hw/dma/i8257.c

   1 /*
   2  * QEMU DMA emulation
   3  *
   4  * Copyright (c) 2003-2004 Vassili Karpov (malc)
   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 "hw/hw.h"
  25 #include "hw/isa/isa.h"
  26 #include "qemu/main-loop.h"
  27 #include "trace.h"
  28
  29 /* #define DEBUG_DMA */
  30
  31 #define dolog(...) fprintf (stderr, "dma: " __VA_ARGS__)
  32 #ifdef DEBUG_DMA
  33 #define linfo(...) fprintf (stderr, "dma: " __VA_ARGS__)
  34 #define ldebug(...) fprintf (stderr, "dma: " __VA_ARGS__)
  35 #else
  36 #define linfo(...)
  37 #define ldebug(...)
  38 #endif
  39
  40 struct dma_regs {
  41     int now[2];
  42     uint16_t base[2];
  43     uint8_t mode;
  44     uint8_t page;
  45     uint8_t pageh;
  46     uint8_t dack;
  47     uint8_t eop;
  48     DMA_transfer_handler transfer_handler;
  49     void *opaque;
  50 };
  51
  52 #define ADDR 0
  53 #define COUNT 1
  54
  55 static struct dma_cont {
  56     uint8_t status;
  57     uint8_t command;
  58     uint8_t mask;
  59     uint8_t flip_flop;
  60     int dshift;
  61     struct dma_regs regs[4];
  62     MemoryRegion channel_io;
  63     MemoryRegion cont_io;
  64 } dma_controllers[2];
  65
  66 enum {
  67     CMD_MEMORY_TO_MEMORY = 0x01,
  68     CMD_FIXED_ADDRESS    = 0x02,
  69     CMD_BLOCK_CONTROLLER = 0x04,
  70     CMD_COMPRESSED_TIME  = 0x08,
  71     CMD_CYCLIC_PRIORITY  = 0x10,
  72     CMD_EXTENDED_WRITE   = 0x20,
  73     CMD_LOW_DREQ         = 0x40,
  74     CMD_LOW_DACK         = 0x80,
  75     CMD_NOT_SUPPORTED    = CMD_MEMORY_TO_MEMORY | CMD_FIXED_ADDRESS
  76     | CMD_COMPRESSED_TIME | CMD_CYCLIC_PRIORITY | CMD_EXTENDED_WRITE
  77     | CMD_LOW_DREQ | CMD_LOW_DACK
  78
  79 };
  80
  81 static void DMA_run (void);
  82
  83 static int channels[8] = {-1, 2, 3, 1, -1, -1, -1, 0};
  84
  85 static void write_page (void *opaque, uint32_t nport, uint32_t data)
  86 {
  87     struct dma_cont *d = opaque;
  88     int ichan;
  89
  90     ichan = channels[nport & 7];
  91     if (-1 == ichan) {
  92         dolog ("invalid channel %#x %#x\n", nport, data);
  93         return;
  94     }
  95     d->regs[ichan].page = data;
  96 }
  97
  98 static void write_pageh (void *opaque, uint32_t nport, uint32_t data)
  99 {
 100     struct dma_cont *d = opaque;
 101     int ichan;
 102
 103     ichan = channels[nport & 7];
 104     if (-1 == ichan) {
 105         dolog ("invalid channel %#x %#x\n", nport, data);
 106         return;
 107     }
 108     d->regs[ichan].pageh = data;
 109 }
 110
 111 static uint32_t read_page (void *opaque, uint32_t nport)
 112 {
 113     struct dma_cont *d = opaque;
 114     int ichan;
 115
 116     ichan = channels[nport & 7];
 117     if (-1 == ichan) {
 118         dolog ("invalid channel read %#x\n", nport);
 119         return 0;
 120     }
 121     return d->regs[ichan].page;
 122 }
 123
 124 static uint32_t read_pageh (void *opaque, uint32_t nport)
 125 {
 126     struct dma_cont *d = opaque;
 127     int ichan;
 128
 129     ichan = channels[nport & 7];
 130     if (-1 == ichan) {
 131         dolog ("invalid channel read %#x\n", nport);
 132         return 0;
 133     }
 134     return d->regs[ichan].pageh;
 135 }
 136
 137 static inline void init_chan (struct dma_cont *d, int ichan)
 138 {
 139     struct dma_regs *r;
 140
 141     r = d->regs + ichan;
 142     r->now[ADDR] = r->base[ADDR] << d->dshift;
 143     r->now[COUNT] = 0;
 144 }
 145
