Loading...
1/*
2 * i8259 interrupt controller driver.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 */
9#undef DEBUG
10
11#include <linux/ioport.h>
12#include <linux/interrupt.h>
13#include <linux/kernel.h>
14#include <linux/delay.h>
15#include <asm/io.h>
16#include <asm/i8259.h>
17#include <asm/prom.h>
18
19static volatile void __iomem *pci_intack; /* RO, gives us the irq vector */
20
21static unsigned char cached_8259[2] = { 0xff, 0xff };
22#define cached_A1 (cached_8259[0])
23#define cached_21 (cached_8259[1])
24
25static DEFINE_RAW_SPINLOCK(i8259_lock);
26
27static struct irq_domain *i8259_host;
28
29/*
30 * Acknowledge the IRQ using either the PCI host bridge's interrupt
31 * acknowledge feature or poll. How i8259_init() is called determines
32 * which is called. It should be noted that polling is broken on some
33 * IBM and Motorola PReP boxes so we must use the int-ack feature on them.
34 */
35unsigned int i8259_irq(void)
36{
37 int irq;
38 int lock = 0;
39
40 /* Either int-ack or poll for the IRQ */
41 if (pci_intack)
42 irq = readb(pci_intack);
43 else {
44 raw_spin_lock(&i8259_lock);
45 lock = 1;
46
47 /* Perform an interrupt acknowledge cycle on controller 1. */
48 outb(0x0C, 0x20); /* prepare for poll */
49 irq = inb(0x20) & 7;
50 if (irq == 2 ) {
51 /*
52 * Interrupt is cascaded so perform interrupt
53 * acknowledge on controller 2.
54 */
55 outb(0x0C, 0xA0); /* prepare for poll */
56 irq = (inb(0xA0) & 7) + 8;
57 }
58 }
59
60 if (irq == 7) {
61 /*
62 * This may be a spurious interrupt.
63 *
64 * Read the interrupt status register (ISR). If the most
65 * significant bit is not set then there is no valid
66 * interrupt.
67 */
68 if (!pci_intack)
69 outb(0x0B, 0x20); /* ISR register */
70 if(~inb(0x20) & 0x80)
71 irq = 0;
72 } else if (irq == 0xff)
73 irq = 0;
74
75 if (lock)
76 raw_spin_unlock(&i8259_lock);
77 return irq;
78}
79
80static void i8259_mask_and_ack_irq(struct irq_data *d)
81{
82 unsigned long flags;
83
84 raw_spin_lock_irqsave(&i8259_lock, flags);
85 if (d->irq > 7) {
86 cached_A1 |= 1 << (d->irq-8);
87 inb(0xA1); /* DUMMY */
88 outb(cached_A1, 0xA1);
89 outb(0x20, 0xA0); /* Non-specific EOI */
90 outb(0x20, 0x20); /* Non-specific EOI to cascade */
91 } else {
92 cached_21 |= 1 << d->irq;
93 inb(0x21); /* DUMMY */
94 outb(cached_21, 0x21);
95 outb(0x20, 0x20); /* Non-specific EOI */
96 }
97 raw_spin_unlock_irqrestore(&i8259_lock, flags);
98}
99
100static void i8259_set_irq_mask(int irq_nr)
101{
102 outb(cached_A1,0xA1);
103 outb(cached_21,0x21);
104}
105
106static void i8259_mask_irq(struct irq_data *d)
107{
108 unsigned long flags;
109
110 pr_debug("i8259_mask_irq(%d)\n", d->irq);
111
112 raw_spin_lock_irqsave(&i8259_lock, flags);
113 if (d->irq < 8)
114 cached_21 |= 1 << d->irq;
115 else
116 cached_A1 |= 1 << (d->irq-8);
117 i8259_set_irq_mask(d->irq);
118 raw_spin_unlock_irqrestore(&i8259_lock, flags);
119}
120
121static void i8259_unmask_irq(struct irq_data *d)
122{
123 unsigned long flags;
124
125 pr_debug("i8259_unmask_irq(%d)\n", d->irq);
126
