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
24static int usb_port_block_power_off;
25
26static const struct attribute_group *port_dev_group[];
27
28static 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}
51static DEVICE_ATTR_RO(connect_type);
52
53static struct attribute *port_dev_attrs[] = {
54	&dev_attr_connect_type.attr,
55	NULL,
56};
57
58static struct attribute_group port_dev_attr_grp = {
59	.attrs = port_dev_attrs,
60};
61
62static const struct attribute_group *port_dev_group[] = {
63	&port_dev_attr_grp,
64	NULL,
65};
66
67static void usb_port_device_release(struct device *dev)
68{
69	struct usb_port *port_dev = to_usb_port(dev);
70
71	kfree(port_dev->req);
72	kfree(port_dev);
73}
74
75#ifdef CONFIG_PM
76static int usb_port_runtime_resume(struct device *dev)
77{
78	struct usb_port *port_dev = to_usb_port(dev);
79	struct usb_device *hdev = to_usb_device(dev->parent->parent);
80	struct usb_interface *intf = to_usb_interface(dev->parent);
81	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
82	struct usb_device *udev = port_dev->child;
83	struct usb_port *peer = port_dev->peer;
84	int port1 = port_dev->portnum;
85	int retval;
86
87	if (!hub)
88		return -EINVAL;
89	if (hub->in_reset) {
90		set_bit(port1, hub->power_bits);
91		return 0;
92	}
93
94	/*
95	 * Power on our usb3 peer before this usb2 port to prevent a usb3
96	 * device from degrading to its usb2 connection
97	 */
98	if (!port_dev->is_superspeed && peer)
99		pm_runtime_get_sync(&peer->dev);
100
101	usb_autopm_get_interface(intf);
102	retval = usb_hub_set_port_power(hdev, hub, port1, true);
103	msleep(hub_power_on_good_delay(hub));
104	if (udev && !retval) {
105		/*
106		 * Our preference is to simply wait for the port to reconnect,
107		 * as that is the lowest latency method to restart the port.
108		 * However, there are cases where toggling port power results in
109		 * the host port and the device port getting out of sync causing
110		 * a link training live lock.  Upon timeout, flag the port as
111		 * needing warm reset recovery (to be performed later by
112		 * usb_port_resume() as requested via usb_wakeup_notification())
113		 */
114		if (hub_port_debounce_be_connected(hub, port1) < 0) {
115			dev_dbg(&port_dev->dev, "reconnect timeout\n");
116			if (hub_is_superspeed(hdev))
117				set_bit(port1, hub->warm_reset_bits);
118		}
119
120		/* Force the child awake to revalidate after the power loss. */
121		if (!test_and_set_bit(port1, hub->child_usage_bits)) {
122			pm_runtime_get_noresume(&port_dev->dev);
123			pm_request_resume(&udev->dev);
124		}
125	}
126
127	usb_autopm_put_interface(intf);
128
129	return retval;
130}
131
132static int usb_port_runtime_suspend(struct device *dev)
133{
134	struct usb_port *port_dev = to_usb_port(dev);
135	struct usb_device *hdev = to_usb_device(dev->parent->parent);
136	struct usb_interface *intf = to_usb_interface(dev->parent);
137	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
138	struct usb_port *peer = port_dev->peer;
139	int port1 = port_dev->portnum;
140	int retval;
141
142	if (!hub)
143		return -EINVAL;
144	if (hub->in_reset)
145		return -EBUSY;
146
147	if (dev_pm_qos_flags(&port_dev->dev, PM_QOS_FLAG_NO_POWER_OFF)
148			== PM_QOS_FLAGS_ALL)
149		return -EAGAIN;
150
151	if (usb_port_block_power_off)
152		return -EBUSY;
153
154	usb_autopm_get_interface(intf);
155	retval = usb_hub_set_port_power(hdev, hub, port1, false);
156	usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION);
157	if (!port_dev->is_superspeed)
158		usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
159	usb_autopm_put_interface(intf);
160
161	/*
162	 * Our peer usb3 port may now be able to suspend, so
163	 * asynchronously queue a suspend request to observe that this
164	 * usb2 port is now off.
