acpi: Conditionally set mapping_offset in IORT

The spec recommends to set the mapping_offset only when there are
ID mappings as indicated by the mapping_count field.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>

diff --git a/lib/acpi/acpi_table.c b/lib/acpi/acpi_table.c
index fc43862..4ad1f56 100644 (file)
--- a/lib/acpi/acpi_table.c
+++ b/lib/acpi/acpi_table.c
@@ -649,7 +649,9 @@ int acpi_iort_add_rc(struct acpi_ctx *ctx,
        node->type = ACPI_IORT_NODE_PCI_ROOT_COMPLEX;
        node->revision = 2;
        node->mapping_count = num_mappings;
-       node->mapping_offset = sizeof(struct acpi_iort_node) + sizeof(struct acpi_iort_rc);
+       if (num_mappings)
+               node->mapping_offset = sizeof(struct acpi_iort_node) +
+                                      sizeof(struct acpi_iort_rc);
 
        node->length = sizeof(struct acpi_iort_node);
        node->length += sizeof(struct acpi_iort_rc);
@@ -709,7 +711,9 @@ int acpi_iort_add_smmu_v3(struct acpi_ctx *ctx,
        node->type = ACPI_IORT_NODE_SMMU_V3;
        node->revision = 5;
        node->mapping_count = num_mappings;
-       node->mapping_offset = sizeof(struct acpi_iort_node) + sizeof(struct acpi_iort_smmu_v3);
+       if (num_mappings)
+               node->mapping_offset = sizeof(struct acpi_iort_node) +
+                                      sizeof(struct acpi_iort_smmu_v3);
 
        node->length = sizeof(struct acpi_iort_node);
        node->length += sizeof(struct acpi_iort_smmu_v3);