xref: /linux/drivers/thunderbolt/tmu.c (revision 6093a688a07da07808f0122f9aa2a3eed250d853)
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 const unsigned int tmu_rates[] = {
15 	[TB_SWITCH_TMU_MODE_OFF] = 0,
16 	[TB_SWITCH_TMU_MODE_LOWRES] = 1000,
17 	[TB_SWITCH_TMU_MODE_HIFI_UNI] = 16,
18 	[TB_SWITCH_TMU_MODE_HIFI_BI] = 16,
19 	[TB_SWITCH_TMU_MODE_MEDRES_ENHANCED_UNI] = 16,
20 };
21 
22 static const struct {
23 	unsigned int freq_meas_window;
24 	unsigned int avg_const;
25 	unsigned int delta_avg_const;
26 	unsigned int repl_timeout;
27 	unsigned int repl_threshold;
28 	unsigned int repl_n;
29 	unsigned int dirswitch_n;
30 } tmu_params[] = {
31 	[TB_SWITCH_TMU_MODE_OFF] = { },
32 	[TB_SWITCH_TMU_MODE_LOWRES] = { 30, 4, },
33 	[TB_SWITCH_TMU_MODE_HIFI_UNI] = { 800, 8, },
34 	[TB_SWITCH_TMU_MODE_HIFI_BI] = { 800, 8, },
35 	[TB_SWITCH_TMU_MODE_MEDRES_ENHANCED_UNI] = {
36 		800, 4, 0, 3125, 25, 128, 255,
37 	},
38 };
39 
40 static const char *tmu_mode_name(enum tb_switch_tmu_mode mode)
41 {
42 	switch (mode) {
43 	case TB_SWITCH_TMU_MODE_OFF:
44 		return "off";
45 	case TB_SWITCH_TMU_MODE_LOWRES:
46 		return "uni-directional, LowRes";
47 	case TB_SWITCH_TMU_MODE_HIFI_UNI:
48 		return "uni-directional, HiFi";
49 	case TB_SWITCH_TMU_MODE_HIFI_BI:
50 		return "bi-directional, HiFi";
51 	case TB_SWITCH_TMU_MODE_MEDRES_ENHANCED_UNI:
52 		return "enhanced uni-directional, MedRes";
53 	default:
54 		return "unknown";
55 	}
56 }
57 
58 static bool tb_switch_tmu_enhanced_is_supported(const struct tb_switch *sw)
59 {
60 	return usb4_switch_version(sw) > 1;
61 }
62 
63 static int tb_switch_set_tmu_mode_params(struct tb_switch *sw,
64 					 enum tb_switch_tmu_mode mode)
65 {
66 	u32 freq, avg, val;
67 	int ret;
68 
69 	freq = tmu_params[mode].freq_meas_window;
70 	avg = tmu_params[mode].avg_const;
71 
72 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
73 			 sw->tmu.cap + TMU_RTR_CS_0, 1);
74 	if (ret)
75 		return ret;
76 
77 	val &= ~TMU_RTR_CS_0_FREQ_WIND_MASK;
78 	val |= FIELD_PREP(TMU_RTR_CS_0_FREQ_WIND_MASK, freq);
79 
80 	ret = tb_sw_write(sw, &val, TB_CFG_SWITCH,
81 			  sw->tmu.cap + TMU_RTR_CS_0, 1);
82 	if (ret)
83 		return ret;
84 
85 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
86 			 sw->tmu.cap + TMU_RTR_CS_15, 1);
87 	if (ret)
88 		return ret;
89 
90 	val &= ~TMU_RTR_CS_15_FREQ_AVG_MASK &
91 		~TMU_RTR_CS_15_DELAY_AVG_MASK &
92 		~TMU_RTR_CS_15_OFFSET_AVG_MASK &
93 		~TMU_RTR_CS_15_ERROR_AVG_MASK;
94 	val |=  FIELD_PREP(TMU_RTR_CS_15_FREQ_AVG_MASK, avg) |
95 		FIELD_PREP(TMU_RTR_CS_15_DELAY_AVG_MASK, avg) |
96 		FIELD_PREP(TMU_RTR_CS_15_OFFSET_AVG_MASK, avg) |
97 		FIELD_PREP(TMU_RTR_CS_15_ERROR_AVG_MASK, avg);
98 
99 	ret = tb_sw_write(sw, &val, TB_CFG_SWITCH,
100 			 sw->tmu.cap + TMU_RTR_CS_15, 1);
101 	if (ret)
102 		return ret;
103 
104 	if (tb_switch_tmu_enhanced_is_supported(sw)) {
105 		u32 delta_avg = tmu_params[mode].delta_avg_const;
106 
107 		ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
108 				 sw->tmu.cap + TMU_RTR_CS_18, 1);
109 		if (ret)
110 			return ret;
111 
112 		val &= ~TMU_RTR_CS_18_DELTA_AVG_CONST_MASK;
113 		val |= FIELD_PREP(TMU_RTR_CS_18_DELTA_AVG_CONST_MASK, delta_avg);
114 
115 		ret = tb_sw_write(sw, &val, TB_CFG_SWITCH,
116 				  sw->tmu.cap + TMU_RTR_CS_18, 1);
117 	}
118 
119 	return ret;
120 }
121 
122 static bool tb_switch_tmu_ucap_is_supported(struct tb_switch *sw)
123 {
124 	int ret;
125 	u32 val;
126 
127 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
128 			 sw->tmu.cap + TMU_RTR_CS_0, 1);
129 	if (ret)
130 		return false;
131 
132 	return !!(val & TMU_RTR_CS_0_UCAP);
133 }
134 
135 static int tb_switch_tmu_rate_read(struct tb_switch *sw)
136 {
137 	int ret;
138 	u32 val;
139 
140 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
