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Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kBNZG-0006J3-3x; Thu, 27 Aug 2020 19:28:14 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kBNYv-00068l-AK; Thu, 27 Aug 2020 19:27:55 +0000 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 BBE3231B; Thu, 27 Aug 2020 12:27:50 -0700 (PDT) Received: from [10.57.40.122] (unknown [10.57.40.122]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A331E3F68F; Thu, 27 Aug 2020 12:27:48 -0700 (PDT) Subject: Re: [RESEND PATCH v4] iommu/mediatek: check 4GB mode by reading infracfg To: Yong Wu , Miles Chen References: <20200826085618.2889-1-miles.chen@mediatek.com> <1598506280.19851.5.camel@mhfsdcap03> From: Robin Murphy Message-ID: Date: Thu, 27 Aug 2020 20:27:47 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <1598506280.19851.5.camel@mhfsdcap03> Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200827_152753_699468_716C3FA0 X-CRM114-Status: GOOD ( 27.89 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Rob Herring , wsd_upstream@mediatek.com, David Hildenbrand , Joerg Roedel , linux-kernel@vger.kernel.org, Mike Rapoport , iommu@lists.linux-foundation.org, linux-mediatek@lists.infradead.org, Matthias Brugger , Yingjoe Chen , Christoph Hellwig , linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2020-08-27 06:31, Yong Wu wrote: > On Wed, 2020-08-26 at 16:56 +0800, 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. >> >> [1] https://lore.kernel.org/lkml/20200603161132.2441-1-miles.chen@mediatek.com/ >> [2] https://lore.kernel.org/lkml/20200604080120.2628-1-miles.chen@mediatek.com/ >> [3] https://lore.kernel.org/lkml/20200715205120.GA778876@bogus/ >> >> Cc: Mike Rapoport >> Cc: David Hildenbrand >> Cc: Yong Wu >> Cc: Yingjoe Chen >> Cc: Christoph Hellwig >> Cc: Rob Herring >> Cc: Matthias Brugger >> Signed-off-by: Miles Chen >> >> --- >> >> Change since v3 >> - use lore.kernel.org links >> - move "change since..." after "---" >> >> Change since v2: >> - determine compatible string by m4u_plat >> - rebase to next-20200720 >> - add "---" >> >> Change since v1: >> - remove the phandle usage, search for infracfg instead [3] >> - use infracfg instead of infracfg_regmap >> - move infracfg definitaions to linux/soc/mediatek/infracfg.h >> - update enable_4GB only when has_4gb_mode >> --- >> drivers/iommu/mtk_iommu.c | 34 +++++++++++++++++++++++---- >> include/linux/soc/mediatek/infracfg.h | 3 +++ >> 2 files changed, 32 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c >> index 785b228d39a6..adc350150492 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 >> >> @@ -640,8 +642,11 @@ 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; >> + char *p; >> >> data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); >> if (!data) >> @@ -655,10 +660,29 @@ 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 (!MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE)) >> - data->enable_4GB = false; >> + data->enable_4GB = false; Nit: this isn't really necessary, since the structure is kzalloc()ed. >> + if (MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE)) { >> + switch (data->plat_data->m4u_plat) { >> + case M4U_MT2712: >> + p = "mediatek,mt2712-infracfg"; >> + break; >> + case M4U_MT8173: >> + p = "mediatek,mt8173-infracfg"; >> + break; >> + default: >> + p = NULL; >> + } >> + > > This can be simplified: > > if (data->plat_data->m4u_plat == M4U_MT2712) > p = "mediatek,mt2712-infracfg"; > else if(data->plat_data->m4u_plat == M4U_MT8173) > p = "mediatek,mt8173-infracfg"; > else > return -EINVAL; Right, at this point the HAS_4GB_MODE flag is entirely redundant and should be removed. FWIW I still think your suggestion of putting the infracfg names into plat_data would be even better and cleaner - there's plenty of precedent for that sort of thing (see "git grep '\.clk_name'" for example). Robin. > > Then, > Reviewed-by: Yong Wu > > >> + infracfg = syscon_regmap_lookup_by_compatible(p); >> + >> + 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); >> + } >> >> res = platform_get_resource(pdev, IORESOURCE_MEM, 0); >> data->base = devm_ioremap_resource(dev, res); >> diff --git a/include/linux/soc/mediatek/infracfg.h b/include/linux/soc/mediatek/infracfg.h >> index fd25f0148566..233463d789c6 100644 >> --- a/include/linux/soc/mediatek/infracfg.h >> +++ b/include/linux/soc/mediatek/infracfg.h >> @@ -32,6 +32,9 @@ >> #define MT7622_TOP_AXI_PROT_EN_WB (BIT(2) | BIT(6) | \ >> BIT(7) | BIT(8)) >> >> +#define REG_INFRA_MISC 0xf00 >> +#define F_DDR_4GB_SUPPORT_EN BIT(13) >> + >> int mtk_infracfg_set_bus_protection(struct regmap *infracfg, u32 mask, >> bool reg_update); >> int mtk_infracfg_clear_bus_protection(struct regmap *infracfg, u32 mask, > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel