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1#include <linux/linkage.h>
2#include <linux/errno.h>
3#include <linux/signal.h>
4#include <linux/sched.h>
5#include <linux/ioport.h>
6#include <linux/interrupt.h>
7#include <linux/timex.h>
8#include <linux/random.h>
9#include <linux/init.h>
10#include <linux/kernel_stat.h>
11#include <linux/syscore_ops.h>
12#include <linux/bitops.h>
13#include <linux/acpi.h>
14#include <linux/io.h>
15#include <linux/delay.h>
16
17#include <linux/atomic.h>
18#include <asm/timer.h>
19#include <asm/hw_irq.h>
20#include <asm/pgtable.h>
21#include <asm/desc.h>
22#include <asm/apic.h>
23#include <asm/i8259.h>
24
25/*
26 * This is the 'legacy' 8259A Programmable Interrupt Controller,
27 * present in the majority of PC/AT boxes.
28 * plus some generic x86 specific things if generic specifics makes
29 * any sense at all.
30 */
31static void init_8259A(int auto_eoi);
32
33static int i8259A_auto_eoi;
34DEFINE_RAW_SPINLOCK(i8259A_lock);
35
36/*
37 * 8259A PIC functions to handle ISA devices:
38 */
39
40/*
41 * This contains the irq mask for both 8259A irq controllers,
42 */
43unsigned int cached_irq_mask = 0xffff;
44
45/*
46 * Not all IRQs can be routed through the IO-APIC, eg. on certain (older)
47 * boards the timer interrupt is not really connected to any IO-APIC pin,
48 * it's fed to the master 8259A's IR0 line only.
49 *
50 * Any '1' bit in this mask means the IRQ is routed through the IO-APIC.
51 * this 'mixed mode' IRQ handling costs nothing because it's only used
52 * at IRQ setup time.
53 */
54unsigned long io_apic_irqs;
55
56static void mask_8259A_irq(unsigned int irq)
57{
58 unsigned int mask = 1 << irq;
59 unsigned long flags;
60
61 raw_spin_lock_irqsave(&i8259A_lock, flags);
62 cached_irq_mask |= mask;
63 if (irq & 8)
64 outb(cached_slave_mask, PIC_SLAVE_IMR);
65 else
66 outb(cached_master_mask, PIC_MASTER_IMR);
67 raw_spin_unlock_irqrestore(&i8259A_lock, flags);
68}
69
70static void disable_8259A_irq(struct irq_data *data)
71{
72 mask_8259A_irq(data->irq);
73}
74
75static void unmask_8259A_irq(unsigned int irq)
76{
77 unsigned int mask = ~(1 << irq);
78 unsigned long flags;
79
80 raw_spin_lock_irqsave(&i8259A_lock, flags);
81 cached_irq_mask &= mask;
82 if (irq & 8)
83 outb(cached_slave_mask, PIC_SLAVE_IMR);
84 else
85 outb(cached_master_mask, PIC_MASTER_IMR);
86 raw_spin_unlock_irqrestore(&i8259A_lock, flags);
87}
88
89static void enable_8259A_irq(struct irq_data *data)
90{
91 unmask_8259A_irq(data->irq);
92}
93
94static int i8259A_irq_pending(unsigned int irq)
95{
96 unsigned int mask = 1<<irq;
97 unsigned long flags;
98 int ret;
99
100 raw_spin_lock_irqsave(&i8259A_lock, flags);
101 if (irq < 8)
102 ret = inb(PIC_MASTER_CMD) & mask;
103 else
104 ret = inb(PIC_SLAVE_CMD) & (mask >> 8);
105 raw_spin_unlock_irqrestore(&i8259A_lock, flags);
106
107 return ret;
108}
109
110static void make_8259A_irq(unsigned int irq)
111{
112 disable_irq_nosync(irq);
113 io_apic_irqs &= ~(1<<irq);
114 irq_set_chip_and_handler_name(irq, &i8259A_chip, handle_level_irq,
115 i8259A_chip.name);
116 enable_irq(irq);
117}
118
119/*
120 * This function assumes to be called rarely. Switching between
121 * 8259A registers is slow.
