xref: /openbmc/linux/drivers/thunderbolt/tunnel.c (revision e481ff3f)
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 /* Minimum number of credits needed for PCIe path */
38 #define TB_MIN_PCIE_CREDITS		6U
39 /*
40  * Number of credits we try to allocate for each DMA path if not limited
41  * by the host router baMaxHI.
42  */
43 #define TB_DMA_CREDITS			14U
44 /* Minimum number of credits for DMA path */
45 #define TB_MIN_DMA_CREDITS		1U
46 
47 static const char * const tb_tunnel_names[] = { "PCI", "DP", "DMA", "USB3" };
48 
49 #define __TB_TUNNEL_PRINT(level, tunnel, fmt, arg...)                   \
50 	do {                                                            \
51 		struct tb_tunnel *__tunnel = (tunnel);                  \
52 		level(__tunnel->tb, "%llx:%x <-> %llx:%x (%s): " fmt,   \
53 		      tb_route(__tunnel->src_port->sw),                 \
54 		      __tunnel->src_port->port,                         \
55 		      tb_route(__tunnel->dst_port->sw),                 \
56 		      __tunnel->dst_port->port,                         \
57 		      tb_tunnel_names[__tunnel->type],			\
58 		      ## arg);                                          \
59 	} while (0)
60 
61 #define tb_tunnel_WARN(tunnel, fmt, arg...) \
62 	__TB_TUNNEL_PRINT(tb_WARN, tunnel, fmt, ##arg)
63 #define tb_tunnel_warn(tunnel, fmt, arg...) \
64 	__TB_TUNNEL_PRINT(tb_warn, tunnel, fmt, ##arg)
65 #define tb_tunnel_info(tunnel, fmt, arg...) \
66 	__TB_TUNNEL_PRINT(tb_info, tunnel, fmt, ##arg)
67 #define tb_tunnel_dbg(tunnel, fmt, arg...) \
68 	__TB_TUNNEL_PRINT(tb_dbg, tunnel, fmt, ##arg)
69 
70 static inline unsigned int tb_usable_credits(const struct tb_port *port)
71 {
72 	return port->total_credits - port->ctl_credits;
73 }
74 
75 /**
76  * tb_available_credits() - Available credits for PCIe and DMA
77  * @port: Lane adapter to check
78  * @max_dp_streams: If non-%NULL stores maximum number of simultaneous DP
79  *		    streams possible through this lane adapter
80  */
81 static unsigned int tb_available_credits(const struct tb_port *port,
82 					 size_t *max_dp_streams)
83 {
84 	const struct tb_switch *sw = port->sw;
85 	int credits, usb3, pcie, spare;
86 	size_t ndp;
87 
88 	usb3 = tb_acpi_may_tunnel_usb3() ? sw->max_usb3_credits : 0;
89 	pcie = tb_acpi_may_tunnel_pcie() ? sw->max_pcie_credits : 0;
90 
91 	if (tb_acpi_is_xdomain_allowed()) {
92 		spare = min_not_zero(sw->max_dma_credits, TB_DMA_CREDITS);
93 		/* Add some credits for potential second DMA tunnel */
94 		spare += TB_MIN_DMA_CREDITS;
95 	} else {
96 		spare = 0;
97 	}
98 
99 	credits = tb_usable_credits(port);
100 	if (tb_acpi_may_tunnel_dp()) {
101 		/*
102 		 * Maximum number of DP streams possible through the
103 		 * lane adapter.
104 		 */
105 		ndp = (credits - (usb3 + pcie + spare)) /
106 		      (sw->min_dp_aux_credits + sw->min_dp_main_credits);
107 	} else {
108 		ndp = 0;
109 	}
110 	credits -= ndp * (sw->min_dp_aux_credits + sw->min_dp_main_credits);
111 	credits -= usb3;
112 
113 	if (max_dp_streams)
114 		*max_dp_streams = ndp;
115 
116 	return credits > 0 ? credits : 0;
117 }
118 
119 static struct tb_tunnel *tb_tunnel_alloc(struct tb *tb, size_t npaths,
120 					 enum tb_tunnel_type type)
121 {
122 	struct tb_tunnel *tunnel;
123 
124 	tunnel = kzalloc(sizeof(*tunnel), GFP_KERNEL);
125 	if (!tunnel)
126 		return NULL;
127 
128 	tunnel->paths = kcalloc(npaths, sizeof(tunnel->paths[0]), GFP_KERNEL);
129 	if (!tunnel->paths) {
130 		tb_tunnel_free(tunnel);
131 		return NULL;
132 	}
133 
134 	INIT_LIST_HEAD(&tunnel->list);
135 	tunnel->tb = tb;
136 	tunnel->npaths = npaths;
137 	tunnel->type = type;
138 
139 	return tunnel;
140 }
141 
142 static int tb_pci_activate(struct tb_tunnel *tunnel, bool activate)
143 {
144 	int res;
145 
146 	res = tb_pci_port_enable(tunnel->src_port, activate);
147 	if (res)
148 		return res;
149 
150 	if (tb_port_is_pcie_up(tunnel->dst_port))
151 		return tb_pci_port_enable(tunnel->dst_port, activate);
152 
153 	return 0;
154 }
155 
156 static int tb_pci_init_credits(struct tb_path_hop *hop)
157 {
158 	struct tb_port *port = hop->in_port;
159 	struct tb_switch *sw = port->sw;
160 	unsigned int credits;
161 
162 	if (tb_port_use_credit_allocation(port)) {
163 		unsigned int available;
164 
165 		available = tb_available_credits(port, NULL);
166 		credits = min(sw->max_pcie_credits, available);
167 
168 		if (credits < TB_MIN_PCIE_CREDITS)
169 			return -ENOSPC;
170 
171 		credits = max(TB_MIN_PCIE_CREDITS, credits);
172 	} else {
173 		if (tb_port_is_null(port))
174 			credits = port->bonded ? 32 : 16;
175 		else
176 			credits = 7;
177 	}
178 
179 	hop->initial_credits = credits;
180 	return 0;
181 }
182 
183 static int tb_pci_init_path(struct tb_path *path)
184 {
185 	struct tb_path_hop *hop;
186 
187 	path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
188 	path->egress_shared_buffer = TB_PATH_NONE;
189 	path->ingress_fc_enable = TB_PATH_ALL;
190 	path->ingress_shared_buffer = TB_PATH_NONE;
191 	path->priority = 3;
192 	path->weight = 1;
193 	path->drop_packages = 0;
194 
195 	tb_path_for_each_hop(path, hop) {
196 		int ret;
197 
198 		ret = tb_pci_init_credits(hop);
199 		if (ret)
200 			return ret;
201 	}
202 
203 	return 0;
204 }
205 
206 /**
207  * tb_tunnel_discover_pci() - Discover existing PCIe tunnels
208  * @tb: Pointer to the domain structure
209  * @down: PCIe downstream adapter
210  *
211  * If @down adapter is active, follows the tunnel to the PCIe upstream
212  * adapter and back. Returns the discovered tunnel or %NULL if there was
213  * no tunnel.
214  */
215 struct tb_tunnel *tb_tunnel_discover_pci(struct tb *tb, struct tb_port *down)
216 {
217 	struct tb_tunnel *tunnel;
218 	struct tb_path *path;
219 
220 	if (!tb_pci_port_is_enabled(down))
221 		return NULL;
222 
223 	tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_PCI);
224 	if (!tunnel)
225 		return NULL;
226 
227 	tunnel->activate = tb_pci_activate;
228 	tunnel->src_port = down;
229 
230 	/*
231 	 * Discover both paths even if they are not complete. We will
232 	 * clean them up by calling tb_tunnel_deactivate() below in that
233 	 * case.
