Re: [RFC PATCH v3 06/11] dt-bindings: timer: Update SiFive CLINT bindings for IPI support
From: Rob Herring <robh@kernel.org>
Date: 2021-09-02 00:18:48
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linux-riscv, lkml
On Wed, Sep 1, 2021 at 7:00 AM Anup Patel [off-list ref] wrote:
On Wed, Sep 1, 2021 at 6:59 AM Rob Herring [off-list ref] wrote:quoted
On Mon, Aug 30, 2021 at 09:47:24AM +0530, Anup Patel wrote:quoted
The Linux RISC-V now treats IPIs as regular per-CPU IRQs. This means we have to create a IPI interrupt domain to use CLINT IPI functionality hence requiring a "interrupt-controller" and "#interrupt-cells" DT property in CLINT DT nodes. Impact of this CLINT DT bindings change only affects Linux RISC-V NoMMU kernel and has no effect of existing M-mode runtime firmwares (i.e. OpenSBI).It appears to me you should fix Linux to not need these 2 useless properties. I say useless because #interrupt-cells being 0 is pretty useless.Linux IRQCHIP framework only probes IRQCHIP DT nodes which have "interrupt-controller" DT property.
Right, I believe I wrote that... So what would it look like to fix that? The simplest thing is just drop the check for 'interrupt-controller'. That's just a sanity check and we have other ways to do that now (schemas). Do you need this early? You can always implement your own initcall.
The "interrupt-cells" DT property can be removed because as an interrupt controller SiFive CLINT will only provide IPIs to arch code.
The schema will disagree. Rob