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

From: Anup Patel
Date: Mon Sep 10 2018 - 12:39:03 EST


On Mon, Sep 10, 2018 at 10:05 PM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> On Mon, Sep 10, 2018 at 10:02:09PM +0530, Anup Patel wrote:
>> You are thinking very much in-context of SiFive CPUs only.
>
> No. I think in terms of the RISC-V spec. I could care less about
> SiFive to be honest.
>
>> Lot of SOC vendors are trying to come-up with their own CPUs
>> and RISC-V spec does not restrict the use of local interrupts.
>
> Yes, it does.
>
>> The mie/mip/sie/sip/uie/uip are all machine word size so on
>> riscv64 we can theoretically have maximum 64 local interrupts.
>
> 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.

Regards,
Anup