release/src-rt-6.x.4708/linux/linux-2.6.36/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 <xen/platform_pci.h>
  60 #include <xen/hvm.h>
  61
  62 #include "xenbus_comms.h"
  63 #include "xenbus_probe.h"
  64
  65
  66 int xen_store_evtchn;
  67 EXPORT_SYMBOL(xen_store_evtchn);
  68
  69 struct xenstore_domain_interface *xen_store_interface;
  70 static unsigned long xen_store_mfn;
  71
  72 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
  73
  74 static void wait_for_devices(struct xenbus_driver *xendrv);
  75
  76 static int xenbus_probe_frontend(const char *type, const char *name);
  77
  78 static void xenbus_dev_shutdown(struct device *_dev);
  79
  80 static int xenbus_dev_suspend(struct device *dev, pm_message_t state);
  81 static int xenbus_dev_resume(struct device *dev);
  82
  83 /* If something in array of ids matches this device, return it. */
  84 static const struct xenbus_device_id *
  85 match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
  86 {
  87         for (; *arr->devicetype != '\0'; arr++) {
  88                 if (!strcmp(arr->devicetype, dev->devicetype))
  89                         return arr;
  90         }
  91         return NULL;
  92 }
  93
  94 int xenbus_match(struct device *_dev, struct device_driver *_drv)
  95 {
  96         struct xenbus_driver *drv = to_xenbus_driver(_drv);
  97
  98         if (!drv->ids)
  99                 return 0;
 100
 101         return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
 102 }
 103
 104 static int xenbus_uevent(struct device *_dev, struct kobj_uevent_env *env)
 105 {
 106         struct xenbus_device *dev = to_xenbus_device(_dev);
 107
 108         if (add_uevent_var(env, "MODALIAS=xen:%s", dev->devicetype))
 109                 return -ENOMEM;
 110
 111         return 0;
 112 }
 113
 114 /* device/<type>/<id> => <type>-<id> */
 115 static int frontend_bus_id(char bus_id[XEN_BUS_ID_SIZE], const char *nodename)
 116 {
 117         nodename = strchr(nodename, '/');
 118         if (!nodename || strlen(nodename + 1) >= XEN_BUS_ID_SIZE) {
 119                 printk(KERN_WARNING "XENBUS: bad frontend %s\n", nodename);
 120                 return -EINVAL;
 121         }
 122
 123         strlcpy(bus_id, nodename + 1, XEN_BUS_ID_SIZE);
 124         if (!strchr(bus_id, '/')) {
 125                 printk(KERN_WARNING "XENBUS: bus_id %s no slash\n", bus_id);
 126                 return -EINVAL;
 127         }
 128         *strchr(bus_id, '/') = '-';
 129         return 0;
 130 }
 131
 132
 133 static void free_otherend_details(struct xenbus_device *dev)
 134 {
 135         kfree(dev->otherend);
 136         dev->otherend = NULL;
 137 }
 138
 139
 140 static void free_otherend_watch(struct xenbus_device *dev)
 141 {
 142         if (dev->otherend_watch.node) {
 143                 unregister_xenbus_watch(&dev->otherend_watch);
 144                 kfree(dev->otherend_watch.node);
 145                 dev->otherend_watch.node = NULL;
 146         }
 147 }
 148
 149
 150 int read_otherend_details(struct xenbus_device *xendev,
 151                                  char *id_node, char *path_node)
 152 {
 153         int err = xenbus_gather(XBT_NIL, xendev->nodename,
 154                                 id_node, "%i", &xendev->otherend_id,
 155                                 path_node, NULL, &xendev->otherend,
 156                                 NULL);
 157         if (err) {
 158                 xenbus_dev_fatal(xendev, err,
 159                                  "reading other end details from %s",
 160                                  xendev->nodename);
 161                 return err;
 162         }
 163         if (strlen(xendev->otherend) == 0 ||
 164             !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
 165                 xenbus_dev_fatal(xendev, -ENOENT,
 166                                  "unable to read other end from %s.  "
 167                                  "missing or inaccessible.",
 168                                  xendev->nodename);
