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 		}
150 	}
151 
152 	return ret;
153 }
154 
dp_altmode_configured(struct dp_altmode * dp)155 static int dp_altmode_configured(struct dp_altmode *dp)
156 {
157 	sysfs_notify(&dp->alt->dev.kobj, "displayport", "configuration");
158 	sysfs_notify(&dp->alt->dev.kobj, "displayport", "pin_assignment");
159 
160 	return dp_altmode_notify(dp);
161 }
162 
dp_altmode_configure_vdm(struct dp_altmode * dp,u32 conf)163 static int dp_altmode_configure_vdm(struct dp_altmode *dp, u32 conf)
164 {
165 	int svdm_version = typec_altmode_get_svdm_version(dp->alt);
166 	u32 header;
167 	int ret;
168 
169 	if (svdm_version < 0)
170 		return svdm_version;
171 
172 	header = DP_HEADER(dp, svdm_version, DP_CMD_CONFIGURE);
173 	ret = typec_altmode_notify(dp->alt, TYPEC_STATE_SAFE, &dp->data);
174 	if (ret) {
175 		dev_err(&dp->alt->dev,
176 			"unable to put to connector to safe mode\n");
177 		return ret;
178 	}
179 
180 	ret = typec_altmode_vdm(dp->alt, header, &conf, 2);
181 	if (ret)
182 		dp_altmode_notify(dp);
183 
184 	return ret;
185 }
186 
dp_altmode_work(struct work_struct * work)187 static void dp_altmode_work(struct work_struct *work)
188 {
189 	struct dp_altmode *dp = container_of(work, struct dp_altmode, work);
190 	int svdm_version;
191 	u32 header;
192 	u32 vdo;
193 	int ret;
194 
195 	mutex_lock(&dp->lock);
196 
197 	switch (dp->state) {
198 	case DP_STATE_ENTER:
199 		ret = typec_altmode_enter(dp->alt, NULL);
200 		if (ret && ret != -EBUSY)
201 			dev_err(&dp->alt->dev, "failed to enter mode\n");
202 		break;
203 	case DP_STATE_UPDATE:
204 		svdm_version = typec_altmode_get_svdm_version(dp->alt);
205 		if (svdm_version < 0)
206 			break;
207 		header = DP_HEADER(dp, svdm_version, DP_CMD_STATUS_UPDATE);
208 		vdo = 1;
209 		ret = typec_altmode_vdm(dp->alt, header, &vdo, 2);
210 		if (ret)
211 			dev_err(&dp->alt->dev,
212 				"unable to send Status Update command (%d)\n",
213 				ret);
214 		break;
215 	case DP_STATE_CONFIGURE:
216 		ret = dp_altmode_configure_vdm(dp, dp->data.conf);
217 		if (ret)
218 			dev_err(&dp->alt->dev,
219 				"unable to send Configure command (%d)\n", ret);
220 		break;
221 	case DP_STATE_EXIT:
222 		if (typec_altmode_exit(dp->alt))
223 			dev_err(&dp->alt->dev, "Exit Mode Failed!\n");
224 		break;
225 	default:
226 		break;
227 	}
228 
229 	dp->state = DP_STATE_IDLE;
230 
231 	mutex_unlock(&dp->lock);
232 }
233 
dp_altmode_attention(struct typec_altmode * alt,const u32 vdo)234 static void dp_altmode_attention(struct typec_altmode *alt, const u32 vdo)
235 {
236 	struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
237 	u8 old_state;
238 
239 	mutex_lock(&dp->lock);
240 
241 	old_state = dp->state;
242 	dp->data.status = vdo;
243 
244 	if (old_state != DP_STATE_IDLE)
245 		dev_warn(&alt->dev, "ATTENTION while processing state %d\n",
246 			 old_state);
247 
248 	if (dp_altmode_status_update(dp))
249 		dev_warn(&alt->dev, "%s: status update failed\n", __func__);
250 
251 	if (dp_altmode_notify(dp))
252 		dev_err(&alt->dev, "%s: notification failed\n", __func__);
253 
254 	if (old_state == DP_STATE_IDLE && dp->state != DP_STATE_IDLE)
255 		schedule_work(&dp->work);
