xref: /openbmc/linux/drivers/usb/core/port.c (revision f3539c12)
1 /*
2  * usb port device code
3  *
4  * Copyright (C) 2012 Intel Corp
5  *
6  * Author: Lan Tianyu <tianyu.lan@intel.com>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  *
12  * This program is distributed in the hope that it will be useful, but
13  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15  * for more details.
16  *
17  */
18 
19 #include <linux/slab.h>
20 #include <linux/pm_qos.h>
21 
22 #include "hub.h"
23 
24 static int usb_port_block_power_off;
25 
26 static const struct attribute_group *port_dev_group[];
27 
28 static ssize_t connect_type_show(struct device *dev,
29 				 struct device_attribute *attr, char *buf)
30 {
31 	struct usb_port *port_dev = to_usb_port(dev);
32 	char *result;
33 
34 	switch (port_dev->connect_type) {
35 	case USB_PORT_CONNECT_TYPE_HOT_PLUG:
36 		result = "hotplug";
37 		break;
38 	case USB_PORT_CONNECT_TYPE_HARD_WIRED:
39 		result = "hardwired";
40 		break;
41 	case USB_PORT_NOT_USED:
42 		result = "not used";
43 		break;
44 	default:
45 		result = "unknown";
46 		break;
47 	}
48 
49 	return sprintf(buf, "%s\n", result);
50 }
51 static DEVICE_ATTR_RO(connect_type);
52 
53 static ssize_t usb3_lpm_permit_show(struct device *dev,
54 			      struct device_attribute *attr, char *buf)
55 {
56 	struct usb_port *port_dev = to_usb_port(dev);
57 	const char *p;
58 
59 	if (port_dev->usb3_lpm_u1_permit) {
60 		if (port_dev->usb3_lpm_u2_permit)
61 			p = "u1_u2";
62 		else
63 			p = "u1";
64 	} else {
65 		if (port_dev->usb3_lpm_u2_permit)
66 			p = "u2";
67 		else
68 			p = "0";
69 	}
70 
71 	return sprintf(buf, "%s\n", p);
72 }
73 
74 static ssize_t usb3_lpm_permit_store(struct device *dev,
75 			       struct device_attribute *attr,
76 			       const char *buf, size_t count)
77 {
78 	struct usb_port *port_dev = to_usb_port(dev);
79 	struct usb_device *udev = port_dev->child;
80 	struct usb_hcd *hcd;
81 
82 	if (!strncmp(buf, "u1_u2", 5)) {
83 		port_dev->usb3_lpm_u1_permit = 1;
84 		port_dev->usb3_lpm_u2_permit = 1;
85 
86 	} else if (!strncmp(buf, "u1", 2)) {
87 		port_dev->usb3_lpm_u1_permit = 1;
88 		port_dev->usb3_lpm_u2_permit = 0;
89 
90 	} else if (!strncmp(buf, "u2", 2)) {
91 		port_dev->usb3_lpm_u1_permit = 0;
92 		port_dev->usb3_lpm_u2_permit = 1;
93 
94 	} else if (!strncmp(buf, "0", 1)) {
95 		port_dev->usb3_lpm_u1_permit = 0;
96 		port_dev->usb3_lpm_u2_permit = 0;
97 	} else
98 		return -EINVAL;
99 
100 	/* If device is connected to the port, disable or enable lpm
101 	 * to make new u1 u2 setting take effect immediately.
