text: // SPDX-License-Identifier: GPL-2.0
  /*
   * Thunderbolt driver - switch/port utility functions
   *
   * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
   * Copyright (C) 2018, Intel Corporation
   */
  
  #include <linux/delay.h>
  #include <linux/idr.h>
  #include <linux/nvmem-provider.h>
  #include <linux/pm_runtime.h>
  #include <linux/sched/signal.h>
  #include <linux/sizes.h>
  #include <linux/slab.h>
  
  #include "tb.h"
  
  /* Switch NVM support */
  
  #define NVM_CSS			0x10
  
  struct nvm_auth_status {
  	struct list_head list;
  	uuid_t uuid;
  	u32 status;
  };
  
  enum nvm_write_ops {
  	WRITE_AND_AUTHENTICATE = 1,
  	WRITE_ONLY = 2,
  };
  
  /*
   * Hold NVM authentication failure status per switch This information
   * needs to stay around even when the switch gets power cycled so we
   * keep it separately.
   */
  static LIST_HEAD(nvm_auth_status_cache);
  static DEFINE_MUTEX(nvm_auth_status_lock);
  
  static struct nvm_auth_status *__nvm_get_auth_status(const struct tb_switch *sw)
  {
  	struct nvm_auth_status *st;
  
  	list_for_each_entry(st, &nvm_auth_status_cache, list) {
  		if (uuid_equal(&st->uuid, sw->uuid))
  			return st;
  	}
  
  	return NULL;
  }
  
  static void nvm_get_auth_status(const struct tb_switch *sw, u32 *status)
  {
  	struct nvm_auth_status *st;
  
  	mutex_lock(&nvm_auth_status_lock);
  	st = __nvm_get_auth_status(sw);
  	mutex_unlock(&nvm_auth_status_lock);
  
  	*status = st ? st->status : 0;
  }
  
  static void nvm_set_auth_status(const struct tb_switch *sw, u32 status)
  {
  	struct nvm_auth_status *st;
  
  	if (WARN_ON(!sw->uuid))
  		return;
  
  	mutex_lock(&nvm_auth_status_lock);
  	st = __nvm_get_auth_status(sw);
  
  	if (!st) {
  		st = kzalloc(sizeof(*st), GFP_KERNEL);
  		if (!st)
  			goto unlock;
  
  		memcpy(&st->uuid, sw->uuid, sizeof(st->uuid));
  		INIT_LIST_HEAD(&st->list);
  		list_add_tail(&st->list, &nvm_auth_status_cache);
  	}
  
  	st->status = status;
  unlock:
  	mutex_unlock(&nvm_auth_status_lock);
  }
  
  static void nvm_clear_auth_status(const struct tb_switch *sw)
  {
  	struct nvm_auth_status *st;
  
  	mutex_lock(&nvm_auth_status_lock);
  	st = __nvm_get_auth_status(sw);
  	if (st) {
  		list_del(&st->list);
  		kfree(st);
  	}
  	mutex_unlock(&nvm_auth_status_lock);
  }
  
  static int nvm_validate_and_write(struct tb_switch *sw)
  {
  	unsigned int image_size, hdr_size;
  	const u8 *buf = sw->nvm->buf;
  	u16 ds_size;
  	int ret;
  
  	if (!buf)
  		return -EINVAL;
  
  	image_size = sw->nvm->buf_data_size;
  	if (image_size < NVM_MIN_SIZE || image_size > NVM_MAX_SIZE)
  		return -EINVAL;
  
  	/*
  	 * FARB pointer must point inside the image and must at least
  	 * contain parts of the digital section we will be reading here.
  	 */
  	hdr_size = (*(u32 *)buf) & 0xffffff;
  	if (hdr_size + NVM_DEVID + 2 >= image_size)
  		return -EINVAL;
  
  	/* Digital section start should be aligned to 4k page */
  	if (!IS_ALIGNED(hdr_size, SZ_4K))
  		return -EINVAL;
  
  	/*
  	 * Read digital section size and check that it also fits inside
  	 * the image.
  	 */
  	ds_size = *(u16 *)(buf + hdr_size);
  	if (ds_size >= image_size)
  		return -EINVAL;
  
  	if (!sw->safe_mode) {
  		u16 device_id;
  
  		/*
  		 * Make sure the device ID in the image matches the one
  		 * we read from the switch config space.
  		 */
  		device_id = *(u16 *)(buf + hdr_size + NVM_DEVID);
  		if (device_id != sw->config.device_id)
  			return -EINVAL;
  
  		if (sw->generation < 3) {
  			/* Write CSS headers first */
  			ret = dma_port_flash_write(sw->dma_port,
  				DMA_PORT_CSS_ADDRESS, buf + NVM_CSS,
  				DMA_PORT_CSS_MAX_SIZE);
  			if (ret)
  				return ret;
  		}
  
  		/* Skip headers in the image */
  		buf += hdr_size;
  		image_size -= hdr_size;
  	}
  
  	if (tb_switch_is_usb4(sw))
  		ret = usb4_switch_nvm_write(sw, 0, buf, image_size);
  	else
  		ret = dma_port_flash_write(sw->dma_port, 0, buf, image_size);
  	if (!ret)
  		sw->nvm->flushed = true;
  	return ret;
  }
  
  static int nvm_authenticate_host_dma_port(struct tb_switch *sw)
  {
  	int ret = 0;
  
  	/*
  	 * Root switch NVM upgrade requires that we disconnect the
  	 * existing paths first (in case it is not in safe mode
  	 * already).
  	 */
  	if (!sw->safe_mode) {
  		u32 status;
  
  		ret = tb_domain_disconnect_all_paths(sw->tb);
  		if (ret)
  			return ret;
  		/*
  		 * The host controller goes away pretty soon after this if
  		 * everything goes well so getting timeout is expected.
  		 */
  		ret = dma_port_flash_update_auth(sw->dma_port);
  		if (!ret || ret == -ETIMEDOUT)
  			return 0;
  
  		/*
  		 * Any error from update auth operation requires power
  		 * cycling of the host router.
  		 */
  		tb_sw_warn(sw, "failed to authenticate NVM, power cycling\n");
  		if (dma_port_flash_update_auth_status(sw->dma_port, &status) > 0)
  			nvm_set_auth_status(sw, status);
  	}
  
  	/*
  	 * From safe mode we can get out by just power cycling the
  	 * switch.
  	 */
  	dma_port_power_cycle(sw->dma_port);
  	return ret;
  }
  
  static int nvm_authenticate_device_dma_port(struct tb_switch *sw)
  {
  	int ret, retries = 10;
  
  	ret = dma_port_flash_update_auth(sw->dma_port);
  	switch (ret) {
  	case 0:
  	case -ETIMEDOUT:
  	case -EACCES:
  	case -EINVAL:
  		/* Power cycle is required */
  		break;
  	default:
  		return ret;
  	}
  
  	/*
  	 * Poll here for the authentication status. It takes some time
  	 * for the device to respond (we get timeout for a while). Once
  	 * we get response the device needs to be power cycled in order
  	 * to the new NVM to be taken into use.
  	 */
  	do {
  		u32 status;
  
  		ret = dma_port_flash_update_auth_status(sw->dma_port, &status);
  		if (ret < 0 && ret != -ETIMEDOUT)
  			return ret;
  		if (ret > 0) {
  			if (status) {
  				tb_sw_warn(sw, "failed to authenticate NVM\n");
  				nvm_set_auth_status(sw, status);
  			}
  
  			tb_sw_info(sw, "power cycling the switch now\n");
  			dma_port_power_cycle(sw->dma_port);
  			return 0;
  		}
  
  		msleep(500);
  	} while (--retries);
  
  	return -ETIMEDOUT;
  }
  
  static void nvm_authenticate_start_dma_port(struct tb_switch *sw)
  {
  	struct pci_dev *root_port;
  
  	/*
  	 * During host router NVM upgrade we should not allow root port to
  	 * go into D3cold because some root ports cannot trigger PME
  	 * itself. To be on the safe side keep the root port in D0 during
  	 * the whole upgrade process.
  	 */
  	root_port = pcie_find_root_port(sw->tb->nhi->pdev);
  	if (root_port)
  		pm_runtime_get_noresume(&root_port->dev);
  }
  
  static void nvm_authenticate_complete_dma_port(struct tb_switch *sw)
  {
  	struct pci_dev *root_port;
  
  	root_port = pcie_find_root_port(sw->tb->nhi->pdev);
  	if (root_port)
  		pm_runtime_put(&root_port->dev);
  }
  
  static inline bool nvm_readable(struct tb_switch *sw)
  {
  	if (tb_switch_is_usb4(sw)) {
  		/*
  		 * USB4 devices must support NVM operations but it is
  		 * optional for hosts. Therefore we query the NVM sector
  		 * size here and if it is supported assume NVM
  		 * operations are implemented.
  		 */
  		return usb4_switch_nvm_sector_size(sw) > 0;
  	}
  
  	/* Thunderbolt 2 and 3 devices support NVM through DMA port */
  	return !!sw->dma_port;
  }
  
  static inline bool nvm_upgradeable(struct tb_switch *sw)
  {
  	if (sw->no_nvm_upgrade)
  		return false;
  	return nvm_readable(sw);
  }
  
  static inline int nvm_read(struct tb_switch *sw, unsigned int address,
  			   void *buf, size_t size)
  {
  	if (tb_switch_is_usb4(sw))
  		return usb4_switch_nvm_read(sw, address, buf, size);
  	return dma_port_flash_read(sw->dma_port, address, buf, size);
  }
  
  static int nvm_authenticate(struct tb_switch *sw)
  {
  	int ret;
  
  	if (tb_switch_is_usb4(sw))
  		return usb4_switch_nvm_authenticate(sw);
  
  	if (!tb_route(sw)) {
  		nvm_authenticate_start_dma_port(sw);
  		ret = nvm_authenticate_host_dma_port(sw);
  	} else {
  		ret = nvm_authenticate_device_dma_port(sw);
  	}
  
  	return ret;
  }
  
  static int tb_switch_nvm_read(void *priv, unsigned int offset, void *val,
  			      size_t bytes)
  {
  	struct tb_nvm *nvm = priv;
  	struct tb_switch *sw = tb_to_switch(nvm->dev);
  	int ret;
  
  	pm_runtime_get_sync(&sw->dev);
  
  	if (!mutex_trylock(&sw->tb->lock)) {
  		ret = restart_syscall();
  		goto out;
  	}
  
  	ret = nvm_read(sw, offset, val, bytes);
  	mutex_unlock(&sw->tb->lock);
  
  out:
  	pm_runtime_mark_last_busy(&sw->dev);
  	pm_runtime_put_autosuspend(&sw->dev);
  
  	return ret;
  }
  
  static int tb_switch_nvm_write(void *priv, unsigned int offset, void *val,
  			       size_t bytes)
  {
  	struct tb_nvm *nvm = priv;
  	struct tb_switch *sw = tb_to_switch(nvm->dev);
  	int ret;
  
  	if (!mutex_trylock(&sw->tb->lock))
  		return restart_syscall();
  
  	/*
  	 * Since writing the NVM image might require some special steps,
  	 * for example when CSS headers are written, we cache the image
  	 * locally here and handle the special cases when the user asks
  	 * us to authenticate the image.
  	 */
  	ret = tb_nvm_write_buf(nvm, offset, val, bytes);
  	mutex_unlock(&sw->tb->lock);
  
  	return ret;
  }
  
  static int tb_switch_nvm_add(struct tb_switch *sw)
  {
  	struct tb_nvm *nvm;
  	u32 val;
  	int ret;
  
  	if (!nvm_readable(sw))
  		return 0;
  
  	/*
  	 * The NVM format of non-Intel hardware is not known so
  	 * currently restrict NVM upgrade for Intel hardware. We may
  	 * relax this in the future when we learn other NVM formats.
  	 */
  	if (sw->config.vendor_id != PCI_VENDOR_ID_INTEL &&
  	    sw->config.vendor_id != 0x8087) {
  		dev_info(&sw->dev,
  			 "NVM format of vendor %#x is not known, disabling NVM upgrade\n",
  			 sw->config.vendor_id);
  		return 0;
  	}
  
  	nvm = tb_nvm_alloc(&sw->dev);
  	if (IS_ERR(nvm))
  		return PTR_ERR(nvm);
  
