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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 6283FC47404 for ; Fri, 11 Oct 2019 09:16:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 443D52089F for ; Fri, 11 Oct 2019 09:16:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727131AbfJKJQp (ORCPT ); Fri, 11 Oct 2019 05:16:45 -0400 Received: from foss.arm.com ([217.140.110.172]:54162 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726555AbfJKJQo (ORCPT ); Fri, 11 Oct 2019 05:16:44 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2597A337; Fri, 11 Oct 2019 02:16:44 -0700 (PDT) Received: from [192.168.1.123] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6239F3F703; Fri, 11 Oct 2019 02:16:42 -0700 (PDT) Subject: Re: [PATCH 0/2] iommu/arm-smmu: Add an optional "input-address-size" property To: Nicolin Chen , joro@8bytes.org, robh+dt@kernel.org, mark.rutland@arm.com, will@kernel.org Cc: vdumpa@nvidia.com, iommu@lists.linux-foundation.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <20191011034609.13319-1-nicoleotsuka@gmail.com> From: Robin Murphy Message-ID: Date: Fri, 11 Oct 2019 10:16:28 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20191011034609.13319-1-nicoleotsuka@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019-10-11 4:46 am, Nicolin Chen wrote: > This series of patches add an optional DT property to allow an SoC to > specify how many bits being physically connected to its SMMU instance, > depending on the SoC design. This has come up before, and it doesn't work in general because a single SMMU instance can have many master interfaces, with potentially different sizes of address bus wired up to each. It's also a conceptually-wrong approach anyway, since this isn't a property of the SMMU; it's a property of the interconnect(s) upstream of the SMMU. IIRC you were working on Tegra - if so, Thierry already has a plan, see this thread: https://lore.kernel.org/linux-arm-kernel/20190930133510.GA1904140@ulmo/ Robin. > > Nicolin Chen (2): > dt-bindings: arm-smmu: Add an optional "input-address-size" property > iommu/arm-smmu: Read optional "input-address-size" property > > Documentation/devicetree/bindings/iommu/arm,smmu.txt | 7 +++++++ > drivers/iommu/arm-smmu.c | 10 ++++++++-- > 2 files changed, 15 insertions(+), 2 deletions(-) >