summaryrefslogtreecommitdiffstats
path: root/drivers/thunderbolt/tb.c
blob: 49589b38ff12f4dd8357b61a28c7a962bfeab7b3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
// SPDX-License-Identifier: GPL-2.0
/*
 * Thunderbolt driver - bus logic (NHI independent)
 *
 * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
 * Copyright (C) 2019, Intel Corporation
 */

#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/platform_data/x86/apple.h>

#include "tb.h"
#include "tb_regs.h"
#include "tunnel.h"

/**
 * struct tb_cm - Simple Thunderbolt connection manager
 * @tunnel_list: List of active tunnels
 * @hotplug_active: tb_handle_hotplug will stop progressing plug
 *		    events and exit if this is not set (it needs to
 *		    acquire the lock one more time). Used to drain wq
 *		    after cfg has been paused.
 */
struct tb_cm {
	struct list_head tunnel_list;
	bool hotplug_active;
};

struct tb_hotplug_event {
	struct work_struct work;
	struct tb *tb;
	u64 route;
	u8 port;
	bool unplug;
};

static void tb_handle_hotplug(struct work_struct *work);

static void tb_queue_hotplug(struct tb *tb, u64 route, u8 port, bool unplug)
{
	struct tb_hotplug_event *ev;

	ev = kmalloc(sizeof(*ev), GFP_KERNEL);
	if (!ev)
		return;

	ev->tb = tb;
	ev->route = route;
	ev->port = port;
	ev->unplug = unplug;
	INIT_WORK(&ev->work, tb_handle_hotplug);
	queue_work(tb->wq, &ev->work);
}

/* enumeration & hot plug handling */

static void tb_discover_tunnels(struct tb_switch *sw)
{
	struct tb *tb = sw->tb;
	struct tb_cm *tcm = tb_priv(tb);
	struct tb_port *port;

	tb_switch_for_each_port(sw, port) {
		struct tb_tunnel *tunnel = NULL;

		switch (port->config.type) {
		case TB_TYPE_DP_HDMI_IN:
			tunnel = tb_tunnel_discover_dp(tb, port);
			break;

		case TB_TYPE_PCIE_DOWN:
			tunnel = tb_tunnel_discover_pci(tb, port);
			break;

		default:
			break;
		}

		if (!tunnel)
			continue;

		if (tb_tunnel_is_pci(tunnel)) {
			struct tb_switch *parent = tunnel->dst_port->sw;

			while (parent != tunnel->src_port->sw) {
				parent->boot = true;
				parent = tb_switch_parent(parent);
			}
		}

		list_add_tail(&tunnel->list, &tcm->tunnel_list);
	}

	tb_switch_for_each_port(sw, port) {
		if (tb_port_has_remote(port))
			tb_discover_tunnels(port->remote->sw);
	}
}

static void tb_scan_xdomain(struct tb_port *port)
{
	struct tb_switch *sw = port->sw;
	struct tb *tb = sw->tb;
	struct tb_xdomain *xd;
	u64 route;

	route = tb_downstream_route(port);
	xd = tb_xdomain_find_by_route(tb, route);
	if (xd) {
		tb_xdomain_put(xd);
		return;
	}

	xd = tb_xdomain_alloc(tb, &sw->dev, route, tb->root_switch->uuid,
			      NULL);
	if (xd) {
		tb_port_at(route, sw)->xdomain = xd;
		tb_xdomain_add(xd);
	}
}

static void tb_scan_port(struct tb_port *port);

/**
 * tb_scan_switch() - scan for and initialize downstream switches
 */
static void tb_scan_switch(struct tb_switch *sw)
{
	struct tb_port *port;

	tb_switch_for_each_port(sw, port)
		tb_scan_port(port);
}

/**
 * tb_scan_port() - check for and initialize switches below port
 */
static void tb_scan_port(struct tb_port *port)
{
	struct tb_cm *tcm = tb_priv(port->sw->tb);
	struct tb_port *upstream_port;
	struct tb_switch *sw;

	if (tb_is_upstream_port(port))
		return;

