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=-17.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 6102AC432BE for ; Thu, 26 Aug 2021 15:00:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 449D76101C for ; Thu, 26 Aug 2021 15:00:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242874AbhHZPBM (ORCPT ); Thu, 26 Aug 2021 11:01:12 -0400 Received: from foss.arm.com ([217.140.110.172]:48570 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231458AbhHZPBL (ORCPT ); Thu, 26 Aug 2021 11:01:11 -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 0D46F31B; Thu, 26 Aug 2021 08:00:24 -0700 (PDT) Received: from [10.57.15.112] (unknown [10.57.15.112]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 635F03F66F; Thu, 26 Aug 2021 08:00:22 -0700 (PDT) Subject: Re: [PATCH 2/3] drm/etnaviv: fix dma configuration of the virtual device To: Michael Walle , etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Cc: "Lukas F . Hartmann" , Marek Vasut , Lucas Stach , Russell King , Christian Gmeiner , David Airlie , Daniel Vetter References: <20210826121006.685257-1-michael@walle.cc> <20210826121006.685257-3-michael@walle.cc> From: Robin Murphy Message-ID: Date: Thu, 26 Aug 2021 16:00:15 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <20210826121006.685257-3-michael@walle.cc> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-08-26 13:10, Michael Walle wrote: > The DMA configuration of the virtual device is inherited from the first > actual etnaviv device. Unfortunately, this doesn't work with an IOMMU: > > [ 5.191008] Failed to set up IOMMU for device (null); retaining platform DMA ops > > This is because there is no associated iommu_group with the device. The > group is set in iommu_group_add_device() which is eventually called by > device_add() via the platform bus: > device_add() > blocking_notifier_call_chain() > iommu_bus_notifier() > iommu_probe_device() > __iommu_probe_device() > iommu_group_get_for_dev() > iommu_group_add_device() > > Move of_dma_configure() into the probe function, which is called after > device_add(). Normally, the platform code will already call it itself > if .of_node is set. Unfortunately, this isn't the case here. > > Also move the dma mask assignemnts to probe() to keep all DMA related > settings together. I assume the driver must already keep track of the real GPU platform device in order to map registers, request interrupts, etc. correctly - can't it also correctly use that device for DMA API calls and avoid the need for these shenanigans altogether? FYI, IOMMU configuration is really supposed to *only* run at add_device() time as above - the fact that it's currently hooked in to be retriggered by of_dma_configure() on DT platforms actually turns out to lead to various issues within the IOMMU API, and the plan to change that is slowly climbing up my to-do list. Robin. > Signed-off-by: Michael Walle > --- > drivers/gpu/drm/etnaviv/etnaviv_drv.c | 24 +++++++++++++++--------- > 1 file changed, 15 insertions(+), 9 deletions(-) > > diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c b/drivers/gpu/drm/etnaviv/etnaviv_drv.c > index 2509b3e85709..ff6425f6ebad 100644 > --- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c > +++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c > @@ -589,6 +589,7 @@ static int compare_str(struct device *dev, void *data) > static int etnaviv_pdev_probe(struct platform_device *pdev) > { > struct device *dev = &pdev->dev; > + struct device_node *first_node = NULL; > struct component_match *match = NULL; > > if (!dev->platform_data) { > @@ -598,6 +599,9 @@ static int etnaviv_pdev_probe(struct platform_device *pdev) > if (!of_device_is_available(core_node)) > continue; > > + if (!first_node) > + first_node = core_node; > + > drm_of_component_match_add(&pdev->dev, &match, > compare_of, core_node); > } > @@ -609,6 +613,17 @@ static int etnaviv_pdev_probe(struct platform_device *pdev) > component_match_add(dev, &match, compare_str, names[i]); > } > > + pdev->dev.coherent_dma_mask = DMA_BIT_MASK(40); > + pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask; > + > + /* > + * Apply the same DMA configuration to the virtual etnaviv > + * device as the GPU we found. This assumes that all Vivante > + * GPUs in the system share the same DMA constraints. > + */ > + if (first_node) > + of_dma_configure(&pdev->dev, first_node, true); > + > return component_master_add_with_match(dev, &etnaviv_master_ops, match); > } > > @@ -659,15 +674,6 @@ static int __init etnaviv_init(void) > of_node_put(np); > goto unregister_platform_driver; > } > - pdev->dev.coherent_dma_mask = DMA_BIT_MASK(40); > - pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask; > - > - /* > - * Apply the same DMA configuration to the virtual etnaviv > - * device as the GPU we found. This assumes that all Vivante > - * GPUs in the system share the same DMA constraints. > - */ > - of_dma_configure(&pdev->dev, np, true); > > ret = platform_device_add(pdev); > if (ret) { >