xref: /openbmc/linux/drivers/hv/hv_util.c (revision 6abeae2a)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2010, Microsoft Corporation.
4  *
5  * Authors:
6  *   Haiyang Zhang <haiyangz@microsoft.com>
7  *   Hank Janssen  <hjanssen@microsoft.com>
8  */
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/sysctl.h>
16 #include <linux/reboot.h>
17 #include <linux/hyperv.h>
18 #include <linux/clockchips.h>
19 #include <linux/ptp_clock_kernel.h>
20 #include <clocksource/hyperv_timer.h>
21 #include <asm/mshyperv.h>
22 
23 #include "hyperv_vmbus.h"
24 
25 #define SD_MAJOR	3
26 #define SD_MINOR	0
27 #define SD_MINOR_1	1
28 #define SD_MINOR_2	2
29 #define SD_VERSION_3_1	(SD_MAJOR << 16 | SD_MINOR_1)
30 #define SD_VERSION_3_2	(SD_MAJOR << 16 | SD_MINOR_2)
31 #define SD_VERSION	(SD_MAJOR << 16 | SD_MINOR)
32 
33 #define SD_MAJOR_1	1
34 #define SD_VERSION_1	(SD_MAJOR_1 << 16 | SD_MINOR)
35 
36 #define TS_MAJOR	4
37 #define TS_MINOR	0
38 #define TS_VERSION	(TS_MAJOR << 16 | TS_MINOR)
39 
40 #define TS_MAJOR_1	1
41 #define TS_VERSION_1	(TS_MAJOR_1 << 16 | TS_MINOR)
42 
43 #define TS_MAJOR_3	3
44 #define TS_VERSION_3	(TS_MAJOR_3 << 16 | TS_MINOR)
45 
46 #define HB_MAJOR	3
47 #define HB_MINOR	0
48 #define HB_VERSION	(HB_MAJOR << 16 | HB_MINOR)
49 
50 #define HB_MAJOR_1	1
51 #define HB_VERSION_1	(HB_MAJOR_1 << 16 | HB_MINOR)
52 
53 static int sd_srv_version;
54 static int ts_srv_version;
55 static int hb_srv_version;
56 
57 #define SD_VER_COUNT 4
58 static const int sd_versions[] = {
59 	SD_VERSION_3_2,
60 	SD_VERSION_3_1,
61 	SD_VERSION,
62 	SD_VERSION_1
63 };
64 
65 #define TS_VER_COUNT 3
66 static const int ts_versions[] = {
67 	TS_VERSION,
68 	TS_VERSION_3,
69 	TS_VERSION_1
70 };
71 
72 #define HB_VER_COUNT 2
73 static const int hb_versions[] = {
74 	HB_VERSION,
75 	HB_VERSION_1
76 };
77 
78 #define FW_VER_COUNT 2
79 static const int fw_versions[] = {
80 	UTIL_FW_VERSION,
81 	UTIL_WS2K8_FW_VERSION
82 };
83 
84 /*
85  * Send the "hibernate" udev event in a thread context.
86  */
87 struct hibernate_work_context {
88 	struct work_struct work;
89 	struct hv_device *dev;
90 };
91 
92 static struct hibernate_work_context hibernate_context;
93 static bool hibernation_supported;
94 
95 static void send_hibernate_uevent(struct work_struct *work)
96 {
97 	char *uevent_env[2] = { "EVENT=hibernate", NULL };
98 	struct hibernate_work_context *ctx;
99 
100 	ctx = container_of(work, struct hibernate_work_context, work);
101 
102 	kobject_uevent_env(&ctx->dev->device.kobj, KOBJ_CHANGE, uevent_env);
103 
104 	pr_info("Sent hibernation uevent\n");
105 }
106 
107 static int hv_shutdown_init(struct hv_util_service *srv)
108 {
109 	struct vmbus_channel *channel = srv->channel;
110 
111 	INIT_WORK(&hibernate_context.work, send_hibernate_uevent);
112 	hibernate_context.dev = channel->device_obj;
113 
114 	hibernation_supported = hv_is_hibernation_supported();
115 
116 	return 0;
117 }
118 
119 static void shutdown_onchannelcallback(void *context);
120 static struct hv_util_service util_shutdown = {
121 	.util_cb = shutdown_onchannelcallback,
122 	.util_init = hv_shutdown_init,
123 };
124 
125 static int hv_timesync_init(struct hv_util_service *srv);
126 static int hv_timesync_pre_suspend(void);
127 static void hv_timesync_deinit(void);
128 
129 static void timesync_onchannelcallback(void *context);
130 static struct hv_util_service util_timesynch = {
131 	.util_cb = timesync_onchannelcallback,