	if (tb_port_is_dpout(port) && tb_dp_port_hpd_is_active(port) == 1 &&
	    !tb_dp_port_is_enabled(port)) {
		tb_port_dbg(port, "DP adapter HPD set, queuing hotplug\n");
		tb_queue_hotplug(port->sw->tb, tb_route(port->sw), port->port,
				 false);
		return;
	}

	if (port->config.type != TB_TYPE_PORT)
		return;
	if (port->dual_link_port && port->link_nr)
		return; /*
			 * Downstream switch is reachable through two ports.
			 * Only scan on the primary port (link_nr == 0).
			 */
	if (tb_wait_for_port(port, false) <= 0)
		return;
	if (port->remote) {
		tb_port_dbg(port, "port already has a remote\n");
		return;
	}
	sw = tb_switch_alloc(port->sw->tb, &port->sw->dev,
			     tb_downstream_route(port));
	if (IS_ERR(sw)) {
		/*
		 * If there is an error accessing the connected switch
		 * it may be connected to another domain. Also we allow
		 * the other domain to be connected to a max depth switch.
		 */
		if (PTR_ERR(sw) == -EIO || PTR_ERR(sw) == -EADDRNOTAVAIL)
			tb_scan_xdomain(port);
		return;
	}

	if (tb_switch_configure(sw)) {
		tb_switch_put(sw);
		return;
	}

	/*
	 * If there was previously another domain connected remove it
	 * first.
	 */
	if (port->xdomain) {
		tb_xdomain_remove(port->xdomain);
		port->xdomain = NULL;
	}

	/*
	 * Do not send uevents until we have discovered all existing
	 * tunnels and know which switches were authorized already by
	 * the boot firmware.
	 */
	if (!tcm->hotplug_active)
		dev_set_uevent_suppress(&sw->dev, true);

	if (tb_switch_add(sw)) {
		tb_switch_put(sw);
		return;
	}

	/* Link the switches using both links if available */
	upstream_port = tb_upstream_port(sw);
	port->remote = upstream_port;
	upstream_port->remote = port;
	if (port->dual_link_port && upstream_port->dual_link_port) {
		port->dual_link_port->remote = upstream_port->dual_link_port;
		upstream_port->dual_link_port->remote = port->dual_link_port;
	}

	tb_scan_switch(sw);
}

static int tb_free_tunnel(struct tb *tb, enum tb_tunnel_type type,
			  struct tb_port *src_port, struct tb_port *dst_port)
{
	struct tb_cm *tcm = tb_priv(tb);
	struct tb_tunnel *tunnel;

	list_for_each_entry(tunnel, &tcm->tunnel_list, list) {
		if (tunnel->type == type &&
		    ((src_port && src_port == tunnel->src_port) ||
		     (dst_port && dst_port == tunnel->dst_port))) {
			tb_tunnel_deactivate(tunnel);
			list_del(&tunnel->list);
			tb_tunnel_free(tunnel);
			return 0;
		}
	}

	return -ENODEV;
}

/**
 * tb_free_invalid_tunnels() - destroy tunnels of devices that have gone away
 */
static void tb_free_invalid_tunnels(struct tb *tb)
{
	struct tb_cm *tcm = tb_priv(tb);
	struct tb_tunnel *tunnel;
	struct tb_tunnel *n;

	list_for_each_entry_safe(tunnel, n, &tcm->tunnel_list, list) {
		if (tb_tunnel_is_invalid(tunnel)) {
			tb_tunnel_deactivate(tunnel);
			list_del(&tunnel->list);
			tb_tunnel_free(tunnel);
		}
	}
}

/**
 * tb_free_unplugged_children() - traverse hierarchy and free unplugged switches
 */
static void tb_free_unplugged_children(struct tb_switch *sw)
{
	struct tb_port *port;

	tb_switch_for_each_port(sw, port) {
		if (!tb_port_has_remote(port))
			continue;

		if (port->remote->sw->is_unplugged) {
			tb_switch_remove(port->remote->sw);
			port->remote = NULL;
			if (port->dual_link_port)
				port->dual_link_port->remote = NULL;
		} else {
			tb_free_unplugged_children(port->remote->sw);
		}
	}
}