256 
257 	mutex_unlock(&dp->lock);
258 }
259 
dp_altmode_vdm(struct typec_altmode * alt,const u32 hdr,const u32 * vdo,int count)260 static int dp_altmode_vdm(struct typec_altmode *alt,
261 			  const u32 hdr, const u32 *vdo, int count)
262 {
263 	struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
264 	int cmd_type = PD_VDO_CMDT(hdr);
265 	int cmd = PD_VDO_CMD(hdr);
266 	int ret = 0;
267 
268 	mutex_lock(&dp->lock);
269 
270 	if (dp->state != DP_STATE_IDLE) {
271 		ret = -EBUSY;
272 		goto err_unlock;
273 	}
274 
275 	switch (cmd_type) {
276 	case CMDT_RSP_ACK:
277 		switch (cmd) {
278 		case CMD_ENTER_MODE:
279 			dp->state = DP_STATE_UPDATE;
280 			break;
281 		case CMD_EXIT_MODE:
282 			dp->data.status = 0;
283 			dp->data.conf = 0;
284 			break;
285 		case DP_CMD_STATUS_UPDATE:
286 			dp->data.status = *vdo;
287 			ret = dp_altmode_status_update(dp);
288 			break;
289 		case DP_CMD_CONFIGURE:
290 			ret = dp_altmode_configured(dp);
291 			break;
292 		default:
293 			break;
294 		}
295 		break;
296 	case CMDT_RSP_NAK:
297 		switch (cmd) {
298 		case DP_CMD_CONFIGURE:
299 			dp->data.conf = 0;
300 			ret = dp_altmode_configured(dp);
301 			break;
302 		default:
303 			break;
304 		}
305 		break;
306 	default:
307 		break;
308 	}
309 
310 	if (dp->state != DP_STATE_IDLE)
311 		schedule_work(&dp->work);
312 
313 err_unlock:
314 	mutex_unlock(&dp->lock);
315 	return ret;
316 }
317 
dp_altmode_activate(struct typec_altmode * alt,int activate)318 static int dp_altmode_activate(struct typec_altmode *alt, int activate)
319 {
320 	return activate ? typec_altmode_enter(alt, NULL) :
321 			  typec_altmode_exit(alt);
322 }
323 
324 static const struct typec_altmode_ops dp_altmode_ops = {
325 	.attention = dp_altmode_attention,
326 	.vdm = dp_altmode_vdm,
327 	.activate = dp_altmode_activate,
328 };
329 
330 static const char * const configurations[] = {
331 	[DP_CONF_USB]	= "USB",
332 	[DP_CONF_DFP_D]	= "source",
333 	[DP_CONF_UFP_D]	= "sink",
334 };
335 
336 static ssize_t
configuration_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)337 configuration_store(struct device *dev, struct device_attribute *attr,
338 		    const char *buf, size_t size)
339 {
340 	struct dp_altmode *dp = dev_get_drvdata(dev);
341 	u32 conf;
342 	u32 cap;
343 	int con;
344 	int ret = 0;
345 
346 	con = sysfs_match_string(configurations, buf);
347 	if (con < 0)
348 		return con;
349 
350 	mutex_lock(&dp->lock);
351 
352 	if (dp->state != DP_STATE_IDLE) {
353 		ret = -EBUSY;
354 		goto err_unlock;
355 	}
356 
357 	cap = DP_CAP_CAPABILITY(dp->alt->vdo);
358 
359 	if ((con == DP_CONF_DFP_D && !(cap & DP_CAP_DFP_D)) ||
360 	    (con == DP_CONF_UFP_D && !(cap & DP_CAP_UFP_D))) {
361 		ret = -EINVAL;
362 		goto err_unlock;
363 	}
364 
365 	conf = dp->data.conf & ~DP_CONF_DUAL_D;
366 	conf |= con;
367 
368 	if (dp->alt->active) {
369 		ret = dp_altmode_configure_vdm(dp, conf);
370 		if (ret)
371 			goto err_unlock;
372 	}
373 
374 	dp->data.conf = conf;
375 
376 err_unlock:
377 	mutex_unlock(&dp->lock);
378 
379 	return ret ? ret : size;
380 }
381 
configuration_show(struct device * dev,struct device_attribute * attr,char * buf)382 static ssize_t configuration_show(struct device *dev,