  	/*
  	 * If the switch is in safe-mode the only accessible portion of
  	 * the NVM is the non-active one where userspace is expected to
  	 * write new functional NVM.
  	 */
  	if (!sw->safe_mode) {
  		u32 nvm_size, hdr_size;
  
  		ret = nvm_read(sw, NVM_FLASH_SIZE, &val, sizeof(val));
  		if (ret)
  			goto err_nvm;
  
  		hdr_size = sw->generation < 3 ? SZ_8K : SZ_16K;
  		nvm_size = (SZ_1M << (val & 7)) / 8;
  		nvm_size = (nvm_size - hdr_size) / 2;
  
  		ret = nvm_read(sw, NVM_VERSION, &val, sizeof(val));
  		if (ret)
  			goto err_nvm;
  
  		nvm->major = val >> 16;
  		nvm->minor = val >> 8;
  
  		ret = tb_nvm_add_active(nvm, nvm_size, tb_switch_nvm_read);
  		if (ret)
  			goto err_nvm;
  	}
  
  	if (!sw->no_nvm_upgrade) {
  		ret = tb_nvm_add_non_active(nvm, NVM_MAX_SIZE,
  					    tb_switch_nvm_write);
  		if (ret)
  			goto err_nvm;
  	}
  
  	sw->nvm = nvm;
  	return 0;
  
  err_nvm:
  	tb_nvm_free(nvm);
  	return ret;
  }
  
  static void tb_switch_nvm_remove(struct tb_switch *sw)
  {
  	struct tb_nvm *nvm;
  
  	nvm = sw->nvm;
  	sw->nvm = NULL;
  
  	if (!nvm)
  		return;
  
  	/* Remove authentication status in case the switch is unplugged */
  	if (!nvm->authenticating)
  		nvm_clear_auth_status(sw);
  
  	tb_nvm_free(nvm);
  }
  
  /* port utility functions */
  
  static const char *tb_port_type(struct tb_regs_port_header *port)
  {
  	switch (port->type >> 16) {
  	case 0:
  		switch ((u8) port->type) {
  		case 0:
  			return "Inactive";
  		case 1:
  			return "Port";
  		case 2:
  			return "NHI";
  		default:
  			return "unknown";
  		}
  	case 0x2:
  		return "Ethernet";
  	case 0x8:
  		return "SATA";
  	case 0xe:
  		return "DP/HDMI";
  	case 0x10:
  		return "PCIe";
  	case 0x20:
  		return "USB";
  	default:
  		return "unknown";
  	}
  }
  
  static void tb_dump_port(struct tb *tb, struct tb_regs_port_header *port)
  {
  	tb_dbg(tb,
  	       " Port %d: %x:%x (Revision: %d, TB Version: %d, Type: %s (%#x))\n",
  	       port->port_number, port->vendor_id, port->device_id,
  	       port->revision, port->thunderbolt_version, tb_port_type(port),
  	       port->type);
  	tb_dbg(tb, "  Max hop id (in/out): %d/%d\n",
  	       port->max_in_hop_id, port->max_out_hop_id);
  	tb_dbg(tb, "  Max counters: %d\n", port->max_counters);
  	tb_dbg(tb, "  NFC Credits: %#x\n", port->nfc_credits);
  }
  
  /**
   * tb_port_state() - get connectedness state of a port
   * @port: the port to check
   *
   * The port must have a TB_CAP_PHY (i.e. it should be a real port).
   *
   * Return: Returns an enum tb_port_state on success or an error code on failure.
   */
  int tb_port_state(struct tb_port *port)
  {
  	struct tb_cap_phy phy;
  	int res;
  	if (port->cap_phy == 0) {
  		tb_port_WARN(port, "does not have a PHY\n");
  		return -EINVAL;
  	}
  	res = tb_port_read(port, &phy, TB_CFG_PORT, port->cap_phy, 2);
  	if (res)
  		return res;
  	return phy.state;
  }
  
  /**
   * tb_wait_for_port() - wait for a port to become ready
   * @port: Port to wait
   * @wait_if_unplugged: Wait also when port is unplugged
   *
   * Wait up to 1 second for a port to reach state TB_PORT_UP. If
   * wait_if_unplugged is set then we also wait if the port is in state
   * TB_PORT_UNPLUGGED (it takes a while for the device to be registered after
   * switch resume). Otherwise we only wait if a device is registered but the link
   * has not yet been established.
   *
   * Return: Returns an error code on failure. Returns 0 if the port is not
   * connected or failed to reach state TB_PORT_UP within one second. Returns 1
   * if the port is connected and in state TB_PORT_UP.
   */
  int tb_wait_for_port(struct tb_port *port, bool wait_if_unplugged)
  {
  	int retries = 10;
  	int state;
  	if (!port->cap_phy) {
  		tb_port_WARN(port, "does not have PHY\n");
  		return -EINVAL;
  	}
  	if (tb_is_upstream_port(port)) {
  		tb_port_WARN(port, "is the upstream port\n");
  		return -EINVAL;
  	}
  
  	while (retries--) {
  		state = tb_port_state(port);
  		if (state < 0)
  			return state;
  		if (state == TB_PORT_DISABLED) {
  			tb_port_dbg(port, "is disabled (state: 0)\n");
  			return 0;
  		}
  		if (state == TB_PORT_UNPLUGGED) {
  			if (wait_if_unplugged) {
  				/* used during resume */
  				tb_port_dbg(port,
  					    "is unplugged (state: 7), retrying...\n");
  				msleep(100);
  				continue;
  			}
  			tb_port_dbg(port, "is unplugged (state: 7)\n");
  			return 0;
  		}
  		if (state == TB_PORT_UP) {
  			tb_port_dbg(port, "is connected, link is up (state: 2)\n");
  			return 1;
  		}
  
  		/*
  		 * After plug-in the state is TB_PORT_CONNECTING. Give it some
  		 * time.
  		 */
  		tb_port_dbg(port,
  			    "is connected, link is not up (state: %d), retrying...\n",
  			    state);
  		msleep(100);
  	}
  	tb_port_warn(port,
  		     "failed to reach state TB_PORT_UP. Ignoring port...\n");
  	return 0;
  }
  
  /**
   * tb_port_add_nfc_credits() - add/remove non flow controlled credits to port
   * @port: Port to add/remove NFC credits
   * @credits: Credits to add/remove
   *
   * Change the number of NFC credits allocated to @port by @credits. To remove
   * NFC credits pass a negative amount of credits.
   *
   * Return: Returns 0 on success or an error code on failure.
   */
  int tb_port_add_nfc_credits(struct tb_port *port, int credits)
  {
  	u32 nfc_credits;
  
  	if (credits == 0 || port->sw->is_unplugged)
  		return 0;
  
  	/*
  	 * USB4 restricts programming NFC buffers to lane adapters only
  	 * so skip other ports.
  	 */
  	if (tb_switch_is_usb4(port->sw) && !tb_port_is_null(port))
  		return 0;
  
  	nfc_credits = port->config.nfc_credits & ADP_CS_4_NFC_BUFFERS_MASK;
  	nfc_credits += credits;
  
  	tb_port_dbg(port, "adding %d NFC credits to %lu", credits,
  		    port->config.nfc_credits & ADP_CS_4_NFC_BUFFERS_MASK);
  
  	port->config.nfc_credits &= ~ADP_CS_4_NFC_BUFFERS_MASK;
  	port->config.nfc_credits |= nfc_credits;
  
  	return tb_port_write(port, &port->config.nfc_credits,
  			     TB_CFG_PORT, ADP_CS_4, 1);
  }
  
  /**
   * tb_port_clear_counter() - clear a counter in TB_CFG_COUNTER
   * @port: Port whose counters to clear
   * @counter: Counter index to clear
   *
   * Return: Returns 0 on success or an error code on failure.
   */
  int tb_port_clear_counter(struct tb_port *port, int counter)
  {
  	u32 zero[3] = { 0, 0, 0 };
  	tb_port_dbg(port, "clearing counter %d\n", counter);
  	return tb_port_write(port, zero, TB_CFG_COUNTERS, 3 * counter, 3);
  }
  
  /**
   * tb_port_unlock() - Unlock downstream port
   * @port: Port to unlock
   *
   * Needed for USB4 but can be called for any CIO/USB4 ports. Makes the
   * downstream router accessible for CM.
   */
  int tb_port_unlock(struct tb_port *port)
  {
  	if (tb_switch_is_icm(port->sw))
  		return 0;
  	if (!tb_port_is_null(port))
  		return -EINVAL;
  	if (tb_switch_is_usb4(port->sw))
  		return usb4_port_unlock(port);
  	return 0;
  }
  
  static int __tb_port_enable(struct tb_port *port, bool enable)
  {
  	int ret;
  	u32 phy;
  
  	if (!tb_port_is_null(port))
  		return -EINVAL;
  
  	ret = tb_port_read(port, &phy, TB_CFG_PORT,
  			   port->cap_phy + LANE_ADP_CS_1, 1);
  	if (ret)
  		return ret;
  
  	if (enable)
  		phy &= ~LANE_ADP_CS_1_LD;
  	else
  		phy |= LANE_ADP_CS_1_LD;
  
  	return tb_port_write(port, &phy, TB_CFG_PORT,
  			     port->cap_phy + LANE_ADP_CS_1, 1);
  }
  
  /**
   * tb_port_enable() - Enable lane adapter
   * @port: Port to enable (can be %NULL)
   *
   * This is used for lane 0 and 1 adapters to enable it.
   */
  int tb_port_enable(struct tb_port *port)
  {
  	return __tb_port_enable(port, true);
  }
  
  /**
   * tb_port_disable() - Disable lane adapter
   * @port: Port to disable (can be %NULL)
   *
   * This is used for lane 0 and 1 adapters to disable it.
   */
  int tb_port_disable(struct tb_port *port)
  {
  	return __tb_port_enable(port, false);
  }
  
  /*
   * tb_init_port() - initialize a port
   *
   * This is a helper method for tb_switch_alloc. Does not check or initialize
   * any downstream switches.
   *
   * Return: Returns 0 on success or an error code on failure.
   */
  static int tb_init_port(struct tb_port *port)
  {
  	int res;
  	int cap;
  
  	res = tb_port_read(port, &port->config, TB_CFG_PORT, 0, 8);
  	if (res) {
  		if (res == -ENODEV) {
  			tb_dbg(port->sw->tb, " Port %d: not implemented\n",
  			       port->port);
  			port->disabled = true;
  			return 0;
  		}
  		return res;
  	}
  
  	/* Port 0 is the switch itself and has no PHY. */
  	if (port->config.type == TB_TYPE_PORT && port->port != 0) {
  		cap = tb_port_find_cap(port, TB_PORT_CAP_PHY);
  
  		if (cap > 0)
  			port->cap_phy = cap;
  		else
  			tb_port_WARN(port, "non switch port without a PHY\n");
  
  		cap = tb_port_find_cap(port, TB_PORT_CAP_USB4);
  		if (cap > 0)
  			port->cap_usb4 = cap;
  	} else if (port->port != 0) {
  		cap = tb_port_find_cap(port, TB_PORT_CAP_ADAP);
  		if (cap > 0)
  			port->cap_adap = cap;
  	}
  
  	tb_dump_port(port->sw->tb, &port->config);
  
  	INIT_LIST_HEAD(&port->list);
  	return 0;
  
  }
  
  static int tb_port_alloc_hopid(struct tb_port *port, bool in, int min_hopid,
  			       int max_hopid)
  {
  	int port_max_hopid;
  	struct ida *ida;
  
  	if (in) {
  		port_max_hopid = port->config.max_in_hop_id;
  		ida = &port->in_hopids;
  	} else {
  		port_max_hopid = port->config.max_out_hop_id;
  		ida = &port->out_hopids;
  	}
  