122 * This has to be protected by the irq controller spinlock
123 * before being called.
124 */
125static inline int i8259A_irq_real(unsigned int irq)
126{
127 int value;
128 int irqmask = 1<<irq;
129
130 if (irq < 8) {
131 outb(0x0B, PIC_MASTER_CMD); /* ISR register */
132 value = inb(PIC_MASTER_CMD) & irqmask;
133 outb(0x0A, PIC_MASTER_CMD); /* back to the IRR register */
134 return value;
135 }
136 outb(0x0B, PIC_SLAVE_CMD); /* ISR register */
137 value = inb(PIC_SLAVE_CMD) & (irqmask >> 8);
138 outb(0x0A, PIC_SLAVE_CMD); /* back to the IRR register */
139 return value;
140}
141
142/*
143 * Careful! The 8259A is a fragile beast, it pretty
144 * much _has_ to be done exactly like this (mask it
145 * first, _then_ send the EOI, and the order of EOI
146 * to the two 8259s is important!
147 */
148static void mask_and_ack_8259A(struct irq_data *data)
149{
150 unsigned int irq = data->irq;
151 unsigned int irqmask = 1 << irq;
152 unsigned long flags;
153
154 raw_spin_lock_irqsave(&i8259A_lock, flags);
155 /*
156 * Lightweight spurious IRQ detection. We do not want
157 * to overdo spurious IRQ handling - it's usually a sign
158 * of hardware problems, so we only do the checks we can
159 * do without slowing down good hardware unnecessarily.
160 *
161 * Note that IRQ7 and IRQ15 (the two spurious IRQs
162 * usually resulting from the 8259A-1|2 PICs) occur
163 * even if the IRQ is masked in the 8259A. Thus we
164 * can check spurious 8259A IRQs without doing the
165 * quite slow i8259A_irq_real() call for every IRQ.
166 * This does not cover 100% of spurious interrupts,
167 * but should be enough to warn the user that there
168 * is something bad going on ...
169 */
170 if (cached_irq_mask & irqmask)
171 goto spurious_8259A_irq;
172 cached_irq_mask |= irqmask;
173
174handle_real_irq:
175 if (irq & 8) {
176 inb(PIC_SLAVE_IMR); /* DUMMY - (do we need this?) */
177 outb(cached_slave_mask, PIC_SLAVE_IMR);
178 /* 'Specific EOI' to slave */
179 outb(0x60+(irq&7), PIC_SLAVE_CMD);
180 /* 'Specific EOI' to master-IRQ2 */
181 outb(0x60+PIC_CASCADE_IR, PIC_MASTER_CMD);
182 } else {
183 inb(PIC_MASTER_IMR); /* DUMMY - (do we need this?) */
184 outb(cached_master_mask, PIC_MASTER_IMR);
185 outb(0x60+irq, PIC_MASTER_CMD); /* 'Specific EOI to master */
186 }
187 raw_spin_unlock_irqrestore(&i8259A_lock, flags);
188 return;
189
190spurious_8259A_irq:
191 /*
192 * this is the slow path - should happen rarely.
193 */
194 if (i8259A_irq_real(irq))
195 /*
196 * oops, the IRQ _is_ in service according to the
197 * 8259A - not spurious, go handle it.
198 */
199 goto handle_real_irq;
200
201 {
202 static int spurious_irq_mask;
203 /*
204 * At this point we can be sure the IRQ is spurious,
205 * lets ACK and report it. [once per IRQ]
206 */
207 if (!(spurious_irq_mask & irqmask)) {
208 printk(KERN_DEBUG
209 "spurious 8259A interrupt: IRQ%d.\n", irq);
210 spurious_irq_mask |= irqmask;
211 }
212 atomic_inc(&irq_err_count);
213 /*
214 * Theoretically we do not have to handle this IRQ,
215 * but in Linux this does not cause problems and is
216 * simpler for us.
