// SPDX-License-Identifier: GPL-2.0+

  /*

   * Most of this source has been derived from the Linux USB
   * project:
   * (C) Copyright Linus Torvalds 1999
   * (C) Copyright Johannes Erdfelt 1999-2001
   * (C) Copyright Andreas Gal 1999
   * (C) Copyright Gregory P. Smith 1999
   * (C) Copyright Deti Fliegl 1999 (new USB architecture)
   * (C) Copyright Randy Dunlap 2000
   * (C) Copyright David Brownell 2000 (kernel hotplug, usb_device_id)
   * (C) Copyright Yggdrasil Computing, Inc. 2000
   *     (usb_device_id matching changes by Adam J. Richter)
   *
   * Adapted for U-Boot:
   * (C) Copyright 2001 Denis Peter, MPL AG Switzerland

   */
  
  /****************************************************************************
   * HUB "Driver"
   * Probes device for being a hub and configurate it
   */
  
  #include <common.h>
  #include <command.h>

  #include <dm.h>

  #include <env.h>

  #include <errno.h>

  #include <malloc.h>

  #include <memalign.h>

  #include <asm/processor.h>

  #include <asm/unaligned.h>

  #include <linux/ctype.h>

  #include <linux/list.h>

  #include <asm/byteorder.h>

  #ifdef CONFIG_SANDBOX
  #include <asm/state.h>
  #endif

  #include <asm/unaligned.h>

  #include <usb.h>

  #define USB_BUFSIZ	512

  #define HUB_SHORT_RESET_TIME	20
  #define HUB_LONG_RESET_TIME	200

  #define PORT_OVERCURRENT_MAX_SCAN_COUNT		3
  
  struct usb_device_scan {
  	struct usb_device *dev;		/* USB hub device to scan */
  	struct usb_hub_device *hub;	/* USB hub struct */
  	int port;			/* USB port to scan */
  	struct list_head list;
  };

  static LIST_HEAD(usb_scan_list);

  __weak void usb_hub_reset_devices(struct usb_hub_device *hub, int port)

  {
  	return;
  }

  static inline bool usb_hub_is_superspeed(struct usb_device *hdev)
  {
  	return hdev->descriptor.bDeviceProtocol == 3;
  }

  #if CONFIG_IS_ENABLED(DM_USB)

  bool usb_hub_is_root_hub(struct udevice *hub)
  {
  	if (device_get_uclass_id(hub->parent) != UCLASS_USB_HUB)
  		return true;
  
  	return false;
  }

  
  static int usb_set_hub_depth(struct usb_device *dev, int depth)
  {
  	if (depth < 0 || depth > 4)
  		return -EINVAL;
  
  	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
  		USB_REQ_SET_HUB_DEPTH, USB_DIR_OUT | USB_RT_HUB,
  		depth, 0, NULL, 0, USB_CNTL_TIMEOUT);
  }

  #endif

  static int usb_get_hub_descriptor(struct usb_device *dev, void *data, int size)
  {

  	unsigned short dtype = USB_DT_HUB;
  
  	if (usb_hub_is_superspeed(dev))
  		dtype = USB_DT_SS_HUB;

  	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
  		USB_REQ_GET_DESCRIPTOR, USB_DIR_IN | USB_RT_HUB,

  		dtype << 8, 0, data, size, USB_CNTL_TIMEOUT);

  }
  
  static int usb_clear_port_feature(struct usb_device *dev, int port, int feature)
  {
  	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
  				USB_REQ_CLEAR_FEATURE, USB_RT_PORT, feature,
  				port, NULL, 0, USB_CNTL_TIMEOUT);
  }
  
  static int usb_set_port_feature(struct usb_device *dev, int port, int feature)
  {
  	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
  				USB_REQ_SET_FEATURE, USB_RT_PORT, feature,
  				port, NULL, 0, USB_CNTL_TIMEOUT);
  }
  
  static int usb_get_hub_status(struct usb_device *dev, void *data)
  {
  	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
  			USB_REQ_GET_STATUS, USB_DIR_IN | USB_RT_HUB, 0, 0,
  			data, sizeof(struct usb_hub_status), USB_CNTL_TIMEOUT);
  }

  int usb_get_port_status(struct usb_device *dev, int port, void *data)

  {

  	int ret;
  
  	ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),

  			USB_REQ_GET_STATUS, USB_DIR_IN | USB_RT_PORT, 0, port,

  			data, sizeof(struct usb_port_status), USB_CNTL_TIMEOUT);

