1 /*- 2 * Copyright (c) 2015 M. Warner Losh <imp@FreeBSD.org> 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice unmodified, this list of conditions, and the following 9 * disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #include <sys/param.h> 27 #include <sys/systm.h> 28 #include <sys/kernel.h> 29 30 #include <sys/bus.h> 31 #include <sys/errno.h> 32 #include <sys/libkern.h> 33 #include <sys/lock.h> 34 #include <sys/malloc.h> 35 #include <sys/module.h> 36 #include <sys/mutex.h> 37 #include <sys/sbuf.h> 38 #include <sys/sysctl.h> 39 40 #include <dev/ow/ow.h> 41 #include <dev/ow/owll.h> 42 #include <dev/ow/own.h> 43 44 /* 45 * lldev - link level device 46 * ndev - network / transport device (this module) 47 * pdev - presentation device (children of this module) 48 */ 49 50 typedef int ow_enum_fn(device_t, device_t); 51 typedef int ow_found_fn(device_t, romid_t); 52 53 struct ow_softc 54 { 55 device_t dev; /* Newbus driver back pointer */ 56 struct mtx mtx; /* bus mutex */ 57 device_t owner; /* bus owner, if != NULL */ 58 }; 59 60 struct ow_devinfo 61 { 62 romid_t romid; 63 }; 64 65 static int ow_acquire_bus(device_t ndev, device_t pdev, int how); 66 static void ow_release_bus(device_t ndev, device_t pdev); 67 68 #define OW_LOCK(_sc) mtx_lock(&(_sc)->mtx) 69 #define OW_UNLOCK(_sc) mtx_unlock(&(_sc)->mtx) 70 #define OW_LOCK_DESTROY(_sc) mtx_destroy(&_sc->mtx) 71 #define OW_ASSERT_LOCKED(_sc) mtx_assert(&_sc->mtx, MA_OWNED) 72 #define OW_ASSERT_UNLOCKED(_sc) mtx_assert(&_sc->mtx, MA_NOTOWNED) 73 74 static MALLOC_DEFINE(M_OW, "ow", "House keeping data for 1wire bus"); 75 76 static const struct ow_timing timing_regular_min = { 77 .t_slot = 60, 78 .t_low0 = 60, 79 .t_low1 = 1, 80 .t_release = 0, 81 .t_rec = 1, 82 .t_rdv = 15, /* fixed */ 83 .t_rstl = 480, 84 .t_rsth = 480, 85 .t_pdl = 60, 86 .t_pdh = 15, 87 .t_lowr = 1, 88 }; 89 90 static const struct ow_timing timing_regular_max = { 91 .t_slot = 120, 92 .t_low0 = 120, 93 .t_low1 = 15, 94 .t_release = 45, 95 .t_rec = 960, /* infinity */ 96 .t_rdv = 15, /* fixed */ 97 .t_rstl = 960, /* infinity */ 98 .t_rsth = 960, /* infinity */ 99 .t_pdl = 240, /* 60us to 240us */ 100 .t_pdh = 60, /* 15us to 60us */ 101 .t_lowr = 15, /* 1us */ 102 }; 103 104 static struct ow_timing timing_regular = { 105 .t_slot = 60, /* 60 <= t < 120 */ 106 .t_low0 = 60, /* 60 <= t < t_slot < 120 */ 107 .t_low1 = 1, /* 1 <= t < 15 */ 108 .t_release = 45, /* 0 <= t < 45 */ 109 .t_rec = 15, /* 1 <= t < inf */ 110 .t_rdv = 15, /* t == 15 */ 111 .t_rstl = 480, /* 480 <= t < inf */ 112 .t_rsth = 480, /* 480 <= t < inf */ 113 .t_pdl = 60, /* 60 <= t < 240 */ 114 .t_pdh = 60, /* 15 <= t < 60 */ 115 .t_lowr = 1, /* 1 <= t < 15 */ 116 }; 117 118 /* NB: Untested */ 119 static const struct ow_timing timing_overdrive_min = { 120 .t_slot = 6, 121 .t_low0 = 6, 122 .t_low1 = 1, 123 .t_release = 0, 124 .t_rec = 1, 125 .t_rdv = 2, /* fixed */ 126 .t_rstl = 48, 127 .t_rsth = 48, 128 .t_pdl = 8, 129 .t_pdh = 2, 130 .t_lowr = 1, 131 }; 132 133 static const struct ow_timing timing_overdrive_max = { 134 .t_slot = 16, 135 .t_low0 = 16, 136 .t_low1 = 2, 137 .t_release = 4, 138 .t_rec = 960, /* infinity */ 139 .t_rdv = 2, /* fixed */ 140 .t_rstl = 80, 141 .t_rsth = 960, /* infinity */ 142 .t_pdl = 24, 143 .t_pdh = 6, 