xref: /openbmc/linux/drivers/thunderbolt/tmu.c (revision 2fa5ebe3)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Thunderbolt Time Management Unit (TMU) support
4  *
5  * Copyright (C) 2019, Intel Corporation
6  * Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
7  *	    Rajmohan Mani <rajmohan.mani@intel.com>
8  */
9 
10 #include <linux/delay.h>
11 
12 #include "tb.h"
13 
14 static int tb_switch_set_tmu_mode_params(struct tb_switch *sw,
15 					 enum tb_switch_tmu_rate rate)
16 {
17 	u32 freq_meas_wind[2] = { 30, 800 };
18 	u32 avg_const[2] = { 4, 8 };
19 	u32 freq, avg, val;
20 	int ret;
21 
22 	if (rate == TB_SWITCH_TMU_RATE_NORMAL) {
23 		freq = freq_meas_wind[0];
24 		avg = avg_const[0];
25 	} else if (rate == TB_SWITCH_TMU_RATE_HIFI) {
26 		freq = freq_meas_wind[1];
27 		avg = avg_const[1];
28 	} else {
29 		return 0;
30 	}
31 
32 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
33 			 sw->tmu.cap + TMU_RTR_CS_0, 1);
34 	if (ret)
35 		return ret;
36 
37 	val &= ~TMU_RTR_CS_0_FREQ_WIND_MASK;
38 	val |= FIELD_PREP(TMU_RTR_CS_0_FREQ_WIND_MASK, freq);
39 
40 	ret = tb_sw_write(sw, &val, TB_CFG_SWITCH,
41 			  sw->tmu.cap + TMU_RTR_CS_0, 1);
42 	if (ret)
43 		return ret;
44 
45 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
46 			 sw->tmu.cap + TMU_RTR_CS_15, 1);
47 	if (ret)
48 		return ret;
49 
50 	val &= ~TMU_RTR_CS_15_FREQ_AVG_MASK &
51 		~TMU_RTR_CS_15_DELAY_AVG_MASK &
52 		~TMU_RTR_CS_15_OFFSET_AVG_MASK &
53 		~TMU_RTR_CS_15_ERROR_AVG_MASK;
54 	val |=  FIELD_PREP(TMU_RTR_CS_15_FREQ_AVG_MASK, avg) |
55 		FIELD_PREP(TMU_RTR_CS_15_DELAY_AVG_MASK, avg) |
56 		FIELD_PREP(TMU_RTR_CS_15_OFFSET_AVG_MASK, avg) |
57 		FIELD_PREP(TMU_RTR_CS_15_ERROR_AVG_MASK, avg);
58 
59 	return tb_sw_write(sw, &val, TB_CFG_SWITCH,
60 			   sw->tmu.cap + TMU_RTR_CS_15, 1);
61 }
62 
63 static const char *tb_switch_tmu_mode_name(const struct tb_switch *sw)
64 {
65 	bool root_switch = !tb_route(sw);
66 
67 	switch (sw->tmu.rate) {
68 	case TB_SWITCH_TMU_RATE_OFF:
69 		return "off";
70 
71 	case TB_SWITCH_TMU_RATE_HIFI:
72 		/* Root switch does not have upstream directionality */
73 		if (root_switch)
74 			return "HiFi";
75 		if (sw->tmu.unidirectional)
76 			return "uni-directional, HiFi";
77 		return "bi-directional, HiFi";
78 
79 	case TB_SWITCH_TMU_RATE_NORMAL:
80 		if (root_switch)
81 			return "normal";
82 		return "uni-directional, normal";
83 
84 	default:
85 		return "unknown";
86 	}
87 }
88 
89 static bool tb_switch_tmu_ucap_supported(struct tb_switch *sw)
90 {
91 	int ret;
92 	u32 val;
93 
94 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
95 			 sw->tmu.cap + TMU_RTR_CS_0, 1);
96 	if (ret)
97 		return false;
98 
99 	return !!(val & TMU_RTR_CS_0_UCAP);
100 }
101 
102 static int tb_switch_tmu_rate_read(struct tb_switch *sw)
103 {
104 	int ret;
105 	u32 val;
106 
107 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
108 			 sw->tmu.cap + TMU_RTR_CS_3, 1);
109 	if (ret)
110 		return ret;
111 
112 	val >>= TMU_RTR_CS_3_TS_PACKET_INTERVAL_SHIFT;
113 	return val;
114 }
115 
116 static int tb_switch_tmu_rate_write(struct tb_switch *sw, int rate)
