On Wed, 2020-07-22 at 15:17 +0800, Miles Chen wrote: > On Tue, 2020-07-21 at 23:19 +0200, Matthias Brugger wrote: > > > > On 21/07/2020 13:24, Yong Wu wrote: > > > On Tue, 2020-07-21 at 11:40 +0200, Matthias Brugger wrote: > > >> > > >> On 21/07/2020 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 > > >>> > > >>> [1] > > >>> https://urldefense.com/v3/__https://lkml.org/lkml/2020/6/3/733__;!!CTRNKA9wMg0ARbw!w5YjY83YRL9_ijgXHwB1x2Dnb5BqiFUI8H5IAyAWWFMvUJKI9Qbj_zta2AaiFZejiQ$ > > >>> > > >>> [2] > > >>> https://urldefense.com/v3/__https://lkml.org/lkml/2020/6/4/136__;!!CTRNKA9wMg0ARbw!w5YjY83YRL9_ijgXHwB1x2Dnb5BqiFUI8H5IAyAWWFMvUJKI9Qbj_zta2Aa9U2yQyg$ > > >>> > > >>> [3] > > >>> https://urldefense.com/v3/__https://lkml.org/lkml/2020/7/15/1147__;!!CTRNKA9wMg0ARbw!w5YjY83YRL9_ijgXHwB1x2Dnb5BqiFUI8H5IAyAWWFMvUJKI9Qbj_zta2Aaxpk_Wjw$ > > >>> > > >>> > > >>> 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); > > >> > > >> I think we should check m4u_plat instead to decide which compatible we > > >> have to > > >> look for. > > >> Another option would be to add a general compatible something like > > >> "mtk-infracfg" and search for that. That would need an update of all DTS > > >> having > > >> a infracfg compatible right now. After thinking twice, this would break > > >> newer > > >> kernel with older device tree, so maybe it's better to go with m4u_plat > > >> switch > > >> statement. > > > > > > Add a "char *infracfg" in the plat_data, Use the mt2712, mt8173 > > > corresponding string in it. If it is NULL, It means the "enable_4GB" > > > always is false. Then we also can remove the flag "has_4gb_mode". > > > > > > is this OK? > > > > > > > It's an option, but I personally find that a bit hacky. > > Thanks Yong and Matthias for your comment. > I will try adding a char *infracfg in patch v3. >
I misunderstood the comment. I should check m4u_plat to decide which string to look for, not adding a char *infracfg in patch v3. Miles > > > > > Regards, > > Matthias >