102 	 */
103 	if (udev) {
104 		hcd = bus_to_hcd(udev->bus);
105 		if (!hcd)
106 			return -EINVAL;
107 		usb_lock_device(udev);
108 		mutex_lock(hcd->bandwidth_mutex);
109 		if (!usb_disable_lpm(udev))
110 			usb_enable_lpm(udev);
111 		mutex_unlock(hcd->bandwidth_mutex);
112 		usb_unlock_device(udev);
113 	}
114 
115 	return count;
116 }
117 static DEVICE_ATTR_RW(usb3_lpm_permit);
118 
119 static struct attribute *port_dev_attrs[] = {
120 	&dev_attr_connect_type.attr,
121 	NULL,
122 };
123 
124 static struct attribute_group port_dev_attr_grp = {
125 	.attrs = port_dev_attrs,
126 };
127 
128 static const struct attribute_group *port_dev_group[] = {
129 	&port_dev_attr_grp,
130 	NULL,
131 };
132 
133 static struct attribute *port_dev_usb3_attrs[] = {
134 	&dev_attr_usb3_lpm_permit.attr,
135 	NULL,
136 };
137 
138 static struct attribute_group port_dev_usb3_attr_grp = {
139 	.attrs = port_dev_usb3_attrs,
140 };
141 
142 static const struct attribute_group *port_dev_usb3_group[] = {
143 	&port_dev_attr_grp,
144 	&port_dev_usb3_attr_grp,
145 	NULL,
146 };
147 
148 static void usb_port_device_release(struct device *dev)
149 {
150 	struct usb_port *port_dev = to_usb_port(dev);
151 
152 	kfree(port_dev->req);
153 	kfree(port_dev);
154 }
155 
156 #ifdef CONFIG_PM
157 static int usb_port_runtime_resume(struct device *dev)
158 {
159 	struct usb_port *port_dev = to_usb_port(dev);
160 	struct usb_device *hdev = to_usb_device(dev->parent->parent);
161 	struct usb_interface *intf = to_usb_interface(dev->parent);
162 	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
163 	struct usb_device *udev = port_dev->child;
164 	struct usb_port *peer = port_dev->peer;
165 	int port1 = port_dev->portnum;
166 	int retval;
167 
168 	if (!hub)
169 		return -EINVAL;
170 	if (hub->in_reset) {
171 		set_bit(port1, hub->power_bits);
172 		return 0;
173 	}
174 
175 	/*
176 	 * Power on our usb3 peer before this usb2 port to prevent a usb3
177 	 * device from degrading to its usb2 connection
178 	 */
179 	if (!port_dev->is_superspeed && peer)
180 		pm_runtime_get_sync(&peer->dev);
181 
182 	usb_autopm_get_interface(intf);
183 	retval = usb_hub_set_port_power(hdev, hub, port1, true);
184 	msleep(hub_power_on_good_delay(hub));
185 	if (udev && !retval) {
186 		/*
187 		 * Our preference is to simply wait for the port to reconnect,
188 		 * as that is the lowest latency method to restart the port.
189 		 * However, there are cases where toggling port power results in
190 		 * the host port and the device port getting out of sync causing
191 		 * a link training live lock.  Upon timeout, flag the port as
192 		 * needing warm reset recovery (to be performed later by
193 		 * usb_port_resume() as requested via usb_wakeup_notification())
194 		 */
195 		if (hub_port_debounce_be_connected(hub, port1) < 0) {
196 			dev_dbg(&port_dev->dev, "reconnect timeout\n");
197 			if (hub_is_superspeed(hdev))
198 				set_bit(port1, hub->warm_reset_bits);
199 		}
200 
201 		/* Force the child awake to revalidate after the power loss. */
202 		if (!test_and_set_bit(port1, hub->child_usage_bits)) {
203 			pm_runtime_get_noresume(&port_dev->dev);
204 			pm_request_resume(&udev->dev);
205 		}
206 	}
207 
208 	usb_autopm_put_interface(intf);
209 
210 	return retval;
211 }
212 
213 static int usb_port_runtime_suspend(struct device *dev)
214 {
215 	struct usb_port *port_dev = to_usb_port(dev);
216 	struct usb_device *hdev = to_usb_device(dev->parent->parent);
217 	struct usb_interface *intf = to_usb_interface(dev->parent);
218 	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
219 	struct usb_port *peer = port_dev->peer;
220 	int port1 = port_dev->portnum;
221 	int retval;
222 
223 	if (!hub)
224 		return -EINVAL;
225 	if (hub->in_reset)
226 		return -EBUSY;
227 
228 	if (dev_pm_qos_flags(&port_dev->dev, PM_QOS_FLAG_NO_POWER_OFF)
229 			== PM_QOS_FLAGS_ALL)
230 		return -EAGAIN;
231 
232 	if (usb_port_block_power_off)
233 		return -EBUSY;
234 
235 	usb_autopm_get_interface(intf);
236 	retval = usb_hub_set_port_power(hdev, hub, port1, false);
237 	usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION);
238 	if (!port_dev->is_superspeed)
239 		usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
240 	usb_autopm_put_interface(intf);
241 
242 	/*
243 	 * Our peer usb3 port may now be able to suspend, so
244 	 * asynchronously queue a suspend request to observe that this
245 	 * usb2 port is now off.
