xref: /linux/drivers/thunderbolt/tunnel.c (revision a4eb44a6435d6d8f9e642407a4a06f65eb90ca04)
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  * @alloc_hopid: Allocate HopIDs from visited ports
211  *
212  * If @down adapter is active, follows the tunnel to the PCIe upstream
213  * adapter and back. Returns the discovered tunnel or %NULL if there was
214  * no tunnel.
215  */
216 struct tb_tunnel *tb_tunnel_discover_pci(struct tb *tb, struct tb_port *down,
217 					 bool alloc_hopid)
218 {
219 	struct tb_tunnel *tunnel;
220 	struct tb_path *path;
221 
222 	if (!tb_pci_port_is_enabled(down))
223 		return NULL;
224 
225 	tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_PCI);
226 	if (!tunnel)
227 		return NULL;
228 
229 	tunnel->activate = tb_pci_activate;
230 	tunnel->src_port = down;
231 
232 	/*
233 	 * Discover both paths even if they are not complete. We will
234 	 * clean them up by calling tb_tunnel_deactivate() below in that
235 	 * case.
236 	 */
237 	path = tb_path_discover(down, TB_PCI_HOPID, NULL, -1,
238 				&tunnel->dst_port, "PCIe Up", alloc_hopid);
239 	if (!path) {
240 		/* Just disable the downstream port */
241 		tb_pci_port_enable(down, false);
242 		goto err_free;
243 	}
244 	tunnel->paths[TB_PCI_PATH_UP] = path;
245 	if (tb_pci_init_path(tunnel->paths[TB_PCI_PATH_UP]))
246 		goto err_free;
247 
248 	path = tb_path_discover(tunnel->dst_port, -1, down, TB_PCI_HOPID, NULL,
249 				"PCIe Down", alloc_hopid);
250 	if (!path)
251 		goto err_deactivate;
252 	tunnel->paths[TB_PCI_PATH_DOWN] = path;
253 	if (tb_pci_init_path(tunnel->paths[TB_PCI_PATH_DOWN]))
254 		goto err_deactivate;
255 
256 	/* Validate that the tunnel is complete */
257 	if (!tb_port_is_pcie_up(tunnel->dst_port)) {
258 		tb_port_warn(tunnel->dst_port,
259 			     "path does not end on a PCIe adapter, cleaning up\n");
260 		goto err_deactivate;
261 	}
262 
263 	if (down != tunnel->src_port) {
264 		tb_tunnel_warn(tunnel, "path is not complete, cleaning up\n");
265 		goto err_deactivate;
266 	}
267 
268 	if (!tb_pci_port_is_enabled(tunnel->dst_port)) {
269 		tb_tunnel_warn(tunnel,
270 			       "tunnel is not fully activated, cleaning up\n");
271 		goto err_deactivate;
272 	}
273 
274 	tb_tunnel_dbg(tunnel, "discovered\n");
275 	return tunnel;
276 
277 err_deactivate:
278 	tb_tunnel_deactivate(tunnel);
279 err_free:
280 	tb_tunnel_free(tunnel);
281 
282 	return NULL;
283 }
284 
285 /**
286  * tb_tunnel_alloc_pci() - allocate a pci tunnel
287  * @tb: Pointer to the domain structure
288  * @up: PCIe upstream adapter port
289  * @down: PCIe downstream adapter port
290  *
291  * Allocate a PCI tunnel. The ports must be of type TB_TYPE_PCIE_UP and
292  * TB_TYPE_PCIE_DOWN.
293  *
294  * Return: Returns a tb_tunnel on success or NULL on failure.
295  */
296 struct tb_tunnel *tb_tunnel_alloc_pci(struct tb *tb, struct tb_port *up,
297 				      struct tb_port *down)
298 {
299 	struct tb_tunnel *tunnel;
300 	struct tb_path *path;
301 
302 	tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_PCI);
303 	if (!tunnel)
304 		return NULL;
305 
306 	tunnel->activate = tb_pci_activate;
307 	tunnel->src_port = down;
308 	tunnel->dst_port = up;
309 
310 	path = tb_path_alloc(tb, down, TB_PCI_HOPID, up, TB_PCI_HOPID, 0,
311 			     "PCIe Down");
312 	if (!path)
313 		goto err_free;
314 	tunnel->paths[TB_PCI_PATH_DOWN] = path;
315 	if (tb_pci_init_path(path))
316 		goto err_free;
317 
318 	path = tb_path_alloc(tb, up, TB_PCI_HOPID, down, TB_PCI_HOPID, 0,
319 			     "PCIe Up");
320 	if (!path)
321 		goto err_free;
322 	tunnel->paths[TB_PCI_PATH_UP] = path;
323 	if (tb_pci_init_path(path))
324 		goto err_free;
325 
326 	return tunnel;
327 
328 err_free:
329 	tb_tunnel_free(tunnel);
330 	return NULL;
331 }
332 
333 static bool tb_dp_is_usb4(const struct tb_switch *sw)
334 {
335 	/* Titan Ridge DP adapters need the same treatment as USB4 */
336 	return tb_switch_is_usb4(sw) || tb_switch_is_titan_ridge(sw);
337 }
338 
339 static int tb_dp_cm_handshake(struct tb_port *in, struct tb_port *out)
340 {
341 	int timeout = 10;
342 	u32 val;
343 	int ret;
344 
345 	/* Both ends need to support this */
346 	if (!tb_dp_is_usb4(in->sw) || !tb_dp_is_usb4(out->sw))
347 		return 0;
348 
349 	ret = tb_port_read(out, &val, TB_CFG_PORT,
350 			   out->cap_adap + DP_STATUS_CTRL, 1);
351 	if (ret)
352 		return ret;
353 
354 	val |= DP_STATUS_CTRL_UF | DP_STATUS_CTRL_CMHS;
355 
356 	ret = tb_port_write(out, &val, TB_CFG_PORT,
357 			    out->cap_adap + DP_STATUS_CTRL, 1);
358 	if (ret)
359 		return ret;
360 
361 	do {
362 		ret = tb_port_read(out, &val, TB_CFG_PORT,
363 				   out->cap_adap + DP_STATUS_CTRL, 1);
364 		if (ret)
365 			return ret;
366 		if (!(val & DP_STATUS_CTRL_CMHS))
367 			return 0;
368 		usleep_range(10, 100);
369 	} while (timeout--);
370 
371 	return -ETIMEDOUT;
372 }
373 
374 static inline u32 tb_dp_cap_get_rate(u32 val)
375 {
376 	u32 rate = (val & DP_COMMON_CAP_RATE_MASK) >> DP_COMMON_CAP_RATE_SHIFT;
377 
378 	switch (rate) {
379 	case DP_COMMON_CAP_RATE_RBR:
380 		return 1620;
381 	case DP_COMMON_CAP_RATE_HBR:
382 		return 2700;
383 	case DP_COMMON_CAP_RATE_HBR2:
384 		return 5400;
385 	case DP_COMMON_CAP_RATE_HBR3:
386 		return 8100;
387 	default:
388 		return 0;
389 	}
390 }
391 
392 static inline u32 tb_dp_cap_set_rate(u32 val, u32 rate)
393 {
394 	val &= ~DP_COMMON_CAP_RATE_MASK;
395 	switch (rate) {
396 	default:
