mos6522.c (15696B)
1/* 2 * QEMU MOS6522 VIA emulation 3 * 4 * Copyright (c) 2004-2007 Fabrice Bellard 5 * Copyright (c) 2007 Jocelyn Mayer 6 * Copyright (c) 2018 Mark Cave-Ayland 7 * 8 * Permission is hereby granted, free of charge, to any person obtaining a copy 9 * of this software and associated documentation files (the "Software"), to deal 10 * in the Software without restriction, including without limitation the rights 11 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 12 * copies of the Software, and to permit persons to whom the Software is 13 * furnished to do so, subject to the following conditions: 14 * 15 * The above copyright notice and this permission notice shall be included in 16 * all copies or substantial portions of the Software. 17 * 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 21 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 23 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 24 * THE SOFTWARE. 25 */ 26 27#include "qemu/osdep.h" 28#include "hw/input/adb.h" 29#include "hw/irq.h" 30#include "hw/misc/mos6522.h" 31#include "hw/qdev-properties.h" 32#include "migration/vmstate.h" 33#include "qemu/timer.h" 34#include "qemu/cutils.h" 35#include "qemu/log.h" 36#include "qemu/module.h" 37#include "trace.h" 38 39/* XXX: implement all timer modes */ 40 41static void mos6522_timer1_update(MOS6522State *s, MOS6522Timer *ti, 42 int64_t current_time); 43static void mos6522_timer2_update(MOS6522State *s, MOS6522Timer *ti, 44 int64_t current_time); 45 46static void mos6522_update_irq(MOS6522State *s) 47{ 48 if (s->ifr & s->ier) { 49 qemu_irq_raise(s->irq); 50 } else { 51 qemu_irq_lower(s->irq); 52 } 53} 54 55static uint64_t get_counter_value(MOS6522State *s, MOS6522Timer *ti) 56{ 57 MOS6522DeviceClass *mdc = MOS6522_GET_CLASS(s); 58 59 if (ti->index == 0) { 60 return mdc->get_timer1_counter_value(s, ti); 61 } else { 62 return mdc->get_timer2_counter_value(s, ti); 63 } 64} 65 66static uint64_t get_load_time(MOS6522State *s, MOS6522Timer *ti) 67{ 68 MOS6522DeviceClass *mdc = MOS6522_GET_CLASS(s); 69 70 if (ti->index == 0) { 71 return mdc->get_timer1_load_time(s, ti); 72 } else { 73 return mdc->get_timer2_load_time(s, ti); 74 } 75} 76 77static unsigned int get_counter(MOS6522State *s, MOS6522Timer *ti) 78{ 79 int64_t d; 80 unsigned int counter; 81 82 d = get_counter_value(s, ti); 83 84 if (ti->index == 0) { 85 /* the timer goes down from latch to -1 (period of latch + 2) */ 86 if (d <= (ti->counter_value + 1)) { 87 counter = (ti->counter_value - d) & 0xffff; 88 } else { 89 counter = (d - (ti->counter_value + 1)) % (ti->latch + 2); 90 counter = (ti->latch - counter) & 0xffff; 91 } 92 } else { 93 counter = (ti->counter_value - d) & 0xffff; 94 } 95 return counter; 96} 97 98static void set_counter(MOS6522State *s, MOS6522Timer *ti, unsigned int val) 99{ 100 trace_mos6522_set_counter(1 + ti->index, val); 101 ti->load_time = get_load_time(s, ti); 102 ti->counter_value = val; 103 if (ti->index == 0) { 104 mos6522_timer1_update(s, ti, ti->load_time); 105 } else { 106 mos6522_timer2_update(s, ti, ti->load_time); 107 } 108} 109 110static int64_t get_next_irq_time(MOS6522State *s, MOS6522Timer *ti, 111 int64_t current_time) 112{ 113 int64_t d, next_time; 114 unsigned int counter; 115 116 if (ti->frequency == 0) { 117 return INT64_MAX; 118 } 119 120 /* current counter value */ 121 d = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - ti->load_time, 122 ti->frequency, NANOSECONDS_PER_SECOND); 123 124 /* the timer goes down from latch to -1 (period of latch + 2) */ 125 if (d <= (ti->counter_value + 1)) { 126 counter = (ti->counter_value - d) & 0xffff; 127 } else { 128 counter = (d - (ti->counter_value + 1)) % (ti->latch + 2); 129 counter = (ti->latch - counter) & 0xffff; 130 } 131 132 /* Note: we consider the irq is raised on 0 */ 133 if (counter == 0xffff) { 134 next_time = d + ti->latch + 1; 135 } else if (counter == 0) { 136 next_time = d + ti->latch + 2; 137 } else { 138 next_time = d + counter; 139 } 140 trace_mos6522_get_next_irq_time(ti->latch, d, next_time - d); 141 next_time = muldiv64(next_time, NANOSECONDS_PER_SECOND, ti->frequency) + 142 ti->load_time; 143 144 if (next_time <= current_time) { 145 next_time = current_time + 1; 146 } 147 return next_time; 148} 149 150static void mos6522_timer1_update(MOS6522State *s, MOS6522Timer *ti, 151 int64_t current_time) 152{ 153 if (!ti->timer) { 154 return; 155 } 156 ti->next_irq_time = get_next_irq_time(s, ti, current_time); 157 if ((s->ier & T1_INT) == 0 || (s->acr & T1MODE) != T1MODE_CONT) { 158 timer_del(ti->timer); 159 } else { 160 timer_mod(ti->timer, ti->next_irq_time); 161 } 162} 163 164static void mos6522_timer2_update(MOS6522State *s, MOS6522Timer *ti, 165 int64_t current_time) 166{ 167 if (!ti->timer) { 168 return; 169 } 170 ti->next_irq_time = get_next_irq_time(s, ti, current_time); 171 if ((s->ier & T2_INT) == 0) { 172 timer_del(ti->timer); 173 } else { 174 timer_mod(ti->timer, ti->next_irq_time); 175 } 176} 177 178static void mos6522_timer1(void *opaque) 179{ 180 MOS6522State *s = opaque; 181 MOS6522Timer *ti = &s->timers[0]; 182 183 mos6522_timer1_update(s, ti, ti->next_irq_time); 184 s->ifr |= T1_INT; 185 mos6522_update_irq(s); 186} 187 188static void mos6522_timer2(void *opaque) 189{ 190 MOS6522State *s = opaque; 191 MOS6522Timer *ti = &s->timers[1]; 192 193 mos6522_timer2_update(s, ti, ti->next_irq_time); 194 s->ifr |= T2_INT; 195 mos6522_update_irq(s); 196} 197 198static void mos6522_set_sr_int(MOS6522State *s) 199{ 200 trace_mos6522_set_sr_int(); 201 s->ifr |= SR_INT; 202 mos6522_update_irq(s); 203} 204 205static uint64_t mos6522_get_counter_value(MOS6522State *s, MOS6522Timer *ti) 206{ 207 return muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - ti->load_time, 208 ti->frequency, NANOSECONDS_PER_SECOND); 209} 210 211static uint64_t mos6522_get_load_time(MOS6522State *s, MOS6522Timer *ti) 212{ 213 uint64_t load_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); 214 215 return load_time; 216} 217 218static void mos6522_portA_write(MOS6522State *s) 219{ 220 qemu_log_mask(LOG_UNIMP, "portA_write unimplemented\n"); 221} 222 223static void mos6522_portB_write(MOS6522State *s) 224{ 225 qemu_log_mask(LOG_UNIMP, "portB_write unimplemented\n"); 226} 227 228uint64_t mos6522_read(void *opaque, hwaddr addr, unsigned size) 229{ 230 MOS6522State *s = opaque; 231 uint32_t val; 232 int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); 233 234 if (now >= s->timers[0].next_irq_time) { 235 mos6522_timer1_update(s, &s->timers[0], now); 236 s->ifr |= T1_INT; 237 } 238 if (now >= s->timers[1].next_irq_time) { 239 mos6522_timer2_update(s, &s->timers[1], now); 240 s->ifr |= T2_INT; 241 } 242 switch (addr) { 243 case VIA_REG_B: 244 val = s->b; 245 break; 246 case VIA_REG_A: 247 qemu_log_mask(LOG_UNIMP, "Read access to register A with handshake"); 248 /* fall through */ 249 case VIA_REG_ANH: 250 val = s->a; 251 break; 252 case VIA_REG_DIRB: 253 val = s->dirb; 254 break; 255 case VIA_REG_DIRA: 256 val = s->dira; 257 break; 258 case VIA_REG_T1CL: 259 val = get_counter(s, &s->timers[0]) & 0xff; 260 s->ifr &= ~T1_INT; 261 mos6522_update_irq(s); 262 break; 263 case VIA_REG_T1CH: 264 val = get_counter(s, &s->timers[0]) >> 8; 265 mos6522_update_irq(s); 266 break; 267 case VIA_REG_T1LL: 268 val = s->timers[0].latch & 0xff; 269 break; 270 case VIA_REG_T1LH: 271 /* XXX: check this */ 272 val = (s->timers[0].latch >> 8) & 0xff; 273 break; 274 case