246 	 */
247 	if (!port_dev->is_superspeed && peer)
248 		pm_runtime_put(&peer->dev);
249 
250 	return retval;
251 }
252 #endif
253 
254 static const struct dev_pm_ops usb_port_pm_ops = {
255 #ifdef CONFIG_PM
256 	.runtime_suspend =	usb_port_runtime_suspend,
257 	.runtime_resume =	usb_port_runtime_resume,
258 #endif
259 };
260 
261 struct device_type usb_port_device_type = {
262 	.name =		"usb_port",
263 	.release =	usb_port_device_release,
264 	.pm =		&usb_port_pm_ops,
265 };
266 
267 static struct device_driver usb_port_driver = {
268 	.name = "usb",
269 	.owner = THIS_MODULE,
270 };
271 
272 static int link_peers(struct usb_port *left, struct usb_port *right)
273 {
274 	struct usb_port *ss_port, *hs_port;
275 	int rc;
276 
277 	if (left->peer == right && right->peer == left)
278 		return 0;
279 
280 	if (left->peer || right->peer) {
281 		struct usb_port *lpeer = left->peer;
282 		struct usb_port *rpeer = right->peer;
283 		char *method;
284 
285 		if (left->location && left->location == right->location)
286 			method = "location";
287 		else
288 			method = "default";
289 
290 		pr_debug("usb: failed to peer %s and %s by %s (%s:%s) (%s:%s)\n",
291 			dev_name(&left->dev), dev_name(&right->dev), method,
292 			dev_name(&left->dev),
293 			lpeer ? dev_name(&lpeer->dev) : "none",
294 			dev_name(&right->dev),
295 			rpeer ? dev_name(&rpeer->dev) : "none");
296 		return -EBUSY;
297 	}
298 
299 	rc = sysfs_create_link(&left->dev.kobj, &right->dev.kobj, "peer");
300 	if (rc)
301 		return rc;
302 	rc = sysfs_create_link(&right->dev.kobj, &left->dev.kobj, "peer");
303 	if (rc) {
304 		sysfs_remove_link(&left->dev.kobj, "peer");
305 		return rc;
306 	}
307 
308 	/*
309 	 * We need to wake the HiSpeed port to make sure we don't race
310 	 * setting ->peer with usb_port_runtime_suspend().  Otherwise we
311 	 * may miss a suspend event for the SuperSpeed port.
312 	 */
313 	if (left->is_superspeed) {
314 		ss_port = left;
315 		WARN_ON(right->is_superspeed);
316 		hs_port = right;
317 	} else {
318 		ss_port = right;
319 		WARN_ON(!right->is_superspeed);
320 		hs_port = left;
321 	}
322 	pm_runtime_get_sync(&hs_port->dev);
323 
324 	left->peer = right;
325 	right->peer = left;
326 
327 	/*
328 	 * The SuperSpeed reference is dropped when the HiSpeed port in
329 	 * this relationship suspends, i.e. when it is safe to allow a
330 	 * SuperSpeed connection to drop since there is no risk of a
331 	 * device degrading to its powered-off HiSpeed connection.
332 	 *
333 	 * Also, drop the HiSpeed ref taken above.
334 	 */
335 	pm_runtime_get_sync(&ss_port->dev);
336 	pm_runtime_put(&hs_port->dev);
337 
338 	return 0;
339 }
340 
341 static void link_peers_report(struct usb_port *left, struct usb_port *right)
342 {
343 	int rc;
344 
345 	rc = link_peers(left, right);
346 	if (rc == 0) {
347 		dev_dbg(&left->dev, "peered to %s\n", dev_name(&right->dev));
348 	} else {
349 		dev_dbg(&left->dev, "failed to peer to %s (%d)\n",
350 				dev_name(&right->dev), rc);
351 		pr_warn_once("usb: port power management may be unreliable\n");
352 		usb_port_block_power_off = 1;
353 	}
354 }
355 
356 static void unlink_peers(struct usb_port *left, struct usb_port *right)
357 {
358 	struct usb_port *ss_port, *hs_port;
359 
360 	WARN(right->peer != left || left->peer != right,
361 			"%s and %s are not peers?\n",
362 			dev_name(&left->dev), dev_name(&right->dev));
363 
364 	/*
365 	 * We wake the HiSpeed port to make sure we don't race its
366 	 * usb_port_runtime_resume() event which takes a SuperSpeed ref
367 	 * when ->peer is !NULL.