  	/*
  	 * NHI can use HopIDs 1-max for other adapters HopIDs 0-7 are
  	 * reserved.
  	 */
  	if (!tb_port_is_nhi(port) && min_hopid < TB_PATH_MIN_HOPID)
  		min_hopid = TB_PATH_MIN_HOPID;
  
  	if (max_hopid < 0 || max_hopid > port_max_hopid)
  		max_hopid = port_max_hopid;
  
  	return ida_simple_get(ida, min_hopid, max_hopid + 1, GFP_KERNEL);
  }
  
  /**
   * tb_port_alloc_in_hopid() - Allocate input HopID from port
   * @port: Port to allocate HopID for
   * @min_hopid: Minimum acceptable input HopID
   * @max_hopid: Maximum acceptable input HopID
   *
   * Return: HopID between @min_hopid and @max_hopid or negative errno in
   * case of error.
   */
  int tb_port_alloc_in_hopid(struct tb_port *port, int min_hopid, int max_hopid)
  {
  	return tb_port_alloc_hopid(port, true, min_hopid, max_hopid);
  }
  
  /**
   * tb_port_alloc_out_hopid() - Allocate output HopID from port
   * @port: Port to allocate HopID for
   * @min_hopid: Minimum acceptable output HopID
   * @max_hopid: Maximum acceptable output HopID
   *
   * Return: HopID between @min_hopid and @max_hopid or negative errno in
   * case of error.
   */
  int tb_port_alloc_out_hopid(struct tb_port *port, int min_hopid, int max_hopid)
  {
  	return tb_port_alloc_hopid(port, false, min_hopid, max_hopid);
  }
  
  /**
   * tb_port_release_in_hopid() - Release allocated input HopID from port
   * @port: Port whose HopID to release
   * @hopid: HopID to release
   */
  void tb_port_release_in_hopid(struct tb_port *port, int hopid)
  {
  	ida_simple_remove(&port->in_hopids, hopid);
  }
  
  /**
   * tb_port_release_out_hopid() - Release allocated output HopID from port
   * @port: Port whose HopID to release
   * @hopid: HopID to release
   */
  void tb_port_release_out_hopid(struct tb_port *port, int hopid)
  {
  	ida_simple_remove(&port->out_hopids, hopid);
  }
  
  static inline bool tb_switch_is_reachable(const struct tb_switch *parent,
  					  const struct tb_switch *sw)
  {
  	u64 mask = (1ULL << parent->config.depth * 8) - 1;
  	return (tb_route(parent) & mask) == (tb_route(sw) & mask);
  }
  
  /**
   * tb_next_port_on_path() - Return next port for given port on a path
   * @start: Start port of the walk
   * @end: End port of the walk
   * @prev: Previous port (%NULL if this is the first)
   *
   * This function can be used to walk from one port to another if they
   * are connected through zero or more switches. If the @prev is dual
   * link port, the function follows that link and returns another end on
   * that same link.
   *
   * If the @end port has been reached, return %NULL.
   *
   * Domain tb->lock must be held when this function is called.
   */
  struct tb_port *tb_next_port_on_path(struct tb_port *start, struct tb_port *end,
  				     struct tb_port *prev)
  {
  	struct tb_port *next;
  
  	if (!prev)
  		return start;
  
  	if (prev->sw == end->sw) {
  		if (prev == end)
  			return NULL;
  		return end;
  	}
  
  	if (tb_switch_is_reachable(prev->sw, end->sw)) {
  		next = tb_port_at(tb_route(end->sw), prev->sw);
  		/* Walk down the topology if next == prev */
  		if (prev->remote &&
  		    (next == prev || next->dual_link_port == prev))
  			next = prev->remote;
  	} else {
  		if (tb_is_upstream_port(prev)) {
  			next = prev->remote;
  		} else {
  			next = tb_upstream_port(prev->sw);
  			/*
  			 * Keep the same link if prev and next are both
  			 * dual link ports.
  			 */
  			if (next->dual_link_port &&
  			    next->link_nr != prev->link_nr) {
  				next = next->dual_link_port;
  			}
  		}
  	}
  
  	return next != prev ? next : NULL;
  }
  
  /**
   * tb_port_get_link_speed() - Get current link speed
   * @port: Port to check (USB4 or CIO)
   *
   * Returns link speed in Gb/s or negative errno in case of failure.
   */
  int tb_port_get_link_speed(struct tb_port *port)
  {
  	u32 val, speed;
  	int ret;
  
  	if (!port->cap_phy)
  		return -EINVAL;
  
  	ret = tb_port_read(port, &val, TB_CFG_PORT,
  			   port->cap_phy + LANE_ADP_CS_1, 1);
  	if (ret)
  		return ret;
  
  	speed = (val & LANE_ADP_CS_1_CURRENT_SPEED_MASK) >>
  		LANE_ADP_CS_1_CURRENT_SPEED_SHIFT;
  	return speed == LANE_ADP_CS_1_CURRENT_SPEED_GEN3 ? 20 : 10;
  }
  
  /**
   * tb_port_get_link_width() - Get current link width
   * @port: Port to check (USB4 or CIO)
   *
   * Returns link width. Return values can be 1 (Single-Lane), 2 (Dual-Lane)
   * or negative errno in case of failure.
   */
  int tb_port_get_link_width(struct tb_port *port)
  {
  	u32 val;
  	int ret;
  
  	if (!port->cap_phy)
  		return -EINVAL;
  
  	ret = tb_port_read(port, &val, TB_CFG_PORT,
  			   port->cap_phy + LANE_ADP_CS_1, 1);
  	if (ret)
  		return ret;
  
  	return (val & LANE_ADP_CS_1_CURRENT_WIDTH_MASK) >>
  		LANE_ADP_CS_1_CURRENT_WIDTH_SHIFT;
  }
  
  static bool tb_port_is_width_supported(struct tb_port *port, int width)
  {
  	u32 phy, widths;
  	int ret;
  
  	if (!port->cap_phy)
  		return false;
  
  	ret = tb_port_read(port, &phy, TB_CFG_PORT,
  			   port->cap_phy + LANE_ADP_CS_0, 1);
  	if (ret)
  		return false;
  
  	widths = (phy & LANE_ADP_CS_0_SUPPORTED_WIDTH_MASK) >>
  		LANE_ADP_CS_0_SUPPORTED_WIDTH_SHIFT;
  
  	return !!(widths & width);
  }
  
  static int tb_port_set_link_width(struct tb_port *port, unsigned int width)
  {
  	u32 val;
  	int ret;
  
  	if (!port->cap_phy)
  		return -EINVAL;
  
  	ret = tb_port_read(port, &val, TB_CFG_PORT,
  			   port->cap_phy + LANE_ADP_CS_1, 1);
  	if (ret)
  		return ret;
  
  	val &= ~LANE_ADP_CS_1_TARGET_WIDTH_MASK;
  	switch (width) {
  	case 1:
  		val |= LANE_ADP_CS_1_TARGET_WIDTH_SINGLE <<
  			LANE_ADP_CS_1_TARGET_WIDTH_SHIFT;
  		break;
  	case 2:
  		val |= LANE_ADP_CS_1_TARGET_WIDTH_DUAL <<
  			LANE_ADP_CS_1_TARGET_WIDTH_SHIFT;
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	val |= LANE_ADP_CS_1_LB;
  
  	return tb_port_write(port, &val, TB_CFG_PORT,
  			     port->cap_phy + LANE_ADP_CS_1, 1);
  }
  
  /**
   * tb_port_lane_bonding_enable() - Enable bonding on port
   * @port: port to enable
   *
   * Enable bonding by setting the link width of the port and the
   * other port in case of dual link port.
   *
   * Return: %0 in case of success and negative errno in case of error
   */
  int tb_port_lane_bonding_enable(struct tb_port *port)
  {
  	int ret;
  
  	/*
  	 * Enable lane bonding for both links if not already enabled by
  	 * for example the boot firmware.
  	 */
  	ret = tb_port_get_link_width(port);
  	if (ret == 1) {
  		ret = tb_port_set_link_width(port, 2);
  		if (ret)
  			return ret;
  	}
  
  	ret = tb_port_get_link_width(port->dual_link_port);
  	if (ret == 1) {
  		ret = tb_port_set_link_width(port->dual_link_port, 2);
  		if (ret) {
  			tb_port_set_link_width(port, 1);
  			return ret;
  		}
  	}
  
  	port->bonded = true;
  	port->dual_link_port->bonded = true;
  
  	return 0;
  }
  
  /**
   * tb_port_lane_bonding_disable() - Disable bonding on port
   * @port: port to disable
   *
   * Disable bonding by setting the link width of the port and the
   * other port in case of dual link port.
   *
   */
  void tb_port_lane_bonding_disable(struct tb_port *port)
  {
  	port->dual_link_port->bonded = false;
  	port->bonded = false;
  
  	tb_port_set_link_width(port->dual_link_port, 1);
  	tb_port_set_link_width(port, 1);
  }
  
  static int tb_port_start_lane_initialization(struct tb_port *port)
  {
  	int ret;
  
  	if (tb_switch_is_usb4(port->sw))
  		return 0;
  
  	ret = tb_lc_start_lane_initialization(port);
  	return ret == -EINVAL ? 0 : ret;
  }
  
  /**
   * tb_port_is_enabled() - Is the adapter port enabled
   * @port: Port to check
   */
  bool tb_port_is_enabled(struct tb_port *port)
  {
  	switch (port->config.type) {
  	case TB_TYPE_PCIE_UP:
  	case TB_TYPE_PCIE_DOWN:
  		return tb_pci_port_is_enabled(port);
  
  	case TB_TYPE_DP_HDMI_IN:
  	case TB_TYPE_DP_HDMI_OUT:
  		return tb_dp_port_is_enabled(port);
  
  	case TB_TYPE_USB3_UP:
  	case TB_TYPE_USB3_DOWN:
  		return tb_usb3_port_is_enabled(port);
  
  	default:
  		return false;
  	}
  }
  
  /**
   * tb_usb3_port_is_enabled() - Is the USB3 adapter port enabled
   * @port: USB3 adapter port to check
   */
  bool tb_usb3_port_is_enabled(struct tb_port *port)
  {
  	u32 data;
  
  	if (tb_port_read(port, &data, TB_CFG_PORT,
  			 port->cap_adap + ADP_USB3_CS_0, 1))
  		return false;
  
  	return !!(data & ADP_USB3_CS_0_PE);
  }
  
  /**
   * tb_usb3_port_enable() - Enable USB3 adapter port
   * @port: USB3 adapter port to enable
   * @enable: Enable/disable the USB3 adapter
   */
  int tb_usb3_port_enable(struct tb_port *port, bool enable)
  {
  	u32 word = enable ? (ADP_USB3_CS_0_PE | ADP_USB3_CS_0_V)
  			  : ADP_USB3_CS_0_V;
  
  	if (!port->cap_adap)
  		return -ENXIO;
  	return tb_port_write(port, &word, TB_CFG_PORT,
  			     port->cap_adap + ADP_USB3_CS_0, 1);
  }
  
  /**
   * tb_pci_port_is_enabled() - Is the PCIe adapter port enabled
   * @port: PCIe port to check
   */
  bool tb_pci_port_is_enabled(struct tb_port *port)
  {
  	u32 data;
  
  	if (tb_port_read(port, &data, TB_CFG_PORT,
  			 port->cap_adap + ADP_PCIE_CS_0, 1))
  		return false;
  
  	return !!(data & ADP_PCIE_CS_0_PE);
  }
  
  /**
   * tb_pci_port_enable() - Enable PCIe adapter port
   * @port: PCIe port to enable
   * @enable: Enable/disable the PCIe adapter
   */
  int tb_pci_port_enable(struct tb_port *port, bool enable)
  {
  	u32 word = enable ? ADP_PCIE_CS_0_PE : 0x0;
  	if (!port->cap_adap)
  		return -ENXIO;
  	return tb_port_write(port, &word, TB_CFG_PORT,
  			     port->cap_adap + ADP_PCIE_CS_0, 1);
  }
  