217 */
218 goto handle_real_irq;
219 }
220}
221
222struct irq_chip i8259A_chip = {
223 .name = "XT-PIC",
224 .irq_mask = disable_8259A_irq,
225 .irq_disable = disable_8259A_irq,
226 .irq_unmask = enable_8259A_irq,
227 .irq_mask_ack = mask_and_ack_8259A,
228};
229
230static char irq_trigger[2];
231/**
232 * ELCR registers (0x4d0, 0x4d1) control edge/level of IRQ
233 */
234static void restore_ELCR(char *trigger)
235{
236 outb(trigger[0], 0x4d0);
237 outb(trigger[1], 0x4d1);
238}
239
240static void save_ELCR(char *trigger)
241{
242 /* IRQ 0,1,2,8,13 are marked as reserved */
243 trigger[0] = inb(0x4d0) & 0xF8;
244 trigger[1] = inb(0x4d1) & 0xDE;
245}
246
247static void i8259A_resume(void)
248{
249 init_8259A(i8259A_auto_eoi);
250 restore_ELCR(irq_trigger);
251}
252
253static int i8259A_suspend(void)
254{
255 save_ELCR(irq_trigger);
256 return 0;
257}
258
259static void i8259A_shutdown(void)
260{
261 /* Put the i8259A into a quiescent state that
262 * the kernel initialization code can get it
263 * out of.
264 */
265 outb(0xff, PIC_MASTER_IMR); /* mask all of 8259A-1 */
266 outb(0xff, PIC_SLAVE_IMR); /* mask all of 8259A-1 */
267}
268
269static struct syscore_ops i8259_syscore_ops = {
270 .suspend = i8259A_suspend,
271 .resume = i8259A_resume,
272 .shutdown = i8259A_shutdown,
273};
274
275static void mask_8259A(void)
276{
277 unsigned long flags;
278
279 raw_spin_lock_irqsave(&i8259A_lock, flags);
280
281 outb(0xff, PIC_MASTER_IMR); /* mask all of 8259A-1 */
282 outb(0xff, PIC_SLAVE_IMR); /* mask all of 8259A-2 */
283
284 raw_spin_unlock_irqrestore(&i8259A_lock, flags);
285}
286
287static void unmask_8259A(void)
288{
289 unsigned long flags;
290
291 raw_spin_lock_irqsave(&i8259A_lock, flags);
292
293 outb(cached_master_mask, PIC_MASTER_IMR); /* restore master IRQ mask */
294 outb(cached_slave_mask, PIC_SLAVE_IMR); /* restore slave IRQ mask */
295
296 raw_spin_unlock_irqrestore(&i8259A_lock, flags);
297}
298
299static void init_8259A(int auto_eoi)
300{
301 unsigned long flags;
302
303 i8259A_auto_eoi = auto_eoi;
304
305 raw_spin_lock_irqsave(&i8259A_lock, flags);
306
307 outb(0xff, PIC_MASTER_IMR); /* mask all of 8259A-1 */
308 outb(0xff, PIC_SLAVE_IMR); /* mask all of 8259A-2 */
309
310 /*
311 * outb_pic - this has to work on a wide range of PC hardware.
