1 files changed, 255 insertions, 0 deletions
diff --git a/drivers/sh/intc/virq.c b/drivers/sh/intc/virq.c
new file mode 100644
index 000000000000..643dfd4d2057
--- /dev/null
+++ b/drivers/sh/intc/virq.c
@@ -0,0 +1,255 @@
+/*
+ * Support for virtual IRQ subgroups.
+ *
+ * Copyright (C) 2010  Paul Mundt
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#define pr_fmt(fmt) "intc: " fmt
+
+#include <linux/slab.h>
+#include <linux/irq.h>
+#include <linux/list.h>
+#include <linux/radix-tree.h>
+#include <linux/spinlock.h>
+#include "internals.h"
+
+static struct intc_map_entry intc_irq_xlate[NR_IRQS];
+
+struct intc_virq_list {
+	unsigned int irq;
+	struct intc_virq_list *next;
+};
+
+#define for_each_virq(entry, head) \
+	for (entry = head; entry; entry = entry->next)
+
+/*
+ * Tags for the radix tree
+ */
+#define INTC_TAG_VIRQ_NEEDS_ALLOC	0
+
+void intc_irq_xlate_set(unsigned int irq, intc_enum id, struct intc_desc_int *d)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&intc_big_lock, flags);
+	intc_irq_xlate[irq].enum_id = id;
+	intc_irq_xlate[irq].desc = d;
+	raw_spin_unlock_irqrestore(&intc_big_lock, flags);
+}
+
+struct intc_map_entry *intc_irq_xlate_get(unsigned int irq)
+{
+	return intc_irq_xlate + irq;
+}
+
+int intc_irq_lookup(const char *chipname, intc_enum enum_id)
+{
+	struct intc_map_entry *ptr;
+	struct intc_desc_int *d;
+	int irq = -1;
+
+	list_for_each_entry(d, &intc_list, list) {
+		int tagged;
+
+		if (strcmp(d->chip.name, chipname) != 0)
+			continue;
+
+		/*
+		 * Catch early lookups for subgroup VIRQs that have not
+		 * yet been allocated an IRQ. This already includes a
+		 * fast-path out if the tree is untagged, so there is no
+		 * need to explicitly test the root tree.
+		 */
+		tagged = radix_tree_tag_get(&d->tree, enum_id,
+					    INTC_TAG_VIRQ_NEEDS_ALLOC);
+		if (unlikely(tagged))
+			break;
+
+		ptr = radix_tree_lookup(&d->tree, enum_id);
+		if (ptr) {
+			irq = ptr - intc_irq_xlate;
+			break;
+		}
+	}
+
+	return irq;
+}
+EXPORT_SYMBOL_GPL(intc_irq_lookup);
+
+static int add_virq_to_pirq(unsigned int irq, unsigned int virq)
+{
+	struct intc_virq_list **last, *entry;
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	/* scan for duplicates */
+	last = (struct intc_virq_list **)&desc->handler_data;
+	for_each_virq(entry, desc->handler_data) {
+		if (entry->irq == virq)
+			return 0;
+		last = &entry->next;
+	}
+
+	entry = kzalloc(sizeof(struct intc_virq_list), GFP_ATOMIC);
+	if (!entry) {
+		pr_err("can't allocate VIRQ mapping for %d\n", virq);
+		return -ENOMEM;
+	}
+
+	entry->irq = virq;
+
+	*last = entry;
+
+	return 0;
+}
+
+static void intc_virq_handler(unsigned int irq, struct irq_desc *desc)
+{
+	struct intc_virq_list *entry, *vlist = get_irq_data(irq);
+	struct intc_desc_int *d = get_intc_desc(irq);
+
+	desc->chip->mask_ack(irq);
+
+	for_each_virq(entry, vlist) {
+		unsigned long addr, handle;
+
+		handle = (unsigned long)get_irq_data(entry->irq);
+		addr = INTC_REG(d, _INTC_ADDR_E(handle), 0);
+
+		if (intc_reg_fns[_INTC_FN(handle)](addr, handle, 0))
+			generic_handle_irq(entry->irq);
+	}
+
+	desc->chip->unmask(irq);
+}
+
