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/notifier.h>
  44 #include <linux/kthread.h>
  45 #include <linux/mutex.h>
  46 #include <linux/io.h>
  47
  48 #include <asm/page.h>
  49 #include <asm/pgtable.h>
  50 #include <asm/xen/hypervisor.h>
  51 #include <xen/xenbus.h>
  52 #include <xen/events.h>
  53 #include <xen/page.h>
  54
  55 #include "xenbus_comms.h"
  56 #include "xenbus_probe.h"
  57
  58 int xen_store_evtchn;
  59 struct xenstore_domain_interface *xen_store_interface;
  60 static unsigned long xen_store_mfn;
  61
  62 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
  63
  64 static void wait_for_devices(struct xenbus_driver *xendrv);
  65
  66 static int xenbus_probe_frontend(const char *type, const char *name);
  67
  68 static void xenbus_dev_shutdown(struct device *_dev);
  69
  70 /* If something in array of ids matches this device, return it. */
  71 static const struct xenbus_device_id *
  72 match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
  73 {
  74         for (; *arr->devicetype != '\0'; arr++) {
  75                 if (!strcmp(arr->devicetype, dev->devicetype))
  76                         return arr;
  77         }
  78         return NULL;
  79 }
  80
  81 int xenbus_match(struct device *_dev, struct device_driver *_drv)
  82 {
  83         struct xenbus_driver *drv = to_xenbus_driver(_drv);
  84
  85         if (!drv->ids)
  86                 return 0;
  87
  88         return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
  89 }
  90
  91 static int xenbus_uevent(struct device *_dev, struct kobj_uevent_env *env)
  92 {
  93         struct xenbus_device *dev = to_xenbus_device(_dev);
  94
  95         if (add_uevent_var(env, "MODALIAS=xen:%s", dev->devicetype))
  96                 return -ENOMEM;
  97
  98         return 0;
  99 }
 100
 101 /* device/<type>/<id> => <type>-<id> */
 102 static int frontend_bus_id(char bus_id[BUS_ID_SIZE], const char *nodename)
 103 {
 104         nodename = strchr(nodename, '/');
 105         if (!nodename || strlen(nodename + 1) >= BUS_ID_SIZE) {
 106                 printk(KERN_WARNING "XENBUS: bad frontend %s\n", nodename);
 107                 return -EINVAL;
 108         }
 109
 110         strlcpy(bus_id, nodename + 1, BUS_ID_SIZE);
 111         if (!strchr(bus_id, '/')) {
 112                 printk(KERN_WARNING "XENBUS: bus_id %s no slash\n", bus_id);
 113                 return -EINVAL;
 114         }
 115         *strchr(bus_id, '/') = '-';
 116         return 0;
 117 }
 118
 119
 120 static void free_otherend_details(struct xenbus_device *dev)
 121 {
 122         kfree(dev->otherend);
 123         dev->otherend = NULL;
 124 }
 125
 126
 127 static void free_otherend_watch(struct xenbus_device *dev)
 128 {
 129         if (dev->otherend_watch.node) {
 130                 unregister_xenbus_watch(&dev->otherend_watch);
 131                 kfree(dev->otherend_watch.node);
 132                 dev->otherend_watch.node = NULL;
 133         }
 134 }
 135
 136
 137 int read_otherend_details(struct xenbus_device *xendev,
 138                                  char *id_node, char *path_node)
 139 {
 140         int err = xenbus_gather(XBT_NIL, xendev->nodename,
 141                                 id_node, "%i", &xendev->otherend_id,
 142                                 path_node, NULL, &xendev->otherend,
 143                                 NULL);
 144         if (err) {
 145                 xenbus_dev_fatal(xendev, err,
 146                                  "reading other end details from %s",
 147                                  xendev->nodename);
 148                 return err;
 149         }
 150         if (strlen(xendev->otherend) == 0 ||
 151             !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
 152                 xenbus_dev_fatal(xendev, -ENOENT,
 153                                  "unable to read other end from %s.  "
 154                                  "missing or inaccessible.",
 155                                  xendev->nodename);
 156                 free_otherend_details(xendev);
 157                 return -ENOENT;
 158         }
 159
 160         return 0;
 161 }
 162
 163