132 	.util_init = hv_timesync_init,
133 	.util_pre_suspend = hv_timesync_pre_suspend,
134 	.util_deinit = hv_timesync_deinit,
135 };
136 
137 static void heartbeat_onchannelcallback(void *context);
138 static struct hv_util_service util_heartbeat = {
139 	.util_cb = heartbeat_onchannelcallback,
140 };
141 
142 static struct hv_util_service util_kvp = {
143 	.util_cb = hv_kvp_onchannelcallback,
144 	.util_init = hv_kvp_init,
145 	.util_pre_suspend = hv_kvp_pre_suspend,
146 	.util_pre_resume = hv_kvp_pre_resume,
147 	.util_deinit = hv_kvp_deinit,
148 };
149 
150 static struct hv_util_service util_vss = {
151 	.util_cb = hv_vss_onchannelcallback,
152 	.util_init = hv_vss_init,
153 	.util_pre_suspend = hv_vss_pre_suspend,
154 	.util_pre_resume = hv_vss_pre_resume,
155 	.util_deinit = hv_vss_deinit,
156 };
157 
158 static struct hv_util_service util_fcopy = {
159 	.util_cb = hv_fcopy_onchannelcallback,
160 	.util_init = hv_fcopy_init,
161 	.util_pre_suspend = hv_fcopy_pre_suspend,
162 	.util_pre_resume = hv_fcopy_pre_resume,
163 	.util_deinit = hv_fcopy_deinit,
164 };
165 
166 static void perform_shutdown(struct work_struct *dummy)
167 {
168 	orderly_poweroff(true);
169 }
170 
171 static void perform_restart(struct work_struct *dummy)
172 {
173 	orderly_reboot();
174 }
175 
176 /*
177  * Perform the shutdown operation in a thread context.
178  */
179 static DECLARE_WORK(shutdown_work, perform_shutdown);
180 
181 /*
182  * Perform the restart operation in a thread context.
183  */
184 static DECLARE_WORK(restart_work, perform_restart);
185 
186 static void shutdown_onchannelcallback(void *context)
187 {
188 	struct vmbus_channel *channel = context;
189 	struct work_struct *work = NULL;
190 	u32 recvlen;
191 	u64 requestid;
192 	u8  *shut_txf_buf = util_shutdown.recv_buffer;
193 
194 	struct shutdown_msg_data *shutdown_msg;
195 
196 	struct icmsg_hdr *icmsghdrp;
197 
198 	vmbus_recvpacket(channel, shut_txf_buf,
199 			 HV_HYP_PAGE_SIZE, &recvlen, &requestid);
200 
201 	if (recvlen > 0) {
202 		icmsghdrp = (struct icmsg_hdr *)&shut_txf_buf[
203 			sizeof(struct vmbuspipe_hdr)];
204 
205 		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
206 			if (vmbus_prep_negotiate_resp(icmsghdrp, shut_txf_buf,
207 					fw_versions, FW_VER_COUNT,
208 					sd_versions, SD_VER_COUNT,
209 					NULL, &sd_srv_version)) {
210 				pr_info("Shutdown IC version %d.%d\n",
211 					sd_srv_version >> 16,
212 					sd_srv_version & 0xFFFF);
213 			}
214 		} else {
215 			shutdown_msg =
216 				(struct shutdown_msg_data *)&shut_txf_buf[
217 					sizeof(struct vmbuspipe_hdr) +
218 					sizeof(struct icmsg_hdr)];
219 
220 			/*
221 			 * shutdown_msg->flags can be 0(shut down), 2(reboot),
222 			 * or 4(hibernate). It may bitwise-OR 1, which means
223 			 * performing the request by force. Linux always tries
224 			 * to perform the request by force.
225 			 */
226 			switch (shutdown_msg->flags) {
227 			case 0:
228 			case 1:
229 				icmsghdrp->status = HV_S_OK;
230 				work = &shutdown_work;
231 				pr_info("Shutdown request received -"
232 					    " graceful shutdown initiated\n");
233 				break;
234 			case 2:
235 			case 3:
236 				icmsghdrp->status = HV_S_OK;
237 				work = &restart_work;
238 				pr_info("Restart request received -"
239 					    " graceful restart initiated\n");
240 				break;
241 			case 4:
242 			case 5:
243 				pr_info("Hibernation request received\n");
244 				icmsghdrp->status = hibernation_supported ?
