1 files changed, 215 insertions, 0 deletions
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
new file mode 100644
index 00000000000..7e251cd810b
--- /dev/null
+++ b/kernel/irq/irqdomain.c
@@ -0,0 +1,215 @@
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+
+static LIST_HEAD(irq_domain_list);
+static DEFINE_MUTEX(irq_domain_mutex);
+
+/**
+ * irq_domain_add() - Register an irq_domain
+ * @domain: ptr to initialized irq_domain structure
+ *
+ * Registers an irq_domain structure.  The irq_domain must at a minimum be
+ * initialized with an ops structure pointer, and either a ->to_irq hook or
+ * a valid irq_base value.  Everything else is optional.
+ */
+void irq_domain_add(struct irq_domain *domain)
+{
+	mutex_lock(&irq_domain_mutex);
+	list_add(&domain->list, &irq_domain_list);
+	mutex_unlock(&irq_domain_mutex);
+}
+
+/**
+ * irq_domain_del() - Unregister an irq_domain
+ * @domain: ptr to registered irq_domain.
+ */
+void irq_domain_del(struct irq_domain *domain)
+{
+	mutex_lock(&irq_domain_mutex);
+	list_del(&domain->list);
+	mutex_unlock(&irq_domain_mutex);
+}
+
+/**
+ * irq_domain_map() - Allocate and/or increment a reference to a hwirq
+ *
+ * TODO: Establish a linux irq number mapping for a hardware irq.  If the
+ * mapping already exists, then increment the reference count and return the
+ * linux irq number.
+ *
+ * At the moment this function is an empty stub since irq_domain initially
+ * only supports the common case of mapping hw irq numbers into a contiguous
+ * range of pre-allocated linux irq_descs based at irq_domain->irq_base.  When
+ * irq_domains are extended either to support non-contiguous mappings (ie. to
+ * support MSI interrupts) or to remove preallocation of all irq_descs (as
+ * powerpc does so that irq_descs are only allocated for in-use irq inputs),
+ * then this function will be extended to implement the irq_desc allocation
+ * and reference counting.
+ *
+ * Any caller to this function must arrange to also call irq_domain_unmap()
+ * if the irq ever becomes unused again.
+ */
+unsigned int irq_domain_map(struct irq_domain *domain, irq_hw_number_t hwirq)
+{
+	int irq = irq_domain_to_irq(domain, hwirq);
+	struct irq_data *d = irq_get_irq_data(irq);
+
+	d->domain = domain;
+	d->hwirq = hwirq;
+
+	return irq;
+}
+
+/**
+ * irq_domain_unmap() - Release a reference to a hwirq
+ *
+ * TODO: decrement the reference count on a hardware irq number.  If the ref
+ * count reaches zero, then the irq_desc can be freed.
+ *
+ * At the moment this function is an empty stub.  See the comment on
+ * irq_domain_map() for details.
+ */
+void irq_domain_unmap(struct irq_domain *domain, irq_hw_number_t hwirq)
+{
+	int irq = irq_domain_to_irq(domain, hwirq);
+	struct irq_data *d = irq_get_irq_data(irq);
+
+	d->domain = NULL;
+}
+
+#if defined(CONFIG_OF_IRQ) && !defined(CONFIG_PPC)
+
+/*
+ * A handful of architectures use NO_IRQ, which must be used to avoid breaking
+ * things when using the device tree.  This is intended to be temporary until
+ * the remaining NO_IRQ users can be removed
+ */
+#ifndef NO_IRQ
+#define NO_IRQ 0
+#endif
+
+/**
+ * irq_create_of_mapping() - Map a linux irq number from a DT interrupt spec
+ *
+ * Used by the device tree interrupt mapping code to translate a device tree
+ * interrupt specifier to a valid linux irq number.  Returns either a valid
+ * linux IRQ number or 0.
+ *
+ * When the caller no longer need the irq number returned by this function it
+ * should arrange to call irq_dispose_mapping().