 169                 free_otherend_details(xendev);
 170                 return -ENOENT;
 171         }
 172
 173         return 0;
 174 }
 175
 176
 177 static int read_backend_details(struct xenbus_device *xendev)
 178 {
 179         return read_otherend_details(xendev, "backend-id", "backend");
 180 }
 181
 182 static struct device_attribute xenbus_dev_attrs[] = {
 183         __ATTR_NULL
 184 };
 185
 186 /* Bus type for frontend drivers. */
 187 static struct xen_bus_type xenbus_frontend = {
 188         .root = "device",
 189         .levels = 2,            /* device/type/<id> */
 190         .get_bus_id = frontend_bus_id,
 191         .probe = xenbus_probe_frontend,
 192         .bus = {
 193                 .name      = "xen",
 194                 .match     = xenbus_match,
 195                 .uevent    = xenbus_uevent,
 196                 .probe     = xenbus_dev_probe,
 197                 .remove    = xenbus_dev_remove,
 198                 .shutdown  = xenbus_dev_shutdown,
 199                 .dev_attrs = xenbus_dev_attrs,
 200
 201                 .suspend   = xenbus_dev_suspend,
 202                 .resume    = xenbus_dev_resume,
 203         },
 204 };
 205
 206 static void otherend_changed(struct xenbus_watch *watch,
 207                              const char **vec, unsigned int len)
 208 {
 209         struct xenbus_device *dev =
 210                 container_of(watch, struct xenbus_device, otherend_watch);
 211         struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
 212         enum xenbus_state state;
 213
 214         /* Protect us against watches firing on old details when the otherend
 215            details change, say immediately after a resume. */
 216         if (!dev->otherend ||
 217             strncmp(dev->otherend, vec[XS_WATCH_PATH],
 218                     strlen(dev->otherend))) {
 219                 dev_dbg(&dev->dev, "Ignoring watch at %s\n",
 220                         vec[XS_WATCH_PATH]);
 221                 return;
 222         }
 223
 224         state = xenbus_read_driver_state(dev->otherend);
 225
 226         dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
 227                 state, xenbus_strstate(state), dev->otherend_watch.node,
 228                 vec[XS_WATCH_PATH]);
 229
 230         /*
 231          * Ignore xenbus transitions during shutdown. This prevents us doing
 232          * work that can fail e.g., when the rootfs is gone.
 233          */
 234         if (system_state > SYSTEM_RUNNING) {
 235                 struct xen_bus_type *bus = bus;
 236                 bus = container_of(dev->dev.bus, struct xen_bus_type, bus);
 237                 /* If we're frontend, drive the state machine to Closed. */
 238                 /* This should cause the backend to release our resources. */
 239                 if ((bus == &xenbus_frontend) && (state == XenbusStateClosing))
 240                         xenbus_frontend_closed(dev);
 241                 return;
 242         }
 243
 244         if (drv->otherend_changed)
 245                 drv->otherend_changed(dev, state);
 246 }
 247
 248
 249 static int talk_to_otherend(struct xenbus_device *dev)
 250 {
 251         struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
 252
 253         free_otherend_watch(dev);
 254         free_otherend_details(dev);
 255
 256         return drv->read_otherend_details(dev);
 257 }
 258
 259
 260 static int watch_otherend(struct xenbus_device *dev)
 261 {
 262         return xenbus_watch_pathfmt(dev, &dev->otherend_watch, otherend_changed,
 263                                     "%s/%s", dev->otherend, "state");
 264 }
 265
 266
 267 int xenbus_dev_probe(struct device *_dev)
 268 {
 269         struct xenbus_device *dev = to_xenbus_device(_dev);
 270         struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
 271         const struct xenbus_device_id *id;
 272         int err;
 273
 274         DPRINTK("%s", dev->nodename);
 275
 276         if (!drv->probe) {
 277                 err = -ENODEV;
