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sys/xen/xenbus/xenbusb.c
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1 /****************************************************************************** 2 * Copyright (C) 2010 Spectra Logic Corporation 3 * Copyright (C) 2008 Doug Rabson 4 * Copyright (C) 2005 Rusty Russell, IBM Corporation 5 * Copyright (C) 2005 Mike Wray, Hewlett-Packard 6 * Copyright (C) 2005 XenSource Ltd 7 * 8 * This file may be distributed separately from the Linux kernel, or 9 * incorporated into other software packages, subject to the following license: 10 * 11 * Permission is hereby granted, free of charge, to any person obtaining a copy 12 * of this source file (the "Software"), to deal in the Software without 13 * restriction, including without limitation the rights to use, copy, modify, 14 * merge, publish, distribute, sublicense, and/or sell copies of the Software, 15 * and to permit persons to whom the Software is furnished to do so, subject to 16 * the following conditions: 17 * 18 * The above copyright notice and this permission notice shall be included in 19 * all copies or substantial portions of the Software. 20 * 21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 22 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 23 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 24 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 25 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 26 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 27 * IN THE SOFTWARE. 28 */ 29 30 /** 31 * \file xenbusb.c 32 * 33 * \brief Shared support functions for managing the NewBus busses that contain 34 * Xen front and back end device instances. 35 * 36 * The NewBus implementation of XenBus attaches a xenbusb_front and xenbusb_back 37 * child bus to the xenstore device. This strategy allows the small differences 38 * in the handling of XenBus operations for front and back devices to be handled 39 * as overrides in xenbusb_front/back.c. Front and back specific device 40 * classes are also provided so device drivers can register for the devices they 41 * can handle without the need to filter within their probe routines. The 42 * net result is a device hierarchy that might look like this: 43 * 44 * xenstore0/ 45 * xenbusb_front0/ 46 * xn0 47 * xbd0 48 * xbd1 49 * xenbusb_back0/ 50 * xbbd0 51 * xnb0 52 * xnb1 53 */ 54 #include <sys/cdefs.h> 55 __FBSDID("$FreeBSD: releng/11.2/sys/xen/xenbus/xenbusb.c 315668 2017-03-21 08:38:12Z royger $"); 56 57 #include <sys/param.h> 58 #include <sys/bus.h> 59 #include <sys/kernel.h> 60 #include <sys/lock.h> 61 #include <sys/malloc.h> 62 #include <sys/module.h> 63 #include <sys/sbuf.h> 64 #include <sys/sysctl.h> 65 #include <sys/syslog.h> 66 #include <sys/systm.h> 67 #include <sys/sx.h> 68 #include <sys/taskqueue.h> 69 70 #include <machine/xen/xen-os.h> 71 #include <machine/stdarg.h> 72 73 #include <xen/gnttab.h> 74 #include <xen/xenstore/xenstorevar.h> 75 #include <xen/xenbus/xenbusb.h> 76 #include <xen/xenbus/xenbusvar.h> 77 78 /*------------------------- Private Functions --------------------------------*/ 79 /** 80 * \brief Deallocate XenBus device instance variables. 