[linux-2.6-block.git] / drivers / usb / core / port.c

/*
 * usb port device code
 *
 * Copyright (C) 2012 Intel Corp
 *
 * Author: Lan Tianyu <tianyu.lan@intel.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 */

#include <linux/slab.h>
#include <linux/pm_qos.h>

#include "hub.h"

static int usb_port_block_power_off;

static const struct attribute_group *port_dev_group[];

static ssize_t connect_type_show(struct device *dev,
				 struct device_attribute *attr, char *buf)
{
	struct usb_port *port_dev = to_usb_port(dev);
	char *result;

	switch (port_dev->connect_type) {
	case USB_PORT_CONNECT_TYPE_HOT_PLUG:
		result = "hotplug";
		break;
	case USB_PORT_CONNECT_TYPE_HARD_WIRED:
		result = "hardwired";
		break;
	case USB_PORT_NOT_USED:
		result = "not used";
		break;
	default:
		result = "unknown";
		break;
	}

	return sprintf(buf, "%s\n", result);
}
static DEVICE_ATTR_RO(connect_type);

static struct attribute *port_dev_attrs[] = {
	&dev_attr_connect_type.attr,
	NULL,
};

static struct attribute_group port_dev_attr_grp = {
	.attrs = port_dev_attrs,
};

static const struct attribute_group *port_dev_group[] = {
	&port_dev_attr_grp,
	NULL,
};

static void usb_port_device_release(struct device *dev)
{
	struct usb_port *port_dev = to_usb_port(dev);

	kfree(port_dev->req);
	kfree(port_dev);
}

#ifdef CONFIG_PM
static int usb_port_runtime_resume(struct device *dev)
{
	struct usb_port *port_dev = to_usb_port(dev);
	struct usb_device *hdev = to_usb_device(dev->parent->parent);
	struct usb_interface *intf = to_usb_interface(dev->parent);
	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
	struct usb_device *udev = port_dev->child;
	struct usb_port *peer = port_dev->peer;
	int port1 = port_dev->portnum;
	int retval;

	if (!hub)
		return -EINVAL;
	if (hub->in_reset) {
		set_bit(port1, hub->power_bits);
		return 0;
	}

	/*
	 * Power on our usb3 peer before this usb2 port to prevent a usb3
	 * device from degrading to its usb2 connection
	 */
	if (!port_dev->is_superspeed && peer)
		pm_runtime_get_sync(&peer->dev);

	usb_autopm_get_interface(intf);
	retval = usb_hub_set_port_power(hdev, hub, port1, true);
	msleep(hub_power_on_good_delay(hub));
	if (udev && !retval) {
		/*
		 * Our preference is to simply wait for the port to reconnect,
		 * as that is the lowest latency method to restart the port.
		 * However, there are cases where toggling port power results in
		 * the host port and the device port getting out of sync causing
		 * a link training live lock.  Upon timeout, flag the port as
		 * needing warm reset recovery (to be performed later by
		 * usb_port_resume() as requested via usb_wakeup_notification())
		 */
		if (hub_port_debounce_be_connected(hub, port1) < 0) {
			dev_dbg(&port_dev->dev, "reconnect timeout\n");
			if (hub_is_superspeed(hdev))
				set_bit(port1, hub->warm_reset_bits);
		}

		/* Force the child awake to revalidate after the power loss. */
		if (!test_and_set_bit(port1, hub->child_usage_bits)) {
			pm_runtime_get_noresume(&port_dev->dev);
			pm_request_resume(&udev->dev);
		}
	}

	usb_autopm_put_interface(intf);

	return retval;
}

static int usb_port_runtime_suspend(struct device *dev)
{
	struct usb_port *port_dev = to_usb_port(dev);
	struct usb_device *hdev = to_usb_device(dev->parent->parent);
	struct usb_interface *intf = to_usb_interface(dev->parent);
	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
	struct usb_port *peer = port_dev->peer;
	int port1 = port_dev->portnum;
	int retval;

	if (!hub)
		return -EINVAL;
	if (hub->in_reset)
		return -EBUSY;

	if (dev_pm_qos_flags(&port_dev->dev, PM_QOS_FLAG_NO_POWER_OFF)
			== PM_QOS_FLAGS_ALL)
		return -EAGAIN;

	if (usb_port_block_power_off)
		return -EBUSY;

	usb_autopm_get_interface(intf);
	retval = usb_hub_set_port_power(hdev, hub, port1, false);
	usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION);
	if (!port_dev->is_superspeed)
		usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
	usb_autopm_put_interface(intf);

