xref: /openbmc/linux/drivers/hv/vmbus_drv.c (revision 95e9fd10)
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 "hyperv_vmbus.h"
38 
39 
40 static struct acpi_device  *hv_acpi_dev;
41 
42 static struct tasklet_struct msg_dpc;
43 static struct tasklet_struct event_dpc;
44 static struct completion probe_event;
45 static int irq;
46 
47 struct hv_device_info {
48 	u32 chn_id;
49 	u32 chn_state;
50 	uuid_le chn_type;
51 	uuid_le chn_instance;
52 
53 	u32 monitor_id;
54 	u32 server_monitor_pending;
55 	u32 server_monitor_latency;
56 	u32 server_monitor_conn_id;
57 	u32 client_monitor_pending;
58 	u32 client_monitor_latency;
59 	u32 client_monitor_conn_id;
60 
61 	struct hv_dev_port_info inbound;
62 	struct hv_dev_port_info outbound;
63 };
64 
65 static int vmbus_exists(void)
66 {
67 	if (hv_acpi_dev == NULL)
68 		return -ENODEV;
69 
70 	return 0;
71 }
72 
73 
74 static void get_channel_info(struct hv_device *device,
75 			     struct hv_device_info *info)
76 {
77 	struct vmbus_channel_debug_info debug_info;
78 
79 	if (!device->channel)
80 		return;
81 
82 	vmbus_get_debug_info(device->channel, &debug_info);
83 
84 	info->chn_id = debug_info.relid;
85 	info->chn_state = debug_info.state;
86 	memcpy(&info->chn_type, &debug_info.interfacetype,
87 	       sizeof(uuid_le));
88 	memcpy(&info->chn_instance, &debug_info.interface_instance,
89 	       sizeof(uuid_le));
90 
91 	info->monitor_id = debug_info.monitorid;
92 
93 	info->server_monitor_pending = debug_info.servermonitor_pending;
94 	info->server_monitor_latency = debug_info.servermonitor_latency;
95 	info->server_monitor_conn_id = debug_info.servermonitor_connectionid;
96 
97 	info->client_monitor_pending = debug_info.clientmonitor_pending;
98 	info->client_monitor_latency = debug_info.clientmonitor_latency;
99 	info->client_monitor_conn_id = debug_info.clientmonitor_connectionid;
100 
101 	info->inbound.int_mask = debug_info.inbound.current_interrupt_mask;
102 	info->inbound.read_idx = debug_info.inbound.current_read_index;
103 	info->inbound.write_idx = debug_info.inbound.current_write_index;
104 	info->inbound.bytes_avail_toread =
105 		debug_info.inbound.bytes_avail_toread;
106 	info->inbound.bytes_avail_towrite =
107 		debug_info.inbound.bytes_avail_towrite;
108 
109 	info->outbound.int_mask =
110 		debug_info.outbound.current_interrupt_mask;
111 	info->outbound.read_idx = debug_info.outbound.current_read_index;
112 	info->outbound.write_idx = debug_info.outbound.current_write_index;
113 	info->outbound.bytes_avail_toread =
114 		debug_info.outbound.bytes_avail_toread;
115 	info->outbound.bytes_avail_towrite =
116 		debug_info.outbound.bytes_avail_towrite;
117 }
118 
119 #define VMBUS_ALIAS_LEN ((sizeof((struct hv_vmbus_device_id *)0)->guid) * 2)
120 static void print_alias_name(struct hv_device *hv_dev, char *alias_name)
121 {
122 	int i;
123 	for (i = 0; i < VMBUS_ALIAS_LEN; i += 2)
124 		sprintf(&alias_name[i], "%02x", hv_dev->dev_type.b[i/2]);
125 }
126 
127 /*
128  * vmbus_show_device_attr - Show the device attribute in sysfs.