245 					HV_S_OK : HV_E_FAIL;
246 				if (hibernation_supported)
247 					work = &hibernate_context.work;
248 				break;
249 			default:
250 				icmsghdrp->status = HV_E_FAIL;
251 				pr_info("Shutdown request received -"
252 					    " Invalid request\n");
253 				break;
254 			}
255 		}
256 
257 		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
258 			| ICMSGHDRFLAG_RESPONSE;
259 
260 		vmbus_sendpacket(channel, shut_txf_buf,
261 				       recvlen, requestid,
262 				       VM_PKT_DATA_INBAND, 0);
263 	}
264 
265 	if (work)
266 		schedule_work(work);
267 }
268 
269 /*
270  * Set the host time in a process context.
271  */
272 static struct work_struct adj_time_work;
273 
274 /*
275  * The last time sample, received from the host. PTP device responds to
276  * requests by using this data and the current partition-wide time reference
277  * count.
278  */
279 static struct {
280 	u64				host_time;
281 	u64				ref_time;
282 	spinlock_t			lock;
283 } host_ts;
284 
285 static inline u64 reftime_to_ns(u64 reftime)
286 {
287 	return (reftime - WLTIMEDELTA) * 100;
288 }
289 
290 /*
291  * Hard coded threshold for host timesync delay: 600 seconds
292  */
293 static const u64 HOST_TIMESYNC_DELAY_THRESH = 600 * (u64)NSEC_PER_SEC;
294 
295 static int hv_get_adj_host_time(struct timespec64 *ts)
296 {
297 	u64 newtime, reftime, timediff_adj;
298 	unsigned long flags;
299 	int ret = 0;
300 
301 	spin_lock_irqsave(&host_ts.lock, flags);
302 	reftime = hv_read_reference_counter();
303 
304 	/*
305 	 * We need to let the caller know that last update from host
306 	 * is older than the max allowable threshold. clock_gettime()
307 	 * and PTP ioctl do not have a documented error that we could
308 	 * return for this specific case. Use ESTALE to report this.
309 	 */
310 	timediff_adj = reftime - host_ts.ref_time;
311 	if (timediff_adj * 100 > HOST_TIMESYNC_DELAY_THRESH) {
312 		pr_warn_once("TIMESYNC IC: Stale time stamp, %llu nsecs old\n",
313 			     (timediff_adj * 100));
314 		ret = -ESTALE;
315 	}
316 
317 	newtime = host_ts.host_time + timediff_adj;
318 	*ts = ns_to_timespec64(reftime_to_ns(newtime));
319 	spin_unlock_irqrestore(&host_ts.lock, flags);
320 
321 	return ret;
322 }
323 
324 static void hv_set_host_time(struct work_struct *work)
325 {
326 
327 	struct timespec64 ts;
328 
329 	if (!hv_get_adj_host_time(&ts))
330 		do_settimeofday64(&ts);
331 }
332 
333 /*
334  * Synchronize time with host after reboot, restore, etc.
335  *
336  * ICTIMESYNCFLAG_SYNC flag bit indicates reboot, restore events of the VM.
337  * After reboot the flag ICTIMESYNCFLAG_SYNC is included in the first time
338  * message after the timesync channel is opened. Since the hv_utils module is
339  * loaded after hv_vmbus, the first message is usually missed. This bit is
340  * considered a hard request to discipline the clock.
341  *
342  * ICTIMESYNCFLAG_SAMPLE bit indicates a time sample from host. This is
343  * typically used as a hint to the guest. The guest is under no obligation
344  * to discipline the clock.
345  */
346 static inline void adj_guesttime(u64 hosttime, u64 reftime, u8 adj_flags)
347 {
348 	unsigned long flags;
349 	u64 cur_reftime;
350 
351 	/*
352 	 * Save the adjusted time sample from the host and the snapshot
353 	 * of the current system time.
354 	 */
355 	spin_lock_irqsave(&host_ts.lock, flags);
356 
357 	cur_reftime = hv_read_reference_counter();
358 	host_ts.host_time = hosttime;
359 	host_ts.ref_time = cur_reftime;
360 
361 	/*
362 	 * TimeSync v4 messages contain reference time (guest's Hyper-V
363 	 * clocksource read when the time sample was generated), we can
364 	 * improve the precision by adding the delta between now and the
365 	 * time of generation. For older protocols we set
366 	 * reftime == cur_reftime on call.