312 */
313 outb_pic(0x11, PIC_MASTER_CMD); /* ICW1: select 8259A-1 init */
314
315 /* ICW2: 8259A-1 IR0-7 mapped to 0x30-0x37 on x86-64,
316 to 0x20-0x27 on i386 */
317 outb_pic(IRQ0_VECTOR, PIC_MASTER_IMR);
318
319 /* 8259A-1 (the master) has a slave on IR2 */
320 outb_pic(1U << PIC_CASCADE_IR, PIC_MASTER_IMR);
321
322 if (auto_eoi) /* master does Auto EOI */
323 outb_pic(MASTER_ICW4_DEFAULT | PIC_ICW4_AEOI, PIC_MASTER_IMR);
324 else /* master expects normal EOI */
325 outb_pic(MASTER_ICW4_DEFAULT, PIC_MASTER_IMR);
326
327 outb_pic(0x11, PIC_SLAVE_CMD); /* ICW1: select 8259A-2 init */
328
329 /* ICW2: 8259A-2 IR0-7 mapped to IRQ8_VECTOR */
330 outb_pic(IRQ8_VECTOR, PIC_SLAVE_IMR);
331 /* 8259A-2 is a slave on master's IR2 */
332 outb_pic(PIC_CASCADE_IR, PIC_SLAVE_IMR);
333 /* (slave's support for AEOI in flat mode is to be investigated) */
334 outb_pic(SLAVE_ICW4_DEFAULT, PIC_SLAVE_IMR);
335
336 if (auto_eoi)
337 /*
338 * In AEOI mode we just have to mask the interrupt
339 * when acking.
340 */
341 i8259A_chip.irq_mask_ack = disable_8259A_irq;
342 else
343 i8259A_chip.irq_mask_ack = mask_and_ack_8259A;
344
345 udelay(100); /* wait for 8259A to initialize */
346
347 outb(cached_master_mask, PIC_MASTER_IMR); /* restore master IRQ mask */
348 outb(cached_slave_mask, PIC_SLAVE_IMR); /* restore slave IRQ mask */
349
350 raw_spin_unlock_irqrestore(&i8259A_lock, flags);
351}
352
353/*
354 * make i8259 a driver so that we can select pic functions at run time. the goal
355 * is to make x86 binary compatible among pc compatible and non-pc compatible
356 * platforms, such as x86 MID.
357 */
358
359static void legacy_pic_noop(void) { };
360static void legacy_pic_uint_noop(unsigned int unused) { };
361static void legacy_pic_int_noop(int unused) { };
362static int legacy_pic_irq_pending_noop(unsigned int irq)
363{
364 return 0;
365}
366
367struct legacy_pic null_legacy_pic = {
368 .nr_legacy_irqs = 0,
369 .chip = &dummy_irq_chip,
370 .mask = legacy_pic_uint_noop,
371 .unmask = legacy_pic_uint_noop,
372 .mask_all = legacy_pic_noop,
373 .restore_mask = legacy_pic_noop,
374 .init = legacy_pic_int_noop,
375 .irq_pending = legacy_pic_irq_pending_noop,
376 .make_irq = legacy_pic_uint_noop,
377};
378
379struct legacy_pic default_legacy_pic = {
380 .nr_legacy_irqs = NR_IRQS_LEGACY,
381 .chip = &i8259A_chip,
382 .mask = mask_8259A_irq,
383 .unmask = unmask_8259A_irq,
384 .mask_all = mask_8259A,
385 .restore_mask = unmask_8259A,
386 .init = init_8259A,
387 .irq_pending = i8259A_irq_pending,
388 .make_irq = make_8259A_irq,
389};
390
391struct legacy_pic *legacy_pic = &default_legacy_pic;
392
393static int __init i8259A_init_ops(void)
394{
395 if (legacy_pic == &default_legacy_pic)
396 register_syscore_ops(&i8259_syscore_ops);
397
398 return 0;
399}
400
401device_initcall(i8259A_init_ops);
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/linkage.h>
3#include <linux/errno.h>
4#include <linux/signal.h>
5#include <linux/sched.h>
6#include <linux/ioport.h>
7#include <linux/interrupt.h>
8#include <linux/irq.h>
9#include <linux/timex.h>
10#include <linux/random.h>
11#include <linux/init.h>
12#include <linux/kernel_stat.h>
13#include <linux/syscore_ops.h>
14#include <linux/bitops.h>
15#include <linux/acpi.h>
16#include <linux/io.h>
17#include <linux/delay.h>
18#include <linux/pgtable.h>
19
20#include <linux/atomic.h>
21#include <asm/timer.h>
22#include <asm/hw_irq.h>
23#include <asm/desc.h>
24#include <asm/apic.h>
25#include <asm/i8259.h>
26
27/*
28 * This is the 'legacy' 8259A Programmable Interrupt Controller,
29 * present in the majority of PC/AT boxes.