234 	 */
235 	path = tb_path_discover(down, TB_PCI_HOPID, NULL, -1,
236 				&tunnel->dst_port, "PCIe Up");
237 	if (!path) {
238 		/* Just disable the downstream port */
239 		tb_pci_port_enable(down, false);
240 		goto err_free;
241 	}
242 	tunnel->paths[TB_PCI_PATH_UP] = path;
243 	if (tb_pci_init_path(tunnel->paths[TB_PCI_PATH_UP]))
244 		goto err_free;
245 
246 	path = tb_path_discover(tunnel->dst_port, -1, down, TB_PCI_HOPID, NULL,
247 				"PCIe Down");
248 	if (!path)
249 		goto err_deactivate;
250 	tunnel->paths[TB_PCI_PATH_DOWN] = path;
251 	if (tb_pci_init_path(tunnel->paths[TB_PCI_PATH_DOWN]))
252 		goto err_deactivate;
253 
254 	/* Validate that the tunnel is complete */
255 	if (!tb_port_is_pcie_up(tunnel->dst_port)) {
256 		tb_port_warn(tunnel->dst_port,
257 			     "path does not end on a PCIe adapter, cleaning up\n");
258 		goto err_deactivate;
259 	}
260 
261 	if (down != tunnel->src_port) {
262 		tb_tunnel_warn(tunnel, "path is not complete, cleaning up\n");
263 		goto err_deactivate;
264 	}
265 
266 	if (!tb_pci_port_is_enabled(tunnel->dst_port)) {
267 		tb_tunnel_warn(tunnel,
268 			       "tunnel is not fully activated, cleaning up\n");
269 		goto err_deactivate;
270 	}
271 
272 	tb_tunnel_dbg(tunnel, "discovered\n");
273 	return tunnel;
274 
275 err_deactivate:
276 	tb_tunnel_deactivate(tunnel);
277 err_free:
278 	tb_tunnel_free(tunnel);
279 
280 	return NULL;
281 }
282 
283 /**
284  * tb_tunnel_alloc_pci() - allocate a pci tunnel
285  * @tb: Pointer to the domain structure
286  * @up: PCIe upstream adapter port
287  * @down: PCIe downstream adapter port
288  *
289  * Allocate a PCI tunnel. The ports must be of type TB_TYPE_PCIE_UP and
290  * TB_TYPE_PCIE_DOWN.
291  *
292  * Return: Returns a tb_tunnel on success or NULL on failure.
293  */
294 struct tb_tunnel *tb_tunnel_alloc_pci(struct tb *tb, struct tb_port *up,
295 				      struct tb_port *down)
296 {
297 	struct tb_tunnel *tunnel;
298 	struct tb_path *path;
299 
300 	tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_PCI);
301 	if (!tunnel)
302 		return NULL;
303 
304 	tunnel->activate = tb_pci_activate;
305 	tunnel->src_port = down;
306 	tunnel->dst_port = up;
307 
308 	path = tb_path_alloc(tb, down, TB_PCI_HOPID, up, TB_PCI_HOPID, 0,
309 			     "PCIe Down");
310 	if (!path)
311 		goto err_free;
312 	tunnel->paths[TB_PCI_PATH_DOWN] = path;
313 	if (tb_pci_init_path(path))
314 		goto err_free;
315 
316 	path = tb_path_alloc(tb, up, TB_PCI_HOPID, down, TB_PCI_HOPID, 0,
317 			     "PCIe Up");
318 	if (!path)
319 		goto err_free;
320 	tunnel->paths[TB_PCI_PATH_UP] = path;
321 	if (tb_pci_init_path(path))
322 		goto err_free;
323 
324 	return tunnel;
325 
326 err_free:
327 	tb_tunnel_free(tunnel);
328 	return NULL;
329 }
330 
331 static bool tb_dp_is_usb4(const struct tb_switch *sw)
332 {
333 	/* Titan Ridge DP adapters need the same treatment as USB4 */
334 	return tb_switch_is_usb4(sw) || tb_switch_is_titan_ridge(sw);
335 }
336 
337 static int tb_dp_cm_handshake(struct tb_port *in, struct tb_port *out)
338 {
339 	int timeout = 10;
340 	u32 val;
341 	int ret;
342 
343 	/* Both ends need to support this */
344 	if (!tb_dp_is_usb4(in->sw) || !tb_dp_is_usb4(out->sw))
345 		return 0;
346 
347 	ret = tb_port_read(out, &val, TB_CFG_PORT,
348 			   out->cap_adap + DP_STATUS_CTRL, 1);
349 	if (ret)
350 		return ret;
351 
352 	val |= DP_STATUS_CTRL_UF | DP_STATUS_CTRL_CMHS;
353 
354 	ret = tb_port_write(out, &val, TB_CFG_PORT,
355 			    out->cap_adap + DP_STATUS_CTRL, 1);
356 	if (ret)
357 		return ret;
358 
359 	do {
360 		ret = tb_port_read(out, &val, TB_CFG_PORT,
361 				   out->cap_adap + DP_STATUS_CTRL, 1);
362 		if (ret)
363 			return ret;
364 		if (!(val & DP_STATUS_CTRL_CMHS))
365 			return 0;
366 		usleep_range(10, 100);
367 	} while (timeout--);
368 
369 	return -ETIMEDOUT;
370 }
371 
372 static inline u32 tb_dp_cap_get_rate(u32 val)
373 {
374 	u32 rate = (val & DP_COMMON_CAP_RATE_MASK) >> DP_COMMON_CAP_RATE_SHIFT;
375 
376 	switch (rate) {
377 	case DP_COMMON_CAP_RATE_RBR:
378 		return 1620;
379 	case DP_COMMON_CAP_RATE_HBR:
380 		return 2700;
381 	case DP_COMMON_CAP_RATE_HBR2:
382 		return 5400;
383 	case DP_COMMON_CAP_RATE_HBR3:
384 		return 8100;
385 	default:
386 		return 0;
387 	}
388 }
389 
390 static inline u32 tb_dp_cap_set_rate(u32 val, u32 rate)
391 {
392 	val &= ~DP_COMMON_CAP_RATE_MASK;
393 	switch (rate) {
394 	default:
395 		WARN(1, "invalid rate %u passed, defaulting to 1620 MB/s\n", rate);
396 		fallthrough;
397 	case 1620:
398 		val |= DP_COMMON_CAP_RATE_RBR << DP_COMMON_CAP_RATE_SHIFT;
399 		break;
400 	case 2700:
401 		val |= DP_COMMON_CAP_RATE_HBR << DP_COMMON_CAP_RATE_SHIFT;
402 		break;
403 	case 5400:
404 		val |= DP_COMMON_CAP_RATE_HBR2 << DP_COMMON_CAP_RATE_SHIFT;
405 		break;
406 	case 8100:
407 		val |= DP_COMMON_CAP_RATE_HBR3 << DP_COMMON_CAP_RATE_SHIFT;
408 		break;
409 	}
410 	return val;
411 }
412 
413 static inline u32 tb_dp_cap_get_lanes(u32 val)
414 {
415 	u32 lanes = (val & DP_COMMON_CAP_LANES_MASK) >> DP_COMMON_CAP_LANES_SHIFT;
416 
417 	switch (lanes) {
418 	case DP_COMMON_CAP_1_LANE:
419 		return 1;
420 	case DP_COMMON_CAP_2_LANES:
421 		return 2;
422 	case DP_COMMON_CAP_4_LANES:
423 		return 4;
424 	default:
425 		return 0;
426 	}
427 }
428 
429 static inline u32 tb_dp_cap_set_lanes(u32 val, u32 lanes)
430 {
431 	val &= ~DP_COMMON_CAP_LANES_MASK;
432 	switch (lanes) {
433 	default:
434 		WARN(1, "invalid number of lanes %u passed, defaulting to 1\n",
435 		     lanes);
436 		fallthrough;
437 	case 1:
438 		val |= DP_COMMON_CAP_1_LANE << DP_COMMON_CAP_LANES_SHIFT;
439 		break;
440 	case 2:
441 		val |= DP_COMMON_CAP_2_LANES << DP_COMMON_CAP_LANES_SHIFT;
442 		break;
443 	case 4:
444 		val |= DP_COMMON_CAP_4_LANES << DP_COMMON_CAP_LANES_SHIFT;
445 		break;
446 	}
447 	return val;
448 }
449 
450 static unsigned int tb_dp_bandwidth(unsigned int rate, unsigned int lanes)
451 {
452 	/* Tunneling removes the DP 8b/10b encoding */
453 	return rate * lanes * 8 / 10;
454 }
455 
456 static int tb_dp_reduce_bandwidth(int max_bw, u32 in_rate, u32 in_lanes,
457 				  u32 out_rate, u32 out_lanes, u32 *new_rate,
458 				  u32 *new_lanes)
459 {
460 	static const u32 dp_bw[][2] = {
461 		/* Mb/s, lanes */
462 		{ 8100, 4 }, /* 25920 Mb/s */
463 		{ 5400, 4 }, /* 17280 Mb/s */
464 		{ 8100, 2 }, /* 12960 Mb/s */
465 		{ 2700, 4 }, /* 8640 Mb/s */
466 		{ 5400, 2 }, /* 8640 Mb/s */
467 		{ 8100, 1 }, /* 6480 Mb/s */
468 		{ 1620, 4 }, /* 5184 Mb/s */
469 		{ 5400, 1 }, /* 4320 Mb/s */
470 		{ 2700, 2 }, /* 4320 Mb/s */
471 		{ 1620, 2 }, /* 2592 Mb/s */
472 		{ 2700, 1 }, /* 2160 Mb/s */
473 		{ 1620, 1 }, /* 1296 Mb/s */
474 	};
475 	unsigned int i;
476 
477 	/*
478 	 * Find a combination that can fit into max_bw and does not
479 	 * exceed the maximum rate and lanes supported by the DP OUT and
480 	 * DP IN adapters.
