drivers/usb/host/usb-uclass.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2015 Google, Inc
 * Written by Simon Glass <sjg@chromium.org>
 *
 * usb_match_device() modified from Linux kernel v4.0.
 */

#define LOG_CATEGORY UCLASS_USB

#include <bootdev.h>
#include <uthread.h>
#include <dm.h>
#include <errno.h>
#include <log.h>
#include <memalign.h>
#include <usb.h>
#include <dm/device-internal.h>
#include <dm/lists.h>
#include <dm/uclass-internal.h>
#include <time.h>

static bool asynch_allowed;

struct usb_uclass_priv {
	int companion_device_count;
};

int usb_lock_async(struct usb_device *udev, int lock)
{
	struct udevice *bus = udev->controller_dev;
	struct dm_usb_ops *ops = usb_get_ops(bus);

	if (!ops->lock_async)
		return -ENOSYS;

	return ops->lock_async(bus, lock);
}

int usb_disable_asynch(int disable)
{
	int old_value = asynch_allowed;

	asynch_allowed = !disable;
	return old_value;
}

int submit_int_msg(struct usb_device *udev, unsigned long pipe, void *buffer,
		   int length, int interval, bool nonblock)
{
	struct udevice *bus = udev->controller_dev;
	struct dm_usb_ops *ops = usb_get_ops(bus);

	if (!ops->interrupt)
		return -ENOSYS;

	return ops->interrupt(bus, udev, pipe, buffer, length, interval,
			      nonblock);
}

int submit_control_msg(struct usb_device *udev, unsigned long pipe,
		       void *buffer, int length, struct devrequest *setup)
{
	struct udevice *bus = udev->controller_dev;
	struct dm_usb_ops *ops = usb_get_ops(bus);
	struct usb_uclass_priv *uc_priv = uclass_get_priv(bus->uclass);
	int err;

	if (!ops->control)
		return -ENOSYS;

	err = ops->control(bus, udev, pipe, buffer, length, setup);
	if (setup->request == USB_REQ_SET_FEATURE &&
	    setup->requesttype == USB_RT_PORT &&
	    setup->value == cpu_to_le16(USB_PORT_FEAT_RESET) &&
	    err == -ENXIO) {
		/* Device handed over to companion after port reset */
		uc_priv->companion_device_count++;
	}

	return err;
}

int submit_bulk_msg(struct usb_device *udev, unsigned long pipe, void *buffer,
		    int length)
{
	struct udevice *bus = udev->controller_dev;
	struct dm_usb_ops *ops = usb_get_ops(bus);

	if (!ops->bulk)
		return -ENOSYS;

	return ops->bulk(bus, udev, pipe, buffer, length);
}

struct int_queue *create_int_queue(struct usb_device *udev,
		unsigned long pipe, int queuesize, int elementsize,
		void *buffer, int interval)
{
	struct udevice *bus = udev->controller_dev;
	struct dm_usb_ops *ops = usb_get_ops(bus);

	if (!ops->create_int_queue)
		return NULL;

	return ops->create_int_queue(bus, udev, pipe, queuesize, elementsize,
				     buffer, interval);
}

void *poll_int_queue(struct usb_device *udev, struct int_queue *queue)
{
	struct udevice *bus = udev->controller_dev;
	struct dm_usb_ops *ops = usb_get_ops(bus);

	if (!ops->poll_int_queue)
		return NULL;

	return ops->poll_int_queue(bus, udev, queue);
}

int destroy_int_queue(struct usb_device *udev, struct int_queue *queue)
{
	struct udevice *bus = udev->controller_dev;
	struct dm_usb_ops *ops = usb_get_ops(bus);

	if (!ops->destroy_int_queue)
		return -ENOSYS;

	return ops->destroy_int_queue(bus, udev, queue);
}

int usb_alloc_device(struct usb_device *udev)
{
	struct udevice *bus = udev->controller_dev;
	struct dm_usb_ops *ops = usb_get_ops(bus);

