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=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 52388C3A59F for ; Mon, 26 Aug 2019 13:28:45 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 199322053B for ; Mon, 26 Aug 2019 13:28:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="SxWguzeH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 199322053B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 8DF7315C4; Mon, 26 Aug 2019 13:28:42 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id BB6B915BB for ; Mon, 26 Aug 2019 13:26:17 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 73E5B710 for ; Mon, 26 Aug 2019 13:26:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From :Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=MhfKilNLV8AdxkyYpV9V+99YpggpHbv15IYon9mhMkc=; b=SxWguzeHjibJiQGTh0enGJ7wsj xvlWsmuxilsSrybCT7ApvIPfTJthkTEJChIJ5pY9DHIsQGjUN67v8cKOOKr5a0uXhM5HM4z32vow4 bkkZjRbgFpCc/BYTH1TR2Srt2asiNr4QwjlKzC6thdTiNry7uant3AU9xHnoI8haOOP/qM8zbiqxw 4HlaZ9eaMXY9Je+6oKpIzLdltUVMmtCOJrHiTM/zTsoJ2sL1u6Gn862HOqAy+cr2ZFt3K9eB+DHlR YzntowaXSIiZlnQk9a3lTajwZqbRPQp/EZ6iFMq2aXPq9PasHkqpCJwWzyHeA9WB3ILK9MurfmZqm +7QSFpkQ==; Received: from clnet-p19-102.ikbnet.co.at ([83.175.77.102] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1i2F0h-0007zP-RH; Mon, 26 Aug 2019 13:26:16 +0000 From: Christoph Hellwig To: iommu@lists.linux-foundation.org Subject: [PATCH 6/6] MIPS: document mixing "slightly different CCAs" Date: Mon, 26 Aug 2019 15:25:53 +0200 Message-Id: <20190826132553.4116-7-hch@lst.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190826132553.4116-1-hch@lst.de> References: <20190826132553.4116-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Cc: Shawn Anastasio , Will Deacon , linux-m68k@lists.linux-m68k.org, Guan Xuetao , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Russell King , linux-mips@vger.kernel.org, Paul Burton , Geert Uytterhoeven , Catalin Marinas , James Hogan , Robin Murphy , linux-arm-kernel@lists.infradead.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org Based on an email from Paul Burton, quoting section 4.8 "Cacheability and Coherency Attributes and Access Types" of "MIPS Architecture Volume 1: Introduction to the MIPS32 Architecture" (MD00080, revision 6.01). Signed-off-by: Christoph Hellwig --- arch/mips/Kconfig | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index fc88f68ea1ee..aff1cadeea43 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -1119,6 +1119,13 @@ config DMA_PERDEV_COHERENT config DMA_NONCOHERENT bool + # + # MIPS allows mixing "slightly different" Cacheability and Coherency + # Attribute bits. It is believed that the uncached access through + # KSEG1 and the implementation specific "uncached accelerated" used + # by pgprot_writcombine can be mixed, and the latter sometimes provides + # significant advantages. + # select ARCH_HAS_DMA_WRITE_COMBINE select ARCH_HAS_SYNC_DMA_FOR_DEVICE select ARCH_HAS_UNCACHED_SEGMENT -- 2.20.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu