Messages in this thread | | | Subject | Re: [PATCH v2] iommu/mediatek: check 4GB mode by reading infracfg | From | Matthias Brugger <> | Date | Tue, 21 Jul 2020 11:40:41 +0200 |
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On 21/07/2020 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 > > [1] https://lkml.org/lkml/2020/6/3/733 > [2] https://lkml.org/lkml/2020/6/4/136 > [3] https://lkml.org/lkml/2020/7/15/1147 > > Cc: Mike Rapoport <rppt@linux.ibm.com> > Cc: David Hildenbrand <david@redhat.com> > Cc: Yong Wu <yong.wu@mediatek.com> > Cc: Yingjoe Chen <yingjoe.chen@mediatek.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Yong Wu <yong.wu@mediatek.com> > Cc: Chao Hao <chao.hao@mediatek.com> > Cc: Rob Herring <robh@kernel.org> > Cc: Matthias Brugger <matthias.bgg@gmail.com> > Signed-off-by: Miles Chen <miles.chen@mediatek.com> > --- > 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 <yong.wu@mediatek.com> > */ > -#include <linux/memblock.h> > #include <linux/bug.h> > #include <linux/clk.h> > #include <linux/component.h> > @@ -15,13 +14,16 @@ > #include <linux/iommu.h> > #include <linux/iopoll.h> > #include <linux/list.h> > +#include <linux/mfd/syscon.h> > #include <linux/of_address.h> > #include <linux/of_iommu.h> > #include <linux/of_irq.h> > #include <linux/of_platform.h> > #include <linux/platform_device.h> > +#include <linux/regmap.h> > #include <linux/slab.h> > #include <linux/spinlock.h> > +#include <linux/soc/mediatek/infracfg.h> > #include <asm/barrier.h> > #include <soc/mediatek/smi.h> > > @@ -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);
I think we should check m4u_plat instead to decide which compatible we have to look for. Another option would be to add a general compatible something like "mtk-infracfg" and search for that. That would need an update of all DTS having a infracfg compatible right now. After thinking twice, this would break newer kernel with older device tree, so maybe it's better to go with m4u_plat switch statement.
Regards, Matthias
> + > + } > + 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, >
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