hw/intc/i8259.c

   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  */
  24 #include "qemu/osdep.h"
  25 #include "hw/hw.h"
  26 #include "hw/i386/pc.h"
  27 #include "hw/isa/isa.h"
  28 #include "qemu/timer.h"
  29 #include "qemu/log.h"
  30 #include "hw/isa/i8259_internal.h"
  31 #include "trace.h"
  32
  33 /* debug PIC */
  34 //#define DEBUG_PIC
  35
  36 //#define DEBUG_IRQ_LATENCY
  37
  38 #define TYPE_I8259 "isa-i8259"
  39 #define PIC_CLASS(class) OBJECT_CLASS_CHECK(PICClass, (class), TYPE_I8259)
  40 #define PIC_GET_CLASS(obj) OBJECT_GET_CLASS(PICClass, (obj), TYPE_I8259)
  41
  42 /**
  43  * PICClass:
  44  * @parent_realize: The parent's realizefn.
  45  */
  46 typedef struct PICClass {
  47     PICCommonClass parent_class;
  48
  49     DeviceRealize parent_realize;
  50 } PICClass;
  51
  52 #ifdef DEBUG_IRQ_LATENCY
  53 static int64_t irq_time[16];
  54 #endif
  55 DeviceState *isa_pic;
  56 static PICCommonState *slave_pic;
  57
  58 /* return the highest priority found in mask (highest = smallest
  59    number). Return 8 if no irq */
  60 static int get_priority(PICCommonState *s, int mask)
  61 {
  62     int priority;
  63
  64     if (mask == 0) {
  65         return 8;
  66     }
  67     priority = 0;
  68     while ((mask & (1 << ((priority + s->priority_add) & 7))) == 0) {
  69         priority++;
  70     }
  71     return priority;
  72 }
  73
  74 /* return the pic wanted interrupt. return -1 if none */
  75 static int pic_get_irq(PICCommonState *s)
  76 {
  77     int mask, cur_priority, priority;
  78
  79     mask = s->irr & ~s->imr;
  80     priority = get_priority(s, mask);
  81     if (priority == 8) {
  82         return -1;
  83     }
  84     /* compute current priority. If special fully nested mode on the
  85        master, the IRQ coming from the slave is not taken into account
  86        for the priority computation. */
  87     mask = s->isr;
  88     if (s->special_mask) {
  89         mask &= ~s->imr;
  90     }
  91     if (s->special_fully_nested_mode && s->master) {
  92         mask &= ~(1 << 2);
  93     }
  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 /* Update INT output. Must be called every time the output may have changed. */
 104 static void pic_update_irq(PICCommonState *s)
 105 {
 106     int irq;
 107
 108     irq = pic_get_irq(s);
 109     if (irq >= 0) {
 110         trace_pic_update_irq(s->master, s->imr, s->irr, s->priority_add);
 111         qemu_irq_raise(s->int_out[0]);
 112     } else {
 113         qemu_irq_lower(s->int_out[0]);
 114     }
 115 }
 116
 117 /* set irq level. If an edge is detected, then the IRR is set to 1 */
 118 static void pic_set_irq(void *opaque, int irq, int level)
 119 {
 120     PICCommonState *s = opaque;
 121     int mask = 1 << irq;
 122     int irq_index = s->master ? irq : irq + 8;
 123
 124     trace_pic_set_irq(s->master, irq, level);
 125     pic_stat_update_irq(irq_index, level);
 126
 127 #ifdef DEBUG_IRQ_LATENCY
 128     if (level) {
 129         irq_time[irq_index] = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
 130     }
 131 #endif
 132
 133     if (s->elcr & mask) {
 134         /* level triggered */
 135         if (level) {
 136             s->irr |= mask;
 137             s->last_irr |= mask;
 138         } else {
 139             s->irr &= ~mask;
 140             s->last_irr &= ~mask;
 141         }
 142     } else {
 143         /* edge triggered */
 144         if (level) {
 145             if ((s->last_irr & mask) == 0) {
 146                 s->irr |= mask;
 147             }
 148             s->last_irr |= mask;
 149         } else {
 150             s->last_irr &= ~mask;
 151         }
 152     }
 153     pic_update_irq(s);
 154 }
 155
 156 /* acknowledge interrupt 'irq' */
 157 static void pic_intack(PICCommonState *s, int irq)
 158 {
 159     if (s->auto_eoi) {
 160         if (s->rotate_on_auto_eoi) {
 161             s->priority_add = (irq + 1) & 7;
 162         }
 163     } else {
 164         s->isr |= (1 << irq);
 165     }
 166     /* We don't clear a level sensitive interrupt here */
 167     if (!(s->elcr & (1 << irq))) {
 168         s->irr &= ~(1 << irq);
 169     }
 170     pic_update_irq(s);
 171 }
 172
 173 int pic_read_irq(DeviceState *d)
 174 {
 175     PICCommonState *s = PIC_COMMON(d);