  /**
   * tb_dp_port_hpd_is_active() - Is HPD already active
   * @port: DP out port to check
   *
   * Checks if the DP OUT adapter port has HDP bit already set.
   */
  int tb_dp_port_hpd_is_active(struct tb_port *port)
  {
  	u32 data;
  	int ret;
  
  	ret = tb_port_read(port, &data, TB_CFG_PORT,
  			   port->cap_adap + ADP_DP_CS_2, 1);
  	if (ret)
  		return ret;
  
  	return !!(data & ADP_DP_CS_2_HDP);
  }
  
  /**
   * tb_dp_port_hpd_clear() - Clear HPD from DP IN port
   * @port: Port to clear HPD
   *
   * If the DP IN port has HDP set, this function can be used to clear it.
   */
  int tb_dp_port_hpd_clear(struct tb_port *port)
  {
  	u32 data;
  	int ret;
  
  	ret = tb_port_read(port, &data, TB_CFG_PORT,
  			   port->cap_adap + ADP_DP_CS_3, 1);
  	if (ret)
  		return ret;
  
  	data |= ADP_DP_CS_3_HDPC;
  	return tb_port_write(port, &data, TB_CFG_PORT,
  			     port->cap_adap + ADP_DP_CS_3, 1);
  }
  
  /**
   * tb_dp_port_set_hops() - Set video/aux Hop IDs for DP port
   * @port: DP IN/OUT port to set hops
   * @video: Video Hop ID
   * @aux_tx: AUX TX Hop ID
   * @aux_rx: AUX RX Hop ID
   *
   * Programs specified Hop IDs for DP IN/OUT port.
   */
  int tb_dp_port_set_hops(struct tb_port *port, unsigned int video,
  			unsigned int aux_tx, unsigned int aux_rx)
  {
  	u32 data[2];
  	int ret;
  
  	ret = tb_port_read(port, data, TB_CFG_PORT,
  			   port->cap_adap + ADP_DP_CS_0, ARRAY_SIZE(data));
  	if (ret)
  		return ret;
  
  	data[0] &= ~ADP_DP_CS_0_VIDEO_HOPID_MASK;
  	data[1] &= ~ADP_DP_CS_1_AUX_RX_HOPID_MASK;
  	data[1] &= ~ADP_DP_CS_1_AUX_RX_HOPID_MASK;
  
  	data[0] |= (video << ADP_DP_CS_0_VIDEO_HOPID_SHIFT) &
  		ADP_DP_CS_0_VIDEO_HOPID_MASK;
  	data[1] |= aux_tx & ADP_DP_CS_1_AUX_TX_HOPID_MASK;
  	data[1] |= (aux_rx << ADP_DP_CS_1_AUX_RX_HOPID_SHIFT) &
  		ADP_DP_CS_1_AUX_RX_HOPID_MASK;
  
  	return tb_port_write(port, data, TB_CFG_PORT,
  			     port->cap_adap + ADP_DP_CS_0, ARRAY_SIZE(data));
  }
  
  /**
   * tb_dp_port_is_enabled() - Is DP adapter port enabled
   * @port: DP adapter port to check
   */
  bool tb_dp_port_is_enabled(struct tb_port *port)
  {
  	u32 data[2];
  
  	if (tb_port_read(port, data, TB_CFG_PORT, port->cap_adap + ADP_DP_CS_0,
  			 ARRAY_SIZE(data)))
  		return false;
  
  	return !!(data[0] & (ADP_DP_CS_0_VE | ADP_DP_CS_0_AE));
  }
  
  /**
   * tb_dp_port_enable() - Enables/disables DP paths of a port
   * @port: DP IN/OUT port
   * @enable: Enable/disable DP path
   *
   * Once Hop IDs are programmed DP paths can be enabled or disabled by
   * calling this function.
   */
  int tb_dp_port_enable(struct tb_port *port, bool enable)
  {
  	u32 data[2];
  	int ret;
  
  	ret = tb_port_read(port, data, TB_CFG_PORT,
  			  port->cap_adap + ADP_DP_CS_0, ARRAY_SIZE(data));
  	if (ret)
  		return ret;
  
  	if (enable)
  		data[0] |= ADP_DP_CS_0_VE | ADP_DP_CS_0_AE;
  	else
  		data[0] &= ~(ADP_DP_CS_0_VE | ADP_DP_CS_0_AE);
  
  	return tb_port_write(port, data, TB_CFG_PORT,
  			     port->cap_adap + ADP_DP_CS_0, ARRAY_SIZE(data));
  }
  
  /* switch utility functions */
  
  static const char *tb_switch_generation_name(const struct tb_switch *sw)
  {
  	switch (sw->generation) {
  	case 1:
  		return "Thunderbolt 1";
  	case 2:
  		return "Thunderbolt 2";
  	case 3:
  		return "Thunderbolt 3";
  	case 4:
  		return "USB4";
  	default:
  		return "Unknown";
  	}
  }
  
  static void tb_dump_switch(const struct tb *tb, const struct tb_switch *sw)
  {
  	const struct tb_regs_switch_header *regs = &sw->config;
  
  	tb_dbg(tb, " %s Switch: %x:%x (Revision: %d, TB Version: %d)\n",
  	       tb_switch_generation_name(sw), regs->vendor_id, regs->device_id,
  	       regs->revision, regs->thunderbolt_version);
  	tb_dbg(tb, "  Max Port Number: %d\n", regs->max_port_number);
  	tb_dbg(tb, "  Config:\n");
  	tb_dbg(tb,
  		"   Upstream Port Number: %d Depth: %d Route String: %#llx Enabled: %d, PlugEventsDelay: %dms\n",
  	       regs->upstream_port_number, regs->depth,
  	       (((u64) regs->route_hi) << 32) | regs->route_lo,
  	       regs->enabled, regs->plug_events_delay);
  	tb_dbg(tb, "   unknown1: %#x unknown4: %#x\n",
  	       regs->__unknown1, regs->__unknown4);
  }
  
  /**
   * tb_switch_reset() - reconfigure route, enable and send TB_CFG_PKG_RESET
   * @sw: Switch to reset
   *
   * Return: Returns 0 on success or an error code on failure.
   */
  int tb_switch_reset(struct tb_switch *sw)
  {
  	struct tb_cfg_result res;
  
  	if (sw->generation > 1)
  		return 0;
  
  	tb_sw_dbg(sw, "resetting switch\n");
  
  	res.err = tb_sw_write(sw, ((u32 *) &sw->config) + 2,
  			      TB_CFG_SWITCH, 2, 2);
  	if (res.err)
  		return res.err;
  	res = tb_cfg_reset(sw->tb->ctl, tb_route(sw));
  	if (res.err > 0)
  		return -EIO;
  	return res.err;
  }
  
  /*
   * tb_plug_events_active() - enable/disable plug events on a switch
   *
   * Also configures a sane plug_events_delay of 255ms.
   *
   * Return: Returns 0 on success or an error code on failure.
   */
  static int tb_plug_events_active(struct tb_switch *sw, bool active)
  {
  	u32 data;
  	int res;
  
  	if (tb_switch_is_icm(sw) || tb_switch_is_usb4(sw))
  		return 0;
  
  	sw->config.plug_events_delay = 0xff;
  	res = tb_sw_write(sw, ((u32 *) &sw->config) + 4, TB_CFG_SWITCH, 4, 1);
  	if (res)
  		return res;
  
  	res = tb_sw_read(sw, &data, TB_CFG_SWITCH, sw->cap_plug_events + 1, 1);
  	if (res)
  		return res;
  
  	if (active) {
  		data = data & 0xFFFFFF83;
  		switch (sw->config.device_id) {
  		case PCI_DEVICE_ID_INTEL_LIGHT_RIDGE:
  		case PCI_DEVICE_ID_INTEL_EAGLE_RIDGE:
  		case PCI_DEVICE_ID_INTEL_PORT_RIDGE:
  			break;
  		default:
  			data |= 4;
  		}
  	} else {
  		data = data | 0x7c;
  	}
  	return tb_sw_write(sw, &data, TB_CFG_SWITCH,
  			   sw->cap_plug_events + 1, 1);
  }
  
  static ssize_t authorized_show(struct device *dev,
  			       struct device_attribute *attr,
  			       char *buf)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  
  	return sprintf(buf, "%u\n", sw->authorized);
  }
  
  static int disapprove_switch(struct device *dev, void *not_used)
  {
  	struct tb_switch *sw;
  
  	sw = tb_to_switch(dev);
  	if (sw && sw->authorized) {
  		int ret;
  
  		/* First children */
  		ret = device_for_each_child_reverse(&sw->dev, NULL, disapprove_switch);
  		if (ret)
  			return ret;
  
  		ret = tb_domain_disapprove_switch(sw->tb, sw);
  		if (ret)
  			return ret;
  
  		sw->authorized = 0;
  		kobject_uevent(&sw->dev.kobj, KOBJ_CHANGE);
  	}
  
  	return 0;
  }
  
  static int tb_switch_set_authorized(struct tb_switch *sw, unsigned int val)
  {
  	int ret = -EINVAL;
  
  	if (!mutex_trylock(&sw->tb->lock))
  		return restart_syscall();
  
  	if (!!sw->authorized == !!val)
  		goto unlock;
  
  	switch (val) {
  	/* Disapprove switch */
  	case 0:
  		if (tb_route(sw)) {
  			ret = disapprove_switch(&sw->dev, NULL);
  			goto unlock;
  		}
  		break;
  
  	/* Approve switch */
  	case 1:
  		if (sw->key)
  			ret = tb_domain_approve_switch_key(sw->tb, sw);
  		else
  			ret = tb_domain_approve_switch(sw->tb, sw);
  		break;
  
  	/* Challenge switch */
  	case 2:
  		if (sw->key)
  			ret = tb_domain_challenge_switch_key(sw->tb, sw);
  		break;
  
  	default:
  		break;
  	}
  
  	if (!ret) {
  		sw->authorized = val;
  		/* Notify status change to the userspace */
  		kobject_uevent(&sw->dev.kobj, KOBJ_CHANGE);
  	}
  
  unlock:
  	mutex_unlock(&sw->tb->lock);
  	return ret;
  }
  
  static ssize_t authorized_store(struct device *dev,
  				struct device_attribute *attr,
  				const char *buf, size_t count)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  	unsigned int val;
  	ssize_t ret;
  
  	ret = kstrtouint(buf, 0, &val);
  	if (ret)
  		return ret;
  	if (val > 2)
  		return -EINVAL;
  
  	pm_runtime_get_sync(&sw->dev);
  	ret = tb_switch_set_authorized(sw, val);
  	pm_runtime_mark_last_busy(&sw->dev);
  	pm_runtime_put_autosuspend(&sw->dev);
  
  	return ret ? ret : count;
  }
  static DEVICE_ATTR_RW(authorized);
  
  static ssize_t boot_show(struct device *dev, struct device_attribute *attr,
  			 char *buf)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  
  	return sprintf(buf, "%u\n", sw->boot);
  }
  static DEVICE_ATTR_RO(boot);
  
  static ssize_t device_show(struct device *dev, struct device_attribute *attr,
  			   char *buf)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  
  	return sprintf(buf, "%#x\n", sw->device);
  }
  static DEVICE_ATTR_RO(device);
  
  static ssize_t
  device_name_show(struct device *dev, struct device_attribute *attr, char *buf)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  
  	return sprintf(buf, "%s\n", sw->device_name ? sw->device_name : "");
  }
  static DEVICE_ATTR_RO(device_name);
  
  static ssize_t
  generation_show(struct device *dev, struct device_attribute *attr, char *buf)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  
  	return sprintf(buf, "%u\n", sw->generation);
  }
  static DEVICE_ATTR_RO(generation);
  
  static ssize_t key_show(struct device *dev, struct device_attribute *attr,
  			char *buf)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  	ssize_t ret;
  
  	if (!mutex_trylock(&sw->tb->lock))
  		return restart_syscall();
  
  	if (sw->key)
  		ret = sprintf(buf, "%*phN\n", TB_SWITCH_KEY_SIZE, sw->key);
  	else
  		ret = sprintf(buf, "\n");
  
  	mutex_unlock(&sw->tb->lock);
  	return ret;
  }
  
  static ssize_t key_store(struct device *dev, struct device_attribute *attr,
  			 const char *buf, size_t count)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  	u8 key[TB_SWITCH_KEY_SIZE];
  	ssize_t ret = count;
  	bool clear = false;
  
  	if (!strcmp(buf, "\n"))
  		clear = true;
  	else if (hex2bin(key, buf, sizeof(key)))
  		return -EINVAL;
  
  	if (!mutex_trylock(&sw->tb->lock))
  		return restart_syscall();
  
  	if (sw->authorized) {
  		ret = -EBUSY;
  	} else {
  		kfree(sw->key);
  		if (clear) {
  			sw->key = NULL;
  		} else {
  			sw->key = kmemdup(key, sizeof(key), GFP_KERNEL);
  			if (!sw->key)
  				ret = -ENOMEM;
  		}
  	}
  
  	mutex_unlock(&sw->tb->lock);
  	return ret;
  }
  static DEVICE_ATTR(key, 0600, key_show, key_store);
  
  static ssize_t speed_show(struct device *dev, struct device_attribute *attr,
  			  char *buf)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  
  	return sprintf(buf, "%u.0 Gb/s\n", sw->link_speed);
  }
  