397 		WARN(1, "invalid rate %u passed, defaulting to 1620 MB/s\n", rate);
398 		fallthrough;
399 	case 1620:
400 		val |= DP_COMMON_CAP_RATE_RBR << DP_COMMON_CAP_RATE_SHIFT;
401 		break;
402 	case 2700:
403 		val |= DP_COMMON_CAP_RATE_HBR << DP_COMMON_CAP_RATE_SHIFT;
404 		break;
405 	case 5400:
406 		val |= DP_COMMON_CAP_RATE_HBR2 << DP_COMMON_CAP_RATE_SHIFT;
407 		break;
408 	case 8100:
409 		val |= DP_COMMON_CAP_RATE_HBR3 << DP_COMMON_CAP_RATE_SHIFT;
410 		break;
411 	}
412 	return val;
413 }
414 
415 static inline u32 tb_dp_cap_get_lanes(u32 val)
416 {
417 	u32 lanes = (val & DP_COMMON_CAP_LANES_MASK) >> DP_COMMON_CAP_LANES_SHIFT;
418 
419 	switch (lanes) {
420 	case DP_COMMON_CAP_1_LANE:
421 		return 1;
422 	case DP_COMMON_CAP_2_LANES:
423 		return 2;
424 	case DP_COMMON_CAP_4_LANES:
425 		return 4;
426 	default:
427 		return 0;
428 	}
429 }
430 
431 static inline u32 tb_dp_cap_set_lanes(u32 val, u32 lanes)
432 {
433 	val &= ~DP_COMMON_CAP_LANES_MASK;
434 	switch (lanes) {
435 	default:
436 		WARN(1, "invalid number of lanes %u passed, defaulting to 1\n",
437 		     lanes);
438 		fallthrough;
439 	case 1:
440 		val |= DP_COMMON_CAP_1_LANE << DP_COMMON_CAP_LANES_SHIFT;
441 		break;
442 	case 2:
443 		val |= DP_COMMON_CAP_2_LANES << DP_COMMON_CAP_LANES_SHIFT;
444 		break;
445 	case 4:
446 		val |= DP_COMMON_CAP_4_LANES << DP_COMMON_CAP_LANES_SHIFT;
447 		break;
448 	}
449 	return val;
450 }
451 
452 static unsigned int tb_dp_bandwidth(unsigned int rate, unsigned int lanes)
453 {
454 	/* Tunneling removes the DP 8b/10b encoding */
455 	return rate * lanes * 8 / 10;
456 }
457 
458 static int tb_dp_reduce_bandwidth(int max_bw, u32 in_rate, u32 in_lanes,
459 				  u32 out_rate, u32 out_lanes, u32 *new_rate,
460 				  u32 *new_lanes)
461 {
462 	static const u32 dp_bw[][2] = {
463 		/* Mb/s, lanes */
464 		{ 8100, 4 }, /* 25920 Mb/s */
465 		{ 5400, 4 }, /* 17280 Mb/s */
466 		{ 8100, 2 }, /* 12960 Mb/s */
467 		{ 2700, 4 }, /* 8640 Mb/s */
468 		{ 5400, 2 }, /* 8640 Mb/s */
469 		{ 8100, 1 }, /* 6480 Mb/s */
470 		{ 1620, 4 }, /* 5184 Mb/s */
471 		{ 5400, 1 }, /* 4320 Mb/s */
472 		{ 2700, 2 }, /* 4320 Mb/s */
473 		{ 1620, 2 }, /* 2592 Mb/s */
474 		{ 2700, 1 }, /* 2160 Mb/s */
475 		{ 1620, 1 }, /* 1296 Mb/s */
476 	};
477 	unsigned int i;
478 
479 	/*
480 	 * Find a combination that can fit into max_bw and does not
481 	 * exceed the maximum rate and lanes supported by the DP OUT and
482 	 * DP IN adapters.
483 	 */
484 	for (i = 0; i < ARRAY_SIZE(dp_bw); i++) {
485 		if (dp_bw[i][0] > out_rate || dp_bw[i][1] > out_lanes)
486 			continue;
487 
488 		if (dp_bw[i][0] > in_rate || dp_bw[i][1] > in_lanes)
489 			continue;
490 
491 		if (tb_dp_bandwidth(dp_bw[i][0], dp_bw[i][1]) <= max_bw) {
492 			*new_rate = dp_bw[i][0];
493 			*new_lanes = dp_bw[i][1];
494 			return 0;
495 		}
496 	}
497 
498 	return -ENOSR;
499 }
500 
501 static int tb_dp_xchg_caps(struct tb_tunnel *tunnel)
502 {
503 	u32 out_dp_cap, out_rate, out_lanes, in_dp_cap, in_rate, in_lanes, bw;
504 	struct tb_port *out = tunnel->dst_port;
505 	struct tb_port *in = tunnel->src_port;
506 	int ret, max_bw;
507 
508 	/*
509 	 * Copy DP_LOCAL_CAP register to DP_REMOTE_CAP register for
510 	 * newer generation hardware.
511 	 */
512 	if (in->sw->generation < 2 || out->sw->generation < 2)
513 		return 0;
514 
515 	/*
516 	 * Perform connection manager handshake between IN and OUT ports
517 	 * before capabilities exchange can take place.
518 	 */
519 	ret = tb_dp_cm_handshake(in, out);
520 	if (ret)
521 		return ret;
522 
523 	/* Read both DP_LOCAL_CAP registers */
524 	ret = tb_port_read(in, &in_dp_cap, TB_CFG_PORT,
525 			   in->cap_adap + DP_LOCAL_CAP, 1);
526 	if (ret)
527 		return ret;
528 
529 	ret = tb_port_read(out, &out_dp_cap, TB_CFG_PORT,
530 			   out->cap_adap + DP_LOCAL_CAP, 1);
531 	if (ret)
532 		return ret;
533 
534 	/* Write IN local caps to OUT remote caps */
535 	ret = tb_port_write(out, &in_dp_cap, TB_CFG_PORT,
536 			    out->cap_adap + DP_REMOTE_CAP, 1);
537 	if (ret)
538 		return ret;
539 
540 	in_rate = tb_dp_cap_get_rate(in_dp_cap);
541 	in_lanes = tb_dp_cap_get_lanes(in_dp_cap);
542 	tb_port_dbg(in, "maximum supported bandwidth %u Mb/s x%u = %u Mb/s\n",
543 		    in_rate, in_lanes, tb_dp_bandwidth(in_rate, in_lanes));
544 
545 	/*
546 	 * If the tunnel bandwidth is limited (max_bw is set) then see
547 	 * if we need to reduce bandwidth to fit there.
548 	 */
549 	out_rate = tb_dp_cap_get_rate(out_dp_cap);
550 	out_lanes = tb_dp_cap_get_lanes(out_dp_cap);
551 	bw = tb_dp_bandwidth(out_rate, out_lanes);
552 	tb_port_dbg(out, "maximum supported bandwidth %u Mb/s x%u = %u Mb/s\n",
553 		    out_rate, out_lanes, bw);
554 
555 	if (in->sw->config.depth < out->sw->config.depth)
556 		max_bw = tunnel->max_down;
557 	else
558 		max_bw = tunnel->max_up;
559 
560 	if (max_bw && bw > max_bw) {
561 		u32 new_rate, new_lanes, new_bw;
562 
563 		ret = tb_dp_reduce_bandwidth(max_bw, in_rate, in_lanes,
564 					     out_rate, out_lanes, &new_rate,
565 					     &new_lanes);
566 		if (ret) {
567 			tb_port_info(out, "not enough bandwidth for DP tunnel\n");
568 			return ret;
569 		}
570 
571 		new_bw = tb_dp_bandwidth(new_rate, new_lanes);
572 		tb_port_dbg(out, "bandwidth reduced to %u Mb/s x%u = %u Mb/s\n",
573 			    new_rate, new_lanes, new_bw);
574 
575 		/*
576 		 * Set new rate and number of lanes before writing it to
577 		 * the IN port remote caps.
