xref: /openbmc/linux/drivers/thunderbolt/switch.c (revision d2c43ff1)
1 /*
2  * Thunderbolt Cactus Ridge driver - switch/port utility functions
3  *
4  * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
5  */
6 
7 #include <linux/delay.h>
8 #include <linux/idr.h>
9 #include <linux/nvmem-provider.h>
10 #include <linux/sizes.h>
11 #include <linux/slab.h>
12 #include <linux/vmalloc.h>
13 
14 #include "tb.h"
15 
16 /* Switch authorization from userspace is serialized by this lock */
17 static DEFINE_MUTEX(switch_lock);
18 
19 /* Switch NVM support */
20 
21 #define NVM_DEVID		0x05
22 #define NVM_VERSION		0x08
23 #define NVM_CSS			0x10
24 #define NVM_FLASH_SIZE		0x45
25 
26 #define NVM_MIN_SIZE		SZ_32K
27 #define NVM_MAX_SIZE		SZ_512K
28 
29 static DEFINE_IDA(nvm_ida);
30 
31 struct nvm_auth_status {
32 	struct list_head list;
33 	uuid_t uuid;
34 	u32 status;
35 };
36 
37 /*
38  * Hold NVM authentication failure status per switch This information
39  * needs to stay around even when the switch gets power cycled so we
40  * keep it separately.
41  */
42 static LIST_HEAD(nvm_auth_status_cache);
43 static DEFINE_MUTEX(nvm_auth_status_lock);
44 
45 static struct nvm_auth_status *__nvm_get_auth_status(const struct tb_switch *sw)
46 {
47 	struct nvm_auth_status *st;
48 
49 	list_for_each_entry(st, &nvm_auth_status_cache, list) {
50 		if (uuid_equal(&st->uuid, sw->uuid))
51 			return st;
52 	}
53 
54 	return NULL;
55 }
56 
57 static void nvm_get_auth_status(const struct tb_switch *sw, u32 *status)
58 {
59 	struct nvm_auth_status *st;
60 
61 	mutex_lock(&nvm_auth_status_lock);
62 	st = __nvm_get_auth_status(sw);
63 	mutex_unlock(&nvm_auth_status_lock);
64 
65 	*status = st ? st->status : 0;
66 }
67 
68 static void nvm_set_auth_status(const struct tb_switch *sw, u32 status)
69 {
70 	struct nvm_auth_status *st;
71 
72 	if (WARN_ON(!sw->uuid))
73 		return;
74 
75 	mutex_lock(&nvm_auth_status_lock);
76 	st = __nvm_get_auth_status(sw);
77 
78 	if (!st) {
79 		st = kzalloc(sizeof(*st), GFP_KERNEL);
80 		if (!st)
81 			goto unlock;
82 
83 		memcpy(&st->uuid, sw->uuid, sizeof(st->uuid));
84 		INIT_LIST_HEAD(&st->list);
85 		list_add_tail(&st->list, &nvm_auth_status_cache);
86 	}
87 
88 	st->status = status;
89 unlock:
90 	mutex_unlock(&nvm_auth_status_lock);
91 }
92 
93 static void nvm_clear_auth_status(const struct tb_switch *sw)
94 {
95 	struct nvm_auth_status *st;
96 
97 	mutex_lock(&nvm_auth_status_lock);
98 	st = __nvm_get_auth_status(sw);
99 	if (st) {
100 		list_del(&st->list);
101 		kfree(st);
102 	}
103 	mutex_unlock(&nvm_auth_status_lock);
104 }
105 
106 static int nvm_validate_and_write(struct tb_switch *sw)
107 {
108 	unsigned int image_size, hdr_size;
109 	const u8 *buf = sw->nvm->buf;
110 	u16 ds_size;
111 	int ret;
112 
113 	if (!buf)
114 		return -EINVAL;
115 
116 	image_size = sw->nvm->buf_data_size;
117 	if (image_size < NVM_MIN_SIZE || image_size > NVM_MAX_SIZE)
118 		return -EINVAL;
119 
120 	/*
121 	 * FARB pointer must point inside the image and must at least
122 	 * contain parts of the digital section we will be reading here.
123 	 */
124 	hdr_size = (*(u32 *)buf) & 0xffffff;
125 	if (hdr_size + NVM_DEVID + 2 >= image_size)
126 		return -EINVAL;
127 
128 	/* Digital section start should be aligned to 4k page */
129 	if (!IS_ALIGNED(hdr_size, SZ_4K))
130 		return -EINVAL;
131 
132 	/*
133 	 * Read digital section size and check that it also fits inside
134 	 * the image.
135 	 */
136 	ds_size = *(u16 *)(buf + hdr_size);
137 	if (ds_size >= image_size)
138 		return -EINVAL;
139 
140 	if (!sw->safe_mode) {
141 		u16 device_id;
142 
143 		/*
144 		 * Make sure the device ID in the image matches the one
145 		 * we read from the switch config space.
146 		 */
147 		device_id = *(u16 *)(buf + hdr_size + NVM_DEVID);
148 		if (device_id != sw->config.device_id)
149 			return -EINVAL;
150 
151 		if (sw->generation < 3) {
152 			/* Write CSS headers first */
153 			ret = dma_port_flash_write(sw->dma_port,
154 				DMA_PORT_CSS_ADDRESS, buf + NVM_CSS,
155 				DMA_PORT_CSS_MAX_SIZE);
156 			if (ret)
157 				return ret;
158 		}
159 
160 		/* Skip headers in the image */
161 		buf += hdr_size;
162 		image_size -= hdr_size;
163 	}
164 
165 	return dma_port_flash_write(sw->dma_port, 0, buf, image_size);
166 }
167 
168 static int nvm_authenticate_host(struct tb_switch *sw)
169 {
170 	int ret;
171 
172 	/*
173 	 * Root switch NVM upgrade requires that we disconnect the
174 	 * existing PCIe paths first (in case it is not in safe mode
175 	 * already).
176 	 */
177 	if (!sw->safe_mode) {
178 		ret = tb_domain_disconnect_pcie_paths(sw->tb);
179 		if (ret)
180 			return ret;
181 		/*
182 		 * The host controller goes away pretty soon after this if
183 		 * everything goes well so getting timeout is expected.
184 		 */
185 		ret = dma_port_flash_update_auth(sw->dma_port);
186 		return ret == -ETIMEDOUT ? 0 : ret;
187 	}
188 
189 	/*
190 	 * From safe mode we can get out by just power cycling the
191 	 * switch.
192 	 */
193 	dma_port_power_cycle(sw->dma_port);
194 	return 0;
195 }
196 
197 static int nvm_authenticate_device(struct tb_switch *sw)
198 {
199 	int ret, retries = 10;
200 
201 	ret = dma_port_flash_update_auth(sw->dma_port);
202 	if (ret && ret != -ETIMEDOUT)
203 		return ret;
204 
205 	/*
206 	 * Poll here for the authentication status. It takes some time
207 	 * for the device to respond (we get timeout for a while). Once
208 	 * we get response the device needs to be power cycled in order
209 	 * to the new NVM to be taken into use.
