ASR_BASE

Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/drivers/thunderbolt/switch.c b/marvell/linux/drivers/thunderbolt/switch.c
new file mode 100644
index 0000000..e53932d
--- /dev/null
+++ b/marvell/linux/drivers/thunderbolt/switch.c
@@ -0,0 +1,2136 @@
+// 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 <linux/vmalloc.h>
+
+#include "tb.h"
+
+/* Switch NVM support */
+
+#define NVM_DEVID		0x05
+#define NVM_VERSION		0x08
+#define NVM_CSS			0x10
+#define NVM_FLASH_SIZE		0x45
+
+#define NVM_MIN_SIZE		SZ_32K
+#define NVM_MAX_SIZE		SZ_512K
+
+static DEFINE_IDA(nvm_ida);
+
+struct nvm_auth_status {
+	struct list_head list;
+	uuid_t uuid;
+	u32 status;
+};
+
+/*
+ * 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;
+	}
+
+	return dma_port_flash_write(sw->dma_port, 0, buf, image_size);
+}
+
+static int nvm_authenticate_host(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(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 int tb_switch_nvm_read(void *priv, unsigned int offset, void *val,
+			      size_t bytes)
+{
+	struct tb_switch *sw = priv;
+	int ret;
+
+	pm_runtime_get_sync(&sw->dev);
+
+	if (!mutex_trylock(&sw->tb->lock)) {
+		ret = restart_syscall();
+		goto out;
+	}
+
+	ret = dma_port_flash_read(sw->dma_port, 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_no_read(void *priv, unsigned int offset, void *val,
+				 size_t bytes)
+{
+	return -EPERM;
+}
+
+static int tb_switch_nvm_write(void *priv, unsigned int offset, void *val,
+			       size_t bytes)
+{
+	struct tb_switch *sw = priv;
+	int ret = 0;
+
+	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.
+	 */
+	if (!sw->nvm->buf) {
+		sw->nvm->buf = vmalloc(NVM_MAX_SIZE);
+		if (!sw->nvm->buf) {
+			ret = -ENOMEM;
+			goto unlock;
+		}
+	}
+
+	sw->nvm->buf_data_size = offset + bytes;
+	memcpy(sw->nvm->buf + offset, val, bytes);
+
+unlock:
+	mutex_unlock(&sw->tb->lock);
+
+	return ret;
+}
+
+static struct nvmem_device *register_nvmem(struct tb_switch *sw, int id,
+					   size_t size, bool active)
+{
+	struct nvmem_config config;
+
+	memset(&config, 0, sizeof(config));
+
+	if (active) {
+		config.name = "nvm_active";
+		config.reg_read = tb_switch_nvm_read;
+		config.read_only = true;
+	} else {
+		config.name = "nvm_non_active";
+		config.reg_read = tb_switch_nvm_no_read;
+		config.reg_write = tb_switch_nvm_write;
+		config.root_only = true;
+	}
+
+	config.id = id;
+	config.stride = 4;
+	config.word_size = 4;
+	config.size = size;
+	config.dev = &sw->dev;
+	config.owner = THIS_MODULE;
+	config.priv = sw;
+
+	return nvmem_register(&config);
+}
+
+static int tb_switch_nvm_add(struct tb_switch *sw)
+{
+	struct nvmem_device *nvm_dev;
+	struct tb_switch_nvm *nvm;
+	u32 val;
+	int ret;
+
+	if (!sw->dma_port)
+		return 0;
+
+	nvm = kzalloc(sizeof(*nvm), GFP_KERNEL);
+	if (!nvm)
+		return -ENOMEM;
+
+	nvm->id = ida_simple_get(&nvm_ida, 0, 0, GFP_KERNEL);
+
+	/*
+	 * 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 = dma_port_flash_read(sw->dma_port, NVM_FLASH_SIZE, &val,
+					  sizeof(val));
+		if (ret)
+			goto err_ida;
+
+		hdr_size = sw->generation < 3 ? SZ_8K : SZ_16K;
+		nvm_size = (SZ_1M << (val & 7)) / 8;
+		nvm_size = (nvm_size - hdr_size) / 2;
+
+		ret = dma_port_flash_read(sw->dma_port, NVM_VERSION, &val,
+					  sizeof(val));
+		if (ret)
+			goto err_ida;
+
+		nvm->major = val >> 16;
+		nvm->minor = val >> 8;
+
+		nvm_dev = register_nvmem(sw, nvm->id, nvm_size, true);
+		if (IS_ERR(nvm_dev)) {
+			ret = PTR_ERR(nvm_dev);
+			goto err_ida;
+		}
+		nvm->active = nvm_dev;
+	}
+
+	if (!sw->no_nvm_upgrade) {
+		nvm_dev = register_nvmem(sw, nvm->id, NVM_MAX_SIZE, false);