/**
 * tb_find_port() - return the first port of @type on @sw or NULL
 * @sw: Switch to find the port from
 * @type: Port type to look for
 */
static struct tb_port *tb_find_port(struct tb_switch *sw,
				    enum tb_port_type type)
{
	struct tb_port *port;

	tb_switch_for_each_port(sw, port) {
		if (port->config.type == type)
			return port;
	}

	return NULL;
}

/**
 * tb_find_unused_port() - return the first inactive port on @sw
 * @sw: Switch to find the port on
 * @type: Port type to look for
 */
static struct tb_port *tb_find_unused_port(struct tb_switch *sw,
					   enum tb_port_type type)
{
	struct tb_port *port;

	tb_switch_for_each_port(sw, port) {
		if (tb_is_upstream_port(port))
			continue;
		if (port->config.type != type)
			continue;
		if (port->cap_adap)
			continue;
		if (tb_port_is_enabled(port))
			continue;
		return port;
	}
	return NULL;
}

static struct tb_port *tb_find_pcie_down(struct tb_switch *sw,
					 const struct tb_port *port)
{
	/*
	 * To keep plugging devices consistently in the same PCIe
	 * hierarchy, do mapping here for root switch downstream PCIe
	 * ports.
	 */
	if (!tb_route(sw)) {
		int phy_port = tb_phy_port_from_link(port->port);
		int index;

		/*
		 * Hard-coded Thunderbolt port to PCIe down port mapping
		 * per controller.
		 */
		if (tb_switch_is_cr(sw))
			index = !phy_port ? 6 : 7;
		else if (tb_switch_is_fr(sw))
			index = !phy_port ? 6 : 8;
		else
			goto out;

		/* Validate the hard-coding */
		if (WARN_ON(index > sw->config.max_port_number))
			goto out;
		if (WARN_ON(!tb_port_is_pcie_down(&sw->ports[index])))
			goto out;
		if (WARN_ON(tb_pci_port_is_enabled(&sw->ports[index])))
			goto out;

		return &sw->ports[index];
	}

out:
	return tb_find_unused_port(sw, TB_TYPE_PCIE_DOWN);
}

static int tb_tunnel_dp(struct tb *tb, struct tb_port *out)
{
	struct tb_cm *tcm = tb_priv(tb);
	struct tb_switch *sw = out->sw;
	struct tb_tunnel *tunnel;
	struct tb_port *in;

	if (tb_port_is_enabled(out))
		return 0;

	do {
		sw = tb_to_switch(sw->dev.parent);
		if (!sw)
			return 0;
		in = tb_find_unused_port(sw, TB_TYPE_DP_HDMI_IN);
	} while (!in);

	tunnel = tb_tunnel_alloc_dp(tb, in, out);
	if (!tunnel) {
		tb_port_dbg(out, "DP tunnel allocation failed\n");
		return -ENOMEM;
	}

	if (tb_tunnel_activate(tunnel)) {
		tb_port_info(out, "DP tunnel activation failed, aborting\n");
		tb_tunnel_free(tunnel);
		return -EIO;
	}

	list_add_tail(&tunnel->list, &tcm->tunnel_list);
	return 0;
}

static void tb_teardown_dp(struct tb *tb, struct tb_port *out)
{
	tb_free_tunnel(tb, TB_TUNNEL_DP, NULL, out);
}

static int tb_tunnel_pci(struct tb *tb, struct tb_switch *sw)
{
	struct tb_port *up, *down, *port;
	struct tb_cm *tcm = tb_priv(tb);
	struct tb_switch *parent_sw;
	struct tb_tunnel *tunnel;

	up = tb_find_port(sw, TB_TYPE_PCIE_UP);
	if (!up)
		return 0;

