linux-kernel - Re: [PATCH v3 22/33] iommu/mediatek: Add PCIe support

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Date:   Tue, 4 Jan 2022 16:54:57 +0100
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     Yong Wu <yong.wu@...iatek.com>, Joerg Roedel <joro@...tes.org>,
        Rob Herring <robh+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Tomasz Figa <tfiga@...omium.org>,
        linux-mediatek@...ts.infradead.org, srv_heupstream@...iatek.com,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        iommu@...ts.linux-foundation.org,
        Hsin-Yi Wang <hsinyi@...omium.org>, youlin.pei@...iatek.com,
        anan.sun@...iatek.com, chao.hao@...iatek.com,
        yen-chang.chen@...iatek.com
Subject: Re: [PATCH v3 22/33] iommu/mediatek: Add PCIe support

Il 23/09/21 13:58, Yong Wu ha scritto:
> Currently the code for of_iommu_configure_dev_id is like this:
> 
> static int of_iommu_configure_dev_id(struct device_node *master_np,
>                                       struct device *dev,
>                                       const u32 *id)
> {
>         struct of_phandle_args iommu_spec = { .args_count = 1 };
> 
>         err = of_map_id(master_np, *id, "iommu-map",
>                         "iommu-map-mask", &iommu_spec.np,
>                         iommu_spec.args);
> ...
> }
> 
> It supports only one id output. BUT our PCIe HW has two ID(one is for
> writing, the other is for reading). I'm not sure if we should change
> of_map_id to support output MAX_PHANDLE_ARGS.
> 
> Here add the solution in ourselve drivers. If it's pcie case, enable one
> more bit.
> 
> Not all infra iommu support PCIe, thus add a PCIe support flag here.
> 
> Signed-off-by: Yong Wu <yong.wu@...iatek.com>
> ---
>   drivers/iommu/mtk_iommu.c | 21 ++++++++++++++++++++-
>   1 file changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 37d6dfb4feab..3f1fd8036345 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -20,6 +20,7 @@
>   #include <linux/of_address.h>
>   #include <linux/of_irq.h>
>   #include <linux/of_platform.h>
> +#include <linux/pci.h>
>   #include <linux/platform_device.h>
>   #include <linux/pm_runtime.h>
>   #include <linux/regmap.h>
> @@ -132,6 +133,7 @@
>   #define MTK_IOMMU_TYPE_MM		(0x0 << 13)
>   #define MTK_IOMMU_TYPE_INFRA		(0x1 << 13)
>   #define MTK_IOMMU_TYPE_MASK		(0x3 << 13)
> +#define IFA_IOMMU_PCIe_SUPPORT		BIT(15)

This definition looks like "breaking" the naming convention that's used in this
driver... what about MTK_INFRA_IOMMU_PCIE_SUPPORT?

>   
>   #define MTK_IOMMU_HAS_FLAG(pdata, _x)	(!!(((pdata)->flags) & (_x)))
>   
> @@ -401,8 +403,11 @@ static int mtk_iommu_config(struct mtk_iommu_data *data, struct device *dev,
>   				larb_mmu->mmu &= ~MTK_SMI_MMU_EN(portid);
>   		} else if (MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_INFRA)) {
>   			peri_mmuen_msk = BIT(portid);
> -			peri_mmuen = enable ? peri_mmuen_msk : 0;
> +			/* PCIdev has only one output id, enable the next writing bit for PCIe */
> +			if (dev_is_pci(dev))
> +				peri_mmuen_msk |= BIT(portid + 1);
>   
> +			peri_mmuen = enable ? peri_mmuen_msk : 0;
>   			ret = regmap_update_bits(data->pericfg, PERICFG_IOMMU_1,
>   						 peri_mmuen_msk, peri_mmuen);
>   			if (ret)
> @@ -977,6 +982,15 @@ static int mtk_iommu_probe(struct platform_device *pdev)
>   		ret = component_master_add_with_match(dev, &mtk_iommu_com_ops, match);
>   		if (ret)
>   			goto out_bus_set_null;
> +	} else if (MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_INFRA) &&
> +		   MTK_IOMMU_HAS_FLAG(data->plat_data, IFA_IOMMU_PCIe_SUPPORT)) {
> +		#ifdef CONFIG_PCI

Please fix the indentation of this ifdef (do not indent).

> +		if (!iommu_present(&pci_bus_type)) {
> +			ret = bus_set_iommu(&pci_bus_type, &mtk_iommu_ops);
> +			if (ret) /* PCIe fail don't affect platform_bus. */
> +				goto out_list_del;
> +		}
> +		#endif
>   	}
>   	return ret;
>   
> @@ -1007,6 +1021,11 @@ static int mtk_iommu_remove(struct platform_device *pdev)
>   	if (MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_MM)) {
>   		device_link_remove(data->smicomm_dev, &pdev->dev);
>   		component_master_del(&pdev->dev, &mtk_iommu_com_ops);
> +	} else if (MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_INFRA) &&
> +		   MTK_IOMMU_HAS_FLAG(data->plat_data, IFA_IOMMU_PCIe_SUPPORT)) {
> +		#ifdef CONFIG_PCI

ditto.

> +		bus_set_iommu(&pci_bus_type, NULL);
> +		#endif
>   	}
>   	pm_runtime_disable(&pdev->dev);
>   	devm_free_irq(&pdev->dev, data->irq, data);
>