	/* This is only requird by some controllers - current XHCI */
	if (!ops->alloc_device)
		return 0;

	return ops->alloc_device(bus, udev);
}

int usb_reset_root_port(struct usb_device *udev)
{
	struct udevice *bus = udev->controller_dev;
	struct dm_usb_ops *ops = usb_get_ops(bus);

	if (!ops->reset_root_port)
		return -ENOSYS;

	return ops->reset_root_port(bus, udev);
}

int usb_update_hub_device(struct usb_device *udev)
{
	struct udevice *bus = udev->controller_dev;
	struct dm_usb_ops *ops = usb_get_ops(bus);

	if (!ops->update_hub_device)
		return -ENOSYS;

	return ops->update_hub_device(bus, udev);
}

int usb_get_max_xfer_size(struct usb_device *udev, size_t *size)
{
	struct udevice *bus = udev->controller_dev;
	struct dm_usb_ops *ops = usb_get_ops(bus);

	if (!ops->get_max_xfer_size)
		return -ENOSYS;

	return ops->get_max_xfer_size(bus, size);
}

#if CONFIG_IS_ENABLED(UTHREAD)
static struct uthread_mutex mutex = UTHREAD_MUTEX_INITIALIZER;
#endif

int usb_stop(void)
{
	struct udevice *bus;
	struct udevice *rh;
	struct uclass *uc;
	struct usb_uclass_priv *uc_priv;
	int err = 0, ret;

	uthread_mutex_lock(&mutex);

	/* De-activate any devices that have been activated */
	ret = uclass_get(UCLASS_USB, &uc);
	if (ret) {
		uthread_mutex_unlock(&mutex);
		return ret;
	}

	uc_priv = uclass_get_priv(uc);

	uclass_foreach_dev(bus, uc) {
		ret = device_remove(bus, DM_REMOVE_NORMAL);
		if (ret && !err)
			err = ret;

		/* Locate root hub device */
		device_find_first_child(bus, &rh);
		if (rh) {
			/*
			 * All USB devices are children of root hub.
			 * Unbinding root hub will unbind all of its children.
			 */
			ret = device_unbind(rh);
			if (ret && !err)
				err = ret;
		}
	}

#ifdef CONFIG_USB_STORAGE
	usb_stor_reset();
#endif
	if (CONFIG_IS_ENABLED(BOOTSTD)) {
		int ret;

		ret = bootdev_unhunt(UCLASS_USB);
		if (IS_ENABLED(CONFIG_BOOTSTD_FULL) && ret && ret != -EALREADY)
			printf("failed to unhunt USB (err=%dE)\n", ret);
	}
	uc_priv->companion_device_count = 0;
	usb_started = 0;

	uthread_mutex_unlock(&mutex);

	return err;
}

static void _usb_scan_bus(void *arg)
{
	struct udevice *bus = (struct udevice *)arg;
	struct usb_bus_priv *priv;
	struct udevice *dev;
	int ret;

	priv = dev_get_uclass_priv(bus);

	ret = usb_scan_device(bus, 0, USB_SPEED_FULL, &dev);
	if (ret)
		printf("Scanning bus %s failed, error %d\n", bus->name, ret);
}

static void remove_inactive_children(struct uclass *uc, struct udevice *bus)
{
	uclass_foreach_dev(bus, uc) {
		struct udevice *dev, *next;

		if (!device_active(bus))
			continue;
		device_foreach_child_safe(dev, next, bus) {
			if (!device_active(dev))
				device_unbind(dev);
		}
	}
}

static int usb_probe_companion(struct udevice *bus)
{
	struct udevice *companion_dev;
	int ret;

	/*
	 * Enforce optional companion controller is marked as such in order to
	 * 1st scan the primary controller, before the companion controller
	 * (ownership is given to companion when low or full speed devices
	 * have been detected).
	 */
	ret = uclass_get_device_by_phandle(UCLASS_USB, bus, "companion", &companion_dev);
	if (!ret) {
		struct usb_bus_priv *companion_bus_priv;

		debug("%s is the companion of %s\n", companion_dev->name, bus->name);
		companion_bus_priv = dev_get_uclass_priv(companion_dev);
		companion_bus_priv->companion = true;
	} else if (ret && ret != -ENOENT && ret != -ENODEV) {
		/*
		 * Treat everything else than no companion or disabled
		 * companion as an error. (It may not be enabled on boards
		 * that have a High-Speed HUB to handle FS and LS traffic).
		 */
		printf("Failed to get companion (ret=%d)\n", ret);
		return ret;
	}

	return 0;
}

static void _usb_init_bus(void *arg)
{
	struct udevice *bus = (struct udevice *)arg;
	int ret;