368 	 */
369 	if (left->is_superspeed) {
370 		ss_port = left;
371 		hs_port = right;
372 	} else {
373 		ss_port = right;
374 		hs_port = left;
375 	}
376 
377 	pm_runtime_get_sync(&hs_port->dev);
378 
379 	sysfs_remove_link(&left->dev.kobj, "peer");
380 	right->peer = NULL;
381 	sysfs_remove_link(&right->dev.kobj, "peer");
382 	left->peer = NULL;
383 
384 	/* Drop the SuperSpeed ref held on behalf of the active HiSpeed port */
385 	pm_runtime_put(&ss_port->dev);
386 
387 	/* Drop the ref taken above */
388 	pm_runtime_put(&hs_port->dev);
389 }
390 
391 /*
392  * For each usb hub device in the system check to see if it is in the
393  * peer domain of the given port_dev, and if it is check to see if it
394  * has a port that matches the given port by location
395  */
396 static int match_location(struct usb_device *peer_hdev, void *p)
397 {
398 	int port1;
399 	struct usb_hcd *hcd, *peer_hcd;
400 	struct usb_port *port_dev = p, *peer;
401 	struct usb_hub *peer_hub = usb_hub_to_struct_hub(peer_hdev);
402 	struct usb_device *hdev = to_usb_device(port_dev->dev.parent->parent);
403 
404 	if (!peer_hub)
405 		return 0;
406 
407 	hcd = bus_to_hcd(hdev->bus);
408 	peer_hcd = bus_to_hcd(peer_hdev->bus);
409 	/* peer_hcd is provisional until we verify it against the known peer */
410 	if (peer_hcd != hcd->shared_hcd)
411 		return 0;
412 
413 	for (port1 = 1; port1 <= peer_hdev->maxchild; port1++) {
414 		peer = peer_hub->ports[port1 - 1];
415 		if (peer && peer->location == port_dev->location) {
416 			link_peers_report(port_dev, peer);
417 			return 1; /* done */
418 		}
419 	}
420 
421 	return 0;
422 }
423 
424 /*
425  * Find the peer port either via explicit platform firmware "location"
426  * data, the peer hcd for root hubs, or the upstream peer relationship
427  * for all other hubs.
428  */
429 static void find_and_link_peer(struct usb_hub *hub, int port1)
430 {
431 	struct usb_port *port_dev = hub->ports[port1 - 1], *peer;
432 	struct usb_device *hdev = hub->hdev;
433 	struct usb_device *peer_hdev;
434 	struct usb_hub *peer_hub;
435 
436 	/*
437 	 * If location data is available then we can only peer this port
438 	 * by a location match, not the default peer (lest we create a
439 	 * situation where we need to go back and undo a default peering
440 	 * when the port is later peered by location data)
441 	 */
442 	if (port_dev->location) {
443 		/* we link the peer in match_location() if found */
444 		usb_for_each_dev(port_dev, match_location);
445 		return;
446 	} else if (!hdev->parent) {
447 		struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
448 		struct usb_hcd *peer_hcd = hcd->shared_hcd;
449 
450 		if (!peer_hcd)
451 			return;
452 
453 		peer_hdev = peer_hcd->self.root_hub;
454 	} else {
455 		struct usb_port *upstream;
456 		struct usb_device *parent = hdev->parent;
457 		struct usb_hub *parent_hub = usb_hub_to_struct_hub(parent);
458 
459 		if (!parent_hub)
460 			return;
461 
462 		upstream = parent_hub->ports[hdev->portnum - 1];
463 		if (!upstream || !upstream->peer)
464 			return;
465 
466 		peer_hdev = upstream->peer->child;
467 	}
468 
469 	peer_hub = usb_hub_to_struct_hub(peer_hdev);
470 	if (!peer_hub || port1 > peer_hdev->maxchild)