165	 */
166	if (!port_dev->is_superspeed && peer)
167		pm_runtime_put(&peer->dev);
168
169	return retval;
170}
171#endif
172
173static const struct dev_pm_ops usb_port_pm_ops = {
174#ifdef CONFIG_PM
175	.runtime_suspend =	usb_port_runtime_suspend,
176	.runtime_resume =	usb_port_runtime_resume,
177#endif
178};
179
180struct device_type usb_port_device_type = {
181	.name =		"usb_port",
182	.release =	usb_port_device_release,
183	.pm =		&usb_port_pm_ops,
184};
185
186static struct device_driver usb_port_driver = {
187	.name = "usb",
188	.owner = THIS_MODULE,
189};
190
191static int link_peers(struct usb_port *left, struct usb_port *right)
192{
193	struct usb_port *ss_port, *hs_port;
194	int rc;
195
196	if (left->peer == right && right->peer == left)
197		return 0;
198
199	if (left->peer || right->peer) {
200		struct usb_port *lpeer = left->peer;
201		struct usb_port *rpeer = right->peer;
202		char *method;
203
204		if (left->location && left->location == right->location)
205			method = "location";
206		else
207			method = "default";
208
209		pr_warn("usb: failed to peer %s and %s by %s (%s:%s) (%s:%s)\n",
210			dev_name(&left->dev), dev_name(&right->dev), method,
211			dev_name(&left->dev),
212			lpeer ? dev_name(&lpeer->dev) : "none",
213			dev_name(&right->dev),
214			rpeer ? dev_name(&rpeer->dev) : "none");
215		return -EBUSY;
216	}
217
218	rc = sysfs_create_link(&left->dev.kobj, &right->dev.kobj, "peer");
219	if (rc)
220		return rc;
221	rc = sysfs_create_link(&right->dev.kobj, &left->dev.kobj, "peer");
222	if (rc) {
223		sysfs_remove_link(&left->dev.kobj, "peer");
224		return rc;
225	}
226
227	/*
228	 * We need to wake the HiSpeed port to make sure we don't race
229	 * setting ->peer with usb_port_runtime_suspend().  Otherwise we
230	 * may miss a suspend event for the SuperSpeed port.
231	 */
232	if (left->is_superspeed) {
233		ss_port = left;
234		WARN_ON(right->is_superspeed);
235		hs_port = right;
236	} else {
237		ss_port = right;
238		WARN_ON(!right->is_superspeed);
239		hs_port = left;
240	}
241	pm_runtime_get_sync(&hs_port->dev);
242
243	left->peer = right;
244	right->peer = left;
245
246	/*
247	 * The SuperSpeed reference is dropped when the HiSpeed port in
248	 * this relationship suspends, i.e. when it is safe to allow a
249	 * SuperSpeed connection to drop since there is no risk of a
250	 * device degrading to its powered-off HiSpeed connection.
251	 *
252	 * Also, drop the HiSpeed ref taken above.
253	 */
254	pm_runtime_get_sync(&ss_port->dev);
255	pm_runtime_put(&hs_port->dev);
256
257	return 0;
258}
259
260static void link_peers_report(struct usb_port *left, struct usb_port *right)
261{
262	int rc;
263
264	rc = link_peers(left, right);
265	if (rc == 0) {
266		dev_dbg(&left->dev, "peered to %s\n", dev_name(&right->dev));
267	} else {
268		dev_warn(&left->dev, "failed to peer to %s (%d)\n",
269				dev_name(&right->dev), rc);
270		pr_warn_once("usb: port power management may be unreliable\n");
271		usb_port_block_power_off = 1;
272	}
273}
274
275static void unlink_peers(struct usb_port *left, struct usb_port *right)
276{
277	struct usb_port *ss_port, *hs_port;
278
279	WARN(right->peer != left || left->peer != right,
280			"%s and %s are not peers?\n",
281			dev_name(&left->dev), dev_name(&right->dev));
282
283	/*
284	 * We wake the HiSpeed port to make sure we don't race its
285	 * usb_port_runtime_resume() event which takes a SuperSpeed ref
286	 * when ->peer is !NULL.
287	 */
288	if (left->is_superspeed) {
289		ss_port = left;
290		hs_port = right;
291	} else {
292		ss_port = right;
293		hs_port = left;
294	}
295
296	pm_runtime_get_sync(&hs_port->dev);
297
298	sysfs_remove_link(&left->dev.kobj, "peer");
299	right->peer = NULL;
300	sysfs_remove_link(&right->dev.kobj, "peer");
301	left->peer = NULL;
302
303	/* Drop the SuperSpeed ref held on behalf of the active HiSpeed port */
304	pm_runtime_put(&ss_port->dev);
305
306	/* Drop the ref taken above */
307	pm_runtime_put(&hs_port->dev);
308}
309
310/*
311 * For each usb hub device in the system check to see if it is in the
312 * peer domain of the given port_dev, and if it is check to see if it
313 * has a port that matches the given port by location
314 */
315static int match_location(struct usb_device *peer_hdev, void *p)
316{
317	int port1;
318	struct usb_hcd *hcd, *peer_hcd;
319	struct usb_port *port_dev = p, *peer;
320	struct usb_hub *peer_hub = usb_hub_to_struct_hub(peer_hdev);
321	struct usb_device *hdev = to_usb_device(port_dev->dev.parent->parent);
322
323	if (!peer_hub)
324		return 0;
325
326	hcd = bus_to_hcd(hdev->bus);
327	peer_hcd = bus_to_hcd(peer_hdev->bus);
328	/* peer_hcd is provisional until we verify it against the known peer */
329	if (peer_hcd != hcd->shared_hcd)
330		return 0;
331
332	for (port1 = 1; port1 <= peer_hdev->maxchild; port1++) {
333		peer = peer_hub->ports[port1 - 1];
334		if (peer && peer->location == port_dev->location) {
335			link_peers_report(port_dev, peer);
336			return 1; /* done */
337		}
338	}
339
340	return 0;
341}
342
343/*
344 * Find the peer port either via explicit platform firmware "location"
345 * data, the peer hcd for root hubs, or the upstream peer relationship
346 * for all other hubs.