 278                 goto fail;
 279         }
 280
 281         id = match_device(drv->ids, dev);
 282         if (!id) {
 283                 err = -ENODEV;
 284                 goto fail;
 285         }
 286
 287         err = talk_to_otherend(dev);
 288         if (err) {
 289                 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
 290                          dev->nodename);
 291                 return err;
 292         }
 293
 294         err = drv->probe(dev, id);
 295         if (err)
 296                 goto fail;
 297
 298         err = watch_otherend(dev);
 299         if (err) {
 300                 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
 301                        dev->nodename);
 302                 return err;
 303         }
 304
 305         return 0;
 306 fail:
 307         xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
 308         xenbus_switch_state(dev, XenbusStateClosed);
 309         return -ENODEV;
 310 }
 311
 312 int xenbus_dev_remove(struct device *_dev)
 313 {
 314         struct xenbus_device *dev = to_xenbus_device(_dev);
 315         struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
 316
 317         DPRINTK("%s", dev->nodename);
 318
 319         free_otherend_watch(dev);
 320         free_otherend_details(dev);
 321
 322         if (drv->remove)
 323                 drv->remove(dev);
 324
 325         xenbus_switch_state(dev, XenbusStateClosed);
 326         return 0;
 327 }
 328
 329 static void xenbus_dev_shutdown(struct device *_dev)
 330 {
 331         struct xenbus_device *dev = to_xenbus_device(_dev);
 332         unsigned long timeout = 5*HZ;
 333
 334         DPRINTK("%s", dev->nodename);
 335
 336         get_device(&dev->dev);
 337         if (dev->state != XenbusStateConnected) {
 338                 printk(KERN_INFO "%s: %s: %s != Connected, skipping\n", __func__,
 339                        dev->nodename, xenbus_strstate(dev->state));
 340                 goto out;
 341         }
 342         xenbus_switch_state(dev, XenbusStateClosing);
 343         timeout = wait_for_completion_timeout(&dev->down, timeout);
 344         if (!timeout)
 345                 printk(KERN_INFO "%s: %s timeout closing device\n",
 346                        __func__, dev->nodename);
 347  out:
 348         put_device(&dev->dev);
 349 }
 350
 351 int xenbus_register_driver_common(struct xenbus_driver *drv,
 352                                   struct xen_bus_type *bus,
 353                                   struct module *owner,
 354                                   const char *mod_name)
 355 {
 356         drv->driver.name = drv->name;
 357         drv->driver.bus = &bus->bus;
 358         drv->driver.owner = owner;
 359         drv->driver.mod_name = mod_name;
 360
 361         return driver_register(&drv->driver);
 362 }
 363
 364 int __xenbus_register_frontend(struct xenbus_driver *drv,
 365                                struct module *owner, const char *mod_name)
 366 {
 367         int ret;
 368
 369         drv->read_otherend_details = read_backend_details;
 370
 371         ret = xenbus_register_driver_common(drv, &xenbus_frontend,
 372                                             owner, mod_name);
 373         if (ret)
 374                 return ret;
 375
 376         /* If this driver is loaded as a module wait for devices to attach. */
 377         wait_for_devices(drv);
 378
 379         return 0;
 380 }
 381 EXPORT_SYMBOL_GPL(__xenbus_register_frontend);
 382
 383 void xenbus_unregister_driver(struct xenbus_driver *drv)
 384 {
 385         driver_unregister(&drv->driver);
 386 }
 387 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
 388
 389 struct xb_find_info
 390 {
 391         struct xenbus_device *dev;
 392         const char *nodename;
 393 };
 394
 395 static int cmp_dev(struct device *dev, void *data)
 396 {
 397         struct xenbus_device *xendev = to_xenbus_device(dev);
 398         struct xb_find_info *info = data;
 399
 400         if (!strcmp(xendev->nodename, info->nodename)) {
 401                 info->dev = xendev;
 402                 get_device(dev);
 403                 return 1;
 404         }
 405         return 0;
 406 }
 407
 408 struct xenbus_device *xenbus_device_find(const char *nodename,
 409                                          struct bus_type *bus)
 410 {
 411         struct xb_find_info info = { .dev = NULL, .nodename = nodename };
 412
 413         bus_for_each_dev(bus, NULL, &info, cmp_dev);
 414         return info.dev;
 415 }
 416
 417 static int cleanup_dev(struct device *dev, void *data)
 418 {
 419         struct xenbus_device *xendev = to_xenbus_device(dev);
 420         struct xb_find_info *info = data;
 421         int len = strlen(info->nodename);
 422
 423         DPRINTK("%s", info->nodename);
 424
 425         /* Match the info->nodename path, or any subdirectory of that path. */
 426         if (strncmp(xendev->nodename, info->nodename, len))
 427                 return 0;
 428
 429         /* If the node name is longer, ensure it really is a subdirectory. */
 430         if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
 431                 return 0;
 432
 433         info->dev = xendev;
 434         get_device(dev);
 435         return 1;
 436 }
 437
 438 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
 439 {
 440         struct xb_find_info info = { .nodename = path };
 441
 442         do {
 443                 info.dev = NULL;
 444                 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
 445                 if (info.dev) {
 446                         device_unregister(&info.dev->dev);
 447                         put_device(&info.dev->dev);
 448                 }
 449         } while (info.dev);
 450 }
 451
 452 static void xenbus_dev_release(struct device *dev)
 453 {
 454         if (dev)
 455                 kfree(to_xenbus_device(dev));
 456 }
 457
 458 static ssize_t xendev_show_nodename(struct device *dev,
 459                                     struct device_attribute *attr, char *buf)
 460 {
 461         return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
 462 }
 463 static DEVICE_ATTR(nodename, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_nodename, NULL);
 464
 465 static ssize_t xendev_show_devtype(struct device *dev,
 466                                    struct device_attribute *attr, char *buf)
 467 {
 468         return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
 469 }
 470 static DEVICE_ATTR(devtype, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_devtype, NULL);
 471
 472 static ssize_t xendev_show_modalias(struct device *dev,
 473                                     struct device_attribute *attr, char *buf)
 474 {
 475         return sprintf(buf, "xen:%s\n", to_xenbus_device(dev)->devicetype);
 476 }
 477 static DEVICE_ATTR(modalias, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_modalias, NULL);
 478
 479 int xenbus_probe_node(struct xen_bus_type *bus,
 480                       const char *type,
 481                       const char *nodename)
 482 {
 483         char devname[XEN_BUS_ID_SIZE];
 484         int err;
 485         struct xenbus_device *xendev;
 486         size_t stringlen;
 487         char *tmpstring;
 488
 489         enum xenbus_state state = xenbus_read_driver_state(nodename);
 490
 491         if (state != XenbusStateInitialising) {
 492                 /* Device is not new, so ignore it.  This can happen if a
 493                    device is going away after switching to Closed.  */
 494                 return 0;
 495         }
 496
 497         stringlen = strlen(nodename) + 1 + strlen(type) + 1;
 498         xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
 499         if (!xendev)
 500                 return -ENOMEM;
 501
 502         xendev->state = XenbusStateInitialising;
 503
 504         /* Copy the strings into the extra space. */
 505
 506         tmpstring = (char *)(xendev + 1);
 507         strcpy(tmpstring, nodename);
 508         xendev->nodename = tmpstring;
 509
