xref: /openbmc/linux/drivers/thunderbolt/tunnel.c (revision c93db682)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Thunderbolt driver - Tunneling support
4  *
5  * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
6  * Copyright (C) 2019, Intel Corporation
7  */
8 
9 #include <linux/delay.h>
10 #include <linux/slab.h>
11 #include <linux/list.h>
12 
13 #include "tunnel.h"
14 #include "tb.h"
15 
16 /* PCIe adapters use always HopID of 8 for both directions */
17 #define TB_PCI_HOPID			8
18 
19 #define TB_PCI_PATH_DOWN		0
20 #define TB_PCI_PATH_UP			1
21 
22 /* USB3 adapters use always HopID of 8 for both directions */
23 #define TB_USB3_HOPID			8
24 
25 #define TB_USB3_PATH_DOWN		0
26 #define TB_USB3_PATH_UP			1
27 
28 /* DP adapters use HopID 8 for AUX and 9 for Video */
29 #define TB_DP_AUX_TX_HOPID		8
30 #define TB_DP_AUX_RX_HOPID		8
31 #define TB_DP_VIDEO_HOPID		9
32 
33 #define TB_DP_VIDEO_PATH_OUT		0
34 #define TB_DP_AUX_PATH_OUT		1
35 #define TB_DP_AUX_PATH_IN		2
36 
37 static const char * const tb_tunnel_names[] = { "PCI", "DP", "DMA", "USB3" };
38 
39 #define __TB_TUNNEL_PRINT(level, tunnel, fmt, arg...)                   \
40 	do {                                                            \
41 		struct tb_tunnel *__tunnel = (tunnel);                  \
42 		level(__tunnel->tb, "%llx:%x <-> %llx:%x (%s): " fmt,   \
43 		      tb_route(__tunnel->src_port->sw),                 \
44 		      __tunnel->src_port->port,                         \
45 		      tb_route(__tunnel->dst_port->sw),                 \
46 		      __tunnel->dst_port->port,                         \
47 		      tb_tunnel_names[__tunnel->type],			\
48 		      ## arg);                                          \
49 	} while (0)
50 
51 #define tb_tunnel_WARN(tunnel, fmt, arg...) \
52 	__TB_TUNNEL_PRINT(tb_WARN, tunnel, fmt, ##arg)
53 #define tb_tunnel_warn(tunnel, fmt, arg...) \
54 	__TB_TUNNEL_PRINT(tb_warn, tunnel, fmt, ##arg)
55 #define tb_tunnel_info(tunnel, fmt, arg...) \
56 	__TB_TUNNEL_PRINT(tb_info, tunnel, fmt, ##arg)
57 #define tb_tunnel_dbg(tunnel, fmt, arg...) \
58 	__TB_TUNNEL_PRINT(tb_dbg, tunnel, fmt, ##arg)
59 
60 static struct tb_tunnel *tb_tunnel_alloc(struct tb *tb, size_t npaths,
61 					 enum tb_tunnel_type type)
62 {
63 	struct tb_tunnel *tunnel;
64 
65 	tunnel = kzalloc(sizeof(*tunnel), GFP_KERNEL);
66 	if (!tunnel)
67 		return NULL;
68 
69 	tunnel->paths = kcalloc(npaths, sizeof(tunnel->paths[0]), GFP_KERNEL);
70 	if (!tunnel->paths) {
71 		tb_tunnel_free(tunnel);
72 		return NULL;
73 	}
74 
75 	INIT_LIST_HEAD(&tunnel->list);
76 	tunnel->tb = tb;
77 	tunnel->npaths = npaths;
78 	tunnel->type = type;
79 
80 	return tunnel;
81 }
82 
83 static int tb_pci_activate(struct tb_tunnel *tunnel, bool activate)
84 {
85 	int res;
86 
87 	res = tb_pci_port_enable(tunnel->src_port, activate);
88 	if (res)
89 		return res;
90 
91 	if (tb_port_is_pcie_up(tunnel->dst_port))
92 		return tb_pci_port_enable(tunnel->dst_port, activate);
93 
94 	return 0;
95 }
96 
97 static int tb_initial_credits(const struct tb_switch *sw)
98 {
99 	/* If the path is complete sw is not NULL */
100 	if (sw) {
101 		/* More credits for faster link */
102 		switch (sw->link_speed * sw->link_width) {
103 		case 40:
104 			return 32;
105 		case 20:
106 			return 24;
107 		}
108 	}
109 
110 	return 16;
111 }
112 
113 static void tb_pci_init_path(struct tb_path *path)
114 {
115 	path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
116 	path->egress_shared_buffer = TB_PATH_NONE;
117 	path->ingress_fc_enable = TB_PATH_ALL;
118 	path->ingress_shared_buffer = TB_PATH_NONE;
119 	path->priority = 3;
120 	path->weight = 1;
121 	path->drop_packages = 0;
122 	path->nfc_credits = 0;
123 	path->hops[0].initial_credits = 7;
124 	if (path->path_length > 1)
125 		path->hops[1].initial_credits =
126 			tb_initial_credits(path->hops[1].in_port->sw);
127 }
128 
129 /**
130  * tb_tunnel_discover_pci() - Discover existing PCIe tunnels
131  * @tb: Pointer to the domain structure
132  * @down: PCIe downstream adapter
133  *
134  * If @down adapter is active, follows the tunnel to the PCIe upstream
135  * adapter and back. Returns the discovered tunnel or %NULL if there was
136  * no tunnel.
137  */
138 struct tb_tunnel *tb_tunnel_discover_pci(struct tb *tb, struct tb_port *down)
139 {
140 	struct tb_tunnel *tunnel;
141 	struct tb_path *path;
142 
143 	if (!tb_pci_port_is_enabled(down))
144 		return NULL;
145 
146 	tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_PCI);
147 	if (!tunnel)
148 		return NULL;
149 
150 	tunnel->activate = tb_pci_activate;
151 	tunnel->src_port = down;
152 
153 	/*
154 	 * Discover both paths even if they are not complete. We will
155 	 * clean them up by calling tb_tunnel_deactivate() below in that
156 	 * case.
157 	 */
158 	path = tb_path_discover(down, TB_PCI_HOPID, NULL, -1,
159 				&tunnel->dst_port, "PCIe Up");
160 	if (!path) {
161 		/* Just disable the downstream port */
162 		tb_pci_port_enable(down, false);
163 		goto err_free;
164 	}
165 	tunnel->paths[TB_PCI_PATH_UP] = path;
166 	tb_pci_init_path(tunnel->paths[TB_PCI_PATH_UP]);
167 
168 	path = tb_path_discover(tunnel->dst_port, -1, down, TB_PCI_HOPID, NULL,
169 				"PCIe Down");
170 	if (!path)
171 		goto err_deactivate;
172 	tunnel->paths[TB_PCI_PATH_DOWN] = path;
173 	tb_pci_init_path(tunnel->paths[TB_PCI_PATH_DOWN]);
174 
175 	/* Validate that the tunnel is complete */
176 	if (!tb_port_is_pcie_up(tunnel->dst_port)) {
177 		tb_port_warn(tunnel->dst_port,
178 			     "path does not end on a PCIe adapter, cleaning up\n");
179 		goto err_deactivate;
180 	}
181 
182 	if (down != tunnel->src_port) {
183 		tb_tunnel_warn(tunnel, "path is not complete, cleaning up\n");
184 		goto err_deactivate;
185 	}
186 
187 	if (!tb_pci_port_is_enabled(tunnel->dst_port)) {
188 		tb_tunnel_warn(tunnel,
189 			       "tunnel is not fully activated, cleaning up\n");
190 		goto err_deactivate;
191 	}
192 
193 	tb_tunnel_dbg(tunnel, "discovered\n");
194 	return tunnel;
195 
196 err_deactivate:
197 	tb_tunnel_deactivate(tunnel);
198 err_free:
199 	tb_tunnel_free(tunnel);
200 
201 	return NULL;
202 }
203 
204 /**
205  * tb_tunnel_alloc_pci() - allocate a pci tunnel
206  * @tb: Pointer to the domain structure
207  * @up: PCIe upstream adapter port
208  * @down: PCIe downstream adapter port
209  *
210  * Allocate a PCI tunnel. The ports must be of type TB_TYPE_PCIE_UP and
211  * TB_TYPE_PCIE_DOWN.
