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X-UUID: d331a230923941bb81206dcd421e9959-20200722 Received: from mtkexhb01.mediatek.inc [(172.21.101.102)] by mailgw02.mediatek.com (envelope-from ) (Cellopoint E-mail Firewall v4.1.10 Build 0809 with TLS) with ESMTP id 160040994; Wed, 22 Jul 2020 15:15:53 +0800 Received: from mtkcas07.mediatek.inc (172.21.101.84) by mtkmbs01n2.mediatek.inc (172.21.101.79) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 22 Jul 2020 15:15:49 +0800 Received: from [172.21.77.33] (172.21.77.33) by mtkcas07.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Wed, 22 Jul 2020 15:15:50 +0800 Message-ID: <1595402150.10848.1.camel@mtkswgap22> Subject: Re: [PATCH v2] iommu/mediatek: check 4GB mode by reading infracfg From: Miles Chen To: David Hildenbrand Date: Wed, 22 Jul 2020 15:15:50 +0800 In-Reply-To: References: <20200721021619.25575-1-miles.chen@mediatek.com> X-Mailer: Evolution 3.2.3-0ubuntu6 MIME-Version: 1.0 X-TM-SNTS-SMTP: 125A2A6B996131DF2178586BE457C60F26919FB3EC0293BA66AB66B8DF6B504B2000:8 X-MTK: N Cc: Rob Herring , wsd_upstream@mediatek.com, linux-kernel@vger.kernel.org, Mike Rapoport , Chao Hao , iommu@lists.linux-foundation.org, linux-mediatek@lists.infradead.org, Matthias Brugger , Yingjoe Chen , Christoph Hellwig , linux-arm-kernel@lists.infradead.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Tue, 2020-07-21 at 11:10 +0200, David Hildenbrand wrote: > On 21.07.20 04:16, Miles Chen wrote: > > In previous discussion [1] and [2], we found that it is risky to > > use max_pfn or totalram_pages to tell if 4GB mode is enabled. > > > > Check 4GB mode by reading infracfg register, remove the usage > > of the un-exported symbol max_pfn. > > > > This is a step towards building mtk_iommu as a kernel module. > > > > Change since v1: > > 1. remove the phandle usage, search for infracfg instead [3] > > 2. use infracfg instead of infracfg_regmap > > 3. move infracfg definitaions to linux/soc/mediatek/infracfg.h > > 4. update enable_4GB only when has_4gb_mode > > Nit: We tend to place such information below the "---" (adding a second > one) such that this information is discarded when the patch is picked up. Thanks, I'll add a "---" before the "Change since..." in patch v3. > > > > > [1] https://urldefense.com/v3/__https://lkml.org/lkml/2020/6/3/733__;!!CTRNKA9wMg0ARbw!wrP2H0azuZkTHSnM_ETki4kT_FMF0Cl7abQX8tIHX0iTr65JkvMCe4jDt84d_YhBrA$ > > [2] https://urldefense.com/v3/__https://lkml.org/lkml/2020/6/4/136__;!!CTRNKA9wMg0ARbw!wrP2H0azuZkTHSnM_ETki4kT_FMF0Cl7abQX8tIHX0iTr65JkvMCe4jDt86IGhmouQ$ > > [3] https://urldefense.com/v3/__https://lkml.org/lkml/2020/7/15/1147__;!!CTRNKA9wMg0ARbw!wrP2H0azuZkTHSnM_ETki4kT_FMF0Cl7abQX8tIHX0iTr65JkvMCe4jDt855z4xdqw$ > > > > Cc: Mike Rapoport > > Cc: David Hildenbrand > > Cc: Yong Wu > > Cc: Yingjoe Chen > > Cc: Christoph Hellwig > > Cc: Yong Wu > > Cc: Chao Hao > > Cc: Rob Herring > > Cc: Matthias Brugger > > Signed-off-by: Miles Chen > > --- > > drivers/iommu/mtk_iommu.c | 26 +++++++++++++++++++++----- > > include/linux/soc/mediatek/infracfg.h | 3 +++ > > 2 files changed, 24 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > > index 2be96f1cdbd2..16765f532853 100644 > > --- a/drivers/iommu/mtk_iommu.c > > +++ b/drivers/iommu/mtk_iommu.c > > @@ -3,7 +3,6 @@ > > * Copyright (c) 2015-2016 MediaTek Inc. > > * Author: Yong Wu > > */ > > -#include > > #include > > #include > > #include > > @@ -15,13 +14,16 @@ > > #include > > #include > > #include > > +#include > > #include > > #include > > #include > > #include > > #include > > +#include > > #include > > #include > > +#include > > #include > > #include > > > > @@ -599,8 +601,10 @@ static int mtk_iommu_probe(struct platform_device *pdev) > > struct resource *res; > > resource_size_t ioaddr; > > struct component_match *match = NULL; > > + struct regmap *infracfg; > > void *protect; > > int i, larb_nr, ret; > > + u32 val; > > > > data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > > if (!data) > > @@ -614,10 +618,22 @@ static int mtk_iommu_probe(struct platform_device *pdev) > > return -ENOMEM; > > data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN); > > > > - /* Whether the current dram is over 4GB */ > > - data->enable_4GB = !!(max_pfn > (BIT_ULL(32) >> PAGE_SHIFT)); > > - if (!data->plat_data->has_4gb_mode) > > - data->enable_4GB = false; > > + data->enable_4GB = false; > > + if (data->plat_data->has_4gb_mode) { > > + infracfg = syscon_regmap_lookup_by_compatible( > > + "mediatek,mt8173-infracfg"); > > + if (IS_ERR(infracfg)) { > > + infracfg = syscon_regmap_lookup_by_compatible( > > + "mediatek,mt2712-infracfg"); > > + if (IS_ERR(infracfg)) > > + return PTR_ERR(infracfg); > > + > > + } > > + ret = regmap_read(infracfg, REG_INFRA_MISC, &val); > > + if (ret) > > + return ret; > > + data->enable_4GB = !!(val & F_DDR_4GB_SUPPORT_EN); > > (I am absolutely not familiar with syscon_regmap_lookup_by ..., I am > missing some context, so sorry for the stupid questions) > > Who sets the regmap value and based on what? Who decides that 4GB mode > is supported or not? And who decides if 4GB mode is *required* or not? > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu