1/*- 2 * Copyright (c) 2015 M. Warner Losh <imp@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27#include <sys/cdefs.h> 28__FBSDID("$FreeBSD$"); 29 30#include <sys/param.h> 31#include <sys/systm.h> 32#include <sys/kernel.h> 33 34#include <sys/bus.h> 35#include <sys/errno.h> 36#include <sys/libkern.h> 37#include <sys/malloc.h> 38#include <sys/module.h> 39#include <sys/sysctl.h> 40 41#include <dev/ow/ow.h> 42#include <dev/ow/owll.h> 43#include <dev/ow/own.h> 44 45/* 46 * lldev - link level device 47 * ndev - network / transport device (this module) 48 * pdev - presentation device (children of this module) 49 */ 50 51typedef int ow_enum_fn(device_t, device_t); 52typedef int ow_found_fn(device_t, romid_t); 53 54struct ow_softc 55{ 56 device_t dev; /* Newbus driver back pointer */ 57 struct mtx mtx; /* bus mutex */ 58 device_t owner; /* bus owner, if != NULL */ 59}; 60 61struct ow_devinfo 62{ 63 romid_t romid; 64}; 65 66static int ow_acquire_bus(device_t ndev, device_t pdev, int how); 67static void ow_release_bus(device_t ndev, device_t pdev); 68 69#define OW_LOCK(_sc) mtx_lock(&(_sc)->mtx) 70#define OW_UNLOCK(_sc) mtx_unlock(&(_sc)->mtx) 71#define OW_LOCK_DESTROY(_sc) mtx_destroy(&_sc->mtx) 72#define OW_ASSERT_LOCKED(_sc) mtx_assert(&_sc->mtx, MA_OWNED) 73#define OW_ASSERT_UNLOCKED(_sc) mtx_assert(&_sc->mtx, MA_NOTOWNED) 74 75static MALLOC_DEFINE(M_OW, "ow", "House keeping data for 1wire bus"); 76 77static const struct ow_timing timing_regular_min = { 78 .t_slot = 60, 79 .t_low0 = 60, 80 .t_low1 = 1, 81 .t_release = 0, 82 .t_rec = 1, 83 .t_rdv = 15, /* fixed */ 84 .t_rstl = 480, 85 .t_rsth = 480, 86 .t_pdl = 60, 87 .t_pdh = 15, 88 .t_lowr = 1, 89}; 90 91static const struct ow_timing timing_regular_max = { 92 .t_slot = 120, 93 .t_low0 = 120, 94 .t_low1 = 15, 95 .t_release = 45, 96 .t_rec = 960, /* infinity */ 97 .t_rdv = 15, /* fixed */ 98 .t_rstl = 960, /* infinity */ 99 .t_rsth = 960, /* infinity */ 100 .t_pdl = 240, /* 60us to 240us */ 101 .t_pdh = 60, /* 15us to 60us */ 102 .t_lowr = 15, /* 1us */ 103}; 104 105static struct ow_timing timing_regular = { 106 .t_slot = 60, /* 60 <= t < 120 */ 107 .t_low0 = 60, /* 60 <= t < t_slot < 120 */ 108 .t_low1 = 1, /* 1 <= t < 15 */ 109 .t_release = 45, /* 0 <= t < 45 */ 110 .t_rec = 15, /* 1 <= t < inf */ 111 .t_rdv = 15, /* t == 15 */ 112 .t_rstl = 480, /* 480 <= t < inf */ 113 .t_rsth = 480, /* 480 <= t < inf */ 114 .t_pdl = 60, /* 60 <= t < 240 */ 115 .t_pdh = 60, /* 15 <= t < 60 */ 116 .t_lowr = 1, /* 1 <= t < 15 */ 117}; 118 119/* NB: Untested */ 120static const struct ow_timing timing_overdrive_min = { 121 .t_slot = 6, 122 .t_low0 = 6, 123 .t_low1 = 1, 124 .t_release = 0, 125 .t_rec = 1, 126 .t_rdv = 2, /* fixed */ 127 .t_rstl = 48, 128 .t_rsth = 48, 129 .t_pdl = 8, 130 .t_pdh = 2, 131 .t_lowr = 1, 132}; 133 134static const struct ow_timing timing_overdrive_max = { 135 .t_slot = 16, 136 .t_low0 = 16, 137 .t_low1 = 2, 138 .t_release = 4, 139 .t_rec = 960, /* infinity */ 140 .t_rdv = 2, /* fixed */ 141 .t_rstl = 80, 142 .t_rsth = 960, /* infinity */ 143 .t_pdl = 24, 144 .t_pdh = 6, 145 .t_lowr = 2, 146}; 147 148static struct ow_timing timing_overdrive = { 149 .t_slot = 11, /* 6 <= t < 16 */ 150 .t_low0 = 6, /* 6 <= t < t_slot < 16 */ 151 .t_low1 = 1, /* 1 <= t < 2 */ 152 .t_release = 4, /* 0 <= t < 4 */ 153 .t_rec = 1, /* 1 <= t < inf */ 154 .t_rdv = 2, /* t == 2 */ 155 .t_rstl = 48, /* 48 <= t < 80 */ 156 .t_rsth = 48, /* 48 <= t < inf */ 157 .t_pdl = 8, /* 8 <= t < 24 */ 158 .t_pdh = 2, /* 2 <= t < 6 */ 159 .t_lowr = 1, /* 1 <= t < 2 */ 160}; 161 162SYSCTL_NODE(_hw, OID_AUTO, ow, CTLFLAG_RD, 0, "1-Wire protocol"); 163SYSCTL_NODE(_hw_ow, OID_AUTO, regular, CTLFLAG_RD, 0, 164 "Regular mode timings"); 165SYSCTL_NODE(_hw_ow, OID_AUTO, overdrive, CTLFLAG_RD, 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 } \ 184SYSCTL_PROC(_hw_ow_ ## mode, OID_AUTO, param, \ 185 CTLTYPE_INT | CTLFLAG_RWTUN, 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 193OW_TIMING_SYSCTL(t_slot); 194OW_TIMING_SYSCTL(t_low0); 195OW_TIMING_SYSCTL(t_low1); 196OW_TIMING_SYSCTL(t_release); 197OW_TIMING_SYSCTL(t_rec); 198OW_TIMING_SYSCTL(t_rdv); 199OW_TIMING_SYSCTL(t_rstl); 200OW_TIMING_SYSCTL(t_rsth); 201OW_TIMING_SYSCTL(t_pdl); 202OW_TIMING_SYSCTL(t_pdh); 203OW_TIMING_SYSCTL(t_lowr); 204 205#undef _OW_TIMING_SYSCTL 206#undef OW_TIMING_SYSCTL 207 208static void 209ow_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 220static void 221ow_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 234static int 235ow_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 292static int 293ow_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 304static int 305ow_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 316static int 317ow_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, -1); 325 if (child == NULL) { 326 free(di, M_OW); 327 return ENOMEM; 328 } 329 device_set_ivars(child, di); 330 return (0); 331} 332 333static device_t 334ow_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 */ 359const 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 */ 381static uint8_t 382ow_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 392static int 393ow_check_crc(romid_t romid) 394{ 395 return ow_crc(NULL, NULL, (uint8_t *)&romid, sizeof(romid)) == 0; 396} 397 398static int 399ow_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 421static int 422ow_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 } 441again: 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 527static int 528ow_probe(device_t dev) 529{ 530 531 device_set_desc(dev, "1 Wire Bus"); 532 return (BUS_PROBE_GENERIC); 533} 534 535static int 536ow_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 558static int 559ow_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/* 591 * Not sure this is really needed. I'm having trouble figuring out what 592 * location means in the context of the one wire bus. 593 */ 594static int 595ow_child_location_str(device_t dev, device_t child, char *buf, 596 size_t buflen) 597{ 598 599 *buf = '\0'; 600 return (0); 601} 602 603static int 604ow_child_pnpinfo_str(device_t dev, device_t child, char *buf, 605 size_t buflen) 606{ 607 struct ow_devinfo *di; 608 609 di = device_get_ivars(child); 610 snprintf(buf, buflen, "romid=%8D", &di->romid, ":"); 611 return (0); 612} 613 614static int 615ow_read_ivar(device_t dev, device_t