212  *
213  * Return: Returns a tb_tunnel on success or NULL on failure.
214  */
215 struct tb_tunnel *tb_tunnel_alloc_pci(struct tb *tb, struct tb_port *up,
216 				      struct tb_port *down)
217 {
218 	struct tb_tunnel *tunnel;
219 	struct tb_path *path;
220 
221 	tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_PCI);
222 	if (!tunnel)
223 		return NULL;
224 
225 	tunnel->activate = tb_pci_activate;
226 	tunnel->src_port = down;
227 	tunnel->dst_port = up;
228 
229 	path = tb_path_alloc(tb, down, TB_PCI_HOPID, up, TB_PCI_HOPID, 0,
230 			     "PCIe Down");
231 	if (!path) {
232 		tb_tunnel_free(tunnel);
233 		return NULL;
234 	}
235 	tb_pci_init_path(path);
236 	tunnel->paths[TB_PCI_PATH_DOWN] = path;
237 
238 	path = tb_path_alloc(tb, up, TB_PCI_HOPID, down, TB_PCI_HOPID, 0,
239 			     "PCIe Up");
240 	if (!path) {
241 		tb_tunnel_free(tunnel);
242 		return NULL;
243 	}
244 	tb_pci_init_path(path);
245 	tunnel->paths[TB_PCI_PATH_UP] = path;
246 
247 	return tunnel;
248 }
249 
250 static bool tb_dp_is_usb4(const struct tb_switch *sw)
251 {
252 	/* Titan Ridge DP adapters need the same treatment as USB4 */
253 	return tb_switch_is_usb4(sw) || tb_switch_is_titan_ridge(sw);
254 }
255 
256 static int tb_dp_cm_handshake(struct tb_port *in, struct tb_port *out)
257 {
258 	int timeout = 10;
259 	u32 val;
260 	int ret;
261 
262 	/* Both ends need to support this */
263 	if (!tb_dp_is_usb4(in->sw) || !tb_dp_is_usb4(out->sw))
264 		return 0;
265 
266 	ret = tb_port_read(out, &val, TB_CFG_PORT,
267 			   out->cap_adap + DP_STATUS_CTRL, 1);
268 	if (ret)
269 		return ret;
270 
271 	val |= DP_STATUS_CTRL_UF | DP_STATUS_CTRL_CMHS;
272 
273 	ret = tb_port_write(out, &val, TB_CFG_PORT,
274 			    out->cap_adap + DP_STATUS_CTRL, 1);
275 	if (ret)
276 		return ret;
277 
278 	do {
279 		ret = tb_port_read(out, &val, TB_CFG_PORT,
280 				   out->cap_adap + DP_STATUS_CTRL, 1);
281 		if (ret)
282 			return ret;
283 		if (!(val & DP_STATUS_CTRL_CMHS))
284 			return 0;
285 		usleep_range(10, 100);
286 	} while (timeout--);
287 
288 	return -ETIMEDOUT;
289 }
290 
291 static inline u32 tb_dp_cap_get_rate(u32 val)
292 {
293 	u32 rate = (val & DP_COMMON_CAP_RATE_MASK) >> DP_COMMON_CAP_RATE_SHIFT;
294 
295 	switch (rate) {
296 	case DP_COMMON_CAP_RATE_RBR:
297 		return 1620;
298 	case DP_COMMON_CAP_RATE_HBR:
299 		return 2700;
300 	case DP_COMMON_CAP_RATE_HBR2:
301 		return 5400;
302 	case DP_COMMON_CAP_RATE_HBR3:
303 		return 8100;
304 	default:
305 		return 0;
306 	}
307 }
308 
309 static inline u32 tb_dp_cap_set_rate(u32 val, u32 rate)
310 {
311 	val &= ~DP_COMMON_CAP_RATE_MASK;
312 	switch (rate) {
313 	default:
314 		WARN(1, "invalid rate %u passed, defaulting to 1620 MB/s\n", rate);
315 		fallthrough;
316 	case 1620:
317 		val |= DP_COMMON_CAP_RATE_RBR << DP_COMMON_CAP_RATE_SHIFT;
318 		break;
319 	case 2700:
320 		val |= DP_COMMON_CAP_RATE_HBR << DP_COMMON_CAP_RATE_SHIFT;
321 		break;
322 	case 5400:
323 		val |= DP_COMMON_CAP_RATE_HBR2 << DP_COMMON_CAP_RATE_SHIFT;
324 		break;
325 	case 8100:
326 		val |= DP_COMMON_CAP_RATE_HBR3 << DP_COMMON_CAP_RATE_SHIFT;
327 		break;
328 	}
329 	return val;
330 }
331 
332 static inline u32 tb_dp_cap_get_lanes(u32 val)
333 {
334 	u32 lanes = (val & DP_COMMON_CAP_LANES_MASK) >> DP_COMMON_CAP_LANES_SHIFT;
335 
336 	switch (lanes) {
337 	case DP_COMMON_CAP_1_LANE:
338 		return 1;
339 	case DP_COMMON_CAP_2_LANES:
340 		return 2;
341 	case DP_COMMON_CAP_4_LANES:
342 		return 4;
343 	default:
344 		return 0;
345 	}
346 }
347 
348 static inline u32 tb_dp_cap_set_lanes(u32 val, u32 lanes)
349 {
350 	val &= ~DP_COMMON_CAP_LANES_MASK;
351 	switch (lanes) {
352 	default:
353 		WARN(1, "invalid number of lanes %u passed, defaulting to 1\n",
354 		     lanes);
355 		fallthrough;
356 	case 1:
357 		val |= DP_COMMON_CAP_1_LANE << DP_COMMON_CAP_LANES_SHIFT;
358 		break;
359 	case 2:
360 		val |= DP_COMMON_CAP_2_LANES << DP_COMMON_CAP_LANES_SHIFT;
361 		break;
362 	case 4:
363 		val |= DP_COMMON_CAP_4_LANES << DP_COMMON_CAP_LANES_SHIFT;
364 		break;
365 	}
366 	return val;
367 }
368 
369 static unsigned int tb_dp_bandwidth(unsigned int rate, unsigned int lanes)
370 {
371 	/* Tunneling removes the DP 8b/10b encoding */
372 	return rate * lanes * 8 / 10;
373 }
374 
375 static int tb_dp_reduce_bandwidth(int max_bw, u32 in_rate, u32 in_lanes,
376 				  u32 out_rate, u32 out_lanes, u32 *new_rate,
377 				  u32 *new_lanes)
378 {
379 	static const u32 dp_bw[][2] = {
380 		/* Mb/s, lanes */
381 		{ 8100, 4 }, /* 25920 Mb/s */
382 		{ 5400, 4 }, /* 17280 Mb/s */
383 		{ 8100, 2 }, /* 12960 Mb/s */
384 		{ 2700, 4 }, /* 8640 Mb/s */
385 		{ 5400, 2 }, /* 8640 Mb/s */
386 		{ 8100, 1 }, /* 6480 Mb/s */
387 		{ 1620, 4 }, /* 5184 Mb/s */
388 		{ 5400, 1 }, /* 4320 Mb/s */
389 		{ 2700, 2 }, /* 4320 Mb/s */
390 		{ 1620, 2 }, /* 2592 Mb/s */
391 		{ 2700, 1 }, /* 2160 Mb/s */
392 		{ 1620, 1 }, /* 1296 Mb/s */
393 	};
394 	unsigned int i;
395 
396 	/*
397 	 * Find a combination that can fit into max_bw and does not
398 	 * exceed the maximum rate and lanes supported by the DP OUT and
399 	 * DP IN adapters.
