]> Git Repo - qemu.git/blame - hw/i8259.c
fixed very unlikely irq bug
[qemu.git] / hw / i8259.c
CommitLineData
80cabfad
FB
1/*
2 * QEMU 8259 interrupt controller emulation
3 *
4 * Copyright (c) 2003-2004 Fabrice Bellard
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
80cabfad
FB
24#include "vl.h"
25
26/* debug PIC */
27//#define DEBUG_PIC
28
b41a2cd1
FB
29//#define DEBUG_IRQ_LATENCY
30
80cabfad
FB
31typedef struct PicState {
32 uint8_t last_irr; /* edge detection */
33 uint8_t irr; /* interrupt request register */
34 uint8_t imr; /* interrupt mask register */
35 uint8_t isr; /* interrupt service register */
36 uint8_t priority_add; /* highest irq priority */
37 uint8_t irq_base;
38 uint8_t read_reg_select;
39 uint8_t poll;
40 uint8_t special_mask;
41 uint8_t init_state;
42 uint8_t auto_eoi;
43 uint8_t rotate_on_auto_eoi;
44 uint8_t special_fully_nested_mode;
45 uint8_t init4; /* true if 4 byte init */
46} PicState;
47
48/* 0 is master pic, 1 is slave pic */
ba91cd80
FB
49static PicState pics[2];
50static int pic_irq_requested;
80cabfad
FB
51
52/* set irq level. If an edge is detected, then the IRR is set to 1 */
53static inline void pic_set_irq1(PicState *s, int irq, int level)
54{
55 int mask;
56 mask = 1 << irq;
57 if (level) {
58 if ((s->last_irr & mask) == 0)
59 s->irr |= mask;
60 s->last_irr |= mask;
61 } else {
62 s->last_irr &= ~mask;
63 }
64}
65
66/* return the highest priority found in mask (highest = smallest
67 number). Return 8 if no irq */
68static inline int get_priority(PicState *s, int mask)
69{
70 int priority;
71 if (mask == 0)
72 return 8;
73 priority = 0;
74 while ((mask & (1 << ((priority + s->priority_add) & 7))) == 0)
75 priority++;
76 return priority;
77}
78
79/* return the pic wanted interrupt. return -1 if none */
80static int pic_get_irq(PicState *s)
81{
82 int mask, cur_priority, priority;
83
84 mask = s->irr & ~s->imr;
85 priority = get_priority(s, mask);
86 if (priority == 8)
87 return -1;
88 /* compute current priority. If special fully nested mode on the
89 master, the IRQ coming from the slave is not taken into account
90 for the priority computation. */
91 mask = s->isr;
92 if (s->special_fully_nested_mode && s == &pics[0])
93 mask &= ~(1 << 2);
94 cur_priority = get_priority(s, mask);
95 if (priority < cur_priority) {
96 /* higher priority found: an irq should be generated */
97 return (priority + s->priority_add) & 7;
98 } else {
99 return -1;
100 }
101}
102
103/* raise irq to CPU if necessary. must be called every time the active
104 irq may change */
b0a21b53 105static void pic_update_irq(void)
80cabfad
FB
106{
107 int irq2, irq;
108
109 /* first look at slave pic */
110 irq2 = pic_get_irq(&pics[1]);
111 if (irq2 >= 0) {
112 /* if irq request by slave pic, signal master PIC */
113 pic_set_irq1(&pics[0], 2, 1);
114 pic_set_irq1(&pics[0], 2, 0);
115 }
116 /* look at requested irq */
117 irq = pic_get_irq(&pics[0]);
118 if (irq >= 0) {
119 if (irq == 2) {
120 /* from slave pic */
121 pic_irq_requested = 8 + irq2;
122 } else {
123 /* from master pic */
124 pic_irq_requested = irq;
125 }
126#if defined(DEBUG_PIC)
127 {
128 int i;
129 for(i = 0; i < 2; i++) {
130 printf("pic%d: imr=%x irr=%x padd=%d\n",
131 i, pics[i].imr, pics[i].irr, pics[i].priority_add);
132
133 }
134 }
135 printf("pic: cpu_interrupt req=%d\n", pic_irq_requested);
136#endif
137 cpu_interrupt(cpu_single_env, CPU_INTERRUPT_HARD);
138 }
139}
140