347 */
348static void find_and_link_peer(struct usb_hub *hub, int port1)
349{
350	struct usb_port *port_dev = hub->ports[port1 - 1], *peer;
351	struct usb_device *hdev = hub->hdev;
352	struct usb_device *peer_hdev;
353	struct usb_hub *peer_hub;
354
355	/*
356	 * If location data is available then we can only peer this port
357	 * by a location match, not the default peer (lest we create a
358	 * situation where we need to go back and undo a default peering
359	 * when the port is later peered by location data)
360	 */
361	if (port_dev->location) {
362		/* we link the peer in match_location() if found */
363		usb_for_each_dev(port_dev, match_location);
364		return;
365	} else if (!hdev->parent) {
366		struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
367		struct usb_hcd *peer_hcd = hcd->shared_hcd;
368
369		if (!peer_hcd)
370			return;
371
372		peer_hdev = peer_hcd->self.root_hub;
373	} else {
374		struct usb_port *upstream;
375		struct usb_device *parent = hdev->parent;
376		struct usb_hub *parent_hub = usb_hub_to_struct_hub(parent);
377
378		if (!parent_hub)
379			return;
380
381		upstream = parent_hub->ports[hdev->portnum - 1];
382		if (!upstream || !upstream->peer)
383			return;
384
385		peer_hdev = upstream->peer->child;
386	}
387
388	peer_hub = usb_hub_to_struct_hub(peer_hdev);
389	if (!peer_hub || port1 > peer_hdev->maxchild)
390		return;
391
392	/*
393	 * we found a valid default peer, last check is to make sure it
394	 * does not have location data
395	 */
396	peer = peer_hub->ports[port1 - 1];
397	if (peer && peer->location == 0)
398		link_peers_report(port_dev, peer);
399}
400
401int usb_hub_create_port_device(struct usb_hub *hub, int port1)
402{
403	struct usb_port *port_dev;
404	int retval;
405
406	port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
407	if (!port_dev)
408		return -ENOMEM;
409
410	port_dev->req = kzalloc(sizeof(*(port_dev->req)), GFP_KERNEL);
411	if (!port_dev->req) {
412		kfree(port_dev);
413		return -ENOMEM;
414	}
415
416	hub->ports[port1 - 1] = port_dev;
417	port_dev->portnum = port1;
418	set_bit(port1, hub->power_bits);
419	port_dev->dev.parent = hub->intfdev;
420	port_dev->dev.groups = port_dev_group;
421	port_dev->dev.type = &usb_port_device_type;
422	port_dev->dev.driver = &usb_port_driver;
423	if (hub_is_superspeed(hub->hdev))
424		port_dev->is_superspeed = 1;
425	dev_set_name(&port_dev->dev, "%s-port%d", dev_name(&hub->hdev->dev),
426			port1);
427	mutex_init(&port_dev->status_lock);
428	retval = device_register(&port_dev->dev);
429	if (retval) {
430		put_device(&port_dev->dev);
431		return retval;
432	}
433
434	/* Set default policy of port-poweroff disabled. */
435	retval = dev_pm_qos_add_request(&port_dev->dev, port_dev->req,
436			DEV_PM_QOS_FLAGS, PM_QOS_FLAG_NO_POWER_OFF);
437	if (retval < 0) {
438		device_unregister(&port_dev->dev);
439		return retval;
440	}
441
442	find_and_link_peer(hub, port1);
443
444	/*
445	 * Enable runtime pm and hold a refernce that hub_configure()
446	 * will drop once the PM_QOS_NO_POWER_OFF flag state has been set
447	 * and the hub has been fully registered (hdev->maxchild set).
448	 */
449	pm_runtime_set_active(&port_dev->dev);
450	pm_runtime_get_noresume(&port_dev->dev);
451	pm_runtime_enable(&port_dev->dev);
452	device_enable_async_suspend(&port_dev->dev);
453
454	/*
455	 * Keep hidden the ability to enable port-poweroff if the hub
456	 * does not support power switching.
457	 */
458	if (!hub_is_port_power_switchable(hub))
459		return 0;
460
461	/* Attempt to let userspace take over the policy. */
462	retval = dev_pm_qos_expose_flags(&port_dev->dev,
463			PM_QOS_FLAG_NO_POWER_OFF);
464	if (retval < 0) {
465		dev_warn(&port_dev->dev, "failed to expose pm_qos_no_poweroff\n");
466		return 0;
467	}
468
469	/* Userspace owns the policy, drop the kernel 'no_poweroff' request. */
470	retval = dev_pm_qos_remove_request(port_dev->req);
471	if (retval >= 0) {
472		kfree(port_dev->req);
473		port_dev->req = NULL;
474	}
475	return 0;
476}
477
478void usb_hub_remove_port_device(struct usb_hub *hub, int port1)
479{
480	struct usb_port *port_dev = hub->ports[port1 - 1];
481	struct usb_port *peer;
482
483	peer = port_dev->peer;
484	if (peer)
485		unlink_peers(port_dev, peer);
486	device_unregister(&port_dev->dev);
487}
488