From: Miles Chen <miles.chen@mediatek.com>
To: Matthias Brugger <matthias.bgg@gmail.com>
Cc: devicetree@vger.kernel.org, wsd_upstream@mediatek.com,
David Hildenbrand <david@redhat.com>,
linux-kernel@vger.kernel.org, Mike Rapoport <rppt@linux.ibm.com>,
Chao Hao <chao.hao@mediatek.com>,
iommu@lists.linux-foundation.org,
Rob Herring <robh+dt@kernel.org>,
linux-mediatek@lists.infradead.org,
Yingjoe Chen <yingjoe.chen@mediatek.com>,
Christoph Hellwig <hch@lst.de>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 4/4] iommu/mediatek: check 4GB mode by reading infracfg
Date: Fri, 17 Jul 2020 16:26:31 +0800 [thread overview]
Message-ID: <1594974391.12796.25.camel@mtkswgap22> (raw)
In-Reply-To: <84333997-735c-4a91-6d47-1dcb5c4a6078@gmail.com>
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@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>
> > Signed-off-by: Miles Chen <miles.chen@mediatek.com>
> > ---
> > 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@mediatek.com>
> > */
> > -#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);
> >
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next prev parent reply other threads:[~2020-07-17 8:26 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-02 9:37 [PATCH 1/4] dt-bindings: mediatek: add mediatek,infracfg phandle Miles Chen
2020-07-02 9:37 ` [PATCH 2/4] arm64: dts: mt2712: add mediatek,infracfg to iommu Miles Chen
2020-07-02 9:37 ` [PATCH 3/4] arm64: dts: mt8173: " Miles Chen
2020-07-02 9:37 ` [PATCH 4/4] iommu/mediatek: check 4GB mode by reading infracfg Miles Chen
2020-07-15 21:05 ` Matthias Brugger
2020-07-17 8:26 ` Miles Chen [this message]
2020-07-15 20:51 ` [PATCH 1/4] dt-bindings: mediatek: add mediatek,infracfg phandle Rob Herring
2020-07-17 8:18 ` Miles Chen
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