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 <r...@linux.ibm.com> Cc: David Hildenbrand <da...@redhat.com> Cc: Yong Wu <yong...@mediatek.com> Cc: Yingjoe Chen <yingjoe.c...@mediatek.com> Cc: Christoph Hellwig <h...@lst.de> Cc: Yong Wu <yong...@mediatek.com> Cc: Chao Hao <chao....@mediatek.com> Cc: Rob Herring <r...@kernel.org> Cc: Matthias Brugger <matthias....@gmail.com> Signed-off-by: Miles Chen <miles.c...@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...@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); + + } + 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, -- 2.18.0