129  *
130  * This is invoked when user does a
131  * "cat /sys/bus/vmbus/devices/<busdevice>/<attr name>"
132  */
133 static ssize_t vmbus_show_device_attr(struct device *dev,
134 				      struct device_attribute *dev_attr,
135 				      char *buf)
136 {
137 	struct hv_device *hv_dev = device_to_hv_device(dev);
138 	struct hv_device_info *device_info;
139 	char alias_name[VMBUS_ALIAS_LEN + 1];
140 	int ret = 0;
141 
142 	device_info = kzalloc(sizeof(struct hv_device_info), GFP_KERNEL);
143 	if (!device_info)
144 		return ret;
145 
146 	get_channel_info(hv_dev, device_info);
147 
148 	if (!strcmp(dev_attr->attr.name, "class_id")) {
149 		ret = sprintf(buf, "{%02x%02x%02x%02x-%02x%02x-%02x%02x-"
150 			       "%02x%02x%02x%02x%02x%02x%02x%02x}\n",
151 			       device_info->chn_type.b[3],
152 			       device_info->chn_type.b[2],
153 			       device_info->chn_type.b[1],
154 			       device_info->chn_type.b[0],
155 			       device_info->chn_type.b[5],
156 			       device_info->chn_type.b[4],
157 			       device_info->chn_type.b[7],
158 			       device_info->chn_type.b[6],
159 			       device_info->chn_type.b[8],
160 			       device_info->chn_type.b[9],
161 			       device_info->chn_type.b[10],
162 			       device_info->chn_type.b[11],
163 			       device_info->chn_type.b[12],
164 			       device_info->chn_type.b[13],
165 			       device_info->chn_type.b[14],
166 			       device_info->chn_type.b[15]);
167 	} else if (!strcmp(dev_attr->attr.name, "device_id")) {
168 		ret = sprintf(buf, "{%02x%02x%02x%02x-%02x%02x-%02x%02x-"
169 			       "%02x%02x%02x%02x%02x%02x%02x%02x}\n",
170 			       device_info->chn_instance.b[3],
171 			       device_info->chn_instance.b[2],
172 			       device_info->chn_instance.b[1],
173 			       device_info->chn_instance.b[0],
174 			       device_info->chn_instance.b[5],
175 			       device_info->chn_instance.b[4],
176 			       device_info->chn_instance.b[7],
177 			       device_info->chn_instance.b[6],
178 			       device_info->chn_instance.b[8],
179 			       device_info->chn_instance.b[9],
180 			       device_info->chn_instance.b[10],
181 			       device_info->chn_instance.b[11],
182 			       device_info->chn_instance.b[12],
183 			       device_info->chn_instance.b[13],
184 			       device_info->chn_instance.b[14],
185 			       device_info->chn_instance.b[15]);
186 	} else if (!strcmp(dev_attr->attr.name, "modalias")) {
187 		print_alias_name(hv_dev, alias_name);
188 		ret = sprintf(buf, "vmbus:%s\n", alias_name);
189 	} else if (!strcmp(dev_attr->attr.name, "state")) {
190 		ret = sprintf(buf, "%d\n", device_info->chn_state);
191 	} else if (!strcmp(dev_attr->attr.name, "id")) {
192 		ret = sprintf(buf, "%d\n", device_info->chn_id);
193 	} else if (!strcmp(dev_attr->attr.name, "out_intr_mask")) {
194 		ret = sprintf(buf, "%d\n", device_info->outbound.int_mask);
195 	} else if (!strcmp(dev_attr->attr.name, "out_read_index")) {
196 		ret = sprintf(buf, "%d\n", device_info->outbound.read_idx);
197 	} else if (!strcmp(dev_attr->attr.name, "out_write_index")) {
198 		ret = sprintf(buf, "%d\n", device_info->outbound.write_idx);
199 	} else if (!strcmp(dev_attr->attr.name, "out_read_bytes_avail")) {
200 		ret = sprintf(buf, "%d\n",
201 			       device_info->outbound.bytes_avail_toread);
202 	} else if (!strcmp(dev_attr->attr.name, "out_write_bytes_avail")) {
203 		ret = sprintf(buf, "%d\n",
204 			       device_info->outbound.bytes_avail_towrite);
205 	} else if (!strcmp(dev_attr->attr.name, "in_intr_mask")) {
206 		ret = sprintf(buf, "%d\n", device_info->inbound.int_mask);
207 	} else if (!strcmp(dev_attr->attr.name, "in_read_index")) {
208 		ret = sprintf(buf, "%d\n", device_info->inbound.read_idx);