141 			 sw->tmu.cap + TMU_RTR_CS_3, 1);
142 	if (ret)
143 		return ret;
144 
145 	val >>= TMU_RTR_CS_3_TS_PACKET_INTERVAL_SHIFT;
146 	return val;
147 }
148 
149 static int tb_switch_tmu_rate_write(struct tb_switch *sw, int rate)
150 {
151 	int ret;
152 	u32 val;
153 
154 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
155 			 sw->tmu.cap + TMU_RTR_CS_3, 1);
156 	if (ret)
157 		return ret;
158 
159 	val &= ~TMU_RTR_CS_3_TS_PACKET_INTERVAL_MASK;
160 	val |= rate << TMU_RTR_CS_3_TS_PACKET_INTERVAL_SHIFT;
161 
162 	return tb_sw_write(sw, &val, TB_CFG_SWITCH,
163 			   sw->tmu.cap + TMU_RTR_CS_3, 1);
164 }
165 
166 static int tb_port_tmu_write(struct tb_port *port, u8 offset, u32 mask,
167 			     u32 value)
168 {
169 	u32 data;
170 	int ret;
171 
172 	ret = tb_port_read(port, &data, TB_CFG_PORT, port->cap_tmu + offset, 1);
173 	if (ret)
174 		return ret;
175 
176 	data &= ~mask;
177 	data |= value;
178 
179 	return tb_port_write(port, &data, TB_CFG_PORT,
180 			     port->cap_tmu + offset, 1);
181 }
182 
183 static int tb_port_tmu_set_unidirectional(struct tb_port *port,
184 					  bool unidirectional)
185 {
186 	u32 val;
187 
188 	if (!port->sw->tmu.has_ucap)
189 		return 0;
190 
191 	val = unidirectional ? TMU_ADP_CS_3_UDM : 0;
192 	return tb_port_tmu_write(port, TMU_ADP_CS_3, TMU_ADP_CS_3_UDM, val);
193 }
194 
195 static inline int tb_port_tmu_unidirectional_disable(struct tb_port *port)
196 {
197 	return tb_port_tmu_set_unidirectional(port, false);
198 }
199 
200 static inline int tb_port_tmu_unidirectional_enable(struct tb_port *port)
201 {
202 	return tb_port_tmu_set_unidirectional(port, true);
203 }
204 
205 static bool tb_port_tmu_is_unidirectional(struct tb_port *port)
206 {
207 	int ret;
208 	u32 val;
209 
210 	ret = tb_port_read(port, &val, TB_CFG_PORT,
211 			   port->cap_tmu + TMU_ADP_CS_3, 1);
212 	if (ret)
213 		return false;
214 
215 	return val & TMU_ADP_CS_3_UDM;
216 }
217 
218 static bool tb_port_tmu_is_enhanced(struct tb_port *port)
219 {
220 	int ret;
221 	u32 val;
222 
223 	ret = tb_port_read(port, &val, TB_CFG_PORT,
224 			   port->cap_tmu + TMU_ADP_CS_8, 1);
225 	if (ret)
226 		return false;
227 
228 	return val & TMU_ADP_CS_8_EUDM;
229 }
230 
231 /* Can be called to non-v2 lane adapters too */
232 static int tb_port_tmu_enhanced_enable(struct tb_port *port, bool enable)
233 {
234 	int ret;
235 	u32 val;
236 
237 	if (!tb_switch_tmu_enhanced_is_supported(port->sw))
238 		return 0;
239 
240 	ret = tb_port_read(port, &val, TB_CFG_PORT,
241 			   port->cap_tmu + TMU_ADP_CS_8, 1);
242 	if (ret)
243 		return ret;
244 
245 	if (enable)
246 		val |= TMU_ADP_CS_8_EUDM;
247 	else
248 		val &= ~TMU_ADP_CS_8_EUDM;
249 
250 	return tb_port_write(port, &val, TB_CFG_PORT,
251 			     port->cap_tmu + TMU_ADP_CS_8, 1);
252 }
253 
254 static int tb_port_set_tmu_mode_params(struct tb_port *port,
255 				       enum tb_switch_tmu_mode mode)
256 {
257 	u32 repl_timeout, repl_threshold, repl_n, dirswitch_n, val;
258 	int ret;
259 
260 	repl_timeout = tmu_params[mode].repl_timeout;
261 	repl_threshold = tmu_params[mode].repl_threshold;
262 	repl_n = tmu_params[mode].repl_n;
263 	dirswitch_n = tmu_params[mode].dirswitch_n;
264 
265 	ret = tb_port_read(port, &val, TB_CFG_PORT,
266 			   port->cap_tmu + TMU_ADP_CS_8, 1);
267 	if (ret)
268 		return ret;
269 
270 	val &= ~TMU_ADP_CS_8_REPL_TIMEOUT_MASK;
271 	val &= ~TMU_ADP_CS_8_REPL_THRESHOLD_MASK;
272 	val |= FIELD_PREP(TMU_ADP_CS_8_REPL_TIMEOUT_MASK, repl_timeout);
273 	val |= FIELD_PREP(TMU_ADP_CS_8_REPL_THRESHOLD_MASK, repl_threshold);
274 
275 	ret = tb_port_write(port, &val, TB_CFG_PORT,
276 			    port->cap_tmu + TMU_ADP_CS_8, 1);
277 	if (ret)
278 		return ret;
279 
280 	ret = tb_port_read(port, &val, TB_CFG_PORT,
