irqchip/gic-v4: Enable low-level GICv4 operations

Get the show on the road...
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/Makefile

@@ -28,7 +28,7 @@ obj-$(CONFIG_ARM_GIC_PM)		+= irq-gic-pm.o
 obj-$(CONFIG_ARCH_REALVIEW)		+= irq-gic-realview.o
 obj-$(CONFIG_ARM_GIC_V2M)		+= irq-gic-v2m.o
 obj-$(CONFIG_ARM_GIC_V3)		+= irq-gic-v3.o irq-gic-common.o
-obj-$(CONFIG_ARM_GIC_V3_ITS)		+= irq-gic-v3-its.o irq-gic-v3-its-pci-msi.o irq-gic-v3-its-platform-msi.o
+obj-$(CONFIG_ARM_GIC_V3_ITS)		+= irq-gic-v3-its.o irq-gic-v3-its-pci-msi.o irq-gic-v3-its-platform-msi.o irq-gic-v4.o
 obj-$(CONFIG_PARTITION_PERCPU)		+= irq-partition-percpu.o
 obj-$(CONFIG_HISILICON_IRQ_MBIGEN)	+= irq-mbigen.o
 obj-$(CONFIG_ARM_NVIC)			+= irq-nvic.o

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

@@ -3226,7 +3226,8 @@ int __init its_init(struct fwnode_handle *handle, struct rdists *rdists,
 		has_v4 |= its->is_v4;
 
 	if (has_v4 & rdists->has_vlpis) {
-		if (its_init_vpe_domain()) {
+		if (its_init_vpe_domain() ||
+		    its_init_v4(parent_domain, &its_vpe_domain_ops)) {
 			rdists->has_vlpis = false;
 			pr_err("ITS: Disabling GICv4 support\n");
 		}

drivers/irqchip/irq-gic-v4.c

@@ -210,3 +210,16 @@ int its_prop_update_vlpi(int irq, u8 config, bool inv)
 
 	return irq_set_vcpu_affinity(irq, &info);
 }
+
+int its_init_v4(struct irq_domain *domain, const struct irq_domain_ops *ops)
+{
+	if (domain) {
+		pr_info("ITS: Enabling GICv4 support\n");
+		gic_domain = domain;
+		vpe_domain_ops = ops;
+		return 0;
+	}
+
+	pr_err("ITS: No GICv4 VPE domain allocated\n");
+	return -ENODEV;
+}

include/linux/irqchip/arm-gic-v4.h

@@ -100,4 +100,6 @@ int its_get_vlpi(int irq, struct its_vlpi_map *map);
 int its_unmap_vlpi(int irq);
 int its_prop_update_vlpi(int irq, u8 config, bool inv);
 
+int its_init_v4(struct irq_domain *domain, const struct irq_domain_ops *ops);
+
 #endif