iommu/mediatek: Add a flag DCM_DISABLE

In the infra iommu, we should disable DCM. add a new flag for this.
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Link: https://lore.kernel.org/r/20220503071427.2285-12-yong.wu@mediatek.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/mtk_iommu.c

@@ -51,6 +51,8 @@
 #define F_MMU_STANDARD_AXI_MODE_MASK		(BIT(3) | BIT(19))
 
 #define REG_MMU_DCM_DIS				0x050
+#define F_MMU_DCM				BIT(8)
+
 #define REG_MMU_WR_LEN_CTRL			0x054
 #define F_MMU_WR_THROT_DIS_MASK			(BIT(5) | BIT(21))
 
@@ -119,6 +121,7 @@
 #define HAS_LEGACY_IVRP_PADDR		BIT(7)
 #define IOVA_34_EN			BIT(8)
 #define SHARE_PGTABLE			BIT(9) /* 2 HW share pgtable */
+#define DCM_DISABLE			BIT(10)
 
 #define MTK_IOMMU_HAS_FLAG(pdata, _x) \
 		((((pdata)->flags) & (_x)) == (_x))
@@ -765,7 +768,11 @@ static int mtk_iommu_hw_init(const struct mtk_iommu_data *data)
 		regval = F_MMU_VLD_PA_RNG(7, 4);
 		writel_relaxed(regval, data->base + REG_MMU_VLD_PA_RNG);
 	}
-	writel_relaxed(0, data->base + REG_MMU_DCM_DIS);
+	if (MTK_IOMMU_HAS_FLAG(data->plat_data, DCM_DISABLE))
+		writel_relaxed(F_MMU_DCM, data->base + REG_MMU_DCM_DIS);
+	else
+		writel_relaxed(0, data->base + REG_MMU_DCM_DIS);
+
 	if (MTK_IOMMU_HAS_FLAG(data->plat_data, WR_THROT_EN)) {
 		/* write command throttling mode */
 		regval = readl_relaxed(data->base + REG_MMU_WR_LEN_CTRL);