209 	} else if (!strcmp(dev_attr->attr.name, "in_write_index")) {
210 		ret = sprintf(buf, "%d\n", device_info->inbound.write_idx);
211 	} else if (!strcmp(dev_attr->attr.name, "in_read_bytes_avail")) {
212 		ret = sprintf(buf, "%d\n",
213 			       device_info->inbound.bytes_avail_toread);
214 	} else if (!strcmp(dev_attr->attr.name, "in_write_bytes_avail")) {
215 		ret = sprintf(buf, "%d\n",
216 			       device_info->inbound.bytes_avail_towrite);
217 	} else if (!strcmp(dev_attr->attr.name, "monitor_id")) {
218 		ret = sprintf(buf, "%d\n", device_info->monitor_id);
219 	} else if (!strcmp(dev_attr->attr.name, "server_monitor_pending")) {
220 		ret = sprintf(buf, "%d\n", device_info->server_monitor_pending);
221 	} else if (!strcmp(dev_attr->attr.name, "server_monitor_latency")) {
222 		ret = sprintf(buf, "%d\n", device_info->server_monitor_latency);
223 	} else if (!strcmp(dev_attr->attr.name, "server_monitor_conn_id")) {
224 		ret = sprintf(buf, "%d\n",
225 			       device_info->server_monitor_conn_id);
226 	} else if (!strcmp(dev_attr->attr.name, "client_monitor_pending")) {
227 		ret = sprintf(buf, "%d\n", device_info->client_monitor_pending);
228 	} else if (!strcmp(dev_attr->attr.name, "client_monitor_latency")) {
229 		ret = sprintf(buf, "%d\n", device_info->client_monitor_latency);
230 	} else if (!strcmp(dev_attr->attr.name, "client_monitor_conn_id")) {
231 		ret = sprintf(buf, "%d\n",
232 			       device_info->client_monitor_conn_id);
233 	}
234 
235 	kfree(device_info);
236 	return ret;
237 }
238 
239 /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
240 static struct device_attribute vmbus_device_attrs[] = {
241 	__ATTR(id, S_IRUGO, vmbus_show_device_attr, NULL),
242 	__ATTR(state, S_IRUGO, vmbus_show_device_attr, NULL),
243 	__ATTR(class_id, S_IRUGO, vmbus_show_device_attr, NULL),
244 	__ATTR(device_id, S_IRUGO, vmbus_show_device_attr, NULL),
245 	__ATTR(monitor_id, S_IRUGO, vmbus_show_device_attr, NULL),
246 	__ATTR(modalias, S_IRUGO, vmbus_show_device_attr, NULL),
247 
248 	__ATTR(server_monitor_pending, S_IRUGO, vmbus_show_device_attr, NULL),
249 	__ATTR(server_monitor_latency, S_IRUGO, vmbus_show_device_attr, NULL),
250 	__ATTR(server_monitor_conn_id, S_IRUGO, vmbus_show_device_attr, NULL),
251 
252 	__ATTR(client_monitor_pending, S_IRUGO, vmbus_show_device_attr, NULL),
253 	__ATTR(client_monitor_latency, S_IRUGO, vmbus_show_device_attr, NULL),
254 	__ATTR(client_monitor_conn_id, S_IRUGO, vmbus_show_device_attr, NULL),
255 
256 	__ATTR(out_intr_mask, S_IRUGO, vmbus_show_device_attr, NULL),
257 	__ATTR(out_read_index, S_IRUGO, vmbus_show_device_attr, NULL),
258 	__ATTR(out_write_index, S_IRUGO, vmbus_show_device_attr, NULL),
259 	__ATTR(out_read_bytes_avail, S_IRUGO, vmbus_show_device_attr, NULL),
260 	__ATTR(out_write_bytes_avail, S_IRUGO, vmbus_show_device_attr, NULL),
261 
262 	__ATTR(in_intr_mask, S_IRUGO, vmbus_show_device_attr, NULL),
263 	__ATTR(in_read_index, S_IRUGO, vmbus_show_device_attr, NULL),
264 	__ATTR(in_write_index, S_IRUGO, vmbus_show_device_attr, NULL),
265 	__ATTR(in_read_bytes_avail, S_IRUGO, vmbus_show_device_attr, NULL),
266 	__ATTR(in_write_bytes_avail, S_IRUGO, vmbus_show_device_attr, NULL),
267 	__ATTR_NULL
268 };
269 
270 
271 /*
272  * vmbus_uevent - add uevent for our device
273  *
274  * This routine is invoked when a device is added or removed on the vmbus to
275  * generate a uevent to udev in the userspace. The udev will then look at its
276  * rule and the uevent generated here to load the appropriate driver
277  *
278  * The alias string will be of the form vmbus:guid where guid is the string
279  * representation of the device guid (each byte of the guid will be
280  * represented with two hex characters.
