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