 146 static inline int getff (struct dma_cont *d)
 147 {
 148     int ff;
 149
 150     ff = d->flip_flop;
 151     d->flip_flop = !ff;
 152     return ff;
 153 }
 154
 155 static uint64_t read_chan(void *opaque, hwaddr nport, unsigned size)
 156 {
 157     struct dma_cont *d = opaque;
 158     int ichan, nreg, iport, ff, val, dir;
 159     struct dma_regs *r;
 160
 161     iport = (nport >> d->dshift) & 0x0f;
 162     ichan = iport >> 1;
 163     nreg = iport & 1;
 164     r = d->regs + ichan;
 165
 166     dir = ((r->mode >> 5) & 1) ? -1 : 1;
 167     ff = getff (d);
 168     if (nreg)
 169         val = (r->base[COUNT] << d->dshift) - r->now[COUNT];
 170     else
 171         val = r->now[ADDR] + r->now[COUNT] * dir;
 172
 173     ldebug ("read_chan %#x -> %d\n", iport, val);
 174     return (val >> (d->dshift + (ff << 3))) & 0xff;
 175 }
 176
 177 static void write_chan(void *opaque, hwaddr nport, uint64_t data,
 178                        unsigned size)
 179 {
 180     struct dma_cont *d = opaque;
 181     int iport, ichan, nreg;
 182     struct dma_regs *r;
 183
 184     iport = (nport >> d->dshift) & 0x0f;
 185     ichan = iport >> 1;
 186     nreg = iport & 1;
 187     r = d->regs + ichan;
 188     if (getff (d)) {
 189         r->base[nreg] = (r->base[nreg] & 0xff) | ((data << 8) & 0xff00);
 190         init_chan (d, ichan);
 191     } else {
 192         r->base[nreg] = (r->base[nreg] & 0xff00) | (data & 0xff);
 193     }
 194 }
 195
 196 static void write_cont(void *opaque, hwaddr nport, uint64_t data,
 197                        unsigned size)
 198 {
 199     struct dma_cont *d = opaque;
 200     int iport, ichan = 0;
 201
 202     iport = (nport >> d->dshift) & 0x0f;
 203     switch (iport) {
 204     case 0x00:                  /* command */
 205         if ((data != 0) && (data & CMD_NOT_SUPPORTED)) {
 206             dolog("command %"PRIx64" not supported\n", data);
 207             return;
 208         }
 209         d->command = data;
 210         break;
 211
 212     case 0x01:
 213         ichan = data & 3;
 214         if (data & 4) {
 215             d->status |= 1 << (ichan + 4);
 216         }
 217         else {
 218             d->status &= ~(1 << (ichan + 4));
 219         }
 220         d->status &= ~(1 << ichan);
 221         DMA_run();
 222         break;
 223
 224     case 0x02:                  /* single mask */
 225         if (data & 4)
 226             d->mask |= 1 << (data & 3);
 227         else
 228             d->mask &= ~(1 << (data & 3));
 229         DMA_run();
 230         break;
 231
 232     case 0x03:                  /* mode */
 233         {
 234             ichan = data & 3;
 235 #ifdef DEBUG_DMA
 236             {
 237                 int op, ai, dir, opmode;
 238                 op = (data >> 2) & 3;
 239                 ai = (data >> 4) & 1;
 240                 dir = (data >> 5) & 1;
 241                 opmode = (data >> 6) & 3;
 242
 243                 linfo ("ichan %d, op %d, ai %d, dir %d, opmode %d\n",
 244                        ichan, op, ai, dir, opmode);
 245             }
 246 #endif
 247             d->regs[ichan].mode = data;
 248             break;
 249         }
 250
 251     case 0x04:                  /* clear flip flop */
 252         d->flip_flop = 0;
 253         break;
 254
 255     case 0x05:                  /* reset */
 256         d->flip_flop = 0;
 257         d->mask = ~0;
 258         d->status = 0;
 259         d->command = 0;