210 	 */
211 	do {
212 		u32 status;
213 
214 		ret = dma_port_flash_update_auth_status(sw->dma_port, &status);
215 		if (ret < 0 && ret != -ETIMEDOUT)
216 			return ret;
217 		if (ret > 0) {
218 			if (status) {
219 				tb_sw_warn(sw, "failed to authenticate NVM\n");
220 				nvm_set_auth_status(sw, status);
221 			}
222 
223 			tb_sw_info(sw, "power cycling the switch now\n");
224 			dma_port_power_cycle(sw->dma_port);
225 			return 0;
226 		}
227 
228 		msleep(500);
229 	} while (--retries);
230 
231 	return -ETIMEDOUT;
232 }
233 
234 static int tb_switch_nvm_read(void *priv, unsigned int offset, void *val,
235 			      size_t bytes)
236 {
237 	struct tb_switch *sw = priv;
238 
239 	return dma_port_flash_read(sw->dma_port, offset, val, bytes);
240 }
241 
242 static int tb_switch_nvm_write(void *priv, unsigned int offset, void *val,
243 			       size_t bytes)
244 {
245 	struct tb_switch *sw = priv;
246 	int ret = 0;
247 
248 	if (mutex_lock_interruptible(&switch_lock))
249 		return -ERESTARTSYS;
250 
251 	/*
252 	 * Since writing the NVM image might require some special steps,
253 	 * for example when CSS headers are written, we cache the image
254 	 * locally here and handle the special cases when the user asks
255 	 * us to authenticate the image.
256 	 */
257 	if (!sw->nvm->buf) {
258 		sw->nvm->buf = vmalloc(NVM_MAX_SIZE);
259 		if (!sw->nvm->buf) {
260 			ret = -ENOMEM;
261 			goto unlock;
262 		}
263 	}
264 
265 	sw->nvm->buf_data_size = offset + bytes;
266 	memcpy(sw->nvm->buf + offset, val, bytes);
267 
268 unlock:
269 	mutex_unlock(&switch_lock);
270 
271 	return ret;
272 }
273 
274 static struct nvmem_device *register_nvmem(struct tb_switch *sw, int id,
275 					   size_t size, bool active)
276 {
277 	struct nvmem_config config;
278 
279 	memset(&config, 0, sizeof(config));
280 
281 	if (active) {
282 		config.name = "nvm_active";
283 		config.reg_read = tb_switch_nvm_read;
284 		config.read_only = true;
285 	} else {
286 		config.name = "nvm_non_active";
287 		config.reg_write = tb_switch_nvm_write;
288 		config.root_only = true;
289 	}
290 
291 	config.id = id;
292 	config.stride = 4;
293 	config.word_size = 4;
294 	config.size = size;
295 	config.dev = &sw->dev;
296 	config.owner = THIS_MODULE;
297 	config.priv = sw;
298 
299 	return nvmem_register(&config);
300 }
301 
302 static int tb_switch_nvm_add(struct tb_switch *sw)
303 {
304 	struct nvmem_device *nvm_dev;
305 	struct tb_switch_nvm *nvm;
306 	u32 val;
307 	int ret;
308 
309 	if (!sw->dma_port)
310 		return 0;
311 
312 	nvm = kzalloc(sizeof(*nvm), GFP_KERNEL);
313 	if (!nvm)
314 		return -ENOMEM;
315 
316 	nvm->id = ida_simple_get(&nvm_ida, 0, 0, GFP_KERNEL);
317 
318 	/*
319 	 * If the switch is in safe-mode the only accessible portion of
320 	 * the NVM is the non-active one where userspace is expected to
321 	 * write new functional NVM.
322 	 */
323 	if (!sw->safe_mode) {
324 		u32 nvm_size, hdr_size;
325 
326 		ret = dma_port_flash_read(sw->dma_port, NVM_FLASH_SIZE, &val,
327 					  sizeof(val));
328 		if (ret)
329 			goto err_ida;
330 
331 		hdr_size = sw->generation < 3 ? SZ_8K : SZ_16K;
332 		nvm_size = (SZ_1M << (val & 7)) / 8;
333 		nvm_size = (nvm_size - hdr_size) / 2;
334 
335 		ret = dma_port_flash_read(sw->dma_port, NVM_VERSION, &val,
336 					  sizeof(val));
337 		if (ret)
338 			goto err_ida;
339 
340 		nvm->major = val >> 16;
341 		nvm->minor = val >> 8;
342 
343 		nvm_dev = register_nvmem(sw, nvm->id, nvm_size, true);
344 		if (IS_ERR(nvm_dev)) {
345 			ret = PTR_ERR(nvm_dev);
346 			goto err_ida;
347 		}
348 		nvm->active = nvm_dev;
349 	}
350 
351 	nvm_dev = register_nvmem(sw, nvm->id, NVM_MAX_SIZE, false);
352 	if (IS_ERR(nvm_dev)) {
353 		ret = PTR_ERR(nvm_dev);
354 		goto err_nvm_active;
355 	}
356 	nvm->non_active = nvm_dev;
357 
358 	mutex_lock(&switch_lock);
359 	sw->nvm = nvm;
360 	mutex_unlock(&switch_lock);
361 
362 	return 0;
363 
364 err_nvm_active:
365 	if (nvm->active)
366 		nvmem_unregister(nvm->active);
367 err_ida:
368 	ida_simple_remove(&nvm_ida, nvm->id);
369 	kfree(nvm);
370 
371 	return ret;
372 }
373 
374 static void tb_switch_nvm_remove(struct tb_switch *sw)
375 {
376 	struct tb_switch_nvm *nvm;
377 
378 	mutex_lock(&switch_lock);
379 	nvm = sw->nvm;
380 	sw->nvm = NULL;
381 	mutex_unlock(&switch_lock);
382 
383 	if (!nvm)
384 		return;
385 
386 	/* Remove authentication status in case the switch is unplugged */
387 	if (!nvm->authenticating)
388 		nvm_clear_auth_status(sw);
389 
390 	nvmem_unregister(nvm->non_active);
391 	if (nvm->active)
392 		nvmem_unregister(nvm->active);
393 	ida_simple_remove(&nvm_ida, nvm->id);
394 	vfree(nvm->buf);
395 	kfree(nvm);
396 }
397 
398 /* port utility functions */
399 
400 static const char *tb_port_type(struct tb_regs_port_header *port)
401 {
402 	switch (port->type >> 16) {
403 	case 0:
404 		switch ((u8) port->type) {
405 		case 0:
406 			return "Inactive";
407 		case 1:
408 			return "Port";
409 		case 2:
410 			return "NHI";
411 		default:
412 			return "unknown";
413 		}
414 	case 0x2:
415 		return "Ethernet";
416 	case 0x8:
417 		return "SATA";
418 	case 0xe:
419 		return "DP/HDMI";
420 	case 0x10:
421 		return "PCIe";
422 	case 0x20:
423 		return "USB";
424 	default:
425 		return "unknown";
426 	}
427 }
428 
429 static void tb_dump_port(struct tb *tb, struct tb_regs_port_header *port)
430 {
431 	tb_info(tb,
432 		" Port %d: %x:%x (Revision: %d, TB Version: %d, Type: %s (%#x))\n",
433 		port->port_number, port->vendor_id, port->device_id,
434 		port->revision, port->thunderbolt_version, tb_port_type(port),
435 		port->type);
436 	tb_info(tb, "  Max hop id (in/out): %d/%d\n",
437 		port->max_in_hop_id, port->max_out_hop_id);
438 	tb_info(tb, "  Max counters: %d\n", port->max_counters);
439 	tb_info(tb, "  NFC Credits: %#x\n", port->nfc_credits);
440 }
441 
442 /**
443  * tb_port_state() - get connectedness state of a port
444  *
445  * The port must have a TB_CAP_PHY (i.e. it should be a real port).
