Messages in this thread Patch in this message | | | Subject | Re: [RESEND PATCH v4] iommu/mediatek: check 4GB mode by reading infracfg | From | Robin Murphy <> | Date | Thu, 27 Aug 2020 20:27:47 +0100 |
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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 <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: Rob Herring <robh@kernel.org> >> Cc: Matthias Brugger <matthias.bgg@gmail.com> >> Signed-off-by: Miles Chen <miles.chen@mediatek.com> >> >> --- >> >> 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 <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> >> >> @@ -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 <yong.wu@mediatek.com> > > >> + 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 >
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