drivers/xen/xenbus/xenbus_probe.c

   1 /******************************************************************************
   2  * Talks to Xen Store to figure out what devices we have.
   3  *
   4  * Copyright (C) 2005 Rusty Russell, IBM Corporation
   5  * Copyright (C) 2005 Mike Wray, Hewlett-Packard
   6  * Copyright (C) 2005, 2006 XenSource Ltd
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License version 2
  10  * as published by the Free Software Foundation; or, when distributed
  11  * separately from the Linux kernel or incorporated into other
  12  * software packages, subject to the following license:
  13  *
  14  * Permission is hereby granted, free of charge, to any person obtaining a copy
  15  * of this source file (the "Software"), to deal in the Software without
  16  * restriction, including without limitation the rights to use, copy, modify,
  17  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  18  * and to permit persons to whom the Software is furnished to do so, subject to
  19  * the following conditions:
  20  *
  21  * The above copyright notice and this permission notice shall be included in
  22  * all copies or substantial portions of the Software.
  23  *
  24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  25  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  26  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  27  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  28  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  29  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  30  * IN THE SOFTWARE.
  31  */
  32
  33 #define DPRINTK(fmt, args...)                           \
  34         pr_debug("xenbus_probe (%s:%d) " fmt ".\n",     \
  35                  __func__, __LINE__, ##args)
  36
  37 #include <linux/kernel.h>
  38 #include <linux/err.h>
  39 #include <linux/string.h>
  40 #include <linux/ctype.h>
  41 #include <linux/fcntl.h>
  42 #include <linux/mm.h>
  43 #include <linux/proc_fs.h>
  44 #include <linux/notifier.h>
  45 #include <linux/kthread.h>
  46 #include <linux/mutex.h>
  47 #include <linux/io.h>
  48
  49 #include <asm/page.h>
  50 #include <asm/pgtable.h>
  51 #include <asm/xen/hypervisor.h>
  52
  53 #include <xen/xen.h>
  54 #include <xen/xenbus.h>
  55 #include <xen/events.h>
  56 #include <xen/page.h>
  57
  58 #include "xenbus_comms.h"
  59 #include "xenbus_probe.h"
  60
  61
  62 int xen_store_evtchn;
  63 EXPORT_SYMBOL(xen_store_evtchn);
  64
  65 struct xenstore_domain_interface *xen_store_interface;
  66 static unsigned long xen_store_mfn;
  67
  68 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
  69
  70 static void wait_for_devices(struct xenbus_driver *xendrv);
  71
  72 static int xenbus_probe_frontend(const char *type, const char *name);
  73
  74 static void xenbus_dev_shutdown(struct device *_dev);
  75
  76 static int xenbus_dev_suspend(struct device *dev, pm_message_t state);
  77 static int xenbus_dev_resume(struct device *dev);
  78
  79 /* If something in array of ids matches this device, return it. */
  80 static const struct xenbus_device_id *
  81 match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
  82 {
  83         for (; *arr->devicetype != '\0'; arr++) {
  84                 if (!strcmp(arr->devicetype, dev->devicetype))
  85                         return arr;
  86         }
  87         return NULL;
  88 }
  89
  90 int xenbus_match(struct device *_dev, struct device_driver *_drv)
  91 {
  92         struct xenbus_driver *drv = to_xenbus_driver(_drv);
  93
  94         if (!drv->ids)
  95                 return 0;
  96
  97         return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
  98 }
  99
 100 static int xenbus_uevent(struct device *_dev, struct kobj_uevent_env *env)
 101 {
 102         struct xenbus_device *dev = to_xenbus_device(_dev);
 103
 104         if (add_uevent_var(env, "MODALIAS=xen:%s", dev->devicetype))
 105                 return -ENOMEM;
 106
 107         return 0;
 108 }
 109
 110 /* device/<type>/<id> => <type>-<id> */
 111 static int frontend_bus_id(char bus_id[XEN_BUS_ID_SIZE], const char *nodename)
 112 {
 113         nodename = strchr(nodename, '/');
 114         if (!nodename || strlen(nodename + 1) >= XEN_BUS_ID_SIZE) {
 115                 printk(KERN_WARNING "XENBUS: bad frontend %s\n", nodename);