481 	 */
482 	for (i = 0; i < ARRAY_SIZE(dp_bw); i++) {
483 		if (dp_bw[i][0] > out_rate || dp_bw[i][1] > out_lanes)
484 			continue;
485 
486 		if (dp_bw[i][0] > in_rate || dp_bw[i][1] > in_lanes)
487 			continue;
488 
489 		if (tb_dp_bandwidth(dp_bw[i][0], dp_bw[i][1]) <= max_bw) {
490 			*new_rate = dp_bw[i][0];
491 			*new_lanes = dp_bw[i][1];
492 			return 0;
493 		}
494 	}
495 
496 	return -ENOSR;
497 }
498 
499 static int tb_dp_xchg_caps(struct tb_tunnel *tunnel)
500 {
501 	u32 out_dp_cap, out_rate, out_lanes, in_dp_cap, in_rate, in_lanes, bw;
502 	struct tb_port *out = tunnel->dst_port;
503 	struct tb_port *in = tunnel->src_port;
504 	int ret, max_bw;
505 
506 	/*
507 	 * Copy DP_LOCAL_CAP register to DP_REMOTE_CAP register for
508 	 * newer generation hardware.
509 	 */
510 	if (in->sw->generation < 2 || out->sw->generation < 2)
511 		return 0;
512 
513 	/*
514 	 * Perform connection manager handshake between IN and OUT ports
515 	 * before capabilities exchange can take place.
516 	 */
517 	ret = tb_dp_cm_handshake(in, out);
518 	if (ret)
519 		return ret;
520 
521 	/* Read both DP_LOCAL_CAP registers */
522 	ret = tb_port_read(in, &in_dp_cap, TB_CFG_PORT,
523 			   in->cap_adap + DP_LOCAL_CAP, 1);
524 	if (ret)
525 		return ret;
526 
527 	ret = tb_port_read(out, &out_dp_cap, TB_CFG_PORT,
528 			   out->cap_adap + DP_LOCAL_CAP, 1);
529 	if (ret)
530 		return ret;
531 
532 	/* Write IN local caps to OUT remote caps */
533 	ret = tb_port_write(out, &in_dp_cap, TB_CFG_PORT,
534 			    out->cap_adap + DP_REMOTE_CAP, 1);
535 	if (ret)
536 		return ret;
537 
538 	in_rate = tb_dp_cap_get_rate(in_dp_cap);
539 	in_lanes = tb_dp_cap_get_lanes(in_dp_cap);
540 	tb_port_dbg(in, "maximum supported bandwidth %u Mb/s x%u = %u Mb/s\n",
541 		    in_rate, in_lanes, tb_dp_bandwidth(in_rate, in_lanes));
542 
543 	/*
544 	 * If the tunnel bandwidth is limited (max_bw is set) then see
545 	 * if we need to reduce bandwidth to fit there.
546 	 */
547 	out_rate = tb_dp_cap_get_rate(out_dp_cap);
548 	out_lanes = tb_dp_cap_get_lanes(out_dp_cap);
549 	bw = tb_dp_bandwidth(out_rate, out_lanes);
550 	tb_port_dbg(out, "maximum supported bandwidth %u Mb/s x%u = %u Mb/s\n",
551 		    out_rate, out_lanes, bw);
552 
553 	if (in->sw->config.depth < out->sw->config.depth)
554 		max_bw = tunnel->max_down;
555 	else
556 		max_bw = tunnel->max_up;
557 
558 	if (max_bw && bw > max_bw) {
559 		u32 new_rate, new_lanes, new_bw;
560 
561 		ret = tb_dp_reduce_bandwidth(max_bw, in_rate, in_lanes,
562 					     out_rate, out_lanes, &new_rate,
563 					     &new_lanes);
564 		if (ret) {
565 			tb_port_info(out, "not enough bandwidth for DP tunnel\n");
566 			return ret;
567 		}
568 
569 		new_bw = tb_dp_bandwidth(new_rate, new_lanes);
570 		tb_port_dbg(out, "bandwidth reduced to %u Mb/s x%u = %u Mb/s\n",
571 			    new_rate, new_lanes, new_bw);
572 
573 		/*
574 		 * Set new rate and number of lanes before writing it to
575 		 * the IN port remote caps.
576 		 */
577 		out_dp_cap = tb_dp_cap_set_rate(out_dp_cap, new_rate);
578 		out_dp_cap = tb_dp_cap_set_lanes(out_dp_cap, new_lanes);
579 	}
580 
581 	return tb_port_write(in, &out_dp_cap, TB_CFG_PORT,
582 			     in->cap_adap + DP_REMOTE_CAP, 1);
583 }
584 
585 static int tb_dp_activate(struct tb_tunnel *tunnel, bool active)
586 {
587 	int ret;
588 
589 	if (active) {
590 		struct tb_path **paths;
591 		int last;
592 
593 		paths = tunnel->paths;
594 		last = paths[TB_DP_VIDEO_PATH_OUT]->path_length - 1;
595 
596 		tb_dp_port_set_hops(tunnel->src_port,
597 			paths[TB_DP_VIDEO_PATH_OUT]->hops[0].in_hop_index,
598 			paths[TB_DP_AUX_PATH_OUT]->hops[0].in_hop_index,
599 			paths[TB_DP_AUX_PATH_IN]->hops[last].next_hop_index);
600 
601 		tb_dp_port_set_hops(tunnel->dst_port,
602 			paths[TB_DP_VIDEO_PATH_OUT]->hops[last].next_hop_index,
603 			paths[TB_DP_AUX_PATH_IN]->hops[0].in_hop_index,
604 			paths[TB_DP_AUX_PATH_OUT]->hops[last].next_hop_index);
605 	} else {
606 		tb_dp_port_hpd_clear(tunnel->src_port);
607 		tb_dp_port_set_hops(tunnel->src_port, 0, 0, 0);
608 		if (tb_port_is_dpout(tunnel->dst_port))
609 			tb_dp_port_set_hops(tunnel->dst_port, 0, 0, 0);
610 	}
611 
612 	ret = tb_dp_port_enable(tunnel->src_port, active);
613 	if (ret)
614 		return ret;
615 
616 	if (tb_port_is_dpout(tunnel->dst_port))
617 		return tb_dp_port_enable(tunnel->dst_port, active);
618 
619 	return 0;
620 }
621 
622 static int tb_dp_consumed_bandwidth(struct tb_tunnel *tunnel, int *consumed_up,
623 				    int *consumed_down)
624 {
625 	struct tb_port *in = tunnel->src_port;
626 	const struct tb_switch *sw = in->sw;
627 	u32 val, rate = 0, lanes = 0;
628 	int ret;
629 
630 	if (tb_dp_is_usb4(sw)) {
631 		int timeout = 20;
632 
633 		/*
634 		 * Wait for DPRX done. Normally it should be already set
635 		 * for active tunnel.
636 		 */
637 		do {
638 			ret = tb_port_read(in, &val, TB_CFG_PORT,
639 					   in->cap_adap + DP_COMMON_CAP, 1);
640 			if (ret)
641 				return ret;
642 
643 			if (val & DP_COMMON_CAP_DPRX_DONE) {
644 				rate = tb_dp_cap_get_rate(val);
645 				lanes = tb_dp_cap_get_lanes(val);
646 				break;
647 			}
648 			msleep(250);
649 		} while (timeout--);
650 
651 		if (!timeout)
652 			return -ETIMEDOUT;
653 	} else if (sw->generation >= 2) {
654 		/*
655 		 * Read from the copied remote cap so that we take into
656 		 * account if capabilities were reduced during exchange.
657 		 */
658 		ret = tb_port_read(in, &val, TB_CFG_PORT,
659 				   in->cap_adap + DP_REMOTE_CAP, 1);
660 		if (ret)
661 			return ret;
662 
663 		rate = tb_dp_cap_get_rate(val);
664 		lanes = tb_dp_cap_get_lanes(val);
665 	} else {
666 		/* No bandwidth management for legacy devices  */
667 		*consumed_up = 0;
668 		*consumed_down = 0;
669 		return 0;
670 	}
671 
672 	if (in->sw->config.depth < tunnel->dst_port->sw->config.depth) {
673 		*consumed_up = 0;
674 		*consumed_down = tb_dp_bandwidth(rate, lanes);
675 	} else {
676 		*consumed_up = tb_dp_bandwidth(rate, lanes);
677 		*consumed_down = 0;
678 	}
679 
680 	return 0;
681 }
682 
683 static void tb_dp_init_aux_credits(struct tb_path_hop *hop)
684 {
685 	struct tb_port *port = hop->in_port;
686 	struct tb_switch *sw = port->sw;
687 
688 	if (tb_port_use_credit_allocation(port))
689 		hop->initial_credits = sw->min_dp_aux_credits;
690 	else
691 		hop->initial_credits = 1;
692 }
693 
694 static void tb_dp_init_aux_path(struct tb_path *path)
695 {
696 	struct tb_path_hop *hop;
697 
698 	path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
699 	path->egress_shared_buffer = TB_PATH_NONE;
700 	path->ingress_fc_enable = TB_PATH_ALL;
701 	path->ingress_shared_buffer = TB_PATH_NONE;
702 	path->priority = 2;
703 	path->weight = 1;
704 
705 	tb_path_for_each_hop(path, hop)
706 		tb_dp_init_aux_credits(hop);
707 }
708 
709 static int tb_dp_init_video_credits(struct tb_path_hop *hop)
710 {
711 	struct tb_port *port = hop->in_port;
712 	struct tb_switch *sw = port->sw;
713 
714 	if (tb_port_use_credit_allocation(port)) {
715 		unsigned int nfc_credits;
716 		size_t max_dp_streams;
717 
718 		tb_available_credits(port, &max_dp_streams);
719 		/*
720 		 * Read the number of currently allocated NFC credits
721 		 * from the lane adapter. Since we only use them for DP
722 		 * tunneling we can use that to figure out how many DP
723 		 * tunnels already go through the lane adapter.
724 		 */
725 		nfc_credits = port->config.nfc_credits &
726 				ADP_CS_4_NFC_BUFFERS_MASK;
727 		if (nfc_credits / sw->min_dp_main_credits > max_dp_streams)
728 			return -ENOSPC;
729 
730 		hop->nfc_credits = sw->min_dp_main_credits;
731 	} else {
732 		hop->nfc_credits = min(port->total_credits - 2, 12U);
733 	}
734 
735 	return 0;
736 }
737 
738 static int tb_dp_init_video_path(struct tb_path *path)
739 {
740 	struct tb_path_hop *hop;
741 
742 	path->egress_fc_enable = TB_PATH_NONE;
743 	path->egress_shared_buffer = TB_PATH_NONE;
744 	path->ingress_fc_enable = TB_PATH_NONE;
745 	path->ingress_shared_buffer = TB_PATH_NONE;
746 	path->priority = 1;
747 	path->weight = 1;
748 
749 	tb_path_for_each_hop(path, hop) {
750 		int ret;
751 
752 		ret = tb_dp_init_video_credits(hop);
753 		if (ret)
754 			return ret;
755 	}
756 
757 	return 0;
758 }
759 
760 /**
761  * tb_tunnel_discover_dp() - Discover existing Display Port tunnels
762  * @tb: Pointer to the domain structure
763  * @in: DP in adapter
764  *
765  * If @in adapter is active, follows the tunnel to the DP out adapter
766  * and back. Returns the discovered tunnel or %NULL if there was no
767  * tunnel.
768  *
769  * Return: DP tunnel or %NULL if no tunnel found.
770  */
771 struct tb_tunnel *tb_tunnel_discover_dp(struct tb *tb, struct tb_port *in)
772 {
773 	struct tb_tunnel *tunnel;
774 	struct tb_port *port;
775 	struct tb_path *path;
776 
777 	if (!tb_dp_port_is_enabled(in))
778 		return NULL;
779 
780 	tunnel = tb_tunnel_alloc(tb, 3, TB_TUNNEL_DP);
781 	if (!tunnel)
782 		return NULL;
783 
784 	tunnel->init = tb_dp_xchg_caps;
785 	tunnel->activate = tb_dp_activate;
786 	tunnel->consumed_bandwidth = tb_dp_consumed_bandwidth;
787 	tunnel->src_port = in;
788 
789 	path = tb_path_discover(in, TB_DP_VIDEO_HOPID, NULL, -1,
790 				&tunnel->dst_port, "Video");
791 	if (!path) {
792 		/* Just disable the DP IN port */
793 		tb_dp_port_enable(in, false);
794 		goto err_free;
795 	}
796 	tunnel->paths[TB_DP_VIDEO_PATH_OUT] = path;
797 	if (tb_dp_init_video_path(tunnel->paths[TB_DP_VIDEO_PATH_OUT]))
798 		goto err_free;
799 
800 	path = tb_path_discover(in, TB_DP_AUX_TX_HOPID, NULL, -1, NULL, "AUX TX");
801 	if (!path)
802 		goto err_deactivate;
803 	tunnel->paths[TB_DP_AUX_PATH_OUT] = path;
804 	tb_dp_init_aux_path(tunnel->paths[TB_DP_AUX_PATH_OUT]);
805 
806 	path = tb_path_discover(tunnel->dst_port, -1, in, TB_DP_AUX_RX_HOPID,
807 				&port, "AUX RX");
808 	if (!path)
809 		goto err_deactivate;
810 	tunnel->paths[TB_DP_AUX_PATH_IN] = path;
811 	tb_dp_init_aux_path(tunnel->paths[TB_DP_AUX_PATH_IN]);
812 
813 	/* Validate that the tunnel is complete */
814 	if (!tb_port_is_dpout(tunnel->dst_port)) {
815 		tb_port_warn(in, "path does not end on a DP adapter, cleaning up\n");
816 		goto err_deactivate;
817 	}
818 
819 	if (!tb_dp_port_is_enabled(tunnel->dst_port))
820 		goto err_deactivate;
821 
822 	if (!tb_dp_port_hpd_is_active(tunnel->dst_port))
823 		goto err_deactivate;
824 
825 	if (port != tunnel->src_port) {
826 		tb_tunnel_warn(tunnel, "path is not complete, cleaning up\n");
827 		goto err_deactivate;
828 	}
829 
830 	tb_tunnel_dbg(tunnel, "discovered\n");
831 	return tunnel;
832 
833 err_deactivate:
834 	tb_tunnel_deactivate(tunnel);
835 err_free:
836 	tb_tunnel_free(tunnel);
837 
838 	return NULL;
839 }
840 
841 /**
842  * tb_tunnel_alloc_dp() - allocate a Display Port tunnel
843  * @tb: Pointer to the domain structure
844  * @in: DP in adapter port
845  * @out: DP out adapter port
846  * @max_up: Maximum available upstream bandwidth for the DP tunnel (%0
847  *	    if not limited)
848  * @max_down: Maximum available downstream bandwidth for the DP tunnel
849  *	      (%0 if not limited)
850  *
851  * Allocates a tunnel between @in and @out that is capable of tunneling
852  * Display Port traffic.
853  *
854  * Return: Returns a tb_tunnel on success or NULL on failure.