  #if CONFIG_IS_ENABLED(DM_USB)

  	if (ret < 0)
  		return ret;
  
  	/*
  	 * Translate the USB 3.0 hub port status field into the old version
  	 * that U-Boot understands. Do this only when the hub is not root hub.
  	 * For root hub, the port status field has already been translated
  	 * in the host controller driver (see xhci_submit_root() in xhci.c).
  	 *
  	 * Note: this only supports driver model.
  	 */
  
  	if (!usb_hub_is_root_hub(dev->dev) && usb_hub_is_superspeed(dev)) {
  		struct usb_port_status *status = (struct usb_port_status *)data;
  		u16 tmp = (status->wPortStatus) & USB_SS_PORT_STAT_MASK;
  
  		if (status->wPortStatus & USB_SS_PORT_STAT_POWER)
  			tmp |= USB_PORT_STAT_POWER;
  		if ((status->wPortStatus & USB_SS_PORT_STAT_SPEED) ==
  		    USB_SS_PORT_STAT_SPEED_5GBPS)
  			tmp |= USB_PORT_STAT_SUPER_SPEED;
  
  		status->wPortStatus = tmp;
  	}
  #endif
  
  	return ret;

  }
  
  
  static void usb_hub_power_on(struct usb_hub_device *hub)
  {
  	int i;
  	struct usb_device *dev;

  	unsigned pgood_delay = hub->desc.bPwrOn2PwrGood * 2;

  	const char *env;

  
  	dev = hub->pusb_dev;

  	debug("enabling power on all ports
  ");

  	for (i = 0; i < dev->maxchild; i++) {
  		usb_set_port_feature(dev, i + 1, USB_PORT_FEAT_POWER);

  		debug("port %d returns %lX
  ", i + 1, dev->status);

  	}

  #ifdef CONFIG_SANDBOX
  	/*
  	 * Don't set timeout / delay values here. This results
  	 * in these values still being reset to 0.
  	 */
  	if (state_get_skip_delays())
  		return;
  #endif

  	/*
  	 * Wait for power to become stable,
  	 * plus spec-defined max time for device to connect

  	 * but allow this time to be increased via env variable as some
  	 * devices break the spec and require longer warm-up times

  	 */

  	env = env_get("usb_pgood_delay");

  	if (env)
  		pgood_delay = max(pgood_delay,
  			          (unsigned)simple_strtol(env, NULL, 0));
  	debug("pgood_delay=%dms
  ", pgood_delay);

  
  	/*
  	 * Do a minimum delay of the larger value of 100ms or pgood_delay
  	 * so that the power can stablize before the devices are queried
  	 */
  	hub->query_delay = get_timer(0) + max(100, (int)pgood_delay);
  
  	/*
  	 * Record the power-on timeout here. The max. delay (timeout)
  	 * will be done based on this value in the USB port loop in
  	 * usb_hub_configure() later.
  	 */
  	hub->connect_timeout = hub->query_delay + 1000;
  	debug("devnum=%d poweron: query_delay=%d connect_timeout=%d
  ",
  	      dev->devnum, max(100, (int)pgood_delay),
  	      max(100, (int)pgood_delay) + 1000);

  }

  #if !CONFIG_IS_ENABLED(DM_USB)

  static struct usb_hub_device hub_dev[USB_MAX_HUB];
  static int usb_hub_index;

  void usb_hub_reset(void)
  {
  	usb_hub_index = 0;

  
  	/* Zero out global hub_dev in case its re-used again */
  	memset(hub_dev, 0, sizeof(hub_dev));

  }
  
  static struct usb_hub_device *usb_hub_allocate(void)
  {
  	if (usb_hub_index < USB_MAX_HUB)
  		return &hub_dev[usb_hub_index++];
  
  	printf("ERROR: USB_MAX_HUB (%d) reached
  ", USB_MAX_HUB);
  	return NULL;
  }

  #endif

  
  #define MAX_TRIES 5

  static inline const char *portspeed(int portstatus)

  {

  	switch (portstatus & USB_PORT_STAT_SPEED_MASK) {
  	case USB_PORT_STAT_SUPER_SPEED:

  		return "5 Gb/s";

  	case USB_PORT_STAT_HIGH_SPEED:

  		return "480 Mb/s";

  	case USB_PORT_STAT_LOW_SPEED:

  		return "1.5 Mb/s";

  	default:

  		return "12 Mb/s";

