1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * USB Typec-C DisplayPort Alternate Mode driver
4 *
5 * Copyright (C) 2018 Intel Corporation
6 * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
7 *
8 * DisplayPort is trademark of VESA (www.vesa.org)
9 */
10
11 #include <linux/delay.h>
12 #include <linux/mutex.h>
13 #include <linux/module.h>
14 #include <linux/property.h>
15 #include <linux/usb/pd_vdo.h>
16 #include <linux/usb/typec_dp.h>
17 #include <drm/drm_connector.h>
18 #include "displayport.h"
19
20 #define DP_HEADER(_dp, ver, cmd) (VDO((_dp)->alt->svid, 1, ver, cmd) \
21 | VDO_OPOS(USB_TYPEC_DP_MODE))
22
23 enum {
24 DP_CONF_USB,
25 DP_CONF_DFP_D,
26 DP_CONF_UFP_D,
27 DP_CONF_DUAL_D,
28 };
29
30 /* Pin assignments that use USB3.1 Gen2 signaling to carry DP protocol */
31 #define DP_PIN_ASSIGN_GEN2_BR_MASK (BIT(DP_PIN_ASSIGN_A) | \
32 BIT(DP_PIN_ASSIGN_B))
33
34 /* Pin assignments that use DP v1.3 signaling to carry DP protocol */
35 #define DP_PIN_ASSIGN_DP_BR_MASK (BIT(DP_PIN_ASSIGN_C) | \
36 BIT(DP_PIN_ASSIGN_D) | \
37 BIT(DP_PIN_ASSIGN_E) | \
38 BIT(DP_PIN_ASSIGN_F))
39
40 /* DP only pin assignments */
41 #define DP_PIN_ASSIGN_DP_ONLY_MASK (BIT(DP_PIN_ASSIGN_A) | \
42 BIT(DP_PIN_ASSIGN_C) | \
43 BIT(DP_PIN_ASSIGN_E))
44
45 /* Pin assignments where one channel is for USB */
46 #define DP_PIN_ASSIGN_MULTI_FUNC_MASK (BIT(DP_PIN_ASSIGN_B) | \
47 BIT(DP_PIN_ASSIGN_D) | \
48 BIT(DP_PIN_ASSIGN_F))
49
50 enum dp_state {
51 DP_STATE_IDLE,
52 DP_STATE_ENTER,
53 DP_STATE_UPDATE,
54 DP_STATE_CONFIGURE,
55 DP_STATE_EXIT,
56 };
57
58 struct dp_altmode {
59 struct typec_displayport_data data;
60
61 enum dp_state state;
62 bool hpd;
63
64 struct mutex lock; /* device lock */
65 struct work_struct work;
66 struct typec_altmode *alt;
67 const struct typec_altmode *port;
68 struct fwnode_handle *connector_fwnode;
69 };
70
dp_altmode_notify(struct dp_altmode * dp)71 static int dp_altmode_notify(struct dp_altmode *dp)
72 {
73 unsigned long conf;
74 u8 state;
75
76 if (dp->data.conf) {
77 state = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf));
78 conf = TYPEC_MODAL_STATE(state);
79 } else {
80 conf = TYPEC_STATE_USB;
81 }
82
83 return typec_altmode_notify(dp->alt, conf, &dp->data);
84 }
85
dp_altmode_configure(struct dp_altmode * dp,u8 con)86 static int dp_altmode_configure(struct dp_altmode *dp, u8 con)
87 {
88 u32 conf = DP_CONF_SIGNALING_DP; /* Only DP signaling supported */
89 u8 pin_assign = 0;
90
91 switch (con) {
92 case DP_STATUS_CON_DISABLED:
93 return 0;
94 case DP_STATUS_CON_DFP_D:
95 conf |= DP_CONF_UFP_U_AS_DFP_D;
96 pin_assign = DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo) &
97 DP_CAP_DFP_D_PIN_ASSIGN(dp->port->vdo);
98 break;
99 case DP_STATUS_CON_UFP_D:
100 case DP_STATUS_CON_BOTH: /* NOTE: First acting as DP source */
101 conf |= DP_CONF_UFP_U_AS_UFP_D;
102 pin_assign = DP_CAP_PIN_ASSIGN_UFP_D(dp->alt->vdo) &