	/*
	 * Look up available down port. Since we are chaining it should
	 * be found right above this switch.
	 */
	parent_sw = tb_to_switch(sw->dev.parent);
	port = tb_port_at(tb_route(sw), parent_sw);
	down = tb_find_pcie_down(parent_sw, port);
	if (!down)
		return 0;

	tunnel = tb_tunnel_alloc_pci(tb, up, down);
	if (!tunnel)
		return -ENOMEM;

	if (tb_tunnel_activate(tunnel)) {
		tb_port_info(up,
			     "PCIe tunnel activation failed, aborting\n");
		tb_tunnel_free(tunnel);
		return -EIO;
	}

	list_add_tail(&tunnel->list, &tcm->tunnel_list);
	return 0;
}

static int tb_approve_xdomain_paths(struct tb *tb, struct tb_xdomain *xd)
{
	struct tb_cm *tcm = tb_priv(tb);
	struct tb_port *nhi_port, *dst_port;
	struct tb_tunnel *tunnel;
	struct tb_switch *sw;

	sw = tb_to_switch(xd->dev.parent);
	dst_port = tb_port_at(xd->route, sw);
	nhi_port = tb_find_port(tb->root_switch, TB_TYPE_NHI);

	mutex_lock(&tb->lock);
	tunnel = tb_tunnel_alloc_dma(tb, nhi_port, dst_port, xd->transmit_ring,
				     xd->transmit_path, xd->receive_ring,
				     xd->receive_path);
	if (!tunnel) {
		mutex_unlock(&tb->lock);
		return -ENOMEM;
	}

	if (tb_tunnel_activate(tunnel)) {
		tb_port_info(nhi_port,
			     "DMA tunnel activation failed, aborting\n");
		tb_tunnel_free(tunnel);
		mutex_unlock(&tb->lock);
		return -EIO;
	}

	list_add_tail(&tunnel->list, &tcm->tunnel_list);
	mutex_unlock(&tb->lock);
	return 0;
}

static void __tb_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd)
{
	struct tb_port *dst_port;
	struct tb_switch *sw;

	sw = tb_to_switch(xd->dev.parent);
	dst_port = tb_port_at(xd->route, sw);

	/*
	 * It is possible that the tunnel was already teared down (in
	 * case of cable disconnect) so it is fine if we cannot find it
	 * here anymore.
	 */
	tb_free_tunnel(tb, TB_TUNNEL_DMA, NULL, dst_port);
}

static int tb_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd)
{
	if (!xd->is_unplugged) {
		mutex_lock(&tb->lock);
		__tb_disconnect_xdomain_paths(tb, xd);
		mutex_unlock(&tb->lock);
	}
	return 0;
}

/* hotplug handling */

/**
 * tb_handle_hotplug() - handle hotplug event
 *
 * Executes on tb->wq.
 */
static void tb_handle_hotplug(struct work_struct *work)
{
	struct tb_hotplug_event *ev = container_of(work, typeof(*ev), work);
	struct tb *tb = ev->tb;
	struct tb_cm *tcm = tb_priv(tb);
	struct tb_switch *sw;
	struct tb_port *port;
	mutex_lock(&tb->lock);
	if (!tcm->hotplug_active)
		goto out; /* during init, suspend or shutdown */

	sw = tb_switch_find_by_route(tb, ev->route);
	if (!sw) {
		tb_warn(tb,
			"hotplug event from non existent switch %llx:%x (unplug: %d)\n",
			ev->route, ev->port, ev->unplug);
		goto out;
	}
	if (ev->port > sw->config.max_port_number) {
		tb_warn(tb,
			"hotplug event from non existent port %llx:%x (unplug: %d)\n",
			ev->route, ev->port, ev->unplug);
		goto put_sw;
	}
	port = &sw->ports[ev->port];
	if (tb_is_upstream_port(port)) {
		tb_dbg(tb, "hotplug event for upstream port %llx:%x (unplug: %d)\n",
		       ev->route, ev->port, ev->unplug);
		goto put_sw;
	}
	if (ev->unplug) {
		if (tb_port_has_remote(port)) {
			tb_port_dbg(port, "switch unplugged\n");
			tb_sw_set_unplugged(port->remote->sw);
			tb_free_invalid_tunnels(tb);
			tb_switch_remove(port->remote->sw);
			port->remote = NULL;
			if (port->dual_link_port)
				port->dual_link_port->remote = NULL;
		} else if (port->xdomain) {
			struct tb_xdomain *xd = tb_xdomain_get(port->xdomain);