281 			   port->cap_tmu + TMU_ADP_CS_9, 1);
282 	if (ret)
283 		return ret;
284 
285 	val &= ~TMU_ADP_CS_9_REPL_N_MASK;
286 	val &= ~TMU_ADP_CS_9_DIRSWITCH_N_MASK;
287 	val |= FIELD_PREP(TMU_ADP_CS_9_REPL_N_MASK, repl_n);
288 	val |= FIELD_PREP(TMU_ADP_CS_9_DIRSWITCH_N_MASK, dirswitch_n);
289 
290 	return tb_port_write(port, &val, TB_CFG_PORT,
291 			     port->cap_tmu + TMU_ADP_CS_9, 1);
292 }
293 
294 /* Can be called to non-v2 lane adapters too */
295 static int tb_port_tmu_rate_write(struct tb_port *port, int rate)
296 {
297 	int ret;
298 	u32 val;
299 
300 	if (!tb_switch_tmu_enhanced_is_supported(port->sw))
301 		return 0;
302 
303 	ret = tb_port_read(port, &val, TB_CFG_PORT,
304 			   port->cap_tmu + TMU_ADP_CS_9, 1);
305 	if (ret)
306 		return ret;
307 
308 	val &= ~TMU_ADP_CS_9_ADP_TS_INTERVAL_MASK;
309 	val |= FIELD_PREP(TMU_ADP_CS_9_ADP_TS_INTERVAL_MASK, rate);
310 
311 	return tb_port_write(port, &val, TB_CFG_PORT,
312 			     port->cap_tmu + TMU_ADP_CS_9, 1);
313 }
314 
315 static int tb_port_tmu_time_sync(struct tb_port *port, bool time_sync)
316 {
317 	u32 val = time_sync ? TMU_ADP_CS_6_DTS : 0;
318 
319 	return tb_port_tmu_write(port, TMU_ADP_CS_6, TMU_ADP_CS_6_DTS, val);
320 }
321 
322 static int tb_port_tmu_time_sync_disable(struct tb_port *port)
323 {
324 	return tb_port_tmu_time_sync(port, true);
325 }
326 
327 static int tb_port_tmu_time_sync_enable(struct tb_port *port)
328 {
329 	return tb_port_tmu_time_sync(port, false);
330 }
331 
332 static int tb_switch_tmu_set_time_disruption(struct tb_switch *sw, bool set)
333 {
334 	u32 val, offset, bit;
335 	int ret;
336 
337 	if (tb_switch_is_usb4(sw)) {
338 		offset = sw->tmu.cap + TMU_RTR_CS_0;
339 		bit = TMU_RTR_CS_0_TD;
340 	} else {
341 		offset = sw->cap_vsec_tmu + TB_TIME_VSEC_3_CS_26;
342 		bit = TB_TIME_VSEC_3_CS_26_TD;
343 	}
344 
345 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, offset, 1);
346 	if (ret)
347 		return ret;
348 
349 	if (set)
350 		val |= bit;
351 	else
352 		val &= ~bit;
353 
354 	return tb_sw_write(sw, &val, TB_CFG_SWITCH, offset, 1);
355 }
356 
357 static int tmu_mode_init(struct tb_switch *sw)
358 {
359 	bool enhanced, ucap;
360 	int ret, rate;
361 
362 	ucap = tb_switch_tmu_ucap_is_supported(sw);
363 	if (ucap)
364 		tb_sw_dbg(sw, "TMU: supports uni-directional mode\n");
365 	enhanced = tb_switch_tmu_enhanced_is_supported(sw);
366 	if (enhanced)
367 		tb_sw_dbg(sw, "TMU: supports enhanced uni-directional mode\n");
368 
369 	ret = tb_switch_tmu_rate_read(sw);
370 	if (ret < 0)
371 		return ret;
372 	rate = ret;
373 
374 	/* Off by default */
375 	sw->tmu.mode = TB_SWITCH_TMU_MODE_OFF;
376 
377 	if (tb_route(sw)) {
378 		struct tb_port *up = tb_upstream_port(sw);
379 
380 		if (enhanced && tb_port_tmu_is_enhanced(up)) {
381 			sw->tmu.mode = TB_SWITCH_TMU_MODE_MEDRES_ENHANCED_UNI;
382 		} else if (ucap && tb_port_tmu_is_unidirectional(up)) {
383 			if (tmu_rates[TB_SWITCH_TMU_MODE_LOWRES] == rate)
384 				sw->tmu.mode = TB_SWITCH_TMU_MODE_LOWRES;
385 			else if (tmu_rates[TB_SWITCH_TMU_MODE_HIFI_UNI] == rate)
386 				sw->tmu.mode = TB_SWITCH_TMU_MODE_HIFI_UNI;
387 		} else if (rate) {
388 			sw->tmu.mode = TB_SWITCH_TMU_MODE_HIFI_BI;
389 		}
390 	} else if (rate) {
391 		sw->tmu.mode = TB_SWITCH_TMU_MODE_HIFI_BI;
392 	}
393 
394 	/* Update the initial request to match the current mode */
395 	sw->tmu.mode_request = sw->tmu.mode;
396 	sw->tmu.has_ucap = ucap;
397 
398 	return 0;
399 }
400 
401 /**
402  * tb_switch_tmu_init() - Initialize switch TMU structures
403  * @sw: Switch to initialized
404  *
405  * This function must be called before other TMU related functions to
406  * makes the internal structures are filled in correctly. Does not
407  * change any hardware configuration.