  /*
   * Currently all lanes must run at the same speed but we expose here
   * both directions to allow possible asymmetric links in the future.
   */
  static DEVICE_ATTR(rx_speed, 0444, speed_show, NULL);
  static DEVICE_ATTR(tx_speed, 0444, speed_show, NULL);
  
  static ssize_t lanes_show(struct device *dev, struct device_attribute *attr,
  			  char *buf)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  
  	return sprintf(buf, "%u\n", sw->link_width);
  }
  
  /*
   * Currently link has same amount of lanes both directions (1 or 2) but
   * expose them separately to allow possible asymmetric links in the future.
   */
  static DEVICE_ATTR(rx_lanes, 0444, lanes_show, NULL);
  static DEVICE_ATTR(tx_lanes, 0444, lanes_show, NULL);
  
  static ssize_t nvm_authenticate_show(struct device *dev,
  	struct device_attribute *attr, char *buf)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  	u32 status;
  
  	nvm_get_auth_status(sw, &status);
  	return sprintf(buf, "%#x\n", status);
  }
  
  static ssize_t nvm_authenticate_sysfs(struct device *dev, const char *buf,
  				      bool disconnect)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  	int val;
  	int ret;
  
  	pm_runtime_get_sync(&sw->dev);
  
  	if (!mutex_trylock(&sw->tb->lock)) {
  		ret = restart_syscall();
  		goto exit_rpm;
  	}
  
  	/* If NVMem devices are not yet added */
  	if (!sw->nvm) {
  		ret = -EAGAIN;
  		goto exit_unlock;
  	}
  
  	ret = kstrtoint(buf, 10, &val);
  	if (ret)
  		goto exit_unlock;
  
  	/* Always clear the authentication status */
  	nvm_clear_auth_status(sw);
  
  	if (val > 0) {
  		if (!sw->nvm->flushed) {
  			if (!sw->nvm->buf) {
  				ret = -EINVAL;
  				goto exit_unlock;
  			}
  
  			ret = nvm_validate_and_write(sw);
  			if (ret || val == WRITE_ONLY)
  				goto exit_unlock;
  		}
  		if (val == WRITE_AND_AUTHENTICATE) {
  			if (disconnect) {
  				ret = tb_lc_force_power(sw);
  			} else {
  				sw->nvm->authenticating = true;
  				ret = nvm_authenticate(sw);
  			}
  		}
  	}
  
  exit_unlock:
  	mutex_unlock(&sw->tb->lock);
  exit_rpm:
  	pm_runtime_mark_last_busy(&sw->dev);
  	pm_runtime_put_autosuspend(&sw->dev);
  
  	return ret;
  }
  
  static ssize_t nvm_authenticate_store(struct device *dev,
  	struct device_attribute *attr, const char *buf, size_t count)
  {
  	int ret = nvm_authenticate_sysfs(dev, buf, false);
  	if (ret)
  		return ret;
  	return count;
  }
  static DEVICE_ATTR_RW(nvm_authenticate);
  
  static ssize_t nvm_authenticate_on_disconnect_show(struct device *dev,
  	struct device_attribute *attr, char *buf)
  {
  	return nvm_authenticate_show(dev, attr, buf);
  }
  
  static ssize_t nvm_authenticate_on_disconnect_store(struct device *dev,
  	struct device_attribute *attr, const char *buf, size_t count)
  {
  	int ret;
  
  	ret = nvm_authenticate_sysfs(dev, buf, true);
  	return ret ? ret : count;
  }
  static DEVICE_ATTR_RW(nvm_authenticate_on_disconnect);
  
  static ssize_t nvm_version_show(struct device *dev,
  				struct device_attribute *attr, char *buf)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  	int ret;
  
  	if (!mutex_trylock(&sw->tb->lock))
  		return restart_syscall();
  
  	if (sw->safe_mode)
  		ret = -ENODATA;
  	else if (!sw->nvm)
  		ret = -EAGAIN;
  	else
  		ret = sprintf(buf, "%x.%x\n", sw->nvm->major, sw->nvm->minor);
  
  	mutex_unlock(&sw->tb->lock);
  
  	return ret;
  }
  static DEVICE_ATTR_RO(nvm_version);
  
  static ssize_t vendor_show(struct device *dev, struct device_attribute *attr,
  			   char *buf)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  
  	return sprintf(buf, "%#x\n", sw->vendor);
  }
  static DEVICE_ATTR_RO(vendor);
  
  static ssize_t
  vendor_name_show(struct device *dev, struct device_attribute *attr, char *buf)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  
  	return sprintf(buf, "%s\n", sw->vendor_name ? sw->vendor_name : "");
  }
  static DEVICE_ATTR_RO(vendor_name);
  
  static ssize_t unique_id_show(struct device *dev, struct device_attribute *attr,
  			      char *buf)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  
  	return sprintf(buf, "%pUb\n", sw->uuid);
  }
  static DEVICE_ATTR_RO(unique_id);
  
  static struct attribute *switch_attrs[] = {
  	&dev_attr_authorized.attr,
  	&dev_attr_boot.attr,
  	&dev_attr_device.attr,
  	&dev_attr_device_name.attr,
  	&dev_attr_generation.attr,
  	&dev_attr_key.attr,
  	&dev_attr_nvm_authenticate.attr,
  	&dev_attr_nvm_authenticate_on_disconnect.attr,
  	&dev_attr_nvm_version.attr,
  	&dev_attr_rx_speed.attr,
  	&dev_attr_rx_lanes.attr,
  	&dev_attr_tx_speed.attr,
  	&dev_attr_tx_lanes.attr,
  	&dev_attr_vendor.attr,
  	&dev_attr_vendor_name.attr,
  	&dev_attr_unique_id.attr,
  	NULL,
  };
  
  static umode_t switch_attr_is_visible(struct kobject *kobj,
  				      struct attribute *attr, int n)
  {
  	struct device *dev = kobj_to_dev(kobj);
  	struct tb_switch *sw = tb_to_switch(dev);
  
  	if (attr == &dev_attr_authorized.attr) {
  		if (sw->tb->security_level == TB_SECURITY_NOPCIE ||
  		    sw->tb->security_level == TB_SECURITY_DPONLY)
  			return 0;
  	} else if (attr == &dev_attr_device.attr) {
  		if (!sw->device)
  			return 0;
  	} else if (attr == &dev_attr_device_name.attr) {
  		if (!sw->device_name)
  			return 0;
  	} else if (attr == &dev_attr_vendor.attr)  {
  		if (!sw->vendor)
  			return 0;
  	} else if (attr == &dev_attr_vendor_name.attr)  {
  		if (!sw->vendor_name)
  			return 0;
  	} else if (attr == &dev_attr_key.attr) {
  		if (tb_route(sw) &&
  		    sw->tb->security_level == TB_SECURITY_SECURE &&
  		    sw->security_level == TB_SECURITY_SECURE)
  			return attr->mode;
  		return 0;
  	} else if (attr == &dev_attr_rx_speed.attr ||
  		   attr == &dev_attr_rx_lanes.attr ||
  		   attr == &dev_attr_tx_speed.attr ||
  		   attr == &dev_attr_tx_lanes.attr) {
  		if (tb_route(sw))
  			return attr->mode;
  		return 0;
  	} else if (attr == &dev_attr_nvm_authenticate.attr) {
  		if (nvm_upgradeable(sw))
  			return attr->mode;
  		return 0;
  	} else if (attr == &dev_attr_nvm_version.attr) {
  		if (nvm_readable(sw))
  			return attr->mode;
  		return 0;
  	} else if (attr == &dev_attr_boot.attr) {
  		if (tb_route(sw))
  			return attr->mode;
  		return 0;
  	} else if (attr == &dev_attr_nvm_authenticate_on_disconnect.attr) {
  		if (sw->quirks & QUIRK_FORCE_POWER_LINK_CONTROLLER)
  			return attr->mode;
  		return 0;
  	}
  
  	return sw->safe_mode ? 0 : attr->mode;
  }
  
  static const struct attribute_group switch_group = {
  	.is_visible = switch_attr_is_visible,
  	.attrs = switch_attrs,
  };
  
  static const struct attribute_group *switch_groups[] = {
  	&switch_group,
  	NULL,
  };
  
  static void tb_switch_release(struct device *dev)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  	struct tb_port *port;
  
  	dma_port_free(sw->dma_port);
  
  	tb_switch_for_each_port(sw, port) {
  		ida_destroy(&port->in_hopids);
  		ida_destroy(&port->out_hopids);
  	}
  
  	kfree(sw->uuid);
  	kfree(sw->device_name);
  	kfree(sw->vendor_name);
  	kfree(sw->ports);
  	kfree(sw->drom);
  	kfree(sw->key);
  	kfree(sw);
  }
  
  static int tb_switch_uevent(struct device *dev, struct kobj_uevent_env *env)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  	const char *type;
  
  	if (sw->config.thunderbolt_version == USB4_VERSION_1_0) {
  		if (add_uevent_var(env, "USB4_VERSION=1.0"))
  			return -ENOMEM;
  	}
  
  	if (!tb_route(sw)) {
  		type = "host";
  	} else {
  		const struct tb_port *port;
  		bool hub = false;
  
  		/* Device is hub if it has any downstream ports */
  		tb_switch_for_each_port(sw, port) {
  			if (!port->disabled && !tb_is_upstream_port(port) &&
  			     tb_port_is_null(port)) {
  				hub = true;
  				break;
  			}
  		}
  
  		type = hub ? "hub" : "device";
  	}
  
  	if (add_uevent_var(env, "USB4_TYPE=%s", type))
  		return -ENOMEM;
  	return 0;
  }
  
  /*
   * Currently only need to provide the callbacks. Everything else is handled
   * in the connection manager.
   */
  static int __maybe_unused tb_switch_runtime_suspend(struct device *dev)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  	const struct tb_cm_ops *cm_ops = sw->tb->cm_ops;
  
  	if (cm_ops->runtime_suspend_switch)
  		return cm_ops->runtime_suspend_switch(sw);
  
  	return 0;
  }
  
  static int __maybe_unused tb_switch_runtime_resume(struct device *dev)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  	const struct tb_cm_ops *cm_ops = sw->tb->cm_ops;
  
  	if (cm_ops->runtime_resume_switch)
  		return cm_ops->runtime_resume_switch(sw);
  	return 0;
  }
  
  static const struct dev_pm_ops tb_switch_pm_ops = {
  	SET_RUNTIME_PM_OPS(tb_switch_runtime_suspend, tb_switch_runtime_resume,
  			   NULL)
  };
  
  struct device_type tb_switch_type = {
  	.name = "thunderbolt_device",
  	.release = tb_switch_release,
  	.uevent = tb_switch_uevent,
  	.pm = &tb_switch_pm_ops,
  };
  
  static int tb_switch_get_generation(struct tb_switch *sw)
  {
  	switch (sw->config.device_id) {
  	case PCI_DEVICE_ID_INTEL_LIGHT_RIDGE:
  	case PCI_DEVICE_ID_INTEL_EAGLE_RIDGE:
  	case PCI_DEVICE_ID_INTEL_LIGHT_PEAK:
  	case PCI_DEVICE_ID_INTEL_CACTUS_RIDGE_2C:
  	case PCI_DEVICE_ID_INTEL_CACTUS_RIDGE_4C:
  	case PCI_DEVICE_ID_INTEL_PORT_RIDGE:
  	case PCI_DEVICE_ID_INTEL_REDWOOD_RIDGE_2C_BRIDGE:
  	case PCI_DEVICE_ID_INTEL_REDWOOD_RIDGE_4C_BRIDGE:
  		return 1;
  
  	case PCI_DEVICE_ID_INTEL_WIN_RIDGE_2C_BRIDGE:
  	case PCI_DEVICE_ID_INTEL_FALCON_RIDGE_2C_BRIDGE:
  	case PCI_DEVICE_ID_INTEL_FALCON_RIDGE_4C_BRIDGE:
  		return 2;
  