  	}

  }

  /**
   * usb_hub_port_reset() - reset a port given its usb_device pointer
   *
   * Reset a hub port and see if a device is present on that port, providing
   * sufficient time for it to show itself. The port status is returned.
   *
   * @dev:	USB device to reset
   * @port:	Port number to reset (note ports are numbered from 0 here)
   * @portstat:	Returns port status
   */
  static int usb_hub_port_reset(struct usb_device *dev, int port,
  			      unsigned short *portstat)

  {

  	int err, tries;

  	ALLOC_CACHE_ALIGN_BUFFER(struct usb_port_status, portsts, 1);

  	unsigned short portstatus, portchange;

  	int delay = HUB_SHORT_RESET_TIME; /* start with short reset delay */

  #if CONFIG_IS_ENABLED(DM_USB)

  	debug("%s: resetting '%s' port %d...
  ", __func__, dev->dev->name,
  	      port + 1);
  #else
  	debug("%s: resetting port %d...
  ", __func__, port + 1);
  #endif

  	for (tries = 0; tries < MAX_TRIES; tries++) {

  		err = usb_set_port_feature(dev, port + 1, USB_PORT_FEAT_RESET);
  		if (err < 0)
  			return err;

  		mdelay(delay);

  		if (usb_get_port_status(dev, port + 1, portsts) < 0) {

  			debug("get_port_status failed status %lX
  ",
  			      dev->status);

  			return -1;
  		}

  		portstatus = le16_to_cpu(portsts->wPortStatus);
  		portchange = le16_to_cpu(portsts->wPortChange);

  		debug("portstatus %x, change %x, %s
  ", portstatus, portchange,
  							portspeed(portstatus));

  		debug("STAT_C_CONNECTION = %d STAT_CONNECTION = %d" \
  		      "  USB_PORT_STAT_ENABLE %d
  ",
  		      (portchange & USB_PORT_STAT_C_CONNECTION) ? 1 : 0,
  		      (portstatus & USB_PORT_STAT_CONNECTION) ? 1 : 0,
  		      (portstatus & USB_PORT_STAT_ENABLE) ? 1 : 0);

  		/*
  		 * Perhaps we should check for the following here:
  		 * - C_CONNECTION hasn't been set.
  		 * - CONNECTION is still set.
  		 *
  		 * Doing so would ensure that the device is still connected
  		 * to the bus, and hasn't been unplugged or replaced while the
  		 * USB bus reset was going on.
  		 *
  		 * However, if we do that, then (at least) a San Disk Ultra
  		 * USB 3.0 16GB device fails to reset on (at least) an NVIDIA
  		 * Tegra Jetson TK1 board. For some reason, the device appears
  		 * to briefly drop off the bus when this second bus reset is
  		 * executed, yet if we retry this loop, it'll eventually come
  		 * back after another reset or two.
  		 */

  
  		if (portstatus & USB_PORT_STAT_ENABLE)
  			break;

  		/* Switch to long reset delay for the next round */
  		delay = HUB_LONG_RESET_TIME;

  	}
  
  	if (tries == MAX_TRIES) {

  		debug("Cannot enable port %i after %i retries, " \
  		      "disabling port.
  ", port + 1, MAX_TRIES);
  		debug("Maybe the USB cable is bad?
  ");

  		return -1;
  	}
  
  	usb_clear_port_feature(dev, port + 1, USB_PORT_FEAT_C_RESET);
  	*portstat = portstatus;
  	return 0;
  }

  int usb_hub_port_connect_change(struct usb_device *dev, int port)

  {

  	ALLOC_CACHE_ALIGN_BUFFER(struct usb_port_status, portsts, 1);

  	unsigned short portstatus;

  	int ret, speed;

  
  	/* Check status */

  	ret = usb_get_port_status(dev, port + 1, portsts);
  	if (ret < 0) {

  		debug("get_port_status failed
  ");

  		return ret;

  	}

  	portstatus = le16_to_cpu(portsts->wPortStatus);

  	debug("portstatus %x, change %x, %s
  ",
  	      portstatus,
  	      le16_to_cpu(portsts->wPortChange),
  	      portspeed(portstatus));

  
  	/* Clear the connection change status */
  	usb_clear_port_feature(dev, port + 1, USB_PORT_FEAT_C_CONNECTION);
  
  	/* Disconnect any existing devices under this port */
  	if (((!(portstatus & USB_PORT_STAT_CONNECTION)) &&

  	     (!(portstatus & USB_PORT_STAT_ENABLE))) ||
  	    usb_device_has_child_on_port(dev, port)) {

  		debug("usb_disconnect(&hub->children[port]);
  ");

