drivers/hv/vmbus_drv.c

   1 /*
   2  * Copyright (c) 2009, Microsoft Corporation.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  15  * Place - Suite 330, Boston, MA 02111-1307 USA.
  16  *
  17  * Authors:
  18  *   Haiyang Zhang <haiyangz@microsoft.com>
  19  *   Hank Janssen  <hjanssen@microsoft.com>
  20  *   K. Y. Srinivasan <kys@microsoft.com>
  21  *
  22  */
  23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  24
  25 #include <linux/init.h>
  26 #include <linux/module.h>
  27 #include <linux/device.h>
  28 #include <linux/irq.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/sysctl.h>
  31 #include <linux/slab.h>
  32 #include <linux/acpi.h>
  33 #include <acpi/acpi_bus.h>
  34 #include <linux/completion.h>
  35 #include <linux/hyperv.h>
  36 #include <asm/hyperv.h>
  37 #include <asm/hypervisor.h>
  38 #include "hyperv_vmbus.h"
  39
  40
  41 static struct acpi_device  *hv_acpi_dev;
  42
  43 static struct tasklet_struct msg_dpc;
  44 static struct tasklet_struct event_dpc;
  45 static struct completion probe_event;
  46 static int irq;
  47
  48 struct hv_device_info {
  49         u32 chn_id;
  50         u32 chn_state;
  51         uuid_le chn_type;
  52         uuid_le chn_instance;
  53
  54         u32 monitor_id;
  55         u32 server_monitor_pending;
  56         u32 server_monitor_latency;
  57         u32 server_monitor_conn_id;
  58         u32 client_monitor_pending;
  59         u32 client_monitor_latency;
  60         u32 client_monitor_conn_id;
  61
  62         struct hv_dev_port_info inbound;
  63         struct hv_dev_port_info outbound;
  64 };
  65
  66 static int vmbus_exists(void)
  67 {
  68         if (hv_acpi_dev == NULL)
  69                 return -ENODEV;
  70
  71         return 0;
  72 }
  73
  74
  75 static void get_channel_info(struct hv_device *device,
  76                              struct hv_device_info *info)
  77 {
  78         struct vmbus_channel_debug_info debug_info;
  79
  80         if (!device->channel)
  81                 return;
  82
  83         vmbus_get_debug_info(device->channel, &debug_info);
  84
  85         info->chn_id = debug_info.relid;
  86         info->chn_state = debug_info.state;
  87         memcpy(&info->chn_type, &debug_info.interfacetype,
  88                sizeof(uuid_le));
  89         memcpy(&info->chn_instance, &debug_info.interface_instance,
  90                sizeof(uuid_le));
  91
  92         info->monitor_id = debug_info.monitorid;
  93
  94         info->server_monitor_pending = debug_info.servermonitor_pending;
  95         info->server_monitor_latency = debug_info.servermonitor_latency;
  96         info->server_monitor_conn_id = debug_info.servermonitor_connectionid;
  97
  98         info->client_monitor_pending = debug_info.clientmonitor_pending;
  99         info->client_monitor_latency = debug_info.clientmonitor_latency;
 100         info->client_monitor_conn_id = debug_info.clientmonitor_connectionid;
 101
 102         info->inbound.int_mask = debug_info.inbound.current_interrupt_mask;
 103         info->inbound.read_idx = debug_info.inbound.current_read_index;
 104         info->inbound.write_idx = debug_info.inbound.current_write_index;
 105         info->inbound.bytes_avail_toread =
 106                 debug_info.inbound.bytes_avail_toread;
 107         info->inbound.bytes_avail_towrite =
 108                 debug_info.inbound.bytes_avail_towrite;
 109
 110         info->outbound.int_mask =
 111                 debug_info.outbound.current_interrupt_mask;
 112         info->outbound.read_idx = debug_info.outbound.current_read_index;
 113         info->outbound.write_idx = debug_info.outbound.current_write_index;
 114         info->outbound.bytes_avail_toread =
 115                 debug_info.outbound.bytes_avail_toread;
 116         info->outbound.bytes_avail_towrite =
 117                 debug_info.outbound.bytes_avail_towrite;
 118 }
 119
 120 #define VMBUS_ALIAS_LEN ((sizeof((struct hv_vmbus_device_id *)0)->guid) * 2)
 121 static void print_alias_name(struct hv_device *hv_dev, char *alias_name)
 122 {
 123         int i;
 124         for (i = 0; i < VMBUS_ALIAS_LEN; i += 2)
 125                 sprintf(&alias_name[i], "%02x", hv_dev->dev_type.b[i/2]);
 126 }
 127
 128 /*
 129  * vmbus_show_device_attr - Show the device attribute in sysfs.
