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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 595CFC433F5 for ; Mon, 2 May 2022 09:45:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Subject:Cc:To:From:Message-ID:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=MZVYuYT4lNV2pVBPzhg0gEX1dZQp8IOHl2tsg+MAlQQ=; b=WQ+t4WRXhy1vDf hDIkFwiSYxucqZoGHZzSCWjRJM9SVpIRx7jsTb8z8TkHpyidGBR8gkfumDv0gaqvStrFeaj5YWln/ 55vk7XWIDqaE/xAwRlyRtrFvw4bTRFQVtJ+JdqihADqx42uVZ5aFulYUIz9iQNSNJHZVrcLhrjdHy ZfAH+vzSqAkz4eEBIAb4Ta1g0fgLvrkFDlG0u7coaRuTu+FBCQaNywSnghBB8Lu/NLRO1ZqxzbMnY inDGduOprq67pDZdiVNvtlASeBHGtWWfks+QuT176I762Rl6nqMdnW+smeDpMLuWRAEEL9quzQ/bV 9ar6Vg8Np6bYc6jmwVNw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nlSbL-000fAu-6q; Mon, 02 May 2022 09:44:19 +0000 Received: from ams.source.kernel.org ([145.40.68.75]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nlSbI-000f9Z-63 for linux-arm-kernel@lists.infradead.org; Mon, 02 May 2022 09:44:17 +0000 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 ams.source.kernel.org (Postfix) with ESMTPS id ECA2DB81022; Mon, 2 May 2022 09:44:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A11E4C385AC; Mon, 2 May 2022 09:44:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1651484652; bh=IfuwAcxovIYrMP9GYmXW3d40rSsRfv/MHnbpuVpMdJA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=YeFnDv9rO0qwQArXD/kS/CB1zZlD5t8/ofeapSkMU+D+a2Bwrp8KNjicxtU8zsGz6 +tnS9YpsyssNsdoCTkMrx6o/FAyqeJfCn76I7pABXUlfiE6m0jOYrGBnwqgxqP+/s0 9ksoZQHJCR3eTA3jbaz/s+MqJCxJaMkH/qRAk/RRwqZjaec12P4S9/JLG4QS4261l+ 5Gsw7lqkugHCYBiLThBDOPGDsmsrZEkwxv3aXsYyLFbiBpFGmmNe6zPz9W7iZF5r5e dZBq7FfuuKBQ3bQ81Pa8m1hXdR8H/15RgVXMD4LTD8eo7McRwu19YN1JejlVBcy8tX nQmTxzAZuwxQw== Received: from sofa.misterjones.org ([185.219.108.64] helo=wait-a-minute.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1nlSbC-008O5g-5G; Mon, 02 May 2022 10:44:10 +0100 Date: Mon, 02 May 2022 10:44:50 +0100 Message-ID: <87levki7zh.wl-maz@kernel.org> From: Marc Zyngier To: "Lad, Prabhakar" Cc: Geert Uytterhoeven , LAK Subject: Re: [QUERY]: Acknowledgment of edge triggered interrupts In-Reply-To: References: 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 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: prabhakar.csengg@gmail.com, geert+renesas@glider.be, linux-arm-kernel@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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220502_024416_411176_DA69E7BA X-CRM114-Status: GOOD ( 20.49 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sat, 30 Apr 2022 19:41:24 +0100, "Lad, Prabhakar" wrote: > > Hi Marc, > > I am currently working on the irq-sifive-plic.c driver. The > irq-sifive-plic.c driver is currently implemented as a chained domain. > On our SoC which uses this block for EDGE interrupts we need to first > acknowledge the interrupt before handling it. Isn't that what the CLAIM register does on the PLIC? AFAICT, this interrupt controller is able to implement the whole flow, irrespective of the trigger mechanism. The spec strongly hints at that, see [1] ("Interrupt gateways"), and the uniform handling that results of it. In a way, this is strikingly similar to what the original ARM GIC does. [1] https://github.com/riscv/riscv-plic-spec/blob/master/riscv-plic.adoc > > I came across a similar situation on a different driver (patch [0]) > but it isn't a chained handler. > > What approach should be taken for chained IRQ domains to handle such cases? I don't think there is anything to change. At least, as long as the Interrupt Gateway is doing its job correctly. How this gateway is configured is unfortunately out of the scope of the architecture, it seems, and I'd expect your HW to have some sort of knobs for the trigger type to be configured. This would be dealt with in a separate stacked driver. Thanks, M. -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel