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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/10.1/sys/xen/xenbus/xenbusb.c 250917 2013-05-22 19:22:44Z gibbs $"); 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(req, value, strlen(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 *bus; 565 char *type; 566 char *id; 567 char *p; 568 u_int component; 569 570 xbs = (struct xenbusb_softc *)watch->callback_data; 571 dev = xbs->xbs_dev; 572 573 if (len <= XS_WATCH_PATH) { 574 device_printf(dev, "xenbusb_devices_changed: " 575 "Short Event Data.\n"); 576 return; 577 } 578 579 node = strdup(vec[XS_WATCH_PATH], M_XENBUS); 580 p = strchr(node, '/'); 581 if (p == NULL) 582 goto out; 583 bus = node; 584 *p = 0; 585 type = p + 1; 586 587 p = strchr(type, '/'); 588 if (p == NULL) 589 goto out; 590 *p++ = 0; 591 592 /* 593 * Extract the device ID. A device ID has one or more path 594 * components separated by the '/' character. 595 * 596 * e.g. "<frontend vm id>/<frontend dev id>" for backend devices. 597 */ 598 id = p; 599 for (component = 0; component < xbs->xbs_id_components; component++) { 600 p = strchr(p, '/'); 601 if (p == NULL) 602 break; 603 p++; 604 } 605 if (p != NULL) 606 *p = 0; 607 608 if (*id != 0 && component >= xbs->xbs_id_components - 1) { 609 xenbusb_add_device(xbs->xbs_dev, type, id); 610 taskqueue_enqueue(taskqueue_thread, &xbs->xbs_probe_children); 611 } 612 out: 613 free(node, M_XENBUS); 614 } 615 616 /** 617 * \brief Interrupt configuration hook callback associated with xbs_attch_ch. 618 * 619 * Since interrupts are always functional at the time of XenBus configuration, 620 * there is nothing to be done when the callback occurs. This hook is only 621 * registered to hold up boot processing while XenBus devices come online. 622 * 623 * \param arg Unused configuration hook callback argument. 624 */ 625 static void 626 xenbusb_nop_confighook_cb(void *arg __unused) 627 { 628 } 629 630 /*--------------------------- Public Functions -------------------------------*/ 631 /*--------- API comments for these methods can be found in xenbusb.h ---------*/ 632 void 633 xenbusb_identify(driver_t *driver __unused, device_t parent) 634 { 635 /* 636 * A single instance of each bus type for which we have a driver 637 * is always present in a system operating under Xen. 638 */ 639 BUS_ADD_CHILD(parent, 0, driver->name, 0); 640 } 641 642 int 643 xenbusb_add_device(device_t dev, const char *type, const char *id) 644 { 645 struct xenbusb_softc *xbs; 646 struct sbuf *devpath_sbuf; 647 char *devpath; 648 struct xenbus_device_ivars *ivars; 649 int error; 650 651 xbs = device_get_softc(dev); 652 devpath_sbuf = sbuf_new_auto(); 653 sbuf_printf(devpath_sbuf, "%s/%s/%s", xbs->xbs_node, type, id); 654 sbuf_finish(devpath_sbuf); 655 devpath = sbuf_data(devpath_sbuf); 656 657 ivars = malloc(sizeof(*ivars), M_XENBUS, M_ZERO|M_WAITOK); 658 error = ENXIO; 659 660 if (xs_exists(XST_NIL, devpath, "") != 0) { 661 device_t child; 662 enum xenbus_state state; 663 char *statepath; 664 665 child = xenbusb_device_exists(dev, devpath); 666 if (child != NULL) { 667 /* 668 * We are already tracking this node 669 */ 670 error = 0; 671 goto out; 672 } 673 674 state = xenbus_read_driver_state(devpath); 675 if (state != XenbusStateInitialising) { 676 /* 677 * Device is not new, so ignore it. This can 678 * happen if a device is going away after 679 * switching to Closed. 