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 bool pending_hpd;
64
65 struct mutex lock; /* device lock */
66 struct work_struct work;
67 struct typec_altmode *alt;
68 const struct typec_altmode *port;
69 struct fwnode_handle *connector_fwnode;
70 };
71
dp_altmode_notify(struct dp_altmode * dp)72 static int dp_altmode_notify(struct dp_altmode *dp)
73 {
74 unsigned long conf;
75 u8 state;
76
77 if (dp->data.conf) {
78 state = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf));
79 conf = TYPEC_MODAL_STATE(state);
80 } else {
81 conf = TYPEC_STATE_USB;
82 }
83
84 return typec_altmode_notify(dp->alt, conf, &dp->data);
85 }
86
dp_altmode_configure(struct dp_altmode * dp,u8 con)87 static int dp_altmode_configure(struct dp_altmode *dp, u8 con)
88 {
89 u8 pin_assign = 0;
90 u32 conf;
91
92 /* DP Signalling */
93 conf = (dp->data.conf & DP_CONF_SIGNALLING_MASK) >> DP_CONF_SIGNALLING_SHIFT;
94
95 switch (con) {
96 case DP_STATUS_CON_DISABLED:
97 return 0;
98 case DP_STATUS_CON_DFP_D:
99 conf |= DP_CONF_UFP_U_AS_DFP_D;
100 pin_assign = DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo) &
101 DP_CAP_DFP_D_PIN_ASSIGN(dp->port->vdo);
102 break;
103 case DP_STATUS_CON_UFP_D:
104 case DP_STATUS_CON_BOTH: /* NOTE: First acting as DP source */
105 conf |= DP_CONF_UFP_U_AS_UFP_D;
106 pin_assign = DP_CAP_PIN_ASSIGN_UFP_D(dp->alt->vdo) &
107 DP_CAP_PIN_ASSIGN_DFP_D(dp->port->vdo);
108 break;
109 default:
110 break;
111 }
112
113 /* Determining the initial pin assignment. */
114 if (!DP_CONF_GET_PIN_ASSIGN(dp->data.conf)) {
115 /* Is USB together with DP preferred */
116 if (dp->data.status & DP_STATUS_PREFER_MULTI_FUNC &&
117 pin_assign & DP_PIN_ASSIGN_MULTI_FUNC_MASK)
118 pin_assign &= DP_PIN_ASSIGN_MULTI_FUNC_MASK;
119 else if (pin_assign & DP_PIN_ASSIGN_DP_ONLY_MASK) {
120 pin_assign &= DP_PIN_ASSIGN_DP_ONLY_MASK;
121 /* Default to pin assign C if available */
122 if (pin_assign & BIT(DP_PIN_ASSIGN_C))
123 pin_assign = BIT(DP_PIN_ASSIGN_C);
124 }
125
126 if (!pin_assign)
127 return -EINVAL;
128
129 conf |= DP_CONF_SET_PIN_ASSIGN(pin_assign);
130 }
131
132 dp->data.conf = conf;
133
134 return 0;
135 }
136
dp_altmode_status_update(struct dp_altmode * dp)137 static int dp_altmode_status_update(struct dp_altmode *dp)
138 {
139 bool configured = !!DP_CONF_GET_PIN_ASSIGN(dp->data.conf);
140 bool hpd = !!(dp->data.status & DP_STATUS_HPD_STATE);
141 u8 con = DP_STATUS_CONNECTION(dp->data.status);
142 int ret = 0;
143
144 if (configured && (dp->data.status & DP_STATUS_SWITCH_TO_USB)) {
145 dp->data.conf = 0;
146 dp->state = DP_STATE_CONFIGURE;
147 } else if (dp->data.status & DP_STATUS_EXIT_DP_MODE) {
148 dp->state = DP_STATE_EXIT;
149 } else if (!(con & DP_CONF_CURRENTLY(dp->data.conf))) {
150 ret = dp_altmode_configure(dp, con);
151 if (!ret) {
152 dp->state = DP_STATE_CONFIGURE;
153 if (dp->hpd != hpd) {
154 dp->hpd = hpd;
155 dp->pending_hpd = true;
156 }
157 }
158 } else {
159 drm_connector_oob_hotplug_event(dp->connector_fwnode,
160 hpd ? connector_status_connected :
161 connector_status_disconnected);
162 dp->hpd = hpd;
163 sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
164 }
165
166 return ret;
167 }
168
dp_altmode_configured(struct dp_altmode * dp)169 static int dp_altmode_configured(struct dp_altmode *dp)
170 {
171 sysfs_notify(&dp->alt->dev.kobj, "displayport", "configuration");
172 sysfs_notify(&dp->alt->dev.kobj, "displayport", "pin_assignment");
173 /*
174 * If the DFP_D/UFP_D sends a change in HPD when first notifying the
175 * DisplayPort driver that it is connected, then we wait until
176 * configuration is complete to signal HPD.