383 				  struct device_attribute *attr, char *buf)
384 {
385 	struct dp_altmode *dp = dev_get_drvdata(dev);
386 	int len;
387 	u8 cap;
388 	u8 cur;
389 	int i;
390 
391 	mutex_lock(&dp->lock);
392 
393 	cap = DP_CAP_CAPABILITY(dp->alt->vdo);
394 	cur = DP_CONF_CURRENTLY(dp->data.conf);
395 
396 	len = sprintf(buf, "%s ", cur ? "USB" : "[USB]");
397 
398 	for (i = 1; i < ARRAY_SIZE(configurations); i++) {
399 		if (i == cur)
400 			len += sprintf(buf + len, "[%s] ", configurations[i]);
401 		else if ((i == DP_CONF_DFP_D && cap & DP_CAP_DFP_D) ||
402 			 (i == DP_CONF_UFP_D && cap & DP_CAP_UFP_D))
403 			len += sprintf(buf + len, "%s ", configurations[i]);
404 	}
405 
406 	mutex_unlock(&dp->lock);
407 
408 	buf[len - 1] = '\n';
409 	return len;
410 }
411 static DEVICE_ATTR_RW(configuration);
412 
413 static const char * const pin_assignments[] = {
414 	[DP_PIN_ASSIGN_A] = "A",
415 	[DP_PIN_ASSIGN_B] = "B",
416 	[DP_PIN_ASSIGN_C] = "C",
417 	[DP_PIN_ASSIGN_D] = "D",
418 	[DP_PIN_ASSIGN_E] = "E",
419 	[DP_PIN_ASSIGN_F] = "F",
420 };
421 
422 static ssize_t
pin_assignment_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)423 pin_assignment_store(struct device *dev, struct device_attribute *attr,
424 		     const char *buf, size_t size)
425 {
426 	struct dp_altmode *dp = dev_get_drvdata(dev);
427 	u8 assignments;
428 	u32 conf;
429 	int ret;
430 
431 	ret = sysfs_match_string(pin_assignments, buf);
432 	if (ret < 0)
433 		return ret;
434 
435 	conf = DP_CONF_SET_PIN_ASSIGN(BIT(ret));
436 	ret = 0;
437 
438 	mutex_lock(&dp->lock);
439 
440 	if (conf & dp->data.conf)
441 		goto out_unlock;
442 
443 	if (dp->state != DP_STATE_IDLE) {
444 		ret = -EBUSY;
445 		goto out_unlock;
446 	}
447 
448 	if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_DFP_D)
449 		assignments = DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo);
450 	else
451 		assignments = DP_CAP_DFP_D_PIN_ASSIGN(dp->alt->vdo);
452 
453 	if (!(DP_CONF_GET_PIN_ASSIGN(conf) & assignments)) {
454 		ret = -EINVAL;
455 		goto out_unlock;
456 	}
457 
458 	conf |= dp->data.conf & ~DP_CONF_PIN_ASSIGNEMENT_MASK;
459 
460 	/* Only send Configure command if a configuration has been set */
461 	if (dp->alt->active && DP_CONF_CURRENTLY(dp->data.conf)) {
462 		ret = dp_altmode_configure_vdm(dp, conf);
463 		if (ret)
464 			goto out_unlock;
465 	}
466 
467 	dp->data.conf = conf;
468 
469 out_unlock:
470 	mutex_unlock(&dp->lock);
471 
472 	return ret ? ret : size;
473 }
474 
pin_assignment_show(struct device * dev,struct device_attribute * attr,char * buf)475 static ssize_t pin_assignment_show(struct device *dev,
476 				   struct device_attribute *attr, char *buf)
477 {
478 	struct dp_altmode *dp = dev_get_drvdata(dev);
479 	u8 assignments;
480 	int len = 0;
481 	u8 cur;
482 	int i;
483 
484 	mutex_lock(&dp->lock);
485 
486 	cur = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf));
487 
488 	if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_DFP_D)
489 		assignments = DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo);
490 	else
491 		assignments = DP_CAP_DFP_D_PIN_ASSIGN(dp->alt->vdo);
492 
493 	for (i = 0; assignments; assignments >>= 1, i++) {
