xref: /linux/drivers/thunderbolt/lc.c (revision 413d6ed3eac387a2876893c337174f0c5b99d01d)
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_WOP |
212 		  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 
221 	return tb_sw_write(sw, &ctrl, TB_CFG_SWITCH, offset + TB_LC_SX_CTRL, 1);
222 }
223 
224 /**
225  * tb_lc_set_wake() - Enable/disable wake
226  * @sw: Switch whose wakes to configure
227  * @flags: Wakeup flags (%0 to disable)
228  *
229  * For each LC sets wake bits accordingly.
230  */
231 int tb_lc_set_wake(struct tb_switch *sw, unsigned int flags)
232 {
233 	int start, size, nlc, ret, i;
234 	u32 desc;
235 
236 	if (sw->generation < 2)
237 		return 0;
238 
239 	if (!tb_route(sw))
240 		return 0;
241 
242 	ret = read_lc_desc(sw, &desc);
243 	if (ret)
244 		return ret;
245 
246 	/* Figure out number of link controllers */
247 	nlc = desc & TB_LC_DESC_NLC_MASK;
248 	start = (desc & TB_LC_DESC_SIZE_MASK) >> TB_LC_DESC_SIZE_SHIFT;
249 	size = (desc & TB_LC_DESC_PORT_SIZE_MASK) >> TB_LC_DESC_PORT_SIZE_SHIFT;
250 
251 	/* For each link controller set sleep bit */
252 	for (i = 0; i < nlc; i++) {
253 		unsigned int offset = sw->cap_lc + start + i * size;
254 
255 		ret = tb_lc_set_wake_one(sw, offset, flags);
256 		if (ret)
257 			return ret;
258 	}
259 
260 	return 0;
261 }
262 
263 /**
264  * tb_lc_set_sleep() - Inform LC that the switch is going to sleep
265  * @sw: Switch to set sleep
266  *
267  * Let the switch link controllers know that the switch is going to
268  * sleep.
269  */
270 int tb_lc_set_sleep(struct tb_switch *sw)
271 {
272 	int start, size, nlc, ret, i;
273 	u32 desc;
274 
275 	if (sw->generation < 2)
276 		return 0;
277 
278 	ret = read_lc_desc(sw, &desc);
279 	if (ret)
280 		return ret;
281 
282 	/* Figure out number of link controllers */
283 	nlc = desc & TB_LC_DESC_NLC_MASK;
284 	start = (desc & TB_LC_DESC_SIZE_MASK) >> TB_LC_DESC_SIZE_SHIFT;
285 	size = (desc & TB_LC_DESC_PORT_SIZE_MASK) >> TB_LC_DESC_PORT_SIZE_SHIFT;
286 
287 	/* For each link controller set sleep bit */
288 	for (i = 0; i < nlc; i++) {
289 		unsigned int offset = sw->cap_lc + start + i * size;
290 		u32 ctrl;
291 
292 		ret = tb_sw_read(sw, &ctrl, TB_CFG_SWITCH,
293 				 offset + TB_LC_SX_CTRL, 1);
294 		if (ret)
295 			return ret;
296 
297 		ctrl |= TB_LC_SX_CTRL_SLP;
298 		ret = tb_sw_write(sw, &ctrl, TB_CFG_SWITCH,
299 				  offset + TB_LC_SX_CTRL, 1);
300 		if (ret)
301 			return ret;
302 	}
303 
304 	return 0;
305 }
306 
307 /**
308  * tb_lc_lane_bonding_possible() - Is lane bonding possible towards switch
309  * @sw: Switch to check
310  *
311  * Checks whether conditions for lane bonding from parent to @sw are
312  * possible.
313  */
314 bool tb_lc_lane_bonding_possible(struct tb_switch *sw)
315 {
316 	struct tb_port *up;
317 	int cap, ret;
318 	u32 val;
319 
320 	if (sw->generation < 2)
321 		return false;
322 
323 	up = tb_upstream_port(sw);
324 	cap = find_port_lc_cap(up);
325 	if (cap < 0)
326 		return false;
327 
328 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, cap + TB_LC_PORT_ATTR, 1);
329 	if (ret)
330 		return false;
331 
332 	return !!(val & TB_LC_PORT_ATTR_BE);
333 }
334 
335 static int tb_lc_dp_sink_from_port(const struct tb_switch *sw,
336 				   struct tb_port *in)
337 {
338 	struct tb_port *port;
339 
340 	/* The first DP IN port is sink 0 and second is sink 1 */
341 	tb_switch_for_each_port(sw, port) {
342 		if (tb_port_is_dpin(port))
343 			return in != port;
344 	}
345 
346 	return -EINVAL;
347 }
348 
349 static int tb_lc_dp_sink_available(struct tb_switch *sw, int sink)
350 {
351 	u32 val, alloc;
352 	int ret;
353 
354 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
355 			 sw->cap_lc + TB_LC_SNK_ALLOCATION, 1);
356 	if (ret)
357 		return ret;
358 
359 	/*
360 	 * Sink is available for CM/SW to use if the allocation valie is
361 	 * either 0 or 1.
