xref: /openbmc/linux/drivers/hv/vmbus_drv.c (revision d0b73b48)
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);
780