 130  *
 131  * This is invoked when user does a
 132  * "cat /sys/bus/vmbus/devices/<busdevice>/<attr name>"
 133  */
 134 static ssize_t vmbus_show_device_attr(struct device *dev,
 135                                       struct device_attribute *dev_attr,
 136                                       char *buf)
 137 {
 138         struct hv_device *hv_dev = device_to_hv_device(dev);
 139         struct hv_device_info *device_info;
 140         char alias_name[VMBUS_ALIAS_LEN + 1];
 141         int ret = 0;
 142
 143         device_info = kzalloc(sizeof(struct hv_device_info), GFP_KERNEL);
 144         if (!device_info)
 145                 return ret;
 146
 147         get_channel_info(hv_dev, device_info);
 148
 149         if (!strcmp(dev_attr->attr.name, "class_id")) {
 150                 ret = sprintf(buf, "{%pUl}\n", device_info->chn_type.b);
 151         } else if (!strcmp(dev_attr->attr.name, "device_id")) {
 152                 ret = sprintf(buf, "{%pUl}\n", device_info->chn_instance.b);
 153         } else if (!strcmp(dev_attr->attr.name, "modalias")) {
 154                 print_alias_name(hv_dev, alias_name);
 155                 ret = sprintf(buf, "vmbus:%s\n", alias_name);
 156         } else if (!strcmp(dev_attr->attr.name, "state")) {
 157                 ret = sprintf(buf, "%d\n", device_info->chn_state);
 158         } else if (!strcmp(dev_attr->attr.name, "id")) {
 159                 ret = sprintf(buf, "%d\n", device_info->chn_id);
 160         } else if (!strcmp(dev_attr->attr.name, "out_intr_mask")) {
 161                 ret = sprintf(buf, "%d\n", device_info->outbound.int_mask);
 162         } else if (!strcmp(dev_attr->attr.name, "out_read_index")) {
 163                 ret = sprintf(buf, "%d\n", device_info->outbound.read_idx);
 164         } else if (!strcmp(dev_attr->attr.name, "out_write_index")) {
 165                 ret = sprintf(buf, "%d\n", device_info->outbound.write_idx);
 166         } else if (!strcmp(dev_attr->attr.name, "out_read_bytes_avail")) {
 167                 ret = sprintf(buf, "%d\n",
 168                                device_info->outbound.bytes_avail_toread);
 169         } else if (!strcmp(dev_attr->attr.name, "out_write_bytes_avail")) {
 170                 ret = sprintf(buf, "%d\n",
 171                                device_info->outbound.bytes_avail_towrite);
 172         } else if (!strcmp(dev_attr->attr.name, "in_intr_mask")) {
 173                 ret = sprintf(buf, "%d\n", device_info->inbound.int_mask);
 174         } else if (!strcmp(dev_attr->attr.name, "in_read_index")) {
 175                 ret = sprintf(buf, "%d\n", device_info->inbound.read_idx);
 176         } else if (!strcmp(dev_attr->attr.name, "in_write_index")) {
 177                 ret = sprintf(buf, "%d\n", device_info->inbound.write_idx);
 178         } else if (!strcmp(dev_attr->attr.name, "in_read_bytes_avail")) {
 179                 ret = sprintf(buf, "%d\n",
 180                                device_info->inbound.bytes_avail_toread);
 181         } else if (!strcmp(dev_attr->attr.name, "in_write_bytes_avail")) {
 182                 ret = sprintf(buf, "%d\n",
 183                                device_info->inbound.bytes_avail_towrite);
 184         } else if (!strcmp(dev_attr->attr.name, "monitor_id")) {
 185                 ret = sprintf(buf, "%d\n", device_info->monitor_id);
 186         } else if (!strcmp(dev_attr->attr.name, "server_monitor_pending")) {