 164 static int read_backend_details(struct xenbus_device *xendev)
 165 {
 166         return read_otherend_details(xendev, "backend-id", "backend");
 167 }
 168
 169
 170 /* Bus type for frontend drivers. */
 171 static struct xen_bus_type xenbus_frontend = {
 172         .root = "device",
 173         .levels = 2,            /* device/type/<id> */
 174         .get_bus_id = frontend_bus_id,
 175         .probe = xenbus_probe_frontend,
 176         .bus = {
 177                 .name     = "xen",
 178                 .match    = xenbus_match,
 179                 .uevent   = xenbus_uevent,
 180                 .probe    = xenbus_dev_probe,
 181                 .remove   = xenbus_dev_remove,
 182                 .shutdown = xenbus_dev_shutdown,
 183         },
 184 };
 185
 186 static void otherend_changed(struct xenbus_watch *watch,
 187                              const char **vec, unsigned int len)
 188 {
 189         struct xenbus_device *dev =
 190                 container_of(watch, struct xenbus_device, otherend_watch);
 191         struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
 192         enum xenbus_state state;
 193
 194         /* Protect us against watches firing on old details when the otherend
 195            details change, say immediately after a resume. */
 196         if (!dev->otherend ||
 197             strncmp(dev->otherend, vec[XS_WATCH_PATH],
 198                     strlen(dev->otherend))) {
 199                 dev_dbg(&dev->dev, "Ignoring watch at %s\n",
 200                         vec[XS_WATCH_PATH]);
 201                 return;
 202         }
 203
 204         state = xenbus_read_driver_state(dev->otherend);
 205
 206         dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
 207                 state, xenbus_strstate(state), dev->otherend_watch.node,
 208                 vec[XS_WATCH_PATH]);
 209
 210         /*
 211          * Ignore xenbus transitions during shutdown. This prevents us doing
 212          * work that can fail e.g., when the rootfs is gone.
 213          */
 214         if (system_state > SYSTEM_RUNNING) {
 215                 struct xen_bus_type *bus = bus;
 216                 bus = container_of(dev->dev.bus, struct xen_bus_type, bus);
 217                 /* If we're frontend, drive the state machine to Closed. */
 218                 /* This should cause the backend to release our resources. */
 219                 if ((bus == &xenbus_frontend) && (state == XenbusStateClosing))
 220                         xenbus_frontend_closed(dev);
 221                 return;
 222         }
 223
 224         if (drv->otherend_changed)
 225                 drv->otherend_changed(dev, state);
 226 }
 227
 228
 229 static int talk_to_otherend(struct xenbus_device *dev)
 230 {
 231         struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
 232
 233         free_otherend_watch(dev);
 234         free_otherend_details(dev);
 235
 236         return drv->read_otherend_details(dev);
 237 }
 238
 239
 240 static int watch_otherend(struct xenbus_device *dev)
 241 {
 242         return xenbus_watch_pathfmt(dev, &dev->otherend_watch, otherend_changed,
 243                                     "%s/%s", dev->otherend, "state");
 244 }
 245
 246
 247 int xenbus_dev_probe(struct device *_dev)
 248 {
 249         struct xenbus_device *dev = to_xenbus_device(_dev);
 250         struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
 251         const struct xenbus_device_id *id;
 252         int err;
 253
 254         DPRINTK("%s", dev->nodename);
 255
 256         if (!drv->probe) {
 257                 err = -ENODEV;
 258                 goto fail;
 259         }
 260
 261         id = match_device(drv->ids, dev);
 262         if (!id) {
 263                 err = -ENODEV;
 264                 goto fail;
 265         }
 266
 267         err = talk_to_otherend(dev);
 268         if (err) {
 269                 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
 270                          dev->nodename);
 271                 return err;
 272         }
 273
 274         err = drv->probe(dev, id);
 275         if (err)
 276                 goto fail;
 277
 278         err = watch_otherend(dev);