408  *
409  * Return: %0 on success, negative errno otherwise.
410  */
411 int tb_switch_tmu_init(struct tb_switch *sw)
412 {
413 	struct tb_port *port;
414 	int ret;
415 
416 	if (tb_switch_is_icm(sw))
417 		return 0;
418 
419 	ret = tb_switch_find_cap(sw, TB_SWITCH_CAP_TMU);
420 	if (ret > 0)
421 		sw->tmu.cap = ret;
422 
423 	tb_switch_for_each_port(sw, port) {
424 		int cap;
425 
426 		cap = tb_port_find_cap(port, TB_PORT_CAP_TIME1);
427 		if (cap > 0)
428 			port->cap_tmu = cap;
429 	}
430 
431 	ret = tmu_mode_init(sw);
432 	if (ret)
433 		return ret;
434 
435 	tb_sw_dbg(sw, "TMU: current mode: %s\n", tmu_mode_name(sw->tmu.mode));
436 	return 0;
437 }
438 
439 /**
440  * tb_switch_tmu_post_time() - Update switch local time
441  * @sw: Switch whose time to update
442  *
443  * Updates switch local time using time posting procedure.
444  *
445  * Return: %0 on success, negative errno otherwise.
446  */
447 int tb_switch_tmu_post_time(struct tb_switch *sw)
448 {
449 	unsigned int post_time_high_offset, post_time_high = 0;
450 	unsigned int post_local_time_offset, post_time_offset;
451 	struct tb_switch *root_switch = sw->tb->root_switch;
452 	u64 hi, mid, lo, local_time, post_time;
453 	int i, ret, retries = 100;
454 	u32 gm_local_time[3];
455 
456 	if (!tb_route(sw))
457 		return 0;
458 
459 	if (!tb_switch_is_usb4(sw))
460 		return 0;
461 
462 	/* Need to be able to read the grand master time */
463 	if (!root_switch->tmu.cap)
464 		return 0;
465 
466 	ret = tb_sw_read(root_switch, gm_local_time, TB_CFG_SWITCH,
467 			 root_switch->tmu.cap + TMU_RTR_CS_1,
468 			 ARRAY_SIZE(gm_local_time));
469 	if (ret)
470 		return ret;
471 
472 	for (i = 0; i < ARRAY_SIZE(gm_local_time); i++)
473 		tb_sw_dbg(root_switch, "TMU: local_time[%d]=0x%08x\n", i,
474 			  gm_local_time[i]);
475 
476 	/* Convert to nanoseconds (drop fractional part) */
477 	hi = gm_local_time[2] & TMU_RTR_CS_3_LOCAL_TIME_NS_MASK;
478 	mid = gm_local_time[1];
479 	lo = (gm_local_time[0] & TMU_RTR_CS_1_LOCAL_TIME_NS_MASK) >>
480 		TMU_RTR_CS_1_LOCAL_TIME_NS_SHIFT;
481 	local_time = hi << 48 | mid << 16 | lo;
482 
483 	/* Tell the switch that time sync is disrupted for a while */
484 	ret = tb_switch_tmu_set_time_disruption(sw, true);
485 	if (ret)
486 		return ret;
487 
488 	post_local_time_offset = sw->tmu.cap + TMU_RTR_CS_22;
489 	post_time_offset = sw->tmu.cap + TMU_RTR_CS_24;
490 	post_time_high_offset = sw->tmu.cap + TMU_RTR_CS_25;
491 
492 	/*
493 	 * Write the Grandmaster time to the Post Local Time registers
494 	 * of the new switch.
495 	 */
496 	ret = tb_sw_write(sw, &local_time, TB_CFG_SWITCH,
497 			  post_local_time_offset, 2);
498 	if (ret)
499 		goto out;
500 
501 	/*
502 	 * Have the new switch update its local time by:
503 	 * 1) writing 0x1 to the Post Time Low register and 0xffffffff to
504 	 * Post Time High register.
505 	 * 2) write 0 to Post Time High register and then wait for
506 	 * the completion of the post_time register becomes 0.
507 	 * This means the time has been converged properly.