117 {
118 	int ret;
119 	u32 val;
120 
121 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
122 			 sw->tmu.cap + TMU_RTR_CS_3, 1);
123 	if (ret)
124 		return ret;
125 
126 	val &= ~TMU_RTR_CS_3_TS_PACKET_INTERVAL_MASK;
127 	val |= rate << TMU_RTR_CS_3_TS_PACKET_INTERVAL_SHIFT;
128 
129 	return tb_sw_write(sw, &val, TB_CFG_SWITCH,
130 			   sw->tmu.cap + TMU_RTR_CS_3, 1);
131 }
132 
133 static int tb_port_tmu_write(struct tb_port *port, u8 offset, u32 mask,
134 			     u32 value)
135 {
136 	u32 data;
137 	int ret;
138 
139 	ret = tb_port_read(port, &data, TB_CFG_PORT, port->cap_tmu + offset, 1);
140 	if (ret)
141 		return ret;
142 
143 	data &= ~mask;
144 	data |= value;
145 
146 	return tb_port_write(port, &data, TB_CFG_PORT,
147 			     port->cap_tmu + offset, 1);
148 }
149 
150 static int tb_port_tmu_set_unidirectional(struct tb_port *port,
151 					  bool unidirectional)
152 {
153 	u32 val;
154 
155 	if (!port->sw->tmu.has_ucap)
156 		return 0;
157 
158 	val = unidirectional ? TMU_ADP_CS_3_UDM : 0;
159 	return tb_port_tmu_write(port, TMU_ADP_CS_3, TMU_ADP_CS_3_UDM, val);
160 }
161 
162 static inline int tb_port_tmu_unidirectional_disable(struct tb_port *port)
163 {
164 	return tb_port_tmu_set_unidirectional(port, false);
165 }
166 
167 static inline int tb_port_tmu_unidirectional_enable(struct tb_port *port)
168 {
169 	return tb_port_tmu_set_unidirectional(port, true);
170 }
171 
172 static bool tb_port_tmu_is_unidirectional(struct tb_port *port)
173 {
174 	int ret;
175 	u32 val;
176 
177 	ret = tb_port_read(port, &val, TB_CFG_PORT,
178 			   port->cap_tmu + TMU_ADP_CS_3, 1);
179 	if (ret)
180 		return false;
181 
182 	return val & TMU_ADP_CS_3_UDM;
183 }
184 
185 static int tb_port_tmu_time_sync(struct tb_port *port, bool time_sync)
186 {
187 	u32 val = time_sync ? TMU_ADP_CS_6_DTS : 0;
188 
189 	return tb_port_tmu_write(port, TMU_ADP_CS_6, TMU_ADP_CS_6_DTS, val);
190 }
191 
192 static int tb_port_tmu_time_sync_disable(struct tb_port *port)
193 {
194 	return tb_port_tmu_time_sync(port, true);
195 }
196 
197 static int tb_port_tmu_time_sync_enable(struct tb_port *port)
198 {
199 	return tb_port_tmu_time_sync(port, false);
200 }
201 
202 static int tb_switch_tmu_set_time_disruption(struct tb_switch *sw, bool set)
203 {
204 	u32 val, offset, bit;
205 	int ret;
206 
207 	if (tb_switch_is_usb4(sw)) {
208 		offset = sw->tmu.cap + TMU_RTR_CS_0;
209 		bit = TMU_RTR_CS_0_TD;
210 	} else {
211 		offset = sw->cap_vsec_tmu + TB_TIME_VSEC_3_CS_26;
212 		bit = TB_TIME_VSEC_3_CS_26_TD;
213 	}
214 
215 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, offset, 1);
216 	if (ret)
217 		return ret;
218 
219 	if (set)
220 		val |= bit;
221 	else
222 		val &= ~bit;
223 
224 	return tb_sw_write(sw, &val, TB_CFG_SWITCH, offset, 1);
225 }
226 
227 /**
228  * tb_switch_tmu_init() - Initialize switch TMU structures
229  * @sw: Switch to initialized
230  *
231  * This function must be called before other TMU related functions to
232  * makes the internal structures are filled in correctly. Does not
233  * change any hardware configuration.