367 	 */
368 	host_ts.host_time += (cur_reftime - reftime);
369 
370 	spin_unlock_irqrestore(&host_ts.lock, flags);
371 
372 	/* Schedule work to do do_settimeofday64() */
373 	if (adj_flags & ICTIMESYNCFLAG_SYNC)
374 		schedule_work(&adj_time_work);
375 }
376 
377 /*
378  * Time Sync Channel message handler.
379  */
380 static void timesync_onchannelcallback(void *context)
381 {
382 	struct vmbus_channel *channel = context;
383 	u32 recvlen;
384 	u64 requestid;
385 	struct icmsg_hdr *icmsghdrp;
386 	struct ictimesync_data *timedatap;
387 	struct ictimesync_ref_data *refdata;
388 	u8 *time_txf_buf = util_timesynch.recv_buffer;
389 
390 	/*
391 	 * Drain the ring buffer and use the last packet to update
392 	 * host_ts
393 	 */
394 	while (1) {
395 		int ret = vmbus_recvpacket(channel, time_txf_buf,
396 					   HV_HYP_PAGE_SIZE, &recvlen,
397 					   &requestid);
398 		if (ret) {
399 			pr_warn_once("TimeSync IC pkt recv failed (Err: %d)\n",
400 				     ret);
401 			break;
402 		}
403 
404 		if (!recvlen)
405 			break;
406 
407 		icmsghdrp = (struct icmsg_hdr *)&time_txf_buf[
408 				sizeof(struct vmbuspipe_hdr)];
409 
410 		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
411 			if (vmbus_prep_negotiate_resp(icmsghdrp, time_txf_buf,
412 						fw_versions, FW_VER_COUNT,
413 						ts_versions, TS_VER_COUNT,
414 						NULL, &ts_srv_version)) {
415 				pr_info("TimeSync IC version %d.%d\n",
416 					ts_srv_version >> 16,
417 					ts_srv_version & 0xFFFF);
418 			}
419 		} else {
420 			if (ts_srv_version > TS_VERSION_3) {
421 				refdata = (struct ictimesync_ref_data *)
422 					&time_txf_buf[
423 					sizeof(struct vmbuspipe_hdr) +
424 					sizeof(struct icmsg_hdr)];
425 
426 				adj_guesttime(refdata->parenttime,
427 						refdata->vmreferencetime,
428 						refdata->flags);
429 			} else {
430 				timedatap = (struct ictimesync_data *)
431 					&time_txf_buf[
432 					sizeof(struct vmbuspipe_hdr) +
433 					sizeof(struct icmsg_hdr)];
434 				adj_guesttime(timedatap->parenttime,
435 					      hv_read_reference_counter(),
436 					      timedatap->flags);
437 			}
438 		}
439 
440 		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
441 			| ICMSGHDRFLAG_RESPONSE;
442 
443 		vmbus_sendpacket(channel, time_txf_buf,
444 				recvlen, requestid,
445 				VM_PKT_DATA_INBAND, 0);
446 	}
447 }
448 
449 /*
450  * Heartbeat functionality.
451  * Every two seconds, Hyper-V send us a heartbeat request message.
452  * we respond to this message, and Hyper-V knows we are alive.