 510         tmpstring += strlen(tmpstring) + 1;
 511         strcpy(tmpstring, type);
 512         xendev->devicetype = tmpstring;
 513         init_completion(&xendev->down);
 514
 515         xendev->dev.bus = &bus->bus;
 516         xendev->dev.release = xenbus_dev_release;
 517
 518         err = bus->get_bus_id(devname, xendev->nodename);
 519         if (err)
 520                 goto fail;
 521
 522         dev_set_name(&xendev->dev, devname);
 523
 524         /* Register with generic device framework. */
 525         err = device_register(&xendev->dev);
 526         if (err)
 527                 goto fail;
 528
 529         err = device_create_file(&xendev->dev, &dev_attr_nodename);
 530         if (err)
 531                 goto fail_unregister;
 532
 533         err = device_create_file(&xendev->dev, &dev_attr_devtype);
 534         if (err)
 535                 goto fail_remove_nodename;
 536
 537         err = device_create_file(&xendev->dev, &dev_attr_modalias);
 538         if (err)
 539                 goto fail_remove_devtype;
 540
 541         return 0;
 542 fail_remove_devtype:
 543         device_remove_file(&xendev->dev, &dev_attr_devtype);
 544 fail_remove_nodename:
 545         device_remove_file(&xendev->dev, &dev_attr_nodename);
 546 fail_unregister:
 547         device_unregister(&xendev->dev);
 548 fail:
 549         kfree(xendev);
 550         return err;
 551 }
 552
 553 /* device/<typename>/<name> */
 554 static int xenbus_probe_frontend(const char *type, const char *name)
 555 {
 556         char *nodename;
 557         int err;
 558
 559         nodename = kasprintf(GFP_KERNEL, "%s/%s/%s",
 560                              xenbus_frontend.root, type, name);
 561         if (!nodename)
 562                 return -ENOMEM;
 563
 564         DPRINTK("%s", nodename);
 565
 566         err = xenbus_probe_node(&xenbus_frontend, type, nodename);
 567         kfree(nodename);
 568         return err;
 569 }
 570
 571 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
 572 {
 573         int err = 0;
 574         char **dir;
 575         unsigned int dir_n = 0;
 576         int i;
 577
 578         dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
 579         if (IS_ERR(dir))
 580                 return PTR_ERR(dir);
 581
 582         for (i = 0; i < dir_n; i++) {
 583                 err = bus->probe(type, dir[i]);
 584                 if (err)
 585                         break;
 586         }
 587         kfree(dir);
 588         return err;
 589 }
 590
 591 int xenbus_probe_devices(struct xen_bus_type *bus)
 592 {
 593         int err = 0;
 594         char **dir;
 595         unsigned int i, dir_n;
 596
 597         dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
 598         if (IS_ERR(dir))
 599                 return PTR_ERR(dir);
 600
 601         for (i = 0; i < dir_n; i++) {
 602                 err = xenbus_probe_device_type(bus, dir[i]);
 603                 if (err)
 604                         break;
 605         }
 606         kfree(dir);
 607         return err;
 608 }
 609
 610 static unsigned int char_count(const char *str, char c)
 611 {
 612         unsigned int i, ret = 0;
 613
 614         for (i = 0; str[i]; i++)
 615                 if (str[i] == c)
 616                         ret++;
 617         return ret;
 618 }
 619
 620 static int strsep_len(const char *str, char c, unsigned int len)
 621 {
 622         unsigned int i;
 623
 624         for (i = 0; str[i]; i++)
 625                 if (str[i] == c) {
 626                         if (len == 0)
 627                                 return i;
 628                         len--;
 629                 }
 630         return (len == 0) ? i : -ERANGE;
 631 }
 632
 633 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
 634 {
 635         int exists, rootlen;
 636         struct xenbus_device *dev;
 637         char type[XEN_BUS_ID_SIZE];
 638         const char *p, *root;
 639
 640         if (char_count(node, '/') < 2)
 641                 return;
 642