234  */
235 int tb_switch_tmu_init(struct tb_switch *sw)
236 {
237 	struct tb_port *port;
238 	int ret;
239 
240 	if (tb_switch_is_icm(sw))
241 		return 0;
242 
243 	ret = tb_switch_find_cap(sw, TB_SWITCH_CAP_TMU);
244 	if (ret > 0)
245 		sw->tmu.cap = ret;
246 
247 	tb_switch_for_each_port(sw, port) {
248 		int cap;
249 
250 		cap = tb_port_find_cap(port, TB_PORT_CAP_TIME1);
251 		if (cap > 0)
252 			port->cap_tmu = cap;
253 	}
254 
255 	ret = tb_switch_tmu_rate_read(sw);
256 	if (ret < 0)
257 		return ret;
258 
259 	sw->tmu.rate = ret;
260 
261 	sw->tmu.has_ucap = tb_switch_tmu_ucap_supported(sw);
262 	if (sw->tmu.has_ucap) {
263 		tb_sw_dbg(sw, "TMU: supports uni-directional mode\n");
264 
265 		if (tb_route(sw)) {
266 			struct tb_port *up = tb_upstream_port(sw);
267 
268 			sw->tmu.unidirectional =
269 				tb_port_tmu_is_unidirectional(up);
270 		}
271 	} else {
272 		sw->tmu.unidirectional = false;
273 	}
274 
275 	tb_sw_dbg(sw, "TMU: current mode: %s\n", tb_switch_tmu_mode_name(sw));
276 	return 0;
277 }
278 
279 /**
280  * tb_switch_tmu_post_time() - Update switch local time
281  * @sw: Switch whose time to update
282  *
283  * Updates switch local time using time posting procedure.
284  */
285 int tb_switch_tmu_post_time(struct tb_switch *sw)
286 {
287 	unsigned int post_time_high_offset, post_time_high = 0;
288 	unsigned int post_local_time_offset, post_time_offset;
289 	struct tb_switch *root_switch = sw->tb->root_switch;
290 	u64 hi, mid, lo, local_time, post_time;
291 	int i, ret, retries = 100;
292 	u32 gm_local_time[3];
293 
294 	if (!tb_route(sw))
295 		return 0;
296 
297 	if (!tb_switch_is_usb4(sw))
298 		return 0;
299 
300 	/* Need to be able to read the grand master time */
301 	if (!root_switch->tmu.cap)
302 		return 0;
303 
304 	ret = tb_sw_read(root_switch, gm_local_time, TB_CFG_SWITCH,
305 			 root_switch->tmu.cap + TMU_RTR_CS_1,
306 			 ARRAY_SIZE(gm_local_time));
307 	if (ret)
308 		return ret;
309 
310 	for (i = 0; i < ARRAY_SIZE(gm_local_time); i++)
311 		tb_sw_dbg(root_switch, "local_time[%d]=0x%08x\n", i,
312 			  gm_local_time[i]);
313 
314 	/* Convert to nanoseconds (drop fractional part) */
315 	hi = gm_local_time[2] & TMU_RTR_CS_3_LOCAL_TIME_NS_MASK;
316 	mid = gm_local_time[1];
317 	lo = (gm_local_time[0] & TMU_RTR_CS_1_LOCAL_TIME_NS_MASK) >>
318 		TMU_RTR_CS_1_LOCAL_TIME_NS_SHIFT;
319 	local_time = hi << 48 | mid << 16 | lo;
320 
321 	/* Tell the switch that time sync is disrupted for a while */
322 	ret = tb_switch_tmu_set_time_disruption(sw, true);
323 	if (ret)
324 		return ret;
325 
326 	post_local_time_offset = sw->tmu.cap + TMU_RTR_CS_22;
327 	post_time_offset = sw->tmu.cap + TMU_RTR_CS_24;
328 	post_time_high_offset = sw->tmu.cap + TMU_RTR_CS_25;
329 
330 	/*
331 	 * Write the Grandmaster time to the Post Local Time registers
332 	 * of the new switch.