855  */
856 struct tb_tunnel *tb_tunnel_alloc_dp(struct tb *tb, struct tb_port *in,
857 				     struct tb_port *out, int max_up,
858 				     int max_down)
859 {
860 	struct tb_tunnel *tunnel;
861 	struct tb_path **paths;
862 	struct tb_path *path;
863 
864 	if (WARN_ON(!in->cap_adap || !out->cap_adap))
865 		return NULL;
866 
867 	tunnel = tb_tunnel_alloc(tb, 3, TB_TUNNEL_DP);
868 	if (!tunnel)
869 		return NULL;
870 
871 	tunnel->init = tb_dp_xchg_caps;
872 	tunnel->activate = tb_dp_activate;
873 	tunnel->consumed_bandwidth = tb_dp_consumed_bandwidth;
874 	tunnel->src_port = in;
875 	tunnel->dst_port = out;
876 	tunnel->max_up = max_up;
877 	tunnel->max_down = max_down;
878 
879 	paths = tunnel->paths;
880 
881 	path = tb_path_alloc(tb, in, TB_DP_VIDEO_HOPID, out, TB_DP_VIDEO_HOPID,
882 			     1, "Video");
883 	if (!path)
884 		goto err_free;
885 	tb_dp_init_video_path(path);
886 	paths[TB_DP_VIDEO_PATH_OUT] = path;
887 
888 	path = tb_path_alloc(tb, in, TB_DP_AUX_TX_HOPID, out,
889 			     TB_DP_AUX_TX_HOPID, 1, "AUX TX");
890 	if (!path)
891 		goto err_free;
892 	tb_dp_init_aux_path(path);
893 	paths[TB_DP_AUX_PATH_OUT] = path;
894 
895 	path = tb_path_alloc(tb, out, TB_DP_AUX_RX_HOPID, in,
896 			     TB_DP_AUX_RX_HOPID, 1, "AUX RX");
897 	if (!path)
898 		goto err_free;
899 	tb_dp_init_aux_path(path);
900 	paths[TB_DP_AUX_PATH_IN] = path;
901 
902 	return tunnel;
903 
904 err_free:
905 	tb_tunnel_free(tunnel);
906 	return NULL;
907 }
908 
909 static unsigned int tb_dma_available_credits(const struct tb_port *port)
910 {
911 	const struct tb_switch *sw = port->sw;
912 	int credits;
913 
914 	credits = tb_available_credits(port, NULL);
915 	if (tb_acpi_may_tunnel_pcie())
916 		credits -= sw->max_pcie_credits;
917 	credits -= port->dma_credits;
918 
919 	return credits > 0 ? credits : 0;
920 }
921 
922 static int tb_dma_reserve_credits(struct tb_path_hop *hop, unsigned int credits)
923 {
924 	struct tb_port *port = hop->in_port;
925 
926 	if (tb_port_use_credit_allocation(port)) {
927 		unsigned int available = tb_dma_available_credits(port);
928 
929 		/*
930 		 * Need to have at least TB_MIN_DMA_CREDITS, otherwise
931 		 * DMA path cannot be established.
932 		 */
933 		if (available < TB_MIN_DMA_CREDITS)
934 			return -ENOSPC;
935 
936 		while (credits > available)
937 			credits--;
938 
939 		tb_port_dbg(port, "reserving %u credits for DMA path\n",
940 			    credits);
941 
942 		port->dma_credits += credits;
943 	} else {
944 		if (tb_port_is_null(port))
945 			credits = port->bonded ? 14 : 6;
946 		else
947 			credits = min(port->total_credits, credits);
948 	}
949 
950 	hop->initial_credits = credits;
951 	return 0;
952 }
953 
954 /* Path from lane adapter to NHI */
955 static int tb_dma_init_rx_path(struct tb_path *path, unsigned int credits)
956 {
957 	struct tb_path_hop *hop;
958 	unsigned int i, tmp;
959 
960 	path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
961 	path->ingress_fc_enable = TB_PATH_ALL;
962 	path->egress_shared_buffer = TB_PATH_NONE;
963 	path->ingress_shared_buffer = TB_PATH_NONE;
964 	path->priority = 5;
965 	path->weight = 1;
966 	path->clear_fc = true;
967 
968 	/*
969 	 * First lane adapter is the one connected to the remote host.
970 	 * We don't tunnel other traffic over this link so can use all
971 	 * the credits (except the ones reserved for control traffic).
972 	 */
973 	hop = &path->hops[0];
974 	tmp = min(tb_usable_credits(hop->in_port), credits);
975 	hop->initial_credits = tmp;
976 	hop->in_port->dma_credits += tmp;
977 
978 	for (i = 1; i < path->path_length; i++) {
979 		int ret;
980 
981 		ret = tb_dma_reserve_credits(&path->hops[i], credits);
982 		if (ret)
983 			return ret;
984 	}
985 
986 	return 0;
987 }
988 
989 /* Path from NHI to lane adapter */
990 static int tb_dma_init_tx_path(struct tb_path *path, unsigned int credits)
991 {
992 	struct tb_path_hop *hop;
993 
994 	path->egress_fc_enable = TB_PATH_ALL;
995 	path->ingress_fc_enable = TB_PATH_ALL;
996 	path->egress_shared_buffer = TB_PATH_NONE;
997 	path->ingress_shared_buffer = TB_PATH_NONE;
998 	path->priority = 5;
999 	path->weight = 1;
1000 	path->clear_fc = true;
1001 
1002 	tb_path_for_each_hop(path, hop) {
1003 		int ret;
1004 
1005 		ret = tb_dma_reserve_credits(hop, credits);
1006 		if (ret)
1007 			return ret;
1008 	}
1009 
1010 	return 0;
1011 }
1012 
1013 static void tb_dma_release_credits(struct tb_path_hop *hop)
1014 {
1015 	struct tb_port *port = hop->in_port;
1016 
1017 	if (tb_port_use_credit_allocation(port)) {
1018 		port->dma_credits -= hop->initial_credits;
1019 
1020 		tb_port_dbg(port, "released %u DMA path credits\n",
1021 			    hop->initial_credits);
1022 	}
1023 }
1024 
1025 static void tb_dma_deinit_path(struct tb_path *path)
1026 {
1027 	struct tb_path_hop *hop;
1028 
1029 	tb_path_for_each_hop(path, hop)
1030 		tb_dma_release_credits(hop);
1031 }
1032 
1033 static void tb_dma_deinit(struct tb_tunnel *tunnel)
1034 {
1035 	int i;
1036 
1037 	for (i = 0; i < tunnel->npaths; i++) {
1038 		if (!tunnel->paths[i])
1039 			continue;
1040 		tb_dma_deinit_path(tunnel->paths[i]);
1041 	}
1042 }
1043 
1044 /**
1045  * tb_tunnel_alloc_dma() - allocate a DMA tunnel
1046  * @tb: Pointer to the domain structure
1047  * @nhi: Host controller port
1048  * @dst: Destination null port which the other domain is connected to
1049  * @transmit_path: HopID used for transmitting packets
1050  * @transmit_ring: NHI ring number used to send packets towards the
1051  *		   other domain. Set to %-1 if TX path is not needed.
1052  * @receive_path: HopID used for receiving packets
1053  * @receive_ring: NHI ring number used to receive packets from the
1054  *		  other domain. Set to %-1 if RX path is not needed.
1055  *
1056  * Return: Returns a tb_tunnel on success or NULL on failure.
1057  */
1058 struct tb_tunnel *tb_tunnel_alloc_dma(struct tb *tb, struct tb_port *nhi,
1059 				      struct tb_port *dst, int transmit_path,
1060 				      int transmit_ring, int receive_path,
1061 				      int receive_ring)
1062 {
1063 	struct tb_tunnel *tunnel;
1064 	size_t npaths = 0, i = 0;
1065 	struct tb_path *path;
1066 	int credits;
1067 
1068 	if (receive_ring > 0)
1069 		npaths++;
1070 	if (transmit_ring > 0)
1071 		npaths++;
1072 
1073 	if (WARN_ON(!npaths))
1074 		return NULL;
1075 
1076 	tunnel = tb_tunnel_alloc(tb, npaths, TB_TUNNEL_DMA);
1077 	if (!tunnel)
1078 		return NULL;
1079 
1080 	tunnel->src_port = nhi;
1081 	tunnel->dst_port = dst;
1082 	tunnel->deinit = tb_dma_deinit;
1083 
1084 	credits = min_not_zero(TB_DMA_CREDITS, nhi->sw->max_dma_credits);
1085 
1086 	if (receive_ring > 0) {
1087 		path = tb_path_alloc(tb, dst, receive_path, nhi, receive_ring, 0,
1088 				     "DMA RX");
1089 		if (!path)
1090 			goto err_free;
1091 		tunnel->paths[i++] = path;
1092 		if (tb_dma_init_rx_path(path, credits)) {
1093 			tb_tunnel_dbg(tunnel, "not enough buffers for RX path\n");
1094 			goto err_free;
1095 		}
1096 	}
1097 
1098 	if (transmit_ring > 0) {
1099 		path = tb_path_alloc(tb, nhi, transmit_ring, dst, transmit_path, 0,
1100 				     "DMA TX");
1101 		if (!path)
1102 			goto err_free;
1103 		tunnel->paths[i++] = path;
1104 		if (tb_dma_init_tx_path(path, credits)) {
1105 			tb_tunnel_dbg(tunnel, "not enough buffers for TX path\n");
1106 			goto err_free;
1107 		}
1108 	}
1109 
1110 	return tunnel;
1111 
1112 err_free:
1113 	tb_tunnel_free(tunnel);
1114 	return NULL;
1115 }
1116 
1117 /**
1118  * tb_tunnel_match_dma() - Match DMA tunnel
1119  * @tunnel: Tunnel to match
1120  * @transmit_path: HopID used for transmitting packets. Pass %-1 to ignore.