281  */
282 static int vmbus_uevent(struct device *device, struct kobj_uevent_env *env)
283 {
284 	struct hv_device *dev = device_to_hv_device(device);
285 	int ret;
286 	char alias_name[VMBUS_ALIAS_LEN + 1];
287 
288 	print_alias_name(dev, alias_name);
289 	ret = add_uevent_var(env, "MODALIAS=vmbus:%s", alias_name);
290 	return ret;
291 }
292 
293 static uuid_le null_guid;
294 
295 static inline bool is_null_guid(const __u8 *guid)
296 {
297 	if (memcmp(guid, &null_guid, sizeof(uuid_le)))
298 		return false;
299 	return true;
300 }
301 
302 /*
303  * Return a matching hv_vmbus_device_id pointer.
304  * If there is no match, return NULL.
305  */
306 static const struct hv_vmbus_device_id *hv_vmbus_get_id(
307 					const struct hv_vmbus_device_id *id,
308 					__u8 *guid)
309 {
310 	for (; !is_null_guid(id->guid); id++)
311 		if (!memcmp(&id->guid, guid, sizeof(uuid_le)))
312 			return id;
313 
314 	return NULL;
315 }
316 
317 
318 
319 /*
320  * vmbus_match - Attempt to match the specified device to the specified driver
321  */
322 static int vmbus_match(struct device *device, struct device_driver *driver)
323 {
324 	struct hv_driver *drv = drv_to_hv_drv(driver);
325 	struct hv_device *hv_dev = device_to_hv_device(device);
326 
327 	if (hv_vmbus_get_id(drv->id_table, hv_dev->dev_type.b))
328 		return 1;
329 
330 	return 0;
331 }
332 
333 /*
334  * vmbus_probe - Add the new vmbus's child device
335  */
336 static int vmbus_probe(struct device *child_device)
337 {
338 	int ret = 0;
339 	struct hv_driver *drv =
340 			drv_to_hv_drv(child_device->driver);
341 	struct hv_device *dev = device_to_hv_device(child_device);
342 	const struct hv_vmbus_device_id *dev_id;
343 
344 	dev_id = hv_vmbus_get_id(drv->id_table, dev->dev_type.b);
345 	if (drv->probe) {
346 		ret = drv->probe(dev, dev_id);
347 		if (ret != 0)
348 			pr_err("probe failed for device %s (%d)\n",
349 			       dev_name(child_device), ret);
350 
351 	} else {
352 		pr_err("probe not set for driver %s\n",
353 		       dev_name(child_device));
354 		ret = -ENODEV;
355 	}
356 	return ret;
357 }
358 
359 /*
360  * vmbus_remove - Remove a vmbus device
361  */
362 static int vmbus_remove(struct device *child_device)
363 {
364 	struct hv_driver *drv = drv_to_hv_drv(child_device->driver);
365 	struct hv_device *dev = device_to_hv_device(child_device);
366 
367 	if (drv->remove)
368 		drv->remove(dev);
369 	else
370 		pr_err("remove not set for driver %s\n",
371 			dev_name(child_device));
372 
373 	return 0;
374 }
375 
376 
377 /*
378  * vmbus_shutdown - Shutdown a vmbus device
379  */
380 static void vmbus_shutdown(struct device *child_device)
381 {
382 	struct hv_driver *drv;
383 	struct hv_device *dev = device_to_hv_device(child_device);
384 
385 
386 	/* The device may not be attached yet */
387 	if (!child_device->driver)
388 		return;
389 
390 	drv = drv_to_hv_drv(child_device->driver);
391 
392 	if (drv->shutdown)
393 		drv->shutdown(dev);
394 
395 	return;
396 }
397 
398 
399 /*
400  * vmbus_device_release - Final callback release of the vmbus child device
401  */
402 static void vmbus_device_release(struct device *device)
403 {
404 	struct hv_device *hv_dev = device_to_hv_device(device);
405 
406 	kfree(hv_dev);
407 