 187                 ret = sprintf(buf, "%d\n", device_info->server_monitor_pending);
 188         } else if (!strcmp(dev_attr->attr.name, "server_monitor_latency")) {
 189                 ret = sprintf(buf, "%d\n", device_info->server_monitor_latency);
 190         } else if (!strcmp(dev_attr->attr.name, "server_monitor_conn_id")) {
 191                 ret = sprintf(buf, "%d\n",
 192                                device_info->server_monitor_conn_id);
 193         } else if (!strcmp(dev_attr->attr.name, "client_monitor_pending")) {
 194                 ret = sprintf(buf, "%d\n", device_info->client_monitor_pending);
 195         } else if (!strcmp(dev_attr->attr.name, "client_monitor_latency")) {
 196                 ret = sprintf(buf, "%d\n", device_info->client_monitor_latency);
 197         } else if (!strcmp(dev_attr->attr.name, "client_monitor_conn_id")) {
 198                 ret = sprintf(buf, "%d\n",
 199                                device_info->client_monitor_conn_id);
 200         }
 201
 202         kfree(device_info);
 203         return ret;
 204 }
 205
 206 /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
 207 static struct device_attribute vmbus_device_attrs[] = {
 208         __ATTR(id, S_IRUGO, vmbus_show_device_attr, NULL),
 209         __ATTR(state, S_IRUGO, vmbus_show_device_attr, NULL),
 210         __ATTR(class_id, S_IRUGO, vmbus_show_device_attr, NULL),
 211         __ATTR(device_id, S_IRUGO, vmbus_show_device_attr, NULL),
 212         __ATTR(monitor_id, S_IRUGO, vmbus_show_device_attr, NULL),
 213         __ATTR(modalias, S_IRUGO, vmbus_show_device_attr, NULL),
 214
 215         __ATTR(server_monitor_pending, S_IRUGO, vmbus_show_device_attr, NULL),
 216         __ATTR(server_monitor_latency, S_IRUGO, vmbus_show_device_attr, NULL),
 217         __ATTR(server_monitor_conn_id, S_IRUGO, vmbus_show_device_attr, NULL),
 218
 219         __ATTR(client_monitor_pending, S_IRUGO, vmbus_show_device_attr, NULL),
 220         __ATTR(client_monitor_latency, S_IRUGO, vmbus_show_device_attr, NULL),
 221         __ATTR(client_monitor_conn_id, S_IRUGO, vmbus_show_device_attr, NULL),
 222
 223         __ATTR(out_intr_mask, S_IRUGO, vmbus_show_device_attr, NULL),
 224         __ATTR(out_read_index, S_IRUGO, vmbus_show_device_attr, NULL),
 225         __ATTR(out_write_index, S_IRUGO, vmbus_show_device_attr, NULL),
 226         __ATTR(out_read_bytes_avail, S_IRUGO, vmbus_show_device_attr, NULL),
 227         __ATTR(out_write_bytes_avail, S_IRUGO, vmbus_show_device_attr, NULL),
 228
 229         __ATTR(in_intr_mask, S_IRUGO, vmbus_show_device_attr, NULL),
 230         __ATTR(in_read_index, S_IRUGO, vmbus_show_device_attr, NULL),
 231         __ATTR(in_write_index, S_IRUGO, vmbus_show_device_attr, NULL),
 232         __ATTR(in_read_bytes_avail, S_IRUGO, vmbus_show_device_attr, NULL),
 233         __ATTR(in_write_bytes_avail, S_IRUGO, vmbus_show_device_attr, NULL),
 234         __ATTR_NULL
 235 };
 236
 237
 238 /*
 239  * vmbus_uevent - add uevent for our device
 240  *
 241  * This routine is invoked when a device is added or removed on the vmbus to
 242  * generate a uevent to udev in the userspace. The udev will then look at its
 243  * rule and the uevent generated here to load the appropriate driver
 244  *
 245  * The alias string will be of the form vmbus:guid where guid is the string
 246  * representation of the device guid (each byte of the guid will be
 247  * represented with two hex characters.
