On Wed, 2020-07-15 at 23:05 +0200, Matthias Brugger wrote: > > On 02/07/2020 11:37, Miles Chen wrote: > > 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://urldefense.com/v3/__https://lkml.org/lkml/2020/6/3/733__;!!CTRNKA9wMg0ARbw!16gAfVnSY87W4t5kE4iw20QPxBgS_SHBvPKlePKU7CGIb18nUzuRUjHumcf4oYVhIQ$ > > [2] https://urldefense.com/v3/__https://lkml.org/lkml/2020/6/4/136__;!!CTRNKA9wMg0ARbw!16gAfVnSY87W4t5kE4iw20QPxBgS_SHBvPKlePKU7CGIb18nUzuRUjHumcfr4i9p5g$ > > > > 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) > > + > > As this is used for infracfg, I think it would be good to add it to > include/linux/soc/mediatek/infracfg.h and include that file here. Thanks for your comment. ok. I'll do this in next version. > > > #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; > > Maybe call it just infracfg. ok. I'll do this in next version. > > > 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); > > Do we need to error out, or could we be conservative and set endable_4GB = false? We have to error out in this case because the 4gb_mode setting must be consistent with the h/w setting. > > > + 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; > > Move that before the if() and update enable_4GB only in case of has_4gb_mode. ok. I'll do this in next version. Miles > > > + } > > > > res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > data->base = devm_ioremap_resource(dev, res); > >
