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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,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 5BD56C46464 for ; Tue, 14 Aug 2018 11:40:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ECFEE21741 for ; Tue, 14 Aug 2018 11:40:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ECFEE21741 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com 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 S1732304AbeHNO0v (ORCPT ); Tue, 14 Aug 2018 10:26:51 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:42220 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730099AbeHNO0v (ORCPT ); Tue, 14 Aug 2018 10:26:51 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B56ED7A9; Tue, 14 Aug 2018 04:40:03 -0700 (PDT) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 85D413F73C; Tue, 14 Aug 2018 04:40:03 -0700 (PDT) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id 232EE1AE015E; Tue, 14 Aug 2018 12:40:09 +0100 (BST) Date: Tue, 14 Aug 2018 12:40:09 +0100 From: Will Deacon To: Vivek Gautam Cc: joro@8bytes.org, andy.gross@linaro.org, robin.murphy@arm.com, bjorn.andersson@linaro.org, iommu@lists.linux-foundation.org, mark.rutland@arm.com, david.brown@linaro.org, tfiga@chromium.org, swboyd@chromium.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, robdclark@gmail.com Subject: Re: [PATCH 0/5] Qcom smmu-500 TLB invalidation errata for sdm845 Message-ID: <20180814114009.GF28664@arm.com> References: <20180814105528.20592-1-vivek.gautam@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180814105528.20592-1-vivek.gautam@codeaurora.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Vivek, On Tue, Aug 14, 2018 at 04:25:23PM +0530, Vivek Gautam wrote: > Qcom's implementation of arm,mmu-500 on sdm845 has a functional/performance > errata [1] because of which the TCU cache look ups are stalled during > invalidation cycle. This is mitigated by serializing all the invalidation > requests coming to the smmu. How does this implementation differ from the one supported by qcom_iommu.c? I notice you're adding firmware hooks here, which we avoided by having the extra driver. Please help me understand which devices exist, how they differ, and which drivers are intended to support them! Also -- you didn't CC all the maintainers for the firmware bits, so adding Andy here for that, and Rob for the previous question. Thanks, Will