81 * 82 * \param ivars The instance variable block to free. 83 */ 84 static void 85 xenbusb_free_child_ivars(struct xenbus_device_ivars *ivars) 86 { 87 if (ivars->xd_otherend_watch.node != NULL) { 88 xs_unregister_watch(&ivars->xd_otherend_watch); 89 free(ivars->xd_otherend_watch.node, M_XENBUS); 90 ivars->xd_otherend_watch.node = NULL; 91 } 92 93 if (ivars->xd_local_watch.node != NULL) { 94 xs_unregister_watch(&ivars->xd_local_watch); 95 ivars->xd_local_watch.node = NULL; 96 } 97 98 if (ivars->xd_node != NULL) { 99 free(ivars->xd_node, M_XENBUS); 100 ivars->xd_node = NULL; 101 } 102 ivars->xd_node_len = 0; 103 104 if (ivars->xd_type != NULL) { 105 free(ivars->xd_type, M_XENBUS); 106 ivars->xd_type = NULL; 107 } 108 109 if (ivars->xd_otherend_path != NULL) { 110 free(ivars->xd_otherend_path, M_XENBUS); 111 ivars->xd_otherend_path = NULL; 112 } 113 ivars->xd_otherend_path_len = 0; 114 115 free(ivars, M_XENBUS); 116 } 117 118 /** 119 * XenBus watch callback registered against the "state" XenStore 120 * node of the other-end of a split device connection. 121 * 122 * This callback is invoked whenever the state of a device instance's 123 * peer changes. 124 * 125 * \param watch The xs_watch object used to register this callback 126 * function. 127 * \param vec An array of pointers to NUL terminated strings containing 128 * watch event data. The vector should be indexed via the 129 * xs_watch_type enum in xs_wire.h. 130 * \param vec_size The number of elements in vec. 131 */ 132 static void 133 xenbusb_otherend_watch_cb(struct xs_watch *watch, const char **vec, 134 unsigned int vec_size __unused) 135 { 136 struct xenbus_device_ivars *ivars; 137 device_t child; 138 device_t bus; 139 const char *path; 140 enum xenbus_state newstate; 141 142 ivars = (struct xenbus_device_ivars *)watch->callback_data; 143 child = ivars->xd_dev; 144 bus = device_get_parent(child); 145 146 path = vec[XS_WATCH_PATH]; 147 if (ivars->xd_otherend_path == NULL 148 || strncmp(ivars->xd_otherend_path, path, ivars->xd_otherend_path_len)) 149 return; 150 151 newstate = xenbus_read_driver_state(ivars->xd_otherend_path); 152 XENBUSB_OTHEREND_CHANGED(bus, child, newstate); 153 } 154 155 /** 156 * XenBus watch callback registered against the XenStore sub-tree 157 * represnting the local half of a split device connection. 158 * 159 * This callback is invoked whenever any XenStore data in the subtree 160 * is modified, either by us or another privledged domain. 161 * 162 * \param watch The xs_watch object used to register this callback 163 * function. 164 * \param vec An array of pointers to NUL terminated strings containing 165 * watch event data. The vector should be indexed via the 166 * xs_watch_type enum in xs_wire.h. 167 * \param vec_size The number of elements in vec. 168 * 169 */ 170 static void 171 xenbusb_local_watch_cb(struct xs_watch *watch, const char **vec, 172 unsigned int vec_size __unused) 173 { 174 struct xenbus_device_ivars *ivars; 175 device_t child; 176 device_t bus; 177 const char *path; 178 179 ivars = (struct xenbus_device_ivars *)watch->callback_data; 180 child = ivars->xd_dev; 181 bus = device_get_parent(child); 182 183 path = vec[XS_WATCH_PATH]; 184 if (ivars->xd_node == NULL 185 || strncmp(ivars->xd_node, path, ivars->xd_node_len)) 186 return; 187 188 XENBUSB_LOCALEND_CHANGED(bus, child, &path[ivars->xd_node_len]); 189 } 190 191 /** 192 * Search our internal record of configured devices (not the XenStore) 193 * to determine if the XenBus device indicated by \a node is known to 194 * the system. 195 * 196 * \param dev The XenBus bus instance to search for device children. 197 * \param node The XenStore node path for the device to find. 198 * 199 * \return The device_t of the found device if any, or NULL. 200 * 201 * \note device_t is a pointer type, so it can be compared against 202 * NULL for validity. 