irqchip/gic-v3: Refactor gic_of_init() for GICv3 driver

Isolate hardware abstraction (FDT) code to gic_of_init().
Rest of the logic goes to gic_init_bases() and expects well
defined data to initialize GIC properly. The same solution
is used for GICv2 driver.

This is needed for ACPI initialization later.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index d7be6dd..31205c7 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -811,17 +811,88 @@
 #endif
 }
 
+static int __init gic_init_bases(void __iomem *dist_base,
+				 struct redist_region *rdist_regs,
+				 u32 nr_redist_regions,
+				 u64 redist_stride,
+				 struct fwnode_handle *handle)
+{
+	struct device_node *node;
+	u32 typer;
+	int gic_irqs;
+	int err;
+
+	if (!is_hyp_mode_available())
+		static_key_slow_dec(&supports_deactivate);
+
+	if (static_key_true(&supports_deactivate))
+		pr_info("GIC: Using split EOI/Deactivate mode\n");
+
+	gic_data.dist_base = dist_base;
+	gic_data.redist_regions = rdist_regs;
+	gic_data.nr_redist_regions = nr_redist_regions;
+	gic_data.redist_stride = redist_stride;
+
+	gicv3_enable_quirks();
+
+	/*
+	 * Find out how many interrupts are supported.
+	 * The GIC only supports up to 1020 interrupt sources (SGI+PPI+SPI)
+	 */
+	typer = readl_relaxed(gic_data.dist_base + GICD_TYPER);
+	gic_data.rdists.id_bits = GICD_TYPER_ID_BITS(typer);
+	gic_irqs = GICD_TYPER_IRQS(typer);
+	if (gic_irqs > 1020)
+		gic_irqs = 1020;
+	gic_data.irq_nr = gic_irqs;
+
+	gic_data.domain = irq_domain_create_tree(handle, &gic_irq_domain_ops,
+						 &gic_data);
+	gic_data.rdists.rdist = alloc_percpu(typeof(*gic_data.rdists.rdist));
+
+	if (WARN_ON(!gic_data.domain) || WARN_ON(!gic_data.rdists.rdist)) {
+		err = -ENOMEM;
+		goto out_free;
+	}
+
+	set_handle_irq(gic_handle_irq);
+
+	node = to_of_node(handle);
+	if (IS_ENABLED(CONFIG_ARM_GIC_V3_ITS) && gic_dist_supports_lpis() &&
+	    node) /* Temp hack to prevent ITS init for ACPI */
+		its_init(node, &gic_data.rdists, gic_data.domain);
+
+	gic_smp_init();
+	gic_dist_init();
+	gic_cpu_init();
+	gic_cpu_pm_init();
+
+	return 0;
+
+out_free:
+	if (gic_data.domain)
+		irq_domain_remove(gic_data.domain);
+	free_percpu(gic_data.rdists.rdist);
+	return err;
+}
+
+static int __init gic_validate_dist_version(void __iomem *dist_base)
+{
+	u32 reg = readl_relaxed(dist_base + GICD_PIDR2) & GIC_PIDR2_ARCH_MASK;
+
+	if (reg != GIC_PIDR2_ARCH_GICv3 && reg != GIC_PIDR2_ARCH_GICv4)
+		return -ENODEV;
+
+	return 0;
+}
+
 static int __init gic_of_init(struct device_node *node, struct device_node *parent)
 {
 	void __iomem *dist_base;
 	struct redist_region *rdist_regs;
 	u64 redist_stride;
 	u32 nr_redist_regions;
-	u32 typer;
-	u32 reg;
-	int gic_irqs;
-	int err;
-	int i;
+	int err, i;
 
 	dist_base = of_iomap(node, 0);
 	if (!dist_base) {
@@ -830,11 +901,10 @@
 		return -ENXIO;
 	}
 
-	reg = readl_relaxed(dist_base + GICD_PIDR2) & GIC_PIDR2_ARCH_MASK;
-	if (reg != GIC_PIDR2_ARCH_GICv3 && reg != GIC_PIDR2_ARCH_GICv4) {
+	err = gic_validate_dist_version(dist_base);
+	if (err) {
 		pr_err("%s: no distributor detected, giving up\n",
 			node->full_name);
-		err = -ENODEV;
 		goto out_unmap_dist;
 	}
 
@@ -865,55 +935,11 @@
 	if (of_property_read_u64(node, "redistributor-stride", &redist_stride))
 		redist_stride = 0;
 
-	if (!is_hyp_mode_available())
-		static_key_slow_dec(&supports_deactivate);
+	err = gic_init_bases(dist_base, rdist_regs, nr_redist_regions,
+			     redist_stride, &node->fwnode);
+	if (!err)
+		return 0;
 
-	if (static_key_true(&supports_deactivate))
-		pr_info("GIC: Using split EOI/Deactivate mode\n");
-
-	gic_data.dist_base = dist_base;
-	gic_data.redist_regions = rdist_regs;
-	gic_data.nr_redist_regions = nr_redist_regions;
-	gic_data.redist_stride = redist_stride;
-
-	gicv3_enable_quirks();
-
-	/*
-	 * Find out how many interrupts are supported.
-	 * The GIC only supports up to 1020 interrupt sources (SGI+PPI+SPI)
-	 */
-	typer = readl_relaxed(gic_data.dist_base + GICD_TYPER);
-	gic_data.rdists.id_bits = GICD_TYPER_ID_BITS(typer);
-	gic_irqs = GICD_TYPER_IRQS(typer);
-	if (gic_irqs > 1020)
-		gic_irqs = 1020;
-	gic_data.irq_nr = gic_irqs;
-
-	gic_data.domain = irq_domain_add_tree(node, &gic_irq_domain_ops,
-					      &gic_data);
-	gic_data.rdists.rdist = alloc_percpu(typeof(*gic_data.rdists.rdist));
-
-	if (WARN_ON(!gic_data.domain) || WARN_ON(!gic_data.rdists.rdist)) {
-		err = -ENOMEM;
-		goto out_free;
-	}
-
-	set_handle_irq(gic_handle_irq);
-
-	if (IS_ENABLED(CONFIG_ARM_GIC_V3_ITS) && gic_dist_supports_lpis())
-		its_init(node, &gic_data.rdists, gic_data.domain);
-
-	gic_smp_init();
-	gic_dist_init();
-	gic_cpu_init();
-	gic_cpu_pm_init();
-
-	return 0;
-
-out_free:
-	if (gic_data.domain)
-		irq_domain_remove(gic_data.domain);
-	free_percpu(gic_data.rdists.rdist);
 out_unmap_rdist:
 	for (i = 0; i < nr_redist_regions; i++)
 		if (rdist_regs[i].redist_base)