ACPI/IORT: Add function to check SMMUs drivers presence

The IOMMU probe deferral implementation requires a mechanism to detect
if drivers for SMMU components are built-in in the kernel to detect
whether IOMMU configuration for a given device should be deferred (ie
SMMU drivers present but still not probed) or not (drivers not present).

Add a simple function to IORT to detect if SMMU drivers for SMMU
components managed by IORT are built-in in the kernel.

Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Cc: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 4a5bb967250bc5ae66f7a6fbf64f26a3f0759571..3dd9ec372dae57218b1ca8f0b73026bb527b5197 100644 (file)
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -523,6 +523,19 @@ static int arm_smmu_iort_xlate(struct device *dev, u32 streamid,
        return ret;
 }
 
+static inline bool iort_iommu_driver_enabled(u8 type)
+{
+       switch (type) {
+       case ACPI_IORT_NODE_SMMU_V3:
+               return IS_BUILTIN(CONFIG_ARM_SMMU_V3);
+       case ACPI_IORT_NODE_SMMU:
+               return IS_BUILTIN(CONFIG_ARM_SMMU);
+       default:
+               pr_warn("IORT node type %u does not describe an SMMU\n", type);
+               return false;
+       }
+}
+
 static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
                                        struct acpi_iort_node *node,
                                        u32 streamid)