1121  * @transmit_ring: NHI ring number used to send packets towards the
1122  *		   other domain. Pass %-1 to ignore.
1123  * @receive_path: HopID used for receiving packets. Pass %-1 to ignore.
1124  * @receive_ring: NHI ring number used to receive packets from the
1125  *		  other domain. Pass %-1 to ignore.
1126  *
1127  * This function can be used to match specific DMA tunnel, if there are
1128  * multiple DMA tunnels going through the same XDomain connection.
1129  * Returns true if there is match and false otherwise.
1130  */
1131 bool tb_tunnel_match_dma(const struct tb_tunnel *tunnel, int transmit_path,
1132 			 int transmit_ring, int receive_path, int receive_ring)
1133 {
1134 	const struct tb_path *tx_path = NULL, *rx_path = NULL;
1135 	int i;
1136 
1137 	if (!receive_ring || !transmit_ring)
1138 		return false;
1139 
1140 	for (i = 0; i < tunnel->npaths; i++) {
1141 		const struct tb_path *path = tunnel->paths[i];
1142 
1143 		if (!path)
1144 			continue;
1145 
1146 		if (tb_port_is_nhi(path->hops[0].in_port))
1147 			tx_path = path;
1148 		else if (tb_port_is_nhi(path->hops[path->path_length - 1].out_port))
1149 			rx_path = path;
1150 	}
1151 
1152 	if (transmit_ring > 0 || transmit_path > 0) {
1153 		if (!tx_path)
1154 			return false;
1155 		if (transmit_ring > 0 &&
1156 		    (tx_path->hops[0].in_hop_index != transmit_ring))
1157 			return false;
1158 		if (transmit_path > 0 &&
1159 		    (tx_path->hops[tx_path->path_length - 1].next_hop_index != transmit_path))
1160 			return false;
1161 	}
1162 
1163 	if (receive_ring > 0 || receive_path > 0) {
1164 		if (!rx_path)
1165 			return false;
1166 		if (receive_path > 0 &&
1167 		    (rx_path->hops[0].in_hop_index != receive_path))
1168 			return false;
1169 		if (receive_ring > 0 &&
1170 		    (rx_path->hops[rx_path->path_length - 1].next_hop_index != receive_ring))
1171 			return false;
1172 	}
1173 
1174 	return true;
1175 }
1176 
1177 static int tb_usb3_max_link_rate(struct tb_port *up, struct tb_port *down)
1178 {
1179 	int ret, up_max_rate, down_max_rate;
1180 
1181 	ret = usb4_usb3_port_max_link_rate(up);
1182 	if (ret < 0)
1183 		return ret;
1184 	up_max_rate = ret;
1185 
1186 	ret = usb4_usb3_port_max_link_rate(down);
1187 	if (ret < 0)
1188 		return ret;
1189 	down_max_rate = ret;
1190 
1191 	return min(up_max_rate, down_max_rate);
1192 }
1193 
1194 static int tb_usb3_init(struct tb_tunnel *tunnel)
1195 {
1196 	tb_tunnel_dbg(tunnel, "allocating initial bandwidth %d/%d Mb/s\n",
1197 		      tunnel->allocated_up, tunnel->allocated_down);
1198 
1199 	return usb4_usb3_port_allocate_bandwidth(tunnel->src_port,
1200 						 &tunnel->allocated_up,
1201 						 &tunnel->allocated_down);
1202 }
1203 
1204 static int tb_usb3_activate(struct tb_tunnel *tunnel, bool activate)
1205 {
1206 	int res;
1207 
1208 	res = tb_usb3_port_enable(tunnel->src_port, activate);
1209 	if (res)
1210 		return res;
1211 
1212 	if (tb_port_is_usb3_up(tunnel->dst_port))
1213 		return tb_usb3_port_enable(tunnel->dst_port, activate);
1214 
1215 	return 0;
1216 }
1217 
1218 static int tb_usb3_consumed_bandwidth(struct tb_tunnel *tunnel,
1219 		int *consumed_up, int *consumed_down)
1220 {
1221 	int pcie_enabled = tb_acpi_may_tunnel_pcie();
1222 
1223 	/*
1224 	 * PCIe tunneling, if enabled, affects the USB3 bandwidth so
1225 	 * take that it into account here.
1226 	 */
1227 	*consumed_up = tunnel->allocated_up * (3 + pcie_enabled) / 3;
1228 	*consumed_down = tunnel->allocated_down * (3 + pcie_enabled) / 3;
1229 	return 0;
1230 }
1231 
1232 static int tb_usb3_release_unused_bandwidth(struct tb_tunnel *tunnel)
1233 {
1234 	int ret;
1235 
1236 	ret = usb4_usb3_port_release_bandwidth(tunnel->src_port,
1237 					       &tunnel->allocated_up,
1238 					       &tunnel->allocated_down);
1239 	if (ret)
1240 		return ret;
1241 
1242 	tb_tunnel_dbg(tunnel, "decreased bandwidth allocation to %d/%d Mb/s\n",
1243 		      tunnel->allocated_up, tunnel->allocated_down);
1244 	return 0;
1245 }
1246 
1247 static void tb_usb3_reclaim_available_bandwidth(struct tb_tunnel *tunnel,
1248 						int *available_up,
1249 						int *available_down)
1250 {
1251 	int ret, max_rate, allocate_up, allocate_down;
1252 
1253 	ret = usb4_usb3_port_actual_link_rate(tunnel->src_port);
1254 	if (ret < 0) {
1255 		tb_tunnel_warn(tunnel, "failed to read actual link rate\n");
1256 		return;
1257 	} else if (!ret) {
1258 		/* Use maximum link rate if the link valid is not set */
1259 		ret = usb4_usb3_port_max_link_rate(tunnel->src_port);
1260 		if (ret < 0) {
1261 			tb_tunnel_warn(tunnel, "failed to read maximum link rate\n");
1262 			return;
1263 		}
1264 	}
1265 
1266 	/*
1267 	 * 90% of the max rate can be allocated for isochronous
1268 	 * transfers.
1269 	 */
1270 	max_rate = ret * 90 / 100;
1271 
1272 	/* No need to reclaim if already at maximum */
1273 	if (tunnel->allocated_up >= max_rate &&
1274 	    tunnel->allocated_down >= max_rate)
1275 		return;
1276 
1277 	/* Don't go lower than what is already allocated */
1278 	allocate_up = min(max_rate, *available_up);
1279 	if (allocate_up < tunnel->allocated_up)
1280 		allocate_up = tunnel->allocated_up;
1281 
1282 	allocate_down = min(max_rate, *available_down);
1283 	if (allocate_down < tunnel->allocated_down)
1284 		allocate_down = tunnel->allocated_down;
1285 
1286 	/* If no changes no need to do more */
1287 	if (allocate_up == tunnel->allocated_up &&
1288 	    allocate_down == tunnel->allocated_down)
1289 		return;
1290 
1291 	ret = usb4_usb3_port_allocate_bandwidth(tunnel->src_port, &allocate_up,
1292 						&allocate_down);
1293 	if (ret) {
1294 		tb_tunnel_info(tunnel, "failed to allocate bandwidth\n");
1295 		return;
1296 	}
1297 
1298 	tunnel->allocated_up = allocate_up;
1299 	*available_up -= tunnel->allocated_up;
1300 
1301 	tunnel->allocated_down = allocate_down;
1302 	*available_down -= tunnel->allocated_down;
1303 
1304 	tb_tunnel_dbg(tunnel, "increased bandwidth allocation to %d/%d Mb/s\n",
1305 		      tunnel->allocated_up, tunnel->allocated_down);
1306 }
1307 
1308 static void tb_usb3_init_credits(struct tb_path_hop *hop)
1309 {
1310 	struct tb_port *port = hop->in_port;
1311 	struct tb_switch *sw = port->sw;
1312 	unsigned int credits;
1313 
1314 	if (tb_port_use_credit_allocation(port)) {
1315 		credits = sw->max_usb3_credits;
1316 	} else {
1317 		if (tb_port_is_null(port))
1318 			credits = port->bonded ? 32 : 16;
1319 		else
1320 			credits = 7;
1321 	}
1322 
1323 	hop->initial_credits = credits;
1324 }
1325 
1326 static void tb_usb3_init_path(struct tb_path *path)
1327 {
1328 	struct tb_path_hop *hop;
1329 
1330 	path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
1331 	path->egress_shared_buffer = TB_PATH_NONE;
1332 	path->ingress_fc_enable = TB_PATH_ALL;
1333 	path->ingress_shared_buffer = TB_PATH_NONE;
1334 	path->priority = 3;
1335 	path->weight = 3;
1336 	path->drop_packages = 0;
1337 
1338 	tb_path_for_each_hop(path, hop)
1339 		tb_usb3_init_credits(hop);
1340 }
1341 
1342 /**
1343  * tb_tunnel_discover_usb3() - Discover existing USB3 tunnels
1344  * @tb: Pointer to the domain structure
1345  * @down: USB3 downstream adapter
1346  *
1347  * If @down adapter is active, follows the tunnel to the USB3 upstream
1348  * adapter and back. Returns the discovered tunnel or %NULL if there was
1349  * no tunnel.