127 raw_spin_lock_irqsave(&i8259_lock, flags);
128 if (d->irq < 8)
129 cached_21 &= ~(1 << d->irq);
130 else
131 cached_A1 &= ~(1 << (d->irq-8));
132 i8259_set_irq_mask(d->irq);
133 raw_spin_unlock_irqrestore(&i8259_lock, flags);
134}
135
136static struct irq_chip i8259_pic = {
137 .name = "i8259",
138 .irq_mask = i8259_mask_irq,
139 .irq_disable = i8259_mask_irq,
140 .irq_unmask = i8259_unmask_irq,
141 .irq_mask_ack = i8259_mask_and_ack_irq,
142};
143
144static struct resource pic1_iores = {
145 .name = "8259 (master)",
146 .start = 0x20,
147 .end = 0x21,
148 .flags = IORESOURCE_BUSY,
149};
150
151static struct resource pic2_iores = {
152 .name = "8259 (slave)",
153 .start = 0xa0,
154 .end = 0xa1,
155 .flags = IORESOURCE_BUSY,
156};
157
158static struct resource pic_edgectrl_iores = {
159 .name = "8259 edge control",
160 .start = 0x4d0,
161 .end = 0x4d1,
162 .flags = IORESOURCE_BUSY,
163};
164
165static int i8259_host_match(struct irq_domain *h, struct device_node *node,
166 enum irq_domain_bus_token bus_token)
167{
168 struct device_node *of_node = irq_domain_get_of_node(h);
169 return of_node == NULL || of_node == node;
170}
171
172static int i8259_host_map(struct irq_domain *h, unsigned int virq,
173 irq_hw_number_t hw)
174{
175 pr_debug("i8259_host_map(%d, 0x%lx)\n", virq, hw);
176
177 /* We block the internal cascade */
178 if (hw == 2)
179 irq_set_status_flags(virq, IRQ_NOREQUEST);
180
181 /* We use the level handler only for now, we might want to
182 * be more cautious here but that works for now
183 */
184 irq_set_status_flags(virq, IRQ_LEVEL);
185 irq_set_chip_and_handler(virq, &i8259_pic, handle_level_irq);
186 return 0;
187}
188
189static int i8259_host_xlate(struct irq_domain *h, struct device_node *ct,
190 const u32 *intspec, unsigned int intsize,
191 irq_hw_number_t *out_hwirq, unsigned int *out_flags)
192{
193 static unsigned char map_isa_senses[4] = {
194 IRQ_TYPE_LEVEL_LOW,
195 IRQ_TYPE_LEVEL_HIGH,
196 IRQ_TYPE_EDGE_FALLING,
197 IRQ_TYPE_EDGE_RISING,
198 };
199
200 *out_hwirq = intspec[0];
201 if (intsize > 1 && intspec[1] < 4)
202 *out_flags = map_isa_senses[intspec[1]];
203 else
204 *out_flags = IRQ_TYPE_NONE;
205
206 return 0;
207}
208
209static const struct irq_domain_ops i8259_host_ops = {
210 .match = i8259_host_match,
211 .map = i8259_host_map,
212 .xlate = i8259_host_xlate,
213};
214
215struct irq_domain *i8259_get_host(void)
216{
217 return i8259_host;
218}
219
220/**
221 * i8259_init - Initialize the legacy controller
222 * @node: device node of the legacy PIC (can be NULL, but then, it will match
223 * all interrupts, so beware)
224 * @intack_addr: PCI interrupt acknowledge (real) address which will return
225 * the active irq from the 8259
226 */
227void i8259_init(struct device_node *node, unsigned long intack_addr)
228{
229 unsigned long flags;
230
231 /* initialize the controller */
232 raw_spin_lock_irqsave(&i8259_lock, flags);
233
234 /* Mask all first */
235 outb(0xff, 0xA1);
236 outb(0xff, 0x21);
237
238 /* init master interrupt controller */
239 outb(0x11, 0x20); /* Start init sequence */