	/*
	 * Our peer usb3 port may now be able to suspend, so
	 * asynchronously queue a suspend request to observe that this
	 * usb2 port is now off.
	 */
	if (!port_dev->is_superspeed && peer)
		pm_runtime_put(&peer->dev);

	return retval;
}
#endif

static const struct dev_pm_ops usb_port_pm_ops = {
#ifdef CONFIG_PM
	.runtime_suspend =	usb_port_runtime_suspend,
	.runtime_resume =	usb_port_runtime_resume,
#endif
};

struct device_type usb_port_device_type = {
	.name =		"usb_port",
	.release =	usb_port_device_release,
	.pm =		&usb_port_pm_ops,
};

static struct device_driver usb_port_driver = {
	.name = "usb",
	.owner = THIS_MODULE,
};

static int link_peers(struct usb_port *left, struct usb_port *right)
{
	struct usb_port *ss_port, *hs_port;
	int rc;

	if (left->peer == right && right->peer == left)
		return 0;

	if (left->peer || right->peer) {
		struct usb_port *lpeer = left->peer;
		struct usb_port *rpeer = right->peer;
		char *method;

		if (left->location && left->location == right->location)
			method = "location";
		else
			method = "default";

		pr_warn("usb: failed to peer %s and %s by %s (%s:%s) (%s:%s)\n",
			dev_name(&left->dev), dev_name(&right->dev), method,
			dev_name(&left->dev),
			lpeer ? dev_name(&lpeer->dev) : "none",
			dev_name(&right->dev),
			rpeer ? dev_name(&rpeer->dev) : "none");
		return -EBUSY;
	}

	rc = sysfs_create_link(&left->dev.kobj, &right->dev.kobj, "peer");
	if (rc)
		return rc;
	rc = sysfs_create_link(&right->dev.kobj, &left->dev.kobj, "peer");
	if (rc) {
		sysfs_remove_link(&left->dev.kobj, "peer");
		return rc;
	}

	/*
	 * We need to wake the HiSpeed port to make sure we don't race
	 * setting ->peer with usb_port_runtime_suspend().  Otherwise we
	 * may miss a suspend event for the SuperSpeed port.
	 */
	if (left->is_superspeed) {
		ss_port = left;
		WARN_ON(right->is_superspeed);
		hs_port = right;
	} else {
		ss_port = right;
		WARN_ON(!right->is_superspeed);
		hs_port = left;
	}
	pm_runtime_get_sync(&hs_port->dev);

	left->peer = right;
	right->peer = left;

	/*
	 * The SuperSpeed reference is dropped when the HiSpeed port in
	 * this relationship suspends, i.e. when it is safe to allow a
	 * SuperSpeed connection to drop since there is no risk of a
	 * device degrading to its powered-off HiSpeed connection.
	 *
	 * Also, drop the HiSpeed ref taken above.
	 */
	pm_runtime_get_sync(&ss_port->dev);
	pm_runtime_put(&hs_port->dev);

	return 0;
}

static void link_peers_report(struct usb_port *left, struct usb_port *right)
{
	int rc;

	rc = link_peers(left, right);
	if (rc == 0) {
		dev_dbg(&left->dev, "peered to %s\n", dev_name(&right->dev));
	} else {
		dev_warn(&left->dev, "failed to peer to %s (%d)\n",
				dev_name(&right->dev), rc);
		pr_warn_once("usb: port power management may be unreliable\n");
		usb_port_block_power_off = 1;
	}
}

static void unlink_peers(struct usb_port *left, struct usb_port *right)
{
	struct usb_port *ss_port, *hs_port;

	WARN(right->peer != left || left->peer != right,
			"%s and %s are not peers?\n",
			dev_name(&left->dev), dev_name(&right->dev));

