be CPU >> > > implementation specific in which case these local interrupts will >> > > be described in platform specific DT passed to Linux. >> > >> > Again, to legally have implementation specific local interrupt types >> > you'll first need to convice the spec to change the status for those >> > fields from reserved to implementation specific. >> >> I agree, this needs to be first clarified in RISC-V spec. May be this is >> a good topic for discussion in any upcoming RISC-V meetup. >> >> Until then anyone can try these patches from riscv_intc_v2 branch of >> https://github.com/avpatel/linux >> > > I released that CLIC is going to be available for both M-mode and S-mode. > Software can choose to use HLIC or CLIC based on it's own preference. > > If we are going to support both HLIC and CLIC in Linux kernel for per-CPU > local interrupts then we should definitely have irqdomain and irqchip for > per-CPU local interrupts. The selection between HLIC and CLIC will be > based on which driver gets probed via DT.
Yes, and note that the CLIC is actually an extension of what is currently available. Thus we could produce a single driver that supports both, with features selected based on a DT entry.
I'm not sure if a native CLIC driver buys us anything in Linux, though, as IIRC there aren't that many CLIC features that will be particularly useful in our space.
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