141#ifdef DEBUG_IRQ_LATENCY
142int64_t irq_time[16];
80cabfad
FB
143#endif
144#if defined(DEBUG_PIC)
145int irq_level[16];
146#endif
147
148void pic_set_irq(int irq, int level)
149{
150#if defined(DEBUG_PIC)
151 if (level != irq_level[irq]) {
152 printf("pic_set_irq: irq=%d level=%d\n", irq, level);
153 irq_level[irq] = level;
154 }
155#endif
156#ifdef DEBUG_IRQ_LATENCY
157 if (level) {
158 irq_time[irq] = cpu_get_ticks();
159 }
160#endif
161 pic_set_irq1(&pics[irq >> 3], irq & 7, level);
162 pic_update_irq();
163}
164
165/* acknowledge interrupt 'irq' */
166static inline void pic_intack(PicState *s, int irq)
167{
168 if (s->auto_eoi) {
169 if (s->rotate_on_auto_eoi)
170 s->priority_add = (irq + 1) & 7;
171 } else {
172 s->isr |= (1 << irq);
173 }
174 s->irr &= ~(1 << irq);
175}
176
a541f297 177int cpu_get_pic_interrupt(CPUState *env)
80cabfad
FB
178{
179 int irq, irq2, intno;
180
181 /* signal the pic that the irq was acked by the CPU */
182 irq = pic_irq_requested;
183#ifdef DEBUG_IRQ_LATENCY
184 printf("IRQ%d latency=%0.3fus\n",
185 irq,
186 (double)(cpu_get_ticks() - irq_time[irq]) * 1000000.0 / ticks_per_sec);
187#endif
188#if defined(DEBUG_PIC)
189 printf("pic_interrupt: irq=%d\n", irq);
190#endif
191
192 if (irq >= 8) {
193 irq2 = irq & 7;
194 pic_intack(&pics[1], irq2);
195 irq = 2;
196 intno = pics[1].irq_base + irq2;
197 } else {
198 intno = pics[0].irq_base + irq;
199 }
200 pic_intack(&pics[0], irq);
ba91cd80 201 pic_update_irq();
80cabfad
FB
202 return intno;
203}
204
b41a2cd1 205static void pic_ioport_write(void *opaque, uint32_t addr, uint32_t val)
80cabfad 206{
b41a2cd1 207 PicState *s = opaque;
80cabfad
FB
208 int priority, cmd, irq;
209
210#ifdef DEBUG_PIC
211 printf("pic_write: addr=0x%02x val=0x%02x\n", addr, val);
212#endif
80cabfad
FB
213 addr &= 1;
214 if (addr == 0) {
215 if (val & 0x10) {
216 /* init */
217 memset(s, 0, sizeof(PicState));
218 s->init_state = 1;
219 s->init4 = val & 1;
220 if (val & 0x02)
221 hw_error("single mode not supported");
222 if (val & 0x08)
223 hw_error("level sensitive irq not supported");
224 } else if (val & 0x08) {
225 if (val & 0x04)
226 s->poll = 1;
227 if (val & 0x02)
228 s->read_reg_select = val & 1;
229 if (val & 0x40)
230 s->special_mask = (val >> 5) & 1;
231 } else {
232 cmd = val >> 5;
233 switch(cmd) {
234 case 0:
235 case 4:
236 s->rotate_on_auto_eoi = cmd >> 2;
237 break;
238 case 1: /* end of interrupt */
239 case 5:
240 priority = get_priority(s, s->isr);
241 if (priority != 8) {
242 irq = (priority + s->priority_add) & 7;
243 s->isr &= ~(1 << irq);
244 if (cmd == 5)
245 s->priority_add = (irq + 1) & 7;
246 pic_update_irq();
247 }
248 break;
249 case 3:
250 irq = val & 7;
251 s->isr &= ~(1 << irq);
252 pic_update_irq();
253 break;
254 case 6:
255 s->priority_add = (val + 1) & 7;
256 pic_update_irq();
257 break;
258 case 7:
259 irq = val & 7;
260 s->isr &= ~(1 << irq);
261 s->priority_add = (irq + 1) & 7;
262 pic_update_irq();
263 break;
264 default:
265 /* no operation */
266 break;
267 }
268 }
269 } else {
270 switch(s->init_state) {
271 case 0:
272 /* normal mode */
273 s->imr = val;
274 pic_update_irq();
275 break;
276 case 1:
277 s->irq_base = val & 0xf8;
278 s->init_state = 2;
279 break;
280 case 2:
281 if (s->init4) {
282 s->init_state = 3;
283 } else {
284 s->init_state = 0;
285 }
286 break;
287 case 3:
288 s->special_fully_nested_mode = (val >> 4) & 1;
289 s->auto_eoi = (val >> 1) & 1;