1350  */
1351 struct tb_tunnel *tb_tunnel_discover_usb3(struct tb *tb, struct tb_port *down)
1352 {
1353 	struct tb_tunnel *tunnel;
1354 	struct tb_path *path;
1355 
1356 	if (!tb_usb3_port_is_enabled(down))
1357 		return NULL;
1358 
1359 	tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_USB3);
1360 	if (!tunnel)
1361 		return NULL;
1362 
1363 	tunnel->activate = tb_usb3_activate;
1364 	tunnel->src_port = down;
1365 
1366 	/*
1367 	 * Discover both paths even if they are not complete. We will
1368 	 * clean them up by calling tb_tunnel_deactivate() below in that
1369 	 * case.
1370 	 */
1371 	path = tb_path_discover(down, TB_USB3_HOPID, NULL, -1,
1372 				&tunnel->dst_port, "USB3 Down");
1373 	if (!path) {
1374 		/* Just disable the downstream port */
1375 		tb_usb3_port_enable(down, false);
1376 		goto err_free;
1377 	}
1378 	tunnel->paths[TB_USB3_PATH_DOWN] = path;
1379 	tb_usb3_init_path(tunnel->paths[TB_USB3_PATH_DOWN]);
1380 
1381 	path = tb_path_discover(tunnel->dst_port, -1, down, TB_USB3_HOPID, NULL,
1382 				"USB3 Up");
1383 	if (!path)
1384 		goto err_deactivate;
1385 	tunnel->paths[TB_USB3_PATH_UP] = path;
1386 	tb_usb3_init_path(tunnel->paths[TB_USB3_PATH_UP]);
1387 
1388 	/* Validate that the tunnel is complete */
1389 	if (!tb_port_is_usb3_up(tunnel->dst_port)) {
1390 		tb_port_warn(tunnel->dst_port,
1391 			     "path does not end on an USB3 adapter, cleaning up\n");
1392 		goto err_deactivate;
1393 	}
1394 
1395 	if (down != tunnel->src_port) {
1396 		tb_tunnel_warn(tunnel, "path is not complete, cleaning up\n");
1397 		goto err_deactivate;
1398 	}
1399 
1400 	if (!tb_usb3_port_is_enabled(tunnel->dst_port)) {
1401 		tb_tunnel_warn(tunnel,
1402 			       "tunnel is not fully activated, cleaning up\n");
1403 		goto err_deactivate;
1404 	}
1405 
1406 	if (!tb_route(down->sw)) {
1407 		int ret;
1408 
1409 		/*
1410 		 * Read the initial bandwidth allocation for the first
1411 		 * hop tunnel.
1412 		 */
1413 		ret = usb4_usb3_port_allocated_bandwidth(down,
1414 			&tunnel->allocated_up, &tunnel->allocated_down);
1415 		if (ret)
1416 			goto err_deactivate;
1417 
1418 		tb_tunnel_dbg(tunnel, "currently allocated bandwidth %d/%d Mb/s\n",
1419 			      tunnel->allocated_up, tunnel->allocated_down);
1420 
1421 		tunnel->init = tb_usb3_init;
1422 		tunnel->consumed_bandwidth = tb_usb3_consumed_bandwidth;
1423 		tunnel->release_unused_bandwidth =
1424 			tb_usb3_release_unused_bandwidth;
1425 		tunnel->reclaim_available_bandwidth =
1426 			tb_usb3_reclaim_available_bandwidth;
1427 	}
1428 
1429 	tb_tunnel_dbg(tunnel, "discovered\n");
1430 	return tunnel;
1431 
1432 err_deactivate:
1433 	tb_tunnel_deactivate(tunnel);
1434 err_free:
1435 	tb_tunnel_free(tunnel);
1436 
1437 	return NULL;
1438 }
1439 
1440 /**
1441  * tb_tunnel_alloc_usb3() - allocate a USB3 tunnel
1442  * @tb: Pointer to the domain structure
1443  * @up: USB3 upstream adapter port
1444  * @down: USB3 downstream adapter port
1445  * @max_up: Maximum available upstream bandwidth for the USB3 tunnel (%0
1446  *	    if not limited).
1447  * @max_down: Maximum available downstream bandwidth for the USB3 tunnel
1448  *	      (%0 if not limited).
1449  *
1450  * Allocate an USB3 tunnel. The ports must be of type @TB_TYPE_USB3_UP and
1451  * @TB_TYPE_USB3_DOWN.
1452  *
1453  * Return: Returns a tb_tunnel on success or %NULL on failure.
1454  */
1455 struct tb_tunnel *tb_tunnel_alloc_usb3(struct tb *tb, struct tb_port *up,
1456 				       struct tb_port *down, int max_up,
1457 				       int max_down)
1458 {
1459 	struct tb_tunnel *tunnel;
1460 	struct tb_path *path;
1461 	int max_rate = 0;
1462 
1463 	/*
1464 	 * Check that we have enough bandwidth available for the new
1465 	 * USB3 tunnel.
1466 	 */
1467 	if (max_up > 0 || max_down > 0) {
1468 		max_rate = tb_usb3_max_link_rate(down, up);
1469 		if (max_rate < 0)
1470 			return NULL;
1471 
1472 		/* Only 90% can be allocated for USB3 isochronous transfers */
1473 		max_rate = max_rate * 90 / 100;
1474 		tb_port_dbg(up, "required bandwidth for USB3 tunnel %d Mb/s\n",
1475 			    max_rate);
1476 
1477 		if (max_rate > max_up || max_rate > max_down) {
1478 			tb_port_warn(up, "not enough bandwidth for USB3 tunnel\n");
1479 			return NULL;
1480 		}
1481 	}
1482 
1483 	tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_USB3);
1484 	if (!tunnel)
1485 		return NULL;
1486 
1487 	tunnel->activate = tb_usb3_activate;
1488 	tunnel->src_port = down;
1489 	tunnel->dst_port = up;
1490 	tunnel->max_up = max_up;
1491 	tunnel->max_down = max_down;
1492 
1493 	path = tb_path_alloc(tb, down, TB_USB3_HOPID, up, TB_USB3_HOPID, 0,
1494 			     "USB3 Down");
1495 	if (!path) {
1496 		tb_tunnel_free(tunnel);
1497 		return NULL;
1498 	}
1499 	tb_usb3_init_path(path);
1500 	tunnel->paths[TB_USB3_PATH_DOWN] = path;
1501 
1502 	path = tb_path_alloc(tb, up, TB_USB3_HOPID, down, TB_USB3_HOPID, 0,
1503 			     "USB3 Up");
1504 	if (!path) {
1505 		tb_tunnel_free(tunnel);
1506 		return NULL;
1507 	}
1508 	tb_usb3_init_path(path);
1509 	tunnel->paths[TB_USB3_PATH_UP] = path;
1510 
1511 	if (!tb_route(down->sw)) {
1512 		tunnel->allocated_up = max_rate;
1513 		tunnel->allocated_down = max_rate;
1514 
1515 		tunnel->init = tb_usb3_init;
1516 		tunnel->consumed_bandwidth = tb_usb3_consumed_bandwidth;
1517 		tunnel->release_unused_bandwidth =
1518 			tb_usb3_release_unused_bandwidth;
1519 		tunnel->reclaim_available_bandwidth =
1520 			tb_usb3_reclaim_available_bandwidth;
1521 	}
1522 
1523 	return tunnel;
1524 }
1525 
1526 /**
1527  * tb_tunnel_free() - free a tunnel
1528  * @tunnel: Tunnel to be freed
1529  *
1530  * Frees a tunnel. The tunnel does not need to be deactivated.
