1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_X86_I8259_H
3#define _ASM_X86_I8259_H
4
5#include <linux/delay.h>
6#include <asm/io.h>
7
8extern unsigned int cached_irq_mask;
9
10#define __byte(x, y) (((unsigned char *)&(y))[x])
11#define cached_master_mask (__byte(0, cached_irq_mask))
12#define cached_slave_mask (__byte(1, cached_irq_mask))
13
14/* i8259A PIC registers */
15#define PIC_MASTER_CMD 0x20
16#define PIC_MASTER_IMR 0x21
17#define PIC_MASTER_ISR PIC_MASTER_CMD
18#define PIC_MASTER_POLL PIC_MASTER_ISR
19#define PIC_MASTER_OCW3 PIC_MASTER_ISR
20#define PIC_SLAVE_CMD 0xa0
21#define PIC_SLAVE_IMR 0xa1
22#define PIC_ELCR1 0x4d0
23#define PIC_ELCR2 0x4d1
24
25/* i8259A PIC related value */
26#define PIC_CASCADE_IR 2
27#define MASTER_ICW4_DEFAULT 0x01
28#define SLAVE_ICW4_DEFAULT 0x01
29#define PIC_ICW4_AEOI 2
30
31extern raw_spinlock_t i8259A_lock;
32
33/* the PIC may need a careful delay on some platforms, hence specific calls */
34static inline unsigned char inb_pic(unsigned int port)
35{
36 unsigned char value = inb(port);
37
38 /*
39 * delay for some accesses to PIC on motherboard or in chipset
40 * must be at least one microsecond, so be safe here:
41 */
42 udelay(usec: 2);
43
44 return value;
45}
46
47static inline void outb_pic(unsigned char value, unsigned int port)
48{
49 outb(value, port);
50 /*
51 * delay for some accesses to PIC on motherboard or in chipset
52 * must be at least one microsecond, so be safe here:
53 */
54 udelay(usec: 2);
55}
56
57extern struct irq_chip i8259A_chip;
58
59struct legacy_pic {
60 int nr_legacy_irqs;
61 struct irq_chip *chip;
62 void (*mask)(unsigned int irq);
63 void (*unmask)(unsigned int irq);
64 void (*mask_all)(void);
65 void (*restore_mask)(void);
66 void (*init)(int auto_eoi);
67 int (*probe)(void);
68 int (*irq_pending)(unsigned int irq);
69 void (*make_irq)(unsigned int irq);
70};
71
72void legacy_pic_pcat_compat(void);
73
74extern struct legacy_pic *legacy_pic;
75extern struct legacy_pic null_legacy_pic;
76
77static inline bool has_legacy_pic(void)
78{
79 return legacy_pic != &null_legacy_pic;
80}
81
82static inline int nr_legacy_irqs(void)
83{
84 return legacy_pic->nr_legacy_irqs;
85}
86
87#endif /* _ASM_X86_I8259_H */
88

source code of linux/arch/x86/include/asm/i8259.h