+		if (IS_ERR(nvm_dev)) {
+			ret = PTR_ERR(nvm_dev);
+			goto err_nvm_active;
+		}
+		nvm->non_active = nvm_dev;
+	}
+
+	sw->nvm = nvm;
+	return 0;
+
+err_nvm_active:
+	if (nvm->active)
+		nvmem_unregister(nvm->active);
+err_ida:
+	ida_simple_remove(&nvm_ida, nvm->id);
+	kfree(nvm);
+
+	return ret;
+}
+
+static void tb_switch_nvm_remove(struct tb_switch *sw)
+{
+	struct tb_switch_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);
+
+	if (nvm->non_active)
+		nvmem_unregister(nvm->non_active);
+	if (nvm->active)
+		nvmem_unregister(nvm->active);
+	ida_simple_remove(&nvm_ida, nvm->id);
+	vfree(nvm->buf);
+	kfree(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
+ *
+ * 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.
+ */
+static 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
+ *
+ * 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
+ *
+ * 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;
+
+	nfc_credits = port->config.nfc_credits & TB_PORT_NFC_CREDITS_MASK;
+	nfc_credits += credits;
+
+	tb_port_dbg(port, "adding %d NFC credits to %lu",
+		    credits, port->config.nfc_credits & TB_PORT_NFC_CREDITS_MASK);
+
+	port->config.nfc_credits &= ~TB_PORT_NFC_CREDITS_MASK;
+	port->config.nfc_credits |= nfc_credits;
+
+	return tb_port_write(port, &port->config.nfc_credits,
+			     TB_CFG_PORT, 4, 1);
+}
+
+/**
+ * tb_port_set_initial_credits() - Set initial port link credits allocated
+ * @port: Port to set the initial credits
+ * @credits: Number of credits to to allocate
+ *
+ * Set initial credits value to be used for ingress shared buffering.
+ */
+int tb_port_set_initial_credits(struct tb_port *port, u32 credits)
+{
+	u32 data;
+	int ret;
+
+	ret = tb_port_read(port, &data, TB_CFG_PORT, 5, 1);
+	if (ret)
+		return ret;
+
+	data &= ~TB_PORT_LCA_MASK;
+	data |= (credits << TB_PORT_LCA_SHIFT) & TB_PORT_LCA_MASK;
+
+	return tb_port_write(port, &data, TB_CFG_PORT, 5, 1);
+}
+
+/**
+ * tb_port_clear_counter() - clear a counter in TB_CFG_COUNTER
+ *
+ * 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_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);
+			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");
+	} 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);
+
+	/* Control port does not need HopID allocation */
+	if (port->port) {
+		ida_init(&port->in_hopids);
+		ida_init(&port->out_hopids);
+	}
+
+	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;
+	}
+
+	/* HopIDs 0-7 are reserved */
+	if (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);
+}
+
+/**
+ * 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 (start->sw->config.depth < end->sw->config.depth) {
+		if (prev->remote &&
+		    prev->remote->sw->config.depth > prev->sw->config.depth)
+			next = prev->remote;
+		else
+			next = tb_port_at(tb_route(end->sw), prev->sw);
+	} 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;
+}
+
+/**
+ * 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);
+
+	default:
+		return false;
+	}
+}
+
+/**
+ * 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, 1))
+		return false;
+
+	return !!(data & TB_PCI_EN);
+}
+
+/**
+ * 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 ? TB_PCI_EN : 0x0;
+	if (!port->cap_adap)
+		return -ENXIO;
+	return tb_port_write(port, &word, TB_CFG_PORT, port->cap_adap, 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 + 2, 1);
+	if (ret)
+		return ret;
+
+	return !!(data & TB_DP_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 + 3, 1);
+	if (ret)
+		return ret;
+
+	data |= TB_DP_HPDC;
+	return tb_port_write(port, &data, TB_CFG_PORT, port->cap_adap + 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,
+			   ARRAY_SIZE(data));
+	if (ret)
+		return ret;
+
+	data[0] &= ~TB_DP_VIDEO_HOPID_MASK;
+	data[1] &= ~(TB_DP_AUX_RX_HOPID_MASK | TB_DP_AUX_TX_HOPID_MASK);
+
+	data[0] |= (video << TB_DP_VIDEO_HOPID_SHIFT) & TB_DP_VIDEO_HOPID_MASK;
+	data[1] |= aux_tx & TB_DP_AUX_TX_HOPID_MASK;
+	data[1] |= (aux_rx << TB_DP_AUX_RX_HOPID_SHIFT) & TB_DP_AUX_RX_HOPID_MASK;
+
+	return tb_port_write(port, data, TB_CFG_PORT, port->cap_adap,
+			     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,
+			 ARRAY_SIZE(data)))
+		return false;
+
+	return !!(data[0] & (TB_DP_VIDEO_EN | TB_DP_AUX_EN));
+}
+
+/**
+ * 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,
+			   ARRAY_SIZE(data));
+	if (ret)
+		return ret;
+
+	if (enable)
+		data[0] |= TB_DP_VIDEO_EN | TB_DP_AUX_EN;
+	else
+		data[0] &= ~(TB_DP_VIDEO_EN | TB_DP_AUX_EN);
+
+	return tb_port_write(port, data, TB_CFG_PORT, port->cap_adap,
+			     ARRAY_SIZE(data));
+}
+
+/* switch utility functions */
+
+static void tb_dump_switch(struct tb *tb, struct tb_regs_switch_header *sw)
+{
+	tb_dbg(tb, " Switch: %x:%x (Revision: %d, TB Version: %d)\n",
+	       sw->vendor_id, sw->device_id, sw->revision,
+	       sw->thunderbolt_version);
+	tb_dbg(tb, "  Max Port Number: %d\n", sw->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",
+	       sw->upstream_port_number, sw->depth,
+	       (((u64) sw->route_hi) << 32) | sw->route_lo,
+	       sw->enabled, sw->plug_events_delay);
+	tb_dbg(tb, "   unknown1: %#x unknown4: %#x\n",
+	       sw->__unknown1, sw->__unknown4);
+}
+
+/**
+ * reset_switch() - reconfigure route, enable and send TB_CFG_PKG_RESET
+ *
+ * Return: Returns 0 on success or an error code on failure.
+ */
+int tb_switch_reset(struct tb *tb, u64 route)
+{
+	struct tb_cfg_result res;
+	struct tb_regs_switch_header header = {
+		header.route_hi = route >> 32,
+		header.route_lo = route,
+		header.enabled = true,
+	};
+	tb_dbg(tb, "resetting switch at %llx\n", route);
+	res.err = tb_cfg_write(tb->ctl, ((u32 *) &header) + 2, route,
+			0, 2, 2, 2);
+	if (res.err)
+		return res.err;
+	res = tb_cfg_reset(tb->ctl, route, TB_CFG_DEFAULT_TIMEOUT);
+	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 (!sw->config.enabled)
+		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 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)
+		goto unlock;
+
+	switch (val) {
+	/* 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 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 void nvm_authenticate_start(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 = pci_find_pcie_root_port(sw->tb->nhi->pdev);
+	if (root_port)
+		pm_runtime_get_noresume(&root_port->dev);
+}
+
+static void nvm_authenticate_complete(struct tb_switch *sw)
+{
+	struct pci_dev *root_port;
+
+	root_port = pci_find_pcie_root_port(sw->tb->nhi->pdev);
+	if (root_port)
+		pm_runtime_put(&root_port->dev);
+}
+
+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_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct tb_switch *sw = tb_to_switch(dev);
+	bool 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 = kstrtobool(buf, &val);
+	if (ret)
+		goto exit_unlock;
+
+	/* Always clear the authentication status */
+	nvm_clear_auth_status(sw);
+
+	if (val) {
+		if (!sw->nvm->buf) {
+			ret = -EINVAL;
+			goto exit_unlock;
+		}
+
+		ret = nvm_validate_and_write(sw);
+		if (ret)
+			goto exit_unlock;
+
+		sw->nvm->authenticating = true;
+
+		if (!tb_route(sw)) {
+			/*
+			 * Keep root port from suspending as long as the
+			 * NVM upgrade process is running.
