xref: /linux/drivers/thunderbolt/lc.c (revision 662fa3d6099374c4615bf64d06895e3573b935b2)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Thunderbolt link controller support
4  *
5  * Copyright (C) 2019, Intel Corporation
6  * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
7  */
8 
9 #include "tb.h"
10 
11 /**
12  * tb_lc_read_uuid() - Read switch UUID from link controller common register
13  * @sw: Switch whose UUID is read
14  * @uuid: UUID is placed here
15  */
16 int tb_lc_read_uuid(struct tb_switch *sw, u32 *uuid)
17 {
18 	if (!sw->cap_lc)
19 		return -EINVAL;
20 	return tb_sw_read(sw, uuid, TB_CFG_SWITCH, sw->cap_lc + TB_LC_FUSE, 4);
21 }
22 
23 static int read_lc_desc(struct tb_switch *sw, u32 *desc)
24 {
25 	if (!sw->cap_lc)
26 		return -EINVAL;
27 	return tb_sw_read(sw, desc, TB_CFG_SWITCH, sw->cap_lc + TB_LC_DESC, 1);
28 }
29 
30 static int find_port_lc_cap(struct tb_port *port)
31 {
32 	struct tb_switch *sw = port->sw;
33 	int start, phys, ret, size;
34 	u32 desc;
35 
36 	ret = read_lc_desc(sw, &desc);
37 	if (ret)
38 		return ret;
39 
40 	/* Start of port LC registers */
41 	start = (desc & TB_LC_DESC_SIZE_MASK) >> TB_LC_DESC_SIZE_SHIFT;
42 	size = (desc & TB_LC_DESC_PORT_SIZE_MASK) >> TB_LC_DESC_PORT_SIZE_SHIFT;
43 	phys = tb_phy_port_from_link(port->port);
44 
45 	return sw->cap_lc + start + phys * size;
46 }
47 
48 static int tb_lc_set_port_configured(struct tb_port *port, bool configured)
49 {
50 	bool upstream = tb_is_upstream_port(port);
51 	struct tb_switch *sw = port->sw;
52 	u32 ctrl, lane;
53 	int cap, ret;
54 
55 	if (sw->generation < 2)
56 		return 0;
57 
58 	cap = find_port_lc_cap(port);
59 	if (cap < 0)
60 		return cap;
61 
62 	ret = tb_sw_read(sw, &ctrl, TB_CFG_SWITCH, cap + TB_LC_SX_CTRL, 1);
63 	if (ret)
64 		return ret;
65 
66 	/* Resolve correct lane */
67 	if (port->port % 2)
68 		lane = TB_LC_SX_CTRL_L1C;
69 	else
70 		lane = TB_LC_SX_CTRL_L2C;
71 
72 	if (configured) {
73 		ctrl |= lane;
74 		if (upstream)
75 			ctrl |= TB_LC_SX_CTRL_UPSTREAM;
76 	} else {
77 		ctrl &= ~lane;
78 		if (upstream)
79 			ctrl &= ~TB_LC_SX_CTRL_UPSTREAM;
80 	}
81 
82 	return tb_sw_write(sw, &ctrl, TB_CFG_SWITCH, cap + TB_LC_SX_CTRL, 1);
83 }
84 
85 /**
86  * tb_lc_configure_port() - Let LC know about configured port
87  * @port: Port that is set as configured
88  *
89  * Sets the port configured for power management purposes.
90  */
91 int tb_lc_configure_port(struct tb_port *port)
92 {
93 	return tb_lc_set_port_configured(port, true);
94 }
95 
96 /**
97  * tb_lc_unconfigure_port() - Let LC know about unconfigured port
98  * @port: Port that is set as configured
99  *
100  * Sets the port unconfigured for power management purposes.
101  */
102 void tb_lc_unconfigure_port(struct tb_port *port)
103 {
104 	tb_lc_set_port_configured(port, false);
105 }
106 
107 static int tb_lc_set_xdomain_configured(struct tb_port *port, bool configure)
108 {
109 	struct tb_switch *sw = port->sw;
110 	u32 ctrl, lane;
111 	int cap, ret;
112 
113 	if (sw->generation < 2)
114 		return 0;
115 
116 	cap = find_port_lc_cap(port);
117 	if (cap < 0)
118 		return cap;
119 
120 	ret = tb_sw_read(sw, &ctrl, TB_CFG_SWITCH, cap + TB_LC_SX_CTRL, 1);
121 	if (ret)
122 		return ret;
123 
124 	/* Resolve correct lane */
125 	if (port->port % 2)
126 		lane = TB_LC_SX_CTRL_L1D;
127 	else
128 		lane = TB_LC_SX_CTRL_L2D;
129 
130 	if (configure)
131 		ctrl |= lane;
132 	else
133 		ctrl &= ~lane;
134 
135 	return tb_sw_write(sw, &ctrl, TB_CFG_SWITCH, cap + TB_LC_SX_CTRL, 1);
136 }
137 
138 /**
139  * tb_lc_configure_xdomain() - Inform LC that the link is XDomain
140  * @port: Switch downstream port connected to another host
141  *
142  * Sets the lane configured for XDomain accordingly so that the LC knows
143  * about this. Returns %0 in success and negative errno in failure.
144  */
145 int tb_lc_configure_xdomain(struct tb_port *port)
146 {
147 	return tb_lc_set_xdomain_configured(port, true);
148 }
149 
150 /**
151  * tb_lc_unconfigure_xdomain() - Unconfigure XDomain from port
152  * @port: Switch downstream port that was connected to another host
153  *
154  * Unsets the lane XDomain configuration.
155  */
156 void tb_lc_unconfigure_xdomain(struct tb_port *port)
157 {
158 	tb_lc_set_xdomain_configured(port, false);
159 }
160 
161 /**
162  * tb_lc_start_lane_initialization() - Start lane initialization
163  * @port: Device router lane 0 adapter
164  *
165  * Starts lane initialization for @port after the router resumed from
166  * sleep. Should be called for those downstream lane adapters that were
167  * not connected (tb_lc_configure_port() was not called) before sleep.
168  *
169  * Returns %0 in success and negative errno in case of failure.
170  */
171 int tb_lc_start_lane_initialization(struct tb_port *port)
172 {
173 	struct tb_switch *sw = port->sw;
174 	int ret, cap;
175 	u32 ctrl;
176 
177 	if (!tb_route(sw))
178 		return 0;
179 
180 	if (sw->generation < 2)
181 		return 0;
182 
183 	cap = find_port_lc_cap(port);
184 	if (cap < 0)
185 		return cap;
186 
187 	ret = tb_sw_read(sw, &ctrl, TB_CFG_SWITCH, cap + TB_LC_SX_CTRL, 1);
188 	if (ret)
189 		return ret;
190 
191 	ctrl |= TB_LC_SX_CTRL_SLI;
192 
193 	return tb_sw_write(sw, &ctrl, TB_CFG_SWITCH, cap + TB_LC_SX_CTRL, 1);
194 }
195 
196 static int tb_lc_set_wake_one(struct tb_switch *sw, unsigned int offset,
197 			      unsigned int flags)
198 {
199 	u32 ctrl;
200 	int ret;
201 
202 	/*
203 	 * Enable wake on PCIe and USB4 (wake coming from another
204 	 * router).
205 	 */
206 	ret = tb_sw_read(sw, &ctrl, TB_CFG_SWITCH,
207 			 offset + TB_LC_SX_CTRL, 1);
208 	if (ret)
209 		return ret;
210 
211 	ctrl &= ~(TB_LC_SX_CTRL_WOC | TB_LC_SX_CTRL_WOD | TB_LC_SX_CTRL_WODPC |
212 		  TB_LC_SX_CTRL_WODPD | TB_LC_SX_CTRL_WOP | TB_LC_SX_CTRL_WOU4);
213 
214 	if (flags & TB_WAKE_ON_CONNECT)
215 		ctrl |= TB_LC_SX_CTRL_WOC | TB_LC_SX_CTRL_WOD;
216 	if (flags & TB_WAKE_ON_USB4)
217 		ctrl |= TB_LC_SX_CTRL_WOU4;
218 	if (flags & TB_WAKE_ON_PCIE)
219 		ctrl |= TB_LC_SX_CTRL_WOP;
220 	if (flags & TB_WAKE_ON_DP)
221 		ctrl |= TB_LC_SX_CTRL_WODPC | TB_LC_SX_CTRL_WODPD;
222 
223 	return tb_sw_write(sw, &ctrl, TB_CFG_SWITCH, offset + TB_LC_SX_CTRL, 1);
224 }
225 
226 /**
227  * tb_lc_set_wake() - Enable/disable wake
228  * @sw: Switch whose wakes to configure
229  * @flags: Wakeup flags (%0 to disable)
230  *
231  * For each LC sets wake bits accordingly.
232  */
233 int tb_lc_set_wake(struct tb_switch *sw, unsigned int flags)
234 {
235 	int start, size, nlc, ret, i;
236 	u32 desc;
237 
238 	if (sw->generation < 2)
239 		return 0;
240 
241 	if (!tb_route(sw))
242 		return 0;
243 
244 	ret = read_lc_desc(sw, &desc);
245 	if (ret)
246 		return ret;
247 
248 	/* Figure out number of link controllers */
249 	nlc = desc & TB_LC_DESC_NLC_MASK;
250 	start = (desc & TB_LC_DESC_SIZE_MASK) >> TB_LC_DESC_SIZE_SHIFT;
251 	size = (desc & TB_LC_DESC_PORT_SIZE_MASK) >> TB_LC_DESC_PORT_SIZE_SHIFT;
252 
253 	/* For each link controller set sleep bit */
254 	for (i = 0; i < nlc; i++) {
255 		unsigned int offset = sw->cap_lc + start + i * size;
256 
257 		ret = tb_lc_set_wake_one(sw, offset, flags);
258 		if (ret)
259 			return ret;
260 	}
261 
262 	return 0;
263 }
264 
265 /**
266  * tb_lc_set_sleep() - Inform LC that the switch is going to sleep
267  * @sw: Switch to set sleep
268  *
269  * Let the switch link controllers know that the switch is going to
270  * sleep.
271  */
272 int tb_lc_set_sleep(struct tb_switch *sw)
273 {
274 	int start, size, nlc, ret, i;
275 	u32 desc;
276 
277 	if (sw->generation < 2)
278 		return 0;
279 
280 	ret = read_lc_desc(sw, &desc);
281 	if (ret)
282 		return ret;
283 
284 	/* Figure out number of link controllers */
285 	nlc = desc & TB_LC_DESC_NLC_MASK;
286 	start = (desc & TB_LC_DESC_SIZE_MASK) >> TB_LC_DESC_SIZE_SHIFT;
287 	size = (desc & TB_LC_DESC_PORT_SIZE_MASK) >> TB_LC_DESC_PORT_SIZE_SHIFT;
288 
289 	/* For each link controller set sleep bit */
290 	for (i = 0; i < nlc; i++) {
291 		unsigned int offset = sw->cap_lc + start + i * size;
292 		u32 ctrl;
293 
294 		ret = tb_sw_read(sw, &ctrl, TB_CFG_SWITCH,
295 				 offset + TB_LC_SX_CTRL, 1);
296 		if (ret)
297 			return ret;
298 
299 		ctrl |= TB_LC_SX_CTRL_SLP;
300 		ret = tb_sw_write(sw, &ctrl, TB_CFG_SWITCH,
301 				  offset + TB_LC_SX_CTRL, 1);
302 		if (ret)
303 			return ret;
304 	}
305 
306 	return 0;
307 }
308 
309 /**
310  * tb_lc_lane_bonding_possible() - Is lane bonding possible towards switch
311  * @sw: Switch to check
312  *
313  * Checks whether conditions for lane bonding from parent to @sw are
314  * possible.
315  */
316 bool tb_lc_lane_bonding_possible(struct tb_switch *sw)
317 {
318 	struct tb_port *up;
319 	int cap, ret;
320 	u32 val;
321 
322 	if (sw->generation < 2)
323 		return false;
324 
325 	up = tb_upstream_port(sw);
326 	cap = find_port_lc_cap(up);
327 	if (cap < 0)
328 		return false;
329 
330 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, cap + TB_LC_PORT_ATTR, 1);
331 	if (ret)
332 		return false;
333 
334 	return !!(val & TB_LC_PORT_ATTR_BE);
335 }
336 
337 static int tb_lc_dp_sink_from_port(const struct tb_switch *sw,
338 				   struct tb_port *in)
339 {
340 	struct tb_port *port;
341 
342 	/* The first DP IN port is sink 0 and second is sink 1 */
343 	tb_switch_for_each_port(sw, port) {
344 		if (tb_port_is_dpin(port))
345 			return in != port;
346 	}
347 
348 	return -EINVAL;
349 }
350 
351 static int tb_lc_dp_sink_available(struct tb_switch *sw, int sink)
352 {
353 	u32 val, alloc;
354 	int ret;
355 
356 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
357 			 sw->cap_lc + TB_LC_SNK_ALLOCATION, 1);
358 	if (ret)
359 		return ret;
360 
361 	/*
362 	 * Sink is available for CM/SW to use if the allocation valie is
363 	 * either 0 or 1.
364 	 */
365 	if (!sink) {
366 		alloc = val & TB_LC_SNK_ALLOCATION_SNK0_MASK;
367 		if (!alloc || alloc == TB_LC_SNK_ALLOCATION_SNK0_CM)
368 			return 0;
369 	} else {
370 		alloc = (val & TB_LC_SNK_ALLOCATION_SNK1_MASK) >>
371 			TB_LC_SNK_ALLOCATION_SNK1_SHIFT;
372 		if (!alloc || alloc == TB_LC_SNK_ALLOCATION_SNK1_CM)
373 			return 0;
374 	}
375 
376 	return -EBUSY;
377 }
378 
379 /**
380  * tb_lc_dp_sink_query() - Is DP sink available for DP IN port
381  * @sw: Switch whose DP sink is queried
382  * @in: DP IN port to check
383  *
384  * Queries through LC SNK_ALLOCATION registers whether DP sink is available
385  * for the given DP IN port or not.