144 .t_lowr = 2, 145 }; 146 147 static struct ow_timing timing_overdrive = { 148 .t_slot = 11, /* 6 <= t < 16 */ 149 .t_low0 = 6, /* 6 <= t < t_slot < 16 */ 150 .t_low1 = 1, /* 1 <= t < 2 */ 151 .t_release = 4, /* 0 <= t < 4 */ 152 .t_rec = 1, /* 1 <= t < inf */ 153 .t_rdv = 2, /* t == 2 */ 154 .t_rstl = 48, /* 48 <= t < 80 */ 155 .t_rsth = 48, /* 48 <= t < inf */ 156 .t_pdl = 8, /* 8 <= t < 24 */ 157 .t_pdh = 2, /* 2 <= t < 6 */ 158 .t_lowr = 1, /* 1 <= t < 2 */ 159 }; 160 161 SYSCTL_NODE(_hw, OID_AUTO, ow, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 162 "1-Wire protocol"); 163 SYSCTL_NODE(_hw_ow, OID_AUTO, regular, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 164 "Regular mode timings"); 165 SYSCTL_NODE(_hw_ow, OID_AUTO, overdrive, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 166 "Overdrive mode timings"); 167 168 #define _OW_TIMING_SYSCTL(mode, param) \ 169 static int \ 170 sysctl_ow_timing_ ## mode ## _ ## param(SYSCTL_HANDLER_ARGS) \ 171 { \ 172 int val = timing_ ## mode.param; \ 173 int err; \ 174 err = sysctl_handle_int(oidp, &val, 0, req); \ 175 if (err != 0 || req->newptr == NULL) \ 176 return (err); \ 177 if (val < timing_ ## mode ## _min.param) \ 178 return (EINVAL); \ 179 else if (val >= timing_ ## mode ## _max.param) \ 180 return (EINVAL); \ 181 timing_ ## mode.param = val; \ 182 return (0); \ 183 } \ 184 SYSCTL_PROC(_hw_ow_ ## mode, OID_AUTO, param, \ 185 CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_NEEDGIANT, 0, sizeof(int), \ 186 sysctl_ow_timing_ ## mode ## _ ## param, "I", \ 187 "1-Wire timing parameter in microseconds (-1 resets to default)") 188 189 #define OW_TIMING_SYSCTL(param) \ 190 _OW_TIMING_SYSCTL(regular, param); \ 191 _OW_TIMING_SYSCTL(overdrive, param) 192 193 OW_TIMING_SYSCTL(t_slot); 194 OW_TIMING_SYSCTL(t_low0); 195 OW_TIMING_SYSCTL(t_low1); 196 OW_TIMING_SYSCTL(t_release); 197 OW_TIMING_SYSCTL(t_rec); 198 OW_TIMING_SYSCTL(t_rdv); 199 OW_TIMING_SYSCTL(t_rstl); 200 OW_TIMING_SYSCTL(t_rsth); 201 OW_TIMING_SYSCTL(t_pdl); 202 OW_TIMING_SYSCTL(t_pdh); 203 OW_TIMING_SYSCTL(t_lowr); 204 205 #undef _OW_TIMING_SYSCTL 206 #undef OW_TIMING_SYSCTL 207 208 static void 209 ow_send_byte(device_t lldev, struct ow_timing *t, uint8_t byte) 210 { 211 int i; 212 213 for (i = 0; i < 8; i++) 214 if (byte & (1 << i)) 215 OWLL_WRITE_ONE(lldev, t); 216 else 217 OWLL_WRITE_ZERO(lldev, t); 218 } 219 220 static void 221 ow_read_byte(device_t lldev, struct ow_timing *t, uint8_t *bytep) 222 { 223 int i; 224 uint8_t byte = 0; 225 int bit; 226 227 for (i = 0; i < 8; i++) { 228 OWLL_READ_DATA(lldev, t, &bit); 229 byte |= bit << i; 230 } 231 *bytep = byte; 232 } 233 234 static int 235 ow_send_command(device_t ndev, device_t pdev, struct ow_cmd *cmd) 236 { 237 int present, i, bit, tries; 238 device_t lldev; 239 struct ow_timing *t; 240 241 lldev = device_get_parent(ndev); 242 243 /* 244 * Retry the reset a couple of times before giving up. 245 */ 246 tries = 4; 247 do { 248 OWLL_RESET_AND_PRESENCE(lldev, &timing_regular, &present); 249 if (present == 1) 250 device_printf(ndev, "Reset said no device on bus?.\n"); 251 } while (present == 1 && tries-- > 0); 252 if (present == 1) { 253 device_printf(ndev, "Reset said the device wasn't there.