+static unsigned long __init intc_subgroup_data(struct intc_subgroup *subgroup,
+					       struct intc_desc_int *d,
+					       unsigned int index)
+{
+	unsigned int fn = REG_FN_TEST_BASE + (subgroup->reg_width >> 3) - 1;
+
+	return _INTC_MK(fn, MODE_ENABLE_REG, intc_get_reg(d, subgroup->reg),
+			0, 1, (subgroup->reg_width - 1) - index);
+}
+
+static void __init intc_subgroup_init_one(struct intc_desc *desc,
+					  struct intc_desc_int *d,
+					  struct intc_subgroup *subgroup)
+{
+	struct intc_map_entry *mapped;
+	unsigned int pirq;
+	unsigned long flags;
+	int i;
+
+	mapped = radix_tree_lookup(&d->tree, subgroup->parent_id);
+	if (!mapped) {
+		WARN_ON(1);
+		return;
+	}
+
+	pirq = mapped - intc_irq_xlate;
+
+	raw_spin_lock_irqsave(&d->lock, flags);
+
+	for (i = 0; i < ARRAY_SIZE(subgroup->enum_ids); i++) {
+		struct intc_subgroup_entry *entry;
+		int err;
+
+		if (!subgroup->enum_ids[i])
+			continue;
+
+		entry = kmalloc(sizeof(*entry), GFP_NOWAIT);
+		if (!entry)
+			break;
+
+		entry->pirq = pirq;
+		entry->enum_id = subgroup->enum_ids[i];
+		entry->handle = intc_subgroup_data(subgroup, d, i);
+
+		err = radix_tree_insert(&d->tree, entry->enum_id, entry);
+		if (unlikely(err < 0))
+			break;
+
+		radix_tree_tag_set(&d->tree, entry->enum_id,
+				   INTC_TAG_VIRQ_NEEDS_ALLOC);
+	}
+
+	raw_spin_unlock_irqrestore(&d->lock, flags);
+}
+
+void __init intc_subgroup_init(struct intc_desc *desc, struct intc_desc_int *d)
+{
+	int i;
+
+	if (!desc->hw.subgroups)
+		return;
+
+	for (i = 0; i < desc->hw.nr_subgroups; i++)
+		intc_subgroup_init_one(desc, d, desc->hw.subgroups + i);
+}
+
+static void __init intc_subgroup_map(struct intc_desc_int *d)
+{
+	struct intc_subgroup_entry *entries[32];
+	unsigned long flags;
+	unsigned int nr_found;
+	int i;
+
+	raw_spin_lock_irqsave(&d->lock, flags);
+
+restart:
+	nr_found = radix_tree_gang_lookup_tag_slot(&d->tree,
+			(void ***)entries, 0, ARRAY_SIZE(entries),
+			INTC_TAG_VIRQ_NEEDS_ALLOC);
+
+	for (i = 0; i < nr_found; i++) {
+		struct intc_subgroup_entry *entry;
+		int irq;
+
+		entry = radix_tree_deref_slot((void **)entries[i]);
+		if (unlikely(!entry))
+			continue;
+		if (unlikely(entry == RADIX_TREE_RETRY))
+			goto restart;
+
+		irq = create_irq();
+		if (unlikely(irq < 0)) {
+			pr_err("no more free IRQs, bailing..\n");
+			break;
+		}
+
+		pr_info("Setting up a chained VIRQ from %d -> %d\n",
+			irq, entry->pirq);
+
+		intc_irq_xlate_set(irq, entry->enum_id, d);
+
+		set_irq_chip_and_handler_name(irq, get_irq_chip(entry->pirq),
+					      handle_simple_irq, "virq");
+		set_irq_chip_data(irq, get_irq_chip_data(entry->pirq));
+
+		set_irq_data(irq, (void *)entry->handle);
+
+		set_irq_chained_handler(entry->pirq, intc_virq_handler);
+		add_virq_to_pirq(entry->pirq, irq);
+
+		radix_tree_tag_clear(&d->tree, entry->enum_id,
+				     INTC_TAG_VIRQ_NEEDS_ALLOC);
+		radix_tree_replace_slot((void **)entries[i],
+					&intc_irq_xlate[irq]);
+	}
+
+	raw_spin_unlock_irqrestore(&d->lock, flags);
+}
+
+void __init intc_finalize(void)
+{
+	struct intc_desc_int *d;
+
+	list_for_each_entry(d, &intc_list, list)
+		if (radix_tree_tagged(&d->tree, INTC_TAG_VIRQ_NEEDS_ALLOC))
+			intc_subgroup_map(d);
+}