408 }
409 
410 /* The one and only one */
411 static struct bus_type  hv_bus = {
412 	.name =		"vmbus",
413 	.match =		vmbus_match,
414 	.shutdown =		vmbus_shutdown,
415 	.remove =		vmbus_remove,
416 	.probe =		vmbus_probe,
417 	.uevent =		vmbus_uevent,
418 	.dev_attrs =	vmbus_device_attrs,
419 };
420 
421 static const char *driver_name = "hyperv";
422 
423 
424 struct onmessage_work_context {
425 	struct work_struct work;
426 	struct hv_message msg;
427 };
428 
429 static void vmbus_onmessage_work(struct work_struct *work)
430 {
431 	struct onmessage_work_context *ctx;
432 
433 	ctx = container_of(work, struct onmessage_work_context,
434 			   work);
435 	vmbus_onmessage(&ctx->msg);
436 	kfree(ctx);
437 }
438 
439 static void vmbus_on_msg_dpc(unsigned long data)
440 {
441 	int cpu = smp_processor_id();
442 	void *page_addr = hv_context.synic_message_page[cpu];
443 	struct hv_message *msg = (struct hv_message *)page_addr +
444 				  VMBUS_MESSAGE_SINT;
445 	struct onmessage_work_context *ctx;
446 
447 	while (1) {
448 		if (msg->header.message_type == HVMSG_NONE) {
449 			/* no msg */
450 			break;
451 		} else {
452 			ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
453 			if (ctx == NULL)
454 				continue;
455 			INIT_WORK(&ctx->work, vmbus_onmessage_work);
456 			memcpy(&ctx->msg, msg, sizeof(*msg));
457 			queue_work(vmbus_connection.work_queue, &ctx->work);
458 		}
459 
460 		msg->header.message_type = HVMSG_NONE;
461 
462 		/*
463 		 * Make sure the write to MessageType (ie set to
464 		 * HVMSG_NONE) happens before we read the
465 		 * MessagePending and EOMing. Otherwise, the EOMing
466 		 * will not deliver any more messages since there is
467 		 * no empty slot
468 		 */
469 		smp_mb();
470 
471 		if (msg->header.message_flags.msg_pending) {
472 			/*
473 			 * This will cause message queue rescan to
474 			 * possibly deliver another msg from the
475 			 * hypervisor
476 			 */
477 			wrmsrl(HV_X64_MSR_EOM, 0);
478 		}
479 	}
480 }
481 
482 static irqreturn_t vmbus_isr(int irq, void *dev_id)
483 {
484 	int cpu = smp_processor_id();
485 	void *page_addr;
486 	struct hv_message *msg;
487 	union hv_synic_event_flags *event;
488 	bool handled = false;
489 
490 	/*
491 	 * Check for events before checking for messages. This is the order
492 	 * in which events and messages are checked in Windows guests on
493 	 * Hyper-V, and the Windows team suggested we do the same.
494 	 */
495 
496 	page_addr = hv_context.synic_event_page[cpu];
497 	event = (union hv_synic_event_flags *)page_addr + VMBUS_MESSAGE_SINT;
498 
499 	/* Since we are a child, we only need to check bit 0 */
500 	if (sync_test_and_clear_bit(0, (unsigned long *) &event->flags32[0])) {
501 		handled = true;
502 		tasklet_schedule(&event_dpc);
503 	}
504 
505 	page_addr = hv_context.synic_message_page[cpu];
506 	msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
507 
508 	/* Check if there are actual msgs to be processed */
509 	if (msg->header.message_type != HVMSG_NONE) {
510 		handled = true;
511 		tasklet_schedule(&msg_dpc);
512 	}
513 
514 	if (handled)
515 		return IRQ_HANDLED;
516 	else
517 		return IRQ_NONE;
518 }
519 
520 /*
521  * vmbus_bus_init -Main vmbus driver initialization routine.
