Re: [PATCH v2 3/5] irqchip: RISC-V Local Interrupt Controller Driver

From: Anup Patel
Date: Wed Sep 26 2018 - 01:55:07 EST

On Mon, Sep 17, 2018 at 7:58 PM Anup Patel <anup@xxxxxxxxxxxxxx> wrote:
> On Mon, Sep 17, 2018 at 7:44 PM Christoph Hellwig <hch@xxxxxxxxxxxxx> 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

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.