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