--- /dev/null
+/*
+ * 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 <linux/export.h>
+#include "internals.h"
+
+static struct intc_map_entry intc_irq_xlate[INTC_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_data *data = irq_get_irq_data(irq);
+
+ /* scan for duplicates */
+ last = (struct intc_virq_list **)&data->handler_data;
+ for_each_virq(entry, data->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 irq_data *data = irq_get_irq_data(irq);
+ struct irq_chip *chip = irq_data_get_irq_chip(data);
+ struct intc_virq_list *entry, *vlist = irq_data_get_irq_handler_data(data);
+ struct intc_desc_int *d = get_intc_desc(irq);
+
+ chip->irq_mask_ack(data);
+
+ for_each_virq(entry, vlist) {
+ unsigned long addr, handle;
+
+ handle = (unsigned long)irq_get_handler_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);
+ }
+
+ chip->irq_unmask(data);
+}
+
+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 (radix_tree_deref_retry(entry))
+ goto restart;
+
+ irq = irq_alloc_desc(numa_node_id());
+ if (unlikely(irq < 0)) {
+ pr_err("no more free IRQs, bailing..\n");
+ break;
+ }
+
+ activate_irq(irq);
+
+ pr_info("Setting up a chained VIRQ from %d -> %d\n",
+ irq, entry->pirq);
+
+ intc_irq_xlate_set(irq, entry->enum_id, d);
+
+ irq_set_chip_and_handler_name(irq, irq_get_chip(entry->pirq),
+ handle_simple_irq, "virq");
+ irq_set_chip_data(irq, irq_get_chip_data(entry->pirq));
+
+ irq_set_handler_data(irq, (void *)entry->handle);
+
+ /*
+ * Set the virtual IRQ as non-threadable.
+ */
+ irq_set_nothread(irq);
+
+ irq_set_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);
+}
Code Review / kvmfornfv.git / blobdiff