	/* init low_level USB */

	/*
	 * For Sandbox, we need scan the device tree each time when we
	 * start the USB stack, in order to re-create the emulated USB
	 * devices and bind drivers for them before we actually do the
	 * driver probe.
	 *
	 * For USB onboard HUB, we need to do some non-trivial init
	 * like enabling a power regulator, before enumeration.
	 */
	if (IS_ENABLED(CONFIG_SANDBOX) ||
	    IS_ENABLED(CONFIG_USB_ONBOARD_HUB)) {
		ret = dm_scan_fdt_dev(bus);
		if (ret) {
			printf("Bus %s: USB device scan from fdt failed (%d)\n",
			       bus->name, ret);
			return;
		}
	}

	ret = device_probe(bus);
	if (ret == -ENODEV) {	/* No such device. */
		printf("Bus %s: Port not available.\n", bus->name);
		return;
	}

	if (ret) {		/* Other error. */
		printf("Bus %s: probe failed, error %d\n", bus->name, ret);
		return;
	}

	usb_probe_companion(bus);
}

static int nthr;
static int grp_id;

static void usb_init_bus(struct udevice *bus)
{
	if (!grp_id)
		grp_id = uthread_grp_new_id();
	if (!uthread_create(NULL, _usb_init_bus, (void *)bus, 0, grp_id))
		nthr++;
}

static void usb_scan_bus(struct udevice *bus, bool recurse)
{
	if (!grp_id)
		grp_id = uthread_grp_new_id();
	if (!uthread_create(NULL, _usb_scan_bus, (void *)bus, 0, grp_id))
		nthr++;
}

static void usb_report_devices(struct uclass *uc)
{
	struct usb_bus_priv *priv;
	struct udevice *bus;

	uclass_foreach_dev(bus, uc) {
		if (!device_active(bus))
			continue;
		priv = dev_get_uclass_priv(bus);
		printf("Bus %s: ", bus->name);
		if (priv->next_addr == 0)
			printf("No USB Device found\n");
		else
			printf("%d USB Device(s) found\n", priv->next_addr);
	}
}

static void run_threads(void)
{
#if CONFIG_IS_ENABLED(UTHREAD)
	if (!nthr)
		return;
	while (!uthread_grp_done(grp_id))
		uthread_schedule();
	nthr = 0;
	grp_id = 0;
#endif
}

int usb_init(void)
{
	int controllers_initialized = 0;
	unsigned long t0 = timer_get_us();
	struct usb_uclass_priv *uc_priv;
	struct usb_bus_priv *priv;
	struct udevice *bus;
	struct uclass *uc;
	int ret;

	uthread_mutex_lock(&mutex);

	if (usb_started) {
		ret = 0;
		goto out;
	}

	asynch_allowed = 1;

	ret = uclass_get(UCLASS_USB, &uc);
	if (ret)
		goto out;

	uc_priv = uclass_get_priv(uc);

	uclass_foreach_dev(bus, uc) {
		usb_init_bus(bus);
	}

	if (CONFIG_IS_ENABLED(UTHREAD))
		run_threads();

	usb_started = true;

	/*
	 * lowlevel init done, now scan the bus for devices i.e. search HUBs
	 * and configure them, first scan primary controllers.
	 */
	uclass_foreach_dev(bus, uc) {
		if (!device_active(bus))
			continue;

		controllers_initialized++;

		priv = dev_get_uclass_priv(bus);
		if (!priv->companion)
			usb_scan_bus(bus, true);
	}

	if (CONFIG_IS_ENABLED(UTHREAD))
		run_threads();

	/*
	 * Now that the primary controllers have been scanned and have handed
	 * over any devices they do not understand to their companions, scan
	 * the companions if necessary.
	 */
	if (uc_priv->companion_device_count) {
		uclass_foreach_dev(bus, uc) {
			if (!device_active(bus))
				continue;

			priv = dev_get_uclass_priv(bus);
			if (priv->companion)
				usb_scan_bus(bus, true);
		}
	}

	if (CONFIG_IS_ENABLED(UTHREAD))
		run_threads();

	usb_report_devices(uc);

	/* Remove any devices that were not found on this scan */
	remove_inactive_children(uc, bus);

	ret = uclass_get(UCLASS_USB_HUB, &uc);
	if (ret)
		goto out;

	remove_inactive_children(uc, bus);

	/* if we were not able to find at least one working bus, bail out */
	if (controllers_initialized == 0)
		printf("No USB controllers found\n");

	debug("USB initialized in %ld ms\n",
	      (timer_get_us() - t0) / 1000);

	uthread_mutex_unlock(&mutex);

	return usb_started ? 0 : -ENOENT;
out:
	uthread_mutex_unlock(&mutex);

	return ret;
}

int usb_setup_ehci_gadget(struct ehci_ctrl **ctlrp)
{
	struct usb_plat *plat;
	struct udevice *dev;
	int ret;

	/* Find the old device and remove it */
	ret = uclass_find_first_device(UCLASS_USB, &dev);
	if (ret)
		return ret;
	ret = device_remove(dev, DM_REMOVE_NORMAL);
	if (ret)
		return ret;

	plat = dev_get_plat(dev);
	plat->init_type = USB_INIT_DEVICE;
	ret = device_probe(dev);
	if (ret)
		return ret;
	*ctlrp = dev_get_priv(dev);

	return 0;
}

int usb_remove_ehci_gadget(struct ehci_ctrl **ctlrp)
{
	struct udevice *dev;
	int ret;

	/* Find the old device and remove it */
	ret = uclass_find_first_device(UCLASS_USB, &dev);
	if (ret)
		return ret;
	ret = device_remove(dev, DM_REMOVE_NORMAL);
	if (ret)
		return ret;

	*ctlrp = NULL;

	return 0;
}

/* returns 0 if no match, 1 if match */
static int usb_match_device(const struct usb_device_descriptor *desc,
			    const struct usb_device_id *id)
{
	if ((id->match_flags & USB_DEVICE_ID_MATCH_VENDOR) &&
	    id->idVendor != desc->idVendor)
		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_PRODUCT) &&
	    id->idProduct != desc->idProduct)
		return 0;

	/* No need to test id->bcdDevice_lo != 0, since 0 is never
	   greater than any unsigned number. */
	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_LO) &&
	    (id->bcdDevice_lo > desc->bcdDevice))
		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_HI) &&
	    (id->bcdDevice_hi < desc->bcdDevice))
		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_CLASS) &&
	    (id->bDeviceClass != desc->bDeviceClass))
		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_SUBCLASS) &&
	    (id->bDeviceSubClass != desc->bDeviceSubClass))
		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_DEV_PROTOCOL) &&
	    (id->bDeviceProtocol != desc->bDeviceProtocol))
		return 0;

	return 1;
}

/* returns 0 if no match, 1 if match */
static int usb_match_one_id_intf(const struct usb_device_descriptor *desc,
			const struct usb_interface_descriptor *int_desc,
			const struct usb_device_id *id)
{
	/* The interface class, subclass, protocol and number should never be
	 * checked for a match if the device class is Vendor Specific,
	 * unless the match record specifies the Vendor ID. */
	if (desc->bDeviceClass == USB_CLASS_VENDOR_SPEC &&
	    !(id->match_flags & USB_DEVICE_ID_MATCH_VENDOR) &&
	    (id->match_flags & (USB_DEVICE_ID_MATCH_INT_CLASS |
				USB_DEVICE_ID_MATCH_INT_SUBCLASS |
				USB_DEVICE_ID_MATCH_INT_PROTOCOL |
				USB_DEVICE_ID_MATCH_INT_NUMBER)))
		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_CLASS) &&
	    (id->bInterfaceClass != int_desc->bInterfaceClass))
		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_SUBCLASS) &&
	    (id->bInterfaceSubClass != int_desc->bInterfaceSubClass))
		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_PROTOCOL) &&
	    (id->bInterfaceProtocol != int_desc->bInterfaceProtocol))
		return 0;