386  */
387 bool tb_lc_dp_sink_query(struct tb_switch *sw, struct tb_port *in)
388 {
389 	int sink;
390 
391 	/*
392 	 * For older generations sink is always available as there is no
393 	 * allocation mechanism.
394 	 */
395 	if (sw->generation < 3)
396 		return true;
397 
398 	sink = tb_lc_dp_sink_from_port(sw, in);
399 	if (sink < 0)
400 		return false;
401 
402 	return !tb_lc_dp_sink_available(sw, sink);
403 }
404 
405 /**
406  * tb_lc_dp_sink_alloc() - Allocate DP sink
407  * @sw: Switch whose DP sink is allocated
408  * @in: DP IN port the DP sink is allocated for
409  *
410  * Allocate DP sink for @in via LC SNK_ALLOCATION registers. If the
411  * resource is available and allocation is successful returns %0. In all
412  * other cases returs negative errno. In particular %-EBUSY is returned if
413  * the resource was not available.
414  */
415 int tb_lc_dp_sink_alloc(struct tb_switch *sw, struct tb_port *in)
416 {
417 	int ret, sink;
418 	u32 val;
419 
420 	if (sw->generation < 3)
421 		return 0;
422 
423 	sink = tb_lc_dp_sink_from_port(sw, in);
424 	if (sink < 0)
425 		return sink;
426 
427 	ret = tb_lc_dp_sink_available(sw, sink);
428 	if (ret)
429 		return ret;
430 
431 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
432 			 sw->cap_lc + TB_LC_SNK_ALLOCATION, 1);
433 	if (ret)
434 		return ret;
435 
436 	if (!sink) {
437 		val &= ~TB_LC_SNK_ALLOCATION_SNK0_MASK;
438 		val |= TB_LC_SNK_ALLOCATION_SNK0_CM;
439 	} else {
440 		val &= ~TB_LC_SNK_ALLOCATION_SNK1_MASK;
441 		val |= TB_LC_SNK_ALLOCATION_SNK1_CM <<
442 			TB_LC_SNK_ALLOCATION_SNK1_SHIFT;
443 	}
444 
445 	ret = tb_sw_write(sw, &val, TB_CFG_SWITCH,
446 			  sw->cap_lc + TB_LC_SNK_ALLOCATION, 1);
447 
448 	if (ret)
449 		return ret;
450 
451 	tb_port_dbg(in, "sink %d allocated\n", sink);
452 	return 0;
453 }
454 
455 /**
456  * tb_lc_dp_sink_dealloc() - De-allocate DP sink
457  * @sw: Switch whose DP sink is de-allocated
458  * @in: DP IN port whose DP sink is de-allocated
459  *
460  * De-allocate DP sink from @in using LC SNK_ALLOCATION registers.
461  */
462 int tb_lc_dp_sink_dealloc(struct tb_switch *sw, struct tb_port *in)
463 {
464 	int ret, sink;
465 	u32 val;
466 
467 	if (sw->generation < 3)
468 		return 0;
469 
470 	sink = tb_lc_dp_sink_from_port(sw, in);
471 	if (sink < 0)
472 		return sink;
473 
474 	/* Needs to be owned by CM/SW */
475 	ret = tb_lc_dp_sink_available(sw, sink);
476 	if (ret)
477 		return ret;
478 
479 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
480 			 sw->cap_lc + TB_LC_SNK_ALLOCATION, 1);
481 	if (ret)
482 		return ret;
483 
484 	if (!sink)
485 		val &= ~TB_LC_SNK_ALLOCATION_SNK0_MASK;
486 	else
487 		val &= ~TB_LC_SNK_ALLOCATION_SNK1_MASK;
488 
489 	ret = tb_sw_write(sw, &val, TB_CFG_SWITCH,
490 			  sw->cap_lc + TB_LC_SNK_ALLOCATION, 1);
491 	if (ret)
492 		return ret;
493 
494 	tb_port_dbg(in, "sink %d de-allocated\n", sink);
495 	return 0;
496 }
497 
498 /**
499  * tb_lc_force_power() - Forces LC to be powered on
500  * @sw: Thunderbolt switch
501  *
502  * This is useful to let authentication cycle pass even without
503  * a Thunderbolt link present.
504  */
505 int tb_lc_force_power(struct tb_switch *sw)
506 {
507 	u32 in = 0xffff;
508 
509 	return tb_sw_write(sw, &in, TB_CFG_SWITCH, TB_LC_POWER, 1);
510 }
511