  	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_LP_BRIDGE:
  	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_2C_BRIDGE:
  	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_4C_BRIDGE:
  	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_2C_BRIDGE:
  	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_4C_BRIDGE:
  	case PCI_DEVICE_ID_INTEL_TITAN_RIDGE_2C_BRIDGE:
  	case PCI_DEVICE_ID_INTEL_TITAN_RIDGE_4C_BRIDGE:
  	case PCI_DEVICE_ID_INTEL_TITAN_RIDGE_DD_BRIDGE:
  	case PCI_DEVICE_ID_INTEL_ICL_NHI0:
  	case PCI_DEVICE_ID_INTEL_ICL_NHI1:
  		return 3;
  
  	default:
  		if (tb_switch_is_usb4(sw))
  			return 4;
  
  		/*
  		 * For unknown switches assume generation to be 1 to be
  		 * on the safe side.
  		 */
  		tb_sw_warn(sw, "unsupported switch device id %#x\n",
  			   sw->config.device_id);
  		return 1;
  	}
  }
  
  static bool tb_switch_exceeds_max_depth(const struct tb_switch *sw, int depth)
  {
  	int max_depth;
  
  	if (tb_switch_is_usb4(sw) ||
  	    (sw->tb->root_switch && tb_switch_is_usb4(sw->tb->root_switch)))
  		max_depth = USB4_SWITCH_MAX_DEPTH;
  	else
  		max_depth = TB_SWITCH_MAX_DEPTH;
  
  	return depth > max_depth;
  }
  
  /**
   * tb_switch_alloc() - allocate a switch
   * @tb: Pointer to the owning domain
   * @parent: Parent device for this switch
   * @route: Route string for this switch
   *
   * Allocates and initializes a switch. Will not upload configuration to
   * the switch. For that you need to call tb_switch_configure()
   * separately. The returned switch should be released by calling
   * tb_switch_put().
   *
   * Return: Pointer to the allocated switch or ERR_PTR() in case of
   * failure.
   */
  struct tb_switch *tb_switch_alloc(struct tb *tb, struct device *parent,
  				  u64 route)
  {
  	struct tb_switch *sw;
  	int upstream_port;
  	int i, ret, depth;
  
  	/* Unlock the downstream port so we can access the switch below */
  	if (route) {
  		struct tb_switch *parent_sw = tb_to_switch(parent);
  		struct tb_port *down;
  
  		down = tb_port_at(route, parent_sw);
  		tb_port_unlock(down);
  	}
  
  	depth = tb_route_length(route);
  
  	upstream_port = tb_cfg_get_upstream_port(tb->ctl, route);
  	if (upstream_port < 0)
  		return ERR_PTR(upstream_port);
  
  	sw = kzalloc(sizeof(*sw), GFP_KERNEL);
  	if (!sw)
  		return ERR_PTR(-ENOMEM);
  
  	sw->tb = tb;
  	ret = tb_cfg_read(tb->ctl, &sw->config, route, 0, TB_CFG_SWITCH, 0, 5);
  	if (ret)
  		goto err_free_sw_ports;
  
  	sw->generation = tb_switch_get_generation(sw);
  
  	tb_dbg(tb, "current switch config:\n");
  	tb_dump_switch(tb, sw);
  
  	/* configure switch */
  	sw->config.upstream_port_number = upstream_port;
  	sw->config.depth = depth;
  	sw->config.route_hi = upper_32_bits(route);
  	sw->config.route_lo = lower_32_bits(route);
  	sw->config.enabled = 0;
  
  	/* Make sure we do not exceed maximum topology limit */
  	if (tb_switch_exceeds_max_depth(sw, depth)) {
  		ret = -EADDRNOTAVAIL;
  		goto err_free_sw_ports;
  	}
  
  	/* initialize ports */
  	sw->ports = kcalloc(sw->config.max_port_number + 1, sizeof(*sw->ports),
  				GFP_KERNEL);
  	if (!sw->ports) {
  		ret = -ENOMEM;
  		goto err_free_sw_ports;
  	}
  
  	for (i = 0; i <= sw->config.max_port_number; i++) {
  		/* minimum setup for tb_find_cap and tb_drom_read to work */
  		sw->ports[i].sw = sw;
  		sw->ports[i].port = i;
  
  		/* Control port does not need HopID allocation */
  		if (i) {
  			ida_init(&sw->ports[i].in_hopids);
  			ida_init(&sw->ports[i].out_hopids);
  		}
  	}
  
  	ret = tb_switch_find_vse_cap(sw, TB_VSE_CAP_PLUG_EVENTS);
  	if (ret > 0)
  		sw->cap_plug_events = ret;
  
  	ret = tb_switch_find_vse_cap(sw, TB_VSE_CAP_LINK_CONTROLLER);
  	if (ret > 0)
  		sw->cap_lc = ret;
  
  	/* Root switch is always authorized */
  	if (!route)
  		sw->authorized = true;
  
  	device_initialize(&sw->dev);
  	sw->dev.parent = parent;
  	sw->dev.bus = &tb_bus_type;
  	sw->dev.type = &tb_switch_type;
  	sw->dev.groups = switch_groups;
  	dev_set_name(&sw->dev, "%u-%llx", tb->index, tb_route(sw));
  
  	return sw;
  
  err_free_sw_ports:
  	kfree(sw->ports);
  	kfree(sw);
  
  	return ERR_PTR(ret);
  }
  
  /**
   * tb_switch_alloc_safe_mode() - allocate a switch that is in safe mode
   * @tb: Pointer to the owning domain
   * @parent: Parent device for this switch
   * @route: Route string for this switch
   *
   * This creates a switch in safe mode. This means the switch pretty much
   * lacks all capabilities except DMA configuration port before it is
   * flashed with a valid NVM firmware.
   *
   * The returned switch must be released by calling tb_switch_put().
   *
   * Return: Pointer to the allocated switch or ERR_PTR() in case of failure
   */
  struct tb_switch *
  tb_switch_alloc_safe_mode(struct tb *tb, struct device *parent, u64 route)
  {
  	struct tb_switch *sw;
  
  	sw = kzalloc(sizeof(*sw), GFP_KERNEL);
  	if (!sw)
  		return ERR_PTR(-ENOMEM);
  
  	sw->tb = tb;
  	sw->config.depth = tb_route_length(route);
  	sw->config.route_hi = upper_32_bits(route);
  	sw->config.route_lo = lower_32_bits(route);
  	sw->safe_mode = true;
  
  	device_initialize(&sw->dev);
  	sw->dev.parent = parent;
  	sw->dev.bus = &tb_bus_type;
  	sw->dev.type = &tb_switch_type;
  	sw->dev.groups = switch_groups;
  	dev_set_name(&sw->dev, "%u-%llx", tb->index, tb_route(sw));
  
  	return sw;
  }
  
  /**
   * tb_switch_configure() - Uploads configuration to the switch
   * @sw: Switch to configure
   *
   * Call this function before the switch is added to the system. It will
   * upload configuration to the switch and makes it available for the
   * connection manager to use. Can be called to the switch again after
   * resume from low power states to re-initialize it.
   *
   * Return: %0 in case of success and negative errno in case of failure
   */
  int tb_switch_configure(struct tb_switch *sw)
  {
  	struct tb *tb = sw->tb;
  	u64 route;
  	int ret;
  
  	route = tb_route(sw);
  
  	tb_dbg(tb, "%s Switch at %#llx (depth: %d, up port: %d)\n",
  	       sw->config.enabled ? "restoring" : "initializing", route,
  	       tb_route_length(route), sw->config.upstream_port_number);
  
  	sw->config.enabled = 1;
  
  	if (tb_switch_is_usb4(sw)) {
  		/*
  		 * For USB4 devices, we need to program the CM version
  		 * accordingly so that it knows to expose all the
  		 * additional capabilities.
  		 */
  		sw->config.cmuv = USB4_VERSION_1_0;
  
  		/* Enumerate the switch */
  		ret = tb_sw_write(sw, (u32 *)&sw->config + 1, TB_CFG_SWITCH,
  				  ROUTER_CS_1, 4);
  		if (ret)
  			return ret;
  
  		ret = usb4_switch_setup(sw);
  	} else {
  		if (sw->config.vendor_id != PCI_VENDOR_ID_INTEL)
  			tb_sw_warn(sw, "unknown switch vendor id %#x\n",
  				   sw->config.vendor_id);
  
  		if (!sw->cap_plug_events) {
  			tb_sw_warn(sw, "cannot find TB_VSE_CAP_PLUG_EVENTS aborting\n");
  			return -ENODEV;
  		}
  
  		/* Enumerate the switch */
  		ret = tb_sw_write(sw, (u32 *)&sw->config + 1, TB_CFG_SWITCH,
  				  ROUTER_CS_1, 3);
  	}
  	if (ret)
  		return ret;
  
  	return tb_plug_events_active(sw, true);
  }
  
  static int tb_switch_set_uuid(struct tb_switch *sw)
  {
  	bool uid = false;
  	u32 uuid[4];
  	int ret;
  
  	if (sw->uuid)
  		return 0;
  
  	if (tb_switch_is_usb4(sw)) {
  		ret = usb4_switch_read_uid(sw, &sw->uid);
  		if (ret)
  			return ret;
  		uid = true;
  	} else {
  		/*
  		 * The newer controllers include fused UUID as part of
  		 * link controller specific registers
  		 */
  		ret = tb_lc_read_uuid(sw, uuid);
  		if (ret) {
  			if (ret != -EINVAL)
  				return ret;
  			uid = true;
  		}
  	}
  
  	if (uid) {
  		/*
  		 * ICM generates UUID based on UID and fills the upper
  		 * two words with ones. This is not strictly following
  		 * UUID format but we want to be compatible with it so
  		 * we do the same here.
  		 */
  		uuid[0] = sw->uid & 0xffffffff;
  		uuid[1] = (sw->uid >> 32) & 0xffffffff;
  		uuid[2] = 0xffffffff;
  		uuid[3] = 0xffffffff;
  	}
  
  	sw->uuid = kmemdup(uuid, sizeof(uuid), GFP_KERNEL);
  	if (!sw->uuid)
  		return -ENOMEM;
  	return 0;
  }
  
  static int tb_switch_add_dma_port(struct tb_switch *sw)
  {
  	u32 status;
  	int ret;
  
  	switch (sw->generation) {
  	case 2:
  		/* Only root switch can be upgraded */
  		if (tb_route(sw))
  			return 0;
  
  		fallthrough;
  	case 3:
  	case 4:
  		ret = tb_switch_set_uuid(sw);
  		if (ret)
  			return ret;
  		break;
  
  	default:
  		/*
  		 * DMA port is the only thing available when the switch
  		 * is in safe mode.
  		 */
  		if (!sw->safe_mode)
  			return 0;
  		break;
  	}
  
  	if (sw->no_nvm_upgrade)
  		return 0;
  
  	if (tb_switch_is_usb4(sw)) {
  		ret = usb4_switch_nvm_authenticate_status(sw, &status);
  		if (ret)
  			return ret;
  
  		if (status) {
  			tb_sw_info(sw, "switch flash authentication failed\n");
  			nvm_set_auth_status(sw, status);
  		}
  
  		return 0;
  	}
  
  	/* Root switch DMA port requires running firmware */
  	if (!tb_route(sw) && !tb_switch_is_icm(sw))
  		return 0;
  
  	sw->dma_port = dma_port_alloc(sw);
  	if (!sw->dma_port)
  		return 0;
  
