root/arch/x86/include/asm/i8259.h

DEFINITIONS

1. inb_pic
2. outb_pic
3. nr_legacy_irqs

#ifndef _ASM_X86_I8259_H
#define _ASM_X86_I8259_H

#include <linux/delay.h>

extern unsigned int cached_irq_mask;

#define __byte(x, y)            (((unsigned char *)&(y))[x])
#define cached_master_mask      (__byte(0, cached_irq_mask))
#define cached_slave_mask       (__byte(1, cached_irq_mask))

/* i8259A PIC registers */
#define PIC_MASTER_CMD          0x20
#define PIC_MASTER_IMR          0x21
#define PIC_MASTER_ISR          PIC_MASTER_CMD
#define PIC_MASTER_POLL         PIC_MASTER_ISR
#define PIC_MASTER_OCW3         PIC_MASTER_ISR
#define PIC_SLAVE_CMD           0xa0
#define PIC_SLAVE_IMR           0xa1

/* i8259A PIC related value */
#define PIC_CASCADE_IR          2
#define MASTER_ICW4_DEFAULT     0x01
#define SLAVE_ICW4_DEFAULT      0x01
#define PIC_ICW4_AEOI           2

extern raw_spinlock_t i8259A_lock;

/* the PIC may need a careful delay on some platforms, hence specific calls */
static inline unsigned char inb_pic(unsigned int port)
{
        unsigned char value = inb(port);

        /*
         * delay for some accesses to PIC on motherboard or in chipset
         * must be at least one microsecond, so be safe here:
         */
        udelay(2);

        return value;
}

static inline void outb_pic(unsigned char value, unsigned int port)
{
        outb(value, port);
        /*
         * delay for some accesses to PIC on motherboard or in chipset
         * must be at least one microsecond, so be safe here:
         */
        udelay(2);
}

extern struct irq_chip i8259A_chip;

struct legacy_pic {
        int nr_legacy_irqs;
        struct irq_chip *chip;
        void (*mask)(unsigned int irq);
        void (*unmask)(unsigned int irq);
        void (*mask_all)(void);
        void (*restore_mask)(void);
        void (*init)(int auto_eoi);
        int (*irq_pending)(unsigned int irq);
        void (*make_irq)(unsigned int irq);
};

extern struct legacy_pic *legacy_pic;
extern struct legacy_pic null_legacy_pic;

static inline int nr_legacy_irqs(void)
{
        return legacy_pic->nr_legacy_irqs;
}

#endif /* _ASM_X86_I8259_H */