177 */
178 if (dp->pending_hpd) {
179 drm_connector_oob_hotplug_event(dp->connector_fwnode,
180 connector_status_connected);
181 sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
182 dp->pending_hpd = false;
183 }
184
185 return dp_altmode_notify(dp);
186 }
187
dp_altmode_configure_vdm(struct dp_altmode * dp,u32 conf)188 static int dp_altmode_configure_vdm(struct dp_altmode *dp, u32 conf)
189 {
190 int svdm_version = typec_altmode_get_svdm_version(dp->alt);
191 u32 header;
192 int ret;
193
194 if (svdm_version < 0)
195 return svdm_version;
196
197 header = DP_HEADER(dp, svdm_version, DP_CMD_CONFIGURE);
198 ret = typec_altmode_notify(dp->alt, TYPEC_STATE_SAFE, &dp->data);
199 if (ret) {
200 dev_err(&dp->alt->dev,
201 "unable to put to connector to safe mode\n");
202 return ret;
203 }
204
205 ret = typec_altmode_vdm(dp->alt, header, &conf, 2);
206 if (ret)
207 dp_altmode_notify(dp);
208
209 return ret;
210 }
211
dp_altmode_work(struct work_struct * work)212 static void dp_altmode_work(struct work_struct *work)
213 {
214 struct dp_altmode *dp = container_of(work, struct dp_altmode, work);
215 int svdm_version;
216 u32 header;
217 u32 vdo;
218 int ret;
219
220 mutex_lock(&dp->lock);
221
222 switch (dp->state) {
223 case DP_STATE_ENTER:
224 ret = typec_altmode_enter(dp->alt, NULL);
225 if (ret && ret != -EBUSY)
226 dev_err(&dp->alt->dev, "failed to enter mode\n");
227 break;
228 case DP_STATE_UPDATE:
229 svdm_version = typec_altmode_get_svdm_version(dp->alt);
230 if (svdm_version < 0)
231 break;
232 header = DP_HEADER(dp, svdm_version, DP_CMD_STATUS_UPDATE);
233 vdo = 1;
234 ret = typec_altmode_vdm(dp->alt, header, &vdo, 2);
235 if (ret)
236 dev_err(&dp->alt->dev,
237 "unable to send Status Update command (%d)\n",
238 ret);
239 break;
240 case DP_STATE_CONFIGURE:
241 ret = dp_altmode_configure_vdm(dp, dp->data.conf);
242 if (ret)
243 dev_err(&dp->alt->dev,
244 "unable to send Configure command (%d)\n", ret);
245 break;
246 case DP_STATE_EXIT:
247 if (typec_altmode_exit(dp->alt))
248 dev_err(&dp->alt->dev, "Exit Mode Failed!\n");
249 break;
250 default:
251 break;
252 }
253
254 dp->state = DP_STATE_IDLE;
255
256 mutex_unlock(&dp->lock);
257 }
258
dp_altmode_attention(struct typec_altmode * alt,const u32 vdo)259 static void dp_altmode_attention(struct typec_altmode *alt, const u32 vdo)
260 {
261 struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
262 u8 old_state;
263
264 mutex_lock(&dp->lock);
265
266 old_state = dp->state;
267 dp->data.status = vdo;
268
269 if (old_state != DP_STATE_IDLE)
270 dev_warn(&alt->dev, "ATTENTION while processing state %d\n",
271 old_state);
272
273 if (dp_altmode_status_update(dp))
274 dev_warn(&alt->dev, "%s: status update failed\n", __func__);
275
276 if (dp_altmode_notify(dp))
277 dev_err(&alt->dev, "%s: notification failed\n", __func__);
278
279 if (old_state == DP_STATE_IDLE && dp->state != DP_STATE_IDLE)
280 schedule_work(&dp->work);
281
282 mutex_unlock(&dp->lock);
283 }
284
dp_altmode_vdm(struct typec_altmode * alt,const u32 hdr,const u32 * vdo,int count)285 static int dp_altmode_vdm(struct typec_altmode *alt,
286 const u32 hdr, const u32 *vdo, int count)
287 {
288 struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
289 int cmd_type = PD_VDO_CMDT(hdr);
290 int cmd = PD_VDO_CMD(hdr);
291 int ret = 0;
292
293 mutex_lock(&dp->lock);
294
295 if (dp->state != DP_STATE_IDLE) {
296 ret = -EBUSY;
297 goto err_unlock;
298 }
299
300 switch (cmd_type) {
301 case CMDT_RSP_ACK:
302 switch (cmd) {
303 case CMD_ENTER_MODE:
304 typec_altmode_update_active(alt, true);
305 dp->state = DP_STATE_UPDATE;
306 break;
307 case CMD_EXIT_MODE:
308 typec_altmode_update_active(alt, false);
309 dp->data.status = 0;
310 dp->data.conf = 0;
311 if (dp->hpd) {
312 drm_connector_oob_hotplug_event(dp->connector_fwnode,
313 connector_status_disconnected);
314 dp->hpd = false;
315 sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
316 }
317 break;
318 case DP_CMD_STATUS_UPDATE:
319 dp->data.status = *vdo;
320 ret = dp_altmode_status_update(dp);
321 break;
322 case DP_CMD_CONFIGURE:
323 ret = dp_altmode_configured(dp);
324 break;
325 default:
326 break;
327 }
328 break;
329 case CMDT_RSP_NAK:
330 switch (cmd) {
331 case DP_CMD_CONFIGURE:
332 dp->data.conf = 0;
333 ret = dp_altmode_configured(dp);
334 break;
335 default:
336 break;
337 }
338 break;
339 default:
340 break;
341 }
342
343 if (dp->state != DP_STATE_IDLE)
344 schedule_work(&dp->work);
345
346 err_unlock:
347 mutex_unlock(&dp->lock);
348 return ret;
349 }
350
dp_altmode_activate(struct typec_altmode * alt,int activate)351 static int dp_altmode_activate(struct typec_altmode *alt, int activate)
352 {
353 return activate ? typec_altmode_enter(alt, NULL) :
354 typec_altmode_exit(alt);
355 }
356
357 static const struct typec_altmode_ops dp_altmode_ops = {
358 .attention = dp_altmode_attention,
359 .vdm = dp_altmode_vdm,
360 .activate = dp_altmode_activate,
361 };
362
363 static const char * const configurations[] = {
364 [DP_CONF_USB] = "USB",
365 [DP_CONF_DFP_D] = "source",
366 [DP_CONF_UFP_D] = "sink",
367 };
368
369 static ssize_t
configuration_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)370 configuration_store(struct device *dev, struct device_attribute *attr,
371 const char *buf, size_t size)
372 {
373 struct dp_altmode *dp = dev_get_drvdata(dev);
374 u32 conf;
375 u32 cap;
376 int con;
377 int ret = 0;
378
379 con = sysfs_match_string(configurations, buf);
380 if (con < 0)
381 return con;
382
383 mutex_lock(&dp->lock);
384
385 if (dp->state != DP_STATE_IDLE) {
386 ret = -EBUSY;
387 goto err_unlock;
388 }
389
390 cap = DP_CAP_CAPABILITY(dp->alt->vdo);
391
392 if ((con == DP_CONF_DFP_D && !(cap & DP_CAP_DFP_D)) ||
393 (con == DP_CONF_UFP_D && !(cap & DP_CAP_UFP_D))) {
394 ret = -EINVAL;
395 goto err_unlock;
396 }
397
398 conf = dp->data.conf & ~DP_CONF_DUAL_D;
399 conf |= con;
400
401 if (dp->alt->active) {
402 ret = dp_altmode_configure_vdm(dp, conf);
403 if (ret)
404 goto err_unlock;
405 }
406
407 dp->data.conf = conf;
408
409 err_unlock:
410 mutex_unlock(&dp->lock);
411
412 return ret ? ret : size;
413 }
414
configuration_show(struct device * dev,struct device_attribute * attr,char * buf)415 static ssize_t configuration_show(struct device *dev,
416 struct device_attribute *attr, char *buf)
417 {
418 struct dp_altmode *dp = dev_get_drvdata(dev);
419 int len;
420 u8 cap;
421 u8 cur;
422 int i;
423
424 mutex_lock(&dp->lock);
425
426 cap = DP_CAP_CAPABILITY(dp->alt->vdo);
427 cur = DP_CONF_CURRENTLY(dp->data.conf);
428
429 len = sprintf(buf, "%s ", cur ? "USB" : "[USB]");
430
431 for (i = 1; i < ARRAY_SIZE(configurations); i++) {
432 if (i == cur)
433 len += sprintf(buf + len, "[%s] ", configurations[i]);
434 else if ((i == DP_CONF_DFP_D && cap & DP_CAP_DFP_D) ||
435 (i == DP_CONF_UFP_D && cap & DP_CAP_UFP_D))
436 len += sprintf(buf + len, "%s ", configurations[i]);
437 }
438
439 mutex_unlock(&dp->lock);
440
441 buf[len - 1] = '\n';
442 return len;
443 }
444 static DEVICE_ATTR_RW(configuration);
445
446 static const char * const pin_assignments[] = {
447 [DP_PIN_ASSIGN_A] = "A",
448 [DP_PIN_ASSIGN_B] = "B",
449 [DP_PIN_ASSIGN_C] = "C",
450 [DP_PIN_ASSIGN_D] = "D",
451 [DP_PIN_ASSIGN_E] = "E",
452 [DP_PIN_ASSIGN_F] = "F",
453 };
454
455 /*
456 * Helper function to extract a peripheral's currently supported
457 * Pin Assignments from its DisplayPort alternate mode state.
458 */
get_current_pin_assignments(struct dp_altmode * dp)459 static u8 get_current_pin_assignments(struct dp_altmode *dp)
460 {
461 if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_UFP_U_AS_DFP_D)
462 return DP_CAP_PIN_ASSIGN_DFP_D(dp->alt->vdo);
463 else
464 return DP_CAP_PIN_ASSIGN_UFP_D(dp->alt->vdo);
465 }
466
467 static ssize_t
pin_assignment_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)468 pin_assignment_store(struct device *dev, struct device_attribute *attr,
469 const char *buf, size_t size)
470 {
471 struct dp_altmode *dp = dev_get_drvdata(dev);
472 u8 assignments;
473 u32 conf;
474 int ret;
475
476 ret = sysfs_match_string(pin_assignments, buf);
477 if (ret < 0)
478 return ret;
479
480 conf = DP_CONF_SET_PIN_ASSIGN(BIT(ret));
481 ret = 0;
482
483 mutex_lock(&dp->lock);
484
485 if (conf & dp->data.conf)
486 goto out_unlock;
487
488 if (dp->state != DP_STATE_IDLE) {
489 ret = -EBUSY;
490 goto out_unlock;
491 }
492
493 assignments = get_current_pin_assignments(dp);
494
495 if (!(DP_CONF_GET_PIN_ASSIGN(conf) & assignments)) {
496 ret = -EINVAL;
497 goto out_unlock;
498 }
499
500 conf |= dp->data.conf & ~DP_CONF_PIN_ASSIGNEMENT_MASK;
501
502 /* Only send Configure command if a configuration has been set */
503 if (dp->alt->active && DP_CONF_CURRENTLY(dp->data.conf)) {
504 ret = dp_altmode_configure_vdm(dp, conf);
505 if (ret)
506 goto out_unlock;
507 }
508
509 dp->data.conf = conf;
510
511 out_unlock:
512 mutex_unlock(&dp->lock);
513
514 return ret ? ret : size;
515 }
516
pin_assignment_show(struct device * dev,struct device_attribute * attr,char * buf)517 static ssize_t pin_assignment_show(struct device *dev,
518 struct device_attribute *attr, char *buf)
519 {
520 struct dp_altmode *dp = dev_get_drvdata(dev);
521 u8 assignments;
522 int len = 0;
523 u8 cur;
524 int i;
525
526 mutex_lock(&dp->lock);
527
528 cur = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf));
529
530 assignments = get_current_pin_assignments(dp);
531
532 for (i = 0; assignments; assignments >>= 1, i++) {
533 if (assignments & 1) {
534 if (i == cur)
535 len += sprintf(buf + len, "[%s] ",
536 pin_assignments[i]);
537 else
538 len += sprintf(buf + len, "%s ",
539 pin_assignments[i]);
540 }
541 }
542
543 mutex_unlock(&dp->lock);
544
545 /* get_current_pin_assignments can return 0 when no matching pin assignments are found */
546 if (len == 0)
547 len++;
548
549 buf[len - 1] = '\n';
550 return len;
551 }
552 static DEVICE_ATTR_RW(pin_assignment);
553
hpd_show(struct device * dev,struct device_attribute * attr,char * buf)554 static ssize_t hpd_show(struct device *dev, struct device_attribute *attr, char *buf)
555 {
556 struct dp_altmode *dp = dev_get_drvdata(dev);
557
558 return sysfs_emit(buf, "%d\n", dp->hpd);
559 }
560 static DEVICE_ATTR_RO(hpd);
561
562 static struct attribute *displayport_attrs[] = {
563 &dev_attr_configuration.attr,
564 &dev_attr_pin_assignment.attr,
565 &dev_attr_hpd.attr,
566 NULL
567 };
568
569 static const struct attribute_group displayport_group = {
570 .name = "displayport",
571 .attrs = displayport_attrs,
572 };
573
574 static const struct attribute_group *displayport_groups[] = {
575 &displayport_group,
576 NULL,
577 };
578
dp_altmode_probe(struct typec_altmode * alt)579 int dp_altmode_probe(struct typec_altmode *alt)
580 {
581 const struct typec_altmode *port = typec_altmode_get_partner(alt);
582 struct fwnode_handle *fwnode;
583 struct dp_altmode *dp;
584
585 /* FIXME: Port can only be DFP_U. */
586
587 /* Make sure we have compatiple pin configurations */
588 if (!(DP_CAP_PIN_ASSIGN_DFP_D(port->vdo) &
589 DP_CAP_PIN_ASSIGN_UFP_D(alt->vdo)) &&
590 !(DP_CAP_PIN_ASSIGN_UFP_D(port->vdo) &
591 DP_CAP_PIN_ASSIGN_DFP_D(alt->vdo)))
592 return -ENODEV;
593
594 dp = devm_kzalloc(&alt->dev, sizeof(*dp), GFP_KERNEL);
595 if (!dp)
596 return -ENOMEM;
597
598 INIT_WORK(&dp->work, dp_altmode_work);
599 mutex_init(&dp->lock);
600 dp->port = port;
601 dp->alt = alt;
602
603 alt->desc = "DisplayPort";
604 alt->ops = &dp_altmode_ops;
605
606 fwnode = dev_fwnode(alt->dev.parent->parent); /* typec_port fwnode */
607 if (fwnode_property_present(fwnode, "displayport"))
608 dp->connector_fwnode = fwnode_find_reference(fwnode, "displayport", 0);
609 else
610 dp->connector_fwnode = fwnode_handle_get(fwnode); /* embedded DP */
611 if (IS_ERR(dp->connector_fwnode))
612 dp->connector_fwnode = NULL;
613
614 typec_altmode_set_drvdata(alt, dp);
615
616 dp->state = DP_STATE_ENTER;
617 schedule_work(&dp->work);
618
619 return 0;
620 }
621 EXPORT_SYMBOL_GPL(dp_altmode_probe);
622
dp_altmode_remove(struct typec_altmode * alt)623 void dp_altmode_remove(struct typec_altmode *alt)
624 {
625 struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
626
627 cancel_work_sync(&dp->work);
628
629 if (dp->connector_fwnode) {
630 drm_connector_oob_hotplug_event(dp->connector_fwnode,
631 connector_status_disconnected);
632
633 fwnode_handle_put(dp->connector_fwnode);
634 }
635 }
636 EXPORT_SYMBOL_GPL(dp_altmode_remove);
637
638 static const struct typec_device_id dp_typec_id[] = {
639 { USB_TYPEC_DP_SID, USB_TYPEC_DP_MODE },
640 { },
641 };
642 MODULE_DEVICE_TABLE(typec, dp_typec_id);
643
644 static struct typec_altmode_driver dp_altmode_driver = {
645 .id_table = dp_typec_id,
646 .probe = dp_altmode_probe,
647 .remove = dp_altmode_remove,
648 .driver = {
649 .name = "typec_displayport",
650 .owner = THIS_MODULE,
651 .dev_groups = displayport_groups,
652 },
653 };
654 module_typec_altmode_driver(dp_altmode_driver);
655
656 MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
657 MODULE_LICENSE("GPL v2");
658 MODULE_DESCRIPTION("DisplayPort Alternate Mode");
659