578 		 */
579 		out_dp_cap = tb_dp_cap_set_rate(out_dp_cap, new_rate);
580 		out_dp_cap = tb_dp_cap_set_lanes(out_dp_cap, new_lanes);
581 	}
582 
583 	return tb_port_write(in, &out_dp_cap, TB_CFG_PORT,
584 			     in->cap_adap + DP_REMOTE_CAP, 1);
585 }
586 
587 static int tb_dp_activate(struct tb_tunnel *tunnel, bool active)
588 {
589 	int ret;
590 
591 	if (active) {
592 		struct tb_path **paths;
593 		int last;
594 
595 		paths = tunnel->paths;
596 		last = paths[TB_DP_VIDEO_PATH_OUT]->path_length - 1;
597 
598 		tb_dp_port_set_hops(tunnel->src_port,
599 			paths[TB_DP_VIDEO_PATH_OUT]->hops[0].in_hop_index,
600 			paths[TB_DP_AUX_PATH_OUT]->hops[0].in_hop_index,
601 			paths[TB_DP_AUX_PATH_IN]->hops[last].next_hop_index);
602 
603 		tb_dp_port_set_hops(tunnel->dst_port,
604 			paths[TB_DP_VIDEO_PATH_OUT]->hops[last].next_hop_index,
605 			paths[TB_DP_AUX_PATH_IN]->hops[0].in_hop_index,
606 			paths[TB_DP_AUX_PATH_OUT]->hops[last].next_hop_index);
607 	} else {
608 		tb_dp_port_hpd_clear(tunnel->src_port);
609 		tb_dp_port_set_hops(tunnel->src_port, 0, 0, 0);
610 		if (tb_port_is_dpout(tunnel->dst_port))
611 			tb_dp_port_set_hops(tunnel->dst_port, 0, 0, 0);
612 	}
613 
614 	ret = tb_dp_port_enable(tunnel->src_port, active);
615 	if (ret)
616 		return ret;
617 
618 	if (tb_port_is_dpout(tunnel->dst_port))
619 		return tb_dp_port_enable(tunnel->dst_port, active);
620 
621 	return 0;
622 }
623 
624 static int tb_dp_consumed_bandwidth(struct tb_tunnel *tunnel, int *consumed_up,
625 				    int *consumed_down)
626 {
627 	struct tb_port *in = tunnel->src_port;
628 	const struct tb_switch *sw = in->sw;
629 	u32 val, rate = 0, lanes = 0;
630 	int ret;
631 
632 	if (tb_dp_is_usb4(sw)) {
633 		int timeout = 20;
634 
635 		/*
636 		 * Wait for DPRX done. Normally it should be already set
637 		 * for active tunnel.
638 		 */
639 		do {
640 			ret = tb_port_read(in, &val, TB_CFG_PORT,
641 					   in->cap_adap + DP_COMMON_CAP, 1);
642 			if (ret)
643 				return ret;
644 
645 			if (val & DP_COMMON_CAP_DPRX_DONE) {
646 				rate = tb_dp_cap_get_rate(val);
647 				lanes = tb_dp_cap_get_lanes(val);
648 				break;
649 			}
650 			msleep(250);
651 		} while (timeout--);
652 
653 		if (!timeout)
654 			return -ETIMEDOUT;
655 	} else if (sw->generation >= 2) {
656 		/*
657 		 * Read from the copied remote cap so that we take into
658 		 * account if capabilities were reduced during exchange.
659 		 */
660 		ret = tb_port_read(in, &val, TB_CFG_PORT,
661 				   in->cap_adap + DP_REMOTE_CAP, 1);
662 		if (ret)
663 			return ret;
664 
665 		rate = tb_dp_cap_get_rate(val);
666 		lanes = tb_dp_cap_get_lanes(val);
667 	} else {
668 		/* No bandwidth management for legacy devices  */
669 		*consumed_up = 0;
670 		*consumed_down = 0;
671 		return 0;
672 	}
673 
674 	if (in->sw->config.depth < tunnel->dst_port->sw->config.depth) {
675 		*consumed_up = 0;
676 		*consumed_down = tb_dp_bandwidth(rate, lanes);
677 	} else {
678 		*consumed_up = tb_dp_bandwidth(rate, lanes);
679 		*consumed_down = 0;
680 	}
681 
682 	return 0;
683 }
684 
685 static void tb_dp_init_aux_credits(struct tb_path_hop *hop)
686 {
687 	struct tb_port *port = hop->in_port;
688 	struct tb_switch *sw = port->sw;
689 
690 	if (tb_port_use_credit_allocation(port))
691 		hop->initial_credits = sw->min_dp_aux_credits;
692 	else
693 		hop->initial_credits = 1;
694 }
695 
696 static void tb_dp_init_aux_path(struct tb_path *path)
697 {
698 	struct tb_path_hop *hop;
699 
700 	path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
701 	path->egress_shared_buffer = TB_PATH_NONE;
702 	path->ingress_fc_enable = TB_PATH_ALL;
703 	path->ingress_shared_buffer = TB_PATH_NONE;
704 	path->priority = 2;
705 	path->weight = 1;
706 
707 	tb_path_for_each_hop(path, hop)
708 		tb_dp_init_aux_credits(hop);
709 }
710 
711 static int tb_dp_init_video_credits(struct tb_path_hop *hop)
712 {
713 	struct tb_port *port = hop->in_port;
714 	struct tb_switch *sw = port->sw;
715 
716 	if (tb_port_use_credit_allocation(port)) {
717 		unsigned int nfc_credits;
718 		size_t max_dp_streams;
719 
720 		tb_available_credits(port, &max_dp_streams);
721 		/*
722 		 * Read the number of currently allocated NFC credits
723 		 * from the lane adapter. Since we only use them for DP
724 		 * tunneling we can use that to figure out how many DP
725 		 * tunnels already go through the lane adapter.
726 		 */
727 		nfc_credits = port->config.nfc_credits &
728 				ADP_CS_4_NFC_BUFFERS_MASK;
729 		if (nfc_credits / sw->min_dp_main_credits > max_dp_streams)
730 			return -ENOSPC;
731 
732 		hop->nfc_credits = sw->min_dp_main_credits;
733 	} else {
734 		hop->nfc_credits = min(port->total_credits - 2, 12U);
735 	}
736 
737 	return 0;
738 }
739 
740 static int tb_dp_init_video_path(struct tb_path *path)
741 {
742 	struct tb_path_hop *hop;
743 
744 	path->egress_fc_enable = TB_PATH_NONE;
745 	path->egress_shared_buffer = TB_PATH_NONE;
746 	path->ingress_fc_enable = TB_PATH_NONE;
747 	path->ingress_shared_buffer = TB_PATH_NONE;
748 	path->priority = 1;
749 	path->weight = 1;
750 
751 	tb_path_for_each_hop(path, hop) {
752 		int ret;
753 
754 		ret = tb_dp_init_video_credits(hop);
755 		if (ret)
756 			return ret;
757 	}
758 
759 	return 0;
760 }
761 
762 /**
763  * tb_tunnel_discover_dp() - Discover existing Display Port tunnels
764  * @tb: Pointer to the domain structure
765  * @in: DP in adapter
766  * @alloc_hopid: Allocate HopIDs from visited ports
767  *
768  * If @in adapter is active, follows the tunnel to the DP out adapter
769  * and back. Returns the discovered tunnel or %NULL if there was no
770  * tunnel.
771  *
772  * Return: DP tunnel or %NULL if no tunnel found.
