In previous disscusion [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 unexported symbol max_pfn. [1] https://lkml.org/lkml/2020/6/3/733 [2] https://lkml.org/lkml/2020/6/4/136 Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: Yong Wu <yong.wu@xxxxxxxxxxxx> Cc: Yingjoe Chen <yingjoe.chen@xxxxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Miles Chen <miles.chen@xxxxxxxxxxxx> --- drivers/iommu/mtk_iommu.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c index 2be96f1cdbd2..09be57bd8d74 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@xxxxxxxxxxxx> */ -#include <linux/memblock.h> #include <linux/bug.h> #include <linux/clk.h> #include <linux/component.h> @@ -15,11 +14,13 @@ #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 <asm/barrier.h> @@ -91,6 +92,9 @@ #define F_MMU_INT_ID_LARB_ID(a) (((a) >> 7) & 0x7) #define F_MMU_INT_ID_PORT_ID(a) (((a) >> 2) & 0x1f) +#define REG_INFRA_MISC 0xf00 +#define F_DDR_4GB_SUPPORT_EN BIT(13) + #define MTK_PROTECT_PA_ALIGN 128 /* @@ -599,8 +603,10 @@ static int mtk_iommu_probe(struct platform_device *pdev) struct resource *res; resource_size_t ioaddr; struct component_match *match = NULL; + struct regmap *infracfg_regmap; void *protect; int i, larb_nr, ret; + u32 val; data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); if (!data) @@ -614,10 +620,18 @@ 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) + if (data->plat_data->has_4gb_mode) { + infracfg_regmap = syscon_regmap_lookup_by_phandle(dev->of_node, + "mediatek,infracfg"); + if (IS_ERR(infracfg_regmap)) + return PTR_ERR(infracfg_regmap); + ret = regmap_read(infracfg_regmap, REG_INFRA_MISC, &val); + if (ret) + return ret; + data->enable_4GB = !!(val & F_DDR_4GB_SUPPORT_EN); + } else { data->enable_4GB = false; + } res = platform_get_resource(pdev, IORESOURCE_MEM, 0); data->base = devm_ioremap_resource(dev, res); -- 2.18.0