			tb_port_dbg(port, "xdomain unplugged\n");
			/*
			 * Service drivers are unbound during
			 * tb_xdomain_remove() so setting XDomain as
			 * unplugged here prevents deadlock if they call
			 * tb_xdomain_disable_paths(). We will tear down
			 * the path below.
			 */
			xd->is_unplugged = true;
			tb_xdomain_remove(xd);
			port->xdomain = NULL;
			__tb_disconnect_xdomain_paths(tb, xd);
			tb_xdomain_put(xd);
		} else if (tb_port_is_dpout(port)) {
			tb_teardown_dp(tb, port);
		} else {
			tb_port_dbg(port,
				   "got unplug event for disconnected port, ignoring\n");
		}
	} else if (port->remote) {
		tb_port_dbg(port, "got plug event for connected port, ignoring\n");
	} else {
		if (tb_port_is_null(port)) {
			tb_port_dbg(port, "hotplug: scanning\n");
			tb_scan_port(port);
			if (!port->remote)
				tb_port_dbg(port, "hotplug: no switch found\n");
		} else if (tb_port_is_dpout(port)) {
			tb_tunnel_dp(tb, port);
		}
	}

put_sw:
	tb_switch_put(sw);
out:
	mutex_unlock(&tb->lock);
	kfree(ev);
}

/**
 * tb_schedule_hotplug_handler() - callback function for the control channel
 *
 * Delegates to tb_handle_hotplug.
 */
static void tb_handle_event(struct tb *tb, enum tb_cfg_pkg_type type,
			    const void *buf, size_t size)
{
	const struct cfg_event_pkg *pkg = buf;
	u64 route;

	if (type != TB_CFG_PKG_EVENT) {
		tb_warn(tb, "unexpected event %#x, ignoring\n", type);
		return;
	}

	route = tb_cfg_get_route(&pkg->header);

	if (tb_cfg_error(tb->ctl, route, pkg->port,
			 TB_CFG_ERROR_ACK_PLUG_EVENT)) {
		tb_warn(tb, "could not ack plug event on %llx:%x\n", route,
			pkg->port);
	}

	tb_queue_hotplug(tb, route, pkg->port, pkg->unplug);
}

static void tb_stop(struct tb *tb)
{
	struct tb_cm *tcm = tb_priv(tb);
	struct tb_tunnel *tunnel;
	struct tb_tunnel *n;

	/* tunnels are only present after everything has been initialized */
	list_for_each_entry_safe(tunnel, n, &tcm->tunnel_list, list) {
		/*
		 * DMA tunnels require the driver to be functional so we
		 * tear them down. Other protocol tunnels can be left
		 * intact.
		 */
		if (tb_tunnel_is_dma(tunnel))
			tb_tunnel_deactivate(tunnel);
		tb_tunnel_free(tunnel);
	}
	tb_switch_remove(tb->root_switch);
	tcm->hotplug_active = false; /* signal tb_handle_hotplug to quit */
}

static int tb_scan_finalize_switch(struct device *dev, void *data)
{
	if (tb_is_switch(dev)) {
		struct tb_switch *sw = tb_to_switch(dev);

		/*
		 * If we found that the switch was already setup by the
		 * boot firmware, mark it as authorized now before we
		 * send uevent to userspace.
		 */
		if (sw->boot)
			sw->authorized = 1;

		dev_set_uevent_suppress(dev, false);
		kobject_uevent(&dev->kobj, KOBJ_ADD);
		device_for_each_child(dev, NULL, tb_scan_finalize_switch);
	}

	return 0;
}

static int tb_start(struct tb *tb)
{
	struct tb_cm *tcm = tb_priv(tb);
	int ret;

	tb->root_switch = tb_switch_alloc(tb, &tb->dev, 0);
	if (IS_ERR(tb->root_switch))
		return PTR_ERR(tb->root_switch);

	/*
	 * ICM firmware upgrade needs running firmware and in native
	 * mode that is not available so disable firmware upgrade of the
	 * root switch.
	 */
	tb->root_switch->no_nvm_upgrade = true;

	ret = tb_switch_configure(tb->root_switch);
	if (ret) {
		tb_switch_put(tb->root_switch);
		return ret;
	}