494 		if (assignments & 1) {
495 			if (i == cur)
496 				len += sprintf(buf + len, "[%s] ",
497 					       pin_assignments[i]);
498 			else
499 				len += sprintf(buf + len, "%s ",
500 					       pin_assignments[i]);
501 		}
502 	}
503 
504 	mutex_unlock(&dp->lock);
505 
506 	buf[len - 1] = '\n';
507 	return len;
508 }
509 static DEVICE_ATTR_RW(pin_assignment);
510 
511 static struct attribute *dp_altmode_attrs[] = {
512 	&dev_attr_configuration.attr,
513 	&dev_attr_pin_assignment.attr,
514 	NULL
515 };
516 
517 static const struct attribute_group dp_altmode_group = {
518 	.name = "displayport",
519 	.attrs = dp_altmode_attrs,
520 };
521 
dp_altmode_probe(struct typec_altmode * alt)522 int dp_altmode_probe(struct typec_altmode *alt)
523 {
524 	const struct typec_altmode *port = typec_altmode_get_partner(alt);
525 	struct fwnode_handle *fwnode;
526 	struct dp_altmode *dp;
527 	int ret;
528 
529 	/* FIXME: Port can only be DFP_U. */
530 
531 	/* Make sure we have compatiple pin configurations */
532 	if (!(DP_CAP_DFP_D_PIN_ASSIGN(port->vdo) &
533 	      DP_CAP_UFP_D_PIN_ASSIGN(alt->vdo)) &&
534 	    !(DP_CAP_UFP_D_PIN_ASSIGN(port->vdo) &
535 	      DP_CAP_DFP_D_PIN_ASSIGN(alt->vdo)))
536 		return -ENODEV;
537 
538 	ret = sysfs_create_group(&alt->dev.kobj, &dp_altmode_group);
539 	if (ret)
540 		return ret;
541 
542 	dp = devm_kzalloc(&alt->dev, sizeof(*dp), GFP_KERNEL);
543 	if (!dp)
544 		return -ENOMEM;
545 
546 	INIT_WORK(&dp->work, dp_altmode_work);
547 	mutex_init(&dp->lock);
548 	dp->port = port;
549 	dp->alt = alt;
550 
551 	alt->desc = "DisplayPort";
552 	alt->ops = &dp_altmode_ops;
553 
554 	fwnode = dev_fwnode(alt->dev.parent->parent); /* typec_port fwnode */
555 	dp->connector_fwnode = fwnode_find_reference(fwnode, "displayport", 0);
556 	if (IS_ERR(dp->connector_fwnode))
557 		dp->connector_fwnode = NULL;
558 
559 	typec_altmode_set_drvdata(alt, dp);
560 
561 	dp->state = DP_STATE_ENTER;
562 	schedule_work(&dp->work);
563 
564 	return 0;
565 }
566 EXPORT_SYMBOL_GPL(dp_altmode_probe);
567 
dp_altmode_remove(struct typec_altmode * alt)568 void dp_altmode_remove(struct typec_altmode *alt)
569 {
570 	struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
571 
572 	sysfs_remove_group(&alt->dev.kobj, &dp_altmode_group);
573 	cancel_work_sync(&dp->work);
574 
575 	if (dp->connector_fwnode) {
576 		if (dp->hpd)
577 			drm_connector_oob_hotplug_event(dp->connector_fwnode);
578 
579 		fwnode_handle_put(dp->connector_fwnode);
580 	}
581 }
582 EXPORT_SYMBOL_GPL(dp_altmode_remove);
583 
584 static const struct typec_device_id dp_typec_id[] = {
585 	{ USB_TYPEC_DP_SID, USB_TYPEC_DP_MODE },
586 	{ },
587 };
588 MODULE_DEVICE_TABLE(typec, dp_typec_id);
589 
590 static struct typec_altmode_driver dp_altmode_driver = {
591 	.id_table = dp_typec_id,
592 	.probe = dp_altmode_probe,
593 	.remove = dp_altmode_remove,
594 	.driver = {
595 		.name = "typec_displayport",
596 		.owner = THIS_MODULE,
597 	},
598 };
599 module_typec_altmode_driver(dp_altmode_driver);
600 
601 MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
602 MODULE_LICENSE("GPL v2");
603 MODULE_DESCRIPTION("DisplayPort Alternate Mode");
604