1531  */
1532 void tb_tunnel_free(struct tb_tunnel *tunnel)
1533 {
1534 	int i;
1535 
1536 	if (!tunnel)
1537 		return;
1538 
1539 	if (tunnel->deinit)
1540 		tunnel->deinit(tunnel);
1541 
1542 	for (i = 0; i < tunnel->npaths; i++) {
1543 		if (tunnel->paths[i])
1544 			tb_path_free(tunnel->paths[i]);
1545 	}
1546 
1547 	kfree(tunnel->paths);
1548 	kfree(tunnel);
1549 }
1550 
1551 /**
1552  * tb_tunnel_is_invalid - check whether an activated path is still valid
1553  * @tunnel: Tunnel to check
1554  */
1555 bool tb_tunnel_is_invalid(struct tb_tunnel *tunnel)
1556 {
1557 	int i;
1558 
1559 	for (i = 0; i < tunnel->npaths; i++) {
1560 		WARN_ON(!tunnel->paths[i]->activated);
1561 		if (tb_path_is_invalid(tunnel->paths[i]))
1562 			return true;
1563 	}
1564 
1565 	return false;
1566 }
1567 
1568 /**
1569  * tb_tunnel_restart() - activate a tunnel after a hardware reset
1570  * @tunnel: Tunnel to restart
1571  *
1572  * Return: 0 on success and negative errno in case if failure
1573  */
1574 int tb_tunnel_restart(struct tb_tunnel *tunnel)
1575 {
1576 	int res, i;
1577 
1578 	tb_tunnel_dbg(tunnel, "activating\n");
1579 
1580 	/*
1581 	 * Make sure all paths are properly disabled before enabling
1582 	 * them again.
1583 	 */
1584 	for (i = 0; i < tunnel->npaths; i++) {
1585 		if (tunnel->paths[i]->activated) {
1586 			tb_path_deactivate(tunnel->paths[i]);
1587 			tunnel->paths[i]->activated = false;
1588 		}
1589 	}
1590 
1591 	if (tunnel->init) {
1592 		res = tunnel->init(tunnel);
1593 		if (res)
1594 			return res;
1595 	}
1596 
1597 	for (i = 0; i < tunnel->npaths; i++) {
1598 		res = tb_path_activate(tunnel->paths[i]);
1599 		if (res)
1600 			goto err;
1601 	}
1602 
1603 	if (tunnel->activate) {
1604 		res = tunnel->activate(tunnel, true);
1605 		if (res)
1606 			goto err;
1607 	}
1608 
1609 	return 0;
1610 
1611 err:
1612 	tb_tunnel_warn(tunnel, "activation failed\n");
1613 	tb_tunnel_deactivate(tunnel);
1614 	return res;
1615 }
1616 
1617 /**
1618  * tb_tunnel_activate() - activate a tunnel
1619  * @tunnel: Tunnel to activate
1620  *
1621  * Return: Returns 0 on success or an error code on failure.
1622  */
1623 int tb_tunnel_activate(struct tb_tunnel *tunnel)
1624 {
1625 	int i;
1626 
1627 	for (i = 0; i < tunnel->npaths; i++) {
1628 		if (tunnel->paths[i]->activated) {
1629 			tb_tunnel_WARN(tunnel,
1630 				       "trying to activate an already activated tunnel\n");
1631 			return -EINVAL;
1632 		}
1633 	}
1634 
1635 	return tb_tunnel_restart(tunnel);
1636 }
1637 
1638 /**
1639  * tb_tunnel_deactivate() - deactivate a tunnel
1640  * @tunnel: Tunnel to deactivate
1641  */
1642 void tb_tunnel_deactivate(struct tb_tunnel *tunnel)
1643 {
1644 	int i;
1645 
1646 	tb_tunnel_dbg(tunnel, "deactivating\n");
1647 
1648 	if (tunnel->activate)
1649 		tunnel->activate(tunnel, false);
1650 
1651 	for (i = 0; i < tunnel->npaths; i++) {
1652 		if (tunnel->paths[i] && tunnel->paths[i]->activated)
1653 			tb_path_deactivate(tunnel->paths[i]);
1654 	}
1655 }
1656 
1657 /**
1658  * tb_tunnel_port_on_path() - Does the tunnel go through port
1659  * @tunnel: Tunnel to check
1660  * @port: Port to check
1661  *
1662  * Returns true if @tunnel goes through @port (direction does not matter),
1663  * false otherwise.
1664  */
1665 bool tb_tunnel_port_on_path(const struct tb_tunnel *tunnel,
1666 			    const struct tb_port *port)
1667 {
1668 	int i;
1669 
1670 	for (i = 0; i < tunnel->npaths; i++) {
1671 		if (!tunnel->paths[i])
1672 			continue;
1673 
1674 		if (tb_path_port_on_path(tunnel->paths[i], port))
1675 			return true;
1676 	}
1677 
1678 	return false;
1679 }
1680 
1681 static bool tb_tunnel_is_active(const struct tb_tunnel *tunnel)
1682 {
1683 	int i;
1684 
1685 	for (i = 0; i < tunnel->npaths; i++) {
1686 		if (!tunnel->paths[i])
1687 			return false;
1688 		if (!tunnel->paths[i]->activated)
1689 			return false;
1690 	}
1691 
1692 	return true;
1693 }
1694 
1695 /**
1696  * tb_tunnel_consumed_bandwidth() - Return bandwidth consumed by the tunnel
1697  * @tunnel: Tunnel to check
1698  * @consumed_up: Consumed bandwidth in Mb/s from @dst_port to @src_port.
1699  *		 Can be %NULL.
1700  * @consumed_down: Consumed bandwidth in Mb/s from @src_port to @dst_port.
1701  *		   Can be %NULL.
1702  *
1703  * Stores the amount of isochronous bandwidth @tunnel consumes in
1704  * @consumed_up and @consumed_down. In case of success returns %0,
1705  * negative errno otherwise.
1706  */
1707 int tb_tunnel_consumed_bandwidth(struct tb_tunnel *tunnel, int *consumed_up,
1708 				 int *consumed_down)
1709 {
1710 	int up_bw = 0, down_bw = 0;
1711 
1712 	if (!tb_tunnel_is_active(tunnel))
1713 		goto out;
1714 
1715 	if (tunnel->consumed_bandwidth) {
1716 		int ret;
1717 
1718 		ret = tunnel->consumed_bandwidth(tunnel, &up_bw, &down_bw);
1719 		if (ret)
1720 			return ret;
1721 
1722 		tb_tunnel_dbg(tunnel, "consumed bandwidth %d/%d Mb/s\n", up_bw,
1723 			      down_bw);
1724 	}
1725 
1726 out:
1727 	if (consumed_up)
1728 		*consumed_up = up_bw;
1729 	if (consumed_down)
1730 		*consumed_down = down_bw;
1731 
1732 	return 0;
1733 }
1734 
1735 /**
1736  * tb_tunnel_release_unused_bandwidth() - Release unused bandwidth
1737  * @tunnel: Tunnel whose unused bandwidth to release
1738  *
1739  * If tunnel supports dynamic bandwidth management (USB3 tunnels at the
1740  * moment) this function makes it to release all the unused bandwidth.
1741  *
1742  * Returns %0 in case of success and negative errno otherwise.
1743  */
1744 int tb_tunnel_release_unused_bandwidth(struct tb_tunnel *tunnel)
1745 {
1746 	if (!tb_tunnel_is_active(tunnel))
1747 		return 0;
1748 
1749 	if (tunnel->release_unused_bandwidth) {
1750 		int ret;
1751 
1752 		ret = tunnel->release_unused_bandwidth(tunnel);
1753 		if (ret)
1754 			return ret;
1755 	}
1756 
1757 	return 0;
1758 }
1759 
1760 /**
1761  * tb_tunnel_reclaim_available_bandwidth() - Reclaim available bandwidth
1762  * @tunnel: Tunnel reclaiming available bandwidth
1763  * @available_up: Available upstream bandwidth (in Mb/s)
1764  * @available_down: Available downstream bandwidth (in Mb/s)
1765  *
1766  * Reclaims bandwidth from @available_up and @available_down and updates
1767  * the variables accordingly (e.g decreases both according to what was
1768  * reclaimed by the tunnel). If nothing was reclaimed the values are
1769  * kept as is.
1770  */
1771 void tb_tunnel_reclaim_available_bandwidth(struct tb_tunnel *tunnel,
1772 					   int *available_up,
1773 					   int *available_down)
1774 {
1775 	if (!tb_tunnel_is_active(tunnel))
1776 		return;
1777 
1778 	if (tunnel->reclaim_available_bandwidth)
1779 		tunnel->reclaim_available_bandwidth(tunnel, available_up,
1780 						    available_down);
1781 }
1782