 643         exists = xenbus_exists(XBT_NIL, node, "");
 644         if (!exists) {
 645                 xenbus_cleanup_devices(node, &bus->bus);
 646                 return;
 647         }
 648
 649         /* backend/<type>/... or device/<type>/... */
 650         p = strchr(node, '/') + 1;
 651         snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
 652         type[XEN_BUS_ID_SIZE-1] = '\0';
 653
 654         rootlen = strsep_len(node, '/', bus->levels);
 655         if (rootlen < 0)
 656                 return;
 657         root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
 658         if (!root)
 659                 return;
 660
 661         dev = xenbus_device_find(root, &bus->bus);
 662         if (!dev)
 663                 xenbus_probe_node(bus, type, root);
 664         else
 665                 put_device(&dev->dev);
 666
 667         kfree(root);
 668 }
 669 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
 670
 671 static void frontend_changed(struct xenbus_watch *watch,
 672                              const char **vec, unsigned int len)
 673 {
 674         DPRINTK("");
 675
 676         xenbus_dev_changed(vec[XS_WATCH_PATH], &xenbus_frontend);
 677 }
 678
 679 /* We watch for devices appearing and vanishing. */
 680 static struct xenbus_watch fe_watch = {
 681         .node = "device",
 682         .callback = frontend_changed,
 683 };
 684
 685 static int xenbus_dev_suspend(struct device *dev, pm_message_t state)
 686 {
 687         int err = 0;
 688         struct xenbus_driver *drv;
 689         struct xenbus_device *xdev;
 690
 691         DPRINTK("");
 692
 693         if (dev->driver == NULL)
 694                 return 0;
 695         drv = to_xenbus_driver(dev->driver);
 696         xdev = container_of(dev, struct xenbus_device, dev);
 697         if (drv->suspend)
 698                 err = drv->suspend(xdev, state);
 699         if (err)
 700                 printk(KERN_WARNING
 701                        "xenbus: suspend %s failed: %i\n", dev_name(dev), err);
 702         return 0;
 703 }
 704
 705 static int xenbus_dev_resume(struct device *dev)
 706 {
 707         int err;
 708         struct xenbus_driver *drv;
 709         struct xenbus_device *xdev;
 710
 711         DPRINTK("");
 712
 713         if (dev->driver == NULL)
 714                 return 0;
 715
 716         drv = to_xenbus_driver(dev->driver);
 717         xdev = container_of(dev, struct xenbus_device, dev);
 718
 719         err = talk_to_otherend(xdev);
 720         if (err) {
 721                 printk(KERN_WARNING
 722                        "xenbus: resume (talk_to_otherend) %s failed: %i\n",
 723                        dev_name(dev), err);
 724                 return err;
 725         }
 726
 727         xdev->state = XenbusStateInitialising;
 728
 729         if (drv->resume) {
 730                 err = drv->resume(xdev);
 731                 if (err) {
 732                         printk(KERN_WARNING
 733                                "xenbus: resume %s failed: %i\n",
 734                                dev_name(dev), err);
 735                         return err;
 736                 }
 737         }
 738
 739         err = watch_otherend(xdev);
 740         if (err) {
 741                 printk(KERN_WARNING
 742                        "xenbus_probe: resume (watch_otherend) %s failed: "
 743                        "%d.\n", dev_name(dev), err);
 744                 return err;
 745         }
 746
 747         return 0;
 748 }
 749
 750 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
 751 int xenstored_ready = 0;
 752
 753
 754 int register_xenstore_notifier(struct notifier_block *nb)
 755 {
 756         int ret = 0;
 757
 758         if (xenstored_ready > 0)
 759                 ret = nb->notifier_call(nb, 0, NULL);
 760         else
 761                 blocking_notifier_chain_register(&xenstore_chain, nb);
 762
 763         return ret;
 764 }
 765 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
 766
 767 void unregister_xenstore_notifier(struct notifier_block *nb)