 279         if (err) {
 280                 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
 281                        dev->nodename);
 282                 return err;
 283         }
 284
 285         return 0;
 286 fail:
 287         xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
 288         xenbus_switch_state(dev, XenbusStateClosed);
 289         return -ENODEV;
 290 }
 291
 292 int xenbus_dev_remove(struct device *_dev)
 293 {
 294         struct xenbus_device *dev = to_xenbus_device(_dev);
 295         struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
 296
 297         DPRINTK("%s", dev->nodename);
 298
 299         free_otherend_watch(dev);
 300         free_otherend_details(dev);
 301
 302         if (drv->remove)
 303                 drv->remove(dev);
 304
 305         xenbus_switch_state(dev, XenbusStateClosed);
 306         return 0;
 307 }
 308
 309 static void xenbus_dev_shutdown(struct device *_dev)
 310 {
 311         struct xenbus_device *dev = to_xenbus_device(_dev);
 312         unsigned long timeout = 5*HZ;
 313
 314         DPRINTK("%s", dev->nodename);
 315
 316         get_device(&dev->dev);
 317         if (dev->state != XenbusStateConnected) {
 318                 printk(KERN_INFO "%s: %s: %s != Connected, skipping\n", __func__,
 319                        dev->nodename, xenbus_strstate(dev->state));
 320                 goto out;
 321         }
 322         xenbus_switch_state(dev, XenbusStateClosing);
 323         timeout = wait_for_completion_timeout(&dev->down, timeout);
 324         if (!timeout)
 325                 printk(KERN_INFO "%s: %s timeout closing device\n",
 326                        __func__, dev->nodename);
 327  out:
 328         put_device(&dev->dev);
 329 }
 330
 331 int xenbus_register_driver_common(struct xenbus_driver *drv,
 332                                   struct xen_bus_type *bus,
 333                                   struct module *owner,
 334                                   const char *mod_name)
 335 {
 336         drv->driver.name = drv->name;
 337         drv->driver.bus = &bus->bus;
 338         drv->driver.owner = owner;
 339         drv->driver.mod_name = mod_name;
 340
 341         return driver_register(&drv->driver);
 342 }
 343
 344 int __xenbus_register_frontend(struct xenbus_driver *drv,
 345                                struct module *owner, const char *mod_name)
 346 {
 347         int ret;
 348
 349         drv->read_otherend_details = read_backend_details;
 350
 351         ret = xenbus_register_driver_common(drv, &xenbus_frontend,
 352                                             owner, mod_name);
 353         if (ret)
 354                 return ret;
 355
 356         /* If this driver is loaded as a module wait for devices to attach. */
 357         wait_for_devices(drv);
 358
 359         return 0;
 360 }
 361 EXPORT_SYMBOL_GPL(__xenbus_register_frontend);
 362
 363 void xenbus_unregister_driver(struct xenbus_driver *drv)
 364 {
 365         driver_unregister(&drv->driver);
 366 }
 367 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
 368
 369 struct xb_find_info
 370 {
 371         struct xenbus_device *dev;
 372         const char *nodename;
 373 };
 374
 375 static int cmp_dev(struct device *dev, void *data)
 376 {
 377         struct xenbus_device *xendev = to_xenbus_device(dev);
 378         struct xb_find_info *info = data;
 379
 380         if (!strcmp(xendev->nodename, info->nodename)) {
 381                 info->dev = xendev;
 382                 get_device(dev);
 383                 return 1;
 384         }
 385         return 0;
 386 }
 387
 388 struct xenbus_device *xenbus_device_find(const char *nodename,
 389                                          struct bus_type *bus)
 390 {
 391         struct xb_find_info info = { .dev = NULL, .nodename = nodename };
 392
 393         bus_for_each_dev(bus, NULL, &info, cmp_dev);
 394         return info.dev;
 395 }
 396
 397 static int cleanup_dev(struct device *dev, void *data)
 398 {
 399         struct xenbus_device *xendev = to_xenbus_device(dev);
 400         struct xb_find_info *info = data;
 401         int len = strlen(info->nodename);
 402