522  *
523  * Here, we
524  *	- initialize the vmbus driver context
525  *	- invoke the vmbus hv main init routine
526  *	- get the irq resource
527  *	- retrieve the channel offers
528  */
529 static int vmbus_bus_init(int irq)
530 {
531 	int ret;
532 	unsigned int vector;
533 
534 	/* Hypervisor initialization...setup hypercall page..etc */
535 	ret = hv_init();
536 	if (ret != 0) {
537 		pr_err("Unable to initialize the hypervisor - 0x%x\n", ret);
538 		return ret;
539 	}
540 
541 	tasklet_init(&msg_dpc, vmbus_on_msg_dpc, 0);
542 	tasklet_init(&event_dpc, vmbus_on_event, 0);
543 
544 	ret = bus_register(&hv_bus);
545 	if (ret)
546 		goto err_cleanup;
547 
548 	ret = request_irq(irq, vmbus_isr, 0, driver_name, hv_acpi_dev);
549 
550 	if (ret != 0) {
551 		pr_err("Unable to request IRQ %d\n",
552 			   irq);
553 		goto err_unregister;
554 	}
555 
556 	vector = IRQ0_VECTOR + irq;
557 
558 	/*
559 	 * Notify the hypervisor of our irq and
560 	 * connect to the host.
561 	 */
562 	on_each_cpu(hv_synic_init, (void *)&vector, 1);
563 	ret = vmbus_connect();
564 	if (ret)
565 		goto err_irq;
566 
567 	vmbus_request_offers();
568 
569 	return 0;
570 
571 err_irq:
572 	free_irq(irq, hv_acpi_dev);
573 
574 err_unregister:
575 	bus_unregister(&hv_bus);
576 
577 err_cleanup:
578 	hv_cleanup();
579 
580 	return ret;
581 }
582 
583 /**
584  * __vmbus_child_driver_register - Register a vmbus's driver
585  * @drv: Pointer to driver structure you want to register
586  * @owner: owner module of the drv
587  * @mod_name: module name string
588  *
589  * Registers the given driver with Linux through the 'driver_register()' call
590  * and sets up the hyper-v vmbus handling for this driver.
591  * It will return the state of the 'driver_register()' call.
592  *
593  */
594 int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, const char *mod_name)
595 {
596 	int ret;
597 
598 	pr_info("registering driver %s\n", hv_driver->name);
599 
600 	ret = vmbus_exists();
601 	if (ret < 0)
602 		return ret;
603 
604 	hv_driver->driver.name = hv_driver->name;
605 	hv_driver->driver.owner = owner;
606 	hv_driver->driver.mod_name = mod_name;
607 	hv_driver->driver.bus = &hv_bus;
608 
609 	ret = driver_register(&hv_driver->driver);
610 
611 	vmbus_request_offers();
612 
613 	return ret;
614 }
615 EXPORT_SYMBOL_GPL(__vmbus_driver_register);
616 
617 /**
618  * vmbus_driver_unregister() - Unregister a vmbus's driver
619  * @drv: Pointer to driver structure you want to un-register
620  *
621  * Un-register the given driver that was previous registered with a call to
622  * vmbus_driver_register()
623  */
624 void vmbus_driver_unregister(struct hv_driver *hv_driver)
625 {
626 	pr_info("unregistering driver %s\n", hv_driver->name);
627 
628 	if (!vmbus_exists())
629 		driver_unregister(&hv_driver->driver);
630 }
631 EXPORT_SYMBOL_GPL(vmbus_driver_unregister);
632 
633 /*
634  * vmbus_device_create - Creates and registers a new child device
635  * on the vmbus.
