ARM: Exynos: Add irq domain and device tree support for interrupt combiner

diff --git a/Documentation/devicetree/bindings/arm/samsung/interrupt-combiner.txt b/Documentation/devicetree/bindings/arm/samsung/interrupt-combiner.txt
new file mode 100644
index 0000000..6ca30d9
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/samsung/interrupt-combiner.txt
@@ -0,0 +1,18 @@ 
+* Samsung Exynos Interrupt Combiner Controller
+
+Samsung's Exynos4 architecture includes a interrupt combiner which can combine
+interrupt sources as a group and provide a single interrupt request for the
+group. The interrupt request from each group are connected to a parent interrupt
+controller, such as GIC in case of Exynos4210.
+
+Required properties:
+- compatible: should be "samsung,exynos4210-combiner".
+- #interrupt-cells: should be <2>. The meaning of the cells are
+	* First Cell: Combiner Group Number.
+	* Second Cell: Interrupt number within the group.
+- reg: Base address and size of interrupt combiner registers.
+- interrupt-controller: Identifies the node as an interrupt controller.
+
+Optional properties:
+- interrupt-parent: pHandle of the parent interrupt controller, if not
+  inherited from the parent node.
diff --git a/arch/arm/mach-exynos/cpu.c b/arch/arm/mach-exynos/cpu.c
index 8e09f34..14f86ba 100644
--- a/arch/arm/mach-exynos/cpu.c
+++ b/arch/arm/mach-exynos/cpu.c
@@ -37,9 +37,10 @@ 
 
 unsigned int gic_bank_offset __read_mostly;
 
-extern int combiner_init(unsigned int combiner_nr, void __iomem *base,
-			 unsigned int irq_start);
+extern int combiner_init(unsigned int combiner_nr, void __iomem *base);
 extern void combiner_cascade_irq(unsigned int combiner_nr, unsigned int irq);
+extern int combiner_init_irq_domain(unsigned int irq_base, unsigned int nr_irq,
+					struct device_node *np);
 
 /* Initial IO mappings */
 static struct map_desc exynos_iodesc[] __initdata = {
@@ -242,16 +243,30 @@  static void exynos4_gic_irq_fix_base(struct irq_data *d)
 			    (gic_bank_offset * smp_processor_id());
 }
 
+void __init combiner_of_init(struct device_node *np, struct device_node *parent)
+{
+	int irq;
+
+	if (combiner_init_irq_domain(COMBINER_IRQ(0, 0), MAX_COMBINER_NR *
+					MAX_IRQ_IN_COMBINER, np))
+		BUG();
+	for (irq = 0; irq < MAX_COMBINER_NR; irq++) {
+		combiner_init(irq, (void __iomem *)S5P_VA_COMBINER(irq));
+		combiner_cascade_irq(irq, IRQ_SPI(irq));
+	}
+}
+
 #ifdef CONFIG_OF
 static const struct of_device_id exynos4_dt_irq_match[] = {
 	{ .compatible = "arm,cortex-a9-gic", .data = gic_of_init, },
+	{ .compatible = "samsung,exynos4120-combiner",
+			.data = combiner_of_init, },
 	{},
 };
 #endif
 
 void __init exynos4_init_irq(void)
 {
-	int irq;
 
 	gic_bank_offset = soc_is_exynos4412() ? 0x4000 : 0x8000;
 
@@ -266,12 +281,8 @@  void __init exynos4_init_irq(void)
 	gic_arch_extn.irq_unmask = exynos4_gic_irq_fix_base;
 	gic_arch_extn.irq_mask = exynos4_gic_irq_fix_base;
 
-	for (irq = 0; irq < MAX_COMBINER_NR; irq++) {
-
-		combiner_init(irq, (void __iomem *)S5P_VA_COMBINER(irq),
-				COMBINER_IRQ(irq, 0));
-		combiner_cascade_irq(irq, IRQ_SPI(irq));
-	}
+	if (!of_have_populated_dt())
+		combiner_of_init(NULL, NULL);
 
 	/* The parameters of s5p_init_irq() are for VIC init.
 	 * Theses parameters should be NULL and 0 because EXYNOS4
diff --git a/arch/arm/mach-exynos/irq-combiner.c b/arch/arm/mach-exynos/irq-combiner.c
index 5a2758a..84f24c9 100644
--- a/arch/arm/mach-exynos/irq-combiner.c
+++ b/arch/arm/mach-exynos/irq-combiner.c
@@ -13,6 +13,8 @@ 
 */
 