 403         DPRINTK("%s", info->nodename);
 404
 405         /* Match the info->nodename path, or any subdirectory of that path. */
 406         if (strncmp(xendev->nodename, info->nodename, len))
 407                 return 0;
 408
 409         /* If the node name is longer, ensure it really is a subdirectory. */
 410         if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
 411                 return 0;
 412
 413         info->dev = xendev;
 414         get_device(dev);
 415         return 1;
 416 }
 417
 418 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
 419 {
 420         struct xb_find_info info = { .nodename = path };
 421
 422         do {
 423                 info.dev = NULL;
 424                 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
 425                 if (info.dev) {
 426                         device_unregister(&info.dev->dev);
 427                         put_device(&info.dev->dev);
 428                 }
 429         } while (info.dev);
 430 }
 431
 432 static void xenbus_dev_release(struct device *dev)
 433 {
 434         if (dev)
 435                 kfree(to_xenbus_device(dev));
 436 }
 437
 438 static ssize_t xendev_show_nodename(struct device *dev,
 439                                     struct device_attribute *attr, char *buf)
 440 {
 441         return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
 442 }
 443 DEVICE_ATTR(nodename, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_nodename, NULL);
 444
 445 static ssize_t xendev_show_devtype(struct device *dev,
 446                                    struct device_attribute *attr, char *buf)
 447 {
 448         return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
 449 }
 450 DEVICE_ATTR(devtype, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_devtype, NULL);
 451
 452 static ssize_t xendev_show_modalias(struct device *dev,
 453                                     struct device_attribute *attr, char *buf)
 454 {
 455         return sprintf(buf, "xen:%s\n", to_xenbus_device(dev)->devicetype);
 456 }
 457 DEVICE_ATTR(modalias, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_modalias, NULL);
 458
 459 int xenbus_probe_node(struct xen_bus_type *bus,
 460                       const char *type,
 461                       const char *nodename)
 462 {
 463         int err;
 464         struct xenbus_device *xendev;
 465         size_t stringlen;
 466         char *tmpstring;
 467
 468         enum xenbus_state state = xenbus_read_driver_state(nodename);
 469
 470         if (state != XenbusStateInitialising) {
 471                 /* Device is not new, so ignore it.  This can happen if a
 472                    device is going away after switching to Closed.  */
 473                 return 0;
 474         }
 475
 476         stringlen = strlen(nodename) + 1 + strlen(type) + 1;
 477         xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
 478         if (!xendev)
 479                 return -ENOMEM;
 480
 481         xendev->state = XenbusStateInitialising;
 482
 483         /* Copy the strings into the extra space. */
 484
 485         tmpstring = (char *)(xendev + 1);
 486         strcpy(tmpstring, nodename);
 487         xendev->nodename = tmpstring;
 488
 489         tmpstring += strlen(tmpstring) + 1;
 490         strcpy(tmpstring, type);
 491         xendev->devicetype = tmpstring;
 492         init_completion(&xendev->down);
 493
 494         xendev->dev.bus = &bus->bus;
 495         xendev->dev.release = xenbus_dev_release;
 496
 497         err = bus->get_bus_id(xendev->dev.bus_id, xendev->nodename);
 498         if (err)
 499                 goto fail;
 500
 501         /* Register with generic device framework. */
 502         err = device_register(&xendev->dev);
 503         if (err)
 504                 goto fail;
 505
 506         err = device_create_file(&xendev->dev, &dev_attr_nodename);
 507         if (err)
 508                 goto fail_unregister;
 509
 510         err = device_create_file(&xendev->dev, &dev_attr_devtype);
 511         if (err)
 512                 goto fail_remove_nodename;
 513
 514         err = device_create_file(&xendev->dev, &dev_attr_modalias);
 515         if (err)