773  */
774 struct tb_tunnel *tb_tunnel_discover_dp(struct tb *tb, struct tb_port *in,
775 					bool alloc_hopid)
776 {
777 	struct tb_tunnel *tunnel;
778 	struct tb_port *port;
779 	struct tb_path *path;
780 
781 	if (!tb_dp_port_is_enabled(in))
782 		return NULL;
783 
784 	tunnel = tb_tunnel_alloc(tb, 3, TB_TUNNEL_DP);
785 	if (!tunnel)
786 		return NULL;
787 
788 	tunnel->init = tb_dp_xchg_caps;
789 	tunnel->activate = tb_dp_activate;
790 	tunnel->consumed_bandwidth = tb_dp_consumed_bandwidth;
791 	tunnel->src_port = in;
792 
793 	path = tb_path_discover(in, TB_DP_VIDEO_HOPID, NULL, -1,
794 				&tunnel->dst_port, "Video", alloc_hopid);
795 	if (!path) {
796 		/* Just disable the DP IN port */
797 		tb_dp_port_enable(in, false);
798 		goto err_free;
799 	}
800 	tunnel->paths[TB_DP_VIDEO_PATH_OUT] = path;
801 	if (tb_dp_init_video_path(tunnel->paths[TB_DP_VIDEO_PATH_OUT]))
802 		goto err_free;
803 
804 	path = tb_path_discover(in, TB_DP_AUX_TX_HOPID, NULL, -1, NULL, "AUX TX",
805 				alloc_hopid);
806 	if (!path)
807 		goto err_deactivate;
808 	tunnel->paths[TB_DP_AUX_PATH_OUT] = path;
809 	tb_dp_init_aux_path(tunnel->paths[TB_DP_AUX_PATH_OUT]);
810 
811 	path = tb_path_discover(tunnel->dst_port, -1, in, TB_DP_AUX_RX_HOPID,
812 				&port, "AUX RX", alloc_hopid);
813 	if (!path)
814 		goto err_deactivate;
815 	tunnel->paths[TB_DP_AUX_PATH_IN] = path;
816 	tb_dp_init_aux_path(tunnel->paths[TB_DP_AUX_PATH_IN]);
817 
818 	/* Validate that the tunnel is complete */
819 	if (!tb_port_is_dpout(tunnel->dst_port)) {
820 		tb_port_warn(in, "path does not end on a DP adapter, cleaning up\n");
821 		goto err_deactivate;
822 	}
823 
824 	if (!tb_dp_port_is_enabled(tunnel->dst_port))
825 		goto err_deactivate;
826 
827 	if (!tb_dp_port_hpd_is_active(tunnel->dst_port))
828 		goto err_deactivate;
829 
830 	if (port != tunnel->src_port) {
831 		tb_tunnel_warn(tunnel, "path is not complete, cleaning up\n");
832 		goto err_deactivate;
833 	}
834 
835 	tb_tunnel_dbg(tunnel, "discovered\n");
836 	return tunnel;
837 
838 err_deactivate:
839 	tb_tunnel_deactivate(tunnel);
840 err_free:
841 	tb_tunnel_free(tunnel);
842 
843 	return NULL;
844 }
845 
846 /**
847  * tb_tunnel_alloc_dp() - allocate a Display Port tunnel
848  * @tb: Pointer to the domain structure
849  * @in: DP in adapter port
850  * @out: DP out adapter port
851  * @max_up: Maximum available upstream bandwidth for the DP tunnel (%0
852  *	    if not limited)
853  * @max_down: Maximum available downstream bandwidth for the DP tunnel
854  *	      (%0 if not limited)
855  *
856  * Allocates a tunnel between @in and @out that is capable of tunneling
857  * Display Port traffic.
858  *
859  * Return: Returns a tb_tunnel on success or NULL on failure.
860  */
861 struct tb_tunnel *tb_tunnel_alloc_dp(struct tb *tb, struct tb_port *in,
862 				     struct tb_port *out, int max_up,
863 				     int max_down)
864 {
865 	struct tb_tunnel *tunnel;
866 	struct tb_path **paths;
867 	struct tb_path *path;
868 
869 	if (WARN_ON(!in->cap_adap || !out->cap_adap))
870 		return NULL;
871 
872 	tunnel = tb_tunnel_alloc(tb, 3, TB_TUNNEL_DP);
873 	if (!tunnel)
874 		return NULL;
875 
876 	tunnel->init = tb_dp_xchg_caps;
877 	tunnel->activate = tb_dp_activate;
878 	tunnel->consumed_bandwidth = tb_dp_consumed_bandwidth;
879 	tunnel->src_port = in;
880 	tunnel->dst_port = out;
881 	tunnel->max_up = max_up;
882 	tunnel->max_down = max_down;
883 
884 	paths = tunnel->paths;
885 
886 	path = tb_path_alloc(tb, in, TB_DP_VIDEO_HOPID, out, TB_DP_VIDEO_HOPID,
887 			     1, "Video");
888 	if (!path)
889 		goto err_free;
890 	tb_dp_init_video_path(path);
891 	paths[TB_DP_VIDEO_PATH_OUT] = path;
892 
893 	path = tb_path_alloc(tb, in, TB_DP_AUX_TX_HOPID, out,
894 			     TB_DP_AUX_TX_HOPID, 1, "AUX TX");
895 	if (!path)
896 		goto err_free;
897 	tb_dp_init_aux_path(path);
898 	paths[TB_DP_AUX_PATH_OUT] = path;
899 
900 	path = tb_path_alloc(tb, out, TB_DP_AUX_RX_HOPID, in,
901 			     TB_DP_AUX_RX_HOPID, 1, "AUX RX");
902 	if (!path)
903 		goto err_free;
904 	tb_dp_init_aux_path(path);
905 	paths[TB_DP_AUX_PATH_IN] = path;
906 
907 	return tunnel;
908 
909 err_free:
910 	tb_tunnel_free(tunnel);
911 	return NULL;
912 }
913 
914 static unsigned int tb_dma_available_credits(const struct tb_port *port)
915 {
916 	const struct tb_switch *sw = port->sw;
917 	int credits;
918 
919 	credits = tb_available_credits(port, NULL);
920 	if (tb_acpi_may_tunnel_pcie())
921 		credits -= sw->max_pcie_credits;
922 	credits -= port->dma_credits;
923 
924 	return credits > 0 ? credits : 0;
925 }
926 
927 static int tb_dma_reserve_credits(struct tb_path_hop *hop, unsigned int credits)
928 {
929 	struct tb_port *port = hop->in_port;
930 
931 	if (tb_port_use_credit_allocation(port)) {
932 		unsigned int available = tb_dma_available_credits(port);
933 
934 		/*
935 		 * Need to have at least TB_MIN_DMA_CREDITS, otherwise
936 		 * DMA path cannot be established.
937 		 */
938 		if (available < TB_MIN_DMA_CREDITS)
939 			return -ENOSPC;
940 
941 		while (credits > available)
942 			credits--;
943 
944 		tb_port_dbg(port, "reserving %u credits for DMA path\n",
945 			    credits);
946 
947 		port->dma_credits += credits;
948 	} else {
949 		if (tb_port_is_null(port))
950 			credits = port->bonded ? 14 : 6;
951 		else
952 			credits = min(port->total_credits, credits);
953 	}
954 
955 	hop->initial_credits = credits;
956 	return 0;
957 }
958 
959 /* Path from lane adapter to NHI */
960 static int tb_dma_init_rx_path(struct tb_path *path, unsigned int credits)
961 {
962 	struct tb_path_hop *hop;
963 	unsigned int i, tmp;
964 
965 	path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
966 	path->ingress_fc_enable = TB_PATH_ALL;
967 	path->egress_shared_buffer = TB_PATH_NONE;
968 	path->ingress_shared_buffer = TB_PATH_NONE;
969 	path->priority = 5;
970 	path->weight = 1;
971 	path->clear_fc = true;
972 
973 	/*
974 	 * First lane adapter is the one connected to the remote host.
975 	 * We don't tunnel other traffic over this link so can use all
976 	 * the credits (except the ones reserved for control traffic).
