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