203 */ 204 static device_t 205 xenbusb_device_exists(device_t dev, const char *node) 206 { 207 device_t *kids; 208 device_t result; 209 struct xenbus_device_ivars *ivars; 210 int i, count; 211 212 if (device_get_children(dev, &kids, &count)) 213 return (FALSE); 214 215 result = NULL; 216 for (i = 0; i < count; i++) { 217 ivars = device_get_ivars(kids[i]); 218 if (!strcmp(ivars->xd_node, node)) { 219 result = kids[i]; 220 break; 221 } 222 } 223 free(kids, M_TEMP); 224 225 return (result); 226 } 227 228 static void 229 xenbusb_delete_child(device_t dev, device_t child) 230 { 231 struct xenbus_device_ivars *ivars; 232 233 ivars = device_get_ivars(child); 234 235 /* 236 * We no longer care about the otherend of the 237 * connection. Cancel the watches now so that we 238 * don't try to handle an event for a partially 239 * detached child. 240 */ 241 if (ivars->xd_otherend_watch.node != NULL) 242 xs_unregister_watch(&ivars->xd_otherend_watch); 243 if (ivars->xd_local_watch.node != NULL) 244 xs_unregister_watch(&ivars->xd_local_watch); 245 246 device_delete_child(dev, child); 247 xenbusb_free_child_ivars(ivars); 248 } 249 250 /** 251 * \param dev The NewBus device representing this XenBus bus. 252 * \param child The NewBus device representing a child of dev%'s XenBus bus. 253 */ 254 static void 255 xenbusb_verify_device(device_t dev, device_t child) 256 { 257 if (xs_exists(XST_NIL, xenbus_get_node(child), "") == 0) { 258 259 /* 260 * Device tree has been removed from Xenbus. 261 * Tear down the device. 262 */ 263 xenbusb_delete_child(dev, child); 264 } 265 } 266 267 /** 268 * \brief Enumerate the devices on a XenBus bus and register them with 269 * the NewBus device tree. 270 * 271 * xenbusb_enumerate_bus() will create entries (in state DS_NOTPRESENT) 272 * for nodes that appear in the XenStore, but will not invoke probe/attach 273 * operations on drivers. Probe/Attach processing must be separately 274 * performed via an invocation of xenbusb_probe_children(). This is usually 275 * done via the xbs_probe_children task. 276 * 277 * \param xbs XenBus Bus device softc of the owner of the bus to enumerate. 278 * 279 * \return On success, 0. Otherwise an errno value indicating the 280 * type of failure. 281 */ 282 static int 283 xenbusb_enumerate_bus(struct xenbusb_softc *xbs) 284 { 285 const char **types; 286 u_int type_idx; 287 u_int type_count; 288 int error; 289 290 error = xs_directory(XST_NIL, xbs->xbs_node, "", &type_count, &types); 291 if (error) 292 return (error); 293 294 for (type_idx = 0; type_idx < type_count; type_idx++) 295 XENBUSB_ENUMERATE_TYPE(xbs->xbs_dev, types[type_idx]); 296 297 free(types, M_XENSTORE); 298 299 return (0); 300 } 301 302 /** 303 * Handler for all generic XenBus device systcl nodes. 304 */ 305 static int 306 xenbusb_device_sysctl_handler(SYSCTL_HANDLER_ARGS) 307 { 308 device_t dev; 309 const char *value; 310 311 dev = (device_t)arg1; 312 switch (arg2) { 313 case XENBUS_IVAR_NODE: 314 value = xenbus_get_node(dev); 315 break; 316 case XENBUS_IVAR_TYPE: 317 value = xenbus_get_type(dev); 318 break; 319 case XENBUS_IVAR_STATE: 320 value = xenbus_strstate(xenbus_get_state(dev)); 321 break; 322 case XENBUS_IVAR_OTHEREND_ID: 323 return (sysctl_handle_int(oidp, NULL, 324 xenbus_get_otherend_id(dev), 325 req)); 326 /* NOTREACHED */ 327 case XENBUS_IVAR_OTHEREND_PATH: 328 value = xenbus_get_otherend_path(dev); 329 break; 330 default: 331 return (EINVAL); 332 } 333 return (SYSCTL_OUT_STR(req, value)); 334 } 335 336 /** 337 * Create read-only systcl nodes for xenbusb device ivar data. 338 * 339 * \param dev The XenBus device instance to register with sysctl. 