linux-kernel - Re: [PATCH v6 11/34] iommu/mediatek: Add a flag NON_STD

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Message-ID: <6668c7bf-6cee-b4e1-bb11-bf2399cc4874@gmail.com>
Date:   Thu, 28 Apr 2022 16:52:53 +0200
From:   Matthias Brugger <matthias.bgg@...il.com>
To:     Yong Wu <yong.wu@...iatek.com>, Joerg Roedel <joro@...tes.org>,
        Rob Herring <robh+dt@...nel.org>, Will Deacon <will@...nel.org>
Cc:     Robin Murphy <robin.murphy@....com>,
        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, xueqi.zhang@...iatek.com,
        yen-chang.chen@...iatek.com,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        mingyuan.ma@...iatek.com, yf.wang@...iatek.com,
        libo.kang@...iatek.com, chengci.xu@...iatek.com
Subject: Re: [PATCH v6 11/34] iommu/mediatek: Add a flag NON_STD_AXI



On 07/04/2022 09:57, Yong Wu wrote:
> Add a new flag NON_STD_AXI, All the previous SoC support this flag.
> Prepare for adding infra and apu iommu which don't support this.
> 
> Signed-off-by: Yong Wu <yong.wu@...iatek.com>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
> ---
>   drivers/iommu/mtk_iommu.c | 16 ++++++++++------
>   1 file changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 92f172a772d1..e7008a20ec74 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -122,6 +122,7 @@
>   #define IOVA_34_EN			BIT(8)
>   #define SHARE_PGTABLE			BIT(9) /* 2 HW share pgtable */
>   #define DCM_DISABLE			BIT(10)
> +#define NOT_STD_AXI_MODE		BIT(11)
>   
>   #define MTK_IOMMU_HAS_FLAG(pdata, _x) \
>   		((((pdata)->flags) & (_x)) == (_x))
> @@ -785,7 +786,8 @@ static int mtk_iommu_hw_init(const struct mtk_iommu_data *data)
>   		regval = 0;
>   	} else {
>   		regval = readl_relaxed(data->base + REG_MMU_MISC_CTRL);
> -		regval &= ~F_MMU_STANDARD_AXI_MODE_MASK;
> +		if (MTK_IOMMU_HAS_FLAG(data->plat_data, NOT_STD_AXI_MODE))
> +			regval &= ~F_MMU_STANDARD_AXI_MODE_MASK;

That means that for mt8195 infra we write back the very same value we read from 
REG_MMU_MISC_CTRL. Is this necessary?
Maybe we can come up with a different flag called STD_AXI_MODE and use something 
like
} else if (!MTK_IOMMU_HAS_FLAG(data->plat_data, \
                            STD_AXI_MODE)) {

Reason is that it makes more sense to add a flag for one specific iommu instead 
of adding a flag to the common case (iommu is not following standard AXI protocol).

What do you think?

Regards,
Matthias

>   		if (MTK_IOMMU_HAS_FLAG(data->plat_data, OUT_ORDER_WR_EN))
>   			regval &= ~F_MMU_IN_ORDER_WR_EN_MASK;
>   	}
> @@ -1058,7 +1060,8 @@ static const struct dev_pm_ops mtk_iommu_pm_ops = {
>   
>   static const struct mtk_iommu_plat_data mt2712_data = {
>   	.m4u_plat     = M4U_MT2712,
> -	.flags        = HAS_4GB_MODE | HAS_BCLK | HAS_VLD_PA_RNG | SHARE_PGTABLE,
> +	.flags        = HAS_4GB_MODE | HAS_BCLK | HAS_VLD_PA_RNG | SHARE_PGTABLE |
> +			NOT_STD_AXI_MODE,
>   	.hw_list      = &m4ulist,
>   	.inv_sel_reg  = REG_MMU_INV_SEL_GEN1,
>   	.iova_region  = single_domain,
> @@ -1068,7 +1071,8 @@ static const struct mtk_iommu_plat_data mt2712_data = {
>   
>   static const struct mtk_iommu_plat_data mt6779_data = {
>   	.m4u_plat      = M4U_MT6779,
> -	.flags         = HAS_SUB_COMM | OUT_ORDER_WR_EN | WR_THROT_EN,
> +	.flags         = HAS_SUB_COMM | OUT_ORDER_WR_EN | WR_THROT_EN |
> +			 NOT_STD_AXI_MODE,
>   	.inv_sel_reg   = REG_MMU_INV_SEL_GEN2,
>   	.iova_region   = single_domain,
>   	.iova_region_nr = ARRAY_SIZE(single_domain),
> @@ -1077,7 +1081,7 @@ static const struct mtk_iommu_plat_data mt6779_data = {
>   
>   static const struct mtk_iommu_plat_data mt8167_data = {
>   	.m4u_plat     = M4U_MT8167,
> -	.flags        = RESET_AXI | HAS_LEGACY_IVRP_PADDR,
> +	.flags        = RESET_AXI | HAS_LEGACY_IVRP_PADDR | NOT_STD_AXI_MODE,
>   	.inv_sel_reg  = REG_MMU_INV_SEL_GEN1,
>   	.iova_region  = single_domain,
>   	.iova_region_nr = ARRAY_SIZE(single_domain),
> @@ -1087,7 +1091,7 @@ static const struct mtk_iommu_plat_data mt8167_data = {
>   static const struct mtk_iommu_plat_data mt8173_data = {
>   	.m4u_plat     = M4U_MT8173,
>   	.flags	      = HAS_4GB_MODE | HAS_BCLK | RESET_AXI |
> -			HAS_LEGACY_IVRP_PADDR,
> +			HAS_LEGACY_IVRP_PADDR | NOT_STD_AXI_MODE,
>   	.inv_sel_reg  = REG_MMU_INV_SEL_GEN1,
>   	.iova_region  = single_domain,
>   	.iova_region_nr = ARRAY_SIZE(single_domain),
> @@ -1106,7 +1110,7 @@ static const struct mtk_iommu_plat_data mt8183_data = {
>   static const struct mtk_iommu_plat_data mt8192_data = {
>   	.m4u_plat       = M4U_MT8192,
>   	.flags          = HAS_BCLK | HAS_SUB_COMM | OUT_ORDER_WR_EN |
> -			  WR_THROT_EN | IOVA_34_EN,
> +			  WR_THROT_EN | IOVA_34_EN | NOT_STD_AXI_MODE,
>   	.inv_sel_reg    = REG_MMU_INV_SEL_GEN2,
>   	.iova_region    = mt8192_multi_dom,
>   	.iova_region_nr = ARRAY_SIZE(mt8192_multi_dom),