 176     int irq, irq2, intno;
 177
 178     irq = pic_get_irq(s);
 179     if (irq >= 0) {
 180         if (irq == 2) {
 181             irq2 = pic_get_irq(slave_pic);
 182             if (irq2 >= 0) {
 183                 pic_intack(slave_pic, irq2);
 184             } else {
 185                 /* spurious IRQ on slave controller */
 186                 irq2 = 7;
 187             }
 188             intno = slave_pic->irq_base + irq2;
 189         } else {
 190             intno = s->irq_base + irq;
 191         }
 192         pic_intack(s, irq);
 193     } else {
 194         /* spurious IRQ on host controller */
 195         irq = 7;
 196         intno = s->irq_base + irq;
 197     }
 198
 199     if (irq == 2) {
 200         irq = irq2 + 8;
 201     }
 202
 203 #ifdef DEBUG_IRQ_LATENCY
 204     printf("IRQ%d latency=%0.3fus\n",
 205            irq,
 206            (double)(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) -
 207                     irq_time[irq]) * 1000000.0 / NANOSECONDS_PER_SECOND);
 208 #endif
 209
 210     trace_pic_interrupt(irq, intno);
 211     return intno;
 212 }
 213
 214 static void pic_init_reset(PICCommonState *s)
 215 {
 216     pic_reset_common(s);
 217     pic_update_irq(s);
 218 }
 219
 220 static void pic_reset(DeviceState *dev)
 221 {
 222     PICCommonState *s = PIC_COMMON(dev);
 223
 224     s->elcr = 0;
 225     pic_init_reset(s);
 226 }
 227
 228 static void pic_ioport_write(void *opaque, hwaddr addr64,
 229                              uint64_t val64, unsigned size)
 230 {
 231     PICCommonState *s = opaque;
 232     uint32_t addr = addr64;
 233     uint32_t val = val64;
 234     int priority, cmd, irq;
 235
 236     trace_pic_ioport_write(s->master, addr, val);
 237
 238     if (addr == 0) {
 239         if (val & 0x10) {
 240             pic_init_reset(s);
 241             s->init_state = 1;
 242             s->init4 = val & 1;
 243             s->single_mode = val & 2;
 244             if (val & 0x08) {
 245                 qemu_log_mask(LOG_UNIMP,
 246                               "i8259: level sensitive irq not supported\n");
 247             }
 248         } else if (val & 0x08) {
 249             if (val & 0x04) {
 250                 s->poll = 1;
 251             }
 252             if (val & 0x02) {
 253                 s->read_reg_select = val & 1;
 254             }
 255             if (val & 0x40) {
 256                 s->special_mask = (val >> 5) & 1;
 257             }
 258         } else {
 259             cmd = val >> 5;
 260             switch (cmd) {
 261             case 0:
 262             case 4:
 263                 s->rotate_on_auto_eoi = cmd >> 2;
 264                 break;
 265             case 1: /* end of interrupt */
 266             case 5:
 267                 priority = get_priority(s, s->isr);
 268                 if (priority != 8) {
 269                     irq = (priority + s->priority_add) & 7;
 270                     s->isr &= ~(1 << irq);
 271                     if (cmd == 5) {
 272                         s->priority_add = (irq + 1) & 7;
 273                     }
 274                     pic_update_irq(s);
 275                 }
 276                 break;
 277             case 3:
 278                 irq = val & 7;
 279                 s->isr &= ~(1 << irq);
 280                 pic_update_irq(s);
 281                 break;
 282             case 6:
 283                 s->priority_add = (val + 1) & 7;
 284                 pic_update_irq(s);
 285                 break;
 286             case 7:
 287                 irq = val & 7;
 288                 s->isr &= ~(1 << irq);
 289                 s->priority_add = (irq + 1) & 7;
 290                 pic_update_irq(s);
 291                 break;
 292             default:
 293                 /* no operation */
 294                 break;
 295             }
 296         }
 297     } else {
 298         switch (s->init_state) {
 299         case 0:
 300             /* normal mode */
 301             s->imr = val;
 302             pic_update_irq(s);
 303             break;
 304         case 1:
 305             s->irq_base = val & 0xf8;
 306             s->init_state = s->single_mode ? (s->init4 ? 3 : 0) : 2;
 307             break;
 308         case 2:
 309             if (s->init4) {
 310                 s->init_state = 3;
