Messages in this thread | | | Subject | Re: [PATCH v2] iommu/mediatek: check 4GB mode by reading infracfg | From | Miles Chen <> | Date | Wed, 22 Jul 2020 15:17:18 +0800 |
| |
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 <rppt@linux.ibm.com> > >>> Cc: David Hildenbrand <david@redhat.com> > >>> Cc: Yong Wu <yong.wu@mediatek.com> > >>> Cc: Yingjoe Chen <yingjoe.chen@mediatek.com> > >>> Cc: Christoph Hellwig <hch@lst.de> > >>> Cc: Yong Wu <yong.wu@mediatek.com> > >>> Cc: Chao Hao <chao.hao@mediatek.com> > >>> Cc: Rob Herring <robh@kernel.org> > >>> Cc: Matthias Brugger <matthias.bgg@gmail.com> > >>> Signed-off-by: Miles Chen <miles.chen@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.wu@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.
> > Regards, > Matthias
| |