[PATCH 04/12] irqchip: nvic: support routable irq domain ops

[stefan@agner.ch (Stefan Agner)]

Add support for routable irq domain ops like the GIC interrupt
controller provides. This is useful for asymmetrical multi-
processor SoCs, such as Freescale Vybrid (VF6xx) which have
a Cortex-M4 alongside a Cortex-A5 and a interrupt router to
route the peripheral interrupts between them.

Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 drivers/irqchip/irq-nvic.c       | 70 +++++++++++++++++++++++++++++++++++++++-
 include/linux/irqchip/arm-nvic.h | 25 ++++++++++++++
 2 files changed, 94 insertions(+), 1 deletion(-)
 create mode 100644 include/linux/irqchip/arm-nvic.h

diff --git a/drivers/irqchip/irq-nvic.c b/drivers/irqchip/irq-nvic.c
index 4ff0805..dbfb5be 100644
--- a/drivers/irqchip/irq-nvic.c
+++ b/drivers/irqchip/irq-nvic.c
@@ -40,6 +40,7 @@
 #define NVIC_MAX_IRQ		((NVIC_MAX_BANKS - 1) * 32 + 16)
 
 static struct irq_domain *nvic_irq_domain;
+const struct irq_domain_ops *nvic_routable_irq_domain_ops;
 
 asmlinkage void __exception_irq_entry
 nvic_handle_irq(irq_hw_number_t hwirq, struct pt_regs *regs)
@@ -49,6 +50,73 @@ nvic_handle_irq(irq_hw_number_t hwirq, struct pt_regs *regs)
 	handle_IRQ(irq, regs);
 }
 
+static int nvic_irq_domain_map(struct irq_domain *d, unsigned int irq,
+				irq_hw_number_t hw)
+{
+	int ret;
+
+	ret = irq_map_generic_chip(d, irq, hw);
+
+	if (IS_ERR_VALUE(ret))
+		return ret;
+
+	return nvic_routable_irq_domain_ops->map(d, irq, hw);
+}
+
+static void nvic_irq_domain_unmap(struct irq_domain *d, unsigned int irq)
+{
+	nvic_routable_irq_domain_ops->unmap(d, irq);
+}
+
+static int nvic_irq_domain_xlate(struct irq_domain *d,
+				 struct device_node *controller,
+				 const u32 *intspec, unsigned int intsize,
+				 unsigned long *out_hwirq,
+				 unsigned int *out_type)
+{
+	*out_hwirq = intspec[0];
+	*out_type = IRQ_TYPE_NONE;
+
+	return nvic_routable_irq_domain_ops->xlate(d, controller, intspec,
+						  intsize, out_hwirq, out_type);
+}
+
+struct irq_domain_ops nvic_irq_domain_ops = {
+	.map	= nvic_irq_domain_map,
+	.unmap	= nvic_irq_domain_unmap,
+	.xlate	= nvic_irq_domain_xlate,
+};
+
+/* Default functions for routable irq domain */
+static int nvic_routable_irq_domain_map(struct irq_domain *d, unsigned int irq,
+			      irq_hw_number_t hw)
+{
+	return 0;
+}
+
+static void nvic_routable_irq_domain_unmap(struct irq_domain *d,
+					  unsigned int irq)
+{
+}
+
+static int nvic_routable_irq_domain_xlate(struct irq_domain *d,
+				struct device_node *controller,
+				const u32 *intspec, unsigned int intsize,
+				unsigned long *out_hwirq,
+				unsigned int *out_type)
+{
+	return 0;
+}
+
+static const struct irq_domain_ops nvic_default_routable_irq_domain_ops = {
+	.map = nvic_routable_irq_domain_map,
+	.unmap = nvic_routable_irq_domain_unmap,
+	.xlate = nvic_routable_irq_domain_xlate,
+};
+
+const struct irq_domain_ops *nvic_routable_irq_domain_ops =
+					&nvic_default_routable_irq_domain_ops;
+
 static int __init nvic_of_init(struct device_node *node,
 			       struct device_node *parent)
 {
@@ -70,7 +138,7 @@ static int __init nvic_of_init(struct device_node *node,
 		irqs = NVIC_MAX_IRQ;
 
 	nvic_irq_domain =
-		irq_domain_add_linear(node, irqs, &irq_generic_chip_ops, NULL);
+		irq_domain_add_linear(node, irqs, &nvic_irq_domain_ops, NULL);
 	if (!nvic_irq_domain) {
 		pr_warn("Failed to allocate irq domain\n");
 		return -ENOMEM;
diff --git a/include/linux/irqchip/arm-nvic.h b/include/linux/irqchip/arm-nvic.h
new file mode 100644
index 0000000..0e92a14
--- /dev/null
+++ b/include/linux/irqchip/arm-nvic.h
@@ -0,0 +1,25 @@
+/*
+ *  include/linux/irqchip/arm-nvic.h
+ *
+ *  Copyright (C) 2014 Stefan Agner
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __LINUX_IRQCHIP_ARM_NVIC_H
+#define __LINUX_IRQCHIP_ARM_NVIC_H
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_ARM_NVIC
+extern const struct irq_domain_ops *nvic_routable_irq_domain_ops;
+static inline void __init register_routable_domain_ops
+					(const struct irq_domain_ops *ops)
+{
+		nvic_routable_irq_domain_ops = ops;
+}
+#endif /* CONFIG_ARM_NVIC */
+
+#endif /* __ASSEMBLY__ */
+#endif /* __LINUX_IRQCHIP_ARM_NVIC_H */
-- 
2.1.3