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 27C47C636D3 for ; Sun, 12 Feb 2023 11:48:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229605AbjBLLsY (ORCPT ); Sun, 12 Feb 2023 06:48:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229543AbjBLLsX (ORCPT ); Sun, 12 Feb 2023 06:48:23 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 89775FF24 for ; Sun, 12 Feb 2023 03:48:21 -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 sin.source.kernel.org (Postfix) with ESMTPS id 57C60CE1379 for ; Sun, 12 Feb 2023 11:48:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 54B2BC433EF; Sun, 12 Feb 2023 11:48:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1676202496; bh=jYLsUqjjVBech4qpb9GQd+R/QpNRC0gHmg+FtS6egEk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=LkyglSF+NExOeHX4dPC+gH9EtIdn63jsjQjo+582mrkanFQ89iBuuKBElKb6FugH6 ZkDWI/4YpMc14z5yzEmUfbH7RfD+fTyucBVXLmatLhfz2R+AW3oQ004nxIqtlQ4y0T az+APpJp6hWnuq6BLEMxnIhaBjAvyRMrKeNF4PvHO7Za5B5FzdE4F82XNGV654FqNI Gl/OT4WmmSpNLZ+by9poZo0KXI/UhmEOcLOvTmAKTptF4/dsrSbGws07kgYLrDuHGN hPMPz5eYJCbEMSNjGCD3AyajZnQcoHVX5TASI5uF8USM7REhghfpLK3lmmlidYDGPF 62+MHOOA8E3XA== 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 4.95) (envelope-from ) id 1pRAq6-009idM-2S; Sun, 12 Feb 2023 11:48:14 +0000 Date: Sun, 12 Feb 2023 11:48:13 +0000 Message-ID: <87mt5jksua.wl-maz@kernel.org> From: Marc Zyngier To: Ben Dai Cc: tglx@linutronix.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH] irqchip/gic-v3: Allow 'dma-noncoherent' property for ITS In-Reply-To: <20230212093505.5754-1-ben.dai9703@gmail.com> References: <20230212093505.5754-1-ben.dai9703@gmail.com> 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") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: ben.dai9703@gmail.com, tglx@linutronix.de, linux-kernel@vger.kernel.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 Sun, 12 Feb 2023 09:35:05 +0000, Ben Dai wrote: > > Currently the ITS driver expects the hardware to report whether it is > shareable, but according to the description of the GITS_CBASER register > in the GICv3 architecture specification: > > It is IMPLEMENTATION DEFINED whether this field has a fixed value or > > can be programmed by software. Implementing this field with a fixed > > value is deprecated. > > It means that the hardware may expect the software to correctly configure > the access attributes of the ITS. In order to support those designs where > ITS and CPU are not in a coherent domain, allow 'dma-noncoherent' property > for ITS. No. This is an integration bug, most likely a Rockchip quality design. I have repeatedly explained how to deal with this, and I'm not going to do that again. Please search the list archives. I will not be taking this sort of patch. M. -- Without deviation from the norm, progress is not possible.