30 * plus some generic x86 specific things if generic specifics makes
31 * any sense at all.
32 */
33static void init_8259A(int auto_eoi);
34
35static int i8259A_auto_eoi;
36DEFINE_RAW_SPINLOCK(i8259A_lock);
37
38/*
39 * 8259A PIC functions to handle ISA devices:
40 */
41
42/*
43 * This contains the irq mask for both 8259A irq controllers,
44 */
45unsigned int cached_irq_mask = 0xffff;
46
47/*
48 * Not all IRQs can be routed through the IO-APIC, eg. on certain (older)
49 * boards the timer interrupt is not really connected to any IO-APIC pin,
50 * it's fed to the master 8259A's IR0 line only.
51 *
52 * Any '1' bit in this mask means the IRQ is routed through the IO-APIC.
53 * this 'mixed mode' IRQ handling costs nothing because it's only used
54 * at IRQ setup time.
55 */
56unsigned long io_apic_irqs;
57
58static void mask_8259A_irq(unsigned int irq)
59{
60 unsigned int mask = 1 << irq;
61 unsigned long flags;
62
63 raw_spin_lock_irqsave(&i8259A_lock, flags);
64 cached_irq_mask |= mask;
65 if (irq & 8)
66 outb(cached_slave_mask, PIC_SLAVE_IMR);
67 else
68 outb(cached_master_mask, PIC_MASTER_IMR);
69 raw_spin_unlock_irqrestore(&i8259A_lock, flags);
70}
71
72static void disable_8259A_irq(struct irq_data *data)
73{
74 mask_8259A_irq(data->irq);
75}
76
77static void unmask_8259A_irq(unsigned int irq)
78{
79 unsigned int mask = ~(1 << irq);
80 unsigned long flags;
81
82 raw_spin_lock_irqsave(&i8259A_lock, flags);
83 cached_irq_mask &= mask;
84 if (irq & 8)
85 outb(cached_slave_mask, PIC_SLAVE_IMR);
86 else
87 outb(cached_master_mask, PIC_MASTER_IMR);
88 raw_spin_unlock_irqrestore(&i8259A_lock, flags);
89}
90
91static void enable_8259A_irq(struct irq_data *data)
92{
93 unmask_8259A_irq(data->irq);
94}
95
96static int i8259A_irq_pending(unsigned int irq)
97{
98 unsigned int mask = 1<<irq;
99 unsigned long flags;
100 int ret;
101
102 raw_spin_lock_irqsave(&i8259A_lock, flags);
103 if (irq < 8)
104 ret = inb(PIC_MASTER_CMD) & mask;
105 else
106 ret = inb(PIC_SLAVE_CMD) & (mask >> 8);
107 raw_spin_unlock_irqrestore(&i8259A_lock, flags);
108
109 return ret;
110}
111
112static void make_8259A_irq(unsigned int irq)
113{
114 disable_irq_nosync(irq);
115 io_apic_irqs &= ~(1<<irq);
116 irq_set_chip_and_handler(irq, &i8259A_chip, handle_level_irq);
117 irq_set_status_flags(irq, IRQ_LEVEL);
118 enable_irq(irq);
119 lapic_assign_legacy_vector(irq, true);
120}
121
122/*
123 * This function assumes to be called rarely. Switching between
124 * 8259A registers is slow.
125 * This has to be protected by the irq controller spinlock
126 * before being called.