400 	 */
401 	for (i = 0; i < ARRAY_SIZE(dp_bw); i++) {
402 		if (dp_bw[i][0] > out_rate || dp_bw[i][1] > out_lanes)
403 			continue;
404 
405 		if (dp_bw[i][0] > in_rate || dp_bw[i][1] > in_lanes)
406 			continue;
407 
408 		if (tb_dp_bandwidth(dp_bw[i][0], dp_bw[i][1]) <= max_bw) {
409 			*new_rate = dp_bw[i][0];
410 			*new_lanes = dp_bw[i][1];
411 			return 0;
412 		}
413 	}
414 
415 	return -ENOSR;
416 }
417 
418 static int tb_dp_xchg_caps(struct tb_tunnel *tunnel)
419 {
420 	u32 out_dp_cap, out_rate, out_lanes, in_dp_cap, in_rate, in_lanes, bw;
421 	struct tb_port *out = tunnel->dst_port;
422 	struct tb_port *in = tunnel->src_port;
423 	int ret, max_bw;
424 
425 	/*
426 	 * Copy DP_LOCAL_CAP register to DP_REMOTE_CAP register for
427 	 * newer generation hardware.
428 	 */
429 	if (in->sw->generation < 2 || out->sw->generation < 2)
430 		return 0;
431 
432 	/*
433 	 * Perform connection manager handshake between IN and OUT ports
434 	 * before capabilities exchange can take place.
435 	 */
436 	ret = tb_dp_cm_handshake(in, out);
437 	if (ret)
438 		return ret;
439 
440 	/* Read both DP_LOCAL_CAP registers */
441 	ret = tb_port_read(in, &in_dp_cap, TB_CFG_PORT,
442 			   in->cap_adap + DP_LOCAL_CAP, 1);
443 	if (ret)
444 		return ret;
445 
446 	ret = tb_port_read(out, &out_dp_cap, TB_CFG_PORT,
447 			   out->cap_adap + DP_LOCAL_CAP, 1);
448 	if (ret)
449 		return ret;
450 
451 	/* Write IN local caps to OUT remote caps */
452 	ret = tb_port_write(out, &in_dp_cap, TB_CFG_PORT,
453 			    out->cap_adap + DP_REMOTE_CAP, 1);
454 	if (ret)
455 		return ret;
456 
457 	in_rate = tb_dp_cap_get_rate(in_dp_cap);
458 	in_lanes = tb_dp_cap_get_lanes(in_dp_cap);
459 	tb_port_dbg(in, "maximum supported bandwidth %u Mb/s x%u = %u Mb/s\n",
460 		    in_rate, in_lanes, tb_dp_bandwidth(in_rate, in_lanes));
461 
462 	/*
463 	 * If the tunnel bandwidth is limited (max_bw is set) then see
464 	 * if we need to reduce bandwidth to fit there.
465 	 */
466 	out_rate = tb_dp_cap_get_rate(out_dp_cap);
467 	out_lanes = tb_dp_cap_get_lanes(out_dp_cap);
468 	bw = tb_dp_bandwidth(out_rate, out_lanes);
469 	tb_port_dbg(out, "maximum supported bandwidth %u Mb/s x%u = %u Mb/s\n",
470 		    out_rate, out_lanes, bw);
471 
472 	if (in->sw->config.depth < out->sw->config.depth)
473 		max_bw = tunnel->max_down;
474 	else
475 		max_bw = tunnel->max_up;
476 
477 	if (max_bw && bw > max_bw) {
478 		u32 new_rate, new_lanes, new_bw;
479 
480 		ret = tb_dp_reduce_bandwidth(max_bw, in_rate, in_lanes,
481 					     out_rate, out_lanes, &new_rate,
482 					     &new_lanes);
483 		if (ret) {
484 			tb_port_info(out, "not enough bandwidth for DP tunnel\n");
485 			return ret;
486 		}
487 
488 		new_bw = tb_dp_bandwidth(new_rate, new_lanes);
489 		tb_port_dbg(out, "bandwidth reduced to %u Mb/s x%u = %u Mb/s\n",
490 			    new_rate, new_lanes, new_bw);
491 
492 		/*
493 		 * Set new rate and number of lanes before writing it to
494 		 * the IN port remote caps.
495 		 */
496 		out_dp_cap = tb_dp_cap_set_rate(out_dp_cap, new_rate);
497 		out_dp_cap = tb_dp_cap_set_lanes(out_dp_cap, new_lanes);
498 	}
499 
500 	return tb_port_write(in, &out_dp_cap, TB_CFG_PORT,
501 			     in->cap_adap + DP_REMOTE_CAP, 1);
502 }
503 
504 static int tb_dp_activate(struct tb_tunnel *tunnel, bool active)
505 {
506 	int ret;
507 
508 	if (active) {
509 		struct tb_path **paths;
510 		int last;
511 
512 		paths = tunnel->paths;
513 		last = paths[TB_DP_VIDEO_PATH_OUT]->path_length - 1;
514 
515 		tb_dp_port_set_hops(tunnel->src_port,
516 			paths[TB_DP_VIDEO_PATH_OUT]->hops[0].in_hop_index,
517 			paths[TB_DP_AUX_PATH_OUT]->hops[0].in_hop_index,
518 			paths[TB_DP_AUX_PATH_IN]->hops[last].next_hop_index);
519 
520 		tb_dp_port_set_hops(tunnel->dst_port,
521 			paths[TB_DP_VIDEO_PATH_OUT]->hops[last].next_hop_index,
522 			paths[TB_DP_AUX_PATH_IN]->hops[0].in_hop_index,
523 			paths[TB_DP_AUX_PATH_OUT]->hops[last].next_hop_index);
524 	} else {
525 		tb_dp_port_hpd_clear(tunnel->src_port);
526 		tb_dp_port_set_hops(tunnel->src_port, 0, 0, 0);
527 		if (tb_port_is_dpout(tunnel->dst_port))
528 			tb_dp_port_set_hops(tunnel->dst_port, 0, 0, 0);
529 	}
530 
531 	ret = tb_dp_port_enable(tunnel->src_port, active);
532 	if (ret)
533 		return ret;
534 
535 	if (tb_port_is_dpout(tunnel->dst_port))
536 		return tb_dp_port_enable(tunnel->dst_port, active);
537 
538 	return 0;
539 }
540 
541 static int tb_dp_consumed_bandwidth(struct tb_tunnel *tunnel, int *consumed_up,
542 				    int *consumed_down)
543 {
544 	struct tb_port *in = tunnel->src_port;
545 	const struct tb_switch *sw = in->sw;
546 	u32 val, rate = 0, lanes = 0;
547 	int ret;
548 
549 	if (tb_dp_is_usb4(sw)) {
550 		int timeout = 20;
551 
552 		/*
553 		 * Wait for DPRX done. Normally it should be already set
554 		 * for active tunnel.
555 		 */
556 		do {
557 			ret = tb_port_read(in, &val, TB_CFG_PORT,
558 					   in->cap_adap + DP_COMMON_CAP, 1);
559 			if (ret)
560 				return ret;
561 
562 			if (val & DP_COMMON_CAP_DPRX_DONE) {
563 				rate = tb_dp_cap_get_rate(val);
564 				lanes = tb_dp_cap_get_lanes(val);
565 				break;
566 			}
567 			msleep(250);
568 		} while (timeout--);
569 
570 		if (!timeout)
571 			return -ETIMEDOUT;
572 	} else if (sw->generation >= 2) {
573 		/*
574 		 * Read from the copied remote cap so that we take into
575 		 * account if capabilities were reduced during exchange.
576 		 */
577 		ret = tb_port_read(in, &val, TB_CFG_PORT,
578 				   in->cap_adap + DP_REMOTE_CAP, 1);
579 		if (ret)
580 			return ret;
581 
582 		rate = tb_dp_cap_get_rate(val);
583 		lanes = tb_dp_cap_get_lanes(val);
584 	} else {
585 		/* No bandwidth management for legacy devices  */
586 		*consumed_up = 0;
587 		*consumed_down = 0;
588 		return 0;
589 	}
590 
591 	if (in->sw->config.depth < tunnel->dst_port->sw->config.depth) {
592 		*consumed_up = 0;
593 		*consumed_down = tb_dp_bandwidth(rate, lanes);
594 	} else {
595 		*consumed_up = tb_dp_bandwidth(rate, lanes);
596 		*consumed_down = 0;
597 	}
598 
599 	return 0;
600 }
601 
602 static void tb_dp_init_aux_path(struct tb_path *path)
603 {
604 	int i;
605 
606 	path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
607 	path->egress_shared_buffer = TB_PATH_NONE;
608 	path->ingress_fc_enable = TB_PATH_ALL;
609 	path->ingress_shared_buffer = TB_PATH_NONE;
610 	path->priority = 2;
611 	path->weight = 1;
612 
613 	for (i = 0; i < path->path_length; i++)
614 		path->hops[i].initial_credits = 1;
615 }
616 
617 static void tb_dp_init_video_path(struct tb_path *path, bool discover)
618 {
619 	u32 nfc_credits = path->hops[0].in_port->config.nfc_credits;
620 
621 	path->egress_fc_enable = TB_PATH_NONE;
622 	path->egress_shared_buffer = TB_PATH_NONE;
623 	path->ingress_fc_enable = TB_PATH_NONE;
624 	path->ingress_shared_buffer = TB_PATH_NONE;
625 	path->priority = 1;
626 	path->weight = 1;
627 
628 	if (discover) {
629 		path->nfc_credits = nfc_credits & ADP_CS_4_NFC_BUFFERS_MASK;
630 	} else {
631 		u32 max_credits;
632 
633 		max_credits = (nfc_credits & ADP_CS_4_TOTAL_BUFFERS_MASK) >>
634 			ADP_CS_4_TOTAL_BUFFERS_SHIFT;
635 		/* Leave some credits for AUX path */
636 		path->nfc_credits = min(max_credits - 2, 12U);
637 	}
638 }
639 
640 /**
641  * tb_tunnel_discover_dp() - Discover existing Display Port tunnels
642  * @tb: Pointer to the domain structure
643  * @in: DP in adapter
644  *
645  * If @in adapter is active, follows the tunnel to the DP out adapter
646  * and back. Returns the discovered tunnel or %NULL if there was no
647  * tunnel.
648  *
649  * Return: DP tunnel or %NULL if no tunnel found.
650  */
651 struct tb_tunnel *tb_tunnel_discover_dp(struct tb *tb, struct tb_port *in)
652 {
653 	struct tb_tunnel *tunnel;
654 	struct tb_port *port;
655 	struct tb_path *path;
656 
657 	if (!tb_dp_port_is_enabled(in))
658 		return NULL;
659 
660 	tunnel = tb_tunnel_alloc(tb, 3, TB_TUNNEL_DP);
661 	if (!tunnel)
662 		return NULL;
663 
664 	tunnel->init = tb_dp_xchg_caps;
665 	tunnel->activate = tb_dp_activate;
666 	tunnel->consumed_bandwidth = tb_dp_consumed_bandwidth;
667 	tunnel->src_port = in;
668 
669 	path = tb_path_discover(in, TB_DP_VIDEO_HOPID, NULL, -1,
670 				&tunnel->dst_port, "Video");
671 	if (!path) {
672 		/* Just disable the DP IN port */
673 		tb_dp_port_enable(in, false);
674 		goto err_free;
675 	}
676 	tunnel->paths[TB_DP_VIDEO_PATH_OUT] = path;
677 	tb_dp_init_video_path(tunnel->paths[TB_DP_VIDEO_PATH_OUT], true);
678 
679 	path = tb_path_discover(in, TB_DP_AUX_TX_HOPID, NULL, -1, NULL, "AUX TX");
680 	if (!path)
681 		goto err_deactivate;
682 	tunnel->paths[TB_DP_AUX_PATH_OUT] = path;
683 	tb_dp_init_aux_path(tunnel->paths[TB_DP_AUX_PATH_OUT]);
684 
685 	path = tb_path_discover(tunnel->dst_port, -1, in, TB_DP_AUX_RX_HOPID,
686 				&port, "AUX RX");
687 	if (!path)
688 		goto err_deactivate;
689 	tunnel->paths[TB_DP_AUX_PATH_IN] = path;
690 	tb_dp_init_aux_path(tunnel->paths[TB_DP_AUX_PATH_IN]);
691 
692 	/* Validate that the tunnel is complete */
693 	if (!tb_port_is_dpout(tunnel->dst_port)) {
694 		tb_port_warn(in, "path does not end on a DP adapter, cleaning up\n");
695 		goto err_deactivate;
696 	}
697 
698 	if (!tb_dp_port_is_enabled(tunnel->dst_port))
699 		goto err_deactivate;
700 
701 	if (!tb_dp_port_hpd_is_active(tunnel->dst_port))
702 		goto err_deactivate;
703 
704 	if (port != tunnel->src_port) {
705 		tb_tunnel_warn(tunnel, "path is not complete, cleaning up\n");
706 		goto err_deactivate;
707 	}
708 
709 	tb_tunnel_dbg(tunnel, "discovered\n");
710 	return tunnel;
711 
712 err_deactivate:
713 	tb_tunnel_deactivate(tunnel);
714 err_free:
715 	tb_tunnel_free(tunnel);
716 
717 	return NULL;
718 }
719 
720 /**
721  * tb_tunnel_alloc_dp() - allocate a Display Port tunnel
722  * @tb: Pointer to the domain structure
723  * @in: DP in adapter port
724  * @out: DP out adapter port
725  * @max_up: Maximum available upstream bandwidth for the DP tunnel (%0
726  *	    if not limited)
727  * @max_down: Maximum available downstream bandwidth for the DP tunnel
728  *	      (%0 if not limited)
729  *
730  * Allocates a tunnel between @in and @out that is capable of tunneling
731  * Display Port traffic.
732  *
733  * Return: Returns a tb_tunnel on success or NULL on failure.
734  */
735 struct tb_tunnel *tb_tunnel_alloc_dp(struct tb *tb, struct tb_port *in,
736 				     struct tb_port *out, int max_up,
737 				     int max_down)
738 {
739 	struct tb_tunnel *tunnel;
740 	struct tb_path **paths;
741 	struct tb_path *path;
742 
743 	if (WARN_ON(!in->cap_adap || !out->cap_adap))
744 		return NULL;
745 
746 	tunnel = tb_tunnel_alloc(tb, 3, TB_TUNNEL_DP);
747 	if (!tunnel)
748 		return NULL;
749 
750 	tunnel->init = tb_dp_xchg_caps;
751 	tunnel->activate = tb_dp_activate;
752 	tunnel->consumed_bandwidth = tb_dp_consumed_bandwidth;
753 	tunnel->src_port = in;
754 	tunnel->dst_port = out;
755 	tunnel->max_up = max_up;
756 	tunnel->max_down = max_down;
757 
758 	paths = tunnel->paths;
759 
760 	path = tb_path_alloc(tb, in, TB_DP_VIDEO_HOPID, out, TB_DP_VIDEO_HOPID,
761 			     1, "Video");
762 	if (!path)
763 		goto err_free;
764 	tb_dp_init_video_path(path, false);
765 	paths[TB_DP_VIDEO_PATH_OUT] = path;
766 
767 	path = tb_path_alloc(tb, in, TB_DP_AUX_TX_HOPID, out,
768 			     TB_DP_AUX_TX_HOPID, 1, "AUX TX");
769 	if (!path)
770 		goto err_free;
771 	tb_dp_init_aux_path(path);
772 	paths[TB_DP_AUX_PATH_OUT] = path;
773 
774 	path = tb_path_alloc(tb, out, TB_DP_AUX_RX_HOPID, in,
775 			     TB_DP_AUX_RX_HOPID, 1, "AUX RX");
776 	if (!path)
777 		goto err_free;
778 	tb_dp_init_aux_path(path);
779 	paths[TB_DP_AUX_PATH_IN] = path;
780 
781 	return tunnel;
782 
783 err_free:
784 	tb_tunnel_free(tunnel);
785 	return NULL;
786 }
787 
788 static u32 tb_dma_credits(struct tb_port *nhi)
789 {
790 	u32 max_credits;
791 
792 	max_credits = (nhi->config.nfc_credits & ADP_CS_4_TOTAL_BUFFERS_MASK) >>
793 		ADP_CS_4_TOTAL_BUFFERS_SHIFT;
794 	return min(max_credits, 13U);
795 }
796 
797 static void tb_dma_init_path(struct tb_path *path, unsigned int efc, u32 credits)
798 {
799 	int i;
800 
801 	path->egress_fc_enable = efc;
802 	path->ingress_fc_enable = TB_PATH_ALL;
803 	path->egress_shared_buffer = TB_PATH_NONE;
804 	path->ingress_shared_buffer = TB_PATH_NONE;
805 	path->priority = 5;
806 	path->weight = 1;
807 	path->clear_fc = true;
808 
809 	for (i = 0; i < path->path_length; i++)
810 		path->hops[i].initial_credits = credits;
811 }
812 
813 /**
814  * tb_tunnel_alloc_dma() - allocate a DMA tunnel
815  * @tb: Pointer to the domain structure
816  * @nhi: Host controller port
817  * @dst: Destination null port which the other domain is connected to
818  * @transmit_path: HopID used for transmitting packets
819  * @transmit_ring: NHI ring number used to send packets towards the
820  *		   other domain. Set to %-1 if TX path is not needed.
821  * @receive_path: HopID used for receiving packets
822  * @receive_ring: NHI ring number used to receive packets from the
823  *		  other domain. Set to %-1 if RX path is not needed.
824  *
825  * Return: Returns a tb_tunnel on success or NULL on failure.
826  */
827 struct tb_tunnel *tb_tunnel_alloc_dma(struct tb *tb, struct tb_port *nhi,
828 				      struct tb_port *dst, int transmit_path,
829 				      int transmit_ring, int receive_path,
830 				      int receive_ring)
831 {
832 	struct tb_tunnel *tunnel;
833 	size_t npaths = 0, i = 0;
834 	struct tb_path *path;
835 	u32 credits;
836 
837 	if (receive_ring > 0)
838 		npaths++;
839 	if (transmit_ring > 0)
840 		npaths++;
841 
842 	if (WARN_ON(!npaths))
843 		return NULL;
844 
845 	tunnel = tb_tunnel_alloc(tb, npaths, TB_TUNNEL_DMA);
846 	if (!tunnel)
847 		return NULL;
848 
849 	tunnel->src_port = nhi;
850 	tunnel->dst_port = dst;
851 
852 	credits = tb_dma_credits(nhi);
853 
854 	if (receive_ring > 0) {
855 		path = tb_path_alloc(tb, dst, receive_path, nhi, receive_ring, 0,
856 				     "DMA RX");
857 		if (!path) {
858 			tb_tunnel_free(tunnel);
859 			return NULL;
860 		}
861 		tb_dma_init_path(path, TB_PATH_SOURCE | TB_PATH_INTERNAL, credits);
862 		tunnel->paths[i++] = path;
863 	}
864 
865 	if (transmit_ring > 0) {
866 		path = tb_path_alloc(tb, nhi, transmit_ring, dst, transmit_path, 0,
867 				     "DMA TX");
868 		if (!path) {
869 			tb_tunnel_free(tunnel);
870 			return NULL;
871 		}
872 		tb_dma_init_path(path, TB_PATH_ALL, credits);
873 		tunnel->paths[i++] = path;
874 	}
875 
876 	return tunnel;
877 }
878 
879 /**
880  * tb_tunnel_match_dma() - Match DMA tunnel
881  * @tunnel: Tunnel to match
882  * @transmit_path: HopID used for transmitting packets. Pass %-1 to ignore.
883  * @transmit_ring: NHI ring number used to send packets towards the
884  *		   other domain. Pass %-1 to ignore.
885  * @receive_path: HopID used for receiving packets. Pass %-1 to ignore.
886  * @receive_ring: NHI ring number used to receive packets from the
887  *		  other domain. Pass %-1 to ignore.
888  *
889  * This function can be used to match specific DMA tunnel, if there are
890  * multiple DMA tunnels going through the same XDomain connection.
891  * Returns true if there is match and false otherwise.
