linux/arch/mips/include/asm/irq.h

/*
 * 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.
 *
 * Copyright (C) 1994 by Waldorf GMBH, written by Ralf Baechle
 * Copyright (C) 1995, 96, 97, 98, 99, 2000, 01, 02, 03 by Ralf Baechle
 */
#ifndef _ASM_IRQ_H
#define _ASM_IRQ_H

#include <linux/linkage.h>
#include <linux/smp.h>

#include <asm/mipsmtregs.h>

#include <irq.h>

static inline void irq_dispose_mapping(unsigned int virq)
{
	return;
}

#ifdef CONFIG_I8259
static inline int irq_canonicalize(int irq)
{
	return ((irq == I8259A_IRQ_BASE + 2) ? I8259A_IRQ_BASE + 9 : irq);
}
#else
#define irq_canonicalize(irq) (irq)	/* Sane hardware, sane code ... */
#endif

#ifdef CONFIG_MIPS_MT_SMTC

struct irqaction;

extern unsigned long irq_hwmask[];
extern int setup_irq_smtc(unsigned int irq, struct irqaction * new,
                          unsigned long hwmask);

static inline void smtc_im_ack_irq(unsigned int irq)
{
	if (irq_hwmask[irq] & ST0_IM)
		set_c0_status(irq_hwmask[irq] & ST0_IM);
}

#else

static inline void smtc_im_ack_irq(unsigned int irq)
{
}

#endif /* CONFIG_MIPS_MT_SMTC */

#ifdef CONFIG_MIPS_MT_SMTC_IRQAFF
#include <linux/cpumask.h>

extern int plat_set_irq_affinity(struct irq_data *d,
				 const struct cpumask *affinity, bool force);
extern void smtc_forward_irq(struct irq_data *d);

/*
 * IRQ affinity hook invoked at the beginning of interrupt dispatch
 * if option is enabled.
 *
 * Up through Linux 2.6.22 (at least) cpumask operations are very
 * inefficient on MIPS.  Initial prototypes of SMTC IRQ affinity
 * used a "fast path" per-IRQ-descriptor cache of affinity information
 * to reduce latency.  As there is a project afoot to optimize the
 * cpumask implementations, this version is optimistically assuming
 * that cpumask.h macro overhead is reasonable during interrupt dispatch.
 */
static inline int handle_on_other_cpu(unsigned int irq)
{
	struct irq_data *d = irq_get_irq_data(irq);

	if (cpumask_test_cpu(smp_processor_id(), d->affinity))
		return 0;
	smtc_forward_irq(d);
	return 1;
}

#else /* Not doing SMTC affinity */

static inline int handle_on_other_cpu(unsigned int irq) { return 0; }

#endif /* CONFIG_MIPS_MT_SMTC_IRQAFF */

#ifdef CONFIG_MIPS_MT_SMTC_IM_BACKSTOP

static inline void smtc_im_backstop(unsigned int irq)
{
	if (irq_hwmask[irq] & 0x0000ff00)
		write_c0_tccontext(read_c0_tccontext() &
				   ~(irq_hwmask[irq] & 0x0000ff00));
}

/*
 * Clear interrupt mask handling "backstop" if irq_hwmask
 * entry so indicates. This implies that the ack() or end()
 * functions will take over re-enabling the low-level mask.
 * Otherwise it will be done on return from exception.
 */
static inline int smtc_handle_on_other_cpu(unsigned int irq)
{
	int ret = handle_on_other_cpu(irq);

	if (!ret)
		smtc_im_backstop(irq);
	return ret;
}

#else

static inline void smtc_im_backstop(unsigned int irq) { }
static inline int smtc_handle_on_other_cpu(unsigned int irq)
{
	return handle_on_other_cpu(irq);
}

#endif

extern void do_IRQ(unsigned int irq);

#ifdef CONFIG_MIPS_MT_SMTC_IRQAFF

extern void do_IRQ_no_affinity(unsigned int irq);

#endif /* CONFIG_MIPS_MT_SMTC_IRQAFF */

extern void arch_init_irq(void);
extern void spurious_interrupt(void);

extern int allocate_irqno(void);
extern void alloc_legacy_irqno(void);
extern void free_irqno(unsigned int irq);

/*
 * Before R2 the timer and performance counter interrupts were both fixed to
 * IE7.  Since R2 their number has to be read from the c0_intctl register.
 */
#define CP0_LEGACY_COMPARE_IRQ 7

extern int cp0_compare_irq;
extern int cp0_compare_irq_shift;
extern int cp0_perfcount_irq;

#endif /* _ASM_IRQ_H */