508 	 */
509 	post_time = 0xffffffff00000001ULL;
510 
511 	ret = tb_sw_write(sw, &post_time, TB_CFG_SWITCH, post_time_offset, 2);
512 	if (ret)
513 		goto out;
514 
515 	ret = tb_sw_write(sw, &post_time_high, TB_CFG_SWITCH,
516 			  post_time_high_offset, 1);
517 	if (ret)
518 		goto out;
519 
520 	do {
521 		usleep_range(5, 10);
522 		ret = tb_sw_read(sw, &post_time, TB_CFG_SWITCH,
523 				 post_time_offset, 2);
524 		if (ret)
525 			goto out;
526 	} while (--retries && post_time);
527 
528 	if (!retries) {
529 		ret = -ETIMEDOUT;
530 		goto out;
531 	}
532 
533 	tb_sw_dbg(sw, "TMU: updated local time to %#llx\n", local_time);
534 
535 out:
536 	tb_switch_tmu_set_time_disruption(sw, false);
537 	return ret;
538 }
539 
540 static int disable_enhanced(struct tb_port *up, struct tb_port *down)
541 {
542 	int ret;
543 
544 	/*
545 	 * Router may already been disconnected so ignore errors on the
546 	 * upstream port.
547 	 */
548 	tb_port_tmu_rate_write(up, 0);
549 	tb_port_tmu_enhanced_enable(up, false);
550 
551 	ret = tb_port_tmu_rate_write(down, 0);
552 	if (ret)
553 		return ret;
554 	return tb_port_tmu_enhanced_enable(down, false);
555 }
556 
557 /**
558  * tb_switch_tmu_disable() - Disable TMU of a switch
559  * @sw: Switch whose TMU to disable
560  *
561  * Turns off TMU of @sw if it is enabled. If not enabled does nothing.
562  *
563  * Return: %0 on success, negative errno otherwise.
564  */
565 int tb_switch_tmu_disable(struct tb_switch *sw)
566 {
567 	/* Already disabled? */
568 	if (sw->tmu.mode == TB_SWITCH_TMU_MODE_OFF)
569 		return 0;
570 
571 	if (tb_route(sw)) {
572 		struct tb_port *down, *up;
573 		int ret;
574 
575 		down = tb_switch_downstream_port(sw);
576 		up = tb_upstream_port(sw);
577 		/*
578 		 * In case of uni-directional time sync, TMU handshake is
579 		 * initiated by upstream router. In case of bi-directional
580 		 * time sync, TMU handshake is initiated by downstream router.
581 		 * We change downstream router's rate to off for both uni/bidir
582 		 * cases although it is needed only for the bi-directional mode.
583 		 * We avoid changing upstream router's mode since it might
584 		 * have another downstream router plugged, that is set to
585 		 * uni-directional mode and we don't want to change it's TMU
586 		 * mode.
587 		 */
588 		ret = tb_switch_tmu_rate_write(sw, tmu_rates[TB_SWITCH_TMU_MODE_OFF]);
589 		if (ret)
590 			return ret;
591 
592 		tb_port_tmu_time_sync_disable(up);
593 		ret = tb_port_tmu_time_sync_disable(down);
594 		if (ret)
595 			return ret;
596 
597 		switch (sw->tmu.mode) {
598 		case TB_SWITCH_TMU_MODE_LOWRES:
599 		case TB_SWITCH_TMU_MODE_HIFI_UNI:
600 			/* The switch may be unplugged so ignore any errors */
601 			tb_port_tmu_unidirectional_disable(up);
602 			ret = tb_port_tmu_unidirectional_disable(down);
603 			if (ret)
604 				return ret;
605 			break;
606 
607 		case TB_SWITCH_TMU_MODE_MEDRES_ENHANCED_UNI:
608 			ret = disable_enhanced(up, down);
609 			if (ret)
610 				return ret;
611 			break;
612 
613 		default:
614 			break;
615 		}
616 	} else {
617 		tb_switch_tmu_rate_write(sw, tmu_rates[TB_SWITCH_TMU_MODE_OFF]);
618 	}
619 
620 	sw->tmu.mode = TB_SWITCH_TMU_MODE_OFF;
621 
622 	tb_sw_dbg(sw, "TMU: disabled\n");
623 	return 0;
624 }
625 
626 /* Called only when there is failure enabling requested mode */
627 static void tb_switch_tmu_off(struct tb_switch *sw)
628 {
629 	unsigned int rate = tmu_rates[TB_SWITCH_TMU_MODE_OFF];
630 	struct tb_port *down, *up;
631 
632 	down = tb_switch_downstream_port(sw);
633 	up = tb_upstream_port(sw);
634 	/*
635 	 * In case of any failure in one of the steps when setting
636 	 * bi-directional or uni-directional TMU mode, get back to the TMU
637 	 * configurations in off mode. In case of additional failures in
638 	 * the functions below, ignore them since the caller shall already
639 	 * report a failure.