446  *
447  * Return: Returns an enum tb_port_state on success or an error code on failure.
448  */
449 static int tb_port_state(struct tb_port *port)
450 {
451 	struct tb_cap_phy phy;
452 	int res;
453 	if (port->cap_phy == 0) {
454 		tb_port_WARN(port, "does not have a PHY\n");
455 		return -EINVAL;
456 	}
457 	res = tb_port_read(port, &phy, TB_CFG_PORT, port->cap_phy, 2);
458 	if (res)
459 		return res;
460 	return phy.state;
461 }
462 
463 /**
464  * tb_wait_for_port() - wait for a port to become ready
465  *
466  * Wait up to 1 second for a port to reach state TB_PORT_UP. If
467  * wait_if_unplugged is set then we also wait if the port is in state
468  * TB_PORT_UNPLUGGED (it takes a while for the device to be registered after
469  * switch resume). Otherwise we only wait if a device is registered but the link
470  * has not yet been established.
471  *
472  * Return: Returns an error code on failure. Returns 0 if the port is not
473  * connected or failed to reach state TB_PORT_UP within one second. Returns 1
474  * if the port is connected and in state TB_PORT_UP.
475  */
476 int tb_wait_for_port(struct tb_port *port, bool wait_if_unplugged)
477 {
478 	int retries = 10;
479 	int state;
480 	if (!port->cap_phy) {
481 		tb_port_WARN(port, "does not have PHY\n");
482 		return -EINVAL;
483 	}
484 	if (tb_is_upstream_port(port)) {
485 		tb_port_WARN(port, "is the upstream port\n");
486 		return -EINVAL;
487 	}
488 
489 	while (retries--) {
490 		state = tb_port_state(port);
491 		if (state < 0)
492 			return state;
493 		if (state == TB_PORT_DISABLED) {
494 			tb_port_info(port, "is disabled (state: 0)\n");
495 			return 0;
496 		}
497 		if (state == TB_PORT_UNPLUGGED) {
498 			if (wait_if_unplugged) {
499 				/* used during resume */
500 				tb_port_info(port,
501 					     "is unplugged (state: 7), retrying...\n");
502 				msleep(100);
503 				continue;
504 			}
505 			tb_port_info(port, "is unplugged (state: 7)\n");
506 			return 0;
507 		}
508 		if (state == TB_PORT_UP) {
509 			tb_port_info(port,
510 				     "is connected, link is up (state: 2)\n");
511 			return 1;
512 		}
513 
514 		/*
515 		 * After plug-in the state is TB_PORT_CONNECTING. Give it some
516 		 * time.
517 		 */
518 		tb_port_info(port,
519 			     "is connected, link is not up (state: %d), retrying...\n",
520 			     state);
521 		msleep(100);
522 	}
523 	tb_port_warn(port,
524 		     "failed to reach state TB_PORT_UP. Ignoring port...\n");
525 	return 0;
526 }
527 
528 /**
529  * tb_port_add_nfc_credits() - add/remove non flow controlled credits to port
530  *
531  * Change the number of NFC credits allocated to @port by @credits. To remove
532  * NFC credits pass a negative amount of credits.
533  *
534  * Return: Returns 0 on success or an error code on failure.
535  */
536 int tb_port_add_nfc_credits(struct tb_port *port, int credits)
537 {
538 	if (credits == 0)
539 		return 0;
540 	tb_port_info(port,
541 		     "adding %#x NFC credits (%#x -> %#x)",
542 		     credits,
543 		     port->config.nfc_credits,
544 		     port->config.nfc_credits + credits);
545 	port->config.nfc_credits += credits;
546 	return tb_port_write(port, &port->config.nfc_credits,
547 			     TB_CFG_PORT, 4, 1);
548 }
549 
550 /**
551  * tb_port_clear_counter() - clear a counter in TB_CFG_COUNTER
552  *
553  * Return: Returns 0 on success or an error code on failure.
554  */
555 int tb_port_clear_counter(struct tb_port *port, int counter)
556 {
557 	u32 zero[3] = { 0, 0, 0 };
558 	tb_port_info(port, "clearing counter %d\n", counter);
559 	return tb_port_write(port, zero, TB_CFG_COUNTERS, 3 * counter, 3);
560 }
561 
562 /**
563  * tb_init_port() - initialize a port
564  *
565  * This is a helper method for tb_switch_alloc. Does not check or initialize
566  * any downstream switches.
567  *
568  * Return: Returns 0 on success or an error code on failure.
569  */
570 static int tb_init_port(struct tb_port *port)
571 {
572 	int res;
573 	int cap;
574 
575 	res = tb_port_read(port, &port->config, TB_CFG_PORT, 0, 8);
576 	if (res)
577 		return res;
578 
579 	/* Port 0 is the switch itself and has no PHY. */
580 	if (port->config.type == TB_TYPE_PORT && port->port != 0) {
581 		cap = tb_port_find_cap(port, TB_PORT_CAP_PHY);
582 
583 		if (cap > 0)
584 			port->cap_phy = cap;
585 		else
586 			tb_port_WARN(port, "non switch port without a PHY\n");
587 	}
588 
589 	tb_dump_port(port->sw->tb, &port->config);
590 
591 	/* TODO: Read dual link port, DP port and more from EEPROM. */
592 	return 0;
593 
594 }
595 
596 /* switch utility functions */
597 
598 static void tb_dump_switch(struct tb *tb, struct tb_regs_switch_header *sw)
599 {
600 	tb_info(tb,
601 		" Switch: %x:%x (Revision: %d, TB Version: %d)\n",
602 		sw->vendor_id, sw->device_id, sw->revision,
603 		sw->thunderbolt_version);
604 	tb_info(tb, "  Max Port Number: %d\n", sw->max_port_number);
605 	tb_info(tb, "  Config:\n");
606 	tb_info(tb,
607 		"   Upstream Port Number: %d Depth: %d Route String: %#llx Enabled: %d, PlugEventsDelay: %dms\n",
608 		sw->upstream_port_number, sw->depth,
609 		(((u64) sw->route_hi) << 32) | sw->route_lo,
610 		sw->enabled, sw->plug_events_delay);
611 	tb_info(tb,
612 		"   unknown1: %#x unknown4: %#x\n",
613 		sw->__unknown1, sw->__unknown4);
614 }
615 
616 /**
617  * reset_switch() - reconfigure route, enable and send TB_CFG_PKG_RESET
618  *
619  * Return: Returns 0 on success or an error code on failure.
