treewide: remove redundant IS_ERR() before error code check

[linux/fpc-iii.git] / drivers / thunderbolt / switch.c

// 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;
        }

        if (tb_switch_is_usb4(sw))
                return usb4_switch_nvm_write(sw, 0, buf, image_size);
        return dma_port_flash_write(sw->dma_port, 0, buf, image_size);
}

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 = pci_find_pcie_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 = pci_find_pcie_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_switch *sw = priv;
        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_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_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 (!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) {
                dev_info(&sw->dev,
                         "NVM format of vendor %#x is not known, disabling NVM upgrade\n",
                         sw->config.vendor_id);
                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 = nvm_read(sw, 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 = nvm_read(sw, 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 & 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_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, ADP_CS_5, 1);
        if (ret)
                return ret;

        data &= ~ADP_CS_5_LCA_MASK;
        data |= (credits << ADP_CS_5_LCA_SHIFT) & ADP_CS_5_LCA_MASK;

        return tb_port_write(port, &data, TB_CFG_PORT, ADP_CS_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_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;
}

/**
 * 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");

                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);

        /* Control port does not need HopID allocation */
        if (port->port) {
                ida_init(&port->in_hopids);
                ida_init(&port->out_hopids);
        }

        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;
        }

        /* 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;
}

static 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;
}

static 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 ret;

        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);
}

static 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;
}

static 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);
}

/**
 * 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);
}

/**
 * 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 (tb_switch_is_icm(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;

        /* Plug events are always enabled in USB4 */
        if (tb_switch_is_usb4(sw))
                return 0;

        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
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_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;
                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);

        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_generation.attr,
        &dev_attr_key.attr,
        &dev_attr_nvm_authenticate.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 = 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_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;
        }

        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);
        struct tb_port *port;

        dma_port_free(sw->dma_port);

        tb_switch_for_each_port(sw, port) {
                if (!port->disabled) {
                        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);
}

/*
 * 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:
                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;
        }

        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);
                if (ret)
                        return ret;

                ret = usb4_switch_configure_link(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;

                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)
{
        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:
                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) && !tb_switch_is_icm(sw))
                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_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_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);

                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;
        }

        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)
{
        struct tb_port *port;

        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;
                }
        }

        if (!sw->is_unplugged)
                tb_plug_events_active(sw, false);

        if (tb_switch_is_usb4(sw))
                usb4_switch_unconfigure_link(sw);
        else
                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)
{
        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;
        }
}

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;

        /* check for surviving downstream switches */
        tb_switch_for_each_port(sw, port) {
                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) || 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;
}

void tb_switch_suspend(struct tb_switch *sw)
{
        struct tb_port *port;
        int err;

        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);
        }

        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;
}

void tb_switch_exit(void)
{
        ida_destroy(&nvm_ida);
}