MIPS: JZ4740: support >32 interrupts

On newer Ingenic SoCs the interrupt controller supports more than 32
interrupts, which it does by duplicating the registers at intervals
of 0x20 bytes within its address space. Add support for an arbitrary
number of interrupts using multiple generic chips, and provide the
number of chips to register from the interrupt controller probe
function.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: Brian Norris <computersforpeace@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/10141/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/jz4740/irq.c

@@ -34,6 +34,7 @@
 
 struct ingenic_intc_data {
 	void __iomem *base;
+	unsigned num_chips;
 };
 
 #define JZ_REG_INTC_STATUS	0x00
@@ -41,16 +42,22 @@ struct ingenic_intc_data {
 #define JZ_REG_INTC_SET_MASK	0x08
 #define JZ_REG_INTC_CLEAR_MASK	0x0c
 #define JZ_REG_INTC_PENDING	0x10
+#define CHIP_SIZE		0x20
 
 static irqreturn_t jz4740_cascade(int irq, void *data)
 {
 	struct ingenic_intc_data *intc = irq_get_handler_data(irq);
 	uint32_t irq_reg;
+	unsigned i;
 
-	irq_reg = readl(intc->base + JZ_REG_INTC_PENDING);
+	for (i = 0; i < intc->num_chips; i++) {
+		irq_reg = readl(intc->base + (i * CHIP_SIZE) +
+				JZ_REG_INTC_PENDING);
+		if (!irq_reg)
+			continue;
 
-	if (irq_reg)
-		generic_handle_irq(__fls(irq_reg) + JZ4740_IRQ_BASE);
+		generic_handle_irq(__fls(irq_reg) + (i * 32) + JZ4740_IRQ_BASE);
+	}
 
 	return IRQ_HANDLED;
 }
@@ -80,14 +87,15 @@ static struct irqaction jz4740_cascade_action = {
 	.name = "JZ4740 cascade interrupt",
 };
 
-static int __init jz4740_intc_of_init(struct device_node *node,
-	struct device_node *parent)
+static int __init ingenic_intc_of_init(struct device_node *node,
+				       unsigned num_chips)
 {
 	struct ingenic_intc_data *intc;
 	struct irq_chip_generic *gc;
 	struct irq_chip_type *ct;
 	struct irq_domain *domain;
 	int parent_irq, err = 0;
+	unsigned i;
 
 	intc = kzalloc(sizeof(*intc), GFP_KERNEL);
 	if (!intc) {
@@ -105,12 +113,17 @@ static int __init jz4740_intc_of_init(struct device_node *node,
 	if (err)
 		goto out_unmap_irq;
 
+	intc->num_chips = num_chips;
 	intc->base = ioremap(JZ4740_INTC_BASE_ADDR, 0x14);
 
+	for (i = 0; i < num_chips; i++) {
 		/* Mask all irqs */
-	writel(0xffffffff, intc->base + JZ_REG_INTC_SET_MASK);
+		writel(0xffffffff, intc->base + (i * CHIP_SIZE) +
+		       JZ_REG_INTC_SET_MASK);
 
-	gc = irq_alloc_generic_chip("INTC", 1, JZ4740_IRQ_BASE, intc->base,
+		gc = irq_alloc_generic_chip("INTC", 1,
+					    JZ4740_IRQ_BASE + (i * 32),
+					    intc->base + (i * CHIP_SIZE),
 					    handle_level_irq);
 
 		gc->wake_enabled = IRQ_MSK(32);
@@ -125,7 +138,9 @@ static int __init jz4740_intc_of_init(struct device_node *node,
 		ct->chip.irq_suspend = jz4740_irq_suspend;
 		ct->chip.irq_resume = jz4740_irq_resume;
 
-	irq_setup_generic_chip(gc, IRQ_MSK(32), 0, 0, IRQ_NOPROBE | IRQ_LEVEL);
+		irq_setup_generic_chip(gc, IRQ_MSK(32), 0, 0,
+				       IRQ_NOPROBE | IRQ_LEVEL);
+	}
 
 	domain = irq_domain_add_legacy(node, num_chips * 32, JZ4740_IRQ_BASE, 0,
 				       &irq_domain_simple_ops, NULL);
@@ -142,4 +157,10 @@ static int __init jz4740_intc_of_init(struct device_node *node,
 out_err:
 	return err;
 }
-IRQCHIP_DECLARE(jz4740_intc, "ingenic,jz4740-intc", jz4740_intc_of_init);
+
+static int __init intc_1chip_of_init(struct device_node *node,
+				     struct device_node *parent)
+{
+	return ingenic_intc_of_init(node, 1);
+}
+IRQCHIP_DECLARE(jz4740_intc, "ingenic,jz4740-intc", intc_1chip_of_init);