340 */ 341 static void 342 xenbusb_device_sysctl_init(device_t dev) 343 { 344 struct sysctl_ctx_list *ctx; 345 struct sysctl_oid *tree; 346 347 ctx = device_get_sysctl_ctx(dev); 348 tree = device_get_sysctl_tree(dev); 349 350 SYSCTL_ADD_PROC(ctx, 351 SYSCTL_CHILDREN(tree), 352 OID_AUTO, 353 "xenstore_path", 354 CTLTYPE_STRING | CTLFLAG_RD, 355 dev, 356 XENBUS_IVAR_NODE, 357 xenbusb_device_sysctl_handler, 358 "A", 359 "XenStore path to device"); 360 361 SYSCTL_ADD_PROC(ctx, 362 SYSCTL_CHILDREN(tree), 363 OID_AUTO, 364 "xenbus_dev_type", 365 CTLTYPE_STRING | CTLFLAG_RD, 366 dev, 367 XENBUS_IVAR_TYPE, 368 xenbusb_device_sysctl_handler, 369 "A", 370 "XenBus device type"); 371 372 SYSCTL_ADD_PROC(ctx, 373 SYSCTL_CHILDREN(tree), 374 OID_AUTO, 375 "xenbus_connection_state", 376 CTLTYPE_STRING | CTLFLAG_RD, 377 dev, 378 XENBUS_IVAR_STATE, 379 xenbusb_device_sysctl_handler, 380 "A", 381 "XenBus state of peer connection"); 382 383 SYSCTL_ADD_PROC(ctx, 384 SYSCTL_CHILDREN(tree), 385 OID_AUTO, 386 "xenbus_peer_domid", 387 CTLTYPE_INT | CTLFLAG_RD, 388 dev, 389 XENBUS_IVAR_OTHEREND_ID, 390 xenbusb_device_sysctl_handler, 391 "I", 392 "Xen domain ID of peer"); 393 394 SYSCTL_ADD_PROC(ctx, 395 SYSCTL_CHILDREN(tree), 396 OID_AUTO, 397 "xenstore_peer_path", 398 CTLTYPE_STRING | CTLFLAG_RD, 399 dev, 400 XENBUS_IVAR_OTHEREND_PATH, 401 xenbusb_device_sysctl_handler, 402 "A", 403 "XenStore path to peer device"); 404 } 405 406 /** 407 * \brief Decrement the number of XenBus child devices in the 408 * connecting state by one and release the xbs_attch_ch 409 * interrupt configuration hook if the connecting count 410 * drops to zero. 411 * 412 * \param xbs XenBus Bus device softc of the owner of the bus to enumerate. 413 */ 414 static void 415 xenbusb_release_confighook(struct xenbusb_softc *xbs) 416 { 417 mtx_lock(&xbs->xbs_lock); 418 KASSERT(xbs->xbs_connecting_children > 0, 419 ("Connecting device count error\n")); 420 xbs->xbs_connecting_children--; 421 if (xbs->xbs_connecting_children == 0 422 && (xbs->xbs_flags & XBS_ATTACH_CH_ACTIVE) != 0) { 423 xbs->xbs_flags &= ~XBS_ATTACH_CH_ACTIVE; 424 mtx_unlock(&xbs->xbs_lock); 425 config_intrhook_disestablish(&xbs->xbs_attach_ch); 426 } else { 427 mtx_unlock(&xbs->xbs_lock); 428 } 429 } 430 431 /** 432 * \brief Verify the existance of attached device instances and perform 433 * probe/attach processing for newly arrived devices. 434 * 435 * \param dev The NewBus device representing this XenBus bus. 436 * 437 * \return On success, 0. Otherwise an errno value indicating the 438 * type of failure. 439 */ 440 static int 441 xenbusb_probe_children(device_t dev) 442 { 443 device_t *kids; 444 struct xenbus_device_ivars *ivars; 445 int i, count, error; 446 447 if (device_get_children(dev, &kids, &count) == 0) { 448 for (i = 0; i < count; i++) { 449 if (device_get_state(kids[i]) != DS_NOTPRESENT) { 450 /* 451 * We already know about this one. 452 * Make sure it's still here. 453 */ 454 xenbusb_verify_device(dev, kids[i]); 455 continue; 456 } 457 458 error = device_probe_and_attach(kids[i]); 459 if (error == ENXIO) { 460 struct xenbusb_softc *xbs; 461 462 /* 463 * We don't have a PV driver for this device. 464 * However, an emulated device we do support 465 * may share this backend. Hide the node from 466 * XenBus until the next rescan, but leave it's 467 * state unchanged so we don't inadvertently 468 * prevent attachment of any emulated device. 