333 	 */
334 	ret = tb_sw_write(sw, &local_time, TB_CFG_SWITCH,
335 			  post_local_time_offset, 2);
336 	if (ret)
337 		goto out;
338 
339 	/*
340 	 * Have the new switch update its local time by:
341 	 * 1) writing 0x1 to the Post Time Low register and 0xffffffff to
342 	 * Post Time High register.
343 	 * 2) write 0 to Post Time High register and then wait for
344 	 * the completion of the post_time register becomes 0.
345 	 * This means the time has been converged properly.
346 	 */
347 	post_time = 0xffffffff00000001ULL;
348 
349 	ret = tb_sw_write(sw, &post_time, TB_CFG_SWITCH, post_time_offset, 2);
350 	if (ret)
351 		goto out;
352 
353 	ret = tb_sw_write(sw, &post_time_high, TB_CFG_SWITCH,
354 			  post_time_high_offset, 1);
355 	if (ret)
356 		goto out;
357 
358 	do {
359 		usleep_range(5, 10);
360 		ret = tb_sw_read(sw, &post_time, TB_CFG_SWITCH,
361 				 post_time_offset, 2);
362 		if (ret)
363 			goto out;
364 	} while (--retries && post_time);
365 
366 	if (!retries) {
367 		ret = -ETIMEDOUT;
368 		goto out;
369 	}
370 
371 	tb_sw_dbg(sw, "TMU: updated local time to %#llx\n", local_time);
372 
373 out:
374 	tb_switch_tmu_set_time_disruption(sw, false);
375 	return ret;
376 }
377 
378 /**
379  * tb_switch_tmu_disable() - Disable TMU of a switch
380  * @sw: Switch whose TMU to disable
381  *
382  * Turns off TMU of @sw if it is enabled. If not enabled does nothing.
383  */
384 int tb_switch_tmu_disable(struct tb_switch *sw)
385 {
386 	/*
387 	 * No need to disable TMU on devices that don't support CLx since
388 	 * on these devices e.g. Alpine Ridge and earlier, the TMU mode
389 	 * HiFi bi-directional is enabled by default and we don't change it.
390 	 */
391 	if (!tb_switch_is_clx_supported(sw))
392 		return 0;
393 
394 	/* Already disabled? */
395 	if (sw->tmu.rate == TB_SWITCH_TMU_RATE_OFF)
396 		return 0;
397 
398 
399 	if (tb_route(sw)) {
400 		bool unidirectional = sw->tmu.unidirectional;
401 		struct tb_switch *parent = tb_switch_parent(sw);
402 		struct tb_port *down, *up;
403 		int ret;
404 
405 		down = tb_port_at(tb_route(sw), parent);
406 		up = tb_upstream_port(sw);
407 		/*
408 		 * In case of uni-directional time sync, TMU handshake is
409 		 * initiated by upstream router. In case of bi-directional
410 		 * time sync, TMU handshake is initiated by downstream router.
411 		 * We change downstream router's rate to off for both uni/bidir
412 		 * cases although it is needed only for the bi-directional mode.
413 		 * We avoid changing upstream router's mode since it might
414 		 * have another downstream router plugged, that is set to
415 		 * uni-directional mode and we don't want to change it's TMU
416 		 * mode.
417 		 */
418 		tb_switch_tmu_rate_write(sw, TB_SWITCH_TMU_RATE_OFF);
419 
420 		tb_port_tmu_time_sync_disable(up);
421 		ret = tb_port_tmu_time_sync_disable(down);
422 		if (ret)
423 			return ret;
424 
425 		if (unidirectional) {
426 			/* The switch may be unplugged so ignore any errors */
427 			tb_port_tmu_unidirectional_disable(up);
428 			ret = tb_port_tmu_unidirectional_disable(down);
429 			if (ret)
430 				return ret;
431 		}
432 	} else {
433 		tb_switch_tmu_rate_write(sw, TB_SWITCH_TMU_RATE_OFF);
434 	}
435 
436 	sw->tmu.unidirectional = false;
437 	sw->tmu.rate = TB_SWITCH_TMU_RATE_OFF;
438 
439 	tb_sw_dbg(sw, "TMU: disabled\n");
440 	return 0;
441 }
442 
443 static void __tb_switch_tmu_off(struct tb_switch *sw, bool unidirectional)
444 {
445 	struct tb_switch *parent = tb_switch_parent(sw);
446 	struct tb_port *down, *up;
447 
448 	down = tb_port_at(tb_route(sw), parent);
449 	up = tb_upstream_port(sw);
450 	/*
451 	 * In case of any failure in one of the steps when setting
452 	 * bi-directional or uni-directional TMU mode, get back to the TMU
453 	 * configurations in off mode. In case of additional failures in
454 	 * the functions below, ignore them since the caller shall already
455 	 * report a failure.