892  */
893 bool tb_tunnel_match_dma(const struct tb_tunnel *tunnel, int transmit_path,
894 			 int transmit_ring, int receive_path, int receive_ring)
895 {
896 	const struct tb_path *tx_path = NULL, *rx_path = NULL;
897 	int i;
898 
899 	if (!receive_ring || !transmit_ring)
900 		return false;
901 
902 	for (i = 0; i < tunnel->npaths; i++) {
903 		const struct tb_path *path = tunnel->paths[i];
904 
905 		if (!path)
906 			continue;
907 
908 		if (tb_port_is_nhi(path->hops[0].in_port))
909 			tx_path = path;
910 		else if (tb_port_is_nhi(path->hops[path->path_length - 1].out_port))
911 			rx_path = path;
912 	}
913 
914 	if (transmit_ring > 0 || transmit_path > 0) {
915 		if (!tx_path)
916 			return false;
917 		if (transmit_ring > 0 &&
918 		    (tx_path->hops[0].in_hop_index != transmit_ring))
919 			return false;
920 		if (transmit_path > 0 &&
921 		    (tx_path->hops[tx_path->path_length - 1].next_hop_index != transmit_path))
922 			return false;
923 	}
924 
925 	if (receive_ring > 0 || receive_path > 0) {
926 		if (!rx_path)
927 			return false;
928 		if (receive_path > 0 &&
929 		    (rx_path->hops[0].in_hop_index != receive_path))
930 			return false;
931 		if (receive_ring > 0 &&
932 		    (rx_path->hops[rx_path->path_length - 1].next_hop_index != receive_ring))
933 			return false;
934 	}
935 
936 	return true;
937 }
938 
939 static int tb_usb3_max_link_rate(struct tb_port *up, struct tb_port *down)
940 {
941 	int ret, up_max_rate, down_max_rate;
942 
943 	ret = usb4_usb3_port_max_link_rate(up);
944 	if (ret < 0)
945 		return ret;
946 	up_max_rate = ret;
947 
948 	ret = usb4_usb3_port_max_link_rate(down);
949 	if (ret < 0)
950 		return ret;
951 	down_max_rate = ret;
952 
953 	return min(up_max_rate, down_max_rate);
954 }
955 
956 static int tb_usb3_init(struct tb_tunnel *tunnel)
957 {
958 	tb_tunnel_dbg(tunnel, "allocating initial bandwidth %d/%d Mb/s\n",
959 		      tunnel->allocated_up, tunnel->allocated_down);
960 
961 	return usb4_usb3_port_allocate_bandwidth(tunnel->src_port,
962 						 &tunnel->allocated_up,
963 						 &tunnel->allocated_down);
964 }
965 
966 static int tb_usb3_activate(struct tb_tunnel *tunnel, bool activate)
967 {
968 	int res;
969 
970 	res = tb_usb3_port_enable(tunnel->src_port, activate);
971 	if (res)
972 		return res;
973 
974 	if (tb_port_is_usb3_up(tunnel->dst_port))
975 		return tb_usb3_port_enable(tunnel->dst_port, activate);
976 
977 	return 0;
978 }
979 
980 static int tb_usb3_consumed_bandwidth(struct tb_tunnel *tunnel,
981 		int *consumed_up, int *consumed_down)
982 {
983 	int pcie_enabled = tb_acpi_may_tunnel_pcie();
984 
985 	/*
986 	 * PCIe tunneling, if enabled, affects the USB3 bandwidth so
987 	 * take that it into account here.
988 	 */
989 	*consumed_up = tunnel->allocated_up * (3 + pcie_enabled) / 3;
990 	*consumed_down = tunnel->allocated_down * (3 + pcie_enabled) / 3;
991 	return 0;
992 }
993 
994 static int tb_usb3_release_unused_bandwidth(struct tb_tunnel *tunnel)
995 {
996 	int ret;
997 
998 	ret = usb4_usb3_port_release_bandwidth(tunnel->src_port,
999 					       &tunnel->allocated_up,
1000 					       &tunnel->allocated_down);
1001 	if (ret)
1002 		return ret;
1003 
1004 	tb_tunnel_dbg(tunnel, "decreased bandwidth allocation to %d/%d Mb/s\n",
1005 		      tunnel->allocated_up, tunnel->allocated_down);
1006 	return 0;
1007 }
1008 
1009 static void tb_usb3_reclaim_available_bandwidth(struct tb_tunnel *tunnel,
1010 						int *available_up,
1011 						int *available_down)
1012 {
1013 	int ret, max_rate, allocate_up, allocate_down;
1014 
1015 	ret = usb4_usb3_port_actual_link_rate(tunnel->src_port);
1016 	if (ret < 0) {
1017 		tb_tunnel_warn(tunnel, "failed to read actual link rate\n");
1018 		return;
1019 	} else if (!ret) {
1020 		/* Use maximum link rate if the link valid is not set */
1021 		ret = usb4_usb3_port_max_link_rate(tunnel->src_port);
1022 		if (ret < 0) {
1023 			tb_tunnel_warn(tunnel, "failed to read maximum link rate\n");
1024 			return;
1025 		}
1026 	}
1027 
1028 	/*
1029 	 * 90% of the max rate can be allocated for isochronous
1030 	 * transfers.
1031 	 */
1032 	max_rate = ret * 90 / 100;
1033 
1034 	/* No need to reclaim if already at maximum */
1035 	if (tunnel->allocated_up >= max_rate &&
1036 	    tunnel->allocated_down >= max_rate)
1037 		return;
1038 
1039 	/* Don't go lower than what is already allocated */
1040 	allocate_up = min(max_rate, *available_up);
1041 	if (allocate_up < tunnel->allocated_up)
1042 		allocate_up = tunnel->allocated_up;
1043 
1044 	allocate_down = min(max_rate, *available_down);
1045 	if (allocate_down < tunnel->allocated_down)
1046 		allocate_down = tunnel->allocated_down;
1047 
1048 	/* If no changes no need to do more */
1049 	if (allocate_up == tunnel->allocated_up &&
1050 	    allocate_down == tunnel->allocated_down)
1051 		return;
1052 
1053 	ret = usb4_usb3_port_allocate_bandwidth(tunnel->src_port, &allocate_up,
1054 						&allocate_down);
1055 	if (ret) {
1056 		tb_tunnel_info(tunnel, "failed to allocate bandwidth\n");
1057 		return;
1058 	}
1059 
1060 	tunnel->allocated_up = allocate_up;
1061 	*available_up -= tunnel->allocated_up;
1062 
1063 	tunnel->allocated_down = allocate_down;
1064 	*available_down -= tunnel->allocated_down;
1065 
1066 	tb_tunnel_dbg(tunnel, "increased bandwidth allocation to %d/%d Mb/s\n",
1067 		      tunnel->allocated_up, tunnel->allocated_down);
1068 }
1069 
1070 static void tb_usb3_init_path(struct tb_path *path)
1071 {
1072 	path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
1073 	path->egress_shared_buffer = TB_PATH_NONE;
1074 	path->ingress_fc_enable = TB_PATH_ALL;
1075 	path->ingress_shared_buffer = TB_PATH_NONE;
1076 	path->priority = 3;
1077 	path->weight = 3;
1078 	path->drop_packages = 0;
1079 	path->nfc_credits = 0;
1080 	path->hops[0].initial_credits = 7;
1081 	if (path->path_length > 1)
1082 		path->hops[1].initial_credits =
1083 			tb_initial_credits(path->hops[1].in_port->sw);
1084 }
1085 
1086 /**
1087  * tb_tunnel_discover_usb3() - Discover existing USB3 tunnels
1088  * @tb: Pointer to the domain structure
1089  * @down: USB3 downstream adapter
1090  *
1091  * If @down adapter is active, follows the tunnel to the USB3 upstream
1092  * adapter and back. Returns the discovered tunnel or %NULL if there was
1093  * no tunnel.
1094  */
1095 struct tb_tunnel *tb_tunnel_discover_usb3(struct tb *tb, struct tb_port *down)
1096 {
1097 	struct tb_tunnel *tunnel;
1098 	struct tb_path *path;
1099 
1100 	if (!tb_usb3_port_is_enabled(down))
1101 		return NULL;
1102 
1103 	tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_USB3);
1104 	if (!tunnel)
1105 		return NULL;
1106 
1107 	tunnel->activate = tb_usb3_activate;
1108 	tunnel->src_port = down;
1109 
1110 	/*
1111 	 * Discover both paths even if they are not complete. We will
1112 	 * clean them up by calling tb_tunnel_deactivate() below in that
1113 	 * case.