	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_NUMBER) &&
	    (id->bInterfaceNumber != int_desc->bInterfaceNumber))
		return 0;

	return 1;
}

/* returns 0 if no match, 1 if match */
static int usb_match_one_id(struct usb_device_descriptor *desc,
			    struct usb_interface_descriptor *int_desc,
			    const struct usb_device_id *id)
{
	if (!usb_match_device(desc, id))
		return 0;

	return usb_match_one_id_intf(desc, int_desc, id);
}

static ofnode usb_get_ofnode(struct udevice *hub, int port)
{
	ofnode node;
	u32 reg;

	if (!dev_has_ofnode(hub))
		return ofnode_null();

	/*
	 * The USB controller and its USB hub are two different udevices,
	 * but the device tree has only one node for both. Thus we are
	 * assigning this node to both udevices.
	 * If port is zero, the controller scans its root hub, thus we
	 * are using the same ofnode as the controller here.
	 */
	if (!port)
		return dev_ofnode(hub);

	ofnode_for_each_subnode(node, dev_ofnode(hub)) {
		if (ofnode_read_u32(node, "reg", &reg))
			continue;

		if (reg == port)
			return node;
	}

	return ofnode_null();
}

/**
 * usb_find_and_bind_driver() - Find and bind the right USB driver
 *
 * This only looks at certain fields in the descriptor.
 */
static int usb_find_and_bind_driver(struct udevice *parent,
				    struct usb_device_descriptor *desc,
				    struct usb_interface_descriptor *iface,
				    int bus_seq, int devnum, int port,
				    struct udevice **devp)
{
	struct usb_driver_entry *start, *entry;
	int n_ents;
	int ret;
	char name[34], *str;
	ofnode node = usb_get_ofnode(parent, port);

	*devp = NULL;
	debug("%s: Searching for driver\n", __func__);
	start = ll_entry_start(struct usb_driver_entry, usb_driver_entry);
	n_ents = ll_entry_count(struct usb_driver_entry, usb_driver_entry);
	for (entry = start; entry != start + n_ents; entry++) {
		const struct usb_device_id *id;
		struct udevice *dev;
		const struct driver *drv;
		struct usb_dev_plat *plat;

		for (id = entry->match; id->match_flags; id++) {
			if (!usb_match_one_id(desc, iface, id))
				continue;

			drv = entry->driver;
			/*
			 * We could pass the descriptor to the driver as
			 * plat (instead of NULL) and allow its bind()
			 * method to return -ENOENT if it doesn't support this
			 * device. That way we could continue the search to
			 * find another driver. For now this doesn't seem
			 * necesssary, so just bind the first match.
			 */
			ret = device_bind(parent, drv, drv->name, NULL, node,
					  &dev);
			if (ret)
				goto error;
			debug("%s: Match found: %s\n", __func__, drv->name);
			dev->driver_data = id->driver_info;
			plat = dev_get_parent_plat(dev);
			plat->id = *id;
			*devp = dev;
			return 0;
		}
	}

	/* Bind a generic driver so that the device can be used */
	snprintf(name, sizeof(name), "generic_bus_%x_dev_%x", bus_seq, devnum);
	str = strdup(name);
	if (!str)
		return -ENOMEM;
	ret = device_bind_driver(parent, "usb_dev_generic_drv", str, devp);
	if (!ret)
		device_set_name_alloced(*devp);

error:
	debug("%s: No match found: %d\n", __func__, ret);
	return ret;
}

/**
 * usb_find_child() - Find an existing device which matches our needs
 *
 *
 */
static int usb_find_child(struct udevice *parent,
			  struct usb_device_descriptor *desc,
			  struct usb_interface_descriptor *iface,
			  struct udevice **devp)
{
	struct udevice *dev;