  		/* Return now if nothing is connected */
  		if (!(portstatus & USB_PORT_STAT_CONNECTION))

  			return -ENOTCONN;

  	}

  
  	/* Reset the port */

  	ret = usb_hub_port_reset(dev, port, &portstatus);

  	if (ret < 0) {

  		if (ret != -ENXIO)
  			printf("cannot reset port %i!?
  ", port + 1);

  		return ret;

  	}

  	switch (portstatus & USB_PORT_STAT_SPEED_MASK) {
  	case USB_PORT_STAT_SUPER_SPEED:

  		speed = USB_SPEED_SUPER;

  		break;
  	case USB_PORT_STAT_HIGH_SPEED:

  		speed = USB_SPEED_HIGH;

  		break;
  	case USB_PORT_STAT_LOW_SPEED:

  		speed = USB_SPEED_LOW;

  		break;
  	default:

  		speed = USB_SPEED_FULL;

  		break;
  	}

  #if CONFIG_IS_ENABLED(DM_USB)

  	struct udevice *child;
  
  	ret = usb_scan_device(dev->dev, port + 1, speed, &child);
  #else
  	struct usb_device *usb;

  	ret = usb_alloc_new_device(dev->controller, &usb);
  	if (ret) {
  		printf("cannot create new device: ret=%d", ret);
  		return ret;
  	}

  	dev->children[port] = usb;

  	usb->speed = speed;

  	usb->parent = dev;
  	usb->portnr = port + 1;
  	/* Run it through the hoops (find a driver, etc) */

  	ret = usb_new_device(usb);
  	if (ret < 0) {

  		/* Woops, disable the port */

  		usb_free_device(dev->controller);

  		dev->children[port] = NULL;

  	}
  #endif
  	if (ret < 0) {

  		debug("hub: disabling port %d
  ", port + 1);

  		usb_clear_port_feature(dev, port + 1, USB_PORT_FEAT_ENABLE);
  	}

  
  	return ret;

  }

  static int usb_scan_port(struct usb_device_scan *usb_scan)
  {
  	ALLOC_CACHE_ALIGN_BUFFER(struct usb_port_status, portsts, 1);
  	unsigned short portstatus;
  	unsigned short portchange;
  	struct usb_device *dev;
  	struct usb_hub_device *hub;
  	int ret = 0;
  	int i;
  
  	dev = usb_scan->dev;
  	hub = usb_scan->hub;
  	i = usb_scan->port;
  
  	/*
  	 * Don't talk to the device before the query delay is expired.
  	 * This is needed for voltages to stabalize.
  	 */
  	if (get_timer(0) < hub->query_delay)
  		return 0;
  
  	ret = usb_get_port_status(dev, i + 1, portsts);
  	if (ret < 0) {
  		debug("get_port_status failed
  ");
  		if (get_timer(0) >= hub->connect_timeout) {
  			debug("devnum=%d port=%d: timeout
  ",
  			      dev->devnum, i + 1);
  			/* Remove this device from scanning list */
  			list_del(&usb_scan->list);
  			free(usb_scan);
  			return 0;
  		}

  		return 0;

  	}
  
  	portstatus = le16_to_cpu(portsts->wPortStatus);
  	portchange = le16_to_cpu(portsts->wPortChange);
  	debug("Port %d Status %X Change %X
  ", i + 1, portstatus, portchange);

  	/*
  	 * No connection change happened, wait a bit more.
  	 *
  	 * For some situation, the hub reports no connection change but a
  	 * device is connected to the port (eg: CCS bit is set but CSC is not
  	 * in the PORTSC register of a root hub), ignore such case.
  	 */
  	if (!(portchange & USB_PORT_STAT_C_CONNECTION) &&
  	    !(portstatus & USB_PORT_STAT_CONNECTION)) {

  		if (get_timer(0) >= hub->connect_timeout) {
  			debug("devnum=%d port=%d: timeout
  ",
  			      dev->devnum, i + 1);
  			/* Remove this device from scanning list */
  			list_del(&usb_scan->list);
  			free(usb_scan);
  			return 0;
  		}
  		return 0;
  	}

  	if (portchange & USB_PORT_STAT_C_RESET) {
  		debug("port %d reset change
  ", i + 1);
  		usb_clear_port_feature(dev, i + 1, USB_PORT_FEAT_C_RESET);
  	}

  	if ((portchange & USB_SS_PORT_STAT_C_BH_RESET) &&
  	    usb_hub_is_superspeed(dev)) {
  		debug("port %d BH reset change
  ", i + 1);
  		usb_clear_port_feature(dev, i + 1, USB_SS_PORT_FEAT_C_BH_RESET);
  	}