453  */
454 static void heartbeat_onchannelcallback(void *context)
455 {
456 	struct vmbus_channel *channel = context;
457 	u32 recvlen;
458 	u64 requestid;
459 	struct icmsg_hdr *icmsghdrp;
460 	struct heartbeat_msg_data *heartbeat_msg;
461 	u8 *hbeat_txf_buf = util_heartbeat.recv_buffer;
462 
463 	while (1) {
464 
465 		vmbus_recvpacket(channel, hbeat_txf_buf,
466 				 HV_HYP_PAGE_SIZE, &recvlen, &requestid);
467 
468 		if (!recvlen)
469 			break;
470 
471 		icmsghdrp = (struct icmsg_hdr *)&hbeat_txf_buf[
472 				sizeof(struct vmbuspipe_hdr)];
473 
474 		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
475 			if (vmbus_prep_negotiate_resp(icmsghdrp,
476 					hbeat_txf_buf,
477 					fw_versions, FW_VER_COUNT,
478 					hb_versions, HB_VER_COUNT,
479 					NULL, &hb_srv_version)) {
480 
481 				pr_info("Heartbeat IC version %d.%d\n",
482 					hb_srv_version >> 16,
483 					hb_srv_version & 0xFFFF);
484 			}
485 		} else {
486 			heartbeat_msg =
487 				(struct heartbeat_msg_data *)&hbeat_txf_buf[
488 					sizeof(struct vmbuspipe_hdr) +
489 					sizeof(struct icmsg_hdr)];
490 
491 			heartbeat_msg->seq_num += 1;
492 		}
493 
494 		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
495 			| ICMSGHDRFLAG_RESPONSE;
496 
497 		vmbus_sendpacket(channel, hbeat_txf_buf,
498 				       recvlen, requestid,
499 				       VM_PKT_DATA_INBAND, 0);
500 	}
501 }
502 
503 #define HV_UTIL_RING_SEND_SIZE VMBUS_RING_SIZE(3 * HV_HYP_PAGE_SIZE)
504 #define HV_UTIL_RING_RECV_SIZE VMBUS_RING_SIZE(3 * HV_HYP_PAGE_SIZE)
505 
506 static int util_probe(struct hv_device *dev,
507 			const struct hv_vmbus_device_id *dev_id)
508 {
509 	struct hv_util_service *srv =
510 		(struct hv_util_service *)dev_id->driver_data;
511 	int ret;
512 
513 	srv->recv_buffer = kmalloc(HV_HYP_PAGE_SIZE * 4, GFP_KERNEL);
514 	if (!srv->recv_buffer)
515 		return -ENOMEM;
516 	srv->channel = dev->channel;
517 	if (srv->util_init) {
518 		ret = srv->util_init(srv);
519 		if (ret) {
520 			ret = -ENODEV;
521 			goto error1;
522 		}
523 	}
524 
525 	/*
526 	 * The set of services managed by the util driver are not performance
527 	 * critical and do not need batched reading. Furthermore, some services
528 	 * such as KVP can only handle one message from the host at a time.
529 	 * Turn off batched reading for all util drivers before we open the
530 	 * channel.
531 	 */
532 	set_channel_read_mode(dev->channel, HV_CALL_DIRECT);
533 
534 	hv_set_drvdata(dev, srv);
535 
536 	ret = vmbus_open(dev->channel, HV_UTIL_RING_SEND_SIZE,
537 			 HV_UTIL_RING_RECV_SIZE, NULL, 0, srv->util_cb,
538 			 dev->channel);
539 	if (ret)
540 		goto error;
541 
542 	return 0;
543 
544 error:
545 	if (srv->util_deinit)
546 		srv->util_deinit();
547 error1:
548 	kfree(srv->recv_buffer);
549 	return ret;
550 }
551 
552 static int util_remove(struct hv_device *dev)
553 {
554 	struct hv_util_service *srv = hv_get_drvdata(dev);
555 
556 	if (srv->util_deinit)
557 		srv->util_deinit();
558 	vmbus_close(dev->channel);
559 	kfree(srv->recv_buffer);
560 
561 	return 0;
562 }
563 
564 /*
565  * When we're in util_suspend(), all the userspace processes have been frozen
566  * (refer to hibernate() -> freeze_processes()). The userspace is thawed only
567  * after the whole resume procedure, including util_resume(), finishes.
568  */
569 static int util_suspend(struct hv_device *dev)
570 {
571 	struct hv_util_service *srv = hv_get_drvdata(dev);
572 	int ret = 0;
573 
574 	if (srv->util_pre_suspend) {
575 		ret = srv->util_pre_suspend();
576 		if (ret)
577 			return ret;
578 	}
579 
580 	vmbus_close(dev->channel);
581 
582 	return 0;
583 }
584 
585 static int util_resume(struct hv_device *dev)
586 {
587 	struct hv_util_service *srv = hv_get_drvdata(dev);
588 	int ret = 0;
589 
590 	if (srv->util_pre_resume) {
591 		ret = srv->util_pre_resume();
592 		if (ret)
593 			return ret;