103 DP_CAP_PIN_ASSIGN_DFP_D(dp->port->vdo);
104 break;
105 default:
106 break;
107 }
108
109 /* Determining the initial pin assignment. */
110 if (!DP_CONF_GET_PIN_ASSIGN(dp->data.conf)) {
111 /* Is USB together with DP preferred */
112 if (dp->data.status & DP_STATUS_PREFER_MULTI_FUNC &&
113 pin_assign & DP_PIN_ASSIGN_MULTI_FUNC_MASK)
114 pin_assign &= DP_PIN_ASSIGN_MULTI_FUNC_MASK;
115 else if (pin_assign & DP_PIN_ASSIGN_DP_ONLY_MASK)
116 pin_assign &= DP_PIN_ASSIGN_DP_ONLY_MASK;
117
118 if (!pin_assign)
119 return -EINVAL;
120
121 conf |= DP_CONF_SET_PIN_ASSIGN(pin_assign);
122 }
123
124 dp->data.conf = conf;
125
126 return 0;
127 }
128
dp_altmode_status_update(struct dp_altmode * dp)129 static int dp_altmode_status_update(struct dp_altmode *dp)
130 {
131 bool configured = !!DP_CONF_GET_PIN_ASSIGN(dp->data.conf);
132 bool hpd = !!(dp->data.status & DP_STATUS_HPD_STATE);
133 u8 con = DP_STATUS_CONNECTION(dp->data.status);
134 int ret = 0;
135
136 if (configured && (dp->data.status & DP_STATUS_SWITCH_TO_USB)) {
137 dp->data.conf = 0;
138 dp->state = DP_STATE_CONFIGURE;
139 } else if (dp->data.status & DP_STATUS_EXIT_DP_MODE) {
140 dp->state = DP_STATE_EXIT;
141 } else if (!(con & DP_CONF_CURRENTLY(dp->data.conf))) {
142 ret = dp_altmode_configure(dp, con);
143 if (!ret)
144 dp->state = DP_STATE_CONFIGURE;
145 } else {
146 if (dp->hpd != hpd) {
147 drm_connector_oob_hotplug_event(dp->connector_fwnode);
148 dp->hpd = hpd;
149 sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
150 }
151 }
152
153 return ret;
154 }
155
dp_altmode_configured(struct dp_altmode * dp)156 static int dp_altmode_configured(struct dp_altmode *dp)
157 {
158 sysfs_notify(&dp->alt->dev.kobj, "displayport", "configuration");
159 sysfs_notify(&dp->alt->dev.kobj, "displayport", "pin_assignment");
160
161 return dp_altmode_notify(dp);
162 }
163
dp_altmode_configure_vdm(struct dp_altmode * dp,u32 conf)164 static int dp_altmode_configure_vdm(struct dp_altmode *dp, u32 conf)
165 {
166 int svdm_version = typec_altmode_get_svdm_version(dp->alt);
167 u32 header;
168 int ret;
169
170 if (svdm_version < 0)
171 return svdm_version;
172
173 header = DP_HEADER(dp, svdm_version, DP_CMD_CONFIGURE);
174 ret = typec_altmode_notify(dp->alt, TYPEC_STATE_SAFE, &dp->data);
175 if (ret) {
176 dev_err(&dp->alt->dev,
177 "unable to put to connector to safe mode\n");
178 return ret;
179 }
180
181 ret = typec_altmode_vdm(dp->alt, header, &conf, 2);
182 if (ret)
183 dp_altmode_notify(dp);
184
185 return ret;
186 }
187
dp_altmode_work(struct work_struct * work)188 static void dp_altmode_work(struct work_struct *work)
189 {
190 struct dp_altmode *dp = container_of(work, struct dp_altmode, work);
191 int svdm_version;
192 u32 header;
193 u32 vdo;
194 int ret;
195
196 mutex_lock(&dp->lock);
197
198 switch (dp->state) {
199 case DP_STATE_ENTER:
200 ret = typec_altmode_enter(dp->alt, NULL);
201 if (ret && ret != -EBUSY)
202 dev_err(&dp->alt->dev, "failed to enter mode\n");
203 break;
204 case DP_STATE_UPDATE:
205 svdm_version = typec_altmode_get_svdm_version(dp->alt);
206 if (svdm_version < 0)
207 break;
208 header = DP_HEADER(dp, svdm_version, DP_CMD_STATUS_UPDATE);
209 vdo = 1;
210 ret = typec_altmode_vdm(dp->alt, header, &vdo, 2);
211 if (ret)
212 dev_err(&dp->alt->dev,
213 "unable to send Status Update command (%d)\n",
214 ret);
215 break;
216 case DP_STATE_CONFIGURE:
217 ret = dp_altmode_configure_vdm(dp, dp->data.conf);
218 if (ret)
219 dev_err(&dp->alt->dev,
220 "unable to send Configure command (%d)\n", ret);
221 break;
222 case DP_STATE_EXIT:
223 if (typec_altmode_exit(dp->alt))
224 dev_err(&dp->alt->dev, "Exit Mode Failed!\n");
225 break;
226 default:
227 break;
228 }
229
230 dp->state = DP_STATE_IDLE;
231
232 mutex_unlock(&dp->lock);
233 }
234
dp_altmode_attention(struct typec_altmode * alt,const u32 vdo)235 static void dp_altmode_attention(struct typec_altmode *alt, const u32 vdo)
236 {
237 struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
238 u8 old_state;
239
240 mutex_lock(&dp->lock);
241
242 old_state = dp->state;
243 dp->data.status = vdo;
244
245 if (old_state != DP_STATE_IDLE)
246 dev_warn(&alt->dev, "ATTENTION while processing state %d\n",
247 old_state);
248
249 if (dp_altmode_status_update(dp))
250 dev_warn(&alt->dev, "%s: status update failed\n", __func__);
251
252 if (dp_altmode_notify(dp))
253 dev_err(&alt->dev, "%s: notification failed\n", __func__);
254
255 if (old_state == DP_STATE_IDLE && dp->state != DP_STATE_IDLE)
256 schedule_work(&dp->work);
257
258 mutex_unlock(&dp->lock);
259 }
260
dp_altmode_vdm(struct typec_altmode * alt,const u32 hdr,const u32 * vdo,int count)261 static int dp_altmode_vdm(struct typec_altmode *alt,
262 const u32 hdr, const u32 *vdo, int count)
263 {
264 struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
265 int cmd_type = PD_VDO_CMDT(hdr);
266 int cmd = PD_VDO_CMD(hdr);
267 int ret = 0;
268
269 mutex_lock(&dp->lock);
270
271 if (dp->state != DP_STATE_IDLE) {
272 ret = -EBUSY;
273 goto err_unlock;
274 }
275
276 switch (cmd_type) {
277 case CMDT_RSP_ACK:
278 switch (cmd) {
279 case CMD_ENTER_MODE:
280 typec_altmode_update_active(alt, true);
281 dp->state = DP_STATE_UPDATE;
282 break;
283 case CMD_EXIT_MODE:
284 typec_altmode_update_active(alt, false);
285 dp->data.status = 0;
286 dp->data.conf = 0;
287 break;
288 case DP_CMD_STATUS_UPDATE:
289 dp->data.status = *vdo;
290 ret = dp_altmode_status_update(dp);
291 break;
292 case DP_CMD_CONFIGURE:
293 ret = dp_altmode_configured(dp);
294 break;
295 default:
296 break;
297 }
298 break;
299 case CMDT_RSP_NAK:
300 switch (cmd) {
301 case DP_CMD_CONFIGURE:
302 dp->data.conf = 0;
303 ret = dp_altmode_configured(dp);
304 break;
305 default:
306 break;
307 }
308 break;
309 default:
310 break;
311 }
312
313 if (dp->state != DP_STATE_IDLE)
314 schedule_work(&dp->work);
315
316 err_unlock:
317 mutex_unlock(&dp->lock);
318 return ret;
319 }
320
dp_altmode_activate(struct typec_altmode * alt,int activate)321 static int dp_altmode_activate(struct typec_altmode *alt, int activate)
322 {
323 return activate ? typec_altmode_enter(alt, NULL) :
324 typec_altmode_exit(alt);
325 }
326
327 static const struct typec_altmode_ops dp_altmode_ops = {
328 .attention = dp_altmode_attention,
329 .vdm = dp_altmode_vdm,
330 .activate = dp_altmode_activate,
331 };
332
333 static const char * const configurations[] = {
334 [DP_CONF_USB] = "USB",
335 [DP_CONF_DFP_D] = "source",
336 [DP_CONF_UFP_D] = "sink",
337 };
338
339 static ssize_t
configuration_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)340 configuration_store(struct device *dev, struct device_attribute *attr,
341 const char *buf, size_t size)
342 {
343 struct dp_altmode *dp = dev_get_drvdata(dev);
344 u32 conf;
345 u32 cap;
346 int con;
347 int ret = 0;
348
349 con = sysfs_match_string(configurations, buf);
350 if (con < 0)
351 return con;
352
353 mutex_lock(&dp->lock);
354
355 if (dp->state != DP_STATE_IDLE) {
356 ret = -EBUSY;
357 goto err_unlock;
358 }
359
360 cap = DP_CAP_CAPABILITY(dp->alt->vdo);
361
362 if ((con == DP_CONF_DFP_D && !(cap & DP_CAP_DFP_D)) ||
363 (con == DP_CONF_UFP_D && !(cap & DP_CAP_UFP_D))) {
364 ret = -EINVAL;
365 goto err_unlock;
366 }
367
368 conf = dp->data.conf & ~DP_CONF_DUAL_D;
369 conf |= con;
370
371 if (dp->alt->active) {
372 ret = dp_altmode_configure_vdm(dp, conf);
373 if (ret)
374 goto err_unlock;
375 }
376
377 dp->data.conf = conf;
378
379 err_unlock:
380 mutex_unlock(&dp->lock);
381
382 return ret ? ret : size;
383 }
384
configuration_show(struct device * dev,struct device_attribute * attr,char * buf)385 static ssize_t configuration_show(struct device *dev,
386 struct device_attribute *attr, char *buf)
387 {
388 struct dp_altmode *dp = dev_get_drvdata(dev);
389 int len;
390 u8 cap;
391 u8 cur;
392 int i;
393
394 mutex_lock(&dp->lock);
395
396 cap = DP_CAP_CAPABILITY(dp->alt->vdo);
397 cur = DP_CONF_CURRENTLY(dp->data.conf);
398
399 len = sprintf(buf, "%s ", cur ? "USB" : "[USB]");
400
401 for (i = 1; i < ARRAY_SIZE(configurations); i++) {
402 if (i == cur)
403 len += sprintf(buf + len, "[%s] ", configurations[i]);
404 else if ((i == DP_CONF_DFP_D && cap & DP_CAP_DFP_D) ||
405 (i == DP_CONF_UFP_D && cap & DP_CAP_UFP_D))
406 len += sprintf(buf + len, "%s ", configurations[i]);
407 }
408
409 mutex_unlock(&dp->lock);
410
411 buf[len - 1] = '\n';
412 return len;
413 }
414 static DEVICE_ATTR_RW(configuration);
415
416 static const char * const pin_assignments[] = {
417 [DP_PIN_ASSIGN_A] = "A",
418 [DP_PIN_ASSIGN_B] = "B",
419 [DP_PIN_ASSIGN_C] = "C",
420 [DP_PIN_ASSIGN_D] = "D",
421 [DP_PIN_ASSIGN_E] = "E",
422 [DP_PIN_ASSIGN_F] = "F",
423 };
424
425 /*
426 * Helper function to extract a peripheral's currently supported
427 * Pin Assignments from its DisplayPort alternate mode state.