 311             } else {
 312                 s->init_state = 0;
 313             }
 314             break;
 315         case 3:
 316             s->special_fully_nested_mode = (val >> 4) & 1;
 317             s->auto_eoi = (val >> 1) & 1;
 318             s->init_state = 0;
 319             break;
 320         }
 321     }
 322 }
 323
 324 static uint64_t pic_ioport_read(void *opaque, hwaddr addr,
 325                                 unsigned size)
 326 {
 327     PICCommonState *s = opaque;
 328     int ret;
 329
 330     if (s->poll) {
 331         ret = pic_get_irq(s);
 332         if (ret >= 0) {
 333             pic_intack(s, ret);
 334             ret |= 0x80;
 335         } else {
 336             ret = 0;
 337         }
 338         s->poll = 0;
 339     } else {
 340         if (addr == 0) {
 341             if (s->read_reg_select) {
 342                 ret = s->isr;
 343             } else {
 344                 ret = s->irr;
 345             }
 346         } else {
 347             ret = s->imr;
 348         }
 349     }
 350     trace_pic_ioport_read(s->master, addr, ret);
 351     return ret;
 352 }
 353
 354 int pic_get_output(DeviceState *d)
 355 {
 356     PICCommonState *s = PIC_COMMON(d);
 357
 358     return (pic_get_irq(s) >= 0);
 359 }
 360
 361 static void elcr_ioport_write(void *opaque, hwaddr addr,
 362                               uint64_t val, unsigned size)
 363 {
 364     PICCommonState *s = opaque;
 365     s->elcr = val & s->elcr_mask;
 366 }
 367
 368 static uint64_t elcr_ioport_read(void *opaque, hwaddr addr,
 369                                  unsigned size)
 370 {
 371     PICCommonState *s = opaque;
 372     return s->elcr;
 373 }
 374
 375 static const MemoryRegionOps pic_base_ioport_ops = {
 376     .read = pic_ioport_read,
 377     .write = pic_ioport_write,
 378     .impl = {
 379         .min_access_size = 1,
 380         .max_access_size = 1,
 381     },
 382 };
 383
 384 static const MemoryRegionOps pic_elcr_ioport_ops = {
 385     .read = elcr_ioport_read,
 386     .write = elcr_ioport_write,
 387     .impl = {
 388         .min_access_size = 1,
 389         .max_access_size = 1,
 390     },
 391 };
 392
 393 static void pic_realize(DeviceState *dev, Error **errp)
 394 {
 395     PICCommonState *s = PIC_COMMON(dev);
 396     PICClass *pc = PIC_GET_CLASS(dev);
 397
 398     memory_region_init_io(&s->base_io, OBJECT(s), &pic_base_ioport_ops, s,
 399                           "pic", 2);
 400     memory_region_init_io(&s->elcr_io, OBJECT(s), &pic_elcr_ioport_ops, s,
 401                           "elcr", 1);
 402
 403     qdev_init_gpio_out(dev, s->int_out, ARRAY_SIZE(s->int_out));
 404     qdev_init_gpio_in(dev, pic_set_irq, 8);
 405
 406     pc->parent_realize(dev, errp);
 407 }
 408
 409 qemu_irq *i8259_init(ISABus *bus, qemu_irq parent_irq)
 410 {
 411     qemu_irq *irq_set;
 412     DeviceState *dev;
 413     ISADevice *isadev;
 414     int i;
 415
 416     irq_set = g_new0(qemu_irq, ISA_NUM_IRQS);
 417
 418     isadev = i8259_init_chip(TYPE_I8259, bus, true);
 419     dev = DEVICE(isadev);
 420
 421     qdev_connect_gpio_out(dev, 0, parent_irq);
 422     for (i = 0 ; i < 8; i++) {
 423         irq_set[i] = qdev_get_gpio_in(dev, i);
 424     }
 425
 426     isa_pic = dev;
 427
 428     isadev = i8259_init_chip(TYPE_I8259, bus, false);
 429     dev = DEVICE(isadev);
 430
 431     qdev_connect_gpio_out(dev, 0, irq_set[2]);
 432     for (i = 0 ; i < 8; i++) {
 433         irq_set[i + 8] = qdev_get_gpio_in(dev, i);
 434     }
 435
 436     slave_pic = PIC_COMMON(dev);
 437
 438     return irq_set;
 439 }
 440
 441 static void i8259_class_init(ObjectClass *klass, void *data)
 442 {
 443     PICClass *k = PIC_CLASS(klass);
 444     DeviceClass *dc = DEVICE_CLASS(klass);
 445
 446     k->parent_realize = dc->realize;
 447     dc->realize = pic_realize;
 448     dc->reset = pic_reset;
 449 }
 450
 451 static const TypeInfo i8259_info = {
 452     .name       = TYPE_I8259,
 453     .instance_size = sizeof(PICCommonState),
 454     .parent     = TYPE_PIC_COMMON,
 455     .class_init = i8259_class_init,
 456     .class_size = sizeof(PICClass),
 457 };
 458
 459 static void pic_register_types(void)
 460 {
 461     type_register_static(&i8259_info);
 462 }
 463
 464 type_init(pic_register_types)