+			 */
+			nvm_authenticate_start(sw);
+			ret = nvm_authenticate_host(sw);
+		} else {
+			ret = nvm_authenticate_device(sw);
+		}
+	}
+
+exit_unlock:
+	mutex_unlock(&sw->tb->lock);
+exit_rpm:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
+
+	if (ret)
+		return ret;
+	return count;
+}
+static DEVICE_ATTR_RW(nvm_authenticate);
+
+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_key.attr,
+	&dev_attr_nvm_authenticate.attr,
+	&dev_attr_nvm_version.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 = container_of(kobj, struct device, kobj);
+	struct tb_switch *sw = tb_to_switch(dev);
+
+	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_nvm_authenticate.attr) {
+		if (sw->dma_port && !sw->no_nvm_upgrade)
+			return attr->mode;
+		return 0;
+	} else if (attr == &dev_attr_nvm_version.attr) {
+		if (sw->dma_port)
+			return attr->mode;
+		return 0;
+	} else if (attr == &dev_attr_boot.attr) {
+		if (tb_route(sw))
+			return attr->mode;
+		return 0;
+	}
+
+	return sw->safe_mode ? 0 : attr->mode;
+}
+
+static 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);
+	int i;
+
+	dma_port_free(sw->dma_port);
+
+	for (i = 1; i <= sw->config.max_port_number; i++) {
+		if (!sw->ports[i].disabled) {
+			ida_destroy(&sw->ports[i].in_hopids);
+			ida_destroy(&sw->ports[i].out_hopids);
+		}
+	}
+
+	kfree(sw->uuid);
+	kfree(sw->device_name);
+	kfree(sw->vendor_name);
+	kfree(sw->ports);
+	kfree(sw->drom);
+	kfree(sw->key);
+	kfree(sw);
+}
+
+/*
+ * 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,
+	.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:
+		/*
+		 * 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;
+	}
+}
+
+/**
+ * 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;
+
+	/* Make sure we do not exceed maximum topology limit */
+	depth = tb_route_length(route);
+	if (depth > TB_SWITCH_MAX_DEPTH)
+		return ERR_PTR(-EADDRNOTAVAIL);
+
+	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;
+
+	tb_dbg(tb, "current switch config:\n");
+	tb_dump_switch(tb, &sw->config);
+
+	/* 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;
+
+	/* 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;
+	}
+
+	sw->generation = tb_switch_get_generation(sw);
+
+	ret = tb_switch_find_vse_cap(sw, TB_VSE_CAP_PLUG_EVENTS);
+	if (ret < 0) {
+		tb_sw_warn(sw, "cannot find TB_VSE_CAP_PLUG_EVENTS aborting\n");
+		goto err_free_sw_ports;
+	}
+	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.