977 	 */
978 	hop = &path->hops[0];
979 	tmp = min(tb_usable_credits(hop->in_port), credits);
980 	hop->initial_credits = tmp;
981 	hop->in_port->dma_credits += tmp;
982 
983 	for (i = 1; i < path->path_length; i++) {
984 		int ret;
985 
986 		ret = tb_dma_reserve_credits(&path->hops[i], credits);
987 		if (ret)
988 			return ret;
989 	}
990 
991 	return 0;
992 }
993 
994 /* Path from NHI to lane adapter */
995 static int tb_dma_init_tx_path(struct tb_path *path, unsigned int credits)
996 {
997 	struct tb_path_hop *hop;
998 
999 	path->egress_fc_enable = TB_PATH_ALL;
1000 	path->ingress_fc_enable = TB_PATH_ALL;
1001 	path->egress_shared_buffer = TB_PATH_NONE;
1002 	path->ingress_shared_buffer = TB_PATH_NONE;
1003 	path->priority = 5;
1004 	path->weight = 1;
1005 	path->clear_fc = true;
1006 
1007 	tb_path_for_each_hop(path, hop) {
1008 		int ret;
1009 
1010 		ret = tb_dma_reserve_credits(hop, credits);
1011 		if (ret)
1012 			return ret;
1013 	}
1014 
1015 	return 0;
1016 }
1017 
1018 static void tb_dma_release_credits(struct tb_path_hop *hop)
1019 {
1020 	struct tb_port *port = hop->in_port;
1021 
1022 	if (tb_port_use_credit_allocation(port)) {
1023 		port->dma_credits -= hop->initial_credits;
1024 
1025 		tb_port_dbg(port, "released %u DMA path credits\n",
1026 			    hop->initial_credits);
1027 	}
1028 }
1029 
1030 static void tb_dma_deinit_path(struct tb_path *path)
1031 {
1032 	struct tb_path_hop *hop;
1033 
1034 	tb_path_for_each_hop(path, hop)
1035 		tb_dma_release_credits(hop);
1036 }
1037 
1038 static void tb_dma_deinit(struct tb_tunnel *tunnel)
1039 {
1040 	int i;
1041 
1042 	for (i = 0; i < tunnel->npaths; i++) {
1043 		if (!tunnel->paths[i])
1044 			continue;
1045 		tb_dma_deinit_path(tunnel->paths[i]);
1046 	}
1047 }
1048 
1049 /**
1050  * tb_tunnel_alloc_dma() - allocate a DMA tunnel
1051  * @tb: Pointer to the domain structure
1052  * @nhi: Host controller port
1053  * @dst: Destination null port which the other domain is connected to
1054  * @transmit_path: HopID used for transmitting packets
1055  * @transmit_ring: NHI ring number used to send packets towards the
1056  *		   other domain. Set to %-1 if TX path is not needed.
1057  * @receive_path: HopID used for receiving packets
1058  * @receive_ring: NHI ring number used to receive packets from the
1059  *		  other domain. Set to %-1 if RX path is not needed.
1060  *
1061  * Return: Returns a tb_tunnel on success or NULL on failure.
1062  */
1063 struct tb_tunnel *tb_tunnel_alloc_dma(struct tb *tb, struct tb_port *nhi,
1064 				      struct tb_port *dst, int transmit_path,
1065 				      int transmit_ring, int receive_path,
1066 				      int receive_ring)
1067 {
1068 	struct tb_tunnel *tunnel;
1069 	size_t npaths = 0, i = 0;
1070 	struct tb_path *path;
1071 	int credits;
1072 
1073 	if (receive_ring > 0)
1074 		npaths++;
1075 	if (transmit_ring > 0)
1076 		npaths++;
1077 
1078 	if (WARN_ON(!npaths))
1079 		return NULL;
1080 
1081 	tunnel = tb_tunnel_alloc(tb, npaths, TB_TUNNEL_DMA);
1082 	if (!tunnel)
1083 		return NULL;
1084 
1085 	tunnel->src_port = nhi;
1086 	tunnel->dst_port = dst;
1087 	tunnel->deinit = tb_dma_deinit;
1088 
1089 	credits = min_not_zero(TB_DMA_CREDITS, nhi->sw->max_dma_credits);
1090 
1091 	if (receive_ring > 0) {
1092 		path = tb_path_alloc(tb, dst, receive_path, nhi, receive_ring, 0,
1093 				     "DMA RX");
1094 		if (!path)
1095 			goto err_free;
1096 		tunnel->paths[i++] = path;
1097 		if (tb_dma_init_rx_path(path, credits)) {
1098 			tb_tunnel_dbg(tunnel, "not enough buffers for RX path\n");
1099 			goto err_free;
1100 		}
1101 	}
1102 
1103 	if (transmit_ring > 0) {
1104 		path = tb_path_alloc(tb, nhi, transmit_ring, dst, transmit_path, 0,
1105 				     "DMA TX");
1106 		if (!path)
1107 			goto err_free;
1108 		tunnel->paths[i++] = path;
1109 		if (tb_dma_init_tx_path(path, credits)) {
1110 			tb_tunnel_dbg(tunnel, "not enough buffers for TX path\n");
1111 			goto err_free;
1112 		}
1113 	}
1114 
1115 	return tunnel;
1116 
1117 err_free:
1118 	tb_tunnel_free(tunnel);
1119 	return NULL;
1120 }
1121 
1122 /**
1123  * tb_tunnel_match_dma() - Match DMA tunnel
1124  * @tunnel: Tunnel to match
1125  * @transmit_path: HopID used for transmitting packets. Pass %-1 to ignore.
1126  * @transmit_ring: NHI ring number used to send packets towards the
1127  *		   other domain. Pass %-1 to ignore.
1128  * @receive_path: HopID used for receiving packets. Pass %-1 to ignore.
1129  * @receive_ring: NHI ring number used to receive packets from the
1130  *		  other domain. Pass %-1 to ignore.
1131  *
1132  * This function can be used to match specific DMA tunnel, if there are
1133  * multiple DMA tunnels going through the same XDomain connection.
1134  * Returns true if there is match and false otherwise.
1135  */
1136 bool tb_tunnel_match_dma(const struct tb_tunnel *tunnel, int transmit_path,
1137 			 int transmit_ring, int receive_path, int receive_ring)
1138 {
1139 	const struct tb_path *tx_path = NULL, *rx_path = NULL;
1140 	int i;
1141 
1142 	if (!receive_ring || !transmit_ring)
1143 		return false;
1144 
1145 	for (i = 0; i < tunnel->npaths; i++) {
1146 		const struct tb_path *path = tunnel->paths[i];
1147 
1148 		if (!path)
1149 			continue;
1150 
1151 		if (tb_port_is_nhi(path->hops[0].in_port))
1152 			tx_path = path;
1153 		else if (tb_port_is_nhi(path->hops[path->path_length - 1].out_port))
1154 			rx_path = path;
1155 	}
1156 
1157 	if (transmit_ring > 0 || transmit_path > 0) {
1158 		if (!tx_path)
1159 			return false;
1160 		if (transmit_ring > 0 &&
1161 		    (tx_path->hops[0].in_hop_index != transmit_ring))
1162 			return false;
1163 		if (transmit_path > 0 &&
1164 		    (tx_path->hops[tx_path->path_length - 1].next_hop_index != transmit_path))
1165 			return false;
1166 	}
1167 
1168 	if (receive_ring > 0 || receive_path > 0) {
1169 		if (!rx_path)
1170 			return false;
1171 		if (receive_path > 0 &&
1172 		    (rx_path->hops[0].in_hop_index != receive_path))
1173 			return false;
1174 		if (receive_ring > 0 &&
1175 		    (rx_path->hops[rx_path->path_length - 1].next_hop_index != receive_ring))
1176 			return false;
1177 	}
1178 
1179 	return true;
1180 }
1181 
1182 static int tb_usb3_max_link_rate(struct tb_port *up, struct tb_port *down)
1183 {
1184 	int ret, up_max_rate, down_max_rate;
1185 
1186 	ret = usb4_usb3_port_max_link_rate(up);
1187 	if (ret < 0)
1188 		return ret;
1189 	up_max_rate = ret;
1190 
1191 	ret = usb4_usb3_port_max_link_rate(down);
1192 	if (ret < 0)
1193 		return ret;
1194 	down_max_rate = ret;
1195 
1196 	return min(up_max_rate, down_max_rate);
1197 }
1198 
1199 static int tb_usb3_init(struct tb_tunnel *tunnel)
1200 {
1201 	tb_tunnel_dbg(tunnel, "allocating initial bandwidth %d/%d Mb/s\n",
1202 		      tunnel->allocated_up, tunnel->allocated_down);
1203 
1204 	return usb4_usb3_port_allocate_bandwidth(tunnel->src_port,
1205 						 &tunnel->allocated_up,
1206 						 &tunnel->allocated_down);
1207 }
1208 
1209 static int tb_usb3_activate(struct tb_tunnel *tunnel, bool activate)
1210 {
1211 	int res;
1212 
1213 	res = tb_usb3_port_enable(tunnel->src_port, activate);
1214 	if (res)
1215 		return res;
1216 
1217 	if (tb_port_is_usb3_up(tunnel->dst_port))
1218 		return tb_usb3_port_enable(tunnel->dst_port, activate);
1219 
1220 	return 0;
1221 }
1222 
1223 static int tb_usb3_consumed_bandwidth(struct tb_tunnel *tunnel,
1224 		int *consumed_up, int *consumed_down)
1225 {
1226 	int pcie_enabled = tb_acpi_may_tunnel_pcie();
1227 
1228 	/*
1229 	 * PCIe tunneling, if enabled, affects the USB3 bandwidth so
1230 	 * take that it into account here.