  	/*
  	 * If there is status already set then authentication failed
  	 * when the dma_port_flash_update_auth() returned. Power cycling
  	 * is not needed (it was done already) so only thing we do here
  	 * is to unblock runtime PM of the root port.
  	 */
  	nvm_get_auth_status(sw, &status);
  	if (status) {
  		if (!tb_route(sw))
  			nvm_authenticate_complete_dma_port(sw);
  		return 0;
  	}
  
  	/*
  	 * Check status of the previous flash authentication. If there
  	 * is one we need to power cycle the switch in any case to make
  	 * it functional again.
  	 */
  	ret = dma_port_flash_update_auth_status(sw->dma_port, &status);
  	if (ret <= 0)
  		return ret;
  
  	/* Now we can allow root port to suspend again */
  	if (!tb_route(sw))
  		nvm_authenticate_complete_dma_port(sw);
  
  	if (status) {
  		tb_sw_info(sw, "switch flash authentication failed\n");
  		nvm_set_auth_status(sw, status);
  	}
  
  	tb_sw_info(sw, "power cycling the switch now\n");
  	dma_port_power_cycle(sw->dma_port);
  
  	/*
  	 * We return error here which causes the switch adding failure.
  	 * It should appear back after power cycle is complete.
  	 */
  	return -ESHUTDOWN;
  }
  
  static void tb_switch_default_link_ports(struct tb_switch *sw)
  {
  	int i;
  
  	for (i = 1; i <= sw->config.max_port_number; i += 2) {
  		struct tb_port *port = &sw->ports[i];
  		struct tb_port *subordinate;
  
  		if (!tb_port_is_null(port))
  			continue;
  
  		/* Check for the subordinate port */
  		if (i == sw->config.max_port_number ||
  		    !tb_port_is_null(&sw->ports[i + 1]))
  			continue;
  
  		/* Link them if not already done so (by DROM) */
  		subordinate = &sw->ports[i + 1];
  		if (!port->dual_link_port && !subordinate->dual_link_port) {
  			port->link_nr = 0;
  			port->dual_link_port = subordinate;
  			subordinate->link_nr = 1;
  			subordinate->dual_link_port = port;
  
  			tb_sw_dbg(sw, "linked ports %d <-> %d\n",
  				  port->port, subordinate->port);
  		}
  	}
  }
  
  static bool tb_switch_lane_bonding_possible(struct tb_switch *sw)
  {
  	const struct tb_port *up = tb_upstream_port(sw);
  
  	if (!up->dual_link_port || !up->dual_link_port->remote)
  		return false;
  
  	if (tb_switch_is_usb4(sw))
  		return usb4_switch_lane_bonding_possible(sw);
  	return tb_lc_lane_bonding_possible(sw);
  }
  
  static int tb_switch_update_link_attributes(struct tb_switch *sw)
  {
  	struct tb_port *up;
  	bool change = false;
  	int ret;
  
  	if (!tb_route(sw) || tb_switch_is_icm(sw))
  		return 0;
  
  	up = tb_upstream_port(sw);
  
  	ret = tb_port_get_link_speed(up);
  	if (ret < 0)
  		return ret;
  	if (sw->link_speed != ret)
  		change = true;
  	sw->link_speed = ret;
  
  	ret = tb_port_get_link_width(up);
  	if (ret < 0)
  		return ret;
  	if (sw->link_width != ret)
  		change = true;
  	sw->link_width = ret;
  
  	/* Notify userspace that there is possible link attribute change */
  	if (device_is_registered(&sw->dev) && change)
  		kobject_uevent(&sw->dev.kobj, KOBJ_CHANGE);
  
  	return 0;
  }
  
  /**
   * tb_switch_lane_bonding_enable() - Enable lane bonding
   * @sw: Switch to enable lane bonding
   *
   * Connection manager can call this function to enable lane bonding of a
   * switch. If conditions are correct and both switches support the feature,
   * lanes are bonded. It is safe to call this to any switch.
   */
  int tb_switch_lane_bonding_enable(struct tb_switch *sw)
  {
  	struct tb_switch *parent = tb_to_switch(sw->dev.parent);
  	struct tb_port *up, *down;
  	u64 route = tb_route(sw);
  	int ret;
  
  	if (!route)
  		return 0;
  
  	if (!tb_switch_lane_bonding_possible(sw))
  		return 0;
  
  	up = tb_upstream_port(sw);
  	down = tb_port_at(route, parent);
  
  	if (!tb_port_is_width_supported(up, 2) ||
  	    !tb_port_is_width_supported(down, 2))
  		return 0;
  
  	ret = tb_port_lane_bonding_enable(up);
  	if (ret) {
  		tb_port_warn(up, "failed to enable lane bonding\n");
  		return ret;
  	}
  
  	ret = tb_port_lane_bonding_enable(down);
  	if (ret) {
  		tb_port_warn(down, "failed to enable lane bonding\n");
  		tb_port_lane_bonding_disable(up);
  		return ret;
  	}
  
  	tb_switch_update_link_attributes(sw);
  
  	tb_sw_dbg(sw, "lane bonding enabled\n");
  	return ret;
  }
  
  /**
   * tb_switch_lane_bonding_disable() - Disable lane bonding
   * @sw: Switch whose lane bonding to disable
   *
   * Disables lane bonding between @sw and parent. This can be called even
   * if lanes were not bonded originally.
   */
  void tb_switch_lane_bonding_disable(struct tb_switch *sw)
  {
  	struct tb_switch *parent = tb_to_switch(sw->dev.parent);
  	struct tb_port *up, *down;
  
  	if (!tb_route(sw))
  		return;
  
  	up = tb_upstream_port(sw);
  	if (!up->bonded)
  		return;
  
  	down = tb_port_at(tb_route(sw), parent);
  
  	tb_port_lane_bonding_disable(up);
  	tb_port_lane_bonding_disable(down);
  
  	tb_switch_update_link_attributes(sw);
  	tb_sw_dbg(sw, "lane bonding disabled\n");
  }
  
  /**
   * tb_switch_configure_link() - Set link configured
   * @sw: Switch whose link is configured
   *
   * Sets the link upstream from @sw configured (from both ends) so that
   * it will not be disconnected when the domain exits sleep. Can be
   * called for any switch.
   *
   * It is recommended that this is called after lane bonding is enabled.
   *
   * Returns %0 on success and negative errno in case of error.
   */
  int tb_switch_configure_link(struct tb_switch *sw)
  {
  	struct tb_port *up, *down;
  	int ret;
  
  	if (!tb_route(sw) || tb_switch_is_icm(sw))
  		return 0;
  
  	up = tb_upstream_port(sw);
  	if (tb_switch_is_usb4(up->sw))
  		ret = usb4_port_configure(up);
  	else
  		ret = tb_lc_configure_port(up);
  	if (ret)
  		return ret;
  
  	down = up->remote;
  	if (tb_switch_is_usb4(down->sw))
  		return usb4_port_configure(down);
  	return tb_lc_configure_port(down);
  }
  
  /**
   * tb_switch_unconfigure_link() - Unconfigure link
   * @sw: Switch whose link is unconfigured
   *
   * Sets the link unconfigured so the @sw will be disconnected if the
   * domain exists sleep.
   */
  void tb_switch_unconfigure_link(struct tb_switch *sw)
  {
  	struct tb_port *up, *down;
  
  	if (sw->is_unplugged)
  		return;
  	if (!tb_route(sw) || tb_switch_is_icm(sw))
  		return;
  
  	up = tb_upstream_port(sw);
  	if (tb_switch_is_usb4(up->sw))
  		usb4_port_unconfigure(up);
  	else
  		tb_lc_unconfigure_port(up);
  
  	down = up->remote;
  	if (tb_switch_is_usb4(down->sw))
  		usb4_port_unconfigure(down);
  	else
  		tb_lc_unconfigure_port(down);
  }
  
  /**
   * tb_switch_add() - Add a switch to the domain
   * @sw: Switch to add
   *
   * This is the last step in adding switch to the domain. It will read
   * identification information from DROM and initializes ports so that
   * they can be used to connect other switches. The switch will be
   * exposed to the userspace when this function successfully returns. To
   * remove and release the switch, call tb_switch_remove().
   *
   * Return: %0 in case of success and negative errno in case of failure
   */
  int tb_switch_add(struct tb_switch *sw)
  {
  	int i, ret;
  
  	/*
  	 * Initialize DMA control port now before we read DROM. Recent
  	 * host controllers have more complete DROM on NVM that includes
  	 * vendor and model identification strings which we then expose
  	 * to the userspace. NVM can be accessed through DMA
  	 * configuration based mailbox.
  	 */
  	ret = tb_switch_add_dma_port(sw);
  	if (ret) {
  		dev_err(&sw->dev, "failed to add DMA port\n");
  		return ret;
  	}
  
  	if (!sw->safe_mode) {
  		/* read drom */
  		ret = tb_drom_read(sw);
  		if (ret) {
  			dev_err(&sw->dev, "reading DROM failed\n");
  			return ret;
  		}
  		tb_sw_dbg(sw, "uid: %#llx\n", sw->uid);
  
  		tb_check_quirks(sw);
  
  		ret = tb_switch_set_uuid(sw);
  		if (ret) {
  			dev_err(&sw->dev, "failed to set UUID\n");
  			return ret;
  		}
  
  		for (i = 0; i <= sw->config.max_port_number; i++) {
  			if (sw->ports[i].disabled) {
  				tb_port_dbg(&sw->ports[i], "disabled by eeprom\n");
  				continue;
  			}
  			ret = tb_init_port(&sw->ports[i]);
  			if (ret) {
  				dev_err(&sw->dev, "failed to initialize port %d\n", i);
  				return ret;
  			}
  		}
  
  		tb_switch_default_link_ports(sw);
  
  		ret = tb_switch_update_link_attributes(sw);
  		if (ret)
  			return ret;
  
  		ret = tb_switch_tmu_init(sw);
  		if (ret)
  			return ret;
  	}
  
  	ret = device_add(&sw->dev);
  	if (ret) {
  		dev_err(&sw->dev, "failed to add device: %d\n", ret);
  		return ret;
  	}
  
  	if (tb_route(sw)) {
  		dev_info(&sw->dev, "new device found, vendor=%#x device=%#x\n",
  			 sw->vendor, sw->device);
  		if (sw->vendor_name && sw->device_name)
  			dev_info(&sw->dev, "%s %s\n", sw->vendor_name,
  				 sw->device_name);
  	}
  
  	ret = tb_switch_nvm_add(sw);
  	if (ret) {
  		dev_err(&sw->dev, "failed to add NVM devices\n");
  		device_del(&sw->dev);
  		return ret;
  	}
  
  	/*
  	 * Thunderbolt routers do not generate wakeups themselves but
  	 * they forward wakeups from tunneled protocols, so enable it
  	 * here.
  	 */
  	device_init_wakeup(&sw->dev, true);
  
  	pm_runtime_set_active(&sw->dev);
  	if (sw->rpm) {
  		pm_runtime_set_autosuspend_delay(&sw->dev, TB_AUTOSUSPEND_DELAY);
  		pm_runtime_use_autosuspend(&sw->dev);
  		pm_runtime_mark_last_busy(&sw->dev);
  		pm_runtime_enable(&sw->dev);
  		pm_request_autosuspend(&sw->dev);
  	}
  
  	tb_switch_debugfs_init(sw);
  	return 0;
  }
  
  /**
   * tb_switch_remove() - Remove and release a switch
   * @sw: Switch to remove
   *
   * This will remove the switch from the domain and release it after last
   * reference count drops to zero. If there are switches connected below
   * this switch, they will be removed as well.
   */
  void tb_switch_remove(struct tb_switch *sw)
  {
  	struct tb_port *port;
  
  	tb_switch_debugfs_remove(sw);
  
  	if (sw->rpm) {
  		pm_runtime_get_sync(&sw->dev);
  		pm_runtime_disable(&sw->dev);
  	}
  