	/*
	 * We wake the HiSpeed port to make sure we don't race its
	 * usb_port_runtime_resume() event which takes a SuperSpeed ref
	 * when ->peer is !NULL.
	 */
	if (left->is_superspeed) {
		ss_port = left;
		hs_port = right;
	} else {
		ss_port = right;
		hs_port = left;
	}

	pm_runtime_get_sync(&hs_port->dev);

	sysfs_remove_link(&left->dev.kobj, "peer");
	right->peer = NULL;
	sysfs_remove_link(&right->dev.kobj, "peer");
	left->peer = NULL;

	/* Drop the SuperSpeed ref held on behalf of the active HiSpeed port */
	pm_runtime_put(&ss_port->dev);

	/* Drop the ref taken above */
	pm_runtime_put(&hs_port->dev);
}

/*
 * For each usb hub device in the system check to see if it is in the
 * peer domain of the given port_dev, and if it is check to see if it
 * has a port that matches the given port by location
 */
static int match_location(struct usb_device *peer_hdev, void *p)
{
	int port1;
	struct usb_hcd *hcd, *peer_hcd;
	struct usb_port *port_dev = p, *peer;
	struct usb_hub *peer_hub = usb_hub_to_struct_hub(peer_hdev);
	struct usb_device *hdev = to_usb_device(port_dev->dev.parent->parent);

	if (!peer_hub)
		return 0;

	hcd = bus_to_hcd(hdev->bus);
	peer_hcd = bus_to_hcd(peer_hdev->bus);
	/* peer_hcd is provisional until we verify it against the known peer */
	if (peer_hcd != hcd->shared_hcd)
		return 0;

	for (port1 = 1; port1 <= peer_hdev->maxchild; port1++) {
		peer = peer_hub->ports[port1 - 1];
		if (peer && peer->location == port_dev->location) {
			link_peers_report(port_dev, peer);
			return 1; /* done */
		}
	}

	return 0;
}

/*
 * Find the peer port either via explicit platform firmware "location"
 * data, the peer hcd for root hubs, or the upstream peer relationship
 * for all other hubs.
 */
static void find_and_link_peer(struct usb_hub *hub, int port1)
{
	struct usb_port *port_dev = hub->ports[port1 - 1], *peer;
	struct usb_device *hdev = hub->hdev;
	struct usb_device *peer_hdev;
	struct usb_hub *peer_hub;

	/*
	 * If location data is available then we can only peer this port
	 * by a location match, not the default peer (lest we create a
	 * situation where we need to go back and undo a default peering
	 * when the port is later peered by location data)
	 */
	if (port_dev->location) {
		/* we link the peer in match_location() if found */
		usb_for_each_dev(port_dev, match_location);
		return;
	} else if (!hdev->parent) {
		struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
		struct usb_hcd *peer_hcd = hcd->shared_hcd;

		if (!peer_hcd)
			return;

		peer_hdev = peer_hcd->self.root_hub;
	} else {
		struct usb_port *upstream;
		struct usb_device *parent = hdev->parent;
		struct usb_hub *parent_hub = usb_hub_to_struct_hub(parent);

		if (!parent_hub)
			return;

		upstream = parent_hub->ports[hdev->portnum - 1];
		if (!upstream || !upstream->peer)
			return;

		peer_hdev = upstream->peer->child;
	}

	peer_hub = usb_hub_to_struct_hub(peer_hdev);
	if (!peer_hub || port1 > peer_hdev->maxchild)
		return;

	/*
	 * we found a valid default peer, last check is to make sure it
	 * does not have location data
	 */
	peer = peer_hub->ports[port1 - 1];
	if (peer && peer->location == 0)
		link_peers_report(port_dev, peer);
}

int usb_hub_create_port_device(struct usb_hub *hub, int port1)
{
	struct usb_port *port_dev;
	int retval;

	port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
	if (!port_dev)
		return -ENOMEM;

	port_dev->req = kzalloc(sizeof(*(port_dev->req)), GFP_KERNEL);
	if (!port_dev->req) {
		kfree(port_dev);
		return -ENOMEM;
	}

	hub->ports[port1 - 1] = port_dev;
	port_dev->portnum = port1;
	set_bit(port1, hub->power_bits);
	port_dev->dev.parent = hub->intfdev;
	port_dev->dev.groups = port_dev_group;
	port_dev->dev.type = &usb_port_device_type;
	port_dev->dev.driver = &usb_port_driver;
	if (hub_is_superspeed(hub->hdev))
		port_dev->is_superspeed = 1;
	dev_set_name(&port_dev->dev, "%s-port%d", dev_name(&hub->hdev->dev),
			port1);
	mutex_init(&port_dev->status_lock);
	retval = device_register(&port_dev->dev);
	if (retval) {
		put_device(&port_dev->dev);
		return retval;
	}