127 */
128static inline int i8259A_irq_real(unsigned int irq)
129{
130 int value;
131 int irqmask = 1<<irq;
132
133 if (irq < 8) {
134 outb(0x0B, PIC_MASTER_CMD); /* ISR register */
135 value = inb(PIC_MASTER_CMD) & irqmask;
136 outb(0x0A, PIC_MASTER_CMD); /* back to the IRR register */
137 return value;
138 }
139 outb(0x0B, PIC_SLAVE_CMD); /* ISR register */
140 value = inb(PIC_SLAVE_CMD) & (irqmask >> 8);
141 outb(0x0A, PIC_SLAVE_CMD); /* back to the IRR register */
142 return value;
143}
144
145/*
146 * Careful! The 8259A is a fragile beast, it pretty
147 * much _has_ to be done exactly like this (mask it
148 * first, _then_ send the EOI, and the order of EOI
149 * to the two 8259s is important!
150 */
151static void mask_and_ack_8259A(struct irq_data *data)
152{
153 unsigned int irq = data->irq;
154 unsigned int irqmask = 1 << irq;
155 unsigned long flags;
156
157 raw_spin_lock_irqsave(&i8259A_lock, flags);
158 /*
159 * Lightweight spurious IRQ detection. We do not want
160 * to overdo spurious IRQ handling - it's usually a sign
161 * of hardware problems, so we only do the checks we can
162 * do without slowing down good hardware unnecessarily.
163 *
164 * Note that IRQ7 and IRQ15 (the two spurious IRQs
165 * usually resulting from the 8259A-1|2 PICs) occur
166 * even if the IRQ is masked in the 8259A. Thus we
167 * can check spurious 8259A IRQs without doing the
168 * quite slow i8259A_irq_real() call for every IRQ.
169 * This does not cover 100% of spurious interrupts,
170 * but should be enough to warn the user that there
171 * is something bad going on ...
172 */
173 if (cached_irq_mask & irqmask)
174 goto spurious_8259A_irq;
175 cached_irq_mask |= irqmask;
176
177handle_real_irq:
178 if (irq & 8) {
179 inb(PIC_SLAVE_IMR); /* DUMMY - (do we need this?) */
180 outb(cached_slave_mask, PIC_SLAVE_IMR);
181 /* 'Specific EOI' to slave */
182 outb(0x60+(irq&7), PIC_SLAVE_CMD);
183 /* 'Specific EOI' to master-IRQ2 */
184 outb(0x60+PIC_CASCADE_IR, PIC_MASTER_CMD);
185 } else {
186 inb(PIC_MASTER_IMR); /* DUMMY - (do we need this?) */
187 outb(cached_master_mask, PIC_MASTER_IMR);
188 outb(0x60+irq, PIC_MASTER_CMD); /* 'Specific EOI to master */
189 }
190 raw_spin_unlock_irqrestore(&i8259A_lock, flags);
191 return;
192
193spurious_8259A_irq:
194 /*
195 * this is the slow path - should happen rarely.
196 */
197 if (i8259A_irq_real(irq))
198 /*
199 * oops, the IRQ _is_ in service according to the
200 * 8259A - not spurious, go handle it.
201 */
202 goto handle_real_irq;
203
204 {
205 static int spurious_irq_mask;
206 /*
207 * At this point we can be sure the IRQ is spurious,
208 * lets ACK and report it. [once per IRQ]
209 */
210 if (!(spurious_irq_mask & irqmask)) {
211 printk_deferred(KERN_DEBUG
212 "spurious 8259A interrupt: IRQ%d.\n", irq);
213 spurious_irq_mask |= irqmask;
214 }
215 atomic_inc(&irq_err_count);
216 /*
217 * Theoretically we do not have to handle this IRQ,
218 * but in Linux this does not cause problems and is
219 * simpler for us.