471 		return;
472 
473 	/*
474 	 * we found a valid default peer, last check is to make sure it
475 	 * does not have location data
476 	 */
477 	peer = peer_hub->ports[port1 - 1];
478 	if (peer && peer->location == 0)
479 		link_peers_report(port_dev, peer);
480 }
481 
482 int usb_hub_create_port_device(struct usb_hub *hub, int port1)
483 {
484 	struct usb_port *port_dev;
485 	struct usb_device *hdev = hub->hdev;
486 	int retval;
487 
488 	port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
489 	if (!port_dev)
490 		return -ENOMEM;
491 
492 	port_dev->req = kzalloc(sizeof(*(port_dev->req)), GFP_KERNEL);
493 	if (!port_dev->req) {
494 		kfree(port_dev);
495 		return -ENOMEM;
496 	}
497 
498 	hub->ports[port1 - 1] = port_dev;
499 	port_dev->portnum = port1;
500 	set_bit(port1, hub->power_bits);
501 	port_dev->dev.parent = hub->intfdev;
502 	if (hub_is_superspeed(hdev)) {
503 		port_dev->usb3_lpm_u1_permit = 1;
504 		port_dev->usb3_lpm_u2_permit = 1;
505 		port_dev->dev.groups = port_dev_usb3_group;
506 	} else
507 		port_dev->dev.groups = port_dev_group;
508 	port_dev->dev.type = &usb_port_device_type;
509 	port_dev->dev.driver = &usb_port_driver;
510 	if (hub_is_superspeed(hub->hdev))
511 		port_dev->is_superspeed = 1;
512 	dev_set_name(&port_dev->dev, "%s-port%d", dev_name(&hub->hdev->dev),
513 			port1);
514 	mutex_init(&port_dev->status_lock);
515 	retval = device_register(&port_dev->dev);
516 	if (retval) {
517 		put_device(&port_dev->dev);
518 		return retval;
519 	}
520 
521 	/* Set default policy of port-poweroff disabled. */
522 	retval = dev_pm_qos_add_request(&port_dev->dev, port_dev->req,
523 			DEV_PM_QOS_FLAGS, PM_QOS_FLAG_NO_POWER_OFF);
524 	if (retval < 0) {
525 		device_unregister(&port_dev->dev);
526 		return retval;
527 	}
528 
529 	find_and_link_peer(hub, port1);
530 
531 	/*
532 	 * Enable runtime pm and hold a refernce that hub_configure()
533 	 * will drop once the PM_QOS_NO_POWER_OFF flag state has been set
534 	 * and the hub has been fully registered (hdev->maxchild set).
535 	 */
536 	pm_runtime_set_active(&port_dev->dev);
537 	pm_runtime_get_noresume(&port_dev->dev);
538 	pm_runtime_enable(&port_dev->dev);
539 	device_enable_async_suspend(&port_dev->dev);
540 
541 	/*
542 	 * Keep hidden the ability to enable port-poweroff if the hub
543 	 * does not support power switching.
544 	 */
545 	if (!hub_is_port_power_switchable(hub))
546 		return 0;
547 
548 	/* Attempt to let userspace take over the policy. */
549 	retval = dev_pm_qos_expose_flags(&port_dev->dev,
550 			PM_QOS_FLAG_NO_POWER_OFF);
551 	if (retval < 0) {
552 		dev_warn(&port_dev->dev, "failed to expose pm_qos_no_poweroff\n");
553 		return 0;
554 	}
555 
556 	/* Userspace owns the policy, drop the kernel 'no_poweroff' request. */
557 	retval = dev_pm_qos_remove_request(port_dev->req);
558 	if (retval >= 0) {
559 		kfree(port_dev->req);
560 		port_dev->req = NULL;
561 	}
562 	return 0;
563 }
564 
565 void usb_hub_remove_port_device(struct usb_hub *hub, int port1)
566 {
567 	struct usb_port *port_dev = hub->ports[port1 - 1];
568 	struct usb_port *peer;
569 
570 	peer = port_dev->peer;
571 	if (peer)
572 		unlink_peers(port_dev, peer);
573 	device_unregister(&port_dev->dev);
574 }
575