sh: intc: Split up the INTC code.

This splits up the sh intc core in to something more vaguely resembling
a subsystem. Most of the functionality was alread fairly well
compartmentalized, and there were only a handful of interdependencies
that needed to be resolved in the process.

This also serves as future-proofing for the genirq and sparseirq rework,
which will make some of the split out functionality wholly generic,
allowing things to be killed off in place with minimal migration pain.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

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 00000000000..643dfd4d205
--- /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);
+}