  	/* A new USB device is ready at this point */
  	debug("devnum=%d port=%d: USB dev found
  ", dev->devnum, i + 1);
  
  	usb_hub_port_connect_change(dev, i);
  
  	if (portchange & USB_PORT_STAT_C_ENABLE) {
  		debug("port %d enable change, status %x
  ", i + 1, portstatus);
  		usb_clear_port_feature(dev, i + 1, USB_PORT_FEAT_C_ENABLE);
  		/*
  		 * The following hack causes a ghost device problem
  		 * to Faraday EHCI
  		 */
  #ifndef CONFIG_USB_EHCI_FARADAY
  		/*
  		 * EM interference sometimes causes bad shielded USB
  		 * devices to be shutdown by the hub, this hack enables
  		 * them again. Works at least with mouse driver
  		 */
  		if (!(portstatus & USB_PORT_STAT_ENABLE) &&
  		    (portstatus & USB_PORT_STAT_CONNECTION) &&
  		    usb_device_has_child_on_port(dev, i)) {
  			debug("already running port %i disabled by hub (EMI?), re-enabling...
  ",
  			      i + 1);
  			usb_hub_port_connect_change(dev, i);
  		}
  #endif
  	}
  
  	if (portstatus & USB_PORT_STAT_SUSPEND) {
  		debug("port %d suspend change
  ", i + 1);
  		usb_clear_port_feature(dev, i + 1, USB_PORT_FEAT_SUSPEND);
  	}
  
  	if (portchange & USB_PORT_STAT_C_OVERCURRENT) {
  		debug("port %d over-current change
  ", i + 1);
  		usb_clear_port_feature(dev, i + 1,
  				       USB_PORT_FEAT_C_OVER_CURRENT);
  		/* Only power-on this one port */
  		usb_set_port_feature(dev, i + 1, USB_PORT_FEAT_POWER);
  		hub->overcurrent_count[i]++;
  
  		/*
  		 * If the max-scan-count is not reached, return without removing
  		 * the device from scan-list. This will re-issue a new scan.
  		 */
  		if (hub->overcurrent_count[i] <=
  		    PORT_OVERCURRENT_MAX_SCAN_COUNT)
  			return 0;
  
  		/* Otherwise the device will get removed */

  		printf("Port %d over-current occurred %d times
  ", i + 1,

  		       hub->overcurrent_count[i]);
  	}

  	/*
  	 * We're done with this device, so let's remove this device from
  	 * scanning list
  	 */
  	list_del(&usb_scan->list);
  	free(usb_scan);
  
  	return 0;
  }
  
  static int usb_device_list_scan(void)
  {
  	struct usb_device_scan *usb_scan;
  	struct usb_device_scan *tmp;
  	static int running;
  	int ret = 0;
  
  	/* Only run this loop once for each controller */
  	if (running)
  		return 0;
  
  	running = 1;
  
  	while (1) {
  		/* We're done, once the list is empty again */
  		if (list_empty(&usb_scan_list))
  			goto out;
  
  		list_for_each_entry_safe(usb_scan, tmp, &usb_scan_list, list) {
  			int ret;
  
  			/* Scan this port */
  			ret = usb_scan_port(usb_scan);
  			if (ret)
  				goto out;
  		}
  	}
  
  out:
  	/*
  	 * This USB controller has finished scanning all its connected
  	 * USB devices. Set "running" back to 0, so that other USB controllers
  	 * will scan their devices too.
  	 */
  	running = 0;
  
  	return ret;
  }

  static struct usb_hub_device *usb_get_hub_device(struct usb_device *dev)
  {
  	struct usb_hub_device *hub;

  #if !CONFIG_IS_ENABLED(DM_USB)

  	/* "allocate" Hub device */
  	hub = usb_hub_allocate();
  #else
  	hub = dev_get_uclass_priv(dev->dev);
  #endif
  
  	return hub;
  }

  static int usb_hub_configure(struct usb_device *dev)
  {

  	int i, length;

  	ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, USB_BUFSIZ);
  	unsigned char *bitmap;

  	short hubCharacteristics;

  	struct usb_hub_descriptor *descriptor;
  	struct usb_hub_device *hub;

  	struct usb_hub_status *hubsts;

  	int ret;

  	hub = usb_get_hub_device(dev);

  	if (hub == NULL)

  		return -ENOMEM;

  	hub->pusb_dev = dev;