1114 	 */
1115 	path = tb_path_discover(down, TB_USB3_HOPID, NULL, -1,
1116 				&tunnel->dst_port, "USB3 Down");
1117 	if (!path) {
1118 		/* Just disable the downstream port */
1119 		tb_usb3_port_enable(down, false);
1120 		goto err_free;
1121 	}
1122 	tunnel->paths[TB_USB3_PATH_DOWN] = path;
1123 	tb_usb3_init_path(tunnel->paths[TB_USB3_PATH_DOWN]);
1124 
1125 	path = tb_path_discover(tunnel->dst_port, -1, down, TB_USB3_HOPID, NULL,
1126 				"USB3 Up");
1127 	if (!path)
1128 		goto err_deactivate;
1129 	tunnel->paths[TB_USB3_PATH_UP] = path;
1130 	tb_usb3_init_path(tunnel->paths[TB_USB3_PATH_UP]);
1131 
1132 	/* Validate that the tunnel is complete */
1133 	if (!tb_port_is_usb3_up(tunnel->dst_port)) {
1134 		tb_port_warn(tunnel->dst_port,
1135 			     "path does not end on an USB3 adapter, cleaning up\n");
1136 		goto err_deactivate;
1137 	}
1138 
1139 	if (down != tunnel->src_port) {
1140 		tb_tunnel_warn(tunnel, "path is not complete, cleaning up\n");
1141 		goto err_deactivate;
1142 	}
1143 
1144 	if (!tb_usb3_port_is_enabled(tunnel->dst_port)) {
1145 		tb_tunnel_warn(tunnel,
1146 			       "tunnel is not fully activated, cleaning up\n");
1147 		goto err_deactivate;
1148 	}
1149 
1150 	if (!tb_route(down->sw)) {
1151 		int ret;
1152 
1153 		/*
1154 		 * Read the initial bandwidth allocation for the first
1155 		 * hop tunnel.
1156 		 */
1157 		ret = usb4_usb3_port_allocated_bandwidth(down,
1158 			&tunnel->allocated_up, &tunnel->allocated_down);
1159 		if (ret)
1160 			goto err_deactivate;
1161 
1162 		tb_tunnel_dbg(tunnel, "currently allocated bandwidth %d/%d Mb/s\n",
1163 			      tunnel->allocated_up, tunnel->allocated_down);
1164 
1165 		tunnel->init = tb_usb3_init;
1166 		tunnel->consumed_bandwidth = tb_usb3_consumed_bandwidth;
1167 		tunnel->release_unused_bandwidth =
1168 			tb_usb3_release_unused_bandwidth;
1169 		tunnel->reclaim_available_bandwidth =
1170 			tb_usb3_reclaim_available_bandwidth;
1171 	}
1172 
1173 	tb_tunnel_dbg(tunnel, "discovered\n");
1174 	return tunnel;
1175 
1176 err_deactivate:
1177 	tb_tunnel_deactivate(tunnel);
1178 err_free:
1179 	tb_tunnel_free(tunnel);
1180 
1181 	return NULL;
1182 }
1183 
1184 /**
1185  * tb_tunnel_alloc_usb3() - allocate a USB3 tunnel
1186  * @tb: Pointer to the domain structure
1187  * @up: USB3 upstream adapter port
1188  * @down: USB3 downstream adapter port
1189  * @max_up: Maximum available upstream bandwidth for the USB3 tunnel (%0
1190  *	    if not limited).
1191  * @max_down: Maximum available downstream bandwidth for the USB3 tunnel
1192  *	      (%0 if not limited).
1193  *
1194  * Allocate an USB3 tunnel. The ports must be of type @TB_TYPE_USB3_UP and
1195  * @TB_TYPE_USB3_DOWN.
1196  *
1197  * Return: Returns a tb_tunnel on success or %NULL on failure.
1198  */
1199 struct tb_tunnel *tb_tunnel_alloc_usb3(struct tb *tb, struct tb_port *up,
1200 				       struct tb_port *down, int max_up,
1201 				       int max_down)
1202 {
1203 	struct tb_tunnel *tunnel;
1204 	struct tb_path *path;
1205 	int max_rate = 0;
1206 
1207 	/*
1208 	 * Check that we have enough bandwidth available for the new
1209 	 * USB3 tunnel.
1210 	 */
1211 	if (max_up > 0 || max_down > 0) {
1212 		max_rate = tb_usb3_max_link_rate(down, up);
1213 		if (max_rate < 0)
1214 			return NULL;
1215 
1216 		/* Only 90% can be allocated for USB3 isochronous transfers */
1217 		max_rate = max_rate * 90 / 100;
1218 		tb_port_dbg(up, "required bandwidth for USB3 tunnel %d Mb/s\n",
1219 			    max_rate);
1220 
1221 		if (max_rate > max_up || max_rate > max_down) {
1222 			tb_port_warn(up, "not enough bandwidth for USB3 tunnel\n");
1223 			return NULL;
1224 		}
1225 	}
1226 
1227 	tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_USB3);
1228 	if (!tunnel)
1229 		return NULL;
1230 
1231 	tunnel->activate = tb_usb3_activate;
1232 	tunnel->src_port = down;
1233 	tunnel->dst_port = up;
1234 	tunnel->max_up = max_up;
1235 	tunnel->max_down = max_down;
1236 
1237 	path = tb_path_alloc(tb, down, TB_USB3_HOPID, up, TB_USB3_HOPID, 0,
1238 			     "USB3 Down");
1239 	if (!path) {
1240 		tb_tunnel_free(tunnel);
1241 		return NULL;
1242 	}
1243 	tb_usb3_init_path(path);
1244 	tunnel->paths[TB_USB3_PATH_DOWN] = path;
1245 
1246 	path = tb_path_alloc(tb, up, TB_USB3_HOPID, down, TB_USB3_HOPID, 0,
1247 			     "USB3 Up");
1248 	if (!path) {
1249 		tb_tunnel_free(tunnel);
1250 		return NULL;
1251 	}
1252 	tb_usb3_init_path(path);
1253 	tunnel->paths[TB_USB3_PATH_UP] = path;
1254 
1255 	if (!tb_route(down->sw)) {
1256 		tunnel->allocated_up = max_rate;
1257 		tunnel->allocated_down = max_rate;
1258 
1259 		tunnel->init = tb_usb3_init;
1260 		tunnel->consumed_bandwidth = tb_usb3_consumed_bandwidth;
1261 		tunnel->release_unused_bandwidth =
1262 			tb_usb3_release_unused_bandwidth;
1263 		tunnel->reclaim_available_bandwidth =
1264 			tb_usb3_reclaim_available_bandwidth;
1265 	}
1266 
1267 	return tunnel;
1268 }
1269 
1270 /**
1271  * tb_tunnel_free() - free a tunnel
1272  * @tunnel: Tunnel to be freed
1273  *
1274  * Frees a tunnel. The tunnel does not need to be deactivated.
1275  */
1276 void tb_tunnel_free(struct tb_tunnel *tunnel)
1277 {
1278 	int i;
1279 
1280 	if (!tunnel)
1281 		return;
1282 
1283 	for (i = 0; i < tunnel->npaths; i++) {
1284 		if (tunnel->paths[i])
1285 			tb_path_free(tunnel->paths[i]);
1286 	}
1287 
1288 	kfree(tunnel->paths);
1289 	kfree(tunnel);
1290 }
1291 
1292 /**
1293  * tb_tunnel_is_invalid - check whether an activated path is still valid
1294  * @tunnel: Tunnel to check
1295  */
1296 bool tb_tunnel_is_invalid(struct tb_tunnel *tunnel)
1297 {
1298 	int i;
1299 
1300 	for (i = 0; i < tunnel->npaths; i++) {
1301 		WARN_ON(!tunnel->paths[i]->activated);
1302 		if (tb_path_is_invalid(tunnel->paths[i]))
1303 			return true;
1304 	}
1305 
1306 	return false;
1307 }
1308 
1309 /**
1310  * tb_tunnel_restart() - activate a tunnel after a hardware reset
1311  * @tunnel: Tunnel to restart
1312  *
1313  * Return: 0 on success and negative errno in case if failure
1314  */
1315 int tb_tunnel_restart(struct tb_tunnel *tunnel)
1316 {
1317 	int res, i;
1318 
1319 	tb_tunnel_dbg(tunnel, "activating\n");
1320 
1321 	/*
1322 	 * Make sure all paths are properly disabled before enabling
1323 	 * them again.