362 	 */
363 	if (!sink) {
364 		alloc = val & TB_LC_SNK_ALLOCATION_SNK0_MASK;
365 		if (!alloc || alloc == TB_LC_SNK_ALLOCATION_SNK0_CM)
366 			return 0;
367 	} else {
368 		alloc = (val & TB_LC_SNK_ALLOCATION_SNK1_MASK) >>
369 			TB_LC_SNK_ALLOCATION_SNK1_SHIFT;
370 		if (!alloc || alloc == TB_LC_SNK_ALLOCATION_SNK1_CM)
371 			return 0;
372 	}
373 
374 	return -EBUSY;
375 }
376 
377 /**
378  * tb_lc_dp_sink_query() - Is DP sink available for DP IN port
379  * @sw: Switch whose DP sink is queried
380  * @in: DP IN port to check
381  *
382  * Queries through LC SNK_ALLOCATION registers whether DP sink is available
383  * for the given DP IN port or not.
384  */
385 bool tb_lc_dp_sink_query(struct tb_switch *sw, struct tb_port *in)
386 {
387 	int sink;
388 
389 	/*
390 	 * For older generations sink is always available as there is no
391 	 * allocation mechanism.
392 	 */
393 	if (sw->generation < 3)
394 		return true;
395 
396 	sink = tb_lc_dp_sink_from_port(sw, in);
397 	if (sink < 0)
398 		return false;
399 
400 	return !tb_lc_dp_sink_available(sw, sink);
401 }
402 
403 /**
404  * tb_lc_dp_sink_alloc() - Allocate DP sink
405  * @sw: Switch whose DP sink is allocated
406  * @in: DP IN port the DP sink is allocated for
407  *
408  * Allocate DP sink for @in via LC SNK_ALLOCATION registers. If the
409  * resource is available and allocation is successful returns %0. In all
410  * other cases returs negative errno. In particular %-EBUSY is returned if
411  * the resource was not available.
412  */
413 int tb_lc_dp_sink_alloc(struct tb_switch *sw, struct tb_port *in)
414 {
415 	int ret, sink;
416 	u32 val;
417 
418 	if (sw->generation < 3)
419 		return 0;
420 
421 	sink = tb_lc_dp_sink_from_port(sw, in);
422 	if (sink < 0)
423 		return sink;
424 
425 	ret = tb_lc_dp_sink_available(sw, sink);
426 	if (ret)
427 		return ret;
428 
429 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
430 			 sw->cap_lc + TB_LC_SNK_ALLOCATION, 1);
431 	if (ret)
432 		return ret;
433 
434 	if (!sink) {
435 		val &= ~TB_LC_SNK_ALLOCATION_SNK0_MASK;
436 		val |= TB_LC_SNK_ALLOCATION_SNK0_CM;
437 	} else {
438 		val &= ~TB_LC_SNK_ALLOCATION_SNK1_MASK;
439 		val |= TB_LC_SNK_ALLOCATION_SNK1_CM <<
440 			TB_LC_SNK_ALLOCATION_SNK1_SHIFT;
441 	}
442 
443 	ret = tb_sw_write(sw, &val, TB_CFG_SWITCH,
444 			  sw->cap_lc + TB_LC_SNK_ALLOCATION, 1);
445 
446 	if (ret)
447 		return ret;
448 
449 	tb_port_dbg(in, "sink %d allocated\n", sink);
450 	return 0;
451 }
452 
453 /**
454  * tb_lc_dp_sink_dealloc() - De-allocate DP sink
455  * @sw: Switch whose DP sink is de-allocated
456  * @in: DP IN port whose DP sink is de-allocated
457  *
458  * De-allocate DP sink from @in using LC SNK_ALLOCATION registers.
459  */
460 int tb_lc_dp_sink_dealloc(struct tb_switch *sw, struct tb_port *in)
461 {
462 	int ret, sink;
463 	u32 val;
464 
465 	if (sw->generation < 3)
466 		return 0;
467 
468 	sink = tb_lc_dp_sink_from_port(sw, in);
469 	if (sink < 0)
470 		return sink;
471 
472 	/* Needs to be owned by CM/SW */
473 	ret = tb_lc_dp_sink_available(sw, sink);
474 	if (ret)
475 		return ret;
476 
477 	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
478 			 sw->cap_lc + TB_LC_SNK_ALLOCATION, 1);
479 	if (ret)
480 		return ret;
481 
482 	if (!sink)
483 		val &= ~TB_LC_SNK_ALLOCATION_SNK0_MASK;
484 	else
485 		val &= ~TB_LC_SNK_ALLOCATION_SNK1_MASK;
486 
487 	ret = tb_sw_write(sw, &val, TB_CFG_SWITCH,
488 			  sw->cap_lc + TB_LC_SNK_ALLOCATION, 1);
489 	if (ret)
490 		return ret;
491 
492 	tb_port_dbg(in, "sink %d de-allocated\n", sink);
493 	return 0;
494 }
495 
496 /**
497  * tb_lc_force_power() - Forces LC to be powered on
498  * @sw: Thunderbolt switch
499  *
500  * This is useful to let authentication cycle pass even without
501  * a Thunderbolt link present.
502  */
503 int tb_lc_force_power(struct tb_switch *sw)
504 {
505 	u32 in = 0xffff;
506 
507 	return tb_sw_write(sw, &in, TB_CFG_SWITCH, TB_LC_POWER, 1);
508 }
509