	/* Set default policy of port-poweroff disabled. */
	retval = dev_pm_qos_add_request(&port_dev->dev, port_dev->req,
			DEV_PM_QOS_FLAGS, PM_QOS_FLAG_NO_POWER_OFF);
	if (retval < 0) {
		device_unregister(&port_dev->dev);
		return retval;
	}

	find_and_link_peer(hub, port1);

	/*
	 * Enable runtime pm and hold a refernce that hub_configure()
	 * will drop once the PM_QOS_NO_POWER_OFF flag state has been set
	 * and the hub has been fully registered (hdev->maxchild set).
	 */
	pm_runtime_set_active(&port_dev->dev);
	pm_runtime_get_noresume(&port_dev->dev);
	pm_runtime_enable(&port_dev->dev);
	device_enable_async_suspend(&port_dev->dev);

	/*
	 * Keep hidden the ability to enable port-poweroff if the hub
	 * does not support power switching.
	 */
	if (!hub_is_port_power_switchable(hub))
		return 0;

	/* Attempt to let userspace take over the policy. */
	retval = dev_pm_qos_expose_flags(&port_dev->dev,
			PM_QOS_FLAG_NO_POWER_OFF);
	if (retval < 0) {
		dev_warn(&port_dev->dev, "failed to expose pm_qos_no_poweroff\n");
		return 0;
	}

	/* Userspace owns the policy, drop the kernel 'no_poweroff' request. */
	retval = dev_pm_qos_remove_request(port_dev->req);
	if (retval >= 0) {
		kfree(port_dev->req);
		port_dev->req = NULL;
	}
	return 0;
}

void usb_hub_remove_port_device(struct usb_hub *hub, int port1)
{
	struct usb_port *port_dev = hub->ports[port1 - 1];
	struct usb_port *peer;

