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 */
31 static void init_8259A(int auto_eoi);
32
33 static int i8259A_auto_eoi;
34 DEFINE_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 */
43 unsigned 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 */
54 unsigned long io_apic_irqs;
55
mask_8259A_irq(unsigned int irq)56 static 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
disable_8259A_irq(struct irq_data * data)70 static void disable_8259A_irq(struct irq_data *data)
71 {
72 mask_8259A_irq(data->irq);
73 }
74
unmask_8259A_irq(unsigned int irq)75 static 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
enable_8259A_irq(struct irq_data * data)89 static void enable_8259A_irq(struct irq_data *data)
90 {
91 unmask_8259A_irq(data->irq);
92 }
93
i8259A_irq_pending(unsigned int irq)94 static 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
make_8259A_irq(unsigned int irq)110 static 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 */
i8259A_irq_real(unsigned int irq)125 static 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 */
mask_and_ack_8259A(struct irq_data * data)148 static 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
174 handle_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
190 spurious_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
222 struct 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
230 static char irq_trigger[2];
231 /**
232 * ELCR registers (0x4d0, 0x4d1) control edge/level of IRQ
233 */
restore_ELCR(char * trigger)234 static void restore_ELCR(char *trigger)
235 {
236 outb(trigger[0], 0x4d0);
237 outb(trigger[1], 0x4d1);
238 }
239
save_ELCR(char * trigger)240 static 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
i8259A_resume(void)247 static void i8259A_resume(void)
248 {
249 init_8259A(i8259A_auto_eoi);
250 restore_ELCR(irq_trigger);
251 }
252
i8259A_suspend(void)253 static int i8259A_suspend(void)
254 {
255 save_ELCR(irq_trigger);
256 return 0;
257 }
258
i8259A_shutdown(void)259 static 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-2 */
267 }
268
269 static struct syscore_ops i8259_syscore_ops = {
270 .suspend = i8259A_suspend,
271 .resume = i8259A_resume,
272 .shutdown = i8259A_shutdown,
273 };
274
mask_8259A(void)275 static 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
unmask_8259A(void)287 static 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
init_8259A(int auto_eoi)299 static 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
legacy_pic_noop(void)359 static void legacy_pic_noop(void) { };
legacy_pic_uint_noop(unsigned int unused)360 static void legacy_pic_uint_noop(unsigned int unused) { };
legacy_pic_int_noop(int unused)361 static void legacy_pic_int_noop(int unused) { };
legacy_pic_irq_pending_noop(unsigned int irq)362 static int legacy_pic_irq_pending_noop(unsigned int irq)
363 {
364 return 0;
365 }
366
367 struct 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
379 struct 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
391 struct legacy_pic *legacy_pic = &default_legacy_pic;
392
i8259A_init_ops(void)393 static 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
401 device_initcall(i8259A_init_ops);
402