680 */ 681 printf("xenbusb_add_device: Device %s ignored. " 682 "State %d\n", devpath, state); 683 error = 0; 684 goto out; 685 } 686 687 sx_init(&ivars->xd_lock, "xdlock"); 688 ivars->xd_flags = XDF_CONNECTING; 689 ivars->xd_node = strdup(devpath, M_XENBUS); 690 ivars->xd_node_len = strlen(devpath); 691 ivars->xd_type = strdup(type, M_XENBUS); 692 ivars->xd_state = XenbusStateInitialising; 693 694 error = XENBUSB_GET_OTHEREND_NODE(dev, ivars); 695 if (error) { 696 printf("xenbus_update_device: %s no otherend id\n", 697 devpath); 698 goto out; 699 } 700 701 statepath = malloc(ivars->xd_otherend_path_len 702 + strlen("/state") + 1, M_XENBUS, M_WAITOK); 703 sprintf(statepath, "%s/state", ivars->xd_otherend_path); 704 ivars->xd_otherend_watch.node = statepath; 705 ivars->xd_otherend_watch.callback = xenbusb_otherend_watch_cb; 706 ivars->xd_otherend_watch.callback_data = (uintptr_t)ivars; 707 708 ivars->xd_local_watch.node = ivars->xd_node; 709 ivars->xd_local_watch.callback = xenbusb_local_watch_cb; 710 ivars->xd_local_watch.callback_data = (uintptr_t)ivars; 711 712 mtx_lock(&xbs->xbs_lock); 713 xbs->xbs_connecting_children++; 714 mtx_unlock(&xbs->xbs_lock); 715 716 child = device_add_child(dev, NULL, -1); 717 ivars->xd_dev = child; 718 device_set_ivars(child, ivars); 719 } 720 721 out: 722 sbuf_delete(devpath_sbuf); 723 if (error != 0) 724 xenbusb_free_child_ivars(ivars); 725 726 return (error); 727 } 728 729 int 730 xenbusb_attach(device_t dev, char *bus_node, u_int id_components) 731 { 732 struct xenbusb_softc *xbs; 733 734 xbs = device_get_softc(dev); 735 mtx_init(&xbs->xbs_lock, "xenbusb softc lock", NULL, MTX_DEF); 736 xbs->xbs_node = bus_node; 737 xbs->xbs_id_components = id_components; 738 xbs->xbs_dev = dev; 739 740 /* 741 * Since XenBus busses are attached to the XenStore, and 742 * the XenStore does not probe children until after interrupt 743 * services are available, this config hook is used solely 744 * to ensure that the remainder of the boot process (e.g. 745 * mount root) is deferred until child devices are adequately 746 * probed. We unblock the boot process as soon as the 747 * connecting child count in our softc goes to 0. 748 */ 749 xbs->xbs_attach_ch.ich_func = xenbusb_nop_confighook_cb; 750 xbs->xbs_attach_ch.ich_arg = dev; 751 config_intrhook_establish(&xbs->xbs_attach_ch); 752 xbs->xbs_flags |= XBS_ATTACH_CH_ACTIVE; 753 xbs->xbs_connecting_children = 1; 754 755 /* 756 * The subtree for this bus type may not yet exist 757 * causing initial enumeration to fail. We still 758 * want to return success from our attach though 759 * so that we are ready to handle devices for this 760 * bus when they are dynamically attached to us 761 * by a Xen management action. 762 */ 763 (void)xenbusb_enumerate_bus(xbs); 764 xenbusb_probe_children(dev); 765 766 xbs->xbs_device_watch.node = bus_node; 767 xbs->xbs_device_watch.callback = xenbusb_devices_changed; 768 xbs->xbs_device_watch.callback_data = (uintptr_t)xbs; 769 770 TASK_INIT(&xbs->xbs_probe_children, 0, xenbusb_probe_children_cb, dev); 771 772 xs_register_watch(&xbs->xbs_device_watch); 773 774 xenbusb_release_confighook(xbs); 775 776 return (0); 777 } 778 779 int 780 xenbusb_resume(device_t dev) 781 { 782 device_t *kids; 783 struct xenbus_device_ivars *ivars; 784 int i, count, error; 785 char *statepath; 786 787 /* 788 * We must re-examine each device and find the new path for 789 * its backend. 790 */ 791 if (device_get_children(dev, &kids, &count) == 0) { 792 for (i = 0; i < count; i++) { 793 if (device_get_state(kids[i]) == DS_NOTPRESENT) 794 continue; 795 796 ivars = device_get_ivars(kids[i]); 797 798 xs_unregister_watch(&ivars->xd_otherend_watch); 799 xenbus_set_state(kids[i], XenbusStateInitialising); 800 801 /* 802 * Find the new backend details and 803 * re-register our watch. 804 */ 805 error = XENBUSB_GET_OTHEREND_NODE(dev, ivars); 806 if (error) 807 return (error); 808 809 statepath = malloc(ivars->xd_otherend_path_len 810 + strlen("/state") + 1, M_XENBUS, M_WAITOK); 811 sprintf(statepath, "%s/state", ivars->xd_otherend_path); 812 813 free(ivars->xd_otherend_watch.node, M_XENBUS); 814 ivars->xd_otherend_watch.node = statepath; 815 816 DEVICE_RESUME(kids[i]); 817 818 xs_register_watch(&ivars->xd_otherend_watch); 819 #if 0 820 /* 821 * Can't do this yet since we are running in 822 * the xenwatch thread and if we sleep here, 823 * we will stop delivering watch notifications 824 * and the device will never come back online. 