  	/* Get the the hub descriptor */

  	ret = usb_get_hub_descriptor(dev, buffer, 4);
  	if (ret < 0) {

  		debug("usb_hub_configure: failed to get hub " \
  		      "descriptor, giving up %lX
  ", dev->status);

  		return ret;

  	}
  	descriptor = (struct usb_hub_descriptor *)buffer;

  	length = min_t(int, descriptor->bLength,
  		       sizeof(struct usb_hub_descriptor));

  	ret = usb_get_hub_descriptor(dev, buffer, length);
  	if (ret < 0) {

  		debug("usb_hub_configure: failed to get hub " \
  		      "descriptor 2nd giving up %lX
  ", dev->status);

  		return ret;

  	}

  	memcpy((unsigned char *)&hub->desc, buffer, length);

  	/* adjust 16bit values */

  	put_unaligned(le16_to_cpu(get_unaligned(
  			&descriptor->wHubCharacteristics)),
  			&hub->desc.wHubCharacteristics);

  	/* set the bitmap */

  	bitmap = (unsigned char *)&hub->desc.u.hs.DeviceRemovable[0];

  	/* devices not removable by default */
  	memset(bitmap, 0xff, (USB_MAXCHILDREN+1+7)/8);

  	bitmap = (unsigned char *)&hub->desc.u.hs.PortPowerCtrlMask[0];

  	memset(bitmap, 0xff, (USB_MAXCHILDREN+1+7)/8); /* PowerMask = 1B */
  
  	for (i = 0; i < ((hub->desc.bNbrPorts + 1 + 7)/8); i++)

  		hub->desc.u.hs.DeviceRemovable[i] =
  			descriptor->u.hs.DeviceRemovable[i];

  
  	for (i = 0; i < ((hub->desc.bNbrPorts + 1 + 7)/8); i++)

  		hub->desc.u.hs.PortPowerCtrlMask[i] =
  			descriptor->u.hs.PortPowerCtrlMask[i];

  
  	dev->maxchild = descriptor->bNbrPorts;

  	debug("%d ports detected
  ", dev->maxchild);

  	hubCharacteristics = get_unaligned(&hub->desc.wHubCharacteristics);
  	switch (hubCharacteristics & HUB_CHAR_LPSM) {

  	case 0x00:

  		debug("ganged power switching
  ");

  		break;
  	case 0x01:

  		debug("individual port power switching
  ");

  		break;
  	case 0x02:
  	case 0x03:

  		debug("unknown reserved power switching mode
  ");

  		break;
  	}

  	if (hubCharacteristics & HUB_CHAR_COMPOUND)

  		debug("part of a compound device
  ");

  	else

  		debug("standalone hub
  ");

  	switch (hubCharacteristics & HUB_CHAR_OCPM) {

  	case 0x00:

  		debug("global over-current protection
  ");

  		break;
  	case 0x08:

  		debug("individual port over-current protection
  ");

  		break;
  	case 0x10:
  	case 0x18:

  		debug("no over-current protection
  ");

  		break;
  	}

  	switch (dev->descriptor.bDeviceProtocol) {
  	case USB_HUB_PR_FS:
  		break;
  	case USB_HUB_PR_HS_SINGLE_TT:
  		debug("Single TT
  ");
  		break;
  	case USB_HUB_PR_HS_MULTI_TT:
  		ret = usb_set_interface(dev, 0, 1);
  		if (ret == 0) {
  			debug("TT per port
  ");
  			hub->tt.multi = true;
  		} else {
  			debug("Using single TT (err %d)
  ", ret);
  		}
  		break;
  	case USB_HUB_PR_SS:
  		/* USB 3.0 hubs don't have a TT */
  		break;
  	default:
  		debug("Unrecognized hub protocol %d
  ",
  		      dev->descriptor.bDeviceProtocol);
  		break;
  	}
  