 116                 return -EINVAL;
 117         }
 118
 119         strlcpy(bus_id, nodename + 1, XEN_BUS_ID_SIZE);
 120         if (!strchr(bus_id, '/')) {
 121                 printk(KERN_WARNING "XENBUS: bus_id %s no slash\n", bus_id);
 122                 return -EINVAL;
 123         }
 124         *strchr(bus_id, '/') = '-';
 125         return 0;
 126 }
 127
 128
 129 static void free_otherend_details(struct xenbus_device *dev)
 130 {
 131         kfree(dev->otherend);
 132         dev->otherend = NULL;
 133 }
 134
 135
 136 static void free_otherend_watch(struct xenbus_device *dev)
 137 {
 138         if (dev->otherend_watch.node) {
 139                 unregister_xenbus_watch(&dev->otherend_watch);
 140                 kfree(dev->otherend_watch.node);
 141                 dev->otherend_watch.node = NULL;
 142         }
 143 }
 144
 145
 146 int read_otherend_details(struct xenbus_device *xendev,
 147                                  char *id_node, char *path_node)
 148 {
 149         int err = xenbus_gather(XBT_NIL, xendev->nodename,
 150                                 id_node, "%i", &xendev->otherend_id,
 151                                 path_node, NULL, &xendev->otherend,
 152                                 NULL);
 153         if (err) {
 154                 xenbus_dev_fatal(xendev, err,
 155                                  "reading other end details from %s",
 156                                  xendev->nodename);
 157                 return err;
 158         }
 159         if (strlen(xendev->otherend) == 0 ||
 160             !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
 161                 xenbus_dev_fatal(xendev, -ENOENT,
 162                                  "unable to read other end from %s.  "
 163                                  "missing or inaccessible.",
 164                                  xendev->nodename);
 165                 free_otherend_details(xendev);
 166                 return -ENOENT;
 167         }
 168
 169         return 0;
 170 }
 171
 172
 173 static int read_backend_details(struct xenbus_device *xendev)
 174 {
 175         return read_otherend_details(xendev, "backend-id", "backend");
 176 }
 177
 178 static struct device_attribute xenbus_dev_attrs[] = {
 179         __ATTR_NULL
 180 };
 181
 182 /* Bus type for frontend drivers. */
 183 static struct xen_bus_type xenbus_frontend = {
 184         .root = "device",
 185         .levels = 2,            /* device/type/<id> */
 186         .get_bus_id = frontend_bus_id,
 187         .probe = xenbus_probe_frontend,
 188         .bus = {
 189                 .name      = "xen",
 190                 .match     = xenbus_match,
 191                 .uevent    = xenbus_uevent,
 192                 .probe     = xenbus_dev_probe,
 193                 .remove    = xenbus_dev_remove,
 194                 .shutdown  = xenbus_dev_shutdown,
 195                 .dev_attrs = xenbus_dev_attrs,
 196
 197                 .suspend   = xenbus_dev_suspend,
 198                 .resume    = xenbus_dev_resume,
 199         },
 200 };
 201
 202 static void otherend_changed(struct xenbus_watch *watch,
 203                              const char **vec, unsigned int len)
 204 {
 205         struct xenbus_device *dev =
 206                 container_of(watch, struct xenbus_device, otherend_watch);
 207         struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
 208         enum xenbus_state state;
 209
 210         /* Protect us against watches firing on old details when the otherend
 211            details change, say immediately after a resume. */
 212         if (!dev->otherend ||
 213             strncmp(dev->otherend, vec[XS_WATCH_PATH],
 214                     strlen(dev->otherend))) {
 215                 dev_dbg(&dev->dev, "Ignoring watch at %s\n",
 216                         vec[XS_WATCH_PATH]);
 217                 return;
 218         }
 219
 220         state = xenbus_read_driver_state(dev->otherend);
 221
 222         dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
 223                 state, xenbus_strstate(state), dev->otherend_watch.node,
 224                 vec[XS_WATCH_PATH]);
 225
 226         /*
 227          * Ignore xenbus transitions during shutdown. This prevents us doing
 228          * work that can fail e.g., when the rootfs is gone.