 260         break;
 261
 262     case 0x06:                  /* clear mask for all channels */
 263         d->mask = 0;
 264         DMA_run();
 265         break;
 266
 267     case 0x07:                  /* write mask for all channels */
 268         d->mask = data;
 269         DMA_run();
 270         break;
 271
 272     default:
 273         dolog ("unknown iport %#x\n", iport);
 274         break;
 275     }
 276
 277 #ifdef DEBUG_DMA
 278     if (0xc != iport) {
 279         linfo ("write_cont: nport %#06x, ichan % 2d, val %#06x\n",
 280                nport, ichan, data);
 281     }
 282 #endif
 283 }
 284
 285 static uint64_t read_cont(void *opaque, hwaddr nport, unsigned size)
 286 {
 287     struct dma_cont *d = opaque;
 288     int iport, val;
 289
 290     iport = (nport >> d->dshift) & 0x0f;
 291     switch (iport) {
 292     case 0x00:                  /* status */
 293         val = d->status;
 294         d->status &= 0xf0;
 295         break;
 296     case 0x01:                  /* mask */
 297         val = d->mask;
 298         break;
 299     default:
 300         val = 0;
 301         break;
 302     }
 303
 304     ldebug ("read_cont: nport %#06x, iport %#04x val %#x\n", nport, iport, val);
 305     return val;
 306 }
 307
 308 int DMA_get_channel_mode (int nchan)
 309 {
 310     return dma_controllers[nchan > 3].regs[nchan & 3].mode;
 311 }
 312
 313 void DMA_hold_DREQ (int nchan)
 314 {
 315     int ncont, ichan;
 316
 317     ncont = nchan > 3;
 318     ichan = nchan & 3;
 319     linfo ("held cont=%d chan=%d\n", ncont, ichan);
 320     dma_controllers[ncont].status |= 1 << (ichan + 4);
 321     DMA_run();
 322 }
 323
 324 void DMA_release_DREQ (int nchan)
 325 {
 326     int ncont, ichan;
 327
 328     ncont = nchan > 3;
 329     ichan = nchan & 3;
 330     linfo ("released cont=%d chan=%d\n", ncont, ichan);
 331     dma_controllers[ncont].status &= ~(1 << (ichan + 4));
 332     DMA_run();
 333 }
 334
 335 static void channel_run (int ncont, int ichan)
 336 {
 337     int n;
 338     struct dma_regs *r = &dma_controllers[ncont].regs[ichan];
 339 #ifdef DEBUG_DMA
 340     int dir, opmode;
 341
 342     dir = (r->mode >> 5) & 1;
 343     opmode = (r->mode >> 6) & 3;
 344
 345     if (dir) {
 346         dolog ("DMA in address decrement mode\n");
 347     }
 348     if (opmode != 1) {
 349         dolog ("DMA not in single mode select %#x\n", opmode);
 350     }
 351 #endif
 352
 353     n = r->transfer_handler (r->opaque, ichan + (ncont << 2),
 354                              r->now[COUNT], (r->base[COUNT] + 1) << ncont);
 355     r->now[COUNT] = n;
 356     ldebug ("dma_pos %d size %d\n", n, (r->base[COUNT] + 1) << ncont);
 357 }
 358
 359 static QEMUBH *dma_bh;
 360 static bool dma_bh_scheduled;
 361
 362 static void DMA_run (void)
 363 {
 364     struct dma_cont *d;
 365     int icont, ichan;
 366     int rearm = 0;
 367     static int running = 0;
 368
 369     if (running) {
 370         rearm = 1;
 371         goto out;
 372     } else {
 373         running = 1;
 374     }
 375
 376     d = dma_controllers;
 377
 378     for (icont = 0; icont < 2; icont++, d++) {
 379         for (ichan = 0; ichan < 4; ichan++) {
 380             int mask;
 381
 382             mask = 1 << ichan;
 383
 384             if ((0 == (d->mask & mask)) && (0 != (d->status & (mask << 4)))) {
 385                 channel_run (icont, ichan);
 386                 rearm = 1;
