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=-15.2 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 CEC36C56202 for ; Thu, 26 Nov 2020 16:44:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A3D9D221E2 for ; Thu, 26 Nov 2020 16:44:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403842AbgKZQoA (ORCPT ); Thu, 26 Nov 2020 11:44:00 -0500 Received: from foss.arm.com ([217.140.110.172]:39520 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730181AbgKZQoA (ORCPT ); Thu, 26 Nov 2020 11:44:00 -0500 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 8C5F631B; Thu, 26 Nov 2020 08:43:59 -0800 (PST) Received: from [10.57.59.159] (unknown [10.57.59.159]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 571FC3F23F; Thu, 26 Nov 2020 08:43:56 -0800 (PST) Subject: Re: [PATCH v4 12/24] iommu/mediatek: Move hw_init into attach_device To: Yong Wu , Joerg Roedel , Matthias Brugger , Rob Herring , Will Deacon Cc: youlin.pei@mediatek.com, devicetree@vger.kernel.org, Nicolas Boichat , srv_heupstream@mediatek.com, chao.hao@mediatek.com, kernel-team@android.com, linux-kernel@vger.kernel.org, Evan Green , Tomasz Figa , iommu@lists.linux-foundation.org, linux-mediatek@lists.infradead.org, Krzysztof Kozlowski , anan.sun@mediatek.com, Greg Kroah-Hartman , linux-arm-kernel@lists.infradead.org References: <20201111123838.15682-1-yong.wu@mediatek.com> <20201111123838.15682-13-yong.wu@mediatek.com> From: Robin Murphy Message-ID: <55bb14ef-f674-e55c-0803-43d91093eccb@arm.com> Date: Thu, 26 Nov 2020 16:43:54 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <20201111123838.15682-13-yong.wu@mediatek.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 2020-11-11 12:38, Yong Wu wrote: > In attach device, it will update the pagetable base address register. > Move the hw_init function also here. Then it only need call > pm_runtime_get/put one time here if m4u has power domain. Doesn't that mean you'll end up writing most of the registers twice every time? (first from mtk_iommu_resume(), then again from mtk_iommu_hw_init()) It might be neater to have mtk_iommu_hw_init() simply populate the mtk_iommu_suspend_reg data with the initial values at probe time and manually call mtk_iommu_resume() if the hardware is already powered up at that point. Or maybe just don't bother saving those registers on suspend and put the initialisation directly in the resume path. Robin. > Signed-off-by: Yong Wu > --- > drivers/iommu/mtk_iommu.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > index 55f9b329e637..cfdf5ce696fd 100644 > --- a/drivers/iommu/mtk_iommu.c > +++ b/drivers/iommu/mtk_iommu.c > @@ -125,6 +125,8 @@ struct mtk_iommu_domain { > > static const struct iommu_ops mtk_iommu_ops; > > +static int mtk_iommu_hw_init(const struct mtk_iommu_data *data); > + > /* > * In M4U 4GB mode, the physical address is remapped as below: > * > @@ -380,12 +382,16 @@ static int mtk_iommu_attach_device(struct iommu_domain *domain, > { > struct mtk_iommu_data *data = dev_iommu_priv_get(dev); > struct mtk_iommu_domain *dom = to_mtk_domain(domain); > + int ret; > > if (!data) > return -ENODEV; > > /* Update the pgtable base address register of the M4U HW */ > if (!data->m4u_dom) { > + ret = mtk_iommu_hw_init(data); > + if (ret) > + return ret; > data->m4u_dom = dom; > writel(dom->cfg.arm_v7s_cfg.ttbr & MMU_PT_ADDR_MASK, > data->base + REG_MMU_PT_BASE_ADDR); > @@ -729,10 +735,6 @@ static int mtk_iommu_probe(struct platform_device *pdev) > > platform_set_drvdata(pdev, data); > > - ret = mtk_iommu_hw_init(data); > - if (ret) > - return ret; > - > ret = iommu_device_sysfs_add(&data->iommu, dev, NULL, > "mtk-iommu.%pa", &ioaddr); > if (ret) >