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/*
* Dynamic IRQ management
*
* Copyright (C) 2010 Paul Mundt
*
* Modelled after arch/x86/kernel/apic/io_apic.c
*
* 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/irq.h>
#include <linux/bitmap.h>
#include <linux/spinlock.h>
#include "internals.h" /* only for activate_irq() damage.. */
/*
* The intc_irq_map provides a global map of bound IRQ vectors for a
* given platform. Allocation of IRQs are either static through the CPU
* vector map, or dynamic in the case of board mux vectors or MSI.
*
* As this is a central point for all IRQ controllers on the system,
* each of the available sources are mapped out here. This combined with
* sparseirq makes it quite trivial to keep the vector map tightly packed
* when dynamically creating IRQs, as well as tying in to otherwise
* unused irq_desc positions in the sparse array.
*/
static DECLARE_BITMAP(intc_irq_map, NR_IRQS);
static DEFINE_RAW_SPINLOCK(vector_lock);
/*
* Dynamic IRQ allocation and deallocation
*/
unsigned int create_irq_nr(unsigned int irq_want, int node)
{
unsigned int irq = 0, new;
unsigned long flags;
raw_spin_lock_irqsave(&vector_lock, flags);
/*
* First try the wanted IRQ
*/
if (test_and_set_bit(irq_want, intc_irq_map) == 0) {
new = irq_want;
} else {
/* .. then fall back to scanning. */
new = find_first_zero_bit(intc_irq_map, nr_irqs);
if (unlikely(new == nr_irqs))
goto out_unlock;
__set_bit(new, intc_irq_map);
}
raw_spin_unlock_irqrestore(&vector_lock, flags);
irq = irq_alloc_desc_at(new, node);
if (unlikely(irq != new)) {
pr_err("can't get irq_desc for %d\n", new);
return 0;
}
activate_irq(irq);
return 0;
out_unlock:
raw_spin_unlock_irqrestore(&vector_lock, flags);
return 0;
}
int create_irq(void)
{
int nid = cpu_to_node(smp_processor_id());
int irq;
irq = create_irq_nr(NR_IRQS_LEGACY, nid);
if (irq == 0)
irq = -1;
return irq;
}
void destroy_irq(unsigned int irq)
{
unsigned long flags;
irq_free_desc(irq);
raw_spin_lock_irqsave(&vector_lock, flags);
__clear_bit(irq, intc_irq_map);
raw_spin_unlock_irqrestore(&vector_lock, flags);
}
int reserve_irq_vector(unsigned int irq)
{
unsigned long flags;
int ret = 0;
raw_spin_lock_irqsave(&vector_lock, flags);
if (test_and_set_bit(irq, intc_irq_map))
ret = -EBUSY;
raw_spin_unlock_irqrestore(&vector_lock, flags);
return ret;
}
void reserve_intc_vectors(struct intc_vect *vectors, unsigned int nr_vecs)
{
unsigned long flags;
int i;
raw_spin_lock_irqsave(&vector_lock, flags);
for (i = 0; i < nr_vecs; i++)
__set_bit(evt2irq(vectors[i].vect), intc_irq_map);
raw_spin_unlock_irqrestore(&vector_lock, flags);
}
void reserve_irq_legacy(void)
{
unsigned long flags;
int i, j;
raw_spin_lock_irqsave(&vector_lock, flags);
j = find_first_bit(intc_irq_map, nr_irqs);
for (i = 0; i < j; i++)
__set_bit(i, intc_irq_map);
raw_spin_unlock_irqrestore(&vector_lock, flags);
}
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