+ */
+unsigned int irq_create_of_mapping(struct device_node *controller,
+				   const u32 *intspec, unsigned int intsize)
+{
+	struct irq_domain *domain;
+	irq_hw_number_t hwirq;
+	unsigned int irq, type;
+	int rc = -ENODEV;
+
+	/* Find a domain which can translate the irq spec */
+	mutex_lock(&irq_domain_mutex);
+	list_for_each_entry(domain, &irq_domain_list, list) {
+		if (!domain->ops->dt_translate)
+			continue;
+		rc = domain->ops->dt_translate(domain, controller,
+					intspec, intsize, &hwirq, &type);
+		if (rc == 0)
+			break;
+	}
+	mutex_unlock(&irq_domain_mutex);
+
+#if defined(CONFIG_MIPS) || defined(CONFIG_MICROBLAZE)
+	/*
+	 * Temporary: preserves current behaviour until mips/microblaze
+	 * register an irq_domain
+	 */
+	if (rc != 0) {
+		pr_debug("%s: fallback mapping for irq=%i\n",
+			 controller->full_name, irq);
+		return intspec[0];
+	}
+#else
+	if (rc != 0)
+		return NO_IRQ;
+#endif
+
+	irq = irq_domain_map(domain, hwirq);
+	if (type != IRQ_TYPE_NONE)
+		irq_set_irq_type(irq, type);
+	pr_debug("%s: mapped hwirq=%i to irq=%i, flags=%x\n",
+		 controller->full_name, (int)hwirq, irq, type);
+	return irq;
+}
+EXPORT_SYMBOL_GPL(irq_create_of_mapping);
+
+/**
+ * irq_dispose_mapping() - Discard a mapping created by irq_create_of_mapping()
+ * @irq: linux irq number to be discarded
+ *
+ * Calling this function indicates the caller no longer needs a reference to
+ * the linux irq number returned by a prior call to irq_create_of_mapping().
+ */
+void irq_dispose_mapping(unsigned int irq)
+{
+	struct irq_data *d = irq_get_irq_data(irq);
+	irq_domain_unmap(d->domain, d->hwirq);
+}
+EXPORT_SYMBOL_GPL(irq_dispose_mapping);
+
+int irq_domain_simple_dt_translate(struct irq_domain *d,
+			    struct device_node *controller,
+			    const u32 *intspec, unsigned int intsize,
+			    irq_hw_number_t *out_hwirq, unsigned int *out_type)
+{
+	if (d->of_node != controller)
+		return -EINVAL;
+	if (intsize != 1)
+		return -EINVAL;
+
+	*out_hwirq = intspec[0];
+	*out_type = IRQ_TYPE_NONE;
+	return 0;
+}
+
+struct irq_domain_ops irq_domain_simple_ops = {
+	.dt_translate = irq_domain_simple_dt_translate,
+};
+
+/**
+ * irq_domain_create_simple() - Set up a 'simple' translation range
+ */
+void irq_domain_add_simple(struct device_node *controller, int irq_base)
+{
+	struct irq_domain *domain;
+
+	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
+	if (!domain) {
+		WARN_ON(1);
+		return;
+	}
+
+	domain->irq_base = irq_base;
+	domain->of_node = of_node_get(controller);
+	domain->ops = &irq_domain_simple_ops;
+	irq_domain_add(domain);
+}
+EXPORT_SYMBOL_GPL(irq_domain_add_simple);
+
+void irq_domain_generate_simple(const struct of_device_id *match,
+				u64 phys_base, unsigned int irq_start)
+{
+	struct device_node *node;
+	pr_info("looking for phys_base=%llx, irq_start=%i\n",
+		(unsigned long long) phys_base, (int) irq_start);
+	node = of_find_matching_node_by_address(NULL, match, phys_base);
+	if (node)
+		irq_domain_add_simple(node, irq_start);
+	else
+		pr_info("no node found\n");
+}
+EXPORT_SYMBOL_GPL(irq_domain_generate_simple);
+#endif