On Thu, 2020-08-27 at 20:27 +0100, Robin Murphy wrote:
> On 2020-08-27 06:31, Yong Wu wrote:
> > On Wed, 2020-08-26 at 16:56 +0800, 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.
> >>
> >> [1]
> >> https://lore.kernel.org/lkml/20200603161132.2441-1-miles.c...@mediatek.com/
> >> [2]
> >> https://lore.kernel.org/lkml/20200604080120.2628-1-miles.c...@mediatek.com/
> >> [3] https://lore.kernel.org/lkml/20200715205120.GA778876@bogus/
> >>
> >> 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: Rob Herring <r...@kernel.org>
> >> Cc: Matthias Brugger <matthias....@gmail.com>
> >> Signed-off-by: Miles Chen <miles.c...@mediatek.com>
> >>
> >> ---
> >>
> >> Change since v3
> >> - use lore.kernel.org links
> >> - move "change since..." after "---"
> >>
> >> Change since v2:
> >> - determine compatible string by m4u_plat
> >> - rebase to next-20200720
> >> - add "---"
> >>
> >> Change since v1:
> >> - remove the phandle usage, search for infracfg instead [3]
> >> - use infracfg instead of infracfg_regmap
> >> - move infracfg definitaions to linux/soc/mediatek/infracfg.h
> >> - update enable_4GB only when has_4gb_mode
> >> ---
> >> drivers/iommu/mtk_iommu.c | 34 +++++++++++++++++++++++----
> >> include/linux/soc/mediatek/infracfg.h | 3 +++
> >> 2 files changed, 32 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> >> index 785b228d39a6..adc350150492 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>
> >>
> >> @@ -640,8 +642,11 @@ 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;
> >> + char *p;
> >>
> >> data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> >> if (!data)
> >> @@ -655,10 +660,29 @@ 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 (!MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE))
> >> - data->enable_4GB = false;
> >> + data->enable_4GB = false;
>
> Nit: this isn't really necessary, since the structure is kzalloc()ed.
Thanks for the comment, I will remove this this in v5.
>
> >> + if (MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE)) {
> >> + switch (data->plat_data->m4u_plat) {
> >> + case M4U_MT2712:
> >> + p = "mediatek,mt2712-infracfg";
> >> + break;
> >> + case M4U_MT8173:
> >> + p = "mediatek,mt8173-infracfg";
> >> + break;
> >> + default:
> >> + p = NULL;
> >> + }
> >> +
> >
> > This can be simplified:
> >
> > if (data->plat_data->m4u_plat == M4U_MT2712)
> > p = "mediatek,mt2712-infracfg";
> > else if(data->plat_data->m4u_plat == M4U_MT8173)
> > p = "mediatek,mt8173-infracfg";
> > else
> > return -EINVAL;
>
> Right, at this point the HAS_4GB_MODE flag is entirely redundant and
> should be removed. FWIW I still think your suggestion of putting the
> infracfg names into plat_data would be even better and cleaner - there's
> plenty of precedent for that sort of thing (see "git grep '\.clk_name'"
> for example).
>
> Robin.
hmm, I have no strong opinion about this. We have discussed this
approach before and built this patch based on the discussion.
https://lore.kernel.org/patchwork/patch/1276801/
Miles
>
> >
> > Then,
> > Reviewed-by: Yong Wu <yong...@mediatek.com>
> >
> >
> >> + infracfg = syscon_regmap_lookup_by_compatible(p);
> >> +
> >> + 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);
> >> + }
> >>
> >> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >> data->base = devm_ioremap_resource(dev, res);
> >> diff --git a/include/linux/soc/mediatek/infracfg.h
> >> b/include/linux/soc/mediatek/infracfg.h
> >> index fd25f0148566..233463d789c6 100644
> >> --- a/include/linux/soc/mediatek/infracfg.h
> >> +++ b/include/linux/soc/mediatek/infracfg.h
> >> @@ -32,6 +32,9 @@
> >> #define MT7622_TOP_AXI_PROT_EN_WB (BIT(2) | BIT(6) | \
> >> BIT(7) | BIT(8))
> >>
> >> +#define REG_INFRA_MISC 0xf00
> >> +#define F_DDR_4GB_SUPPORT_EN BIT(13)
> >> +
> >> int mtk_infracfg_set_bus_protection(struct regmap *infracfg, u32 mask,
> >> bool reg_update);
> >> int mtk_infracfg_clear_bus_protection(struct regmap *infracfg, u32 mask,
> >
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> >