	peer = port_dev->peer;
	if (peer)
		unlink_peers(port_dev, peer);
	device_unregister(&port_dev->dev);
}
Commit	Line	Data
6e30d7cb LT	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
9f7344fb	19	#include <linux/slab.h>
971fcd49	20	#include <linux/pm_qos.h>
9f7344fb	21
6e30d7cb LT	22	#include "hub.h"
6e30d7cb LT	23
6c79fe4a DW	24	static int usb_port_block_power_off;
6c79fe4a DW	25
cef7468c LT	26	static const struct attribute_group *port_dev_group[];
cef7468c LT	27
d03f254f GKH	28	static ssize_t connect_type_show(struct device *dev,
d03f254f GKH	29	struct device_attribute attr, char buf)
cef7468c LT	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	}
d03f254f	51	static DEVICE_ATTR_RO(connect_type);
cef7468c LT	52
	53	static struct attribute *port_dev_attrs[] = {
	54	&dev_attr_connect_type.attr,
	55	NULL,
	56	};
	57
	58	static struct attribute_group port_dev_attr_grp = {
	59	.attrs = port_dev_attrs,
	60	};
	61
	62	static const struct attribute_group *port_dev_group[] = {
	63	&port_dev_attr_grp,
	64	NULL,
	65	};
	66
6e30d7cb LT	67	static void usb_port_device_release(struct device *dev)
	68	{
	69	struct usb_port *port_dev = to_usb_port(dev);
	70
e3d10505	71	kfree(port_dev->req);
6e30d7cb LT	72	kfree(port_dev);
	73	}
	74
ceb6c9c8	75	#ifdef CONFIG_PM
971fcd49 LT	76	static 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);
ad493e5e	81	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
7027df36	82	struct usb_device *udev = port_dev->child;
7ad3c470	83	struct usb_port *peer = port_dev->peer;
ad493e5e	84	int port1 = port_dev->portnum;
971fcd49 LT	85	int retval;
971fcd49 LT	86
ad493e5e LT	87	if (!hub)
ad493e5e LT	88	return -EINVAL;
600856c2	89	if (hub->in_reset) {
d5c3834e	90	set_bit(port1, hub->power_bits);
600856c2 AS	91	return 0;
600856c2 AS	92	}
ad493e5e	93
7ad3c470 DW	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
971fcd49	101	usb_autopm_get_interface(intf);
41341261	102	retval = usb_hub_set_port_power(hdev, hub, port1, true);
7ad3c470	103	msleep(hub_power_on_good_delay(hub));
7027df36	104	if (udev && !retval) {
ad493e5e	105	/*
3cd12f91 DW	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())
ad493e5e	113	*/
3cd12f91 DW	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	}
7027df36 DW	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	}
ad493e5e LT	125	}
ad493e5e LT	126
971fcd49	127	usb_autopm_put_interface(intf);
7ad3c470	128
971fcd49 LT	129	return retval;
	130	}
	131
	132	static 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);
ad493e5e	137	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
7ad3c470	138	struct usb_port *peer = port_dev->peer;
ad493e5e	139	int port1 = port_dev->portnum;
971fcd49 LT	140	int retval;
971fcd49 LT	141
ad493e5e LT	142	if (!hub)
ad493e5e LT	143	return -EINVAL;
600856c2 AS	144	if (hub->in_reset)
600856c2 AS	145	return -EBUSY;
ad493e5e	146
971fcd49 LT	147	if (dev_pm_qos_flags(&port_dev->dev, PM_QOS_FLAG_NO_POWER_OFF)
	148	== PM_QOS_FLAGS_ALL)
	149	return -EAGAIN;
	150
6c79fe4a DW	151	if (usb_port_block_power_off)
	152	return -EBUSY;
	153
971fcd49	154	usb_autopm_get_interface(intf);
41341261	155	retval = usb_hub_set_port_power(hdev, hub, port1, false);
ad493e5e	156	usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION);
69080584 DW	157	if (!port_dev->is_superspeed)
69080584 DW	158	usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
971fcd49	159	usb_autopm_put_interface(intf);
7ad3c470 DW	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
971fcd49 LT	169	return retval;
	170	}
	171	#endif
	172
	173	static const struct dev_pm_ops usb_port_pm_ops = {
ceb6c9c8	174	#ifdef CONFIG_PM
971fcd49 LT	175	.runtime_suspend = usb_port_runtime_suspend,
971fcd49 LT	176	.runtime_resume = usb_port_runtime_resume,
971fcd49 LT	177	#endif
	178	};
	179
6e30d7cb LT	180	struct device_type usb_port_device_type = {
	181	.name = "usb_port",
	182	.release = usb_port_device_release,
971fcd49	183	.pm = &usb_port_pm_ops,
6e30d7cb LT	184	};
6e30d7cb LT	185
d99f6b41 DW	186	static struct device_driver usb_port_driver = {
	187	.name = "usb",
	188	.owner = THIS_MODULE,
	189	};
	190
b7e38eac	191	static int link_peers(struct usb_port left, struct usb_port right)
d8521afe	192	{
7ad3c470	193	struct usb_port ss_port, hs_port;
b7e38eac DW	194	int rc;
b7e38eac DW	195
d8521afe	196	if (left->peer == right && right->peer == left)
b7e38eac	197	return 0;
d8521afe DW	198
	199	if (left->peer \|\| right->peer) {
	200	struct usb_port *lpeer = left->peer;
	201	struct usb_port *rpeer = right->peer;
6c79fe4a DW	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");