594 	}
595 
596 	ret = vmbus_open(dev->channel, HV_UTIL_RING_SEND_SIZE,
597 			 HV_UTIL_RING_RECV_SIZE, NULL, 0, srv->util_cb,
598 			 dev->channel);
599 	return ret;
600 }
601 
602 static const struct hv_vmbus_device_id id_table[] = {
603 	/* Shutdown guid */
604 	{ HV_SHUTDOWN_GUID,
605 	  .driver_data = (unsigned long)&util_shutdown
606 	},
607 	/* Time synch guid */
608 	{ HV_TS_GUID,
609 	  .driver_data = (unsigned long)&util_timesynch
610 	},
611 	/* Heartbeat guid */
612 	{ HV_HEART_BEAT_GUID,
613 	  .driver_data = (unsigned long)&util_heartbeat
614 	},
615 	/* KVP guid */
616 	{ HV_KVP_GUID,
617 	  .driver_data = (unsigned long)&util_kvp
618 	},
619 	/* VSS GUID */
620 	{ HV_VSS_GUID,
621 	  .driver_data = (unsigned long)&util_vss
622 	},
623 	/* File copy GUID */
624 	{ HV_FCOPY_GUID,
625 	  .driver_data = (unsigned long)&util_fcopy
626 	},
627 	{ },
628 };
629 
630 MODULE_DEVICE_TABLE(vmbus, id_table);
631 
632 /* The one and only one */
633 static  struct hv_driver util_drv = {
634 	.name = "hv_utils",
635 	.id_table = id_table,
636 	.probe =  util_probe,
637 	.remove =  util_remove,
638 	.suspend = util_suspend,
639 	.resume =  util_resume,
640 	.driver = {
641 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
642 	},
643 };
644 
645 static int hv_ptp_enable(struct ptp_clock_info *info,
646 			 struct ptp_clock_request *request, int on)
647 {
648 	return -EOPNOTSUPP;
649 }
650 
651 static int hv_ptp_settime(struct ptp_clock_info *p, const struct timespec64 *ts)
652 {
653 	return -EOPNOTSUPP;
654 }
655 
656 static int hv_ptp_adjfreq(struct ptp_clock_info *ptp, s32 delta)
657 {
658 	return -EOPNOTSUPP;
659 }
660 static int hv_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
661 {
662 	return -EOPNOTSUPP;
663 }
664 
665 static int hv_ptp_gettime(struct ptp_clock_info *info, struct timespec64 *ts)
666 {
667 	return hv_get_adj_host_time(ts);
668 }
669 
670 static struct ptp_clock_info ptp_hyperv_info = {
671 	.name		= "hyperv",
672 	.enable         = hv_ptp_enable,
673 	.adjtime        = hv_ptp_adjtime,
674 	.adjfreq        = hv_ptp_adjfreq,
675 	.gettime64      = hv_ptp_gettime,
676 	.settime64      = hv_ptp_settime,
677 	.owner		= THIS_MODULE,
678 };
679 
680 static struct ptp_clock *hv_ptp_clock;
681 
682 static int hv_timesync_init(struct hv_util_service *srv)
683 {
684 	/* TimeSync requires Hyper-V clocksource. */
685 	if (!hv_read_reference_counter)
686 		return -ENODEV;
687 
688 	spin_lock_init(&host_ts.lock);
689 
690 	INIT_WORK(&adj_time_work, hv_set_host_time);
691 
692 	/*
693 	 * ptp_clock_register() returns NULL when CONFIG_PTP_1588_CLOCK is
694 	 * disabled but the driver is still useful without the PTP device
695 	 * as it still handles the ICTIMESYNCFLAG_SYNC case.
696 	 */
697 	hv_ptp_clock = ptp_clock_register(&ptp_hyperv_info, NULL);
698 	if (IS_ERR_OR_NULL(hv_ptp_clock)) {
699 		pr_err("cannot register PTP clock: %ld\n",
700 		       PTR_ERR(hv_ptp_clock));
701 		hv_ptp_clock = NULL;
702 	}
703 
704 	return 0;
705 }
706 
707 static void hv_timesync_cancel_work(void)
708 {
709 	cancel_work_sync(&adj_time_work);
710 }
711 
712 static int hv_timesync_pre_suspend(void)
713 {
714 	hv_timesync_cancel_work();
715 	return 0;
716 }
717 
718 static void hv_timesync_deinit(void)
719 {
720 	if (hv_ptp_clock)
721 		ptp_clock_unregister(hv_ptp_clock);
722 
723 	hv_timesync_cancel_work();
724 }
725 
726 static int __init init_hyperv_utils(void)
727 {
728 	pr_info("Registering HyperV Utility Driver\n");
729 
730 	return vmbus_driver_register(&util_drv);
731 }
732 
733 static void exit_hyperv_utils(void)
734 {
735 	pr_info("De-Registered HyperV Utility Driver\n");
736 
737 	vmbus_driver_unregister(&util_drv);
738 }
739 
740 module_init(init_hyperv_utils);
741 module_exit(exit_hyperv_utils);
742 
743 MODULE_DESCRIPTION("Hyper-V Utilities");
744 MODULE_LICENSE("GPL");
745