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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 681C9C4332F for ; Tue, 22 Nov 2022 17:28:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233358AbiKVR20 (ORCPT ); Tue, 22 Nov 2022 12:28:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46256 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231842AbiKVR2X (ORCPT ); Tue, 22 Nov 2022 12:28:23 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B63676152 for ; Tue, 22 Nov 2022 09:28:22 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id EA64D617FB for ; Tue, 22 Nov 2022 17:28:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 53FBBC433C1; Tue, 22 Nov 2022 17:28:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1669138101; bh=bPGORzn/O+lk6aHPgo/zL2qYgbZzPpf9Wn0quTNAY3Y=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=knhLOPsIKyVoFTl5kAH4EdE983hWomqK6BYc1AVmzMlyiMs5jtoo45vIdA0aeqNjz 5//NlABsPxh6h4eMGj2709VOZQqBLfECd/gASvC3VJENWGaW6VvCGH+CIbHPE+x/jw URGVd0bwof88pR5PIoq2rcGhdw8bjQTNmA58hWj+lW0qLqeYihzKmmxcdvthRGxhYM cK+r/HR+Obi6P/sUz3q5QKNem9MyFb+gSjwFf3cFIj/A5nCdOshyUs/dOMSgXt6lo2 DdCBSo0cUrGU3p20A2OmSvfOEuT+x+gXDAB26tjqzcgrVYhm0viWpc12mAlOwaJiql hqYdaGxHVC8Nw== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1oxX4E-007vIc-W4; Tue, 22 Nov 2022 17:28:19 +0000 Date: Tue, 22 Nov 2022 17:28:18 +0000 Message-ID: <86o7syoq4t.wl-maz@kernel.org> From: Marc Zyngier To: Icenowy Zheng Cc: Thomas Gleixner , Palmer Dabbelt , Paul Walmsley , Samuel Holland , linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH] irqchip/sifive-plic: drop quirk for two-cell variant In-Reply-To: <20221121042026.419383-1-uwu@icenowy.me> References: <20221121042026.419383-1-uwu@icenowy.me> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: uwu@icenowy.me, tglx@linutronix.de, palmer@dabbelt.com, paul.walmsley@sifive.com, samuel@sholland.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 21 Nov 2022 04:20:26 +0000, Icenowy Zheng wrote: > > As the special handling of edge-triggered interrupts are defined in the > PLIC spec, we can assume it's not a quirk, but a feature of the PLIC > spec; thus making it a quirk and use quirk-based codepath is not so > necessary. It *is* necessary. > > Move to a #interrupt-cells-based practice which will allow both device > trees without interrupt flags and with interrupt flags work for all > compatible strings. No. You're tying together two unrelated concepts: - Edges get dropped in some implementations (and only some). You can argue that the architecture allows it, but I see it is an implementation bug. - The need for expressing additional information in the interrupt specifier is not necessarily related to the above. Other interrupt controllers use extra cells to encode the interrupt affinity, for example. I want these two things to be kept separate. Otherwise, once we get some fancy ACPI support for RISCV (no, please...), we'll have to redo the whole thing... > In addition, this addresses a stable version DT binding violation -- > Linux v5.19 comes with "thead,c900-plic" with #interrupt-cells defined to > be 1 instead of 2, this commit will allow DTs that complies to Linux > v5.19 binding work (although no such DT is devliered to the public now). *That* is what should get fixed. Thanks, M. -- Without deviation from the norm, progress is not possible.