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_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 AC31DC49ED9 for ; Tue, 10 Sep 2019 16:52:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8B3722082C for ; Tue, 10 Sep 2019 16:52:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2436687AbfIJQwG (ORCPT ); Tue, 10 Sep 2019 12:52:06 -0400 Received: from foss.arm.com ([217.140.110.172]:38308 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2436473AbfIJQwF (ORCPT ); Tue, 10 Sep 2019 12:52:05 -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 F13301000; Tue, 10 Sep 2019 09:52:04 -0700 (PDT) Received: from [10.1.197.57] (e110467-lin.cambridge.arm.com [10.1.197.57]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B2D733F71F; Tue, 10 Sep 2019 09:52:00 -0700 (PDT) Subject: Re: [PATCH v2 1/2] iommu: add support for drivers that manage iommu explicitly To: Rob Clark , Joerg Roedel Cc: "list@263.net:IOMMU DRIVERS" , Joerg Roedel , iommu@lists.linux-foundation.org, dri-devel , linux-arm-msm , Will Deacon , Rob Clark , Greg Kroah-Hartman , "Rafael J. Wysocki" , Andrew Morton , Suzuki K Poulose , Rasmus Villemoes , Heikki Krogerus , Bartosz Golaszewski , Sudeep Holla , Joe Perches , Arnd Bergmann , open list References: <20190906214409.26677-1-robdclark@gmail.com> <20190906214409.26677-2-robdclark@gmail.com> <20190910081415.GB3247@8bytes.org> From: Robin Murphy Message-ID: <4b5b59bb-39a4-0757-e2bb-0961cfc7e4c1@arm.com> Date: Tue, 10 Sep 2019 17:51:57 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 10/09/2019 16:34, Rob Clark wrote: > On Tue, Sep 10, 2019 at 1:14 AM Joerg Roedel wrote: >> >> On Fri, Sep 06, 2019 at 02:44:01PM -0700, Rob Clark wrote: >>> @@ -674,7 +674,7 @@ int iommu_group_add_device(struct iommu_group *group, struct device *dev) >>> >>> mutex_lock(&group->mutex); >>> list_add_tail(&device->list, &group->devices); >>> - if (group->domain) >>> + if (group->domain && !(dev->driver && dev->driver->driver_manages_iommu)) >> >> Hmm, this code usually runs at enumeration time when no driver is >> attached to the device. Actually it would be pretty dangerous when this >> code runs while a driver is attached to the device. How does that change >> make things work for you? >> > > I was seeing this get called via the path driver_probe_device() -> > platform_dma_configure() -> of_dma_configure() -> of_iommu_configure() > -> iommu_probe_device() -> ... > > The only cases I was seeing where dev->driver is NULL where a few > places that drivers call of_dma_configure() on their own sub-devices. > But maybe there are some other paths that I did not notice? For the of_iommu flow, it very much depends on your DT layout and driver probe order as to whether you catch the "proper" call from iommu_bus_notifier()/iommu_bus_init() or the late "replay" from of_iommu_configure(). I wouldn't make any assumptions of consistency. Robin.