+ *
+ * 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, "initializing Switch at %#llx (depth: %d, up port: %d)\n",
+	       route, tb_route_length(route), sw->config.upstream_port_number);
+
+	if (sw->config.vendor_id != PCI_VENDOR_ID_INTEL)
+		tb_sw_warn(sw, "unknown switch vendor id %#x\n",
+			   sw->config.vendor_id);
+
+	sw->config.enabled = 1;
+
+	/* upload configuration */
+	ret = tb_sw_write(sw, 1 + (u32 *)&sw->config, TB_CFG_SWITCH, 1, 3);
+	if (ret)
+		return ret;
+
+	ret = tb_lc_configure_link(sw);
+	if (ret)
+		return ret;
+
+	return tb_plug_events_active(sw, true);
+}
+
+static int tb_switch_set_uuid(struct tb_switch *sw)
+{
+	u32 uuid[4];
+	int ret;
+
+	if (sw->uuid)
+		return 0;
+
+	/*
+	 * The newer controllers include fused UUID as part of link
+	 * controller specific registers
+	 */
+	ret = tb_lc_read_uuid(sw, uuid);
+	if (ret) {
+		/*
+		 * 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:
+		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;
+	}
+
+	/* Root switch DMA port requires running firmware */
+	if (!tb_route(sw) && sw->config.enabled)
+		return 0;
+
+	sw->dma_port = dma_port_alloc(sw);
+	if (!sw->dma_port)
+		return 0;
+
+	if (sw->no_nvm_upgrade)
+		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(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(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;
+}
+
+/**
+ * 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)
+		return ret;
+
+	if (!sw->safe_mode) {
+		/* read drom */
+		ret = tb_drom_read(sw);
+		if (ret) {
+			tb_sw_warn(sw, "tb_eeprom_read_rom failed\n");
+			return ret;
+		}
+		tb_sw_dbg(sw, "uid: %#llx\n", sw->uid);
+
+		ret = tb_switch_set_uuid(sw);
+		if (ret)
+			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)
+				return ret;
+		}
+	}
+
+	ret = device_add(&sw->dev);
+	if (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) {
+		device_del(&sw->dev);
+		return ret;
+	}
+
+	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);
+	}
+
+	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)
+{
+	int i;
+
+	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 */
+	for (i = 1; i <= sw->config.max_port_number; i++) {
+		if (tb_port_has_remote(&sw->ports[i])) {
+			tb_switch_remove(sw->ports[i].remote->sw);
+			sw->ports[i].remote = NULL;
+		} else if (sw->ports[i].xdomain) {
+			tb_xdomain_remove(sw->ports[i].xdomain);
+			sw->ports[i].xdomain = NULL;
+		}
+	}
+
+	if (!sw->is_unplugged)
+		tb_plug_events_active(sw, false);
+	tb_lc_unconfigure_link(sw);
+
+	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
+ */
+void tb_sw_set_unplugged(struct tb_switch *sw)
+{
+	int i;
+	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;
+	for (i = 0; i <= sw->config.max_port_number; i++) {
+		if (tb_port_has_remote(&sw->ports[i]))
+			tb_sw_set_unplugged(sw->ports[i].remote->sw);
+		else if (sw->ports[i].xdomain)
+			sw->ports[i].xdomain->is_unplugged = true;
+	}
+}
+
+int tb_switch_resume(struct tb_switch *sw)
+{
+	int i, 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;
+		}
+
+		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;
+		}
+	}
+
+	/* upload configuration */
+	err = tb_sw_write(sw, 1 + (u32 *) &sw->config, TB_CFG_SWITCH, 1, 3);
+	if (err)
+		return err;
+
+	err = tb_lc_configure_link(sw);
+	if (err)
+		return err;
+
+	err = tb_plug_events_active(sw, true);
+	if (err)
+		return err;
+
+	/* check for surviving downstream switches */
+	for (i = 1; i <= sw->config.max_port_number; i++) {
+		struct tb_port *port = &sw->ports[i];
+
+		if (!tb_port_has_remote(port) && !port->xdomain)
+			continue;
+
+		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)) {
+			if (tb_switch_resume(port->remote->sw)) {
+				tb_port_warn(port,
+					     "lost during suspend, disconnecting\n");
+				tb_sw_set_unplugged(port->remote->sw);
+			}
+		}
+	}
+	return 0;
+}
+
+void tb_switch_suspend(struct tb_switch *sw)
+{
+	int i, err;
+	err = tb_plug_events_active(sw, false);
+	if (err)
+		return;
+
+	for (i = 1; i <= sw->config.max_port_number; i++) {
+		if (tb_port_has_remote(&sw->ports[i]))
+			tb_switch_suspend(sw->ports[i].remote->sw);
+	}
+
+	tb_lc_set_sleep(sw);
+}
+
+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;
+}
+
+void tb_switch_exit(void)
+{
+	ida_destroy(&nvm_ida);
+}