1 files changed, 27 insertions, 16 deletions

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 1406e1f..d777d7e 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -2381,10 +2381,10 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
 	return 0;
 }
 
-static int arm_smmu_device_probe(struct arm_smmu_device *smmu)
+static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
 {
 	u32 reg;
-	bool coherent;
+	bool coherent = smmu->features & ARM_SMMU_FEAT_COHERENCY;
 
 	/* IDR0 */
 	reg = readl_relaxed(smmu->base + ARM_SMMU_IDR0);
@@ -2436,13 +2436,9 @@ static int arm_smmu_device_probe(struct arm_smmu_device *smmu)
 		smmu->features |= ARM_SMMU_FEAT_HYP;
 
 	/*
-	 * The dma-coherent property is used in preference to the ID
+	 * The coherency feature as set by FW is used in preference to the ID
 	 * register, but warn on mismatch.
 	 */
-	coherent = of_dma_is_coherent(smmu->dev->of_node);
-	if (coherent)
-		smmu->features |= ARM_SMMU_FEAT_COHERENCY;
-
 	if (!!(reg & IDR0_COHACC) != coherent)
 		dev_warn(smmu->dev, "IDR0.COHACC overridden by dma-coherent property (%s)\n",
 			 coherent ? "true" : "false");
@@ -2563,21 +2559,35 @@ static int arm_smmu_device_probe(struct arm_smmu_device *smmu)
 	return 0;
 }
 
-static int arm_smmu_device_dt_probe(struct platform_device *pdev)
+static int arm_smmu_device_dt_probe(struct platform_device *pdev,
+				    struct arm_smmu_device *smmu)
 {
-	int irq, ret;
-	struct resource *res;
-	struct arm_smmu_device *smmu;
 	struct device *dev = &pdev->dev;
-	bool bypass = true;
 	u32 cells;
+	int ret = -EINVAL;
 
 	if (of_property_read_u32(dev->of_node, "#iommu-cells", &cells))
 		dev_err(dev, "missing #iommu-cells property\n");
 	else if (cells != 1)
 		dev_err(dev, "invalid #iommu-cells value (%d)\n", cells);
 	else
-		bypass = false;
+		ret = 0;
+
+	parse_driver_options(smmu);
+
+	if (of_dma_is_coherent(dev->of_node))
+		smmu->features |= ARM_SMMU_FEAT_COHERENCY;
+
+	return ret;
+}
+
+static int arm_smmu_device_probe(struct platform_device *pdev)
+{
+	int irq, ret;
+	struct resource *res;
+	struct arm_smmu_device *smmu;
+	struct device *dev = &pdev->dev;
+	bool bypass;
 
 	smmu = devm_kzalloc(dev, sizeof(*smmu), GFP_KERNEL);
 	if (!smmu) {
@@ -2614,10 +2624,11 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev)
 	if (irq > 0)
 		smmu->gerr_irq = irq;
 
-	parse_driver_options(smmu);
+	/* Set bypass mode according to firmware probing result */
+	bypass = !!arm_smmu_device_dt_probe(pdev, smmu);
 
 	/* Probe the h/w */
-	ret = arm_smmu_device_probe(smmu);
+	ret = arm_smmu_device_hw_probe(smmu);
 	if (ret)
 		return ret;
 
@@ -2679,7 +2690,7 @@ static struct platform_driver arm_smmu_driver = {
 		.name		= "arm-smmu-v3",
 		.of_match_table	= of_match_ptr(arm_smmu_of_match),
 	},
-	.probe	= arm_smmu_device_dt_probe,
+	.probe	= arm_smmu_device_probe,
 	.remove	= arm_smmu_device_remove,
 };