1231 	 */
1232 	*consumed_up = tunnel->allocated_up * (3 + pcie_enabled) / 3;
1233 	*consumed_down = tunnel->allocated_down * (3 + pcie_enabled) / 3;
1234 	return 0;
1235 }
1236 
1237 static int tb_usb3_release_unused_bandwidth(struct tb_tunnel *tunnel)
1238 {
1239 	int ret;
1240 
1241 	ret = usb4_usb3_port_release_bandwidth(tunnel->src_port,
1242 					       &tunnel->allocated_up,
1243 					       &tunnel->allocated_down);
1244 	if (ret)
1245 		return ret;
1246 
1247 	tb_tunnel_dbg(tunnel, "decreased bandwidth allocation to %d/%d Mb/s\n",
1248 		      tunnel->allocated_up, tunnel->allocated_down);
1249 	return 0;
1250 }
1251 
1252 static void tb_usb3_reclaim_available_bandwidth(struct tb_tunnel *tunnel,
1253 						int *available_up,
1254 						int *available_down)
1255 {
1256 	int ret, max_rate, allocate_up, allocate_down;
1257 
1258 	ret = usb4_usb3_port_actual_link_rate(tunnel->src_port);
1259 	if (ret < 0) {
1260 		tb_tunnel_warn(tunnel, "failed to read actual link rate\n");
1261 		return;
1262 	} else if (!ret) {
1263 		/* Use maximum link rate if the link valid is not set */
1264 		ret = usb4_usb3_port_max_link_rate(tunnel->src_port);
1265 		if (ret < 0) {
1266 			tb_tunnel_warn(tunnel, "failed to read maximum link rate\n");
1267 			return;
1268 		}
1269 	}
1270 
1271 	/*
1272 	 * 90% of the max rate can be allocated for isochronous
1273 	 * transfers.
1274 	 */
1275 	max_rate = ret * 90 / 100;
1276 
1277 	/* No need to reclaim if already at maximum */
1278 	if (tunnel->allocated_up >= max_rate &&
1279 	    tunnel->allocated_down >= max_rate)
1280 		return;
1281 
1282 	/* Don't go lower than what is already allocated */
1283 	allocate_up = min(max_rate, *available_up);
1284 	if (allocate_up < tunnel->allocated_up)
1285 		allocate_up = tunnel->allocated_up;
1286 
1287 	allocate_down = min(max_rate, *available_down);
1288 	if (allocate_down < tunnel->allocated_down)
1289 		allocate_down = tunnel->allocated_down;
1290 
1291 	/* If no changes no need to do more */
1292 	if (allocate_up == tunnel->allocated_up &&
1293 	    allocate_down == tunnel->allocated_down)
1294 		return;
1295 
1296 	ret = usb4_usb3_port_allocate_bandwidth(tunnel->src_port, &allocate_up,
1297 						&allocate_down);
1298 	if (ret) {
1299 		tb_tunnel_info(tunnel, "failed to allocate bandwidth\n");
1300 		return;
1301 	}
1302 
1303 	tunnel->allocated_up = allocate_up;
1304 	*available_up -= tunnel->allocated_up;
1305 
1306 	tunnel->allocated_down = allocate_down;
1307 	*available_down -= tunnel->allocated_down;
1308 
1309 	tb_tunnel_dbg(tunnel, "increased bandwidth allocation to %d/%d Mb/s\n",
1310 		      tunnel->allocated_up, tunnel->allocated_down);
1311 }
1312 
1313 static void tb_usb3_init_credits(struct tb_path_hop *hop)
1314 {
1315 	struct tb_port *port = hop->in_port;
1316 	struct tb_switch *sw = port->sw;
1317 	unsigned int credits;
1318 
1319 	if (tb_port_use_credit_allocation(port)) {
1320 		credits = sw->max_usb3_credits;
1321 	} else {
1322 		if (tb_port_is_null(port))
1323 			credits = port->bonded ? 32 : 16;
1324 		else
1325 			credits = 7;
1326 	}
1327 
1328 	hop->initial_credits = credits;
1329 }
1330 
1331 static void tb_usb3_init_path(struct tb_path *path)
1332 {
1333 	struct tb_path_hop *hop;
1334 
1335 	path->egress_fc_enable = TB_PATH_SOURCE | TB_PATH_INTERNAL;
1336 	path->egress_shared_buffer = TB_PATH_NONE;
1337 	path->ingress_fc_enable = TB_PATH_ALL;
1338 	path->ingress_shared_buffer = TB_PATH_NONE;
1339 	path->priority = 3;
1340 	path->weight = 3;
1341 	path->drop_packages = 0;
1342 
1343 	tb_path_for_each_hop(path, hop)
1344 		tb_usb3_init_credits(hop);
1345 }
1346 
1347 /**
1348  * tb_tunnel_discover_usb3() - Discover existing USB3 tunnels
1349  * @tb: Pointer to the domain structure
1350  * @down: USB3 downstream adapter
1351  * @alloc_hopid: Allocate HopIDs from visited ports
1352  *
1353  * If @down adapter is active, follows the tunnel to the USB3 upstream
1354  * adapter and back. Returns the discovered tunnel or %NULL if there was
1355  * no tunnel.
1356  */
1357 struct tb_tunnel *tb_tunnel_discover_usb3(struct tb *tb, struct tb_port *down,
1358 					  bool alloc_hopid)
1359 {
1360 	struct tb_tunnel *tunnel;
1361 	struct tb_path *path;
1362 
1363 	if (!tb_usb3_port_is_enabled(down))
1364 		return NULL;
1365 
1366 	tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_USB3);
1367 	if (!tunnel)
1368 		return NULL;
1369 
1370 	tunnel->activate = tb_usb3_activate;
1371 	tunnel->src_port = down;
1372 
1373 	/*
1374 	 * Discover both paths even if they are not complete. We will
1375 	 * clean them up by calling tb_tunnel_deactivate() below in that
1376 	 * case.