220 */
221 goto handle_real_irq;
222 }
223}
224
225struct irq_chip i8259A_chip = {
226 .name = "XT-PIC",
227 .irq_mask = disable_8259A_irq,
228 .irq_disable = disable_8259A_irq,
229 .irq_unmask = enable_8259A_irq,
230 .irq_mask_ack = mask_and_ack_8259A,
231};
232
233static char irq_trigger[2];
234/**
235 * ELCR registers (0x4d0, 0x4d1) control edge/level of IRQ
236 */
237static void restore_ELCR(char *trigger)
238{
239 outb(trigger[0], PIC_ELCR1);
240 outb(trigger[1], PIC_ELCR2);
241}
242
243static void save_ELCR(char *trigger)
244{
245 /* IRQ 0,1,2,8,13 are marked as reserved */
246 trigger[0] = inb(PIC_ELCR1) & 0xF8;
247 trigger[1] = inb(PIC_ELCR2) & 0xDE;
248}
249
250static void i8259A_resume(void)
251{
252 init_8259A(i8259A_auto_eoi);
253 restore_ELCR(irq_trigger);
254}
255
256static int i8259A_suspend(void)
257{
258 save_ELCR(irq_trigger);
259 return 0;
260}
261
262static void i8259A_shutdown(void)
263{
264 /* Put the i8259A into a quiescent state that
265 * the kernel initialization code can get it
266 * out of.
267 */
268 outb(0xff, PIC_MASTER_IMR); /* mask all of 8259A-1 */
269 outb(0xff, PIC_SLAVE_IMR); /* mask all of 8259A-2 */
270}
271
272static struct syscore_ops i8259_syscore_ops = {
273 .suspend = i8259A_suspend,
274 .resume = i8259A_resume,
275 .shutdown = i8259A_shutdown,
276};
277
278static void mask_8259A(void)
279{
280 unsigned long flags;
281
282 raw_spin_lock_irqsave(&i8259A_lock, flags);
283
284 outb(0xff, PIC_MASTER_IMR); /* mask all of 8259A-1 */
285 outb(0xff, PIC_SLAVE_IMR); /* mask all of 8259A-2 */
286
287 raw_spin_unlock_irqrestore(&i8259A_lock, flags);
288}
289
290static void unmask_8259A(void)
291{
292 unsigned long flags;
293
294 raw_spin_lock_irqsave(&i8259A_lock, flags);
295
296 outb(cached_master_mask, PIC_MASTER_IMR); /* restore master IRQ mask */
297 outb(cached_slave_mask, PIC_SLAVE_IMR); /* restore slave IRQ mask */
298
299 raw_spin_unlock_irqrestore(&i8259A_lock, flags);
300}
301
302static int probe_8259A(void)
303{
304 unsigned long flags;
305 unsigned char probe_val = ~(1 << PIC_CASCADE_IR);
306 unsigned char new_val;
307 /*
308 * Check to see if we have a PIC.
309 * Mask all except the cascade and read
310 * back the value we just wrote. If we don't
311 * have a PIC, we will read 0xff as opposed to the
312 * value we wrote.
313 */
314 raw_spin_lock_irqsave(&i8259A_lock, flags);
315
316 outb(0xff, PIC_SLAVE_IMR); /* mask all of 8259A-2 */
317 outb(probe_val, PIC_MASTER_IMR);
318 new_val = inb(PIC_MASTER_IMR);
319 if (new_val != probe_val) {
320 printk(KERN_INFO "Using NULL legacy PIC\n");
321 legacy_pic = &null_legacy_pic;
322 }
323
324 raw_spin_unlock_irqrestore(&i8259A_lock, flags);
325 return nr_legacy_irqs();
326}
327
328static void init_8259A(int auto_eoi)
329{
330 unsigned long flags;
331
332 i8259A_auto_eoi = auto_eoi;
333
334 raw_spin_lock_irqsave(&i8259A_lock, flags);
335
336 outb(0xff, PIC_MASTER_IMR); /* mask all of 8259A-1 */
337
338 /*
339 * outb_pic - this has to work on a wide range of PC hardware.