	*devp = NULL;
	for (device_find_first_child(parent, &dev);
	     dev;
	     device_find_next_child(&dev)) {
		struct usb_dev_plat *plat = dev_get_parent_plat(dev);

		/* If this device is already in use, skip it */
		if (device_active(dev))
			continue;
		debug("   %s: name='%s', plat=%d, desc=%d\n", __func__,
		      dev->name, plat->id.bDeviceClass, desc->bDeviceClass);
		if (usb_match_one_id(desc, iface, &plat->id)) {
			*devp = dev;
			return 0;
		}
	}

	return -ENOENT;
}

int usb_scan_device(struct udevice *parent, int port,
		    enum usb_device_speed speed, struct udevice **devp)
{
	struct udevice *dev;
	bool created = false;
	struct usb_dev_plat *plat;
	struct usb_bus_priv *priv;
	struct usb_device *parent_udev;
	int ret;
	ALLOC_CACHE_ALIGN_BUFFER(struct usb_device, udev, 1);
	struct usb_interface_descriptor *iface = &udev->config.if_desc[0].desc;

	*devp = NULL;
	memset(udev, '\0', sizeof(*udev));
	udev->controller_dev = usb_get_bus(parent);
	priv = dev_get_uclass_priv(udev->controller_dev);

	/*
	 * Somewhat nasty, this. We create a local device and use the normal
	 * USB stack to read its descriptor. Then we know what type of device
	 * to create for real.
	 *
	 * udev->dev is set to the parent, since we don't have a real device
	 * yet. The USB stack should not access udev.dev anyway, except perhaps
	 * to find the controller, and the controller will either be @parent,
	 * or some parent of @parent.
	 *
	 * Another option might be to create the device as a generic USB
	 * device, then morph it into the correct one when we know what it
	 * should be. This means that a generic USB device would morph into
	 * a network controller, or a USB flash stick, for example. However,
	 * we don't support such morphing and it isn't clear that it would
	 * be easy to do.
	 *
	 * Yet another option is to split out the USB stack parts of udev
	 * into something like a 'struct urb' (as Linux does) which can exist
	 * independently of any device. This feels cleaner, but calls for quite
	 * a big change to the USB stack.
	 *
	 * For now, the approach is to set up an empty udev, read its
	 * descriptor and assign it an address, then bind a real device and
	 * stash the resulting information into the device's parent
	 * platform data. Then when we probe it, usb_child_pre_probe() is called
	 * and it will pull the information out of the stash.
	 */
	udev->dev = parent;
	udev->speed = speed;
	udev->devnum = priv->next_addr + 1;
	udev->portnr = port;
	debug("Calling usb_setup_device(), portnr=%d\n", udev->portnr);
	parent_udev = device_get_uclass_id(parent) == UCLASS_USB_HUB ?
		dev_get_parent_priv(parent) : NULL;
	ret = usb_setup_device(udev, priv->desc_before_addr, parent_udev);
	debug("read_descriptor for '%s': ret=%d\n", parent->name, ret);
	if (ret)
		return ret;
	ret = usb_find_child(parent, &udev->descriptor, iface, &dev);
	debug("** usb_find_child returns %d\n", ret);
	if (ret) {
		if (ret != -ENOENT)
			return ret;
		ret = usb_find_and_bind_driver(parent, &udev->descriptor,
					       iface,
					       dev_seq(udev->controller_dev),
					       udev->devnum, port, &dev);
		if (ret)
			return ret;
		created = true;
	}
	plat = dev_get_parent_plat(dev);
	debug("%s: Probing '%s', plat=%p\n", __func__, dev->name, plat);
	plat->devnum = udev->devnum;
	plat->udev = udev;
	priv->next_addr++;
	ret = device_probe(dev);
	if (ret) {
		debug("%s: Device '%s' probe failed\n", __func__, dev->name);
		priv->next_addr--;
		if (created)
			device_unbind(dev);
		return ret;
	}
	*devp = dev;