VIA_REG_T2CL: 275 val = get_counter(s, &s->timers[1]) & 0xff; 276 s->ifr &= ~T2_INT; 277 mos6522_update_irq(s); 278 break; 279 case VIA_REG_T2CH: 280 val = get_counter(s, &s->timers[1]) >> 8; 281 break; 282 case VIA_REG_SR: 283 val = s->sr; 284 s->ifr &= ~SR_INT; 285 mos6522_update_irq(s); 286 break; 287 case VIA_REG_ACR: 288 val = s->acr; 289 break; 290 case VIA_REG_PCR: 291 val = s->pcr; 292 break; 293 case VIA_REG_IFR: 294 val = s->ifr; 295 if (s->ifr & s->ier) { 296 val |= 0x80; 297 } 298 break; 299 case VIA_REG_IER: 300 val = s->ier | 0x80; 301 break; 302 default: 303 g_assert_not_reached(); 304 } 305 306 if (addr != VIA_REG_IFR || val != 0) { 307 trace_mos6522_read(addr, val); 308 } 309 310 return val; 311} 312 313void mos6522_write(void *opaque, hwaddr addr, uint64_t val, unsigned size) 314{ 315 MOS6522State *s = opaque; 316 MOS6522DeviceClass *mdc = MOS6522_GET_CLASS(s); 317 318 trace_mos6522_write(addr, val); 319 320 switch (addr) { 321 case VIA_REG_B: 322 s->b = (s->b & ~s->dirb) | (val & s->dirb); 323 mdc->portB_write(s); 324 break; 325 case VIA_REG_A: 326 qemu_log_mask(LOG_UNIMP, "Write access to register A with handshake"); 327 /* fall through */ 328 case VIA_REG_ANH: 329 s->a = (s->a & ~s->dira) | (val & s->dira); 330 mdc->portA_write(s); 331 break; 332 case VIA_REG_DIRB: 333 s->dirb = val; 334 break; 335 case VIA_REG_DIRA: 336 s->dira = val; 337 break; 338 case VIA_REG_T1CL: 339 s->timers[0].latch = (s->timers[0].latch & 0xff00) | val; 340 mos6522_timer1_update(s, &s->timers[0], 341 qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)); 342 break; 343 case VIA_REG_T1CH: 344 s->timers[0].latch = (s->timers[0].latch & 0xff) | (val << 8); 345 s->ifr &= ~T1_INT; 346 set_counter(s, &s->timers[0], s->timers[0].latch); 347 break; 348 case VIA_REG_T1LL: 349 s->timers[0].latch = (s->timers[0].latch & 0xff00) | val; 350 mos6522_timer1_update(s, &s->timers[0], 351 qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)); 352 break; 353 case VIA_REG_T1LH: 354 s->timers[0].latch = (s->timers[0].latch & 0xff) | (val << 8); 355 s->ifr &= ~T1_INT; 356 mos6522_timer1_update(s, &s->timers[0], 357 qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)); 358 break; 359 case VIA_REG_T2CL: 360 s->timers[1].latch = (s->timers[1].latch & 0xff00) | val; 361 break; 362 case VIA_REG_T2CH: 363 /* To ensure T2 generates an interrupt on zero crossing with the 364 common timer code, write the value directly from the latch to 365 the counter */ 366 s->timers[1].latch = (s->timers[1].latch & 0xff) | (val << 8); 367 s->ifr &= ~T2_INT; 368 set_counter(s, &s->timers[1], s->timers[1].latch); 369 break; 370 case VIA_REG_SR: 371 s->sr = val; 372 break; 373 case VIA_REG_ACR: 374 s->acr = val; 375 mos6522_timer1_update(s, &s->timers[0], 376 qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)); 377 break; 378 case VIA_REG_PCR: 379 s->pcr = val; 380 break; 381 case VIA_REG_IFR: 382 /* reset bits */ 383 s->ifr &= ~val; 384 mos6522_update_irq(s); 385 break; 386 case VIA_REG_IER: 387 if (val & IER_SET) { 388 /* set bits */ 389 s->ier |= val & 0x7f; 390 } else { 391 /* reset bits */ 392 s->ier &= ~val; 393 } 394 mos6522_update_irq(s); 395 /* if IER is modified starts needed timers */ 396 mos6522_timer1_update(s, &s->timers[0], 397 qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)); 398 mos6522_timer2_update(s, &s->timers[1], 399 qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)); 400 break; 401 default: 402 g_assert_not_reached(); 403 } 404} 405 406static const MemoryRegionOps mos6522_ops = { 407 .read = mos6522_read, 408 .write = mos6522_write, 409 .endianness = DEVICE_NATIVE_ENDIAN, 410 .valid = { 411 .min_access_size = 1, 412 .max_access_size = 1, 413 }, 414}; 415 416static