\n"); 254 return ENOENT; /* No devices acked the RESET */ 255 } 256 if (present == -1) { 257 device_printf(ndev, "Reset discovered bus wired wrong.\n"); 258 return ENOENT; 259 } 260 261 for (i = 0; i < cmd->rom_len; i++) 262 ow_send_byte(lldev, &timing_regular, cmd->rom_cmd[i]); 263 for (i = 0; i < cmd->rom_read_len; i++) 264 ow_read_byte(lldev, &timing_regular, cmd->rom_read + i); 265 if (cmd->xpt_len) { 266 /* 267 * Per AN937, the reset pulse and ROM level are always 268 * done with the regular timings. Certain ROM commands 269 * put the device into overdrive mode for the remainder 270 * of the data transfer, which is why we have to pass the 271 * timings here. Commands that need to be handled like this 272 * are expected to be flagged by the client. 273 */ 274 t = (cmd->flags & OW_FLAG_OVERDRIVE) ? 275 &timing_overdrive : &timing_regular; 276 for (i = 0; i < cmd->xpt_len; i++) 277 ow_send_byte(lldev, t, cmd->xpt_cmd[i]); 278 if (cmd->flags & OW_FLAG_READ_BIT) { 279 memset(cmd->xpt_read, 0, (cmd->xpt_read_len + 7) / 8); 280 for (i = 0; i < cmd->xpt_read_len; i++) { 281 OWLL_READ_DATA(lldev, t, &bit); 282 cmd->xpt_read[i / 8] |= bit << (i % 8); 283 } 284 } else { 285 for (i = 0; i < cmd->xpt_read_len; i++) 286 ow_read_byte(lldev, t, cmd->xpt_read + i); 287 } 288 } 289 return 0; 290 } 291 292 static int 293 ow_search_rom(device_t lldev, device_t dev) 294 { 295 struct ow_cmd cmd; 296 297 memset(&cmd, 0, sizeof(cmd)); 298 cmd.rom_cmd[0] = SEARCH_ROM; 299 cmd.rom_len = 1; 300 return ow_send_command(lldev, dev, &cmd); 301 } 302 303 #if 0 304 static int 305 ow_alarm_search(device_t lldev, device_t dev) 306 { 307 struct ow_cmd cmd; 308 309 memset(&cmd, 0, sizeof(cmd)); 310 cmd.rom_cmd[0] = ALARM_SEARCH; 311 cmd.rom_len = 1; 312 return ow_send_command(lldev, dev, &cmd); 313 } 314 #endif 315 316 static int 317 ow_add_child(device_t dev, romid_t romid) 318 { 319 struct ow_devinfo *di; 320 device_t child; 321 322 di = malloc(sizeof(*di), M_OW, M_WAITOK); 323 di->romid = romid; 324 child = device_add_child(dev, NULL, DEVICE_UNIT_ANY); 325 if (child == NULL) { 326 free(di, M_OW); 327 return ENOMEM; 328 } 329 device_set_ivars(child, di); 330 return (0); 331 } 332 333 static device_t 334 ow_child_by_romid(device_t dev, romid_t romid) 335 { 336 device_t *children, retval, child; 337 int nkid, i; 338 struct ow_devinfo *di; 339 340 if (device_get_children(dev, &children, &nkid) != 0) 341 return (NULL); 342 retval = NULL; 343 for (i = 0; i < nkid; i++) { 344 child = children[i]; 345 di = device_get_ivars(child); 346 if (di->romid == romid) { 347 retval = child; 348 break; 349 } 350 } 351 free(children, M_TEMP); 352 353 return (retval); 354 } 355 356 /* 357 * CRC generator table -- taken from AN937 DOW CRC LOOKUP FUNCTION Table 2 358 */ 359 const uint8_t ow_crc_table[] = { 360 0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65, 361 157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220, 362 35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98, 363 190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255, 364 70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7, 365 219, 133,103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154, 366 101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36, 367 248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185, 368 