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=-15.3 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=unavailable 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 2D44CC11F66 for ; Wed, 14 Jul 2021 08:26:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E9CB613B0 for ; Wed, 14 Jul 2021 08:26:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238483AbhGNI3Q (ORCPT ); Wed, 14 Jul 2021 04:29:16 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:48908 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238489AbhGNI3Q (ORCPT ); Wed, 14 Jul 2021 04:29:16 -0400 Received: from [IPv6:2a02:810a:880:f54:e49e:3ed0:1a77:5623] (unknown [IPv6:2a02:810a:880:f54:e49e:3ed0:1a77:5623]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: dafna) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id C15441F41B8C; Wed, 14 Jul 2021 09:26:22 +0100 (BST) Subject: Re: [PATCH v6 03/11] iommu/mediatek: Add device_link between the consumer and the larb devices To: Yong Wu , Matthias Brugger , Joerg Roedel , Rob Herring , Krzysztof Kozlowski , David Airlie , Mauro Carvalho Chehab Cc: Evan Green , Robin Murphy , Tomasz Figa , Will Deacon , linux-mediatek@lists.infradead.org, srv_heupstream@mediatek.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org, youlin.pei@mediatek.com, Nicolas Boichat , Matthias Kaehlcke , anan.sun@mediatek.com, ming-fan.chen@mediatek.com, yi.kuo@mediatek.com, acourbot@chromium.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, Daniel Vetter , Chun-Kuang Hu , Philipp Zabel , Xia Jiang , Tiffany Lin , Hsin-Yi Wang , Eizan Miyamoto , anthony.huang@mediatek.com References: <20210714025626.5528-1-yong.wu@mediatek.com> <20210714025626.5528-4-yong.wu@mediatek.com> From: Dafna Hirschfeld Message-ID: Date: Wed, 14 Jul 2021 10:26:20 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210714025626.5528-4-yong.wu@mediatek.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On 14.07.21 04:56, Yong Wu wrote: > MediaTek IOMMU-SMI diagram is like below. all the consumer connect with > smi-larb, then connect with smi-common. > > M4U > | > smi-common > | > ------------- > | | ... > | | > larb1 larb2 > | | > vdec venc > > When the consumer works, it should enable the smi-larb's power which > also need enable the smi-common's power firstly. > > Thus, First of all, use the device link connect the consumer and the > smi-larbs. then add device link between the smi-larb and smi-common. > > This patch adds device_link between the consumer and the larbs. > > When device_link_add, I add the flag DL_FLAG_STATELESS to avoid calling > pm_runtime_xx to keep the original status of clocks. It can avoid two > issues: > 1) Display HW show fastlogo abnormally reported in [1]. At the beggining, > all the clocks are enabled before entering kernel, but the clocks for > display HW(always in larb0) will be gated after clk_enable and clk_disable > called from device_link_add(->pm_runtime_resume) and rpm_idle. The clock > operation happened before display driver probe. At that time, the display > HW will be abnormal. > > 2) A deadlock issue reported in [2]. Use DL_FLAG_STATELESS to skip > pm_runtime_xx to avoid the deadlock. > > Corresponding, DL_FLAG_AUTOREMOVE_CONSUMER can't be added, then > device_link_removed should be added explicitly. > > [1] https://lore.kernel.org/linux-mediatek/1564213888.22908.4.camel@mhfsdcap03/ > [2] https://lore.kernel.org/patchwork/patch/1086569/ > > Suggested-by: Tomasz Figa > Signed-off-by: Yong Wu > --- > drivers/iommu/mtk_iommu.c | 22 ++++++++++++++++++++++ > drivers/iommu/mtk_iommu_v1.c | 20 +++++++++++++++++++- > 2 files changed, 41 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > index a02dde094788..ee742900cf4b 100644 > --- a/drivers/iommu/mtk_iommu.c > +++ b/drivers/iommu/mtk_iommu.c > @@ -571,22 +571,44 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev) > { > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > struct mtk_iommu_data *data; > + struct device_link *link; > + struct device *larbdev; > + unsigned int larbid; > > if (!fwspec || fwspec->ops != &mtk_iommu_ops) > return ERR_PTR(-ENODEV); /* Not a iommu client device */ > > data = dev_iommu_priv_get(dev); > > + /* > + * Link the consumer device with the smi-larb device(supplier) > + * The device in each a larb is a independent HW. thus only link > + * one larb here. > + */ > + larbid = MTK_M4U_TO_LARB(fwspec->ids[0]); > + larbdev = data->larb_imu[larbid].dev; > + link = device_link_add(dev, larbdev, > + DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS); > + if (!link) > + dev_err(dev, "Unable to link %s\n", dev_name(larbdev)); shoudn't ERR_PTR be returned in case of failure? Thanks, Dafna > return &data->iommu; > } > > static void mtk_iommu_release_device(struct device *dev) > { > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > + struct mtk_iommu_data *data; > + struct device *larbdev; > + unsigned int larbid; > > if (!fwspec || fwspec->ops != &mtk_iommu_ops) > return; > > + data = dev_iommu_priv_get(dev); > + larbid = MTK_M4U_TO_LARB(fwspec->ids[0]); > + larbdev = data->larb_imu[larbid].dev; > + device_link_remove(dev, larbdev); > + > iommu_fwspec_free(dev); > } > > diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c > index d9365a3d8dc9..d2a7c66b8239 100644 > --- a/drivers/iommu/mtk_iommu_v1.c > +++ b/drivers/iommu/mtk_iommu_v1.c > @@ -424,7 +424,9 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev) > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > struct of_phandle_args iommu_spec; > struct mtk_iommu_data *data; > - int err, idx = 0; > + int err, idx = 0, larbid; > + struct device_link *link; > + struct device *larbdev; > > while (!of_parse_phandle_with_args(dev->of_node, "iommus", > "#iommu-cells", > @@ -445,6 +447,14 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev) > > data = dev_iommu_priv_get(dev); > > + /* Link the consumer device with the smi-larb device(supplier) */ > + larbid = mt2701_m4u_to_larb(fwspec->ids[0]); > + larbdev = data->larb_imu[larbid].dev; > + link = device_link_add(dev, larbdev, > + DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS); > + if (!link) > + dev_err(dev, "Unable to link %s\n", dev_name(larbdev)); > + > return &data->iommu; > } > > @@ -465,10 +475,18 @@ static void mtk_iommu_probe_finalize(struct device *dev) > static void mtk_iommu_release_device(struct device *dev) > { > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > + struct mtk_iommu_data *data; > + struct device *larbdev; > + unsigned int larbid; > > if (!fwspec || fwspec->ops != &mtk_iommu_ops) > return; > > + data = dev_iommu_priv_get(dev); > + larbid = mt2701_m4u_to_larb(fwspec->ids[0]); > + larbdev = data->larb_imu[larbid].dev; > + device_link_remove(dev, larbdev); > + > iommu_fwspec_free(dev); > } > >