const VMStateDescription vmstate_mos6522_timer = { 417 .name = "mos6522_timer", 418 .version_id = 0, 419 .minimum_version_id = 0, 420 .fields = (VMStateField[]) { 421 VMSTATE_UINT16(latch, MOS6522Timer), 422 VMSTATE_UINT16(counter_value, MOS6522Timer), 423 VMSTATE_INT64(load_time, MOS6522Timer), 424 VMSTATE_INT64(next_irq_time, MOS6522Timer), 425 VMSTATE_TIMER_PTR(timer, MOS6522Timer), 426 VMSTATE_END_OF_LIST() 427 } 428}; 429 430const VMStateDescription vmstate_mos6522 = { 431 .name = "mos6522", 432 .version_id = 0, 433 .minimum_version_id = 0, 434 .fields = (VMStateField[]) { 435 VMSTATE_UINT8(a, MOS6522State), 436 VMSTATE_UINT8(b, MOS6522State), 437 VMSTATE_UINT8(dira, MOS6522State), 438 VMSTATE_UINT8(dirb, MOS6522State), 439 VMSTATE_UINT8(sr, MOS6522State), 440 VMSTATE_UINT8(acr, MOS6522State), 441 VMSTATE_UINT8(pcr, MOS6522State), 442 VMSTATE_UINT8(ifr, MOS6522State), 443 VMSTATE_UINT8(ier, MOS6522State), 444 VMSTATE_STRUCT_ARRAY(timers, MOS6522State, 2, 0, 445 vmstate_mos6522_timer, MOS6522Timer), 446 VMSTATE_END_OF_LIST() 447 } 448}; 449 450static void mos6522_reset(DeviceState *dev) 451{ 452 MOS6522State *s = MOS6522(dev); 453 454 s->b = 0; 455 s->a = 0; 456 s->dirb = 0xff; 457 s->dira = 0; 458 s->sr = 0; 459 s->acr = 0; 460 s->pcr = 0; 461 s->ifr = 0; 462 s->ier = 0; 463 /* s->ier = T1_INT | SR_INT; */ 464 465 s->timers[0].frequency = s->frequency; 466 s->timers[0].latch = 0xffff; 467 set_counter(s, &s->timers[0], 0xffff); 468 timer_del(s->timers[0].timer); 469 470 s->timers[1].frequency = s->frequency; 471 s->timers[1].latch = 0xffff; 472 timer_del(s->timers[1].timer); 473} 474 475static void mos6522_init(Object *obj) 476{ 477 SysBusDevice *sbd = SYS_BUS_DEVICE(obj); 478 MOS6522State *s = MOS6522(obj); 479 int i; 480 481 memory_region_init_io(&s->mem, obj, &mos6522_ops, s, "mos6522", 0x10); 482 sysbus_init_mmio(sbd, &s->mem); 483 sysbus_init_irq(sbd, &s->irq); 484 485 for (i = 0; i < ARRAY_SIZE(s->timers); i++) { 486 s->timers[i].index = i; 487 } 488 489 s->timers[0].timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, mos6522_timer1, s); 490 s->timers[1].timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, mos6522_timer2, s); 491} 492 493static void mos6522_finalize(Object *obj) 494{ 495 MOS6522State *s = MOS6522(obj); 496 497 timer_free(s->timers[0].timer); 498 timer_free(s->timers[1].timer); 499} 500 501static Property mos6522_properties[] = { 502 DEFINE_PROP_UINT64("frequency", MOS6522State, frequency, 0), 503 DEFINE_PROP_END_OF_LIST() 504}; 505 506static void mos6522_class_init(ObjectClass *oc, void *data) 507{ 508 DeviceClass *dc = DEVICE_CLASS(oc); 509 MOS6522DeviceClass *mdc = MOS6522_CLASS(oc); 510 511 dc->reset = mos6522_reset; 512 dc->vmsd = &vmstate_mos6522; 513 device_class_set_props(dc, mos6522_properties); 514 mdc->parent_reset = dc->reset; 515 mdc->set_sr_int = mos6522_set_sr_int; 516 mdc->portB_write = mos6522_portB_write; 517 mdc->portA_write = mos6522_portA_write; 518 mdc->update_irq = mos6522_update_irq; 519 mdc->get_timer1_counter_value = mos6522_get_counter_value; 520 mdc->get_timer2_counter_value = mos6522_get_counter_value; 521 mdc->get_timer1_load_time = mos6522_get_load_time; 522 mdc->get_timer2_load_time = mos6522_get_load_time; 523} 524 525static const TypeInfo mos6522_type_info = { 526 .name = TYPE_MOS6522, 527 .parent = TYPE_SYS_BUS_DEVICE, 528 .instance_size = sizeof(MOS6522State), 529 .instance_init = mos6522_init, 530 .instance_finalize = mos6522_finalize, 531 .abstract = true, 532 .class_size = sizeof(MOS6522DeviceClass), 533 .class_init = mos6522_class_init, 534}; 535 536static void mos6522_register_types(void) 537{ 538 type_register_static(&mos6522_type_info); 539} 540 541type_init(mos6522_register_types)