// SPDX-License-Identifier: GPL-2.0
/*
 * Thunderbolt XDomain discovery protocol support
 *
 * Copyright (C) 2017, Intel Corporation
 * Authors: Michael Jamet <michael.jamet@intel.com>
 *          Mika Westerberg <mika.westerberg@linux.intel.com>
 */

#include <linux/device.h>
#include <linux/kmod.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/utsname.h>
#include <linux/uuid.h>
#include <linux/workqueue.h>

#include "tb.h"

#define XDOMAIN_DEFAULT_TIMEOUT                 5000 /* ms */
#define XDOMAIN_PROPERTIES_RETRIES              60
#define XDOMAIN_PROPERTIES_CHANGED_RETRIES      10

struct xdomain_request_work {
        struct work_struct work;
        struct tb_xdp_header *pkg;
        struct tb *tb;
};

/* Serializes access to the properties and protocol handlers below */
static DEFINE_MUTEX(xdomain_lock);

/* Properties exposed to the remote domains */
static struct tb_property_dir *xdomain_property_dir;
static u32 *xdomain_property_block;
static u32 xdomain_property_block_len;
static u32 xdomain_property_block_gen;

/* Additional protocol handlers */
static LIST_HEAD(protocol_handlers);

/* UUID for XDomain discovery protocol: b638d70e-42ff-40bb-97c2-90e2c0b2ff07 */
static const uuid_t tb_xdp_uuid =
        UUID_INIT(0xb638d70e, 0x42ff, 0x40bb,
                  0x97, 0xc2, 0x90, 0xe2, 0xc0, 0xb2, 0xff, 0x07);

static bool tb_xdomain_match(const struct tb_cfg_request *req,
                             const struct ctl_pkg *pkg)
{
        switch (pkg->frame.eof) {
        case TB_CFG_PKG_ERROR:
                return true;

        case TB_CFG_PKG_XDOMAIN_RESP: {
                const struct tb_xdp_header *res_hdr = pkg->buffer;
                const struct tb_xdp_header *req_hdr = req->request;

                if (pkg->frame.size < req->response_size / 4)
                        return false;

                /* Make sure route matches */
                if ((res_hdr->xd_hdr.route_hi & ~BIT(31)) !=
                     req_hdr->xd_hdr.route_hi)
                        return false;
                if ((res_hdr->xd_hdr.route_lo) != req_hdr->xd_hdr.route_lo)
                        return false;

                /* Check that the XDomain protocol matches */
                if (!uuid_equal(&res_hdr->uuid, &req_hdr->uuid))
                        return false;

                return true;
        }

        default:
                return false;
        }
}

static bool tb_xdomain_copy(struct tb_cfg_request *req,
                            const struct ctl_pkg *pkg)
{
        memcpy(req->response, pkg->buffer, req->response_size);
        req->result.err = 0;
        return true;
}

static void response_ready(void *data)
{
        tb_cfg_request_put(data);
}

static int __tb_xdomain_response(struct tb_ctl *ctl, const void *response,
                                 size_t size, enum tb_cfg_pkg_type type)
{
        struct tb_cfg_request *req;

        req = tb_cfg_request_alloc();
        if (!req)
                return -ENOMEM;

        req->match = tb_xdomain_match;
        req->copy = tb_xdomain_copy;
        req->request = response;
        req->request_size = size;
        req->request_type = type;

        return tb_cfg_request(ctl, req, response_ready, req);
}

/**
 * tb_xdomain_response() - Send a XDomain response message
 * @xd: XDomain to send the message
 * @response: Response to send
 * @size: Size of the response
 * @type: PDF type of the response
 *
 * This can be used to send a XDomain response message to the other
 * domain. No response for the message is expected.
 *
 * Return: %0 in case of success and negative errno in case of failure
 */
int tb_xdomain_response(struct tb_xdomain *xd, const void *response,
                        size_t size, enum tb_cfg_pkg_type type)
{
        return __tb_xdomain_response(xd->tb->ctl, response, size, type);
}
EXPORT_SYMBOL_GPL(tb_xdomain_response);

static int __tb_xdomain_request(struct tb_ctl *ctl, const void *request,
        size_t request_size, enum tb_cfg_pkg_type request_type, void *response,
        size_t response_size, enum tb_cfg_pkg_type response_type,
        unsigned int timeout_msec)
{
        struct tb_cfg_request *req;
        struct tb_cfg_result res;

        req = tb_cfg_request_alloc();
        if (!req)
                return -ENOMEM;