 229          */
 230         if (system_state > SYSTEM_RUNNING) {
 231                 struct xen_bus_type *bus = bus;
 232                 bus = container_of(dev->dev.bus, struct xen_bus_type, bus);
 233                 /* If we're frontend, drive the state machine to Closed. */
 234                 /* This should cause the backend to release our resources. */
 235                 if ((bus == &xenbus_frontend) && (state == XenbusStateClosing))
 236                         xenbus_frontend_closed(dev);
 237                 return;
 238         }
 239
 240         if (drv->otherend_changed)
 241                 drv->otherend_changed(dev, state);
 242 }
 243
 244
 245 static int talk_to_otherend(struct xenbus_device *dev)
 246 {
 247         struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
 248
 249         free_otherend_watch(dev);
 250         free_otherend_details(dev);
 251
 252         return drv->read_otherend_details(dev);
 253 }
 254
 255
 256 static int watch_otherend(struct xenbus_device *dev)
 257 {
 258         return xenbus_watch_pathfmt(dev, &dev->otherend_watch, otherend_changed,
 259                                     "%s/%s", dev->otherend, "state");
 260 }
 261
 262
 263 int xenbus_dev_probe(struct device *_dev)
 264 {
 265         struct xenbus_device *dev = to_xenbus_device(_dev);
 266         struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
 267         const struct xenbus_device_id *id;
 268         int err;
 269
 270         DPRINTK("%s", dev->nodename);
 271
 272         if (!drv->probe) {
 273                 err = -ENODEV;
 274                 goto fail;
 275         }
 276
 277         id = match_device(drv->ids, dev);
 278         if (!id) {
 279                 err = -ENODEV;
 280                 goto fail;
 281         }
 282
 283         err = talk_to_otherend(dev);
 284         if (err) {
 285                 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
 286                          dev->nodename);
 287                 return err;
 288         }
 289
 290         err = drv->probe(dev, id);
 291         if (err)
 292                 goto fail;
 293
 294         err = watch_otherend(dev);
 295         if (err) {
 296                 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
 297                        dev->nodename);
 298                 return err;
 299         }
 300
 301         return 0;
 302 fail:
 303         xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
 304         xenbus_switch_state(dev, XenbusStateClosed);
 305         return -ENODEV;
 306 }
 307
 308 int xenbus_dev_remove(struct device *_dev)
 309 {
 310         struct xenbus_device *dev = to_xenbus_device(_dev);
 311         struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
 312
 313         DPRINTK("%s", dev->nodename);
 314
 315         free_otherend_watch(dev);
 316         free_otherend_details(dev);
 317
 318         if (drv->remove)
 319                 drv->remove(dev);
 320
 321         xenbus_switch_state(dev, XenbusStateClosed);
 322         return 0;
 323 }
 324
 325 static void xenbus_dev_shutdown(struct device *_dev)
 326 {
 327         struct xenbus_device *dev = to_xenbus_device(_dev);
 328         unsigned long timeout = 5*HZ;
 329
 330         DPRINTK("%s", dev->nodename);
 331
 332         get_device(&dev->dev);
 333         if (dev->state != XenbusStateConnected) {
 334                 printk(KERN_INFO "%s: %s: %s != Connected, skipping\n", __func__,
 335                        dev->nodename, xenbus_strstate(dev->state));
 336                 goto out;
 337         }
 338         xenbus_switch_state(dev, XenbusStateClosing);
 339         timeout = wait_for_completion_timeout(&dev->down, timeout);
 340         if (!timeout)
 341                 printk(KERN_INFO "%s: %s timeout closing device\n",
 342                        __func__, dev->nodename);
 343  out:
 344         put_device(&dev->dev);
 345 }
 346
 347 int xenbus_register_driver_common(struct xenbus_driver *drv,
 348                                   struct xen_bus_type *bus,
 349                                   struct module *owner,