620  */
621 int tb_switch_reset(struct tb *tb, u64 route)
622 {
623 	struct tb_cfg_result res;
624 	struct tb_regs_switch_header header = {
625 		header.route_hi = route >> 32,
626 		header.route_lo = route,
627 		header.enabled = true,
628 	};
629 	tb_info(tb, "resetting switch at %llx\n", route);
630 	res.err = tb_cfg_write(tb->ctl, ((u32 *) &header) + 2, route,
631 			0, 2, 2, 2);
632 	if (res.err)
633 		return res.err;
634 	res = tb_cfg_reset(tb->ctl, route, TB_CFG_DEFAULT_TIMEOUT);
635 	if (res.err > 0)
636 		return -EIO;
637 	return res.err;
638 }
639 
640 struct tb_switch *get_switch_at_route(struct tb_switch *sw, u64 route)
641 {
642 	u8 next_port = route; /*
643 			       * Routes use a stride of 8 bits,
644 			       * eventhough a port index has 6 bits at most.
645 			       * */
646 	if (route == 0)
647 		return sw;
648 	if (next_port > sw->config.max_port_number)
649 		return NULL;
650 	if (tb_is_upstream_port(&sw->ports[next_port]))
651 		return NULL;
652 	if (!sw->ports[next_port].remote)
653 		return NULL;
654 	return get_switch_at_route(sw->ports[next_port].remote->sw,
655 				   route >> TB_ROUTE_SHIFT);
656 }
657 
658 /**
659  * tb_plug_events_active() - enable/disable plug events on a switch
660  *
661  * Also configures a sane plug_events_delay of 255ms.
662  *
663  * Return: Returns 0 on success or an error code on failure.
664  */
665 static int tb_plug_events_active(struct tb_switch *sw, bool active)
666 {
667 	u32 data;
668 	int res;
669 
670 	if (!sw->config.enabled)
671 		return 0;
672 
673 	sw->config.plug_events_delay = 0xff;
674 	res = tb_sw_write(sw, ((u32 *) &sw->config) + 4, TB_CFG_SWITCH, 4, 1);
675 	if (res)
676 		return res;
677 
678 	res = tb_sw_read(sw, &data, TB_CFG_SWITCH, sw->cap_plug_events + 1, 1);
679 	if (res)
680 		return res;
681 
682 	if (active) {
683 		data = data & 0xFFFFFF83;
684 		switch (sw->config.device_id) {
685 		case PCI_DEVICE_ID_INTEL_LIGHT_RIDGE:
686 		case PCI_DEVICE_ID_INTEL_EAGLE_RIDGE:
687 		case PCI_DEVICE_ID_INTEL_PORT_RIDGE:
688 			break;
689 		default:
690 			data |= 4;
691 		}
692 	} else {
693 		data = data | 0x7c;
694 	}
695 	return tb_sw_write(sw, &data, TB_CFG_SWITCH,
696 			   sw->cap_plug_events + 1, 1);
697 }
698 
699 static ssize_t authorized_show(struct device *dev,
700 			       struct device_attribute *attr,
701 			       char *buf)
702 {
703 	struct tb_switch *sw = tb_to_switch(dev);
704 
705 	return sprintf(buf, "%u\n", sw->authorized);
706 }
707 
708 static int tb_switch_set_authorized(struct tb_switch *sw, unsigned int val)
709 {
710 	int ret = -EINVAL;
711 
712 	if (mutex_lock_interruptible(&switch_lock))
713 		return -ERESTARTSYS;
714 
715 	if (sw->authorized)
716 		goto unlock;
717 
718 	switch (val) {
719 	/* Approve switch */
720 	case 1:
721 		if (sw->key)
722 			ret = tb_domain_approve_switch_key(sw->tb, sw);
723 		else
724 			ret = tb_domain_approve_switch(sw->tb, sw);
725 		break;
726 
727 	/* Challenge switch */
728 	case 2:
729 		if (sw->key)
730 			ret = tb_domain_challenge_switch_key(sw->tb, sw);
731 		break;
732 
733 	default:
734 		break;
735 	}
736 
737 	if (!ret) {
738 		sw->authorized = val;
739 		/* Notify status change to the userspace */
740 		kobject_uevent(&sw->dev.kobj, KOBJ_CHANGE);
741 	}
742 
743 unlock:
744 	mutex_unlock(&switch_lock);
745 	return ret;
746 }
747 
748 static ssize_t authorized_store(struct device *dev,
749 				struct device_attribute *attr,
750 				const char *buf, size_t count)
751 {
752 	struct tb_switch *sw = tb_to_switch(dev);
753 	unsigned int val;
754 	ssize_t ret;
755 
756 	ret = kstrtouint(buf, 0, &val);
757 	if (ret)
758 		return ret;
759 	if (val > 2)
760 		return -EINVAL;
761 
762 	ret = tb_switch_set_authorized(sw, val);
763 
764 	return ret ? ret : count;
765 }
766 static DEVICE_ATTR_RW(authorized);
767 
768 static ssize_t device_show(struct device *dev, struct device_attribute *attr,
769 			   char *buf)
770 {
771 	struct tb_switch *sw = tb_to_switch(dev);
772 
773 	return sprintf(buf, "%#x\n", sw->device);
774 }
775 static DEVICE_ATTR_RO(device);
776 
777 static ssize_t
778 device_name_show(struct device *dev, struct device_attribute *attr, char *buf)
779 {
780 	struct tb_switch *sw = tb_to_switch(dev);
781 
782 	return sprintf(buf, "%s\n", sw->device_name ? sw->device_name : "");
783 }
784 static DEVICE_ATTR_RO(device_name);
785 
786 static ssize_t key_show(struct device *dev, struct device_attribute *attr,
787 			char *buf)
788 {
789 	struct tb_switch *sw = tb_to_switch(dev);
790 	ssize_t ret;
791 
792 	if (mutex_lock_interruptible(&switch_lock))
793 		return -ERESTARTSYS;
794 
795 	if (sw->key)
796 		ret = sprintf(buf, "%*phN\n", TB_SWITCH_KEY_SIZE, sw->key);
797 	else
798 		ret = sprintf(buf, "\n");
799 
800 	mutex_unlock(&switch_lock);
801 	return ret;
802 }
803 
804 static ssize_t key_store(struct device *dev, struct device_attribute *attr,
805 			 const char *buf, size_t count)
806 {
807 	struct tb_switch *sw = tb_to_switch(dev);
808 	u8 key[TB_SWITCH_KEY_SIZE];
809 	ssize_t ret = count;
810 
811 	if (count < 64)
812 		return -EINVAL;
813 
814 	if (hex2bin(key, buf, sizeof(key)))
815 		return -EINVAL;
816 
817 	if (mutex_lock_interruptible(&switch_lock))
818 		return -ERESTARTSYS;
819 
820 	if (sw->authorized) {
821 		ret = -EBUSY;
822 	} else {
823 		kfree(sw->key);
824 		sw->key = kmemdup(key, sizeof(key), GFP_KERNEL);
825 		if (!sw->key)
826 			ret = -ENOMEM;
827 	}
828 
829 	mutex_unlock(&switch_lock);
830 	return ret;
831 }
832 static DEVICE_ATTR_RW(key);
833 