 768 {
 769         blocking_notifier_chain_unregister(&xenstore_chain, nb);
 770 }
 771 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
 772
 773 void xenbus_probe(struct work_struct *unused)
 774 {
 775         xenstored_ready = 1;
 776
 777         /* Enumerate devices in xenstore and watch for changes. */
 778         xenbus_probe_devices(&xenbus_frontend);
 779         register_xenbus_watch(&fe_watch);
 780         xenbus_backend_probe_and_watch();
 781
 782         /* Notify others that xenstore is up */
 783         blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
 784 }
 785 EXPORT_SYMBOL_GPL(xenbus_probe);
 786
 787 static int __init xenbus_probe_initcall(void)
 788 {
 789         if (!xen_domain())
 790                 return -ENODEV;
 791
 792         if (xen_initial_domain() || xen_hvm_domain())
 793                 return 0;
 794
 795         xenbus_probe(NULL);
 796         return 0;
 797 }
 798
 799 device_initcall(xenbus_probe_initcall);
 800
 801 static int __init xenbus_init(void)
 802 {
 803         int err = 0;
 804
 805         DPRINTK("");
 806
 807         err = -ENODEV;
 808         if (!xen_domain())
 809                 goto out_error;
 810
 811         /* Register ourselves with the kernel bus subsystem */
 812         err = bus_register(&xenbus_frontend.bus);
 813         if (err)
 814                 goto out_error;
 815
 816         err = xenbus_backend_bus_register();
 817         if (err)
 818                 goto out_unreg_front;
 819
 820         /*
 821          * Domain0 doesn't have a store_evtchn or store_mfn yet.
 822          */
 823         if (xen_initial_domain()) {
 824                 /* dom0 not yet supported */
 825         } else {
 826                 if (xen_hvm_domain()) {
 827                         uint64_t v = 0;
 828                         err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
 829                         if (err)
 830                                 goto out_error;
 831                         xen_store_evtchn = (int)v;
 832                         err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
 833                         if (err)
 834                                 goto out_error;
 835                         xen_store_mfn = (unsigned long)v;
 836                         xen_store_interface = ioremap(xen_store_mfn << PAGE_SHIFT, PAGE_SIZE);
 837                 } else {
 838                         xen_store_evtchn = xen_start_info->store_evtchn;
 839                         xen_store_mfn = xen_start_info->store_mfn;
 840                         xen_store_interface = mfn_to_virt(xen_store_mfn);
 841                         xenstored_ready = 1;
 842                 }
 843         }
 844
 845         /* Initialize the interface to xenstore. */
 846         err = xs_init();
 847         if (err) {
 848                 printk(KERN_WARNING
 849                        "XENBUS: Error initializing xenstore comms: %i\n", err);
 850                 goto out_unreg_back;
 851         }
 852
 853 #ifdef CONFIG_XEN_COMPAT_XENFS
 854         /*
 855          * Create xenfs mountpoint in /proc for compatibility with
 856          * utilities that expect to find "xenbus" under "/proc/xen".
 857          */
 858         proc_mkdir("xen", NULL);
 859 #endif
 860
 861         return 0;
 862
 863   out_unreg_back:
 864         xenbus_backend_bus_unregister();
 865
 866   out_unreg_front:
 867         bus_unregister(&xenbus_frontend.bus);
 868
 869   out_error:
 870         return err;
 871 }
 872
 873 postcore_initcall(xenbus_init);
 874
 875 MODULE_LICENSE("GPL");
 876
 877 static int is_device_connecting(struct device *dev, void *data)
 878 {
 879         struct xenbus_device *xendev = to_xenbus_device(dev);
 880         struct device_driver *drv = data;
 881         struct xenbus_driver *xendrv;
 882
 883         /*
 884          * A device with no driver will never connect. We care only about
 885          * devices which should currently be in the process of connecting.