469 */ 470 xenbusb_delete_child(dev, kids[i]); 471 472 /* 473 * Since the XenStore state of this device 474 * still indicates a pending attach, manually 475 * release it's hold on the boot process. 476 */ 477 xbs = device_get_softc(dev); 478 xenbusb_release_confighook(xbs); 479 480 continue; 481 } else if (error) { 482 /* 483 * Transition device to the closed state 484 * so the world knows that attachment will 485 * not occur. 486 */ 487 xenbus_set_state(kids[i], XenbusStateClosed); 488 489 /* 490 * Remove our record of this device. 491 * So long as it remains in the closed 492 * state in the XenStore, we will not find 493 * it again. The state will only change 494 * if the control domain actively reconfigures 495 * this device. 496 */ 497 xenbusb_delete_child(dev, kids[i]); 498 499 continue; 500 } 501 /* 502 * Augment default newbus provided dynamic sysctl 503 * variables with the standard ivar contents of 504 * XenBus devices. 505 */ 506 xenbusb_device_sysctl_init(kids[i]); 507 508 /* 509 * Now that we have a driver managing this device 510 * that can receive otherend state change events, 511 * hook up a watch for them. 512 */ 513 ivars = device_get_ivars(kids[i]); 514 xs_register_watch(&ivars->xd_otherend_watch); 515 xs_register_watch(&ivars->xd_local_watch); 516 } 517 free(kids, M_TEMP); 518 } 519 520 return (0); 521 } 522 523 /** 524 * \brief Task callback function to perform XenBus probe operations 525 * from a known safe context. 526 * 527 * \param arg The NewBus device_t representing the bus instance to 528 * on which to perform probe processing. 529 * \param pending The number of times this task was queued before it could 530 * be run. 531 */ 532 static void 533 xenbusb_probe_children_cb(void *arg, int pending __unused) 534 { 535 device_t dev = (device_t)arg; 536 537 /* 538 * Hold Giant until the Giant free newbus changes are committed. 539 */ 540 mtx_lock(&Giant); 541 xenbusb_probe_children(dev); 542 mtx_unlock(&Giant); 543 } 544 545 /** 546 * \brief XenStore watch callback for the root node of the XenStore 547 * subtree representing a XenBus. 548 * 549 * This callback performs, or delegates to the xbs_probe_children task, 550 * all processing necessary to handle dynmaic device arrival and departure 551 * events from a XenBus. 552 * 553 * \param watch The XenStore watch object associated with this callback. 554 * \param vec The XenStore watch event data. 555 * \param len The number of fields in the event data stream. 556 */ 557 static void 558 xenbusb_devices_changed(struct xs_watch *watch, const char **vec, 559 unsigned int len) 560 { 561 struct xenbusb_softc *xbs; 562 device_t dev; 563 char *node; 564 char *type; 565 char *id; 566 char *p; 567 u_int component; 568 569 xbs = (struct xenbusb_softc *)watch->callback_data; 570 dev = xbs->xbs_dev; 571 572 if (len <= XS_WATCH_PATH) { 573 device_printf(dev, "xenbusb_devices_changed: " 574 "Short Event Data.\n"); 575 return; 576 } 577 578 node = strdup(vec[XS_WATCH_PATH], M_XENBUS); 579 p = strchr(node, '/'); 580 if (p == NULL) 581 goto out; 582 *p = 0; 583 type = p + 1; 584 585 p = strchr(type, '/'); 586 if (p == NULL) 587 goto out; 588 *p++ = 0; 589 590 /* 591 * Extract the device ID. A device ID has one or more path 592 * components separated by the '/' character. 593 * 594 * e.g. "<frontend vm id>/<frontend dev id>" for backend devices. 