456 	 */
457 	tb_port_tmu_time_sync_disable(down);
458 	tb_port_tmu_time_sync_disable(up);
459 	if (unidirectional)
460 		tb_switch_tmu_rate_write(parent, TB_SWITCH_TMU_RATE_OFF);
461 	else
462 		tb_switch_tmu_rate_write(sw, TB_SWITCH_TMU_RATE_OFF);
463 
464 	tb_switch_set_tmu_mode_params(sw, sw->tmu.rate);
465 	tb_port_tmu_unidirectional_disable(down);
466 	tb_port_tmu_unidirectional_disable(up);
467 }
468 
469 /*
470  * This function is called when the previous TMU mode was
471  * TB_SWITCH_TMU_RATE_OFF.
472  */
473 static int __tb_switch_tmu_enable_bidirectional(struct tb_switch *sw)
474 {
475 	struct tb_switch *parent = tb_switch_parent(sw);
476 	struct tb_port *up, *down;
477 	int ret;
478 
479 	up = tb_upstream_port(sw);
480 	down = tb_port_at(tb_route(sw), parent);
481 
482 	ret = tb_port_tmu_unidirectional_disable(up);
483 	if (ret)
484 		return ret;
485 
486 	ret = tb_port_tmu_unidirectional_disable(down);
487 	if (ret)
488 		goto out;
489 
490 	ret = tb_switch_tmu_rate_write(sw, TB_SWITCH_TMU_RATE_HIFI);
491 	if (ret)
492 		goto out;
493 
494 	ret = tb_port_tmu_time_sync_enable(up);
495 	if (ret)
496 		goto out;
497 
498 	ret = tb_port_tmu_time_sync_enable(down);
499 	if (ret)
500 		goto out;
501 
502 	return 0;
503 
504 out:
505 	__tb_switch_tmu_off(sw, false);
506 	return ret;
507 }
508 
509 static int tb_switch_tmu_objection_mask(struct tb_switch *sw)
510 {
511 	u32 val;
512 	int ret;
513 
514 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
515 			 sw->cap_vsec_tmu + TB_TIME_VSEC_3_CS_9, 1);
516 	if (ret)
517 		return ret;
518 
519 	val &= ~TB_TIME_VSEC_3_CS_9_TMU_OBJ_MASK;
520 
521 	return tb_sw_write(sw, &val, TB_CFG_SWITCH,
522 			   sw->cap_vsec_tmu + TB_TIME_VSEC_3_CS_9, 1);
523 }
524 
525 static int tb_switch_tmu_unidirectional_enable(struct tb_switch *sw)
526 {
527 	struct tb_port *up = tb_upstream_port(sw);
528 
529 	return tb_port_tmu_write(up, TMU_ADP_CS_6,
530 				 TMU_ADP_CS_6_DISABLE_TMU_OBJ_MASK,
531 				 TMU_ADP_CS_6_DISABLE_TMU_OBJ_MASK);
532 }
533 
534 /*
535  * This function is called when the previous TMU mode was
536  * TB_SWITCH_TMU_RATE_OFF.