child, int which, uintptr_t *result) 616{ 617 struct ow_devinfo *di; 618 romid_t **ptr; 619 620 di = device_get_ivars(child); 621 switch (which) { 622 case OW_IVAR_FAMILY: 623 *result = di->romid & 0xff; 624 break; 625 case OW_IVAR_ROMID: 626 ptr = (romid_t **)result; 627 *ptr = &di->romid; 628 break; 629 default: 630 return EINVAL; 631 } 632 633 return 0; 634} 635 636static int 637ow_write_ivar(device_t dev, device_t child, int which, uintptr_t value) 638{ 639 640 return EINVAL; 641} 642 643static int 644ow_print_child(device_t ndev, device_t pdev) 645{ 646 int retval = 0; 647 struct ow_devinfo *di; 648 649 di = device_get_ivars(pdev); 650 651 retval += bus_print_child_header(ndev, pdev); 652 retval += printf(" romid %8D", &di->romid, ":"); 653 retval += bus_print_child_footer(ndev, pdev); 654 655 return retval; 656} 657 658static void 659ow_probe_nomatch(device_t ndev, device_t pdev) 660{ 661 struct ow_devinfo *di; 662 663 di = device_get_ivars(pdev); 664 device_printf(ndev, "romid %8D: no driver\n", &di->romid, ":"); 665} 666 667static int 668ow_acquire_bus(device_t ndev, device_t pdev, int how) 669{ 670 struct ow_softc *sc; 671 672 sc = device_get_softc(ndev); 673 OW_ASSERT_UNLOCKED(sc); 674 OW_LOCK(sc); 675 if (sc->owner != NULL) { 676 if (sc->owner == pdev) 677 panic("%s: %s recursively acquiring the bus.\n", 678 device_get_nameunit(ndev), 679 device_get_nameunit(pdev)); 680 if (how == OWN_DONTWAIT) { 681 OW_UNLOCK(sc); 682 return EWOULDBLOCK; 683 } 684 while (sc->owner != NULL) 685 mtx_sleep(sc, &sc->mtx, 0, "owbuswait", 0); 686 } 687 sc->owner = pdev; 688 OW_UNLOCK(sc); 689 690 return 0; 691} 692 693static void 694ow_release_bus(device_t ndev, device_t pdev) 695{ 696 struct ow_softc *sc; 697 698 sc = device_get_softc(ndev); 699 OW_ASSERT_UNLOCKED(sc); 700 OW_LOCK(sc); 701 if (sc->owner == NULL) 702 panic("%s: %s releasing unowned bus.", device_get_nameunit(ndev), 703 device_get_nameunit(pdev)); 704 if (sc->owner != pdev) 705 panic("%s: %s don't own the bus. %s does. game over.", 706 device_get_nameunit(ndev), device_get_nameunit(pdev), 707 device_get_nameunit(sc->owner)); 708 sc->owner = NULL; 709 wakeup(sc); 710 OW_UNLOCK(sc); 711} 712 713devclass_t ow_devclass; 714 715static device_method_t ow_methods[] = { 716 /* Device interface */ 717 DEVMETHOD(device_probe, ow_probe), 718 DEVMETHOD(device_attach, ow_attach), 719 DEVMETHOD(device_detach, ow_detach), 720 721 /* Bus interface */ 722 DEVMETHOD(bus_child_pnpinfo_str, ow_child_pnpinfo_str), 723 DEVMETHOD(bus_child_location_str, ow_child_location_str), 724 DEVMETHOD(bus_read_ivar, ow_read_ivar), 725 DEVMETHOD(bus_write_ivar, ow_write_ivar), 726 DEVMETHOD(bus_print_child, ow_print_child), 727 DEVMETHOD(bus_probe_nomatch, ow_probe_nomatch), 728 729 /* One Wire Network/Transport layer interface */ 730 DEVMETHOD(own_send_command, ow_send_command), 731 DEVMETHOD(own_acquire_bus, ow_acquire_bus), 732 DEVMETHOD(own_release_bus, ow_release_bus), 733 DEVMETHOD(own_crc, ow_crc), 734 { 0, 0 } 735}; 736 737static driver_t ow_driver = { 738 "ow", 739 ow_methods, 740 sizeof(struct ow_softc), 741}; 742 743DRIVER_MODULE(ow, owc, ow_driver, ow_devclass, 0, 0); 744MODULE_VERSION(ow, 1); 745