1324 	 */
1325 	for (i = 0; i < tunnel->npaths; i++) {
1326 		if (tunnel->paths[i]->activated) {
1327 			tb_path_deactivate(tunnel->paths[i]);
1328 			tunnel->paths[i]->activated = false;
1329 		}
1330 	}
1331 
1332 	if (tunnel->init) {
1333 		res = tunnel->init(tunnel);
1334 		if (res)
1335 			return res;
1336 	}
1337 
1338 	for (i = 0; i < tunnel->npaths; i++) {
1339 		res = tb_path_activate(tunnel->paths[i]);
1340 		if (res)
1341 			goto err;
1342 	}
1343 
1344 	if (tunnel->activate) {
1345 		res = tunnel->activate(tunnel, true);
1346 		if (res)
1347 			goto err;
1348 	}
1349 
1350 	return 0;
1351 
1352 err:
1353 	tb_tunnel_warn(tunnel, "activation failed\n");
1354 	tb_tunnel_deactivate(tunnel);
1355 	return res;
1356 }
1357 
1358 /**
1359  * tb_tunnel_activate() - activate a tunnel
1360  * @tunnel: Tunnel to activate
1361  *
1362  * Return: Returns 0 on success or an error code on failure.
1363  */
1364 int tb_tunnel_activate(struct tb_tunnel *tunnel)
1365 {
1366 	int i;
1367 
1368 	for (i = 0; i < tunnel->npaths; i++) {
1369 		if (tunnel->paths[i]->activated) {
1370 			tb_tunnel_WARN(tunnel,
1371 				       "trying to activate an already activated tunnel\n");
1372 			return -EINVAL;
1373 		}
1374 	}
1375 
1376 	return tb_tunnel_restart(tunnel);
1377 }
1378 
1379 /**
1380  * tb_tunnel_deactivate() - deactivate a tunnel
1381  * @tunnel: Tunnel to deactivate
1382  */
1383 void tb_tunnel_deactivate(struct tb_tunnel *tunnel)
1384 {
1385 	int i;
1386 
1387 	tb_tunnel_dbg(tunnel, "deactivating\n");
1388 
1389 	if (tunnel->activate)
1390 		tunnel->activate(tunnel, false);
1391 
1392 	for (i = 0; i < tunnel->npaths; i++) {
1393 		if (tunnel->paths[i] && tunnel->paths[i]->activated)
1394 			tb_path_deactivate(tunnel->paths[i]);
1395 	}
1396 }
1397 
1398 /**
1399  * tb_tunnel_port_on_path() - Does the tunnel go through port
1400  * @tunnel: Tunnel to check
1401  * @port: Port to check
1402  *
1403  * Returns true if @tunnel goes through @port (direction does not matter),
1404  * false otherwise.
1405  */
1406 bool tb_tunnel_port_on_path(const struct tb_tunnel *tunnel,
1407 			    const struct tb_port *port)
1408 {
1409 	int i;
1410 
1411 	for (i = 0; i < tunnel->npaths; i++) {
1412 		if (!tunnel->paths[i])
1413 			continue;
1414 
1415 		if (tb_path_port_on_path(tunnel->paths[i], port))
1416 			return true;
1417 	}
1418 
1419 	return false;
1420 }
1421 
1422 static bool tb_tunnel_is_active(const struct tb_tunnel *tunnel)
1423 {
1424 	int i;
1425 
1426 	for (i = 0; i < tunnel->npaths; i++) {
1427 		if (!tunnel->paths[i])
1428 			return false;
1429 		if (!tunnel->paths[i]->activated)
1430 			return false;
1431 	}
1432 
1433 	return true;
1434 }
1435 
1436 /**
1437  * tb_tunnel_consumed_bandwidth() - Return bandwidth consumed by the tunnel
1438  * @tunnel: Tunnel to check
1439  * @consumed_up: Consumed bandwidth in Mb/s from @dst_port to @src_port.
1440  *		 Can be %NULL.
1441  * @consumed_down: Consumed bandwidth in Mb/s from @src_port to @dst_port.
1442  *		   Can be %NULL.
1443  *
1444  * Stores the amount of isochronous bandwidth @tunnel consumes in
1445  * @consumed_up and @consumed_down. In case of success returns %0,
1446  * negative errno otherwise.
1447  */
1448 int tb_tunnel_consumed_bandwidth(struct tb_tunnel *tunnel, int *consumed_up,
1449 				 int *consumed_down)
1450 {
1451 	int up_bw = 0, down_bw = 0;
1452 
1453 	if (!tb_tunnel_is_active(tunnel))
1454 		goto out;
1455 
1456 	if (tunnel->consumed_bandwidth) {
1457 		int ret;
1458 
1459 		ret = tunnel->consumed_bandwidth(tunnel, &up_bw, &down_bw);
1460 		if (ret)
1461 			return ret;
1462 
1463 		tb_tunnel_dbg(tunnel, "consumed bandwidth %d/%d Mb/s\n", up_bw,
1464 			      down_bw);
1465 	}
1466 
1467 out:
1468 	if (consumed_up)
1469 		*consumed_up = up_bw;
1470 	if (consumed_down)
1471 		*consumed_down = down_bw;
1472 
1473 	return 0;
1474 }
1475 
1476 /**
1477  * tb_tunnel_release_unused_bandwidth() - Release unused bandwidth
1478  * @tunnel: Tunnel whose unused bandwidth to release
1479  *
1480  * If tunnel supports dynamic bandwidth management (USB3 tunnels at the
1481  * moment) this function makes it to release all the unused bandwidth.
1482  *
1483  * Returns %0 in case of success and negative errno otherwise.
1484  */
1485 int tb_tunnel_release_unused_bandwidth(struct tb_tunnel *tunnel)
1486 {
1487 	if (!tb_tunnel_is_active(tunnel))
1488 		return 0;
1489 
1490 	if (tunnel->release_unused_bandwidth) {
1491 		int ret;
1492 
1493 		ret = tunnel->release_unused_bandwidth(tunnel);
1494 		if (ret)
1495 			return ret;
1496 	}
1497 
1498 	return 0;
1499 }
1500 
1501 /**
1502  * tb_tunnel_reclaim_available_bandwidth() - Reclaim available bandwidth
1503  * @tunnel: Tunnel reclaiming available bandwidth
1504  * @available_up: Available upstream bandwidth (in Mb/s)
1505  * @available_down: Available downstream bandwidth (in Mb/s)
1506  *
1507  * Reclaims bandwidth from @available_up and @available_down and updates
1508  * the variables accordingly (e.g decreases both according to what was
1509  * reclaimed by the tunnel). If nothing was reclaimed the values are
1510  * kept as is.
1511  */
1512 void tb_tunnel_reclaim_available_bandwidth(struct tb_tunnel *tunnel,
1513 					   int *available_up,
1514 					   int *available_down)
1515 {
1516 	if (!tb_tunnel_is_active(tunnel))
1517 		return;
1518 
1519 	if (tunnel->reclaim_available_bandwidth)
1520 		tunnel->reclaim_available_bandwidth(tunnel, available_up,
1521 						    available_down);
1522 }
1523