834 static ssize_t nvm_authenticate_show(struct device *dev,
835 	struct device_attribute *attr, char *buf)
836 {
837 	struct tb_switch *sw = tb_to_switch(dev);
838 	u32 status;
839 
840 	nvm_get_auth_status(sw, &status);
841 	return sprintf(buf, "%#x\n", status);
842 }
843 
844 static ssize_t nvm_authenticate_store(struct device *dev,
845 	struct device_attribute *attr, const char *buf, size_t count)
846 {
847 	struct tb_switch *sw = tb_to_switch(dev);
848 	bool val;
849 	int ret;
850 
851 	if (mutex_lock_interruptible(&switch_lock))
852 		return -ERESTARTSYS;
853 
854 	/* If NVMem devices are not yet added */
855 	if (!sw->nvm) {
856 		ret = -EAGAIN;
857 		goto exit_unlock;
858 	}
859 
860 	ret = kstrtobool(buf, &val);
861 	if (ret)
862 		goto exit_unlock;
863 
864 	/* Always clear the authentication status */
865 	nvm_clear_auth_status(sw);
866 
867 	if (val) {
868 		ret = nvm_validate_and_write(sw);
869 		if (ret)
870 			goto exit_unlock;
871 
872 		sw->nvm->authenticating = true;
873 
874 		if (!tb_route(sw))
875 			ret = nvm_authenticate_host(sw);
876 		else
877 			ret = nvm_authenticate_device(sw);
878 	}
879 
880 exit_unlock:
881 	mutex_unlock(&switch_lock);
882 
883 	if (ret)
884 		return ret;
885 	return count;
886 }
887 static DEVICE_ATTR_RW(nvm_authenticate);
888 
889 static ssize_t nvm_version_show(struct device *dev,
890 				struct device_attribute *attr, char *buf)
891 {
892 	struct tb_switch *sw = tb_to_switch(dev);
893 	int ret;
894 
895 	if (mutex_lock_interruptible(&switch_lock))
896 		return -ERESTARTSYS;
897 
898 	if (sw->safe_mode)
899 		ret = -ENODATA;
900 	else if (!sw->nvm)
901 		ret = -EAGAIN;
902 	else
903 		ret = sprintf(buf, "%x.%x\n", sw->nvm->major, sw->nvm->minor);
904 
905 	mutex_unlock(&switch_lock);
906 
907 	return ret;
908 }
909 static DEVICE_ATTR_RO(nvm_version);
910 
911 static ssize_t vendor_show(struct device *dev, struct device_attribute *attr,
912 			   char *buf)
913 {
914 	struct tb_switch *sw = tb_to_switch(dev);
915 
916 	return sprintf(buf, "%#x\n", sw->vendor);
917 }
918 static DEVICE_ATTR_RO(vendor);
919 
920 static ssize_t
921 vendor_name_show(struct device *dev, struct device_attribute *attr, char *buf)
922 {
923 	struct tb_switch *sw = tb_to_switch(dev);
924 
925 	return sprintf(buf, "%s\n", sw->vendor_name ? sw->vendor_name : "");
926 }
927 static DEVICE_ATTR_RO(vendor_name);
928 
929 static ssize_t unique_id_show(struct device *dev, struct device_attribute *attr,
930 			      char *buf)
931 {
932 	struct tb_switch *sw = tb_to_switch(dev);
933 
934 	return sprintf(buf, "%pUb\n", sw->uuid);
935 }
936 static DEVICE_ATTR_RO(unique_id);
937 
938 static struct attribute *switch_attrs[] = {
939 	&dev_attr_authorized.attr,
940 	&dev_attr_device.attr,
941 	&dev_attr_device_name.attr,
942 	&dev_attr_key.attr,
943 	&dev_attr_nvm_authenticate.attr,
944 	&dev_attr_nvm_version.attr,
945 	&dev_attr_vendor.attr,
946 	&dev_attr_vendor_name.attr,
947 	&dev_attr_unique_id.attr,
948 	NULL,
949 };
950 
951 static umode_t switch_attr_is_visible(struct kobject *kobj,
952 				      struct attribute *attr, int n)
953 {
954 	struct device *dev = container_of(kobj, struct device, kobj);
955 	struct tb_switch *sw = tb_to_switch(dev);
956 
957 	if (attr == &dev_attr_key.attr) {
958 		if (tb_route(sw) &&
959 		    sw->tb->security_level == TB_SECURITY_SECURE &&
960 		    sw->security_level == TB_SECURITY_SECURE)
961 			return attr->mode;
962 		return 0;
963 	} else if (attr == &dev_attr_nvm_authenticate.attr ||
964 		   attr == &dev_attr_nvm_version.attr) {
965 		if (sw->dma_port)
966 			return attr->mode;
967 		return 0;
968 	}
969 
970 	return sw->safe_mode ? 0 : attr->mode;
971 }
972 
973 static struct attribute_group switch_group = {
974 	.is_visible = switch_attr_is_visible,
975 	.attrs = switch_attrs,
976 };
977 
978 static const struct attribute_group *switch_groups[] = {
979 	&switch_group,
980 	NULL,
981 };
982 
983 static void tb_switch_release(struct device *dev)
984 {
985 	struct tb_switch *sw = tb_to_switch(dev);
986 
987 	dma_port_free(sw->dma_port);
988 
989 	kfree(sw->uuid);
990 	kfree(sw->device_name);
991 	kfree(sw->vendor_name);
992 	kfree(sw->ports);
993 	kfree(sw->drom);
994 	kfree(sw->key);
995 	kfree(sw);
996 }
997 
998 struct device_type tb_switch_type = {
999 	.name = "thunderbolt_device",
1000 	.release = tb_switch_release,
1001 };
1002 
1003 static int tb_switch_get_generation(struct tb_switch *sw)
1004 {
1005 	switch (sw->config.device_id) {
1006 	case PCI_DEVICE_ID_INTEL_LIGHT_RIDGE:
1007 	case PCI_DEVICE_ID_INTEL_EAGLE_RIDGE:
1008 	case PCI_DEVICE_ID_INTEL_LIGHT_PEAK:
1009 	case PCI_DEVICE_ID_INTEL_CACTUS_RIDGE_2C:
1010 	case PCI_DEVICE_ID_INTEL_CACTUS_RIDGE_4C:
1011 	case PCI_DEVICE_ID_INTEL_PORT_RIDGE:
1012 	case PCI_DEVICE_ID_INTEL_REDWOOD_RIDGE_2C_BRIDGE:
1013 	case PCI_DEVICE_ID_INTEL_REDWOOD_RIDGE_4C_BRIDGE:
1014 		return 1;
1015 
1016 	case PCI_DEVICE_ID_INTEL_WIN_RIDGE_2C_BRIDGE:
1017 	case PCI_DEVICE_ID_INTEL_FALCON_RIDGE_2C_BRIDGE:
1018 	case PCI_DEVICE_ID_INTEL_FALCON_RIDGE_4C_BRIDGE:
1019 		return 2;
1020 
1021 	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_LP_BRIDGE:
1022 	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_2C_BRIDGE:
1023 	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_4C_BRIDGE:
1024 	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_2C_BRIDGE:
1025 	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_4C_BRIDGE:
1026 		return 3;
1027 
1028 	default:
1029 		/*
1030 		 * For unknown switches assume generation to be 1 to be
1031 		 * on the safe side.
