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