	/* Announce the switch to the world */
	ret = tb_switch_add(tb->root_switch);
	if (ret) {
		tb_switch_put(tb->root_switch);
		return ret;
	}

	/* Full scan to discover devices added before the driver was loaded. */
	tb_scan_switch(tb->root_switch);
	/* Find out tunnels created by the boot firmware */
	tb_discover_tunnels(tb->root_switch);
	/* Make the discovered switches available to the userspace */
	device_for_each_child(&tb->root_switch->dev, NULL,
			      tb_scan_finalize_switch);

	/* Allow tb_handle_hotplug to progress events */
	tcm->hotplug_active = true;
	return 0;
}

static int tb_suspend_noirq(struct tb *tb)
{
	struct tb_cm *tcm = tb_priv(tb);

	tb_dbg(tb, "suspending...\n");
	tb_switch_suspend(tb->root_switch);
	tcm->hotplug_active = false; /* signal tb_handle_hotplug to quit */
	tb_dbg(tb, "suspend finished\n");

	return 0;
}

static int tb_resume_noirq(struct tb *tb)
{
	struct tb_cm *tcm = tb_priv(tb);
	struct tb_tunnel *tunnel, *n;

	tb_dbg(tb, "resuming...\n");

	/* remove any pci devices the firmware might have setup */
	tb_switch_reset(tb, 0);

	tb_switch_resume(tb->root_switch);
	tb_free_invalid_tunnels(tb);
	tb_free_unplugged_children(tb->root_switch);
	list_for_each_entry_safe(tunnel, n, &tcm->tunnel_list, list)
		tb_tunnel_restart(tunnel);
	if (!list_empty(&tcm->tunnel_list)) {
		/*
		 * the pcie links need some time to get going.
		 * 100ms works for me...
		 */
		tb_dbg(tb, "tunnels restarted, sleeping for 100ms\n");
		msleep(100);
	}
	 /* Allow tb_handle_hotplug to progress events */
	tcm->hotplug_active = true;
	tb_dbg(tb, "resume finished\n");

	return 0;
}

static int tb_free_unplugged_xdomains(struct tb_switch *sw)
{
	struct tb_port *port;
	int ret = 0;

	tb_switch_for_each_port(sw, port) {
		if (tb_is_upstream_port(port))
			continue;
		if (port->xdomain && port->xdomain->is_unplugged) {
			tb_xdomain_remove(port->xdomain);
			port->xdomain = NULL;
			ret++;
		} else if (port->remote) {
			ret += tb_free_unplugged_xdomains(port->remote->sw);
		}
	}

	return ret;
}

static void tb_complete(struct tb *tb)
{
	/*
	 * Release any unplugged XDomains and if there is a case where
	 * another domain is swapped in place of unplugged XDomain we
	 * need to run another rescan.
	 */
	mutex_lock(&tb->lock);
	if (tb_free_unplugged_xdomains(tb->root_switch))
		tb_scan_switch(tb->root_switch);
	mutex_unlock(&tb->lock);
}

static const struct tb_cm_ops tb_cm_ops = {
	.start = tb_start,
	.stop = tb_stop,
	.suspend_noirq = tb_suspend_noirq,
	.resume_noirq = tb_resume_noirq,
	.complete = tb_complete,
	.handle_event = tb_handle_event,
	.approve_switch = tb_tunnel_pci,
	.approve_xdomain_paths = tb_approve_xdomain_paths,
	.disconnect_xdomain_paths = tb_disconnect_xdomain_paths,
};

struct tb *tb_probe(struct tb_nhi *nhi)
{
	struct tb_cm *tcm;
	struct tb *tb;

	if (!x86_apple_machine)
		return NULL;

	tb = tb_domain_alloc(nhi, sizeof(*tcm));
	if (!tb)
		return NULL;

	tb->security_level = TB_SECURITY_USER;
	tb->cm_ops = &tb_cm_ops;

	tcm = tb_priv(tb);
	INIT_LIST_HEAD(&tcm->tunnel_list);

	return tb;
}