595 */ 596 id = p; 597 for (component = 0; component < xbs->xbs_id_components; component++) { 598 p = strchr(p, '/'); 599 if (p == NULL) 600 break; 601 p++; 602 } 603 if (p != NULL) 604 *p = 0; 605 606 if (*id != 0 && component >= xbs->xbs_id_components - 1) { 607 xenbusb_add_device(xbs->xbs_dev, type, id); 608 taskqueue_enqueue(taskqueue_thread, &xbs->xbs_probe_children); 609 } 610 out: 611 free(node, M_XENBUS); 612 } 613 614 /** 615 * \brief Interrupt configuration hook callback associated with xbs_attch_ch. 616 * 617 * Since interrupts are always functional at the time of XenBus configuration, 618 * there is nothing to be done when the callback occurs. This hook is only 619 * registered to hold up boot processing while XenBus devices come online. 620 * 621 * \param arg Unused configuration hook callback argument. 622 */ 623 static void 624 xenbusb_nop_confighook_cb(void *arg __unused) 625 { 626 } 627 628 /*--------------------------- Public Functions -------------------------------*/ 629 /*--------- API comments for these methods can be found in xenbusb.h ---------*/ 630 void 631 xenbusb_identify(driver_t *driver __unused, device_t parent) 632 { 633 /* 634 * A single instance of each bus type for which we have a driver 635 * is always present in a system operating under Xen. 636 */ 637 BUS_ADD_CHILD(parent, 0, driver->name, 0); 638 } 639 640 int 641 xenbusb_add_device(device_t dev, const char *type, const char *id) 642 { 643 struct xenbusb_softc *xbs; 644 struct sbuf *devpath_sbuf; 645 char *devpath; 646 struct xenbus_device_ivars *ivars; 647 int error; 648 649 xbs = device_get_softc(dev); 650 devpath_sbuf = sbuf_new_auto(); 651 sbuf_printf(devpath_sbuf, "%s/%s/%s", xbs->xbs_node, type, id); 652 sbuf_finish(devpath_sbuf); 653 devpath = sbuf_data(devpath_sbuf); 654 655 ivars = malloc(sizeof(*ivars), M_XENBUS, M_ZERO|M_WAITOK); 656 error = ENXIO; 657 658 if (xs_exists(XST_NIL, devpath, "") != 0) { 659 device_t child; 660 enum xenbus_state state; 661 char *statepath; 662 663 child = xenbusb_device_exists(dev, devpath); 664 if (child != NULL) { 665 /* 666 * We are already tracking this node 667 */ 668 error = 0; 669 goto out; 670 } 671 672 state = xenbus_read_driver_state(devpath); 673 if (state != XenbusStateInitialising) { 674 /* 675 * Device is not new, so ignore it. This can 676 * happen if a device is going away after 677 * switching to Closed. 678 */ 679 printf("xenbusb_add_device: Device %s ignored. " 680 "State %d\n", devpath, state); 681 error = 0; 682 goto out; 683 } 684 685 sx_init(&ivars->xd_lock, "xdlock"); 686 ivars->xd_flags = XDF_CONNECTING; 687 ivars->xd_node = strdup(devpath, M_XENBUS); 688 ivars->xd_node_len = strlen(devpath); 689 ivars->xd_type = strdup(type, M_XENBUS); 690 ivars->xd_state = XenbusStateInitialising; 691 692 error = XENBUSB_GET_OTHEREND_NODE(dev, ivars); 693 if (error) { 694 printf("xenbus_update_device: %s no otherend id\n", 695 devpath); 696 goto out; 697 } 698 699 statepath = malloc(ivars->xd_otherend_path_len 700 + strlen("/state") + 1, M_XENBUS, M_WAITOK); 701 sprintf(statepath, "%s/state", ivars->xd_otherend_path); 702 ivars->xd_otherend_watch.node = statepath; 703 ivars->xd_otherend_watch.callback = xenbusb_otherend_watch_cb; 704 ivars->xd_otherend_watch.callback_data = (uintptr_t)ivars; 705 706 ivars->xd_local_watch.node = ivars->xd_node; 707 ivars->xd_local_watch.callback = xenbusb_local_watch_cb; 708 ivars->xd_local_watch.callback_data = (uintptr_t)ivars; 709 710 mtx_lock(&xbs->xbs_lock); 711 xbs->xbs_connecting_children++; 712 mtx_unlock(&xbs->xbs_lock); 