428 */
get_current_pin_assignments(struct dp_altmode * dp)429 static u8 get_current_pin_assignments(struct dp_altmode *dp)
430 {
431 if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_UFP_U_AS_DFP_D)
432 return DP_CAP_PIN_ASSIGN_DFP_D(dp->alt->vdo);
433 else
434 return DP_CAP_PIN_ASSIGN_UFP_D(dp->alt->vdo);
435 }
436
437 static ssize_t
pin_assignment_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)438 pin_assignment_store(struct device *dev, struct device_attribute *attr,
439 const char *buf, size_t size)
440 {
441 struct dp_altmode *dp = dev_get_drvdata(dev);
442 u8 assignments;
443 u32 conf;
444 int ret;
445
446 ret = sysfs_match_string(pin_assignments, buf);
447 if (ret < 0)
448 return ret;
449
450 conf = DP_CONF_SET_PIN_ASSIGN(BIT(ret));
451 ret = 0;
452
453 mutex_lock(&dp->lock);
454
455 if (conf & dp->data.conf)
456 goto out_unlock;
457
458 if (dp->state != DP_STATE_IDLE) {
459 ret = -EBUSY;
460 goto out_unlock;
461 }
462
463 assignments = get_current_pin_assignments(dp);
464
465 if (!(DP_CONF_GET_PIN_ASSIGN(conf) & assignments)) {
466 ret = -EINVAL;
467 goto out_unlock;
468 }
469
470 conf |= dp->data.conf & ~DP_CONF_PIN_ASSIGNEMENT_MASK;
471
472 /* Only send Configure command if a configuration has been set */
473 if (dp->alt->active && DP_CONF_CURRENTLY(dp->data.conf)) {
474 ret = dp_altmode_configure_vdm(dp, conf);
475 if (ret)
476 goto out_unlock;
477 }
478
479 dp->data.conf = conf;
480
481 out_unlock:
482 mutex_unlock(&dp->lock);
483
484 return ret ? ret : size;
485 }
486
pin_assignment_show(struct device * dev,struct device_attribute * attr,char * buf)487 static ssize_t pin_assignment_show(struct device *dev,
488 struct device_attribute *attr, char *buf)
489 {
490 struct dp_altmode *dp = dev_get_drvdata(dev);
491 u8 assignments;
492 int len = 0;
493 u8 cur;
494 int i;
495
496 mutex_lock(&dp->lock);
497
498 cur = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf));
499
500 assignments = get_current_pin_assignments(dp);
501
502 for (i = 0; assignments; assignments >>= 1, i++) {
503 if (assignments & 1) {
504 if (i == cur)
505 len += sprintf(buf + len, "[%s] ",
506 pin_assignments[i]);
507 else
508 len += sprintf(buf + len, "%s ",
509 pin_assignments[i]);
510 }
511 }
512
513 mutex_unlock(&dp->lock);
514
515 buf[len - 1] = '\n';
516 return len;
517 }
518 static DEVICE_ATTR_RW(pin_assignment);
519
hpd_show(struct device * dev,struct device_attribute * attr,char * buf)520 static ssize_t hpd_show(struct device *dev, struct device_attribute *attr, char *buf)
521 {
522 struct dp_altmode *dp = dev_get_drvdata(dev);
523
524 return sysfs_emit(buf, "%d\n", dp->hpd);
525 }
526 static DEVICE_ATTR_RO(hpd);
527
528 static struct attribute *dp_altmode_attrs[] = {
529 &dev_attr_configuration.attr,
530 &dev_attr_pin_assignment.attr,
531 &dev_attr_hpd.attr,
532 NULL
533 };
534
535 static const struct attribute_group dp_altmode_group = {
536 .name = "displayport",
537 .attrs = dp_altmode_attrs,
538 };
539
dp_altmode_probe(struct typec_altmode * alt)540 int dp_altmode_probe(struct typec_altmode *alt)
541 {
542 const struct typec_altmode *port = typec_altmode_get_partner(alt);
543 struct fwnode_handle *fwnode;
544 struct dp_altmode *dp;
545 int ret;
546
547 /* FIXME: Port can only be DFP_U. */
548
549 /* Make sure we have compatiple pin configurations */
550 if (!(DP_CAP_PIN_ASSIGN_DFP_D(port->vdo) &
551 DP_CAP_PIN_ASSIGN_UFP_D(alt->vdo)) &&
552 !(DP_CAP_PIN_ASSIGN_UFP_D(port->vdo) &
553 DP_CAP_PIN_ASSIGN_DFP_D(alt->vdo)))
554 return -ENODEV;
555
556 ret = sysfs_create_group(&alt->dev.kobj, &dp_altmode_group);
557 if (ret)
558 return ret;
559
560 dp = devm_kzalloc(&alt->dev, sizeof(*dp), GFP_KERNEL);
561 if (!dp)
562 return -ENOMEM;
563
564 INIT_WORK(&dp->work, dp_altmode_work);
565 mutex_init(&dp->lock);
566 dp->port = port;
567 dp->alt = alt;
568
569 alt->desc = "DisplayPort";
570 alt->ops = &dp_altmode_ops;
571
572 fwnode = dev_fwnode(alt->dev.parent->parent); /* typec_port fwnode */
573 dp->connector_fwnode = fwnode_find_reference(fwnode, "displayport", 0);
574 if (IS_ERR(dp->connector_fwnode))
575 dp->connector_fwnode = NULL;
576
577 typec_altmode_set_drvdata(alt, dp);
578
579 dp->state = DP_STATE_ENTER;
580 schedule_work(&dp->work);
581
582 return 0;
583 }
584 EXPORT_SYMBOL_GPL(dp_altmode_probe);
585
dp_altmode_remove(struct typec_altmode * alt)586 void dp_altmode_remove(struct typec_altmode *alt)
587 {
588 struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
589
590 sysfs_remove_group(&alt->dev.kobj, &dp_altmode_group);
591 cancel_work_sync(&dp->work);
592
593 if (dp->connector_fwnode) {
594 if (dp->hpd)
595 drm_connector_oob_hotplug_event(dp->connector_fwnode);
596
597 fwnode_handle_put(dp->connector_fwnode);
598 }
599 }
600 EXPORT_SYMBOL_GPL(dp_altmode_remove);
601
602 static const struct typec_device_id dp_typec_id[] = {
603 { USB_TYPEC_DP_SID, USB_TYPEC_DP_MODE },
604 { },
605 };
606 MODULE_DEVICE_TABLE(typec, dp_typec_id);
607
608 static struct typec_altmode_driver dp_altmode_driver = {
609 .id_table = dp_typec_id,
610 .probe = dp_altmode_probe,
611 .remove = dp_altmode_remove,
612 .driver = {
613 .name = "typec_displayport",
614 .owner = THIS_MODULE,
615 },
616 };
617 module_typec_altmode_driver(dp_altmode_driver);
618
619 MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
620 MODULE_LICENSE("GPL v2");
621 MODULE_DESCRIPTION("DisplayPort Alternate Mode");
622