240 outb(0x00, 0x21); /* Vector base */
241 outb(0x04, 0x21); /* edge triggered, Cascade (slave) on IRQ2 */
242 outb(0x01, 0x21); /* Select 8086 mode */
243
244 /* init slave interrupt controller */
245 outb(0x11, 0xA0); /* Start init sequence */
246 outb(0x08, 0xA1); /* Vector base */
247 outb(0x02, 0xA1); /* edge triggered, Cascade (slave) on IRQ2 */
248 outb(0x01, 0xA1); /* Select 8086 mode */
249
250 /* That thing is slow */
251 udelay(100);
252
253 /* always read ISR */
254 outb(0x0B, 0x20);
255 outb(0x0B, 0xA0);
256
257 /* Unmask the internal cascade */
258 cached_21 &= ~(1 << 2);
259
260 /* Set interrupt masks */
261 outb(cached_A1, 0xA1);
262 outb(cached_21, 0x21);
263
264 raw_spin_unlock_irqrestore(&i8259_lock, flags);
265
266 /* create a legacy host */
267 i8259_host = irq_domain_add_legacy_isa(node, &i8259_host_ops, NULL);
268 if (i8259_host == NULL) {
269 printk(KERN_ERR "i8259: failed to allocate irq host !\n");
270 return;
271 }
272
273 /* reserve our resources */
274 /* XXX should we continue doing that ? it seems to cause problems
275 * with further requesting of PCI IO resources for that range...
276 * need to look into it.
277 */
278 request_resource(&ioport_resource, &pic1_iores);
279 request_resource(&ioport_resource, &pic2_iores);
280 request_resource(&ioport_resource, &pic_edgectrl_iores);
281
282 if (intack_addr != 0)
283 pci_intack = ioremap(intack_addr, 1);
284
285 printk(KERN_INFO "i8259 legacy interrupt controller initialized\n");
286}
1/*
2 * i8259 interrupt controller driver.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 */
9#undef DEBUG
10
11#include <linux/init.h>
12#include <linux/ioport.h>
13#include <linux/interrupt.h>
14#include <linux/kernel.h>
15#include <linux/delay.h>
16#include <asm/io.h>
17#include <asm/i8259.h>
18#include <asm/prom.h>
19
20static volatile void __iomem *pci_intack; /* RO, gives us the irq vector */
21
22static unsigned char cached_8259[2] = { 0xff, 0xff };
23#define cached_A1 (cached_8259[0])
24#define cached_21 (cached_8259[1])
25
26static DEFINE_RAW_SPINLOCK(i8259_lock);
27
28static struct irq_host *i8259_host;
29
30/*
31 * Acknowledge the IRQ using either the PCI host bridge's interrupt
32 * acknowledge feature or poll. How i8259_init() is called determines
33 * which is called. It should be noted that polling is broken on some
34 * IBM and Motorola PReP boxes so we must use the int-ack feature on them.
35 */
36unsigned int i8259_irq(void)
37{
38 int irq;
39 int lock = 0;
40
41 /* Either int-ack or poll for the IRQ */
42 if (pci_intack)
43 irq = readb(pci_intack);
44 else {
45 raw_spin_lock(&i8259_lock);
46 lock = 1;
47
48 /* Perform an interrupt acknowledge cycle on controller 1. */
49 outb(0x0C, 0x20); /* prepare for poll */
50 irq = inb(0x20) & 7;
51 if (irq == 2 ) {
52 /*
53 * Interrupt is cascaded so perform interrupt
54 * acknowledge on controller 2.
55 */
56 outb(0x0C, 0xA0); /* prepare for poll */
57 irq = (inb(0xA0) & 7) + 8;
58 }
59 }
60
61 if (irq == 7) {
62 /*
63 * This may be a spurious interrupt.