 248  */
 249 static int vmbus_uevent(struct device *device, struct kobj_uevent_env *env)
 250 {
 251         struct hv_device *dev = device_to_hv_device(device);
 252         int ret;
 253         char alias_name[VMBUS_ALIAS_LEN + 1];
 254
 255         print_alias_name(dev, alias_name);
 256         ret = add_uevent_var(env, "MODALIAS=vmbus:%s", alias_name);
 257         return ret;
 258 }
 259
 260 static uuid_le null_guid;
 261
 262 static inline bool is_null_guid(const __u8 *guid)
 263 {
 264         if (memcmp(guid, &null_guid, sizeof(uuid_le)))
 265                 return false;
 266         return true;
 267 }
 268
 269 /*
 270  * Return a matching hv_vmbus_device_id pointer.
 271  * If there is no match, return NULL.
 272  */
 273 static const struct hv_vmbus_device_id *hv_vmbus_get_id(
 274                                         const struct hv_vmbus_device_id *id,
 275                                         __u8 *guid)
 276 {
 277         for (; !is_null_guid(id->guid); id++)
 278                 if (!memcmp(&id->guid, guid, sizeof(uuid_le)))
 279                         return id;
 280
 281         return NULL;
 282 }
 283
 284
 285
 286 /*
 287  * vmbus_match - Attempt to match the specified device to the specified driver
 288  */
 289 static int vmbus_match(struct device *device, struct device_driver *driver)
 290 {
 291         struct hv_driver *drv = drv_to_hv_drv(driver);
 292         struct hv_device *hv_dev = device_to_hv_device(device);
 293
 294         if (hv_vmbus_get_id(drv->id_table, hv_dev->dev_type.b))
 295                 return 1;
 296
 297         return 0;
 298 }
 299
 300 /*
 301  * vmbus_probe - Add the new vmbus's child device
 302  */
 303 static int vmbus_probe(struct device *child_device)
 304 {
 305         int ret = 0;
 306         struct hv_driver *drv =
 307                         drv_to_hv_drv(child_device->driver);
 308         struct hv_device *dev = device_to_hv_device(child_device);
 309         const struct hv_vmbus_device_id *dev_id;
 310
 311         dev_id = hv_vmbus_get_id(drv->id_table, dev->dev_type.b);
 312         if (drv->probe) {
 313                 ret = drv->probe(dev, dev_id);
 314                 if (ret != 0)
 315                         pr_err("probe failed for device %s (%d)\n",
 316                                dev_name(child_device), ret);
 317
 318         } else {
 319                 pr_err("probe not set for driver %s\n",
 320                        dev_name(child_device));
 321                 ret = -ENODEV;
 322         }
 323         return ret;
 324 }
 325
 326 /*
 327  * vmbus_remove - Remove a vmbus device
 328  */
 329 static int vmbus_remove(struct device *child_device)
 330 {
 331         struct hv_driver *drv = drv_to_hv_drv(child_device->driver);
 332         struct hv_device *dev = device_to_hv_device(child_device);
 333
 334         if (drv->remove)
 335                 drv->remove(dev);
 336         else
 337                 pr_err("remove not set for driver %s\n",
 338                         dev_name(child_device));
 339
 340         return 0;
 341 }
 342
 343
 344 /*
 345  * vmbus_shutdown - Shutdown a vmbus device
 346  */
 347 static void vmbus_shutdown(struct device *child_device)
 348 {
 349         struct hv_driver *drv;
 350         struct hv_device *dev = device_to_hv_device(child_device);
 351
 352
 353         /* The device may not be attached yet */
 354         if (!child_device->driver)
 355                 return;
 356
 357         drv = drv_to_hv_drv(child_device->driver);
 358
 359         if (drv->shutdown)
 360                 drv->shutdown(dev);
 361
 362         return;
 363 }
 364
 365
 366 /*
 367  * vmbus_device_release - Final callback release of the vmbus child device
 368  */
 369 static void vmbus_device_release(struct device *device)
 370 {
 371         struct hv_device *hv_dev = device_to_hv_device(device);
 372
 373         kfree(hv_dev);
 374
 375 }
 376
 377 /* The one and only one */
 378 static struct bus_type  hv_bus = {
 379         .name =         "vmbus",
 380         .match =                vmbus_match,
 381         .shutdown =             vmbus_shutdown,
 382         .remove =               vmbus_remove,
 383         .probe =                vmbus_probe,
 384         .uevent =               vmbus_uevent,
 385         .dev_attrs =    vmbus_device_attrs,
 386 };
 387
 388 static const char *driver_name = "hyperv";
 389
 390
 391 struct onmessage_work_context {
 392         struct work_struct work;
 393         struct hv_message msg;
 394 };
 395
 396 static void vmbus_onmessage_work(struct work_struct *work)
 397 {
 398         struct onmessage_work_context *ctx;
 399
 400         ctx = container_of(work, struct onmessage_work_context,
