[RESEND PATCH v4] iommu/mediatek: check 4GB mode by reading infracfg
Robin Murphy
robin.murphy at arm.com
Thu Aug 27 15:27:47 EDT 2020
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.chen@mediatek.com/
>> [2] https://lore.kernel.org/lkml/20200604080120.2628-1-miles.chen@mediatek.com/
>> [3] https://lore.kernel.org/lkml/20200715205120.GA778876@bogus/
>>
>> Cc: Mike Rapoport <rppt at linux.ibm.com>
>> Cc: David Hildenbrand <david at redhat.com>
>> Cc: Yong Wu <yong.wu at mediatek.com>
>> Cc: Yingjoe Chen <yingjoe.chen at mediatek.com>
>> Cc: Christoph Hellwig <hch at lst.de>
>> Cc: Rob Herring <robh at kernel.org>
>> Cc: Matthias Brugger <matthias.bgg at gmail.com>
>> Signed-off-by: Miles Chen <miles.chen at 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.wu at 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.
>> + 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.
>
> Then,
> Reviewed-by: Yong Wu <yong.wu at 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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