On Tue, 2020-07-21 at 11:10 +0200, David Hildenbrand wrote: > On 21.07.20 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 > > Nit: We tend to place such information below the "---" (adding a second > one) such that this information is discarded when the patch is picked up.
Thanks, I'll add a "---" before the "Change since..." in patch v3. > > > > > [1] > > https://urldefense.com/v3/__https://lkml.org/lkml/2020/6/3/733__;!!CTRNKA9wMg0ARbw!wrP2H0azuZkTHSnM_ETki4kT_FMF0Cl7abQX8tIHX0iTr65JkvMCe4jDt84d_YhBrA$ > > > > [2] > > https://urldefense.com/v3/__https://lkml.org/lkml/2020/6/4/136__;!!CTRNKA9wMg0ARbw!wrP2H0azuZkTHSnM_ETki4kT_FMF0Cl7abQX8tIHX0iTr65JkvMCe4jDt86IGhmouQ$ > > > > [3] > > https://urldefense.com/v3/__https://lkml.org/lkml/2020/7/15/1147__;!!CTRNKA9wMg0ARbw!wrP2H0azuZkTHSnM_ETki4kT_FMF0Cl7abQX8tIHX0iTr65JkvMCe4jDt855z4xdqw$ > > > > > > 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); > > (I am absolutely not familiar with syscon_regmap_lookup_by ..., I am > missing some context, so sorry for the stupid questions) > > Who sets the regmap value and based on what? Who decides that 4GB mode > is supported or not? And who decides if 4GB mode is *required* or not? >