 350                                   const char *mod_name)
 351 {
 352         drv->driver.name = drv->name;
 353         drv->driver.bus = &bus->bus;
 354         drv->driver.owner = owner;
 355         drv->driver.mod_name = mod_name;
 356
 357         return driver_register(&drv->driver);
 358 }
 359
 360 int __xenbus_register_frontend(struct xenbus_driver *drv,
 361                                struct module *owner, const char *mod_name)
 362 {
 363         int ret;
 364
 365         drv->read_otherend_details = read_backend_details;
 366
 367         ret = xenbus_register_driver_common(drv, &xenbus_frontend,
 368                                             owner, mod_name);
 369         if (ret)
 370                 return ret;
 371
 372         /* If this driver is loaded as a module wait for devices to attach. */
 373         wait_for_devices(drv);
 374
 375         return 0;
 376 }
 377 EXPORT_SYMBOL_GPL(__xenbus_register_frontend);
 378
 379 void xenbus_unregister_driver(struct xenbus_driver *drv)
 380 {
 381         driver_unregister(&drv->driver);
 382 }
 383 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
 384
 385 struct xb_find_info
 386 {
 387         struct xenbus_device *dev;
 388         const char *nodename;
 389 };
 390
 391 static int cmp_dev(struct device *dev, void *data)
 392 {
 393         struct xenbus_device *xendev = to_xenbus_device(dev);
 394         struct xb_find_info *info = data;
 395
 396         if (!strcmp(xendev->nodename, info->nodename)) {
 397                 info->dev = xendev;
 398                 get_device(dev);
 399                 return 1;
 400         }
 401         return 0;
 402 }
 403
 404 struct xenbus_device *xenbus_device_find(const char *nodename,
 405                                          struct bus_type *bus)
 406 {
 407         struct xb_find_info info = { .dev = NULL, .nodename = nodename };
 408
 409         bus_for_each_dev(bus, NULL, &info, cmp_dev);
 410         return info.dev;
 411 }
 412
 413 static int cleanup_dev(struct device *dev, void *data)
 414 {
 415         struct xenbus_device *xendev = to_xenbus_device(dev);
 416         struct xb_find_info *info = data;
 417         int len = strlen(info->nodename);
 418
 419         DPRINTK("%s", info->nodename);
 420
 421         /* Match the info->nodename path, or any subdirectory of that path. */
 422         if (strncmp(xendev->nodename, info->nodename, len))
 423                 return 0;
 424
 425         /* If the node name is longer, ensure it really is a subdirectory. */
 426         if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
 427                 return 0;
 428
 429         info->dev = xendev;
 430         get_device(dev);
 431         return 1;
 432 }
 433
 434 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
 435 {
 436         struct xb_find_info info = { .nodename = path };
 437
 438         do {
 439                 info.dev = NULL;
 440                 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
 441                 if (info.dev) {
 442                         device_unregister(&info.dev->dev);
 443                         put_device(&info.dev->dev);
 444                 }
 445         } while (info.dev);
 446 }
 447
 448 static void xenbus_dev_release(struct device *dev)
 449 {
 450         if (dev)
 451                 kfree(to_xenbus_device(dev));
 452 }
 453
 454 static ssize_t xendev_show_nodename(struct device *dev,
 455                                     struct device_attribute *attr, char *buf)
 456 {
 457         return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
 458 }
 459 static DEVICE_ATTR(nodename, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_nodename, NULL);
 460
 461 static ssize_t xendev_show_devtype(struct device *dev,
 462                                    struct device_attribute *attr, char *buf)
 463 {
 464         return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
 465 }
 466 static DEVICE_ATTR(devtype, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_devtype, NULL);
 467
 468 static ssize_t xendev_show_modalias(struct device *dev,
 469                                     struct device_attribute *attr, char *buf)