140,210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113,147, 205, 369 17, 79, 173, 243, 112, 46, 204, 146, 211,141, 111, 49, 178, 236, 14, 80, 370 175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82,176, 238, 371 50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115, 372 202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139, 373 87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22, 374 233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168, 375 116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53 376 }; 377 378 /* 379 * Converted from DO_CRC page 131 ANN937 380 */ 381 static uint8_t 382 ow_crc(device_t ndev, device_t pdev, uint8_t *buffer, size_t len) 383 { 384 uint8_t crc = 0; 385 int i; 386 387 for (i = 0; i < len; i++) 388 crc = ow_crc_table[crc ^ buffer[i]]; 389 return crc; 390 } 391 392 static int 393 ow_check_crc(romid_t romid) 394 { 395 return ow_crc(NULL, NULL, (uint8_t *)&romid, sizeof(romid)) == 0; 396 } 397 398 static int 399 ow_device_found(device_t dev, romid_t romid) 400 { 401 402 /* XXX Move this up into enumerate? */ 403 /* 404 * All valid ROM IDs have a valid CRC. Check that first. 405 */ 406 if (!ow_check_crc(romid)) { 407 device_printf(dev, "Device romid %8D failed CRC.\n", 408 &romid, ":"); 409 return EINVAL; 410 } 411 412 /* 413 * If we've seen this child before, don't add a new one for it. 414 */ 415 if (ow_child_by_romid(dev, romid) != NULL) 416 return 0; 417 418 return ow_add_child(dev, romid); 419 } 420 421 static int 422 ow_enumerate(device_t dev, ow_enum_fn *enumfp, ow_found_fn *foundfp) 423 { 424 device_t lldev = device_get_parent(dev); 425 int first, second, i, dir, prior, last, err, retries; 426 uint64_t probed, last_mask; 427 int sanity = 10; 428 429 prior = -1; 430 last_mask = 0; 431 retries = 0; 432 last = -2; 433 err = ow_acquire_bus(dev, dev, OWN_DONTWAIT); 434 if (err != 0) 435 return err; 436 while (last != -1) { 437 if (sanity-- < 0) { 438 printf("Reached the sanity limit\n"); 439 return EIO; 440 } 441 again: 442 probed = 0; 443 last = -1; 444 445 /* 446 * See AN397 section 5.II.C.3 for the algorithm (though a bit 447 * poorly stated). The search command forces each device to 448 * send ROM ID bits one at a time (first the bit, then the 449 * complement) the master (us) sends back a bit. If the 450 * device's bit doesn't match what we send back, that device 451 * stops sending bits back. So each time through we remember 452 * where we made the last decision (always 0). If there's a 453 * conflict there this time (and there will be in the absence 454 * of a hardware failure) we go with 1. This way, we prune the 455 * devices on the bus and wind up with a unique ROM. We know 456 * we're done when we detect no new conflicts. The same 457 * algorithm is used for devices in alarm state as well. 458 * 459 * In addition, experience has shown that sometimes devices 460 * stop responding in the middle of enumeration, so try this 461 * step again a few times when that happens. It is unclear if 462 * this is due to a nosiy electrical environment or some odd 463 * timing issue. 