537  */
538 static int __tb_switch_tmu_enable_unidirectional(struct tb_switch *sw)
539 {
540 	struct tb_switch *parent = tb_switch_parent(sw);
541 	struct tb_port *up, *down;
542 	int ret;
543 
544 	up = tb_upstream_port(sw);
545 	down = tb_port_at(tb_route(sw), parent);
546 	ret = tb_switch_tmu_rate_write(parent, sw->tmu.rate_request);
547 	if (ret)
548 		return ret;
549 
550 	ret = tb_switch_set_tmu_mode_params(sw, sw->tmu.rate_request);
551 	if (ret)
552 		return ret;
553 
554 	ret = tb_port_tmu_unidirectional_enable(up);
555 	if (ret)
556 		goto out;
557 
558 	ret = tb_port_tmu_time_sync_enable(up);
559 	if (ret)
560 		goto out;
561 
562 	ret = tb_port_tmu_unidirectional_enable(down);
563 	if (ret)
564 		goto out;
565 
566 	ret = tb_port_tmu_time_sync_enable(down);
567 	if (ret)
568 		goto out;
569 
570 	return 0;
571 
572 out:
573 	__tb_switch_tmu_off(sw, true);
574 	return ret;
575 }
576 
577 static void __tb_switch_tmu_change_mode_prev(struct tb_switch *sw)
578 {
579 	struct tb_switch *parent = tb_switch_parent(sw);
580 	struct tb_port *down, *up;
581 
582 	down = tb_port_at(tb_route(sw), parent);
583 	up = tb_upstream_port(sw);
584 	/*
585 	 * In case of any failure in one of the steps when change mode,
586 	 * get back to the TMU configurations in previous mode.
587 	 * In case of additional failures in the functions below,
588 	 * ignore them since the caller shall already report a failure.
589 	 */
590 	tb_port_tmu_set_unidirectional(down, sw->tmu.unidirectional);
591 	if (sw->tmu.unidirectional_request)
592 		tb_switch_tmu_rate_write(parent, sw->tmu.rate);
593 	else
594 		tb_switch_tmu_rate_write(sw, sw->tmu.rate);
595 
596 	tb_switch_set_tmu_mode_params(sw, sw->tmu.rate);
597 	tb_port_tmu_set_unidirectional(up, sw->tmu.unidirectional);
598 }
599 
600 static int __tb_switch_tmu_change_mode(struct tb_switch *sw)
601 {
602 	struct tb_switch *parent = tb_switch_parent(sw);
603 	struct tb_port *up, *down;
604 	int ret;
605 
606 	up = tb_upstream_port(sw);
607 	down = tb_port_at(tb_route(sw), parent);
608 	ret = tb_port_tmu_set_unidirectional(down, sw->tmu.unidirectional_request);
609 	if (ret)
610 		goto out;
611 
612 	if (sw->tmu.unidirectional_request)
613 		ret = tb_switch_tmu_rate_write(parent, sw->tmu.rate_request);
614 	else
615 		ret = tb_switch_tmu_rate_write(sw, sw->tmu.rate_request);
616 	if (ret)
617 		return ret;
618 
619 	ret = tb_switch_set_tmu_mode_params(sw, sw->tmu.rate_request);
620 	if (ret)
621 		return ret;
622 
623 	ret = tb_port_tmu_set_unidirectional(up, sw->tmu.unidirectional_request);
624 	if (ret)
625 		goto out;
626 
627 	ret = tb_port_tmu_time_sync_enable(down);
628 	if (ret)
629 		goto out;
630 
631 	ret = tb_port_tmu_time_sync_enable(up);
632 	if (ret)
633 		goto out;
634 
635 	return 0;
636 
637 out:
638 	__tb_switch_tmu_change_mode_prev(sw);
639 	return ret;
640 }
641 
642 /**
643  * tb_switch_tmu_enable() - Enable TMU on a router
644  * @sw: Router whose TMU to enable
645  *
646  * Enables TMU of a router to be in uni-directional Normal/HiFi
647  * or bi-directional HiFi mode. Calling tb_switch_tmu_configure() is required
648  * before calling this function, to select the mode Normal/HiFi and
649  * directionality (uni-directional/bi-directional).
650  * In HiFi mode all tunneling should work. In Normal mode, DP tunneling can't
651  * work. Uni-directional mode is required for CLx (Link Low-Power) to work.
652  */
653 int tb_switch_tmu_enable(struct tb_switch *sw)
654 {
655 	bool unidirectional = sw->tmu.unidirectional_request;
656 	int ret;
657 
658 	if (unidirectional && !sw->tmu.has_ucap)
659 		return -EOPNOTSUPP;
660 
661 	/*
662 	 * No need to enable TMU on devices that don't support CLx since on
663 	 * these devices e.g. Alpine Ridge and earlier, the TMU mode HiFi
664 	 * bi-directional is enabled by default.