640 	 */
641 	tb_port_tmu_time_sync_disable(down);
642 	tb_port_tmu_time_sync_disable(up);
643 
644 	switch (sw->tmu.mode_request) {
645 	case TB_SWITCH_TMU_MODE_LOWRES:
646 	case TB_SWITCH_TMU_MODE_HIFI_UNI:
647 		tb_switch_tmu_rate_write(tb_switch_parent(sw), rate);
648 		break;
649 	case TB_SWITCH_TMU_MODE_MEDRES_ENHANCED_UNI:
650 		disable_enhanced(up, down);
651 		break;
652 	default:
653 		break;
654 	}
655 
656 	/* Always set the rate to 0 */
657 	tb_switch_tmu_rate_write(sw, rate);
658 
659 	tb_switch_set_tmu_mode_params(sw, sw->tmu.mode);
660 	tb_port_tmu_unidirectional_disable(down);
661 	tb_port_tmu_unidirectional_disable(up);
662 }
663 
664 /*
665  * This function is called when the previous TMU mode was
666  * TB_SWITCH_TMU_MODE_OFF.
667  */
668 static int tb_switch_tmu_enable_bidirectional(struct tb_switch *sw)
669 {
670 	struct tb_port *up, *down;
671 	int ret;
672 
673 	up = tb_upstream_port(sw);
674 	down = tb_switch_downstream_port(sw);
675 
676 	ret = tb_port_tmu_unidirectional_disable(up);
677 	if (ret)
678 		return ret;
679 
680 	ret = tb_port_tmu_unidirectional_disable(down);
681 	if (ret)
682 		goto out;
683 
684 	ret = tb_switch_tmu_rate_write(sw, tmu_rates[TB_SWITCH_TMU_MODE_HIFI_BI]);
685 	if (ret)
686 		goto out;
687 
688 	ret = tb_port_tmu_time_sync_enable(up);
689 	if (ret)
690 		goto out;
691 
692 	ret = tb_port_tmu_time_sync_enable(down);
693 	if (ret)
694 		goto out;
695 
696 	return 0;
697 
698 out:
699 	tb_switch_tmu_off(sw);
700 	return ret;
701 }
702 
703 /* Only needed for Titan Ridge */
704 static int tb_switch_tmu_disable_objections(struct tb_switch *sw)
705 {
706 	struct tb_port *up = tb_upstream_port(sw);
707 	u32 val;
708 	int ret;
709 
710 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
711 			 sw->cap_vsec_tmu + TB_TIME_VSEC_3_CS_9, 1);
712 	if (ret)
713 		return ret;
714 
715 	val &= ~TB_TIME_VSEC_3_CS_9_TMU_OBJ_MASK;
716 
717 	ret = tb_sw_write(sw, &val, TB_CFG_SWITCH,
718 			  sw->cap_vsec_tmu + TB_TIME_VSEC_3_CS_9, 1);
719 	if (ret)
720 		return ret;
721 
722 	return tb_port_tmu_write(up, TMU_ADP_CS_6,
723 				 TMU_ADP_CS_6_DISABLE_TMU_OBJ_MASK,
724 				 TMU_ADP_CS_6_DISABLE_TMU_OBJ_CL1 |
725 				 TMU_ADP_CS_6_DISABLE_TMU_OBJ_CL2);
726 }
727 
728 /*
729  * This function is called when the previous TMU mode was
730  * TB_SWITCH_TMU_MODE_OFF.
731  */
732 static int tb_switch_tmu_enable_unidirectional(struct tb_switch *sw)
733 {
734 	struct tb_port *up, *down;
735 	int ret;
736 
737 	up = tb_upstream_port(sw);
738 	down = tb_switch_downstream_port(sw);
739 	ret = tb_switch_tmu_rate_write(tb_switch_parent(sw),
740 				       tmu_rates[sw->tmu.mode_request]);
741 	if (ret)
742 		return ret;
743 
744 	ret = tb_switch_set_tmu_mode_params(sw, sw->tmu.mode_request);
745 	if (ret)
746 		return ret;
747 
748 	ret = tb_port_tmu_unidirectional_enable(up);
749 	if (ret)
750 		goto out;
751 
752 	ret = tb_port_tmu_time_sync_enable(up);
753 	if (ret)
754 		goto out;
755 
756 	ret = tb_port_tmu_unidirectional_enable(down);
757 	if (ret)
758 		goto out;
759 
760 	ret = tb_port_tmu_time_sync_enable(down);
761 	if (ret)
762 		goto out;
763 
764 	return 0;
765 
766 out:
767 	tb_switch_tmu_off(sw);
768 	return ret;
769 }
770 
771 /*
772  * This function is called when the previous TMU mode was
773  * TB_SWITCH_TMU_RATE_OFF.
774  */
775 static int tb_switch_tmu_enable_enhanced(struct tb_switch *sw)
776 {
777 	unsigned int rate = tmu_rates[sw->tmu.mode_request];
778 	struct tb_port *up, *down;
779 	int ret;
780 
781 	/* Router specific parameters first */
782 	ret = tb_switch_set_tmu_mode_params(sw, sw->tmu.mode_request);
783 	if (ret)
784 		return ret;
785 
786 	up = tb_upstream_port(sw);
787 	down = tb_switch_downstream_port(sw);
788 
789 	ret = tb_port_set_tmu_mode_params(up, sw->tmu.mode_request);
790 	if (ret)
791 		goto out;
792 
793 	ret = tb_port_tmu_rate_write(up, rate);
794 	if (ret)
795 		goto out;
796 
797 	ret = tb_port_tmu_enhanced_enable(up, true);
798 	if (ret)
799 		goto out;
800 
801 	ret = tb_port_set_tmu_mode_params(down, sw->tmu.mode_request);
802 	if (ret)
803 		goto out;
804 
805 	ret = tb_port_tmu_rate_write(down, rate);
806 	if (ret)
807 		goto out;
808 
809 	ret = tb_port_tmu_enhanced_enable(down, true);
810 	if (ret)
811 		goto out;
812 
813 	return 0;
814 
815 out:
816 	tb_switch_tmu_off(sw);
817 	return ret;
818 }
819 
820 static void tb_switch_tmu_change_mode_prev(struct tb_switch *sw)
821 {
822 	unsigned int rate = tmu_rates[sw->tmu.mode];
823 	struct tb_port *down, *up;
824 
825 	down = tb_switch_downstream_port(sw);
826 	up = tb_upstream_port(sw);
827 	/*
828 	 * In case of any failure in one of the steps when change mode,
829 	 * get back to the TMU configurations in previous mode.
