ACPI/IORT: Add SMMUv3 specific special index mapping handling

IORT revision C introduced a mapping entry binding to describe ITS
device ID mapping for SMMUv3 MSI interrupts.

Enable the single mapping flag (ie that is used by SMMUv3 component for
its special index mappings) for the SMMUv3 node in the IORT mapping API
and add IORT code to handle special index mapping entry for the SMMUv3
IORT nodes to enable their MSI interrupts. In case the ACPICA for
SMMUv3 device ID mapping is not ready, use the ACPICA version as a guard
for function iort_get_id_mapping_index().
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
[lorenzo.pieralisi@arm.com: patch split, typos fixing, rewrote the log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

drivers/acpi/arm64/iort.c

@@ -356,7 +356,8 @@ static struct acpi_iort_node *iort_node_get_id(struct acpi_iort_node *node,
 
 	if (map->flags & ACPI_IORT_ID_SINGLE_MAPPING) {
 		if (node->type == ACPI_IORT_NODE_NAMED_COMPONENT ||
-		    node->type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX) {
+		    node->type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX ||
+		    node->type == ACPI_IORT_NODE_SMMU_V3) {
 			*id_out = map->output_base;
 			return parent;
 		}
@@ -365,10 +366,46 @@ static struct acpi_iort_node *iort_node_get_id(struct acpi_iort_node *node,
 	return NULL;
 }
 
+#if (ACPI_CA_VERSION > 0x20170929)
+static int iort_get_id_mapping_index(struct acpi_iort_node *node)
+{
+	struct acpi_iort_smmu_v3 *smmu;
+
+	switch (node->type) {
+	case ACPI_IORT_NODE_SMMU_V3:
+		/*
+		 * SMMUv3 dev ID mapping index was introduced in revision 1
+		 * table, not available in revision 0
+		 */
+		if (node->revision < 1)
+			return -EINVAL;
+
+		smmu = (struct acpi_iort_smmu_v3 *)node->node_data;
+		/*
+		 * ID mapping index is only ignored if all interrupts are
+		 * GSIV based
+		 */
+		if (smmu->event_gsiv && smmu->pri_gsiv && smmu->gerr_gsiv
+		    && smmu->sync_gsiv)
+			return -EINVAL;
+
+		if (smmu->id_mapping_index >= node->mapping_count) {
+			pr_err(FW_BUG "[node %p type %d] ID mapping index overflows valid mappings\n",
+			       node, node->type);
+			return -EINVAL;
+		}
+
+		return smmu->id_mapping_index;
+	default:
+		return -EINVAL;
+	}
+}
+#else
 static inline int iort_get_id_mapping_index(struct acpi_iort_node *node)
 {
 	return -EINVAL;
 }
+#endif
 
 static struct acpi_iort_node *iort_node_map_id(struct acpi_iort_node *node,
 					       u32 id_in, u32 *id_out,