713 714 child = device_add_child(dev, NULL, -1); 715 ivars->xd_dev = child; 716 device_set_ivars(child, ivars); 717 } 718 719 out: 720 sbuf_delete(devpath_sbuf); 721 if (error != 0) 722 xenbusb_free_child_ivars(ivars); 723 724 return (error); 725 } 726 727 int 728 xenbusb_attach(device_t dev, char *bus_node, u_int id_components) 729 { 730 struct xenbusb_softc *xbs; 731 732 xbs = device_get_softc(dev); 733 mtx_init(&xbs->xbs_lock, "xenbusb softc lock", NULL, MTX_DEF); 734 xbs->xbs_node = bus_node; 735 xbs->xbs_id_components = id_components; 736 xbs->xbs_dev = dev; 737 738 /* 739 * Since XenBus busses are attached to the XenStore, and 740 * the XenStore does not probe children until after interrupt 741 * services are available, this config hook is used solely 742 * to ensure that the remainder of the boot process (e.g. 743 * mount root) is deferred until child devices are adequately 744 * probed. We unblock the boot process as soon as the 745 * connecting child count in our softc goes to 0. 746 */ 747 xbs->xbs_attach_ch.ich_func = xenbusb_nop_confighook_cb; 748 xbs->xbs_attach_ch.ich_arg = dev; 749 config_intrhook_establish(&xbs->xbs_attach_ch); 750 xbs->xbs_flags |= XBS_ATTACH_CH_ACTIVE; 751 xbs->xbs_connecting_children = 1; 752 753 /* 754 * The subtree for this bus type may not yet exist 755 * causing initial enumeration to fail. We still 756 * want to return success from our attach though 757 * so that we are ready to handle devices for this 758 * bus when they are dynamically attached to us 759 * by a Xen management action. 760 */ 761 (void)xenbusb_enumerate_bus(xbs); 762 xenbusb_probe_children(dev); 763 764 xbs->xbs_device_watch.node = bus_node; 765 xbs->xbs_device_watch.callback = xenbusb_devices_changed; 766 xbs->xbs_device_watch.callback_data = (uintptr_t)xbs; 767 768 TASK_INIT(&xbs->xbs_probe_children, 0, xenbusb_probe_children_cb, dev); 769 770 xs_register_watch(&xbs->xbs_device_watch); 771 772 xenbusb_release_confighook(xbs); 773 774 return (0); 775 } 776 777 int 778 xenbusb_resume(device_t dev) 779 { 780 device_t *kids; 781 struct xenbus_device_ivars *ivars; 782 int i, count, error; 783 char *statepath; 784 785 /* 786 * We must re-examine each device and find the new path for 787 * its backend. 788 */ 789 if (device_get_children(dev, &kids, &count) == 0) { 790 for (i = 0; i < count; i++) { 791 if (device_get_state(kids[i]) == DS_NOTPRESENT) 792 continue; 793 794 if (xen_suspend_cancelled) { 795 DEVICE_RESUME(kids[i]); 796 continue; 797 } 798 799 ivars = device_get_ivars(kids[i]); 800 801 xs_unregister_watch(&ivars->xd_otherend_watch); 802 xenbus_set_state(kids[i], XenbusStateInitialising); 803 804 /* 805 * Find the new backend details and 806 * re-register our watch. 807 */ 808 error = XENBUSB_GET_OTHEREND_NODE(dev, ivars); 809 if (error) 810 return (error); 811 812 statepath = malloc(ivars->xd_otherend_path_len 813 + strlen("/state") + 1, M_XENBUS, M_WAITOK); 814 sprintf(statepath, "%s/state", ivars->xd_otherend_path); 815 816 free(ivars->xd_otherend_watch.node, M_XENBUS); 817 ivars->xd_otherend_watch.node = statepath; 818 819 DEVICE_RESUME(kids[i]); 820 821 xs_register_watch(&ivars->xd_otherend_watch); 822 #if 0 823 /* 824 * Can't do this yet since we are running in 825 * the xenwatch thread and if we sleep here, 826 * we will stop delivering watch notifications 827 * and the device will never come back online. 