830 	 * In case of additional failures in the functions below,
831 	 * ignore them since the caller shall already report a failure.
832 	 */
833 	switch (sw->tmu.mode) {
834 	case TB_SWITCH_TMU_MODE_LOWRES:
835 	case TB_SWITCH_TMU_MODE_HIFI_UNI:
836 		tb_port_tmu_set_unidirectional(down, true);
837 		tb_switch_tmu_rate_write(tb_switch_parent(sw), rate);
838 		break;
839 
840 	case TB_SWITCH_TMU_MODE_HIFI_BI:
841 		tb_port_tmu_set_unidirectional(down, false);
842 		tb_switch_tmu_rate_write(sw, rate);
843 		break;
844 
845 	default:
846 		break;
847 	}
848 
849 	tb_switch_set_tmu_mode_params(sw, sw->tmu.mode);
850 
851 	switch (sw->tmu.mode) {
852 	case TB_SWITCH_TMU_MODE_LOWRES:
853 	case TB_SWITCH_TMU_MODE_HIFI_UNI:
854 		tb_port_tmu_set_unidirectional(up, true);
855 		break;
856 
857 	case TB_SWITCH_TMU_MODE_HIFI_BI:
858 		tb_port_tmu_set_unidirectional(up, false);
859 		break;
860 
861 	default:
862 		break;
863 	}
864 }
865 
866 static int tb_switch_tmu_change_mode(struct tb_switch *sw)
867 {
868 	unsigned int rate = tmu_rates[sw->tmu.mode_request];
869 	struct tb_port *up, *down;
870 	int ret;
871 
872 	up = tb_upstream_port(sw);
873 	down = tb_switch_downstream_port(sw);
874 
875 	/* Program the upstream router downstream facing lane adapter */
876 	switch (sw->tmu.mode_request) {
877 	case TB_SWITCH_TMU_MODE_LOWRES:
878 	case TB_SWITCH_TMU_MODE_HIFI_UNI:
879 		ret = tb_port_tmu_set_unidirectional(down, true);
880 		if (ret)
881 			goto out;
882 		ret = tb_switch_tmu_rate_write(tb_switch_parent(sw), rate);
883 		if (ret)
884 			goto out;
885 		break;
886 
887 	case TB_SWITCH_TMU_MODE_HIFI_BI:
888 		ret = tb_port_tmu_set_unidirectional(down, false);
889 		if (ret)
890 			goto out;
891 		ret = tb_switch_tmu_rate_write(sw, rate);
892 		if (ret)
893 			goto out;
894 		break;
895 
896 	default:
897 		/* Not allowed to change modes from other than above */
898 		return -EINVAL;
899 	}
900 
901 	ret = tb_switch_set_tmu_mode_params(sw, sw->tmu.mode_request);
902 	if (ret)
903 		goto out;
904 
905 	/* Program the new mode and the downstream router lane adapter */
906 	switch (sw->tmu.mode_request) {
907 	case TB_SWITCH_TMU_MODE_LOWRES:
908 	case TB_SWITCH_TMU_MODE_HIFI_UNI:
909 		ret = tb_port_tmu_set_unidirectional(up, true);
910 		if (ret)
911 			goto out;
912 		break;
913 
914 	case TB_SWITCH_TMU_MODE_HIFI_BI:
915 		ret = tb_port_tmu_set_unidirectional(up, false);
916 		if (ret)
917 			goto out;
918 		break;
919 
920 	default:
921 		/* Not allowed to change modes from other than above */
922 		return -EINVAL;
923 	}
924 
925 	ret = tb_port_tmu_time_sync_enable(down);
926 	if (ret)
927 		goto out;
928 
929 	ret = tb_port_tmu_time_sync_enable(up);
930 	if (ret)
931 		goto out;
932 
933 	return 0;
934 
935 out:
936 	tb_switch_tmu_change_mode_prev(sw);
937 	return ret;
938 }
939 
940 /**
941  * tb_switch_tmu_enable() - Enable TMU on a router
942  * @sw: Router whose TMU to enable
943  *
944  * Enables TMU of a router to be in uni-directional Normal/HiFi or
945  * bi-directional HiFi mode. Calling tb_switch_tmu_configure() is
946  * required before calling this function.
947  *
948  * Return: %0 on success, negative errno otherwise.