 #include <linux/io.h>
+#include <linux/export.h>
+#include <linux/irqdomain.h>
 
 #include <asm/mach/irq.h>
 
@@ -26,8 +28,10 @@  struct combiner_chip_data {
 	unsigned int irq_offset;
 	unsigned int irq_mask;
 	void __iomem *base;
+	struct irq_domain *domain;
 };
 
+static struct irq_domain combiner_irq_domain;
 static struct combiner_chip_data combiner_data[MAX_COMBINER_NR];
 
 static inline void __iomem *combiner_base(struct irq_data *data)
@@ -40,14 +44,14 @@  static inline void __iomem *combiner_base(struct irq_data *data)
 
 static void combiner_mask_irq(struct irq_data *data)
 {
-	u32 mask = 1 << (data->irq % 32);
+	u32 mask = 1 << (data->hwirq % 32);
 
 	__raw_writel(mask, combiner_base(data) + COMBINER_ENABLE_CLEAR);
 }
 
 static void combiner_unmask_irq(struct irq_data *data)
 {
-	u32 mask = 1 << (data->irq % 32);
+	u32 mask = 1 << (data->hwirq % 32);
 
 	__raw_writel(mask, combiner_base(data) + COMBINER_ENABLE_SET);
 }
@@ -96,17 +100,18 @@  void __init combiner_cascade_irq(unsigned int combiner_nr, unsigned int irq)
 	irq_set_chained_handler(irq, combiner_handle_cascade_irq);
 }
 
-void __init combiner_init(unsigned int combiner_nr, void __iomem *base,
-			  unsigned int irq_start)
+void __init combiner_init(unsigned int combiner_nr, void __iomem *base)
 {
-	unsigned int i;
+	unsigned int i, hwirq;
 
 	if (combiner_nr >= MAX_COMBINER_NR)
 		BUG();
 
 	combiner_data[combiner_nr].base = base;
-	combiner_data[combiner_nr].irq_offset = irq_start;
+	combiner_data[combiner_nr].irq_offset =	irq_domain_to_irq(
+		&combiner_irq_domain, combiner_nr * MAX_IRQ_IN_COMBINER);
 	combiner_data[combiner_nr].irq_mask = 0xff << ((combiner_nr % 4) << 3);
+	combiner_data[combiner_nr].domain = &combiner_irq_domain;
 
 	/* Disable all interrupts */
 
@@ -114,11 +119,46 @@  void __init combiner_init(unsigned int combiner_nr, void __iomem *base,
 		     base + COMBINER_ENABLE_CLEAR);
 
 	/* Setup the Linux IRQ subsystem */
-
-	for (i = irq_start; i < combiner_data[combiner_nr].irq_offset
-				+ MAX_IRQ_IN_COMBINER; i++) {
+	for (hwirq = 0; hwirq < MAX_IRQ_IN_COMBINER; hwirq++) {
+		i = combiner_data[combiner_nr].irq_offset + hwirq;
 		irq_set_chip_and_handler(i, &combiner_chip, handle_level_irq);
 		irq_set_chip_data(i, &combiner_data[combiner_nr]);
 		set_irq_flags(i, IRQF_VALID | IRQF_PROBE);
 	}
 }
+
+static int combiner_dt_translate(struct irq_domain *d,
+		struct device_node *controller, const u32 *intspec,
+		unsigned int intsize, unsigned long *out_hwirq,
+		unsigned int *out_type)
+{
+	if (d->of_node != controller)
+		return -EINVAL;
+	if (intsize < 2)
+		return -EINVAL;
+
+	*out_hwirq = intspec[0] * MAX_IRQ_IN_COMBINER + intspec[1];
+	*out_type = 0;
+	return 0;
+}
+
+static struct irq_domain_ops combiner_irq_domain_ops = {
+	.dt_translate = combiner_dt_translate,
+};
+
+int __init combiner_init_irq_domain(unsigned int irq_base, unsigned int nr_irq,
+					struct device_node *np)
+{
+	struct irq_domain *domain = &combiner_irq_domain;
+
+	domain->irq_base = irq_alloc_descs(irq_base, irq_base, nr_irq, 0);
+	if (domain->irq_base < 0) {
+		pr_err("failed to alloc irq descs, combiner init failed\n");
+		return -EBUSY;
+	}
+	domain->nr_irq = nr_irq;
+	domain->ops = &combiner_irq_domain_ops;
+	domain->of_node = np;
+	irq_domain_add(domain);
+	return 0;
+}