 401                            work);
 402         vmbus_onmessage(&ctx->msg);
 403         kfree(ctx);
 404 }
 405
 406 static void vmbus_on_msg_dpc(unsigned long data)
 407 {
 408         int cpu = smp_processor_id();
 409         void *page_addr = hv_context.synic_message_page[cpu];
 410         struct hv_message *msg = (struct hv_message *)page_addr +
 411                                   VMBUS_MESSAGE_SINT;
 412         struct onmessage_work_context *ctx;
 413
 414         while (1) {
 415                 if (msg->header.message_type == HVMSG_NONE) {
 416                         /* no msg */
 417                         break;
 418                 } else {
 419                         ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
 420                         if (ctx == NULL)
 421                                 continue;
 422                         INIT_WORK(&ctx->work, vmbus_onmessage_work);
 423                         memcpy(&ctx->msg, msg, sizeof(*msg));
 424                         queue_work(vmbus_connection.work_queue, &ctx->work);
 425                 }
 426
 427                 msg->header.message_type = HVMSG_NONE;
 428
 429                 /*
 430                  * Make sure the write to MessageType (ie set to
 431                  * HVMSG_NONE) happens before we read the
 432                  * MessagePending and EOMing. Otherwise, the EOMing
 433                  * will not deliver any more messages since there is
 434                  * no empty slot
 435                  */
 436                 smp_mb();
 437
 438                 if (msg->header.message_flags.msg_pending) {
 439                         /*
 440                          * This will cause message queue rescan to
 441                          * possibly deliver another msg from the
 442                          * hypervisor
 443                          */
 444                         wrmsrl(HV_X64_MSR_EOM, 0);
 445                 }
 446         }
 447 }
 448
 449 static irqreturn_t vmbus_isr(int irq, void *dev_id)
 450 {
 451         int cpu = smp_processor_id();
 452         void *page_addr;
 453         struct hv_message *msg;
 454         union hv_synic_event_flags *event;
 455         bool handled = false;
 456
 457         /*
 458          * Check for events before checking for messages. This is the order
 459          * in which events and messages are checked in Windows guests on
 460          * Hyper-V, and the Windows team suggested we do the same.
 461          */
 462
 463         page_addr = hv_context.synic_event_page[cpu];
 464         event = (union hv_synic_event_flags *)page_addr + VMBUS_MESSAGE_SINT;
 465
 466         /* Since we are a child, we only need to check bit 0 */
 467         if (sync_test_and_clear_bit(0, (unsigned long *) &event->flags32[0])) {
 468                 handled = true;
 469                 tasklet_schedule(&event_dpc);
 470         }
 471
 472         page_addr = hv_context.synic_message_page[cpu];
 473         msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
 474
 475         /* Check if there are actual msgs to be processed */
 476         if (msg->header.message_type != HVMSG_NONE) {
 477                 handled = true;
 478                 tasklet_schedule(&msg_dpc);
 479         }
 480
 481         if (handled)
 482                 return IRQ_HANDLED;
 483         else
 484                 return IRQ_NONE;
 485 }
 486
 487 /*
 488  * vmbus_bus_init -Main vmbus driver initialization routine.
 489  *
 490  * Here, we
 491  *      - initialize the vmbus driver context
 492  *      - invoke the vmbus hv main init routine
 493  *      - get the irq resource
 494  *      - retrieve the channel offers
 495  */
 496 static int vmbus_bus_init(int irq)
 497 {
 498         int ret;
 499         unsigned int vector;
 500
 501         /* Hypervisor initialization...setup hypercall page..etc */
 502         ret = hv_init();
 503         if (ret != 0) {
 504                 pr_err("Unable to initialize the hypervisor - 0x%x\n", ret);
 505                 return ret;
 506         }
 507
 508         tasklet_init(&msg_dpc, vmbus_on_msg_dpc, 0);
 509         tasklet_init(&event_dpc, vmbus_on_event, 0);
 510
 511         ret = bus_register(&hv_bus);
 512         if (ret)
 513                 goto err_cleanup;
 514
 515         ret = request_irq(irq, vmbus_isr, 0, driver_name, hv_acpi_dev);
 516
 517         if (ret != 0) {
 518                 pr_err("Unable to request IRQ %d\n",
 519                            irq);
 520                 goto err_unregister;
 521         }
 522
 523         vector = IRQ0_VECTOR + irq;
 524
 525         /*
 526          * Notify the hypervisor of our irq and
 527          * connect to the host.