290 s->init_state = 0;
291 break;
292 }
293 }
294}
295
296static uint32_t pic_poll_read (PicState *s, uint32_t addr1)
297{
298 int ret;
299
300 ret = pic_get_irq(s);
301 if (ret >= 0) {
302 if (addr1 >> 7) {
303 pics[0].isr &= ~(1 << 2);
304 pics[0].irr &= ~(1 << 2);
305 }
306 s->irr &= ~(1 << ret);
307 s->isr &= ~(1 << ret);
308 if (addr1 >> 7 || ret != 2)
309 pic_update_irq();
310 } else {
311 ret = 0x07;
312 pic_update_irq();
313 }
314
315 return ret;
316}
317
b41a2cd1 318static uint32_t pic_ioport_read(void *opaque, uint32_t addr1)
80cabfad 319{
b41a2cd1 320 PicState *s = opaque;
80cabfad
FB
321 unsigned int addr;
322 int ret;
323
324 addr = addr1;
80cabfad
FB
325 addr &= 1;
326 if (s->poll) {
327 ret = pic_poll_read(s, addr1);
328 s->poll = 0;
329 } else {
330 if (addr == 0) {
331 if (s->read_reg_select)
332 ret = s->isr;
333 else
334 ret = s->irr;
335 } else {
336 ret = s->imr;
337 }
338 }
339#ifdef DEBUG_PIC
340 printf("pic_read: addr=0x%02x val=0x%02x\n", addr1, ret);
341#endif
342 return ret;
343}
344
345/* memory mapped interrupt status */
346uint32_t pic_intack_read(CPUState *env)
347{
348 int ret;
349
350 ret = pic_poll_read(&pics[0], 0x00);
351 if (ret == 2)
352 ret = pic_poll_read(&pics[1], 0x80) + 8;
353 /* Prepare for ISR read */
354 pics[0].read_reg_select = 1;
355
356 return ret;
357}
358
b0a21b53
FB
359static void pic_save(QEMUFile *f, void *opaque)
360{
361 PicState *s = opaque;
362
363 qemu_put_8s(f, &s->last_irr);
364 qemu_put_8s(f, &s->irr);
365 qemu_put_8s(f, &s->imr);
366 qemu_put_8s(f, &s->isr);
367 qemu_put_8s(f, &s->priority_add);
368 qemu_put_8s(f, &s->irq_base);
369 qemu_put_8s(f, &s->read_reg_select);
370 qemu_put_8s(f, &s->poll);
371 qemu_put_8s(f, &s->special_mask);
372 qemu_put_8s(f, &s->init_state);
373 qemu_put_8s(f, &s->auto_eoi);
374 qemu_put_8s(f, &s->rotate_on_auto_eoi);
375 qemu_put_8s(f, &s->special_fully_nested_mode);
376 qemu_put_8s(f, &s->init4);
377}
378
379static int pic_load(QEMUFile *f, void *opaque, int version_id)
380{
381 PicState *s = opaque;
382
383 if (version_id != 1)
384 return -EINVAL;
385
386 qemu_get_8s(f, &s->last_irr);
387 qemu_get_8s(f, &s->irr);
388 qemu_get_8s(f, &s->imr);
389 qemu_get_8s(f, &s->isr);
390 qemu_get_8s(f, &s->priority_add);
391 qemu_get_8s(f, &s->irq_base);
392 qemu_get_8s(f, &s->read_reg_select);
393 qemu_get_8s(f, &s->poll);
394 qemu_get_8s(f, &s->special_mask);
395 qemu_get_8s(f, &s->init_state);
396 qemu_get_8s(f, &s->auto_eoi);
397 qemu_get_8s(f, &s->rotate_on_auto_eoi);
398 qemu_get_8s(f, &s->special_fully_nested_mode);
399 qemu_get_8s(f, &s->init4);
400 return 0;
401}
402
403/* XXX: add generic master/slave system */
404static void pic_init1(int io_addr, PicState *s)
405{
406 register_ioport_write(io_addr, 2, 1, pic_ioport_write, s);
407 register_ioport_read(io_addr, 2, 1, pic_ioport_read, s);
408
409 register_savevm("i8259", io_addr, 1, pic_save, pic_load, s);
410}
411
ba91cd80
FB
412void pic_info(void)
413{
414 int i;
415 PicState *s;
416
417 for(i=0;i<2;i++) {
418 s = &pics[i];
419 term_printf("pic%d: irr=%02x imr=%02x isr=%02x hprio=%d irq_base=%02x rr_sel=%d\n",
420 i, s->irr, s->imr, s->isr, s->priority_add, s->irq_base, s->read_reg_select);
421 }
422}
423
424
80cabfad
FB
425void pic_init(void)
426{
b0a21b53
FB
427 pic_init1(0x20, &pics[0]);
428 pic_init1(0xa0, &pics[1]);
80cabfad
FB
429}
430
This page took 0.065809 seconds and 4 git commands to generate.