 387             }
 388         }
 389     }
 390
 391     running = 0;
 392 out:
 393     if (rearm) {
 394         qemu_bh_schedule_idle(dma_bh);
 395         dma_bh_scheduled = true;
 396     }
 397 }
 398
 399 static void DMA_run_bh(void *unused)
 400 {
 401     dma_bh_scheduled = false;
 402     DMA_run();
 403 }
 404
 405 void DMA_register_channel (int nchan,
 406                            DMA_transfer_handler transfer_handler,
 407                            void *opaque)
 408 {
 409     struct dma_regs *r;
 410     int ichan, ncont;
 411
 412     ncont = nchan > 3;
 413     ichan = nchan & 3;
 414
 415     r = dma_controllers[ncont].regs + ichan;
 416     r->transfer_handler = transfer_handler;
 417     r->opaque = opaque;
 418 }
 419
 420 int DMA_read_memory (int nchan, void *buf, int pos, int len)
 421 {
 422     struct dma_regs *r = &dma_controllers[nchan > 3].regs[nchan & 3];
 423     hwaddr addr = ((r->pageh & 0x7f) << 24) | (r->page << 16) | r->now[ADDR];
 424
 425     if (r->mode & 0x20) {
 426         int i;
 427         uint8_t *p = buf;
 428
 429         cpu_physical_memory_read (addr - pos - len, buf, len);
 430         /* What about 16bit transfers? */
 431         for (i = 0; i < len >> 1; i++) {
 432             uint8_t b = p[len - i - 1];
 433             p[i] = b;
 434         }
 435     }
 436     else
 437         cpu_physical_memory_read (addr + pos, buf, len);
 438
 439     return len;
 440 }
 441
 442 int DMA_write_memory (int nchan, void *buf, int pos, int len)
 443 {
 444     struct dma_regs *r = &dma_controllers[nchan > 3].regs[nchan & 3];
 445     hwaddr addr = ((r->pageh & 0x7f) << 24) | (r->page << 16) | r->now[ADDR];
 446
 447     if (r->mode & 0x20) {
 448         int i;
 449         uint8_t *p = buf;
 450
 451         cpu_physical_memory_write (addr - pos - len, buf, len);
 452         /* What about 16bit transfers? */
 453         for (i = 0; i < len; i++) {
 454             uint8_t b = p[len - i - 1];
 455             p[i] = b;
 456         }
 457     }
 458     else
 459         cpu_physical_memory_write (addr + pos, buf, len);
 460
 461     return len;
 462 }
 463
 464 /* request the emulator to transfer a new DMA memory block ASAP (even
 465  * if the idle bottom half would not have exited the iothread yet).
 466  */
 467 void DMA_schedule(void)
 468 {
 469     if (dma_bh_scheduled) {
 470         qemu_notify_event();
 471     }
 472 }
 473
 474 static void dma_reset(void *opaque)
 475 {
 476     struct dma_cont *d = opaque;
 477     write_cont(d, (0x05 << d->dshift), 0, 1);
 478 }
 479
 480 static int dma_phony_handler (void *opaque, int nchan, int dma_pos, int dma_len)
 481 {
 482     trace_i8257_unregistered_dma(nchan, dma_pos, dma_len);
 483     return dma_pos;
 484 }
 485
 486
 487 static const MemoryRegionOps channel_io_ops = {
 488     .read = read_chan,
 489     .write = write_chan,
 490     .endianness = DEVICE_NATIVE_ENDIAN,
 491     .impl = {
 492         .min_access_size = 1,
 493         .max_access_size = 1,
 494     },
 495 };
 496
 497 /* IOport from page_base */
 498 static const MemoryRegionPortio page_portio_list[] = {
 499     { 0x01, 3, 1, .write = write_page, .read = read_page, },
 500     { 0x07, 1, 1, .write = write_page, .read = read_page, },
 501     PORTIO_END_OF_LIST(),
 502 };
 503
 504 /* IOport from pageh_base */
 505 static const MemoryRegionPortio pageh_portio_list[] = {
