1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/arch/arm/mach-footbridge/irq.c
4  *
5  *  Copyright (C) 1996-2000 Russell King
6  *
7  *  Changelog:
8  *   22-Aug-1998 RMK	Restructured IRQ routines
9  *   03-Sep-1998 PJB	Merged CATS support
10  *   20-Jan-1998 RMK	Started merge of EBSA286, CATS and NetWinder
11  *   26-Jan-1999 PJB	Don't use IACK on CATS
12  *   16-Mar-1999 RMK	Added autodetect of ISA PICs
13  */
14 #include <linux/ioport.h>
15 #include <linux/interrupt.h>
16 #include <linux/list.h>
17 #include <linux/init.h>
18 #include <linux/io.h>
19 #include <linux/spinlock.h>
20 
21 #include <asm/mach/irq.h>
22 
23 #include <mach/hardware.h>
24 #include <asm/hardware/dec21285.h>
25 #include <asm/irq.h>
26 #include <asm/mach-types.h>
27 
28 #include "common.h"
29 
30 static void isa_mask_pic_lo_irq(struct irq_data *d)
31 {
32 	unsigned int mask = 1 << (d->irq & 7);
33 
34 	outb(inb(PIC_MASK_LO) | mask, PIC_MASK_LO);
35 }
36 
37 static void isa_ack_pic_lo_irq(struct irq_data *d)
38 {
39 	unsigned int mask = 1 << (d->irq & 7);
40 
41 	outb(inb(PIC_MASK_LO) | mask, PIC_MASK_LO);
42 	outb(0x20, PIC_LO);
43 }
44 
45 static void isa_unmask_pic_lo_irq(struct irq_data *d)
46 {
47 	unsigned int mask = 1 << (d->irq & 7);
48 
49 	outb(inb(PIC_MASK_LO) & ~mask, PIC_MASK_LO);
50 }
51 
52 static struct irq_chip isa_lo_chip = {
53 	.irq_ack	= isa_ack_pic_lo_irq,
54 	.irq_mask	= isa_mask_pic_lo_irq,
55 	.irq_unmask	= isa_unmask_pic_lo_irq,
56 };
57 
58 static void isa_mask_pic_hi_irq(struct irq_data *d)
59 {
60 	unsigned int mask = 1 << (d->irq & 7);
61 
62 	outb(inb(PIC_MASK_HI) | mask, PIC_MASK_HI);
63 }
64 
65 static void isa_ack_pic_hi_irq(struct irq_data *d)
66 {
67 	unsigned int mask = 1 << (d->irq & 7);
68 
69 	outb(inb(PIC_MASK_HI) | mask, PIC_MASK_HI);
70 	outb(0x62, PIC_LO);
71 	outb(0x20, PIC_HI);
72 }
73 
74 static void isa_unmask_pic_hi_irq(struct irq_data *d)
75 {
76 	unsigned int mask = 1 << (d->irq & 7);
77 
78 	outb(inb(PIC_MASK_HI) & ~mask, PIC_MASK_HI);
79 }
80 
81 static struct irq_chip isa_hi_chip = {
82 	.irq_ack	= isa_ack_pic_hi_irq,
83 	.irq_mask	= isa_mask_pic_hi_irq,
84 	.irq_unmask	= isa_unmask_pic_hi_irq,
85 };
86 
87 static void isa_irq_handler(struct irq_desc *desc)
88 {
89 	unsigned int isa_irq = *(unsigned char *)PCIIACK_BASE;
90 
91 	if (isa_irq < _ISA_IRQ(0) || isa_irq >= _ISA_IRQ(16)) {
92 		do_bad_IRQ(desc);
93 		return;
94 	}
95 
96 	generic_handle_irq(isa_irq);
97 }
98 
99 static struct irqaction irq_cascade = {
100 	.handler = no_action,
101 	.name = "cascade",
102 };
103 
104 static struct resource pic1_resource = {
105 	.name	= "pic1",
106 	.start	= 0x20,
107 	.end	= 0x3f,
108 };
109 
110 static struct resource pic2_resource = {
111 	.name	= "pic2",
112 	.start	= 0xa0,
113 	.end	= 0xbf,
114 };
115 
116 void __init isa_init_irq(unsigned int host_irq)
117 {
118 	unsigned int irq;
119 
120 	/*
121 	 * Setup, and then probe for an ISA PIC
122 	 * If the PIC is not there, then we
123 	 * ignore the PIC.
124 	 */
125 	outb(0x11, PIC_LO);
126 	outb(_ISA_IRQ(0), PIC_MASK_LO);	/* IRQ number		*/
127 	outb(0x04, PIC_MASK_LO);	/* Slave on Ch2		*/
128 	outb(0x01, PIC_MASK_LO);	/* x86			*/
129 	outb(0xf5, PIC_MASK_LO);	/* pattern: 11110101	*/
130 
131 	outb(0x11, PIC_HI);
132 	outb(_ISA_IRQ(8), PIC_MASK_HI);	/* IRQ number		*/
133 	outb(0x02, PIC_MASK_HI);	/* Slave on Ch1		*/
134 	outb(0x01, PIC_MASK_HI);	/* x86			*/
135 	outb(0xfa, PIC_MASK_HI);	/* pattern: 11111010	*/
136 
137 	outb(0x0b, PIC_LO);
138 	outb(0x0b, PIC_HI);
139 
140 	if (inb(PIC_MASK_LO) == 0xf5 && inb(PIC_MASK_HI) == 0xfa) {
141 		outb(0xff, PIC_MASK_LO);/* mask all IRQs	*/
142 		outb(0xff, PIC_MASK_HI);/* mask all IRQs	*/
143 	} else {
144 		printk(KERN_INFO "IRQ: ISA PIC not found\n");
145 		host_irq = (unsigned int)-1;
146 	}
147 
148 	if (host_irq != (unsigned int)-1) {
149 		for (irq = _ISA_IRQ(0); irq < _ISA_IRQ(8); irq++) {
150 			irq_set_chip_and_handler(irq, &isa_lo_chip,
151 						 handle_level_irq);
152 			irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
153 		}
154 
155 		for (irq = _ISA_IRQ(8); irq < _ISA_IRQ(16); irq++) {
156 			irq_set_chip_and_handler(irq, &isa_hi_chip,
157 						 handle_level_irq);
158 			irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
159 		}
160 
161 		request_resource(&ioport_resource, &pic1_resource);
162 		request_resource(&ioport_resource, &pic2_resource);
163 		setup_irq(IRQ_ISA_CASCADE, &irq_cascade);
164 
165 		irq_set_chained_handler(host_irq, isa_irq_handler);
166 
167 		/*
168 		 * On the NetWinder, don't automatically
169 		 * enable ISA IRQ11 when it is requested.
170 		 * There appears to be a missing pull-up
171 		 * resistor on this line.
172 		 */
173 		if (machine_is_netwinder())
174 			irq_modify_status(_ISA_IRQ(11),
175 				IRQ_NOREQUEST | IRQ_NOPROBE, IRQ_NOAUTOEN);
176 	}
177 }
178 
179 
180