1032 		 */
1033 		tb_sw_warn(sw, "unsupported switch device id %#x\n",
1034 			   sw->config.device_id);
1035 		return 1;
1036 	}
1037 }
1038 
1039 /**
1040  * tb_switch_alloc() - allocate a switch
1041  * @tb: Pointer to the owning domain
1042  * @parent: Parent device for this switch
1043  * @route: Route string for this switch
1044  *
1045  * Allocates and initializes a switch. Will not upload configuration to
1046  * the switch. For that you need to call tb_switch_configure()
1047  * separately. The returned switch should be released by calling
1048  * tb_switch_put().
1049  *
1050  * Return: Pointer to the allocated switch or %NULL in case of failure
1051  */
1052 struct tb_switch *tb_switch_alloc(struct tb *tb, struct device *parent,
1053 				  u64 route)
1054 {
1055 	int i;
1056 	int cap;
1057 	struct tb_switch *sw;
1058 	int upstream_port = tb_cfg_get_upstream_port(tb->ctl, route);
1059 	if (upstream_port < 0)
1060 		return NULL;
1061 
1062 	sw = kzalloc(sizeof(*sw), GFP_KERNEL);
1063 	if (!sw)
1064 		return NULL;
1065 
1066 	sw->tb = tb;
1067 	if (tb_cfg_read(tb->ctl, &sw->config, route, 0, TB_CFG_SWITCH, 0, 5))
1068 		goto err_free_sw_ports;
1069 
1070 	tb_info(tb, "current switch config:\n");
1071 	tb_dump_switch(tb, &sw->config);
1072 
1073 	/* configure switch */
1074 	sw->config.upstream_port_number = upstream_port;
1075 	sw->config.depth = tb_route_length(route);
1076 	sw->config.route_lo = route;
1077 	sw->config.route_hi = route >> 32;
1078 	sw->config.enabled = 0;
1079 
1080 	/* initialize ports */
1081 	sw->ports = kcalloc(sw->config.max_port_number + 1, sizeof(*sw->ports),
1082 				GFP_KERNEL);
1083 	if (!sw->ports)
1084 		goto err_free_sw_ports;
1085 
1086 	for (i = 0; i <= sw->config.max_port_number; i++) {
1087 		/* minimum setup for tb_find_cap and tb_drom_read to work */
1088 		sw->ports[i].sw = sw;
1089 		sw->ports[i].port = i;
1090 	}
1091 
1092 	sw->generation = tb_switch_get_generation(sw);
1093 
1094 	cap = tb_switch_find_vse_cap(sw, TB_VSE_CAP_PLUG_EVENTS);
1095 	if (cap < 0) {
1096 		tb_sw_warn(sw, "cannot find TB_VSE_CAP_PLUG_EVENTS aborting\n");
1097 		goto err_free_sw_ports;
1098 	}
1099 	sw->cap_plug_events = cap;
1100 
1101 	/* Root switch is always authorized */
1102 	if (!route)
1103 		sw->authorized = true;
1104 
1105 	device_initialize(&sw->dev);
1106 	sw->dev.parent = parent;
1107 	sw->dev.bus = &tb_bus_type;
1108 	sw->dev.type = &tb_switch_type;
1109 	sw->dev.groups = switch_groups;
1110 	dev_set_name(&sw->dev, "%u-%llx", tb->index, tb_route(sw));
1111 
1112 	return sw;
1113 
1114 err_free_sw_ports:
1115 	kfree(sw->ports);
1116 	kfree(sw);
1117 
1118 	return NULL;
1119 }
1120 
1121 /**
1122  * tb_switch_alloc_safe_mode() - allocate a switch that is in safe mode
1123  * @tb: Pointer to the owning domain
1124  * @parent: Parent device for this switch
1125  * @route: Route string for this switch
1126  *
1127  * This creates a switch in safe mode. This means the switch pretty much
1128  * lacks all capabilities except DMA configuration port before it is
1129  * flashed with a valid NVM firmware.
1130  *
1131  * The returned switch must be released by calling tb_switch_put().
1132  *
1133  * Return: Pointer to the allocated switch or %NULL in case of failure
1134  */
1135 struct tb_switch *
1136 tb_switch_alloc_safe_mode(struct tb *tb, struct device *parent, u64 route)
1137 {
1138 	struct tb_switch *sw;
1139 
1140 	sw = kzalloc(sizeof(*sw), GFP_KERNEL);
1141 	if (!sw)
1142 		return NULL;
1143 
1144 	sw->tb = tb;
1145 	sw->config.depth = tb_route_length(route);
1146 	sw->config.route_hi = upper_32_bits(route);
1147 	sw->config.route_lo = lower_32_bits(route);
1148 	sw->safe_mode = true;
1149 
1150 	device_initialize(&sw->dev);
1151 	sw->dev.parent = parent;
1152 	sw->dev.bus = &tb_bus_type;
1153 	sw->dev.type = &tb_switch_type;
1154 	sw->dev.groups = switch_groups;
1155 	dev_set_name(&sw->dev, "%u-%llx", tb->index, tb_route(sw));
1156 
1157 	return sw;
1158 }
1159 
1160 /**
1161  * tb_switch_configure() - Uploads configuration to the switch
1162  * @sw: Switch to configure
1163  *
1164  * Call this function before the switch is added to the system. It will
1165  * upload configuration to the switch and makes it available for the
1166  * connection manager to use.