828 */ 829 sx_xlock(&ivars->xd_lock); 830 while (ivars->xd_state != XenbusStateClosed 831 && ivars->xd_state != XenbusStateConnected) 832 sx_sleep(&ivars->xd_state, &ivars->xd_lock, 833 0, "xdresume", 0); 834 sx_xunlock(&ivars->xd_lock); 835 #endif 836 } 837 free(kids, M_TEMP); 838 } 839 840 return (0); 841 } 842 843 int 844 xenbusb_print_child(device_t dev, device_t child) 845 { 846 struct xenbus_device_ivars *ivars = device_get_ivars(child); 847 int retval = 0; 848 849 retval += bus_print_child_header(dev, child); 850 retval += printf(" at %s", ivars->xd_node); 851 retval += bus_print_child_footer(dev, child); 852 853 return (retval); 854 } 855 856 int 857 xenbusb_read_ivar(device_t dev, device_t child, int index, uintptr_t *result) 858 { 859 struct xenbus_device_ivars *ivars = device_get_ivars(child); 860 861 switch (index) { 862 case XENBUS_IVAR_NODE: 863 *result = (uintptr_t) ivars->xd_node; 864 return (0); 865 866 case XENBUS_IVAR_TYPE: 867 *result = (uintptr_t) ivars->xd_type; 868 return (0); 869 870 case XENBUS_IVAR_STATE: 871 *result = (uintptr_t) ivars->xd_state; 872 return (0); 873 874 case XENBUS_IVAR_OTHEREND_ID: 875 *result = (uintptr_t) ivars->xd_otherend_id; 876 return (0); 877 878 case XENBUS_IVAR_OTHEREND_PATH: 879 *result = (uintptr_t) ivars->xd_otherend_path; 880 return (0); 881 } 882 883 return (ENOENT); 884 } 885 886 int 887 xenbusb_write_ivar(device_t dev, device_t child, int index, uintptr_t value) 888 { 889 struct xenbus_device_ivars *ivars = device_get_ivars(child); 890 enum xenbus_state newstate; 891 int currstate; 892 893 switch (index) { 894 case XENBUS_IVAR_STATE: 895 { 896 int error; 897 898 newstate = (enum xenbus_state)value; 899 sx_xlock(&ivars->xd_lock); 900 if (ivars->xd_state == newstate) { 901 error = 0; 902 goto out; 903 } 904 905 error = xs_scanf(XST_NIL, ivars->xd_node, "state", 906 NULL, "%d", &currstate); 907 if (error) 908 goto out; 909 910 do { 911 error = xs_printf(XST_NIL, ivars->xd_node, "state", 912 "%d", newstate); 913 } while (error == EAGAIN); 914 if (error) { 915 /* 916 * Avoid looping through xenbus_dev_fatal() 917 * which calls xenbus_write_ivar to set the 918 * state to closing. 919 */ 920 if (newstate != XenbusStateClosing) 921 xenbus_dev_fatal(dev, error, 922 "writing new state"); 923 goto out; 924 } 925 ivars->xd_state = newstate; 926 927 if ((ivars->xd_flags & XDF_CONNECTING) != 0 928 && (newstate == XenbusStateClosed 929 || newstate == XenbusStateConnected)) { 930 struct xenbusb_softc *xbs; 931 932 ivars->xd_flags &= ~XDF_CONNECTING; 933 xbs = device_get_softc(dev); 934 xenbusb_release_confighook(xbs); 935 } 936 937 wakeup(&ivars->xd_state); 938 out: 939 sx_xunlock(&ivars->xd_lock); 940 return (error); 941 } 942 943 case XENBUS_IVAR_NODE: 944 case XENBUS_IVAR_TYPE: 945 case XENBUS_IVAR_OTHEREND_ID: 946 case XENBUS_IVAR_OTHEREND_PATH: 947 /* 948 * These variables are read-only. 949 */ 950 return (EINVAL); 951 } 952 953 return (ENOENT); 954 } 955 956 void 957 xenbusb_otherend_changed(device_t bus, device_t child, enum xenbus_state state) 958 { 959 XENBUS_OTHEREND_CHANGED(child, state); 960 } 961 962 void 963 xenbusb_localend_changed(device_t bus, device_t child, const char *path) 964 { 965 966 if (strcmp(path, "/state") != 0) { 967 struct xenbus_device_ivars *ivars; 968 969 ivars = device_get_ivars(child); 970 sx_xlock(&ivars->xd_lock); 971 ivars->xd_state = xenbus_read_driver_state(ivars->xd_node); 972 sx_xunlock(&ivars->xd_lock); 973 } 974 XENBUS_LOCALEND_CHANGED(child, path); 975 }
Cache object: 727f3ff30dd062822ea6650db9fc0b97
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