/*
* 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_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 = 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);
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);
}