1377 	 */
1378 	path = tb_path_discover(down, TB_USB3_HOPID, NULL, -1,
1379 				&tunnel->dst_port, "USB3 Down", alloc_hopid);
1380 	if (!path) {
1381 		/* Just disable the downstream port */
1382 		tb_usb3_port_enable(down, false);
1383 		goto err_free;
1384 	}
1385 	tunnel->paths[TB_USB3_PATH_DOWN] = path;
1386 	tb_usb3_init_path(tunnel->paths[TB_USB3_PATH_DOWN]);
1387 
1388 	path = tb_path_discover(tunnel->dst_port, -1, down, TB_USB3_HOPID, NULL,
1389 				"USB3 Up", alloc_hopid);
1390 	if (!path)
1391 		goto err_deactivate;
1392 	tunnel->paths[TB_USB3_PATH_UP] = path;
1393 	tb_usb3_init_path(tunnel->paths[TB_USB3_PATH_UP]);
1394 
1395 	/* Validate that the tunnel is complete */
1396 	if (!tb_port_is_usb3_up(tunnel->dst_port)) {
1397 		tb_port_warn(tunnel->dst_port,
1398 			     "path does not end on an USB3 adapter, cleaning up\n");
1399 		goto err_deactivate;
1400 	}
1401 
1402 	if (down != tunnel->src_port) {
1403 		tb_tunnel_warn(tunnel, "path is not complete, cleaning up\n");
1404 		goto err_deactivate;
1405 	}
1406 
1407 	if (!tb_usb3_port_is_enabled(tunnel->dst_port)) {
1408 		tb_tunnel_warn(tunnel,
1409 			       "tunnel is not fully activated, cleaning up\n");
1410 		goto err_deactivate;
1411 	}
1412 
1413 	if (!tb_route(down->sw)) {
1414 		int ret;
1415 
1416 		/*
1417 		 * Read the initial bandwidth allocation for the first
1418 		 * hop tunnel.
1419 		 */
1420 		ret = usb4_usb3_port_allocated_bandwidth(down,
1421 			&tunnel->allocated_up, &tunnel->allocated_down);
1422 		if (ret)
1423 			goto err_deactivate;
1424 
1425 		tb_tunnel_dbg(tunnel, "currently allocated bandwidth %d/%d Mb/s\n",
1426 			      tunnel->allocated_up, tunnel->allocated_down);
1427 
1428 		tunnel->init = tb_usb3_init;
1429 		tunnel->consumed_bandwidth = tb_usb3_consumed_bandwidth;
1430 		tunnel->release_unused_bandwidth =
1431 			tb_usb3_release_unused_bandwidth;
1432 		tunnel->reclaim_available_bandwidth =
1433 			tb_usb3_reclaim_available_bandwidth;
1434 	}
1435 
1436 	tb_tunnel_dbg(tunnel, "discovered\n");
1437 	return tunnel;
1438 
1439 err_deactivate:
1440 	tb_tunnel_deactivate(tunnel);
1441 err_free:
1442 	tb_tunnel_free(tunnel);
1443 
1444 	return NULL;
1445 }
1446 
1447 /**
1448  * tb_tunnel_alloc_usb3() - allocate a USB3 tunnel
1449  * @tb: Pointer to the domain structure
1450  * @up: USB3 upstream adapter port
1451  * @down: USB3 downstream adapter port
1452  * @max_up: Maximum available upstream bandwidth for the USB3 tunnel (%0
1453  *	    if not limited).
1454  * @max_down: Maximum available downstream bandwidth for the USB3 tunnel
1455  *	      (%0 if not limited).
1456  *
1457  * Allocate an USB3 tunnel. The ports must be of type @TB_TYPE_USB3_UP and
1458  * @TB_TYPE_USB3_DOWN.
1459  *
1460  * Return: Returns a tb_tunnel on success or %NULL on failure.
1461  */
1462 struct tb_tunnel *tb_tunnel_alloc_usb3(struct tb *tb, struct tb_port *up,
1463 				       struct tb_port *down, int max_up,
1464 				       int max_down)
1465 {
1466 	struct tb_tunnel *tunnel;
1467 	struct tb_path *path;
1468 	int max_rate = 0;
1469 
1470 	/*
1471 	 * Check that we have enough bandwidth available for the new
1472 	 * USB3 tunnel.
1473 	 */
1474 	if (max_up > 0 || max_down > 0) {
1475 		max_rate = tb_usb3_max_link_rate(down, up);
1476 		if (max_rate < 0)
1477 			return NULL;
1478 
1479 		/* Only 90% can be allocated for USB3 isochronous transfers */
1480 		max_rate = max_rate * 90 / 100;
1481 		tb_port_dbg(up, "required bandwidth for USB3 tunnel %d Mb/s\n",
1482 			    max_rate);
1483 
1484 		if (max_rate > max_up || max_rate > max_down) {
1485 			tb_port_warn(up, "not enough bandwidth for USB3 tunnel\n");
1486 			return NULL;
1487 		}
1488 	}
1489 
1490 	tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_USB3);
1491 	if (!tunnel)
1492 		return NULL;
1493 
1494 	tunnel->activate = tb_usb3_activate;
1495 	tunnel->src_port = down;
1496 	tunnel->dst_port = up;
1497 	tunnel->max_up = max_up;
1498 	tunnel->max_down = max_down;
1499 
1500 	path = tb_path_alloc(tb, down, TB_USB3_HOPID, up, TB_USB3_HOPID, 0,
1501 			     "USB3 Down");
1502 	if (!path) {
1503 		tb_tunnel_free(tunnel);
1504 		return NULL;
1505 	}
1506 	tb_usb3_init_path(path);
1507 	tunnel->paths[TB_USB3_PATH_DOWN] = path;
1508 
1509 	path = tb_path_alloc(tb, up, TB_USB3_HOPID, down, TB_USB3_HOPID, 0,
1510 			     "USB3 Up");
1511 	if (!path) {
1512 		tb_tunnel_free(tunnel);
1513 		return NULL;
1514 	}
1515 	tb_usb3_init_path(path);
1516 	tunnel->paths[TB_USB3_PATH_UP] = path;
1517 
1518 	if (!tb_route(down->sw)) {
1519 		tunnel->allocated_up = max_rate;
1520 		tunnel->allocated_down = max_rate;
1521 
1522 		tunnel->init = tb_usb3_init;
1523 		tunnel->consumed_bandwidth = tb_usb3_consumed_bandwidth;
1524 		tunnel->release_unused_bandwidth =
1525 			tb_usb3_release_unused_bandwidth;
1526 		tunnel->reclaim_available_bandwidth =
1527 			tb_usb3_reclaim_available_bandwidth;
1528 	}
1529 
1530 	return tunnel;
1531 }
1532 
1533 /**
1534  * tb_tunnel_free() - free a tunnel
1535  * @tunnel: Tunnel to be freed
1536  *
1537  * Frees a tunnel. The tunnel does not need to be deactivated.
1538  */
1539 void tb_tunnel_free(struct tb_tunnel *tunnel)
1540 {
1541 	int i;
1542 
1543 	if (!tunnel)
1544 		return;
1545 
1546 	if (tunnel->deinit)
1547 		tunnel->deinit(tunnel);
1548 
1549 	for (i = 0; i < tunnel->npaths; i++) {
1550 		if (tunnel->paths[i])
1551 			tb_path_free(tunnel->paths[i]);
1552 	}
1553 
1554 	kfree(tunnel->paths);
1555 	kfree(tunnel);
1556 }
1557 
1558 /**
1559  * tb_tunnel_is_invalid - check whether an activated path is still valid
1560  * @tunnel: Tunnel to check
1561  */
1562 bool tb_tunnel_is_invalid(struct tb_tunnel *tunnel)
1563 {
1564 	int i;
1565 
1566 	for (i = 0; i < tunnel->npaths; i++) {
1567 		WARN_ON(!tunnel->paths[i]->activated);
1568 		if (tb_path_is_invalid(tunnel->paths[i]))
1569 			return true;
1570 	}
1571 
1572 	return false;
1573 }
1574 
1575 /**
1576  * tb_tunnel_restart() - activate a tunnel after a hardware reset
1577  * @tunnel: Tunnel to restart
1578  *
1579  * Return: 0 on success and negative errno in case if failure
1580  */
1581 int tb_tunnel_restart(struct tb_tunnel *tunnel)
1582 {
1583 	int res, i;
1584 
1585 	tb_tunnel_dbg(tunnel, "activating\n");
1586 
1587 	/*
1588 	 * Make sure all paths are properly disabled before enabling
1589 	 * them again.