1167  *
1168  * Return: %0 in case of success and negative errno in case of failure
1169  */
1170 int tb_switch_configure(struct tb_switch *sw)
1171 {
1172 	struct tb *tb = sw->tb;
1173 	u64 route;
1174 	int ret;
1175 
1176 	route = tb_route(sw);
1177 	tb_info(tb,
1178 		"initializing Switch at %#llx (depth: %d, up port: %d)\n",
1179 		route, tb_route_length(route), sw->config.upstream_port_number);
1180 
1181 	if (sw->config.vendor_id != PCI_VENDOR_ID_INTEL)
1182 		tb_sw_warn(sw, "unknown switch vendor id %#x\n",
1183 			   sw->config.vendor_id);
1184 
1185 	sw->config.enabled = 1;
1186 
1187 	/* upload configuration */
1188 	ret = tb_sw_write(sw, 1 + (u32 *)&sw->config, TB_CFG_SWITCH, 1, 3);
1189 	if (ret)
1190 		return ret;
1191 
1192 	return tb_plug_events_active(sw, true);
1193 }
1194 
1195 static void tb_switch_set_uuid(struct tb_switch *sw)
1196 {
1197 	u32 uuid[4];
1198 	int cap;
1199 
1200 	if (sw->uuid)
1201 		return;
1202 
1203 	/*
1204 	 * The newer controllers include fused UUID as part of link
1205 	 * controller specific registers
1206 	 */
1207 	cap = tb_switch_find_vse_cap(sw, TB_VSE_CAP_LINK_CONTROLLER);
1208 	if (cap > 0) {
1209 		tb_sw_read(sw, uuid, TB_CFG_SWITCH, cap + 3, 4);
1210 	} else {
1211 		/*
1212 		 * ICM generates UUID based on UID and fills the upper
1213 		 * two words with ones. This is not strictly following
1214 		 * UUID format but we want to be compatible with it so
1215 		 * we do the same here.
1216 		 */
1217 		uuid[0] = sw->uid & 0xffffffff;
1218 		uuid[1] = (sw->uid >> 32) & 0xffffffff;
1219 		uuid[2] = 0xffffffff;
1220 		uuid[3] = 0xffffffff;
1221 	}
1222 
1223 	sw->uuid = kmemdup(uuid, sizeof(uuid), GFP_KERNEL);
1224 }
1225 
1226 static int tb_switch_add_dma_port(struct tb_switch *sw)
1227 {
1228 	u32 status;
1229 	int ret;
1230 
1231 	switch (sw->generation) {
1232 	case 3:
1233 		break;
1234 
1235 	case 2:
1236 		/* Only root switch can be upgraded */
1237 		if (tb_route(sw))
1238 			return 0;
1239 		break;
1240 
1241 	default:
1242 		/*
1243 		 * DMA port is the only thing available when the switch
1244 		 * is in safe mode.
1245 		 */
1246 		if (!sw->safe_mode)
1247 			return 0;
1248 		break;
1249 	}
1250 
1251 	if (sw->no_nvm_upgrade)
1252 		return 0;
1253 
1254 	sw->dma_port = dma_port_alloc(sw);
1255 	if (!sw->dma_port)
1256 		return 0;
1257 
1258 	/*
1259 	 * Check status of the previous flash authentication. If there
1260 	 * is one we need to power cycle the switch in any case to make
1261 	 * it functional again.
1262 	 */
1263 	ret = dma_port_flash_update_auth_status(sw->dma_port, &status);
1264 	if (ret <= 0)
1265 		return ret;
1266 
1267 	if (status) {
1268 		tb_sw_info(sw, "switch flash authentication failed\n");
1269 		tb_switch_set_uuid(sw);
1270 		nvm_set_auth_status(sw, status);
1271 	}
1272 
1273 	tb_sw_info(sw, "power cycling the switch now\n");
1274 	dma_port_power_cycle(sw->dma_port);
1275 
1276 	/*
1277 	 * We return error here which causes the switch adding failure.
1278 	 * It should appear back after power cycle is complete.
1279 	 */
1280 	return -ESHUTDOWN;
1281 }
1282 
1283 /**
1284  * tb_switch_add() - Add a switch to the domain
1285  * @sw: Switch to add
1286  *
1287  * This is the last step in adding switch to the domain. It will read
1288  * identification information from DROM and initializes ports so that
1289  * they can be used to connect other switches. The switch will be
1290  * exposed to the userspace when this function successfully returns. To
1291  * remove and release the switch, call tb_switch_remove().
1292  *
1293  * Return: %0 in case of success and negative errno in case of failure
1294  */
1295 int tb_switch_add(struct tb_switch *sw)
1296 {
1297 	int i, ret;
1298 
1299 	/*
1300 	 * Initialize DMA control port now before we read DROM. Recent
1301 	 * host controllers have more complete DROM on NVM that includes
1302 	 * vendor and model identification strings which we then expose
1303 	 * to the userspace. NVM can be accessed through DMA
1304 	 * configuration based mailbox.
1305 	 */
1306 	ret = tb_switch_add_dma_port(sw);
1307 	if (ret)
1308 		return ret;
1309 
1310 	if (!sw->safe_mode) {
1311 		/* read drom */
1312 		ret = tb_drom_read(sw);
1313 		if (ret) {
1314 			tb_sw_warn(sw, "tb_eeprom_read_rom failed\n");
1315 			return ret;
1316 		}
1317 		tb_sw_info(sw, "uid: %#llx\n", sw->uid);
1318 
1319 		tb_switch_set_uuid(sw);
1320 
1321 		for (i = 0; i <= sw->config.max_port_number; i++) {
1322 			if (sw->ports[i].disabled) {
1323 				tb_port_info(&sw->ports[i], "disabled by eeprom\n");
1324 				continue;
1325 			}
1326 			ret = tb_init_port(&sw->ports[i]);
1327 			if (ret)
1328 				return ret;
1329 		}
1330 	}
1331 
1332 	ret = device_add(&sw->dev);
1333 	if (ret)
1334 		return ret;
1335 
1336 	ret = tb_switch_nvm_add(sw);
1337 	if (ret)
1338 		device_del(&sw->dev);
1339 
1340 	return ret;
1341 }
1342 
1343 /**
1344  * tb_switch_remove() - Remove and release a switch
1345  * @sw: Switch to remove
1346  *
1347  * This will remove the switch from the domain and release it after last
1348  * reference count drops to zero. If there are switches connected below
1349  * this switch, they will be removed as well.