  	/* Note 8 FS bit times == (8 bits / 12000000 bps) ~= 666ns */
  	switch (hubCharacteristics & HUB_CHAR_TTTT) {
  	case HUB_TTTT_8_BITS:
  		if (dev->descriptor.bDeviceProtocol != 0) {
  			hub->tt.think_time = 666;
  			debug("TT requires at most %d FS bit times (%d ns)
  ",
  			      8, hub->tt.think_time);
  		}
  		break;
  	case HUB_TTTT_16_BITS:
  		hub->tt.think_time = 666 * 2;
  		debug("TT requires at most %d FS bit times (%d ns)
  ",
  		      16, hub->tt.think_time);
  		break;
  	case HUB_TTTT_24_BITS:
  		hub->tt.think_time = 666 * 3;
  		debug("TT requires at most %d FS bit times (%d ns)
  ",
  		      24, hub->tt.think_time);
  		break;
  	case HUB_TTTT_32_BITS:
  		hub->tt.think_time = 666 * 4;
  		debug("TT requires at most %d FS bit times (%d ns)
  ",
  		      32, hub->tt.think_time);
  		break;
  	}

  	debug("power on to power good time: %dms
  ",
  	      descriptor->bPwrOn2PwrGood * 2);
  	debug("hub controller current requirement: %dmA
  ",
  	      descriptor->bHubContrCurrent);

  
  	for (i = 0; i < dev->maxchild; i++)

  		debug("port %d is%s removable
  ", i + 1,

  		      hub->desc.u.hs.DeviceRemovable[(i + 1) / 8] & \

  		      (1 << ((i + 1) % 8)) ? " not" : "");

  
  	if (sizeof(struct usb_hub_status) > USB_BUFSIZ) {

  		debug("usb_hub_configure: failed to get Status - " \
  		      "too long: %d
  ", descriptor->bLength);

  		return -EFBIG;

  	}

  	ret = usb_get_hub_status(dev, buffer);
  	if (ret < 0) {

  		debug("usb_hub_configure: failed to get Status %lX
  ",
  		      dev->status);

  		return ret;

  	}

  	hubsts = (struct usb_hub_status *)buffer;

  
  	debug("get_hub_status returned status %X, change %X
  ",
  	      le16_to_cpu(hubsts->wHubStatus),
  	      le16_to_cpu(hubsts->wHubChange));
  	debug("local power source is %s
  ",
  	      (le16_to_cpu(hubsts->wHubStatus) & HUB_STATUS_LOCAL_POWER) ? \
  	      "lost (inactive)" : "good");
  	debug("%sover-current condition exists
  ",
  	      (le16_to_cpu(hubsts->wHubStatus) & HUB_STATUS_OVERCURRENT) ? \
  	      "" : "no ");

  #if CONFIG_IS_ENABLED(DM_USB)

  	/*

  	 * Update USB host controller's internal representation of this hub
  	 * after the hub descriptor is fetched.
  	 */
  	ret = usb_update_hub_device(dev);
  	if (ret < 0 && ret != -ENOSYS) {
  		debug("%s: failed to update hub device for HCD (%x)
  ",
  		      __func__, ret);
  		return ret;
  	}
  
  	/*

  	 * A maximum of seven tiers are allowed in a USB topology, and the
  	 * root hub occupies the first tier. The last tier ends with a normal
  	 * USB device. USB 3.0 hubs use a 20-bit field called 'route string'
  	 * to route packets to the designated downstream port. The hub uses a
  	 * hub depth value multiplied by four as an offset into the 'route
  	 * string' to locate the bits it uses to determine the downstream
  	 * port number.
  	 */
  	if (usb_hub_is_root_hub(dev->dev)) {
  		hub->hub_depth = -1;
  	} else {
  		struct udevice *hdev;
  		int depth = 0;
  
  		hdev = dev->dev->parent;
  		while (!usb_hub_is_root_hub(hdev)) {
  			depth++;
  			hdev = hdev->parent;
  		}
  
  		hub->hub_depth = depth;
  
  		if (usb_hub_is_superspeed(dev)) {
  			debug("set hub (%p) depth to %d
  ", dev, depth);
  			/*
  			 * This request sets the value that the hub uses to
  			 * determine the index into the 'route string index'
  			 * for this hub.
  			 */
  			ret = usb_set_hub_depth(dev, depth);
  			if (ret < 0) {
  				debug("%s: failed to set hub depth (%lX)
  ",
  				      __func__, dev->status);
  				return ret;
  			}
  		}
  	}
  #endif

  	usb_hub_power_on(hub);

  	/*
  	 * Reset any devices that may be in a bad state when applying
  	 * the power.  This is a __weak function.  Resetting of the devices
  	 * should occur in the board file of the device.
  	 */
  	for (i = 0; i < dev->maxchild; i++)

  		usb_hub_reset_devices(hub, i + 1);