 516                 goto fail_remove_devtype;
 517
 518         return 0;
 519 fail_remove_devtype:
 520         device_remove_file(&xendev->dev, &dev_attr_devtype);
 521 fail_remove_nodename:
 522         device_remove_file(&xendev->dev, &dev_attr_nodename);
 523 fail_unregister:
 524         device_unregister(&xendev->dev);
 525 fail:
 526         kfree(xendev);
 527         return err;
 528 }
 529
 530 /* device/<typename>/<name> */
 531 static int xenbus_probe_frontend(const char *type, const char *name)
 532 {
 533         char *nodename;
 534         int err;
 535
 536         nodename = kasprintf(GFP_KERNEL, "%s/%s/%s",
 537                              xenbus_frontend.root, type, name);
 538         if (!nodename)
 539                 return -ENOMEM;
 540
 541         DPRINTK("%s", nodename);
 542
 543         err = xenbus_probe_node(&xenbus_frontend, type, nodename);
 544         kfree(nodename);
 545         return err;
 546 }
 547
 548 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
 549 {
 550         int err = 0;
 551         char **dir;
 552         unsigned int dir_n = 0;
 553         int i;
 554
 555         dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
 556         if (IS_ERR(dir))
 557                 return PTR_ERR(dir);
 558
 559         for (i = 0; i < dir_n; i++) {
 560                 err = bus->probe(type, dir[i]);
 561                 if (err)
 562                         break;
 563         }
 564         kfree(dir);
 565         return err;
 566 }
 567
 568 int xenbus_probe_devices(struct xen_bus_type *bus)
 569 {
 570         int err = 0;
 571         char **dir;
 572         unsigned int i, dir_n;
 573
 574         dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
 575         if (IS_ERR(dir))
 576                 return PTR_ERR(dir);
 577
 578         for (i = 0; i < dir_n; i++) {
 579                 err = xenbus_probe_device_type(bus, dir[i]);
 580                 if (err)
 581                         break;
 582         }
 583         kfree(dir);
 584         return err;
 585 }
 586
 587 static unsigned int char_count(const char *str, char c)
 588 {
 589         unsigned int i, ret = 0;
 590
 591         for (i = 0; str[i]; i++)
 592                 if (str[i] == c)
 593                         ret++;
 594         return ret;
 595 }
 596
 597 static int strsep_len(const char *str, char c, unsigned int len)
 598 {
 599         unsigned int i;
 600
 601         for (i = 0; str[i]; i++)
 602                 if (str[i] == c) {
 603                         if (len == 0)
 604                                 return i;
 605                         len--;
 606                 }
 607         return (len == 0) ? i : -ERANGE;
 608 }
 609
 610 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
 611 {
 612         int exists, rootlen;
 613         struct xenbus_device *dev;
 614         char type[BUS_ID_SIZE];
 615         const char *p, *root;
 616
 617         if (char_count(node, '/') < 2)
 618                 return;
 619
 620         exists = xenbus_exists(XBT_NIL, node, "");
 621         if (!exists) {
 622                 xenbus_cleanup_devices(node, &bus->bus);
 623                 return;
 624         }
 625
 626         /* backend/<type>/... or device/<type>/... */
 627         p = strchr(node, '/') + 1;
 628         snprintf(type, BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
 629         type[BUS_ID_SIZE-1] = '\0';
 630
 631         rootlen = strsep_len(node, '/', bus->levels);
 632         if (rootlen < 0)
 633                 return;
 634         root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
 635         if (!root)
 636                 return;
 637
 638         dev = xenbus_device_find(root, &bus->bus);
 639         if (!dev)
 640                 xenbus_probe_node(bus, type, root);
 641         else
 642                 put_device(&dev->dev);
 643
 644         kfree(root);
 645 }
 646
 647 static void frontend_changed(struct xenbus_watch *watch,
 648                              const char **vec, unsigned int len)
 649 {
 650         DPRINTK("");
 651
 652         xenbus_dev_changed(vec[XS_WATCH_PATH], &xenbus_frontend);
 653 }
 654