 470 {
 471         return sprintf(buf, "xen:%s\n", to_xenbus_device(dev)->devicetype);
 472 }
 473 static DEVICE_ATTR(modalias, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_modalias, NULL);
 474
 475 int xenbus_probe_node(struct xen_bus_type *bus,
 476                       const char *type,
 477                       const char *nodename)
 478 {
 479         char devname[XEN_BUS_ID_SIZE];
 480         int err;
 481         struct xenbus_device *xendev;
 482         size_t stringlen;
 483         char *tmpstring;
 484
 485         enum xenbus_state state = xenbus_read_driver_state(nodename);
 486
 487         if (state != XenbusStateInitialising) {
 488                 /* Device is not new, so ignore it.  This can happen if a
 489                    device is going away after switching to Closed.  */
 490                 return 0;
 491         }
 492
 493         stringlen = strlen(nodename) + 1 + strlen(type) + 1;
 494         xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
 495         if (!xendev)
 496                 return -ENOMEM;
 497
 498         xendev->state = XenbusStateInitialising;
 499
 500         /* Copy the strings into the extra space. */
 501
 502         tmpstring = (char *)(xendev + 1);
 503         strcpy(tmpstring, nodename);
 504         xendev->nodename = tmpstring;
 505
 506         tmpstring += strlen(tmpstring) + 1;
 507         strcpy(tmpstring, type);
 508         xendev->devicetype = tmpstring;
 509         init_completion(&xendev->down);
 510
 511         xendev->dev.bus = &bus->bus;
 512         xendev->dev.release = xenbus_dev_release;
 513
 514         err = bus->get_bus_id(devname, xendev->nodename);
 515         if (err)
 516                 goto fail;
 517
 518         dev_set_name(&xendev->dev, devname);
 519
 520         /* Register with generic device framework. */
 521         err = device_register(&xendev->dev);
 522         if (err)
 523                 goto fail;
 524
 525         err = device_create_file(&xendev->dev, &dev_attr_nodename);
 526         if (err)
 527                 goto fail_unregister;
 528
 529         err = device_create_file(&xendev->dev, &dev_attr_devtype);
 530         if (err)
 531                 goto fail_remove_nodename;
 532
 533         err = device_create_file(&xendev->dev, &dev_attr_modalias);
 534         if (err)
 535                 goto fail_remove_devtype;
 536
 537         return 0;
 538 fail_remove_devtype:
 539         device_remove_file(&xendev->dev, &dev_attr_devtype);
 540 fail_remove_nodename:
 541         device_remove_file(&xendev->dev, &dev_attr_nodename);
 542 fail_unregister:
 543         device_unregister(&xendev->dev);
 544 fail:
 545         kfree(xendev);
 546         return err;
 547 }
 548
 549 /* device/<typename>/<name> */
 550 static int xenbus_probe_frontend(const char *type, const char *name)
 551 {
 552         char *nodename;
 553         int err;
 554
 555         nodename = kasprintf(GFP_KERNEL, "%s/%s/%s",
 556                              xenbus_frontend.root, type, name);
 557         if (!nodename)
 558                 return -ENOMEM;
 559
 560         DPRINTK("%s", nodename);
 561
 562         err = xenbus_probe_node(&xenbus_frontend, type, nodename);
 563         kfree(nodename);
 564         return err;
 565 }
 566
 567 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
 568 {
 569         int err = 0;
 570         char **dir;
 571         unsigned int dir_n = 0;
 572         int i;
 573
 574         dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
 575         if (IS_ERR(dir))
 576                 return PTR_ERR(dir);
 577
 578         for (i = 0; i < dir_n; i++) {
 579                 err = bus->probe(type, dir[i]);
 580                 if (err)
 581                         break;
 582         }
 583         kfree(dir);
 584         return err;
 585 }
 586
 587 int xenbus_probe_devices(struct xen_bus_type *bus)
 588 {
 589         int err = 0;
 590         char **dir;
 591         unsigned int i, dir_n;
 592
 593         dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
 594         if (IS_ERR(dir))