636  */
637 struct hv_device *vmbus_device_create(uuid_le *type,
638 					    uuid_le *instance,
639 					    struct vmbus_channel *channel)
640 {
641 	struct hv_device *child_device_obj;
642 
643 	child_device_obj = kzalloc(sizeof(struct hv_device), GFP_KERNEL);
644 	if (!child_device_obj) {
645 		pr_err("Unable to allocate device object for child device\n");
646 		return NULL;
647 	}
648 
649 	child_device_obj->channel = channel;
650 	memcpy(&child_device_obj->dev_type, type, sizeof(uuid_le));
651 	memcpy(&child_device_obj->dev_instance, instance,
652 	       sizeof(uuid_le));
653 
654 
655 	return child_device_obj;
656 }
657 
658 /*
659  * vmbus_device_register - Register the child device
660  */
661 int vmbus_device_register(struct hv_device *child_device_obj)
662 {
663 	int ret = 0;
664 
665 	static atomic_t device_num = ATOMIC_INIT(0);
666 
667 	dev_set_name(&child_device_obj->device, "vmbus_0_%d",
668 		     atomic_inc_return(&device_num));
669 
670 	child_device_obj->device.bus = &hv_bus;
671 	child_device_obj->device.parent = &hv_acpi_dev->dev;
672 	child_device_obj->device.release = vmbus_device_release;
673 
674 	/*
675 	 * Register with the LDM. This will kick off the driver/device
676 	 * binding...which will eventually call vmbus_match() and vmbus_probe()
677 	 */
678 	ret = device_register(&child_device_obj->device);
679 
680 	if (ret)
681 		pr_err("Unable to register child device\n");
682 	else
683 		pr_info("child device %s registered\n",
684 			dev_name(&child_device_obj->device));
685 
686 	return ret;
687 }
688 
689 /*
690  * vmbus_device_unregister - Remove the specified child device
691  * from the vmbus.
692  */
693 void vmbus_device_unregister(struct hv_device *device_obj)
694 {
695 	/*
696 	 * Kick off the process of unregistering the device.
697 	 * This will call vmbus_remove() and eventually vmbus_device_release()
698 	 */
699 	device_unregister(&device_obj->device);
700 
701 	pr_info("child device %s unregistered\n",
702 		dev_name(&device_obj->device));
703 }
704 
705 
706 /*
707  * VMBUS is an acpi enumerated device. Get the the IRQ information
708  * from DSDT.
709  */
710 
711 static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *irq)
712 {
713 
714 	if (res->type == ACPI_RESOURCE_TYPE_IRQ) {
715 		struct acpi_resource_irq *irqp;
716 		irqp = &res->data.irq;
717 
718 		*((unsigned int *)irq) = irqp->interrupts[0];
719 	}
720 
721 	return AE_OK;
722 }
723 
724 static int vmbus_acpi_add(struct acpi_device *device)
725 {
726 	acpi_status result;
727 
728 	hv_acpi_dev = device;
729 
730 	result = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
731 					vmbus_walk_resources, &irq);
732 
733 	if (ACPI_FAILURE(result)) {
734 		complete(&probe_event);
735 		return -ENODEV;
736 	}
737 	complete(&probe_event);
738 	return 0;
739 }
740 
741 static const struct acpi_device_id vmbus_acpi_device_ids[] = {
742 	{"VMBUS", 0},
743 	{"VMBus", 0},
744 	{"", 0},
745 };
746 MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
747 
748 static struct acpi_driver vmbus_acpi_driver = {
749 	.name = "vmbus",
750 	.ids = vmbus_acpi_device_ids,
751 	.ops = {
752 		.add = vmbus_acpi_add,
753 	},
754 };
755 
756 static int __init hv_acpi_init(void)
757 {
758 	int ret, t;
759 
760 	init_completion(&probe_event);
761 
762 	/*
763 	 * Get irq resources first.
764 	 */
765 
766 	ret = acpi_bus_register_driver(&vmbus_acpi_driver);
767 
768 	if (ret)
769 		return ret;
770 
771 	t = wait_for_completion_timeout(&probe_event, 5*HZ);
772 	if (t == 0) {
773 		ret = -ETIMEDOUT;
774 		goto cleanup;
775 	}
776 
777 	if (irq <= 0) {
778 		ret = -ENODEV;
779 		goto cleanup;
780 	}
781 
782 	ret = vmbus_bus_init(irq);
783 	if (ret)
784 		goto cleanup;
785 
786 	return 0;
787 
788 cleanup:
789 	acpi_bus_unregister_driver(&vmbus_acpi_driver);
790 	hv_acpi_dev = NULL;
791 	return ret;
792 }
793 
794 static void __exit vmbus_exit(void)
795 {
796 
797 	free_irq(irq, hv_acpi_dev);
798 	vmbus_free_channels();
799 	bus_unregister(&hv_bus);
800 	hv_cleanup();
801 	acpi_bus_unregister_driver(&vmbus_acpi_driver);
802 }
803 
804 
805 MODULE_LICENSE("GPL");
806 MODULE_VERSION(HV_DRV_VERSION);
807 
808 subsys_initcall(hv_acpi_init);
809 module_exit(vmbus_exit);
810