	return 0;
}

/*
 * Detect if a USB device has been plugged or unplugged.
 */
int usb_detect_change(void)
{
	struct udevice *hub;
	struct uclass *uc;
	int change = 0;
	int ret;

	ret = uclass_get(UCLASS_USB_HUB, &uc);
	if (ret)
		return ret;

	uclass_foreach_dev(hub, uc) {
		struct usb_device *udev;
		struct udevice *dev;

		if (!device_active(hub))
			continue;
		for (device_find_first_child(hub, &dev);
		     dev;
		     device_find_next_child(&dev)) {
			struct usb_port_status status;

			if (!device_active(dev))
				continue;

			udev = dev_get_parent_priv(dev);
			if (usb_get_port_status(udev, udev->portnr, &status)
					< 0)
				/* USB request failed */
				continue;

			if (le16_to_cpu(status.wPortChange) &
			    USB_PORT_STAT_C_CONNECTION)
				change++;
		}
	}

	return change;
}

static int usb_child_post_bind(struct udevice *dev)
{
	struct usb_dev_plat *plat = dev_get_parent_plat(dev);
	int val;

	if (!dev_has_ofnode(dev))
		return 0;

	/* We only support matching a few things */
	val = dev_read_u32_default(dev, "usb,device-class", -1);
	if (val != -1) {
		plat->id.match_flags |= USB_DEVICE_ID_MATCH_DEV_CLASS;
		plat->id.bDeviceClass = val;
	}
	val = dev_read_u32_default(dev, "usb,interface-class", -1);
	if (val != -1) {
		plat->id.match_flags |= USB_DEVICE_ID_MATCH_INT_CLASS;
		plat->id.bInterfaceClass = val;
	}

	return 0;
}

struct udevice *usb_get_bus(struct udevice *dev)
{
	struct udevice *bus;

	for (bus = dev; bus && device_get_uclass_id(bus) != UCLASS_USB; )
		bus = bus->parent;
	if (!bus) {
		/* By design this cannot happen */
		assert(bus);
		debug("USB HUB '%s' does not have a controller\n", dev->name);
	}

	return bus;
}

int usb_child_pre_probe(struct udevice *dev)
{
	struct usb_device *udev = dev_get_parent_priv(dev);
	struct usb_dev_plat *plat = dev_get_parent_plat(dev);
	int ret;

	if (plat->udev) {
		/*
		 * Copy over all the values set in the on stack struct
		 * usb_device in usb_scan_device() to our final struct
		 * usb_device for this dev.
		 */
		*udev = *(plat->udev);
		/* And clear plat->udev as it will not be valid for long */
		plat->udev = NULL;
		udev->dev = dev;
	} else {
		/*
		 * This happens with devices which are explicitly bound
		 * instead of being discovered through usb_scan_device()
		 * such as sandbox emul devices.
		 */
		udev->dev = dev;
		udev->controller_dev = usb_get_bus(dev);
		udev->devnum = plat->devnum;

		/*
		 * udev did not go through usb_scan_device(), so we need to
		 * select the config and read the config descriptors.
		 */
		ret = usb_select_config(udev);
		if (ret)
			return ret;
	}

	return 0;
}

UCLASS_DRIVER(usb) = {
	.id		= UCLASS_USB,
	.name		= "usb",
	.flags		= DM_UC_FLAG_SEQ_ALIAS,
	.post_bind	= dm_scan_fdt_dev,
	.priv_auto	= sizeof(struct usb_uclass_priv),
	.per_child_auto	= sizeof(struct usb_device),
	.per_device_auto	= sizeof(struct usb_bus_priv),
	.child_post_bind = usb_child_post_bind,
	.child_pre_probe = usb_child_pre_probe,
	.per_child_plat_auto	= sizeof(struct usb_dev_plat),
};

UCLASS_DRIVER(usb_dev_generic) = {
	.id		= UCLASS_USB_DEV_GENERIC,
	.name		= "usb_dev_generic",
};

U_BOOT_DRIVER(usb_dev_generic_drv) = {
	.id		= UCLASS_USB_DEV_GENERIC,
	.name		= "usb_dev_generic_drv",
};