340 */
341 outb_pic(0x11, PIC_MASTER_CMD); /* ICW1: select 8259A-1 init */
342
343 /* ICW2: 8259A-1 IR0-7 mapped to ISA_IRQ_VECTOR(0) */
344 outb_pic(ISA_IRQ_VECTOR(0), PIC_MASTER_IMR);
345
346 /* 8259A-1 (the master) has a slave on IR2 */
347 outb_pic(1U << PIC_CASCADE_IR, PIC_MASTER_IMR);
348
349 if (auto_eoi) /* master does Auto EOI */
350 outb_pic(MASTER_ICW4_DEFAULT | PIC_ICW4_AEOI, PIC_MASTER_IMR);
351 else /* master expects normal EOI */
352 outb_pic(MASTER_ICW4_DEFAULT, PIC_MASTER_IMR);
353
354 outb_pic(0x11, PIC_SLAVE_CMD); /* ICW1: select 8259A-2 init */
355
356 /* ICW2: 8259A-2 IR0-7 mapped to ISA_IRQ_VECTOR(8) */
357 outb_pic(ISA_IRQ_VECTOR(8), PIC_SLAVE_IMR);
358 /* 8259A-2 is a slave on master's IR2 */
359 outb_pic(PIC_CASCADE_IR, PIC_SLAVE_IMR);
360 /* (slave's support for AEOI in flat mode is to be investigated) */
361 outb_pic(SLAVE_ICW4_DEFAULT, PIC_SLAVE_IMR);
362
363 if (auto_eoi)
364 /*
365 * In AEOI mode we just have to mask the interrupt
366 * when acking.
367 */
368 i8259A_chip.irq_mask_ack = disable_8259A_irq;
369 else
370 i8259A_chip.irq_mask_ack = mask_and_ack_8259A;
371
372 udelay(100); /* wait for 8259A to initialize */
373
374 outb(cached_master_mask, PIC_MASTER_IMR); /* restore master IRQ mask */
375 outb(cached_slave_mask, PIC_SLAVE_IMR); /* restore slave IRQ mask */
376
377 raw_spin_unlock_irqrestore(&i8259A_lock, flags);
378}
379
380/*
381 * make i8259 a driver so that we can select pic functions at run time. the goal
382 * is to make x86 binary compatible among pc compatible and non-pc compatible
383 * platforms, such as x86 MID.
384 */
385
386static void legacy_pic_noop(void) { };
387static void legacy_pic_uint_noop(unsigned int unused) { };
388static void legacy_pic_int_noop(int unused) { };
389static int legacy_pic_irq_pending_noop(unsigned int irq)
390{
391 return 0;
392}
393static int legacy_pic_probe(void)
394{
395 return 0;
396}
397
398struct legacy_pic null_legacy_pic = {
399 .nr_legacy_irqs = 0,
400 .chip = &dummy_irq_chip,
401 .mask = legacy_pic_uint_noop,
402 .unmask = legacy_pic_uint_noop,
403 .mask_all = legacy_pic_noop,
404 .restore_mask = legacy_pic_noop,
405 .init = legacy_pic_int_noop,
406 .probe = legacy_pic_probe,
407 .irq_pending = legacy_pic_irq_pending_noop,
408 .make_irq = legacy_pic_uint_noop,
409};
410
411static struct legacy_pic default_legacy_pic = {
412 .nr_legacy_irqs = NR_IRQS_LEGACY,
413 .chip = &i8259A_chip,
414 .mask = mask_8259A_irq,
415 .unmask = unmask_8259A_irq,
416 .mask_all = mask_8259A,
417 .restore_mask = unmask_8259A,
418 .init = init_8259A,
419 .probe = probe_8259A,
420 .irq_pending = i8259A_irq_pending,
421 .make_irq = make_8259A_irq,
422};
423
424struct legacy_pic *legacy_pic = &default_legacy_pic;
425EXPORT_SYMBOL(legacy_pic);
426
427static int __init i8259A_init_ops(void)
428{
429 if (legacy_pic == &default_legacy_pic)
430 register_syscore_ops(&i8259_syscore_ops);
431
432 return 0;
433}
434
435device_initcall(i8259A_init_ops);