64 *
65 * Read the interrupt status register (ISR). If the most
66 * significant bit is not set then there is no valid
67 * interrupt.
68 */
69 if (!pci_intack)
70 outb(0x0B, 0x20); /* ISR register */
71 if(~inb(0x20) & 0x80)
72 irq = NO_IRQ;
73 } else if (irq == 0xff)
74 irq = NO_IRQ;
75
76 if (lock)
77 raw_spin_unlock(&i8259_lock);
78 return irq;
79}
80
81static void i8259_mask_and_ack_irq(struct irq_data *d)
82{
83 unsigned long flags;
84
85 raw_spin_lock_irqsave(&i8259_lock, flags);
86 if (d->irq > 7) {
87 cached_A1 |= 1 << (d->irq-8);
88 inb(0xA1); /* DUMMY */
89 outb(cached_A1, 0xA1);
90 outb(0x20, 0xA0); /* Non-specific EOI */
91 outb(0x20, 0x20); /* Non-specific EOI to cascade */
92 } else {
93 cached_21 |= 1 << d->irq;
94 inb(0x21); /* DUMMY */
95 outb(cached_21, 0x21);
96 outb(0x20, 0x20); /* Non-specific EOI */
97 }
98 raw_spin_unlock_irqrestore(&i8259_lock, flags);
99}
100
101static void i8259_set_irq_mask(int irq_nr)
102{
103 outb(cached_A1,0xA1);
104 outb(cached_21,0x21);
105}
106
107static void i8259_mask_irq(struct irq_data *d)
108{
109 unsigned long flags;
110
111 pr_debug("i8259_mask_irq(%d)\n", d->irq);
112
113 raw_spin_lock_irqsave(&i8259_lock, flags);
114 if (d->irq < 8)
115 cached_21 |= 1 << d->irq;
116 else
117 cached_A1 |= 1 << (d->irq-8);
118 i8259_set_irq_mask(d->irq);
119 raw_spin_unlock_irqrestore(&i8259_lock, flags);
120}
121
122static void i8259_unmask_irq(struct irq_data *d)
123{
124 unsigned long flags;
125
126 pr_debug("i8259_unmask_irq(%d)\n", d->irq);
127
128 raw_spin_lock_irqsave(&i8259_lock, flags);
129 if (d->irq < 8)
130 cached_21 &= ~(1 << d->irq);
131 else
132 cached_A1 &= ~(1 << (d->irq-8));
133 i8259_set_irq_mask(d->irq);
134 raw_spin_unlock_irqrestore(&i8259_lock, flags);
135}
136
137static struct irq_chip i8259_pic = {
138 .name = "i8259",
139 .irq_mask = i8259_mask_irq,
140 .irq_disable = i8259_mask_irq,
141 .irq_unmask = i8259_unmask_irq,
142 .irq_mask_ack = i8259_mask_and_ack_irq,
143};
144
145static struct resource pic1_iores = {
146 .name = "8259 (master)",
147 .start = 0x20,
148 .end = 0x21,
149 .flags = IORESOURCE_BUSY,
150};
151
152static struct resource pic2_iores = {
153 .name = "8259 (slave)",
154 .start = 0xa0,
155 .end = 0xa1,
156 .flags = IORESOURCE_BUSY,
157};
158
159static struct resource pic_edgectrl_iores = {
160 .name = "8259 edge control",
161 .start = 0x4d0,
162 .end = 0x4d1,
163 .flags = IORESOURCE_BUSY,
164};
165
166static int i8259_host_match(struct irq_host *h, struct device_node *node)
167{
168 return h->of_node == NULL || h->of_node == node;
169}
170
171static int i8259_host_map(struct irq_host *h, unsigned int virq,
172 irq_hw_number_t hw)
173{
174 pr_debug("i8259_host_map(%d, 0x%lx)\n", virq, hw);
175
176 /* We block the internal cascade */
177 if (hw == 2)
178 irq_set_status_flags(virq, IRQ_NOREQUEST);
179
180 /* We use the level handler only for now, we might want to
181 * be more cautious here but that works for now
182 */
183 irq_set_status_flags(virq, IRQ_LEVEL);