665 	 */
666 	if (!tb_switch_is_clx_supported(sw))
667 		return 0;
668 
669 	if (tb_switch_tmu_is_enabled(sw, sw->tmu.unidirectional_request))
670 		return 0;
671 
672 	if (tb_switch_is_titan_ridge(sw) && unidirectional) {
673 		/*
674 		 * Titan Ridge supports CL0s and CL1 only. CL0s and CL1 are
675 		 * enabled and supported together.
676 		 */
677 		if (!tb_switch_is_clx_enabled(sw, TB_CL1))
678 			return -EOPNOTSUPP;
679 
680 		ret = tb_switch_tmu_objection_mask(sw);
681 		if (ret)
682 			return ret;
683 
684 		ret = tb_switch_tmu_unidirectional_enable(sw);
685 		if (ret)
686 			return ret;
687 	}
688 
689 	ret = tb_switch_tmu_set_time_disruption(sw, true);
690 	if (ret)
691 		return ret;
692 
693 	if (tb_route(sw)) {
694 		/*
695 		 * The used mode changes are from OFF to
696 		 * HiFi-Uni/HiFi-BiDir/Normal-Uni or from Normal-Uni to
697 		 * HiFi-Uni.
698 		 */
699 		if (sw->tmu.rate == TB_SWITCH_TMU_RATE_OFF) {
700 			if (unidirectional)
701 				ret = __tb_switch_tmu_enable_unidirectional(sw);
702 			else
703 				ret = __tb_switch_tmu_enable_bidirectional(sw);
704 			if (ret)
705 				return ret;
706 		} else if (sw->tmu.rate == TB_SWITCH_TMU_RATE_NORMAL) {
707 			ret = __tb_switch_tmu_change_mode(sw);
708 			if (ret)
709 				return ret;
710 		}
711 		sw->tmu.unidirectional = unidirectional;
712 	} else {
713 		/*
714 		 * Host router port configurations are written as
715 		 * part of configurations for downstream port of the parent
716 		 * of the child node - see above.
717 		 * Here only the host router' rate configuration is written.
718 		 */
719 		ret = tb_switch_tmu_rate_write(sw, sw->tmu.rate_request);
720 		if (ret)
721 			return ret;
722 	}
723 
724 	sw->tmu.rate = sw->tmu.rate_request;
725 
726 	tb_sw_dbg(sw, "TMU: mode set to: %s\n", tb_switch_tmu_mode_name(sw));
727 	return tb_switch_tmu_set_time_disruption(sw, false);
728 }
729 
730 /**
731  * tb_switch_tmu_configure() - Configure the TMU rate and directionality
732  * @sw: Router whose mode to change
733  * @rate: Rate to configure Off/Normal/HiFi
734  * @unidirectional: If uni-directional (bi-directional otherwise)
735  *
736  * Selects the rate of the TMU and directionality (uni-directional or
737  * bi-directional). Must be called before tb_switch_tmu_enable().
738  */
739 void tb_switch_tmu_configure(struct tb_switch *sw,
740 			     enum tb_switch_tmu_rate rate, bool unidirectional)
741 {
742 	sw->tmu.unidirectional_request = unidirectional;
743 	sw->tmu.rate_request = rate;
744 }
745 
746 static int tb_switch_tmu_config_enable(struct device *dev, void *rate)
747 {
748 	if (tb_is_switch(dev)) {
749 		struct tb_switch *sw = tb_to_switch(dev);
750 
751 		tb_switch_tmu_configure(sw, *(enum tb_switch_tmu_rate *)rate,
752 					tb_switch_is_clx_enabled(sw, TB_CL1));
753 		if (tb_switch_tmu_enable(sw))
754 			tb_sw_dbg(sw, "fail switching TMU mode for 1st depth router\n");
755 	}
756 
757 	return 0;
758 }
759 
760 /**
761  * tb_switch_enable_tmu_1st_child - Configure and enable TMU for 1st chidren
762  * @sw: The router to configure and enable it's children TMU
763  * @rate: Rate of the TMU to configure the router's chidren to
764  *
765  * Configures and enables the TMU mode of 1st depth children of the specified
766  * router to the specified rate.
767  */
768 void tb_switch_enable_tmu_1st_child(struct tb_switch *sw,
769 				    enum tb_switch_tmu_rate rate)
770 {
771 	device_for_each_child(&sw->dev, &rate,
772 			      tb_switch_tmu_config_enable);
773 }
774