 528          */
 529         on_each_cpu(hv_synic_init, (void *)&vector, 1);
 530         ret = vmbus_connect();
 531         if (ret)
 532                 goto err_irq;
 533
 534         vmbus_request_offers();
 535
 536         return 0;
 537
 538 err_irq:
 539         free_irq(irq, hv_acpi_dev);
 540
 541 err_unregister:
 542         bus_unregister(&hv_bus);
 543
 544 err_cleanup:
 545         hv_cleanup();
 546
 547         return ret;
 548 }
 549
 550 /**
 551  * __vmbus_child_driver_register - Register a vmbus's driver
 552  * @drv: Pointer to driver structure you want to register
 553  * @owner: owner module of the drv
 554  * @mod_name: module name string
 555  *
 556  * Registers the given driver with Linux through the 'driver_register()' call
 557  * and sets up the hyper-v vmbus handling for this driver.
 558  * It will return the state of the 'driver_register()' call.
 559  *
 560  */
 561 int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, const char *mod_name)
 562 {
 563         int ret;
 564
 565         pr_info("registering driver %s\n", hv_driver->name);
 566
 567         ret = vmbus_exists();
 568         if (ret < 0)
 569                 return ret;
 570
 571         hv_driver->driver.name = hv_driver->name;
 572         hv_driver->driver.owner = owner;
 573         hv_driver->driver.mod_name = mod_name;
 574         hv_driver->driver.bus = &hv_bus;
 575
 576         ret = driver_register(&hv_driver->driver);
 577
 578         vmbus_request_offers();
 579
 580         return ret;
 581 }
 582 EXPORT_SYMBOL_GPL(__vmbus_driver_register);
 583
 584 /**
 585  * vmbus_driver_unregister() - Unregister a vmbus's driver
 586  * @drv: Pointer to driver structure you want to un-register
 587  *
 588  * Un-register the given driver that was previous registered with a call to
 589  * vmbus_driver_register()
 590  */
 591 void vmbus_driver_unregister(struct hv_driver *hv_driver)
 592 {
 593         pr_info("unregistering driver %s\n", hv_driver->name);
 594
 595         if (!vmbus_exists())
 596                 driver_unregister(&hv_driver->driver);
 597 }
 598 EXPORT_SYMBOL_GPL(vmbus_driver_unregister);
 599
 600 /*
 601  * vmbus_device_create - Creates and registers a new child device
 602  * on the vmbus.
 603  */
 604 struct hv_device *vmbus_device_create(uuid_le *type,
 605                                             uuid_le *instance,
 606                                             struct vmbus_channel *channel)
 607 {
 608         struct hv_device *child_device_obj;
 609
 610         child_device_obj = kzalloc(sizeof(struct hv_device), GFP_KERNEL);
 611         if (!child_device_obj) {
 612                 pr_err("Unable to allocate device object for child device\n");
 613                 return NULL;
 614         }
 615
 616         child_device_obj->channel = channel;
 617         memcpy(&child_device_obj->dev_type, type, sizeof(uuid_le));
 618         memcpy(&child_device_obj->dev_instance, instance,
 619                sizeof(uuid_le));
 620
 621
 622         return child_device_obj;
 623 }
 624
 625 /*
 626  * vmbus_device_register - Register the child device
 627  */
 628 int vmbus_device_register(struct hv_device *child_device_obj)
 629 {
 630         int ret = 0;
 631
 632         static atomic_t device_num = ATOMIC_INIT(0);
 633
 634         dev_set_name(&child_device_obj->device, "vmbus_0_%d",
 635                      atomic_inc_return(&device_num));
 636
 637         child_device_obj->device.bus = &hv_bus;
 638         child_device_obj->device.parent = &hv_acpi_dev->dev;
 639         child_device_obj->device.release = vmbus_device_release;
 640
 641         /*
 642          * Register with the LDM. This will kick off the driver/device
 643          * binding...which will eventually call vmbus_match() and vmbus_probe()
 644          */
 645         ret = device_register(&child_device_obj->device);
 646
 647         if (ret)
 648                 pr_err("Unable to register child device\n");
 649         else
 650                 pr_info("child device %s registered\n",
 651                         dev_name(&child_device_obj->device));
 652
 653         return ret;
 654 }
 655
 656 /*
 657  * vmbus_device_unregister - Remove the specified child device
 658  * from the vmbus.