184 irq_set_chip_and_handler(virq, &i8259_pic, handle_level_irq);
185 return 0;
186}
187
188static int i8259_host_xlate(struct irq_host *h, struct device_node *ct,
189 const u32 *intspec, unsigned int intsize,
190 irq_hw_number_t *out_hwirq, unsigned int *out_flags)
191{
192 static unsigned char map_isa_senses[4] = {
193 IRQ_TYPE_LEVEL_LOW,
194 IRQ_TYPE_LEVEL_HIGH,
195 IRQ_TYPE_EDGE_FALLING,
196 IRQ_TYPE_EDGE_RISING,
197 };
198
199 *out_hwirq = intspec[0];
200 if (intsize > 1 && intspec[1] < 4)
201 *out_flags = map_isa_senses[intspec[1]];
202 else
203 *out_flags = IRQ_TYPE_NONE;
204
205 return 0;
206}
207
208static struct irq_host_ops i8259_host_ops = {
209 .match = i8259_host_match,
210 .map = i8259_host_map,
211 .xlate = i8259_host_xlate,
212};
213
214struct irq_host *i8259_get_host(void)
215{
216 return i8259_host;
217}
218
219/**
220 * i8259_init - Initialize the legacy controller
221 * @node: device node of the legacy PIC (can be NULL, but then, it will match
222 * all interrupts, so beware)
223 * @intack_addr: PCI interrupt acknowledge (real) address which will return
224 * the active irq from the 8259
225 */
226void i8259_init(struct device_node *node, unsigned long intack_addr)
227{
228 unsigned long flags;
229
230 /* initialize the controller */
231 raw_spin_lock_irqsave(&i8259_lock, flags);
232
233 /* Mask all first */
234 outb(0xff, 0xA1);
235 outb(0xff, 0x21);
236
237 /* init master interrupt controller */
238 outb(0x11, 0x20); /* Start init sequence */
239 outb(0x00, 0x21); /* Vector base */
240 outb(0x04, 0x21); /* edge tiggered, Cascade (slave) on IRQ2 */
241 outb(0x01, 0x21); /* Select 8086 mode */
242
243 /* init slave interrupt controller */
244 outb(0x11, 0xA0); /* Start init sequence */
245 outb(0x08, 0xA1); /* Vector base */
246 outb(0x02, 0xA1); /* edge triggered, Cascade (slave) on IRQ2 */
247 outb(0x01, 0xA1); /* Select 8086 mode */
248
249 /* That thing is slow */
250 udelay(100);
251
252 /* always read ISR */
253 outb(0x0B, 0x20);
254 outb(0x0B, 0xA0);
255
256 /* Unmask the internal cascade */
257 cached_21 &= ~(1 << 2);
258
259 /* Set interrupt masks */
260 outb(cached_A1, 0xA1);
261 outb(cached_21, 0x21);
262
263 raw_spin_unlock_irqrestore(&i8259_lock, flags);
264
265 /* create a legacy host */
266 i8259_host = irq_alloc_host(node, IRQ_HOST_MAP_LEGACY,
267 0, &i8259_host_ops, 0);
268 if (i8259_host == NULL) {
269 printk(KERN_ERR "i8259: failed to allocate irq host !\n");
270 return;
271 }
272
273 /* reserve our resources */
274 /* XXX should we continue doing that ? it seems to cause problems
275 * with further requesting of PCI IO resources for that range...
276 * need to look into it.
277 */
278 request_resource(&ioport_resource, &pic1_iores);
279 request_resource(&ioport_resource, &pic2_iores);
280 request_resource(&ioport_resource, &pic_edgectrl_iores);
281
282 if (intack_addr != 0)
283 pci_intack = ioremap(intack_addr, 1);
284
285 printk(KERN_INFO "i8259 legacy interrupt controller initialized\n");
286}