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>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 4a5bb967250b..3dd9ec372dae 100644
--- 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)