 659  */
 660 void vmbus_device_unregister(struct hv_device *device_obj)
 661 {
 662         /*
 663          * Kick off the process of unregistering the device.
 664          * This will call vmbus_remove() and eventually vmbus_device_release()
 665          */
 666         device_unregister(&device_obj->device);
 667
 668         pr_info("child device %s unregistered\n",
 669                 dev_name(&device_obj->device));
 670 }
 671
 672
 673 /*
 674  * VMBUS is an acpi enumerated device. Get the the IRQ information
 675  * from DSDT.
 676  */
 677
 678 static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *irq)
 679 {
 680
 681         if (res->type == ACPI_RESOURCE_TYPE_IRQ) {
 682                 struct acpi_resource_irq *irqp;
 683                 irqp = &res->data.irq;
 684
 685                 *((unsigned int *)irq) = irqp->interrupts[0];
 686         }
 687
 688         return AE_OK;
 689 }
 690
 691 static int vmbus_acpi_add(struct acpi_device *device)
 692 {
 693         acpi_status result;
 694
 695         hv_acpi_dev = device;
 696
 697         result = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 698                                         vmbus_walk_resources, &irq);
 699
 700         if (ACPI_FAILURE(result)) {
 701                 complete(&probe_event);
 702                 return -ENODEV;
 703         }
 704         complete(&probe_event);
 705         return 0;
 706 }
 707
 708 static const struct acpi_device_id vmbus_acpi_device_ids[] = {
 709         {"VMBUS", 0},
 710         {"VMBus", 0},
 711         {"", 0},
 712 };
 713 MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
 714
 715 static struct acpi_driver vmbus_acpi_driver = {
 716         .name = "vmbus",
 717         .ids = vmbus_acpi_device_ids,
 718         .ops = {
 719                 .add = vmbus_acpi_add,
 720         },
 721 };
 722
 723 static int __init hv_acpi_init(void)
 724 {
 725         int ret, t;
 726
 727         if (x86_hyper != &x86_hyper_ms_hyperv)
 728                 return -ENODEV;
 729
 730         init_completion(&probe_event);
 731
 732         /*
 733          * Get irq resources first.
 734          */
 735
 736         ret = acpi_bus_register_driver(&vmbus_acpi_driver);
 737
 738         if (ret)
 739                 return ret;
 740
 741         t = wait_for_completion_timeout(&probe_event, 5*HZ);
 742         if (t == 0) {
 743                 ret = -ETIMEDOUT;
 744                 goto cleanup;
 745         }
 746
 747         if (irq <= 0) {
 748                 ret = -ENODEV;
 749                 goto cleanup;
 750         }
 751
 752         ret = vmbus_bus_init(irq);
 753         if (ret)
 754                 goto cleanup;
 755
 756         return 0;
 757
 758 cleanup:
 759         acpi_bus_unregister_driver(&vmbus_acpi_driver);
 760         hv_acpi_dev = NULL;
 761         return ret;
 762 }
 763
 764 static void __exit vmbus_exit(void)
 765 {
 766
 767         free_irq(irq, hv_acpi_dev);
 768         vmbus_free_channels();
 769         bus_unregister(&hv_bus);
 770         hv_cleanup();
 771         acpi_bus_unregister_driver(&vmbus_acpi_driver);
 772 }
 773
 774
 775 MODULE_LICENSE("GPL");
 776 MODULE_VERSION(HV_DRV_VERSION);
 777
 778 subsys_initcall(hv_acpi_init);
 779 module_exit(vmbus_exit);