 595                 return PTR_ERR(dir);
 596
 597         for (i = 0; i < dir_n; i++) {
 598                 err = xenbus_probe_device_type(bus, dir[i]);
 599                 if (err)
 600                         break;
 601         }
 602         kfree(dir);
 603         return err;
 604 }
 605
 606 static unsigned int char_count(const char *str, char c)
 607 {
 608         unsigned int i, ret = 0;
 609
 610         for (i = 0; str[i]; i++)
 611                 if (str[i] == c)
 612                         ret++;
 613         return ret;
 614 }
 615
 616 static int strsep_len(const char *str, char c, unsigned int len)
 617 {
 618         unsigned int i;
 619
 620         for (i = 0; str[i]; i++)
 621                 if (str[i] == c) {
 622                         if (len == 0)
 623                                 return i;
 624                         len--;
 625                 }
 626         return (len == 0) ? i : -ERANGE;
 627 }
 628
 629 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
 630 {
 631         int exists, rootlen;
 632         struct xenbus_device *dev;
 633         char type[XEN_BUS_ID_SIZE];
 634         const char *p, *root;
 635
 636         if (char_count(node, '/') < 2)
 637                 return;
 638
 639         exists = xenbus_exists(XBT_NIL, node, "");
 640         if (!exists) {
 641                 xenbus_cleanup_devices(node, &bus->bus);
 642                 return;
 643         }
 644
 645         /* backend/<type>/... or device/<type>/... */
 646         p = strchr(node, '/') + 1;
 647         snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
 648         type[XEN_BUS_ID_SIZE-1] = '\0';
 649
 650         rootlen = strsep_len(node, '/', bus->levels);
 651         if (rootlen < 0)
 652                 return;
 653         root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
 654         if (!root)
 655                 return;
 656
 657         dev = xenbus_device_find(root, &bus->bus);
 658         if (!dev)
 659                 xenbus_probe_node(bus, type, root);
 660         else
 661                 put_device(&dev->dev);
 662
 663         kfree(root);
 664 }
 665 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
 666
 667 static void frontend_changed(struct xenbus_watch *watch,
 668                              const char **vec, unsigned int len)
 669 {
 670         DPRINTK("");
 671
 672         xenbus_dev_changed(vec[XS_WATCH_PATH], &xenbus_frontend);
 673 }
 674
 675 /* We watch for devices appearing and vanishing. */
 676 static struct xenbus_watch fe_watch = {
 677         .node = "device",
 678         .callback = frontend_changed,
 679 };
 680
 681 static int xenbus_dev_suspend(struct device *dev, pm_message_t state)
 682 {
 683         int err = 0;
 684         struct xenbus_driver *drv;
 685         struct xenbus_device *xdev;
 686
 687         DPRINTK("");
 688
 689         if (dev->driver == NULL)
 690                 return 0;
 691         drv = to_xenbus_driver(dev->driver);
 692         xdev = container_of(dev, struct xenbus_device, dev);
 693         if (drv->suspend)
 694                 err = drv->suspend(xdev, state);
 695         if (err)
 696                 printk(KERN_WARNING
 697                        "xenbus: suspend %s failed: %i\n", dev_name(dev), err);
 698         return 0;
 699 }
 700
 701 static int xenbus_dev_resume(struct device *dev)
 702 {
 703         int err;
 704         struct xenbus_driver *drv;
 705         struct xenbus_device *xdev;
 706
 707         DPRINTK("");
 708
 709         if (dev->driver == NULL)
 710                 return 0;
 711
 712         drv = to_xenbus_driver(dev->driver);
 713         xdev = container_of(dev, struct xenbus_device, dev);
 714
 715         err = talk_to_otherend(xdev);
 716         if (err) {
 717                 printk(KERN_WARNING
 718                        "xenbus: resume (talk_to_otherend) %s failed: %i\n",
 719                        dev_name(dev), err);
 720                 return err;
 721         }
 722
 723         xdev->state = XenbusStateInitialising;
 724
 725         if (drv->resume) {
 726                 err = drv->resume(xdev);
 727                 if (err) {
