irqchip/gic-v3-its: Add ACPI NUMA node mapping

Add code to parse SRAT ITS Affinity sub table as defined in ACPI 6.2.
Later in per device probe, ITS devices are mapped to numa node using
ITS Id to proximity domain mapping.

[maz: fix dependency on ACPICA, fixed structure name, minor cleanups]

Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/irq-gic-v3-its.c

@@ -1836,6 +1836,78 @@ static int __init its_of_probe(struct device_node *node)
 
 #define ACPI_GICV3_ITS_MEM_SIZE (SZ_128K)
 
+#if defined(CONFIG_ACPI_NUMA) && (ACPI_CA_VERSION >= 0x20170531)
+struct its_srat_map {
+	/* numa node id */
+	u32	numa_node;
+	/* GIC ITS ID */
+	u32	its_id;
+};
+
+static struct its_srat_map its_srat_maps[MAX_NUMNODES] __initdata;
+static int its_in_srat __initdata;
+
+static int __init acpi_get_its_numa_node(u32 its_id)
+{
+	int i;
+
+	for (i = 0; i < its_in_srat; i++) {
+		if (its_id == its_srat_maps[i].its_id)
+			return its_srat_maps[i].numa_node;
+	}
+	return NUMA_NO_NODE;
+}
+
+static int __init gic_acpi_parse_srat_its(struct acpi_subtable_header *header,
+			 const unsigned long end)
+{
+	int node;
+	struct acpi_srat_gic_its_affinity *its_affinity;
+
+	its_affinity = (struct acpi_srat_gic_its_affinity *)header;
+	if (!its_affinity)
+		return -EINVAL;
+
+	if (its_affinity->header.length < sizeof(*its_affinity)) {
+		pr_err("SRAT: Invalid header length %d in ITS affinity\n",
+			its_affinity->header.length);
+		return -EINVAL;
+	}
+
+	if (its_in_srat >= MAX_NUMNODES) {
+		pr_err("SRAT: ITS affinity exceeding max count[%d]\n",
+				MAX_NUMNODES);
+		return -EINVAL;
+	}
+
+	node = acpi_map_pxm_to_node(its_affinity->proximity_domain);
+
+	if (node == NUMA_NO_NODE || node >= MAX_NUMNODES) {
+		pr_err("SRAT: Invalid NUMA node %d in ITS affinity\n", node);
+		return 0;
+	}
+
+	its_srat_maps[its_in_srat].numa_node = node;
+	its_srat_maps[its_in_srat].its_id = its_affinity->its_id;
+	its_in_srat++;
+	pr_info("SRAT: PXM %d -> ITS %d -> Node %d\n",
+		its_affinity->proximity_domain, its_affinity->its_id, node);
+
+	return 0;
+}
+
+static void __init acpi_table_parse_srat_its(void)
+{
+	acpi_table_parse_entries(ACPI_SIG_SRAT,
+			sizeof(struct acpi_table_srat),
+			ACPI_SRAT_TYPE_GIC_ITS_AFFINITY,
+			gic_acpi_parse_srat_its, 0);
+}
+#else
+static void __init acpi_table_parse_srat_its(void)	{ }
+static int __init acpi_get_its_numa_node(u32 its_id) { return NUMA_NO_NODE; }
+#endif
+
 static int __init gic_acpi_parse_madt_its(struct acpi_subtable_header *header,
 					  const unsigned long end)
 {
@@ -1864,7 +1936,8 @@ static int __init gic_acpi_parse_madt_its(struct acpi_subtable_header *header,
 		goto dom_err;
 	}
 
-	err = its_probe_one(&res, dom_handle, NUMA_NO_NODE);
+	err = its_probe_one(&res, dom_handle,
+			acpi_get_its_numa_node(its_entry->translation_id));
 	if (!err)
 		return 0;
 
@@ -1876,6 +1949,7 @@ dom_err:
 
 static void __init its_acpi_probe(void)
 {
+	acpi_table_parse_srat_its();
 	acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
 			      gic_acpi_parse_madt_its, 0);
 }