 886          */
 887         if (!dev->driver)
 888                 return 0;
 889
 890         /* Is this search limited to a particular driver? */
 891         if (drv && (dev->driver != drv))
 892                 return 0;
 893
 894         xendrv = to_xenbus_driver(dev->driver);
 895         return (xendev->state < XenbusStateConnected ||
 896                 (xendev->state == XenbusStateConnected &&
 897                  xendrv->is_ready && !xendrv->is_ready(xendev)));
 898 }
 899
 900 static int exists_connecting_device(struct device_driver *drv)
 901 {
 902         return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
 903                                 is_device_connecting);
 904 }
 905
 906 static int print_device_status(struct device *dev, void *data)
 907 {
 908         struct xenbus_device *xendev = to_xenbus_device(dev);
 909         struct device_driver *drv = data;
 910
 911         /* Is this operation limited to a particular driver? */
 912         if (drv && (dev->driver != drv))
 913                 return 0;
 914
 915         if (!dev->driver) {
 916                 /* Information only: is this too noisy? */
 917                 printk(KERN_INFO "XENBUS: Device with no driver: %s\n",
 918                        xendev->nodename);
 919         } else if (xendev->state < XenbusStateConnected) {
 920                 enum xenbus_state rstate = XenbusStateUnknown;
 921                 if (xendev->otherend)
 922                         rstate = xenbus_read_driver_state(xendev->otherend);
 923                 printk(KERN_WARNING "XENBUS: Timeout connecting "
 924                        "to device: %s (local state %d, remote state %d)\n",
 925                        xendev->nodename, xendev->state, rstate);
 926         }
 927
 928         return 0;
 929 }
 930
 931 /* We only wait for device setup after most initcalls have run. */
 932 static int ready_to_wait_for_devices;
 933
 934 /*
 935  * On a 5-minute timeout, wait for all devices currently configured.  We need
 936  * to do this to guarantee that the filesystems and / or network devices
 937  * needed for boot are available, before we can allow the boot to proceed.
 938  *
 939  * This needs to be on a late_initcall, to happen after the frontend device
 940  * drivers have been initialised, but before the root fs is mounted.
 941  *
 942  * A possible improvement here would be to have the tools add a per-device
 943  * flag to the store entry, indicating whether it is needed at boot time.
 944  * This would allow people who knew what they were doing to accelerate their
 945  * boot slightly, but of course needs tools or manual intervention to set up
 946  * those flags correctly.
 947  */
 948 static void wait_for_devices(struct xenbus_driver *xendrv)
 949 {
 950         unsigned long start = jiffies;
 951         struct device_driver *drv = xendrv ? &xendrv->driver : NULL;
 952         unsigned int seconds_waited = 0;
 953
 954         if (!ready_to_wait_for_devices || !xen_domain())
 955                 return;
 956
 957         while (exists_connecting_device(drv)) {
 958                 if (time_after(jiffies, start + (seconds_waited+5)*HZ)) {
 959                         if (!seconds_waited)
 960                                 printk(KERN_WARNING "XENBUS: Waiting for "
 961                                        "devices to initialise: ");
 962                         seconds_waited += 5;
 963                         printk("%us...", 300 - seconds_waited);
 964                         if (seconds_waited == 300)
 965                                 break;
 966                 }
 967
 968                 schedule_timeout_interruptible(HZ/10);
 969         }
 970
 971         if (seconds_waited)
 972                 printk("\n");
 973
 974         bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
 975                          print_device_status);
 976 }
 977
 978 #ifndef MODULE
 979 static int __init boot_wait_for_devices(void)
 980 {
 981         if (xen_hvm_domain() && !xen_platform_pci_unplug)
 982                 return -ENODEV;
 983
 984         ready_to_wait_for_devices = 1;
 985         wait_for_devices(NULL);
 986         return 0;
 987 }
 988
 989 late_initcall(boot_wait_for_devices);
 990 #endif