 655 /* We watch for devices appearing and vanishing. */
 656 static struct xenbus_watch fe_watch = {
 657         .node = "device",
 658         .callback = frontend_changed,
 659 };
 660
 661 static int suspend_dev(struct device *dev, void *data)
 662 {
 663         int err = 0;
 664         struct xenbus_driver *drv;
 665         struct xenbus_device *xdev;
 666
 667         DPRINTK("");
 668
 669         if (dev->driver == NULL)
 670                 return 0;
 671         drv = to_xenbus_driver(dev->driver);
 672         xdev = container_of(dev, struct xenbus_device, dev);
 673         if (drv->suspend)
 674                 err = drv->suspend(xdev);
 675         if (err)
 676                 printk(KERN_WARNING
 677                        "xenbus: suspend %s failed: %i\n", dev->bus_id, err);
 678         return 0;
 679 }
 680
 681 static int suspend_cancel_dev(struct device *dev, void *data)
 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_cancel)
 694                 err = drv->suspend_cancel(xdev);
 695         if (err)
 696                 printk(KERN_WARNING
 697                        "xenbus: suspend_cancel %s failed: %i\n",
 698                        dev->bus_id, err);
 699         return 0;
 700 }
 701
 702 static int resume_dev(struct device *dev, void *data)
 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->bus_id, 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->bus_id, 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->bus_id, err);
 741                 return err;
 742         }
 743
 744         return 0;
 745 }
 746
 747 void xenbus_suspend(void)
 748 {
 749         DPRINTK("");
 750
 751         bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, suspend_dev);
 752         xenbus_backend_suspend(suspend_dev);
 753         xs_suspend();
 754 }
 755 EXPORT_SYMBOL_GPL(xenbus_suspend);
 756
 757 void xenbus_resume(void)
 758 {
 759         xb_init_comms();
 760         xs_resume();
 761         bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, resume_dev);
 762         xenbus_backend_resume(resume_dev);
 763 }
 764 EXPORT_SYMBOL_GPL(xenbus_resume);
 765
 766 void xenbus_suspend_cancel(void)
 767 {
 768         xs_suspend_cancel();
 769         bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, suspend_cancel_dev);
 770         xenbus_backend_resume(suspend_cancel_dev);
 771 }
 772 EXPORT_SYMBOL_GPL(xenbus_suspend_cancel);
 773
 774 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
 775 int xenstored_ready = 0;
 776
 777
 778 int register_xenstore_notifier(struct notifier_block *nb)
 779 {
 780         int ret = 0;
 781
 782         if (xenstored_ready > 0)
 783                 ret = nb->notifier_call(nb, 0, NULL);
 784         else
 785                 blocking_notifier_chain_register(&xenstore_chain, nb);
 786
 787         return ret;
 788 }
 789 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
 790
 791 void unregister_xenstore_notifier(struct notifier_block *nb)
 792 {
 793         blocking_notifier_chain_unregister(&xenstore_chain, nb);
 794 }
 795 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
 796
 797 void xenbus_probe(struct work_struct *unused)
 798 {
 799         BUG_ON((xenstored_ready <= 0));
 800
 801         /* Enumerate devices in xenstore and watch for changes. */
 802         xenbus_probe_devices(&xenbus_frontend);
 803         register_xenbus_watch(&fe_watch);
 804         xenbus_backend_probe_and_watch();
 805
 806         /* Notify others that xenstore is up */
 807         blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
 808 }
 809
 810 static int __init xenbus_probe_init(void)
 811 {
 812         int err = 0;
 813
 814         DPRINTK("");
 815
 816         err = -ENODEV;
 817         if (!is_running_on_xen())
 818                 goto out_error;
 819
 820         /* Register ourselves with the kernel bus subsystem */
 821         err = bus_register(&xenbus_frontend.bus);
 822         if (err)
 823                 goto out_error;
 824
 825         err = xenbus_backend_bus_register();
 826         if (err)
 827                 goto out_unreg_front;
 828
 829         /*
 830          * Domain0 doesn't have a store_evtchn or store_mfn yet.
