linux-kernel - [RFC PATCH 4/8] iommu/arm-smmu-v3: Add implementation for MT8196 APU SMMU

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Message-ID: <20250616025628.25454-5-xueqi.zhang@mediatek.com>
Date: Mon, 16 Jun 2025 10:56:10 +0800
From: Xueqi Zhang <xueqi.zhang@...iatek.com>
To: Yong Wu <yong.wu@...iatek.com>, Will Deacon <will@...nel.org>, Robin
 Murphy <robin.murphy@....com>, Joerg Roedel <joro@...tes.org>, Rob Herring
	<robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
	<conor+dt@...nel.org>, Matthias Brugger <matthias.bgg@...il.com>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
CC: <Project_Global_Chrome_Upstream_Group@...iatek.com>, Ning li
	<ning.li@...iatek.com>, <linux-mediatek@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>,
	<devicetree@...r.kernel.org>, <iommu@...ts.linux.dev>, Xueqi Zhang
	<xueqi.zhang@...iatek.com>
Subject: [RFC PATCH 4/8] iommu/arm-smmu-v3: Add implementation for MT8196 APU SMMU

Add a special implementation for mediatek APU SMMU. APU SMMU need to
wait APU SMMU's power which depends on APU driver. Therefore, add the
label mediatek,smmu-parent to point to the power device that the
smmu depends on. If the device has not finished probing, return
-EPROBE_DEFER.

Signed-off-by: Xueqi Zhang <xueqi.zhang@...iatek.com>
---
 .../arm/arm-smmu-v3/arm-smmu-v3-mediatek.c    | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-mediatek.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-mediatek.c
index c00ee687d839..48290366e596 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-mediatek.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-mediatek.c
@@ -15,10 +15,12 @@
 #include "arm-smmu-v3.h"
 
 #define MTK_SMMU_COMP_STR_LEN		64
+#define SMMU_REQUIRE_PARENT		BIT(5)
 #define MTK_SMMU_HAS_FLAG(pdata, _x)    (!!(((pdata)->flags) & (_x)))
 
 enum mtk_smmu_type {
 	MTK_SMMU_MM,
+	MTK_SMMU_APU,
 	MTK_SMMU_TYPE_NUM,
 };
 
@@ -36,12 +38,18 @@ static const struct mtk_smmu_v3_plat mt8196_data_mm = {
 	.smmu_type		= MTK_SMMU_MM,
 };
 
+static const struct mtk_smmu_v3_plat mt8196_data_apu = {
+	.smmu_type		= MTK_SMMU_APU,
+	.flags			= SMMU_REQUIRE_PARENT,
+};
+
 struct mtk_smmu_v3_of_device_data {
 	char			compatible[MTK_SMMU_COMP_STR_LEN];
 	const void		*data;
 };
 
 static const struct mtk_smmu_v3_of_device_data mtk_smmu_v3_of_ids[] = {
+	{ .compatible = "mediatek,mt8196-apu-smmu", .data = &mt8196_data_apu},
 	{ .compatible = "mediatek,mt8196-mm-smmu", .data = &mt8196_data_mm},
 };
 
@@ -79,5 +87,29 @@ struct arm_smmu_device *arm_smmu_v3_impl_mtk_init(struct arm_smmu_device *smmu)
 		return ERR_PTR(-EINVAL);
 	}
 
+	if (MTK_SMMU_HAS_FLAG(mtk_smmu_v3->plat_data, SMMU_REQUIRE_PARENT)) {
+		parent_node = of_parse_phandle(dev->of_node, "mediatek,smmu-parent", 0);
+		if (!parent_node) {
+			dev_err(dev, "Lack its parent node.\n");
+			return ERR_PTR(-EINVAL);
+		}
+		if (!of_device_is_available(parent_node)) {
+			of_node_put(parent_node);
+			return ERR_PTR(-EINVAL);
+		}
+
+		parent_pdev = of_find_device_by_node(parent_node);
+		of_node_put(parent_node);
+		if (!parent_pdev) {
+			dev_err(dev, "Lack its parent devices.\n");
+			return ERR_PTR(-ENODEV);
+		}
+
+		if (!platform_get_drvdata(parent_pdev)) {
+			dev_err(dev, "Delay since its parent driver is not ready.\n");
+			return ERR_PTR(-EPROBE_DEFER);
+		}
+	}
+
 	return &mtk_smmu_v3->smmu;
 }
-- 
2.46.0