  	/* port 0 is the switch itself and never has a remote */
  	tb_switch_for_each_port(sw, port) {
  		if (tb_port_has_remote(port)) {
  			tb_switch_remove(port->remote->sw);
  			port->remote = NULL;
  		} else if (port->xdomain) {
  			tb_xdomain_remove(port->xdomain);
  			port->xdomain = NULL;
  		}
  
  		/* Remove any downstream retimers */
  		tb_retimer_remove_all(port);
  	}
  
  	if (!sw->is_unplugged)
  		tb_plug_events_active(sw, false);
  
  	tb_switch_nvm_remove(sw);
  
  	if (tb_route(sw))
  		dev_info(&sw->dev, "device disconnected\n");
  	device_unregister(&sw->dev);
  }
  
  /**
   * tb_sw_set_unplugged() - set is_unplugged on switch and downstream switches
   * @sw: Router to mark unplugged
   */
  void tb_sw_set_unplugged(struct tb_switch *sw)
  {
  	struct tb_port *port;
  
  	if (sw == sw->tb->root_switch) {
  		tb_sw_WARN(sw, "cannot unplug root switch\n");
  		return;
  	}
  	if (sw->is_unplugged) {
  		tb_sw_WARN(sw, "is_unplugged already set\n");
  		return;
  	}
  	sw->is_unplugged = true;
  	tb_switch_for_each_port(sw, port) {
  		if (tb_port_has_remote(port))
  			tb_sw_set_unplugged(port->remote->sw);
  		else if (port->xdomain)
  			port->xdomain->is_unplugged = true;
  	}
  }
  
  static int tb_switch_set_wake(struct tb_switch *sw, unsigned int flags)
  {
  	if (flags)
  		tb_sw_dbg(sw, "enabling wakeup: %#x\n", flags);
  	else
  		tb_sw_dbg(sw, "disabling wakeup\n");
  
  	if (tb_switch_is_usb4(sw))
  		return usb4_switch_set_wake(sw, flags);
  	return tb_lc_set_wake(sw, flags);
  }
  
  int tb_switch_resume(struct tb_switch *sw)
  {
  	struct tb_port *port;
  	int err;
  
  	tb_sw_dbg(sw, "resuming switch\n");
  
  	/*
  	 * Check for UID of the connected switches except for root
  	 * switch which we assume cannot be removed.
  	 */
  	if (tb_route(sw)) {
  		u64 uid;
  
  		/*
  		 * Check first that we can still read the switch config
  		 * space. It may be that there is now another domain
  		 * connected.
  		 */
  		err = tb_cfg_get_upstream_port(sw->tb->ctl, tb_route(sw));
  		if (err < 0) {
  			tb_sw_info(sw, "switch not present anymore\n");
  			return err;
  		}
  
  		if (tb_switch_is_usb4(sw))
  			err = usb4_switch_read_uid(sw, &uid);
  		else
  			err = tb_drom_read_uid_only(sw, &uid);
  		if (err) {
  			tb_sw_warn(sw, "uid read failed\n");
  			return err;
  		}
  		if (sw->uid != uid) {
  			tb_sw_info(sw,
  				"changed while suspended (uid %#llx -> %#llx)\n",
  				sw->uid, uid);
  			return -ENODEV;
  		}
  	}
  
  	err = tb_switch_configure(sw);
  	if (err)
  		return err;
  
  	/* Disable wakes */
  	tb_switch_set_wake(sw, 0);
  
  	err = tb_switch_tmu_init(sw);
  	if (err)
  		return err;
  
  	/* check for surviving downstream switches */
  	tb_switch_for_each_port(sw, port) {
  		if (!tb_port_has_remote(port) && !port->xdomain) {
  			/*
  			 * For disconnected downstream lane adapters
  			 * start lane initialization now so we detect
  			 * future connects.
  			 */
  			if (!tb_is_upstream_port(port) && tb_port_is_null(port))
  				tb_port_start_lane_initialization(port);
  			continue;
  		} else if (port->xdomain) {
  			/*
  			 * Start lane initialization for XDomain so the
  			 * link gets re-established.
  			 */
  			tb_port_start_lane_initialization(port);
  		}
  
  		if (tb_wait_for_port(port, true) <= 0) {
  			tb_port_warn(port,
  				     "lost during suspend, disconnecting\n");
  			if (tb_port_has_remote(port))
  				tb_sw_set_unplugged(port->remote->sw);
  			else if (port->xdomain)
  				port->xdomain->is_unplugged = true;
  		} else if (tb_port_has_remote(port) || port->xdomain) {
  			/*
  			 * Always unlock the port so the downstream
  			 * switch/domain is accessible.
  			 */
  			if (tb_port_unlock(port))
  				tb_port_warn(port, "failed to unlock port\n");
  			if (port->remote && tb_switch_resume(port->remote->sw)) {
  				tb_port_warn(port,
  					     "lost during suspend, disconnecting\n");
  				tb_sw_set_unplugged(port->remote->sw);
  			}
  		}
  	}
  	return 0;
  }
  
  /**
   * tb_switch_suspend() - Put a switch to sleep
   * @sw: Switch to suspend
   * @runtime: Is this runtime suspend or system sleep
   *
   * Suspends router and all its children. Enables wakes according to
   * value of @runtime and then sets sleep bit for the router. If @sw is
   * host router the domain is ready to go to sleep once this function
   * returns.
   */
  void tb_switch_suspend(struct tb_switch *sw, bool runtime)
  {
  	unsigned int flags = 0;
  	struct tb_port *port;
  	int err;
  
  	tb_sw_dbg(sw, "suspending switch\n");
  
  	err = tb_plug_events_active(sw, false);
  	if (err)
  		return;
  
  	tb_switch_for_each_port(sw, port) {
  		if (tb_port_has_remote(port))
  			tb_switch_suspend(port->remote->sw, runtime);
  	}
  
  	if (runtime) {
  		/* Trigger wake when something is plugged in/out */
  		flags |= TB_WAKE_ON_CONNECT | TB_WAKE_ON_DISCONNECT;
  		flags |= TB_WAKE_ON_USB4 | TB_WAKE_ON_USB3 | TB_WAKE_ON_PCIE;
  	} else if (device_may_wakeup(&sw->dev)) {
  		flags |= TB_WAKE_ON_USB4 | TB_WAKE_ON_USB3 | TB_WAKE_ON_PCIE;
  	}
  
  	tb_switch_set_wake(sw, flags);
  
  	if (tb_switch_is_usb4(sw))
  		usb4_switch_set_sleep(sw);
  	else
  		tb_lc_set_sleep(sw);
  }
  
  /**
   * tb_switch_query_dp_resource() - Query availability of DP resource
   * @sw: Switch whose DP resource is queried
   * @in: DP IN port
   *
   * Queries availability of DP resource for DP tunneling using switch
   * specific means. Returns %true if resource is available.
   */
  bool tb_switch_query_dp_resource(struct tb_switch *sw, struct tb_port *in)
  {
  	if (tb_switch_is_usb4(sw))
  		return usb4_switch_query_dp_resource(sw, in);
  	return tb_lc_dp_sink_query(sw, in);
  }
  
  /**
   * tb_switch_alloc_dp_resource() - Allocate available DP resource
   * @sw: Switch whose DP resource is allocated
   * @in: DP IN port
   *
   * Allocates DP resource for DP tunneling. The resource must be
   * available for this to succeed (see tb_switch_query_dp_resource()).
   * Returns %0 in success and negative errno otherwise.
   */
  int tb_switch_alloc_dp_resource(struct tb_switch *sw, struct tb_port *in)
  {
  	if (tb_switch_is_usb4(sw))
  		return usb4_switch_alloc_dp_resource(sw, in);
  	return tb_lc_dp_sink_alloc(sw, in);
  }
  
  /**
   * tb_switch_dealloc_dp_resource() - De-allocate DP resource
   * @sw: Switch whose DP resource is de-allocated
   * @in: DP IN port
   *
   * De-allocates DP resource that was previously allocated for DP
   * tunneling.
   */
  void tb_switch_dealloc_dp_resource(struct tb_switch *sw, struct tb_port *in)
  {
  	int ret;
  
  	if (tb_switch_is_usb4(sw))
  		ret = usb4_switch_dealloc_dp_resource(sw, in);
  	else
  		ret = tb_lc_dp_sink_dealloc(sw, in);
  
  	if (ret)
  		tb_sw_warn(sw, "failed to de-allocate DP resource for port %d\n",
  			   in->port);
  }
  
  struct tb_sw_lookup {
  	struct tb *tb;
  	u8 link;
  	u8 depth;
  	const uuid_t *uuid;
  	u64 route;
  };
  
  static int tb_switch_match(struct device *dev, const void *data)
  {
  	struct tb_switch *sw = tb_to_switch(dev);
  	const struct tb_sw_lookup *lookup = data;
  
  	if (!sw)
  		return 0;
  	if (sw->tb != lookup->tb)
  		return 0;
  
  	if (lookup->uuid)
  		return !memcmp(sw->uuid, lookup->uuid, sizeof(*lookup->uuid));
  
  	if (lookup->route) {
  		return sw->config.route_lo == lower_32_bits(lookup->route) &&
  		       sw->config.route_hi == upper_32_bits(lookup->route);
  	}
  
  	/* Root switch is matched only by depth */
  	if (!lookup->depth)
  		return !sw->depth;
  
  	return sw->link == lookup->link && sw->depth == lookup->depth;
  }
  
  /**
   * tb_switch_find_by_link_depth() - Find switch by link and depth
   * @tb: Domain the switch belongs
   * @link: Link number the switch is connected
   * @depth: Depth of the switch in link
   *
   * Returned switch has reference count increased so the caller needs to
   * call tb_switch_put() when done with the switch.
   */
  struct tb_switch *tb_switch_find_by_link_depth(struct tb *tb, u8 link, u8 depth)
  {
  	struct tb_sw_lookup lookup;
  	struct device *dev;
  
  	memset(&lookup, 0, sizeof(lookup));
  	lookup.tb = tb;
  	lookup.link = link;
  	lookup.depth = depth;
  
  	dev = bus_find_device(&tb_bus_type, NULL, &lookup, tb_switch_match);
  	if (dev)
  		return tb_to_switch(dev);
  
  	return NULL;
  }
  
  /**
   * tb_switch_find_by_uuid() - Find switch by UUID
   * @tb: Domain the switch belongs
   * @uuid: UUID to look for
   *
   * Returned switch has reference count increased so the caller needs to
   * call tb_switch_put() when done with the switch.
   */
  struct tb_switch *tb_switch_find_by_uuid(struct tb *tb, const uuid_t *uuid)
  {
  	struct tb_sw_lookup lookup;
  	struct device *dev;
  
  	memset(&lookup, 0, sizeof(lookup));
  	lookup.tb = tb;
  	lookup.uuid = uuid;
  
  	dev = bus_find_device(&tb_bus_type, NULL, &lookup, tb_switch_match);
  	if (dev)
  		return tb_to_switch(dev);
  
  	return NULL;
  }
  
  /**
   * tb_switch_find_by_route() - Find switch by route string
   * @tb: Domain the switch belongs
   * @route: Route string to look for
   *
   * Returned switch has reference count increased so the caller needs to
   * call tb_switch_put() when done with the switch.
   */
  struct tb_switch *tb_switch_find_by_route(struct tb *tb, u64 route)
  {
  	struct tb_sw_lookup lookup;
  	struct device *dev;
  
  	if (!route)
  		return tb_switch_get(tb->root_switch);
  
  	memset(&lookup, 0, sizeof(lookup));
  	lookup.tb = tb;
  	lookup.route = route;
  
  	dev = bus_find_device(&tb_bus_type, NULL, &lookup, tb_switch_match);
  	if (dev)
  		return tb_to_switch(dev);
  
  	return NULL;
  }
  
  /**
   * tb_switch_find_port() - return the first port of @type on @sw or NULL
   * @sw: Switch to find the port from
   * @type: Port type to look for
   */
  struct tb_port *tb_switch_find_port(struct tb_switch *sw,
  				    enum tb_port_type type)
  {
  	struct tb_port *port;
  
  	tb_switch_for_each_port(sw, port) {
  		if (port->config.type == type)
  			return port;
  	}
  
  	return NULL;
  }
  