 831          */
 832         if (is_initial_xendomain()) {
 833                 /* dom0 not yet supported */
 834         } else {
 835                 xenstored_ready = 1;
 836                 xen_store_evtchn = xen_start_info->store_evtchn;
 837                 xen_store_mfn = xen_start_info->store_mfn;
 838         }
 839         xen_store_interface = mfn_to_virt(xen_store_mfn);
 840
 841         /* Initialize the interface to xenstore. */
 842         err = xs_init();
 843         if (err) {
 844                 printk(KERN_WARNING
 845                        "XENBUS: Error initializing xenstore comms: %i\n", err);
 846                 goto out_unreg_back;
 847         }
 848
 849         if (!is_initial_xendomain())
 850                 xenbus_probe(NULL);
 851
 852         return 0;
 853
 854   out_unreg_back:
 855         xenbus_backend_bus_unregister();
 856
 857   out_unreg_front:
 858         bus_unregister(&xenbus_frontend.bus);
 859
 860   out_error:
 861         return err;
 862 }
 863
 864 postcore_initcall(xenbus_probe_init);
 865
 866 MODULE_LICENSE("GPL");
 867
 868 static int is_disconnected_device(struct device *dev, void *data)
 869 {
 870         struct xenbus_device *xendev = to_xenbus_device(dev);
 871         struct device_driver *drv = data;
 872         struct xenbus_driver *xendrv;
 873
 874         /*
 875          * A device with no driver will never connect. We care only about
 876          * devices which should currently be in the process of connecting.
 877          */
 878         if (!dev->driver)
 879                 return 0;
 880
 881         /* Is this search limited to a particular driver? */
 882         if (drv && (dev->driver != drv))
 883                 return 0;
 884
 885         xendrv = to_xenbus_driver(dev->driver);
 886         return (xendev->state != XenbusStateConnected ||
 887                 (xendrv->is_ready && !xendrv->is_ready(xendev)));
 888 }
 889
 890 static int exists_disconnected_device(struct device_driver *drv)
 891 {
 892         return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
 893                                 is_disconnected_device);
 894 }
 895
 896 static int print_device_status(struct device *dev, void *data)
 897 {
 898         struct xenbus_device *xendev = to_xenbus_device(dev);
 899         struct device_driver *drv = data;
 900
 901         /* Is this operation limited to a particular driver? */
 902         if (drv && (dev->driver != drv))
 903                 return 0;
 904
 905         if (!dev->driver) {
 906                 /* Information only: is this too noisy? */
 907                 printk(KERN_INFO "XENBUS: Device with no driver: %s\n",
 908                        xendev->nodename);
 909         } else if (xendev->state != XenbusStateConnected) {
 910                 printk(KERN_WARNING "XENBUS: Timeout connecting "
 911                        "to device: %s (state %d)\n",
 912                        xendev->nodename, xendev->state);
 913         }
 914
 915         return 0;
 916 }
 917
 918 /* We only wait for device setup after most initcalls have run. */
 919 static int ready_to_wait_for_devices;
 920
 921 /*
 922  * On a 10 second timeout, wait for all devices currently configured.  We need
 923  * to do this to guarantee that the filesystems and / or network devices
 924  * needed for boot are available, before we can allow the boot to proceed.
 925  *
 926  * This needs to be on a late_initcall, to happen after the frontend device
 927  * drivers have been initialised, but before the root fs is mounted.
 928  *
 929  * A possible improvement here would be to have the tools add a per-device
 930  * flag to the store entry, indicating whether it is needed at boot time.
 931  * This would allow people who knew what they were doing to accelerate their
 932  * boot slightly, but of course needs tools or manual intervention to set up
 933  * those flags correctly.
 934  */
 935 static void wait_for_devices(struct xenbus_driver *xendrv)
 936 {
 937         unsigned long timeout = jiffies + 10*HZ;
 938         struct device_driver *drv = xendrv ? &xendrv->driver : NULL;
 939
 940         if (!ready_to_wait_for_devices || !is_running_on_xen())
 941                 return;
 942
 943         while (exists_disconnected_device(drv)) {
 944                 if (time_after(jiffies, timeout))
 945                         break;
 946                 schedule_timeout_interruptible(HZ/10);
 947         }
 948
 949         bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
 950                          print_device_status);
 951 }
 952
 953 #ifndef MODULE
 954 static int __init boot_wait_for_devices(void)
 955 {
 956         ready_to_wait_for_devices = 1;
 957         wait_for_devices(NULL);
 958         return 0;
 959 }
 960
 961 late_initcall(boot_wait_for_devices);
 962 #endif