From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51ABBC67790 for ; Fri, 27 Jul 2018 14:40:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0B034208AF for ; Fri, 27 Jul 2018 14:40:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0B034208AF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732846AbeG0QCZ (ORCPT ); Fri, 27 Jul 2018 12:02:25 -0400 Received: from verein.lst.de ([213.95.11.211]:41659 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730458AbeG0QCZ (ORCPT ); Fri, 27 Jul 2018 12:02:25 -0400 Received: by newverein.lst.de (Postfix, from userid 2407) id 47D0568D60; Fri, 27 Jul 2018 16:44:05 +0200 (CEST) Date: Fri, 27 Jul 2018 16:44:05 +0200 From: Christoph Hellwig To: Atish Patra Cc: Christoph Hellwig , "tglx@linutronix.de" , "palmer@sifive.com" , "jason@lakedaemon.net" , "marc.zyngier@arm.com" , "robh+dt@kernel.org" , "mark.rutland@arm.com" , "anup@brainfault.org" , "devicetree@vger.kernel.org" , "aou@eecs.berkeley.edu" , "linux-kernel@vger.kernel.org" , "linux-riscv@lists.infradead.org" , "shorne@gmail.com" Subject: Re: RFC: simplified RISC-V interrupt and clocksource handling Message-ID: <20180727144405.GB29626@lst.de> References: <20180726143723.16585-1-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 26, 2018 at 04:38:43PM -0700, Atish Patra wrote: > 1. As per my understanding, timer interrupt now can't be registered as a > Linux IRQ now. Thus, /proc/interrupts will not be automatically populated > for timer interrupt stats. Am I wrong in my assumption? Yes, with this code the timer interrupt does not show up in /proc/interrupts. I wonder if that is an issue and if there is any precedence for it? > 2. The future version of local interrupt controller known as Core Level > Interrupt Controller aka CLIC. Do we have to change the current design > again for CLIC in future? > > Here are the docs: > https://github.com/sifive/clic-spec/blob/master/clic.adoc This doesn't really look like 'the future' version but a proposal for something more like low end realtime microcontrollers ala ARM Cortex M*. At least the priorities don't really make much sense for a general purpose SOC. Either way the existing architectural scause/sie interrupt handling will remain but can be opted out, but if we really want to support the CLIC it would have to grow a new irqchip driver, and the PLIC driver would require a few dozend new lines of glue code to chain underneath it.