b7e38eac DW	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;
d8521afe DW	225	}
d8521afe DW	226
7ad3c470 DW	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
d8521afe DW	243	left->peer = right;
d8521afe DW	244	right->peer = left;
b7e38eac	245
7ad3c470 DW	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
b7e38eac DW	257	return 0;
	258	}
	259
	260	static 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");
6c79fe4a	271	usb_port_block_power_off = 1;
b7e38eac	272	}
d8521afe DW	273	}
	274
	275	static void unlink_peers(struct usb_port left, struct usb_port right)
	276	{
7ad3c470 DW	277	struct usb_port ss_port, hs_port;
7ad3c470 DW	278
d8521afe DW	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
7ad3c470 DW	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
b7e38eac	298	sysfs_remove_link(&left->dev.kobj, "peer");
d8521afe	299	right->peer = NULL;
b7e38eac	300	sysfs_remove_link(&right->dev.kobj, "peer");
d8521afe	301	left->peer = NULL;
7ad3c470 DW	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);
d8521afe DW	308	}
d8521afe DW	309
8b1ba80c	310	/*
3bfd659b DW	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	*/
	315	static 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) {
b7e38eac	335	link_peers_report(port_dev, peer);
3bfd659b DW	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.
8b1ba80c	347	*/
d8521afe DW	348	static 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;
8b1ba80c DW	352	struct usb_device *peer_hdev;
8b1ba80c DW	353	struct usb_hub *peer_hub;
d8521afe	354
3bfd659b DW	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) {
d8521afe DW	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;
8b1ba80c DW	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)
d8521afe DW	379	return;
d8521afe DW	380
8b1ba80c DW	381	upstream = parent_hub->ports[hdev->portnum - 1];
	382	if (!upstream \|\| !upstream->peer)
	383	return;
d8521afe	384
8b1ba80c	385	peer_hdev = upstream->peer->child;
d8521afe	386	}
8b1ba80c DW	387
	388	peer_hub = usb_hub_to_struct_hub(peer_hdev);
	389	if (!peer_hub \|\| port1 > peer_hdev->maxchild)
	390	return;
	391
3bfd659b DW	392	/*
	393	* we found a valid default peer, last check is to make sure it
	394	* does not have location data
	395	*/
8b1ba80c	396	peer = peer_hub->ports[port1 - 1];
3bfd659b	397	if (peer && peer->location == 0)
b7e38eac	398	link_peers_report(port_dev, peer);
d8521afe DW	399	}
d8521afe DW	400
6e30d7cb LT	401	int usb_hub_create_port_device(struct usb_hub *hub, int port1)
6e30d7cb LT	402	{
d8521afe	403	struct usb_port *port_dev;
6e30d7cb LT	404	int retval;
	405
	406	port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
e3d10505 DW	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;
6e30d7cb LT	414	}
	415
	416	hub->ports[port1 - 1] = port_dev;
971fcd49	417	port_dev->portnum = port1;
d5c3834e	418	set_bit(port1, hub->power_bits);
6e30d7cb	419	port_dev->dev.parent = hub->intfdev;
cef7468c	420	port_dev->dev.groups = port_dev_group;
6e30d7cb	421	port_dev->dev.type = &usb_port_device_type;
d99f6b41	422	port_dev->dev.driver = &usb_port_driver;
7ad3c470 DW	423	if (hub_is_superspeed(hub->hdev))
7ad3c470 DW	424	port_dev->is_superspeed = 1;
d99f6b41 DW	425	dev_set_name(&port_dev->dev, "%s-port%d", dev_name(&hub->hdev->dev),
d99f6b41 DW	426	port1);
5c79a1e3	427	mutex_init(&port_dev->status_lock);
6e30d7cb	428	retval = device_register(&port_dev->dev);
e3d10505 DW	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	}
6e30d7cb	441
d8521afe DW	442	find_and_link_peer(hub, port1);
d8521afe DW	443
e3d10505 DW	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	*/
971fcd49	449	pm_runtime_set_active(&port_dev->dev);
e3d10505 DW	450	pm_runtime_get_noresume(&port_dev->dev);
	451	pm_runtime_enable(&port_dev->dev);
	452	device_enable_async_suspend(&port_dev->dev);
f6cced1a	453
9262c19d	454	/*
e3d10505 DW	455	* Keep hidden the ability to enable port-poweroff if the hub
e3d10505 DW	456	* does not support power switching.
f6cced1a	457	*/
e3d10505 DW	458	if (!hub_is_port_power_switchable(hub))
e3d10505 DW	459	return 0;
f6cced1a	460
e3d10505 DW	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	}
6e30d7cb	468
e3d10505 DW	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;
6e30d7cb LT	476	}
6e30d7cb LT	477
d8521afe	478	void usb_hub_remove_port_device(struct usb_hub *hub, int port1)
6e30d7cb	479	{
d8521afe DW	480	struct usb_port *port_dev = hub->ports[port1 - 1];
d8521afe DW	481	struct usb_port *peer;
6e30d7cb	482
d8521afe DW	483	peer = port_dev->peer;
	484	if (peer)
	485	unlink_peers(port_dev, peer);
	486	device_unregister(&port_dev->dev);
	487	}