 728                         printk(KERN_WARNING
 729                                "xenbus: resume %s failed: %i\n",
 730                                dev_name(dev), err);
 731                         return err;
 732                 }
 733         }
 734
 735         err = watch_otherend(xdev);
 736         if (err) {
 737                 printk(KERN_WARNING
 738                        "xenbus_probe: resume (watch_otherend) %s failed: "
 739                        "%d.\n", dev_name(dev), err);
 740                 return err;
 741         }
 742
 743         return 0;
 744 }
 745
 746 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
 747 int xenstored_ready = 0;
 748
 749
 750 int register_xenstore_notifier(struct notifier_block *nb)
 751 {
 752         int ret = 0;
 753
 754         if (xenstored_ready > 0)
 755                 ret = nb->notifier_call(nb, 0, NULL);
 756         else
 757                 blocking_notifier_chain_register(&xenstore_chain, nb);
 758
 759         return ret;
 760 }
 761 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
 762
 763 void unregister_xenstore_notifier(struct notifier_block *nb)
 764 {
 765         blocking_notifier_chain_unregister(&xenstore_chain, nb);
 766 }
 767 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
 768
 769 void xenbus_probe(struct work_struct *unused)
 770 {
 771         BUG_ON((xenstored_ready <= 0));
 772
 773         /* Enumerate devices in xenstore and watch for changes. */
 774         xenbus_probe_devices(&xenbus_frontend);
 775         register_xenbus_watch(&fe_watch);
 776         xenbus_backend_probe_and_watch();
 777
 778         /* Notify others that xenstore is up */
 779         blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
 780 }
 781
 782 static int __init xenbus_probe_init(void)
 783 {
 784         int err = 0;
 785
 786         DPRINTK("");
 787
 788         err = -ENODEV;
 789         if (!xen_domain())
 790                 goto out_error;
 791
 792         /* Register ourselves with the kernel bus subsystem */
 793         err = bus_register(&xenbus_frontend.bus);
 794         if (err)
 795                 goto out_error;
 796
 797         err = xenbus_backend_bus_register();
 798         if (err)
 799                 goto out_unreg_front;
 800
 801         /*
 802          * Domain0 doesn't have a store_evtchn or store_mfn yet.
 803          */
 804         if (xen_initial_domain()) {
 805                 /* dom0 not yet supported */
 806         } else {
 807                 xenstored_ready = 1;
 808                 xen_store_evtchn = xen_start_info->store_evtchn;
 809                 xen_store_mfn = xen_start_info->store_mfn;
 810         }
 811         xen_store_interface = mfn_to_virt(xen_store_mfn);
 812
 813         /* Initialize the interface to xenstore. */
 814         err = xs_init();
 815         if (err) {
 816                 printk(KERN_WARNING
 817                        "XENBUS: Error initializing xenstore comms: %i\n", err);
 818                 goto out_unreg_back;
 819         }
 820
 821         if (!xen_initial_domain())
 822                 xenbus_probe(NULL);
 823
 824 #ifdef CONFIG_XEN_COMPAT_XENFS
 825         /*
 826          * Create xenfs mountpoint in /proc for compatibility with
 827          * utilities that expect to find "xenbus" under "/proc/xen".
 828          */
 829         proc_mkdir("xen", NULL);
 830 #endif
 831
 832         return 0;
 833
 834   out_unreg_back:
 835         xenbus_backend_bus_unregister();
 836
 837   out_unreg_front:
 838         bus_unregister(&xenbus_frontend.bus);
 839
 840   out_error:
 841         return err;
 842 }
 843
 844 postcore_initcall(xenbus_probe_init);
 845
 846 MODULE_LICENSE("GPL");
 847
 848 static int is_device_connecting(struct device *dev, void *data)
 849 {
 850         struct xenbus_device *xendev = to_xenbus_device(dev);
 851         struct device_driver *drv = data;
 852         struct xenbus_driver *xendrv;
 853
 854         /*
 855          * A device with no driver will never connect. We care only about
 856          * devices which should currently be in the process of connecting.