464 */ 465 466 /* 467 * The enumeration command should be successfully sent, if not, 468 * we have big issues on the bus so punt. Lower layers report 469 * any unusual errors, so we don't need to here. 470 */ 471 err = enumfp(dev, dev); 472 if (err != 0) 473 return (err); 474 475 for (i = 0; i < 64; i++) { 476 OWLL_READ_DATA(lldev, &timing_regular, &first); 477 OWLL_READ_DATA(lldev, &timing_regular, &second); 478 switch (first | second << 1) { 479 case 0: /* Conflict */ 480 if (i < prior) 481 dir = (last_mask >> i) & 1; 482 else 483 dir = i == prior; 484 485 if (dir == 0) 486 last = i; 487 break; 488 case 1: /* 1 then 0 -> 1 for all */ 489 dir = 1; 490 break; 491 case 2: /* 0 then 1 -> 0 for all */ 492 dir = 0; 493 break; 494 case 3: 495 /* 496 * No device responded. This is unexpected, but 497 * experience has shown that on some platforms 498 * we miss a timing window, or otherwise have 499 * an issue. Start this step over. Since we've 500 * not updated prior yet, we can just jump to 501 * the top of the loop for a re-do of this step. 502 */ 503 printf("oops, starting over\n"); 504 if (++retries > 5) 505 return (EIO); 506 goto again; 507 default: /* NOTREACHED */ 508 __assert_unreachable(); 509 } 510 if (dir) { 511 OWLL_WRITE_ONE(lldev, &timing_regular); 512 probed |= 1ull << i; 513 } else { 514 OWLL_WRITE_ZERO(lldev, &timing_regular); 515 } 516 } 517 retries = 0; 518 foundfp(dev, probed); 519 last_mask = probed; 520 prior = last; 521 } 522 ow_release_bus(dev, dev); 523 524 return (0); 525 } 526 527 static int 528 ow_probe(device_t dev) 529 { 530 531 device_set_desc(dev, "1 Wire Bus"); 532 return (BUS_PROBE_GENERIC); 533 } 534 535 static int 536 ow_attach(device_t ndev) 537 { 538 struct ow_softc *sc; 539 540 /* 541 * Find all the devices on the bus. We don't probe / attach them in the 542 * enumeration phase. We do this because we want to allow the probe / 543 * attach routines of the child drivers to have as full an access to the 544 * bus as possible. While we reset things before the next step of the 545 * search (so it would likely be OK to allow access by the clients to 546 * the bus), it is more conservative to find them all, then to do the 547 * attach of the devices. This also allows the child devices to have 548 * more knowledge of the bus. We also ignore errors from the enumeration 549 * because they might happen after we've found a few devices. 550 */ 551 sc = device_get_softc(ndev); 552 sc->dev = ndev; 553 mtx_init(&sc->mtx, device_get_nameunit(sc->dev), "ow", MTX_DEF); 554 ow_enumerate(ndev, ow_search_rom, ow_device_found); 555 return bus_generic_attach(ndev); 556 } 557 558 static int 559 ow_detach(device_t ndev) 560 { 561 device_t *children, child; 562 int nkid, i; 563 struct ow_devinfo *di; 564 struct ow_softc *sc; 565 566 sc = device_get_softc(ndev); 567 /* 568 * detach all the children first. This is blocking until any threads 569 * have stopped, etc. 570 */ 571 bus_generic_detach(ndev); 572 573 /* 574 * We delete all the children, and free up the ivars 575 */ 576 if (device_get_children(ndev, &children, &nkid) != 0) 577 return ENOMEM; 578 for (i = 0; i < nkid; i++) { 579 child = children[i]; 580 di = device_get_ivars(child); 581 free(di, M_OW); 582 device_delete_child(ndev, child); 583 } 584 free(children, M_TEMP); 585 586 OW_LOCK_DESTROY(sc); 587 return 0; 588 } 589 590 static int 591 ow_child_pnpinfo(device_t dev, device_t child, struct sbuf *sb) 592 { 593 struct ow_devinfo *di; 594 595 di = device_get_ivars(child); 596 sbuf_printf(sb, "romid=%8D", &di->romid, ":"); 597 return (0); 598 } 599 600 static int 601 ow_read_ivar(device_t dev, device_t child, int which, uintptr_t *result) 602 { 603 struct ow_devinfo *di; 604 romid_t **ptr; 605 606 di = device_get_ivars(child); 607 switch (which) { 608 case OW_IVAR_FAMILY: 609 *result = di->romid & 0xff; 610 break; 611 case OW_IVAR_ROMID: 612 ptr = (romid_t **)result; 613 *ptr = &di->romid; 614 break; 615 default: 616 return EINVAL; 617 } 618 619 return 0; 620 } 621 622 static int 623 ow_write_ivar(device_t dev, device_t child, int which, uintptr_t value) 624 { 625 626 return EINVAL; 627 } 628 629 static int 630 ow_print_child(device_t ndev, device_t pdev) 631 { 632 int retval = 0; 633 struct ow_devinfo *di; 634 635 di = device_get_ivars(pdev); 636 637 retval += bus_print_child_header(ndev, pdev); 638 retval += printf(" romid %8D", &di->romid, ":"); 639 retval += bus_print_child_footer(ndev, pdev); 640 641 return retval; 642 } 643 644 static void 645 ow_probe_nomatch(device_t ndev, device_t pdev) 646 { 647 struct ow_devinfo *di; 648 649 di = device_get_ivars(pdev); 650 device_printf(ndev, "romid %8D: no driver\n", &di->romid, ":"); 651 } 652 653 static int 654 ow_acquire_bus(device_t ndev, device_t pdev, int how) 655 { 656 struct ow_softc *sc; 657 658 sc = device_get_softc(ndev); 659 OW_ASSERT_UNLOCKED(sc); 660 OW_LOCK(sc); 661 if (sc->owner != NULL) { 662 if (sc->owner == pdev) 663 panic("%s: %s recursively acquiring the bus.\n", 664 device_get_nameunit(ndev), 665 device_get_nameunit(pdev)); 666 if (how == OWN_DONTWAIT) { 667 OW_UNLOCK(sc); 668 return EWOULDBLOCK; 669 } 670 while (sc->owner != NULL) 671 mtx_sleep(sc, &sc->mtx, 0, "owbuswait", 0); 672 } 673 sc->owner = pdev; 674 OW_UNLOCK(sc); 675 676 return 0; 677 } 678 679 static void 680 ow_release_bus(device_t ndev, device_t pdev) 681 { 682 struct ow_softc *sc; 683 684 sc = device_get_softc(ndev); 685 OW_ASSERT_UNLOCKED(sc); 686 OW_LOCK(sc); 687 if (sc->owner == NULL) 688 panic("%s: %s releasing unowned bus.", device_get_nameunit(ndev), 689 device_get_nameunit(pdev)); 690 if (sc->owner != pdev) 691 panic("%s: %s don't own the bus. %s does. game over.", 692 device_get_nameunit(ndev), device_get_nameunit(pdev), 693 device_get_nameunit(sc->owner)); 694 sc->owner = NULL; 695 wakeup(sc); 696 OW_UNLOCK(sc); 697 } 698 699 static device_method_t ow_methods[] = { 700 /* Device interface */ 701 DEVMETHOD(device_probe, ow_probe), 702 DEVMETHOD(device_attach, ow_attach), 703 DEVMETHOD(device_detach, ow_detach), 704 705 /* Bus interface */ 706 DEVMETHOD(bus_child_pnpinfo, ow_child_pnpinfo), 707 DEVMETHOD(bus_read_ivar, ow_read_ivar), 708 DEVMETHOD(bus_write_ivar, ow_write_ivar), 709 DEVMETHOD(bus_print_child, ow_print_child), 710 DEVMETHOD(bus_probe_nomatch, ow_probe_nomatch), 711 712 /* One Wire Network/Transport layer interface */ 713 DEVMETHOD(own_send_command, ow_send_command), 714 DEVMETHOD(own_acquire_bus, ow_acquire_bus), 715 DEVMETHOD(own_release_bus, ow_release_bus), 716 DEVMETHOD(own_crc, ow_crc), 717 { 0, 0 } 718 }; 719 720 static driver_t ow_driver = { 721 "ow", 722 ow_methods, 723 sizeof(struct ow_softc), 724 }; 725 726 DRIVER_MODULE(ow, owc, ow_driver, 0, 0); 727 MODULE_VERSION(ow, 1); 728