1350  */
1351 void tb_switch_remove(struct tb_switch *sw)
1352 {
1353 	int i;
1354 
1355 	/* port 0 is the switch itself and never has a remote */
1356 	for (i = 1; i <= sw->config.max_port_number; i++) {
1357 		if (tb_is_upstream_port(&sw->ports[i]))
1358 			continue;
1359 		if (sw->ports[i].remote)
1360 			tb_switch_remove(sw->ports[i].remote->sw);
1361 		sw->ports[i].remote = NULL;
1362 	}
1363 
1364 	if (!sw->is_unplugged)
1365 		tb_plug_events_active(sw, false);
1366 
1367 	tb_switch_nvm_remove(sw);
1368 	device_unregister(&sw->dev);
1369 }
1370 
1371 /**
1372  * tb_sw_set_unplugged() - set is_unplugged on switch and downstream switches
1373  */
1374 void tb_sw_set_unplugged(struct tb_switch *sw)
1375 {
1376 	int i;
1377 	if (sw == sw->tb->root_switch) {
1378 		tb_sw_WARN(sw, "cannot unplug root switch\n");
1379 		return;
1380 	}
1381 	if (sw->is_unplugged) {
1382 		tb_sw_WARN(sw, "is_unplugged already set\n");
1383 		return;
1384 	}
1385 	sw->is_unplugged = true;
1386 	for (i = 0; i <= sw->config.max_port_number; i++) {
1387 		if (!tb_is_upstream_port(&sw->ports[i]) && sw->ports[i].remote)
1388 			tb_sw_set_unplugged(sw->ports[i].remote->sw);
1389 	}
1390 }
1391 
1392 int tb_switch_resume(struct tb_switch *sw)
1393 {
1394 	int i, err;
1395 	tb_sw_info(sw, "resuming switch\n");
1396 
1397 	/*
1398 	 * Check for UID of the connected switches except for root
1399 	 * switch which we assume cannot be removed.
1400 	 */
1401 	if (tb_route(sw)) {
1402 		u64 uid;
1403 
1404 		err = tb_drom_read_uid_only(sw, &uid);
1405 		if (err) {
1406 			tb_sw_warn(sw, "uid read failed\n");
1407 			return err;
1408 		}
1409 		if (sw->uid != uid) {
1410 			tb_sw_info(sw,
1411 				"changed while suspended (uid %#llx -> %#llx)\n",
1412 				sw->uid, uid);
1413 			return -ENODEV;
1414 		}
1415 	}
1416 
1417 	/* upload configuration */
1418 	err = tb_sw_write(sw, 1 + (u32 *) &sw->config, TB_CFG_SWITCH, 1, 3);
1419 	if (err)
1420 		return err;
1421 
1422 	err = tb_plug_events_active(sw, true);
1423 	if (err)
1424 		return err;
1425 
1426 	/* check for surviving downstream switches */
1427 	for (i = 1; i <= sw->config.max_port_number; i++) {
1428 		struct tb_port *port = &sw->ports[i];
1429 		if (tb_is_upstream_port(port))
1430 			continue;
1431 		if (!port->remote)
1432 			continue;
1433 		if (tb_wait_for_port(port, true) <= 0
1434 			|| tb_switch_resume(port->remote->sw)) {
1435 			tb_port_warn(port,
1436 				     "lost during suspend, disconnecting\n");
1437 			tb_sw_set_unplugged(port->remote->sw);
1438 		}
1439 	}
1440 	return 0;
1441 }
1442 
1443 void tb_switch_suspend(struct tb_switch *sw)
1444 {
1445 	int i, err;
1446 	err = tb_plug_events_active(sw, false);
1447 	if (err)
1448 		return;
1449 
1450 	for (i = 1; i <= sw->config.max_port_number; i++) {
1451 		if (!tb_is_upstream_port(&sw->ports[i]) && sw->ports[i].remote)
1452 			tb_switch_suspend(sw->ports[i].remote->sw);
1453 	}
1454 	/*
1455 	 * TODO: invoke tb_cfg_prepare_to_sleep here? does not seem to have any
1456 	 * effect?
1457 	 */
1458 }
1459 
1460 struct tb_sw_lookup {
1461 	struct tb *tb;
1462 	u8 link;
1463 	u8 depth;
1464 	const uuid_t *uuid;
1465 };
1466 
1467 static int tb_switch_match(struct device *dev, void *data)
1468 {
1469 	struct tb_switch *sw = tb_to_switch(dev);
1470 	struct tb_sw_lookup *lookup = data;
1471 
1472 	if (!sw)
1473 		return 0;
1474 	if (sw->tb != lookup->tb)
1475 		return 0;
1476 
1477 	if (lookup->uuid)
1478 		return !memcmp(sw->uuid, lookup->uuid, sizeof(*lookup->uuid));
1479 
1480 	/* Root switch is matched only by depth */
1481 	if (!lookup->depth)
1482 		return !sw->depth;
1483 
1484 	return sw->link == lookup->link && sw->depth == lookup->depth;
1485 }
1486 
1487 /**
1488  * tb_switch_find_by_link_depth() - Find switch by link and depth
1489  * @tb: Domain the switch belongs
1490  * @link: Link number the switch is connected
1491  * @depth: Depth of the switch in link
1492  *
1493  * Returned switch has reference count increased so the caller needs to
1494  * call tb_switch_put() when done with the switch.
1495  */
1496 struct tb_switch *tb_switch_find_by_link_depth(struct tb *tb, u8 link, u8 depth)
1497 {
1498 	struct tb_sw_lookup lookup;
1499 	struct device *dev;
1500 
1501 	memset(&lookup, 0, sizeof(lookup));
1502 	lookup.tb = tb;
1503 	lookup.link = link;
1504 	lookup.depth = depth;
1505 
1506 	dev = bus_find_device(&tb_bus_type, NULL, &lookup, tb_switch_match);
1507 	if (dev)
1508 		return tb_to_switch(dev);
1509 
1510 	return NULL;
1511 }
1512 
1513 /**
1514  * tb_switch_find_by_link_depth() - Find switch by UUID
1515  * @tb: Domain the switch belongs
1516  * @uuid: UUID to look for
1517  *
1518  * Returned switch has reference count increased so the caller needs to
1519  * call tb_switch_put() when done with the switch.
1520  */
1521 struct tb_switch *tb_switch_find_by_uuid(struct tb *tb, const uuid_t *uuid)
1522 {
1523 	struct tb_sw_lookup lookup;
1524 	struct device *dev;
1525 
1526 	memset(&lookup, 0, sizeof(lookup));
1527 	lookup.tb = tb;
1528 	lookup.uuid = uuid;
1529 
1530 	dev = bus_find_device(&tb_bus_type, NULL, &lookup, tb_switch_match);
1531 	if (dev)
1532 		return tb_to_switch(dev);
1533 
1534 	return NULL;
1535 }
1536 
1537 void tb_switch_exit(void)
1538 {
1539 	ida_destroy(&nvm_ida);
1540 }
1541