 857          */
 858         if (!dev->driver)
 859                 return 0;
 860
 861         /* Is this search limited to a particular driver? */
 862         if (drv && (dev->driver != drv))
 863                 return 0;
 864
 865         xendrv = to_xenbus_driver(dev->driver);
 866         return (xendev->state < XenbusStateConnected ||
 867                 (xendev->state == XenbusStateConnected &&
 868                  xendrv->is_ready && !xendrv->is_ready(xendev)));
 869 }
 870
 871 static int exists_connecting_device(struct device_driver *drv)
 872 {
 873         return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
 874                                 is_device_connecting);
 875 }
 876
 877 static int print_device_status(struct device *dev, void *data)
 878 {
 879         struct xenbus_device *xendev = to_xenbus_device(dev);
 880         struct device_driver *drv = data;
 881
 882         /* Is this operation limited to a particular driver? */
 883         if (drv && (dev->driver != drv))
 884                 return 0;
 885
 886         if (!dev->driver) {
 887                 /* Information only: is this too noisy? */
 888                 printk(KERN_INFO "XENBUS: Device with no driver: %s\n",
 889                        xendev->nodename);
 890         } else if (xendev->state < XenbusStateConnected) {
 891                 enum xenbus_state rstate = XenbusStateUnknown;
 892                 if (xendev->otherend)
 893                         rstate = xenbus_read_driver_state(xendev->otherend);
 894                 printk(KERN_WARNING "XENBUS: Timeout connecting "
 895                        "to device: %s (local state %d, remote state %d)\n",
 896                        xendev->nodename, xendev->state, rstate);
 897         }
 898
 899         return 0;
 900 }
 901
 902 /* We only wait for device setup after most initcalls have run. */
 903 static int ready_to_wait_for_devices;
 904
 905 /*
 906  * On a 5-minute timeout, wait for all devices currently configured.  We need
 907  * to do this to guarantee that the filesystems and / or network devices
 908  * needed for boot are available, before we can allow the boot to proceed.
 909  *
 910  * This needs to be on a late_initcall, to happen after the frontend device
 911  * drivers have been initialised, but before the root fs is mounted.
 912  *
 913  * A possible improvement here would be to have the tools add a per-device
 914  * flag to the store entry, indicating whether it is needed at boot time.
 915  * This would allow people who knew what they were doing to accelerate their
 916  * boot slightly, but of course needs tools or manual intervention to set up
 917  * those flags correctly.
 918  */
 919 static void wait_for_devices(struct xenbus_driver *xendrv)
 920 {
 921         unsigned long start = jiffies;
 922         struct device_driver *drv = xendrv ? &xendrv->driver : NULL;
 923         unsigned int seconds_waited = 0;
 924
 925         if (!ready_to_wait_for_devices || !xen_domain())
 926                 return;
 927
 928         while (exists_connecting_device(drv)) {
 929                 if (time_after(jiffies, start + (seconds_waited+5)*HZ)) {
 930                         if (!seconds_waited)
 931                                 printk(KERN_WARNING "XENBUS: Waiting for "
 932                                        "devices to initialise: ");
 933                         seconds_waited += 5;
 934                         printk("%us...", 300 - seconds_waited);
 935                         if (seconds_waited == 300)
 936                                 break;
 937                 }
 938
 939                 schedule_timeout_interruptible(HZ/10);
 940         }
 941
 942         if (seconds_waited)
 943                 printk("\n");
 944
 945         bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
 946                          print_device_status);
 947 }
 948
 949 #ifndef MODULE
 950 static int __init boot_wait_for_devices(void)
 951 {
 952         ready_to_wait_for_devices = 1;
 953         wait_for_devices(NULL);
 954         return 0;
 955 }
 956
 957 late_initcall(boot_wait_for_devices);
 958 #endif