949  */
950 int tb_switch_tmu_enable(struct tb_switch *sw)
951 {
952 	int ret;
953 
954 	if (tb_switch_tmu_is_enabled(sw))
955 		return 0;
956 
957 	if (tb_switch_is_titan_ridge(sw) &&
958 	    (sw->tmu.mode_request == TB_SWITCH_TMU_MODE_LOWRES ||
959 	     sw->tmu.mode_request == TB_SWITCH_TMU_MODE_HIFI_UNI)) {
960 		ret = tb_switch_tmu_disable_objections(sw);
961 		if (ret)
962 			return ret;
963 	}
964 
965 	ret = tb_switch_tmu_set_time_disruption(sw, true);
966 	if (ret)
967 		return ret;
968 
969 	if (tb_route(sw)) {
970 		/*
971 		 * The used mode changes are from OFF to
972 		 * HiFi-Uni/HiFi-BiDir/Normal-Uni or from Normal-Uni to
973 		 * HiFi-Uni.
974 		 */
975 		if (sw->tmu.mode == TB_SWITCH_TMU_MODE_OFF) {
976 			switch (sw->tmu.mode_request) {
977 			case TB_SWITCH_TMU_MODE_LOWRES:
978 			case TB_SWITCH_TMU_MODE_HIFI_UNI:
979 				ret = tb_switch_tmu_enable_unidirectional(sw);
980 				break;
981 
982 			case TB_SWITCH_TMU_MODE_HIFI_BI:
983 				ret = tb_switch_tmu_enable_bidirectional(sw);
984 				break;
985 			case TB_SWITCH_TMU_MODE_MEDRES_ENHANCED_UNI:
986 				ret = tb_switch_tmu_enable_enhanced(sw);
987 				break;
988 			default:
989 				ret = -EINVAL;
990 				break;
991 			}
992 		} else if (sw->tmu.mode == TB_SWITCH_TMU_MODE_LOWRES ||
993 			   sw->tmu.mode == TB_SWITCH_TMU_MODE_HIFI_UNI ||
994 			   sw->tmu.mode == TB_SWITCH_TMU_MODE_HIFI_BI) {
995 			ret = tb_switch_tmu_change_mode(sw);
996 		} else {
997 			ret = -EINVAL;
998 		}
999 	} else {
1000 		/*
1001 		 * Host router port configurations are written as
1002 		 * part of configurations for downstream port of the parent
1003 		 * of the child node - see above.
1004 		 * Here only the host router' rate configuration is written.
1005 		 */
1006 		ret = tb_switch_tmu_rate_write(sw, tmu_rates[sw->tmu.mode_request]);
1007 	}
1008 
1009 	if (ret) {
1010 		tb_sw_warn(sw, "TMU: failed to enable mode %s: %d\n",
1011 			   tmu_mode_name(sw->tmu.mode_request), ret);
1012 	} else {
1013 		sw->tmu.mode = sw->tmu.mode_request;
1014 		tb_sw_dbg(sw, "TMU: mode set to: %s\n", tmu_mode_name(sw->tmu.mode));
1015 	}
1016 
1017 	return tb_switch_tmu_set_time_disruption(sw, false);
1018 }
1019 
1020 /**
1021  * tb_switch_tmu_configure() - Configure the TMU mode
1022  * @sw: Router whose mode to change
1023  * @mode: Mode to configure
1024  *
1025  * Selects the TMU mode that is enabled when tb_switch_tmu_enable() is
1026  * next called.
1027  *
1028  * Return:
1029  * * %0 - On success.
1030  * * %-EOPNOTSUPP - If the requested mode is not possible (not supported by
1031  *   the router and/or topology).
1032  * * Negative errno - Another error occurred.
1033  */
1034 int tb_switch_tmu_configure(struct tb_switch *sw, enum tb_switch_tmu_mode mode)
1035 {
1036 	switch (mode) {
1037 	case TB_SWITCH_TMU_MODE_OFF:
1038 		break;
1039 
1040 	case TB_SWITCH_TMU_MODE_LOWRES:
1041 	case TB_SWITCH_TMU_MODE_HIFI_UNI:
1042 		if (!sw->tmu.has_ucap)
1043 			return -EOPNOTSUPP;
1044 		break;
1045 
1046 	case TB_SWITCH_TMU_MODE_HIFI_BI:
1047 		break;
1048 
1049 	case TB_SWITCH_TMU_MODE_MEDRES_ENHANCED_UNI: {
1050 		const struct tb_switch *parent_sw = tb_switch_parent(sw);
1051 
1052 		if (!parent_sw || !tb_switch_tmu_enhanced_is_supported(parent_sw))
1053 			return -EOPNOTSUPP;
1054 		if (!tb_switch_tmu_enhanced_is_supported(sw))
1055 			return -EOPNOTSUPP;
1056 
1057 		break;
1058 	}
1059 
1060 	default:
1061 		tb_sw_warn(sw, "TMU: unsupported mode %u\n", mode);
1062 		return -EINVAL;
1063 	}
1064 
1065 	if (sw->tmu.mode_request != mode) {
1066 		tb_sw_dbg(sw, "TMU: mode change %s -> %s requested\n",
1067 			  tmu_mode_name(sw->tmu.mode), tmu_mode_name(mode));
1068 		sw->tmu.mode_request = mode;
1069 	}
1070 
1071 	return 0;
1072 }
1073