825 */ 826 sx_xlock(&ivars->xd_lock); 827 while (ivars->xd_state != XenbusStateClosed 828 && ivars->xd_state != XenbusStateConnected) 829 sx_sleep(&ivars->xd_state, &ivars->xd_lock, 830 0, "xdresume", 0); 831 sx_xunlock(&ivars->xd_lock); 832 #endif 833 } 834 free(kids, M_TEMP); 835 } 836 837 return (0); 838 } 839 840 int 841 xenbusb_print_child(device_t dev, device_t child) 842 { 843 struct xenbus_device_ivars *ivars = device_get_ivars(child); 844 int retval = 0; 845 846 retval += bus_print_child_header(dev, child); 847 retval += printf(" at %s", ivars->xd_node); 848 retval += bus_print_child_footer(dev, child); 849 850 return (retval); 851 } 852 853 int 854 xenbusb_read_ivar(device_t dev, device_t child, int index, uintptr_t *result) 855 { 856 struct xenbus_device_ivars *ivars = device_get_ivars(child); 857 858 switch (index) { 859 case XENBUS_IVAR_NODE: 860 *result = (uintptr_t) ivars->xd_node; 861 return (0); 862 863 case XENBUS_IVAR_TYPE: 864 *result = (uintptr_t) ivars->xd_type; 865 return (0); 866 867 case XENBUS_IVAR_STATE: 868 *result = (uintptr_t) ivars->xd_state; 869 return (0); 870 871 case XENBUS_IVAR_OTHEREND_ID: 872 *result = (uintptr_t) ivars->xd_otherend_id; 873 return (0); 874 875 case XENBUS_IVAR_OTHEREND_PATH: 876 *result = (uintptr_t) ivars->xd_otherend_path; 877 return (0); 878 } 879 880 return (ENOENT); 881 } 882 883 int 884 xenbusb_write_ivar(device_t dev, device_t child, int index, uintptr_t value) 885 { 886 struct xenbus_device_ivars *ivars = device_get_ivars(child); 887 enum xenbus_state newstate; 888 int currstate; 889 890 switch (index) { 891 case XENBUS_IVAR_STATE: 892 { 893 int error; 894 895 newstate = (enum xenbus_state)value; 896 sx_xlock(&ivars->xd_lock); 897 if (ivars->xd_state == newstate) { 898 error = 0; 899 goto out; 900 } 901 902 error = xs_scanf(XST_NIL, ivars->xd_node, "state", 903 NULL, "%d", &currstate); 904 if (error) 905 goto out; 906 907 do { 908 error = xs_printf(XST_NIL, ivars->xd_node, "state", 909 "%d", newstate); 910 } while (error == EAGAIN); 911 if (error) { 912 /* 913 * Avoid looping through xenbus_dev_fatal() 914 * which calls xenbus_write_ivar to set the 915 * state to closing. 916 */ 917 if (newstate != XenbusStateClosing) 918 xenbus_dev_fatal(dev, error, 919 "writing new state"); 920 goto out; 921 } 922 ivars->xd_state = newstate; 923 924 if ((ivars->xd_flags & XDF_CONNECTING) != 0 925 && (newstate == XenbusStateClosed 926 || newstate == XenbusStateConnected)) { 927 struct xenbusb_softc *xbs; 928 929 ivars->xd_flags &= ~XDF_CONNECTING; 930 xbs = device_get_softc(dev); 931 xenbusb_release_confighook(xbs); 932 } 933 934 wakeup(&ivars->xd_state); 935 out: 936 sx_xunlock(&ivars->xd_lock); 937 return (error); 938 } 939 940 case XENBUS_IVAR_NODE: 941 case XENBUS_IVAR_TYPE: 942 case XENBUS_IVAR_OTHEREND_ID: 943 case XENBUS_IVAR_OTHEREND_PATH: 944 /* 945 * These variables are read-only. 946 */ 947 return (EINVAL); 948 } 949 950 return (ENOENT); 951 } 952 953 void 954 xenbusb_otherend_changed(device_t bus, device_t child, enum xenbus_state state) 955 { 956 XENBUS_OTHEREND_CHANGED(child, state); 957 } 958 959 void 960 xenbusb_localend_changed(device_t bus, device_t child, const char *path) 961 { 962 963 if (strcmp(path, "/state") != 0) { 964 struct xenbus_device_ivars *ivars; 965 966 ivars = device_get_ivars(child); 967 sx_xlock(&ivars->xd_lock); 968 ivars->xd_state = xenbus_read_driver_state(ivars->xd_node); 969 sx_xunlock(&ivars->xd_lock); 970 } 971 XENBUS_LOCALEND_CHANGED(child, path); 972 }
Cache object: d6cb9c01dc56961ae3a60c180826539b
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