1590 	 */
1591 	for (i = 0; i < tunnel->npaths; i++) {
1592 		if (tunnel->paths[i]->activated) {
1593 			tb_path_deactivate(tunnel->paths[i]);
1594 			tunnel->paths[i]->activated = false;
1595 		}
1596 	}
1597 
1598 	if (tunnel->init) {
1599 		res = tunnel->init(tunnel);
1600 		if (res)
1601 			return res;
1602 	}
1603 
1604 	for (i = 0; i < tunnel->npaths; i++) {
1605 		res = tb_path_activate(tunnel->paths[i]);
1606 		if (res)
1607 			goto err;
1608 	}
1609 
1610 	if (tunnel->activate) {
1611 		res = tunnel->activate(tunnel, true);
1612 		if (res)
1613 			goto err;
1614 	}
1615 
1616 	return 0;
1617 
1618 err:
1619 	tb_tunnel_warn(tunnel, "activation failed\n");
1620 	tb_tunnel_deactivate(tunnel);
1621 	return res;
1622 }
1623 
1624 /**
1625  * tb_tunnel_activate() - activate a tunnel
1626  * @tunnel: Tunnel to activate
1627  *
1628  * Return: Returns 0 on success or an error code on failure.
1629  */
1630 int tb_tunnel_activate(struct tb_tunnel *tunnel)
1631 {
1632 	int i;
1633 
1634 	for (i = 0; i < tunnel->npaths; i++) {
1635 		if (tunnel->paths[i]->activated) {
1636 			tb_tunnel_WARN(tunnel,
1637 				       "trying to activate an already activated tunnel\n");
1638 			return -EINVAL;
1639 		}
1640 	}
1641 
1642 	return tb_tunnel_restart(tunnel);
1643 }
1644 
1645 /**
1646  * tb_tunnel_deactivate() - deactivate a tunnel
1647  * @tunnel: Tunnel to deactivate
1648  */
1649 void tb_tunnel_deactivate(struct tb_tunnel *tunnel)
1650 {
1651 	int i;
1652 
1653 	tb_tunnel_dbg(tunnel, "deactivating\n");
1654 
1655 	if (tunnel->activate)
1656 		tunnel->activate(tunnel, false);
1657 
1658 	for (i = 0; i < tunnel->npaths; i++) {
1659 		if (tunnel->paths[i] && tunnel->paths[i]->activated)
1660 			tb_path_deactivate(tunnel->paths[i]);
1661 	}
1662 }
1663 
1664 /**
1665  * tb_tunnel_port_on_path() - Does the tunnel go through port
1666  * @tunnel: Tunnel to check
1667  * @port: Port to check
1668  *
1669  * Returns true if @tunnel goes through @port (direction does not matter),
1670  * false otherwise.
1671  */
1672 bool tb_tunnel_port_on_path(const struct tb_tunnel *tunnel,
1673 			    const struct tb_port *port)
1674 {
1675 	int i;
1676 
1677 	for (i = 0; i < tunnel->npaths; i++) {
1678 		if (!tunnel->paths[i])
1679 			continue;
1680 
1681 		if (tb_path_port_on_path(tunnel->paths[i], port))
1682 			return true;
1683 	}
1684 
1685 	return false;
1686 }
1687 
1688 static bool tb_tunnel_is_active(const struct tb_tunnel *tunnel)
1689 {
1690 	int i;
1691 
1692 	for (i = 0; i < tunnel->npaths; i++) {
1693 		if (!tunnel->paths[i])
1694 			return false;
1695 		if (!tunnel->paths[i]->activated)
1696 			return false;
1697 	}
1698 
1699 	return true;
1700 }
1701 
1702 /**
1703  * tb_tunnel_consumed_bandwidth() - Return bandwidth consumed by the tunnel
1704  * @tunnel: Tunnel to check
1705  * @consumed_up: Consumed bandwidth in Mb/s from @dst_port to @src_port.
1706  *		 Can be %NULL.
1707  * @consumed_down: Consumed bandwidth in Mb/s from @src_port to @dst_port.
1708  *		   Can be %NULL.
1709  *
1710  * Stores the amount of isochronous bandwidth @tunnel consumes in
1711  * @consumed_up and @consumed_down. In case of success returns %0,
1712  * negative errno otherwise.
1713  */
1714 int tb_tunnel_consumed_bandwidth(struct tb_tunnel *tunnel, int *consumed_up,
1715 				 int *consumed_down)
1716 {
1717 	int up_bw = 0, down_bw = 0;
1718 
1719 	if (!tb_tunnel_is_active(tunnel))
1720 		goto out;
1721 
1722 	if (tunnel->consumed_bandwidth) {
1723 		int ret;
1724 
1725 		ret = tunnel->consumed_bandwidth(tunnel, &up_bw, &down_bw);
1726 		if (ret)
1727 			return ret;
1728 
1729 		tb_tunnel_dbg(tunnel, "consumed bandwidth %d/%d Mb/s\n", up_bw,
1730 			      down_bw);
1731 	}
1732 
1733 out:
1734 	if (consumed_up)
1735 		*consumed_up = up_bw;
1736 	if (consumed_down)
1737 		*consumed_down = down_bw;
1738 
1739 	return 0;
1740 }
1741 
1742 /**
1743  * tb_tunnel_release_unused_bandwidth() - Release unused bandwidth
1744  * @tunnel: Tunnel whose unused bandwidth to release
1745  *
1746  * If tunnel supports dynamic bandwidth management (USB3 tunnels at the
1747  * moment) this function makes it to release all the unused bandwidth.
1748  *
1749  * Returns %0 in case of success and negative errno otherwise.
1750  */
1751 int tb_tunnel_release_unused_bandwidth(struct tb_tunnel *tunnel)
1752 {
1753 	if (!tb_tunnel_is_active(tunnel))
1754 		return 0;
1755 
1756 	if (tunnel->release_unused_bandwidth) {
1757 		int ret;
1758 
1759 		ret = tunnel->release_unused_bandwidth(tunnel);
1760 		if (ret)
1761 			return ret;
1762 	}
1763 
1764 	return 0;
1765 }
1766 
1767 /**
1768  * tb_tunnel_reclaim_available_bandwidth() - Reclaim available bandwidth
1769  * @tunnel: Tunnel reclaiming available bandwidth
1770  * @available_up: Available upstream bandwidth (in Mb/s)
1771  * @available_down: Available downstream bandwidth (in Mb/s)
1772  *
1773  * Reclaims bandwidth from @available_up and @available_down and updates
1774  * the variables accordingly (e.g decreases both according to what was
1775  * reclaimed by the tunnel). If nothing was reclaimed the values are
1776  * kept as is.
1777  */
1778 void tb_tunnel_reclaim_available_bandwidth(struct tb_tunnel *tunnel,
1779 					   int *available_up,
1780 					   int *available_down)
1781 {
1782 	if (!tb_tunnel_is_active(tunnel))
1783 		return;
1784 
1785 	if (tunnel->reclaim_available_bandwidth)
1786 		tunnel->reclaim_available_bandwidth(tunnel, available_up,
1787 						    available_down);
1788 }
1789