  	/*
  	 * Only add the connected USB devices, including potential hubs,
  	 * to a scanning list. This list will get scanned and devices that
  	 * are detected (either via port connected or via port timeout)
  	 * will get removed from this list. Scanning of the devices on this
  	 * list will continue until all devices are removed.
  	 */

  	for (i = 0; i < dev->maxchild; i++) {

  		struct usb_device_scan *usb_scan;

  		usb_scan = calloc(1, sizeof(*usb_scan));
  		if (!usb_scan) {
  			printf("Can't allocate memory for USB device!
  ");
  			return -ENOMEM;

  		}

  		usb_scan->dev = dev;
  		usb_scan->hub = hub;
  		usb_scan->port = i;
  		list_add_tail(&usb_scan->list, &usb_scan_list);
  	}

  	/*
  	 * And now call the scanning code which loops over the generated list
  	 */
  	ret = usb_device_list_scan();

  	return ret;

  }

  static int usb_hub_check(struct usb_device *dev, int ifnum)

  {
  	struct usb_interface *iface;

  	struct usb_endpoint_descriptor *ep = NULL;

  
  	iface = &dev->config.if_desc[ifnum];
  	/* Is it a hub? */
  	if (iface->desc.bInterfaceClass != USB_CLASS_HUB)

  		goto err;

  	/* Some hubs have a subclass of 1, which AFAICT according to the */
  	/*  specs is not defined, but it works */
  	if ((iface->desc.bInterfaceSubClass != 0) &&
  	    (iface->desc.bInterfaceSubClass != 1))

  		goto err;

  	/* Multiple endpoints? What kind of mutant ninja-hub is this? */
  	if (iface->desc.bNumEndpoints != 1)

  		goto err;

  	ep = &iface->ep_desc[0];
  	/* Output endpoint? Curiousier and curiousier.. */
  	if (!(ep->bEndpointAddress & USB_DIR_IN))

  		goto err;

  	/* If it's not an interrupt endpoint, we'd better punt! */
  	if ((ep->bmAttributes & 3) != 3)

  		goto err;

  	/* We found a hub */

  	debug("USB hub found
  ");

  	return 0;
  
  err:
  	debug("USB hub not found: bInterfaceClass=%d, bInterfaceSubClass=%d, bNumEndpoints=%d
  ",
  	      iface->desc.bInterfaceClass, iface->desc.bInterfaceSubClass,
  	      iface->desc.bNumEndpoints);
  	if (ep) {
  		debug("   bEndpointAddress=%#x, bmAttributes=%d",
  		      ep->bEndpointAddress, ep->bmAttributes);
  	}
  
  	return -ENOENT;
  }
  
  int usb_hub_probe(struct usb_device *dev, int ifnum)
  {
  	int ret;
  
  	ret = usb_hub_check(dev, ifnum);
  	if (ret)
  		return 0;

  	ret = usb_hub_configure(dev);
  	return ret;
  }

  #if CONFIG_IS_ENABLED(DM_USB)

  int usb_hub_scan(struct udevice *hub)
  {

  	struct usb_device *udev = dev_get_parent_priv(hub);

  
  	return usb_hub_configure(udev);
  }

  static int usb_hub_post_probe(struct udevice *dev)
  {
  	debug("%s
  ", __func__);
  	return usb_hub_scan(dev);
  }
  
  static const struct udevice_id usb_hub_ids[] = {
  	{ .compatible = "usb-hub" },
  	{ }
  };
  
  U_BOOT_DRIVER(usb_generic_hub) = {
  	.name	= "usb_hub",
  	.id	= UCLASS_USB_HUB,
  	.of_match = usb_hub_ids,
  	.flags	= DM_FLAG_ALLOC_PRIV_DMA,
  };
  
  UCLASS_DRIVER(usb_hub) = {
  	.id		= UCLASS_USB_HUB,
  	.name		= "usb_hub",

  	.post_bind	= dm_scan_fdt_dev,

  	.post_probe	= usb_hub_post_probe,
  	.child_pre_probe	= usb_child_pre_probe,
  	.per_child_auto_alloc_size = sizeof(struct usb_device),
  	.per_child_platdata_auto_alloc_size = sizeof(struct usb_dev_platdata),

  	.per_device_auto_alloc_size = sizeof(struct usb_hub_device),

  };
  
  static const struct usb_device_id hub_id_table[] = {
  	{
  		.match_flags = USB_DEVICE_ID_MATCH_DEV_CLASS,
  		.bDeviceClass = USB_CLASS_HUB
  	},
  	{ }	/* Terminating entry */
  };

  U_BOOT_USB_DEVICE(usb_generic_hub, hub_id_table);

  
  #endif