 506     { 0x01, 3, 1, .write = write_pageh, .read = read_pageh, },
 507     { 0x07, 3, 1, .write = write_pageh, .read = read_pageh, },
 508     PORTIO_END_OF_LIST(),
 509 };
 510
 511 static const MemoryRegionOps cont_io_ops = {
 512     .read = read_cont,
 513     .write = write_cont,
 514     .endianness = DEVICE_NATIVE_ENDIAN,
 515     .impl = {
 516         .min_access_size = 1,
 517         .max_access_size = 1,
 518     },
 519 };
 520
 521 /* dshift = 0: 8 bit DMA, 1 = 16 bit DMA */
 522 static void dma_init2(struct dma_cont *d, int base, int dshift,
 523                       int page_base, int pageh_base)
 524 {
 525     int i;
 526
 527     d->dshift = dshift;
 528
 529     memory_region_init_io(&d->channel_io, NULL, &channel_io_ops, d,
 530                           "dma-chan", 8 << d->dshift);
 531     memory_region_add_subregion(isa_address_space_io(NULL),
 532                                 base, &d->channel_io);
 533
 534     isa_register_portio_list(NULL, page_base, page_portio_list, d,
 535                              "dma-page");
 536     if (pageh_base >= 0) {
 537         isa_register_portio_list(NULL, pageh_base, pageh_portio_list, d,
 538                                  "dma-pageh");
 539     }
 540
 541     memory_region_init_io(&d->cont_io, NULL, &cont_io_ops, d, "dma-cont",
 542                           8 << d->dshift);
 543     memory_region_add_subregion(isa_address_space_io(NULL),
 544                                 base + (8 << d->dshift), &d->cont_io);
 545
 546     qemu_register_reset(dma_reset, d);
 547     dma_reset(d);
 548     for (i = 0; i < ARRAY_SIZE (d->regs); ++i) {
 549         d->regs[i].transfer_handler = dma_phony_handler;
 550     }
 551 }
 552
 553 static const VMStateDescription vmstate_dma_regs = {
 554     .name = "dma_regs",
 555     .version_id = 1,
 556     .minimum_version_id = 1,
 557     .fields = (VMStateField[]) {
 558         VMSTATE_INT32_ARRAY(now, struct dma_regs, 2),
 559         VMSTATE_UINT16_ARRAY(base, struct dma_regs, 2),
 560         VMSTATE_UINT8(mode, struct dma_regs),
 561         VMSTATE_UINT8(page, struct dma_regs),
 562         VMSTATE_UINT8(pageh, struct dma_regs),
 563         VMSTATE_UINT8(dack, struct dma_regs),
 564         VMSTATE_UINT8(eop, struct dma_regs),
 565         VMSTATE_END_OF_LIST()
 566     }
 567 };
 568
 569 static int dma_post_load(void *opaque, int version_id)
 570 {
 571     DMA_run();
 572
 573     return 0;
 574 }
 575
 576 static const VMStateDescription vmstate_dma = {
 577     .name = "dma",
 578     .version_id = 1,
 579     .minimum_version_id = 1,
 580     .post_load = dma_post_load,
 581     .fields = (VMStateField[]) {
 582         VMSTATE_UINT8(command, struct dma_cont),
 583         VMSTATE_UINT8(mask, struct dma_cont),
 584         VMSTATE_UINT8(flip_flop, struct dma_cont),
 585         VMSTATE_INT32(dshift, struct dma_cont),
 586         VMSTATE_STRUCT_ARRAY(regs, struct dma_cont, 4, 1, vmstate_dma_regs, struct dma_regs),
 587         VMSTATE_END_OF_LIST()
 588     }
 589 };
 590
 591 void DMA_init(int high_page_enable)
 592 {
 593     dma_init2(&dma_controllers[0], 0x00, 0, 0x80, high_page_enable ? 0x480 : -1);
 594     dma_init2(&dma_controllers[1], 0xc0, 1, 0x88, high_page_enable ? 0x488 : -1);
 595     vmstate_register (NULL, 0, &vmstate_dma, &dma_controllers[0]);
 596     vmstate_register (NULL, 1, &vmstate_dma, &dma_controllers[1]);
 597
 598     dma_bh = qemu_bh_new(DMA_run_bh, NULL);
 599 }