        req->match = tb_xdomain_match;
        req->copy = tb_xdomain_copy;
        req->request = request;
        req->request_size = request_size;
        req->request_type = request_type;
        req->response = response;
        req->response_size = response_size;
        req->response_type = response_type;

        res = tb_cfg_request_sync(ctl, req, timeout_msec);

        tb_cfg_request_put(req);

        return res.err == 1 ? -EIO : res.err;
}

/**
 * tb_xdomain_request() - Send a XDomain request
 * @xd: XDomain to send the request
 * @request: Request to send
 * @request_size: Size of the request in bytes
 * @request_type: PDF type of the request
 * @response: Response is copied here
 * @response_size: Expected size of the response in bytes
 * @response_type: Expected PDF type of the response
 * @timeout_msec: Timeout in milliseconds to wait for the response
 *
 * This function can be used to send XDomain control channel messages to
 * the other domain. The function waits until the response is received
 * or when timeout triggers. Whichever comes first.
 *
 * Return: %0 in case of success and negative errno in case of failure
 */
int tb_xdomain_request(struct tb_xdomain *xd, const void *request,
        size_t request_size, enum tb_cfg_pkg_type request_type,
        void *response, size_t response_size,
        enum tb_cfg_pkg_type response_type, unsigned int timeout_msec)
{
        return __tb_xdomain_request(xd->tb->ctl, request, request_size,
                                    request_type, response, response_size,
                                    response_type, timeout_msec);
}
EXPORT_SYMBOL_GPL(tb_xdomain_request);

static inline void tb_xdp_fill_header(struct tb_xdp_header *hdr, u64 route,
        u8 sequence, enum tb_xdp_type type, size_t size)
{
        u32 length_sn;

        length_sn = (size - sizeof(hdr->xd_hdr)) / 4;
        length_sn |= (sequence << TB_XDOMAIN_SN_SHIFT) & TB_XDOMAIN_SN_MASK;

        hdr->xd_hdr.route_hi = upper_32_bits(route);
        hdr->xd_hdr.route_lo = lower_32_bits(route);
        hdr->xd_hdr.length_sn = length_sn;
        hdr->type = type;
        memcpy(&hdr->uuid, &tb_xdp_uuid, sizeof(tb_xdp_uuid));
}

static int tb_xdp_handle_error(const struct tb_xdp_header *hdr)
{
        const struct tb_xdp_error_response *error;

        if (hdr->type != ERROR_RESPONSE)
                return 0;

        error = (const struct tb_xdp_error_response *)hdr;

        switch (error->error) {
        case ERROR_UNKNOWN_PACKET:
        case ERROR_UNKNOWN_DOMAIN:
                return -EIO;
        case ERROR_NOT_SUPPORTED:
                return -ENOTSUPP;
        case ERROR_NOT_READY:
                return -EAGAIN;
        default:
                break;
        }

        return 0;
}

static int tb_xdp_error_response(struct tb_ctl *ctl, u64 route, u8 sequence,
                                 enum tb_xdp_error error)
{
        struct tb_xdp_error_response res;

        memset(&res, 0, sizeof(res));
        tb_xdp_fill_header(&res.hdr, route, sequence, ERROR_RESPONSE,
                           sizeof(res));
        res.error = error;

        return __tb_xdomain_response(ctl, &res, sizeof(res),
                                     TB_CFG_PKG_XDOMAIN_RESP);
}

static int tb_xdp_properties_request(struct tb_ctl *ctl, u64 route,
        const uuid_t *src_uuid, const uuid_t *dst_uuid, int retry,
        u32 **block, u32 *generation)
{
        struct tb_xdp_properties_response *res;
        struct tb_xdp_properties req;
        u16 data_len, len;
        size_t total_size;
        u32 *data = NULL;
        int ret;

        total_size = sizeof(*res) + TB_XDP_PROPERTIES_MAX_DATA_LENGTH * 4;
        res = kzalloc(total_size, GFP_KERNEL);
        if (!res)
                return -ENOMEM;

        memset(&req, 0, sizeof(req));
        tb_xdp_fill_header(&req.hdr, route, retry % 4, PROPERTIES_REQUEST,
                           sizeof(req));
        memcpy(&req.src_uuid, src_uuid, sizeof(*src_uuid));
        memcpy(&req.dst_uuid, dst_uuid, sizeof(*dst_uuid));

        len = 0;
        data_len = 0;

        do {
                ret = __tb_xdomain_request(ctl, &req, sizeof(req),
                                           TB_CFG_PKG_XDOMAIN_REQ, res,
                                           total_size, TB_CFG_PKG_XDOMAIN_RESP,
                                           XDOMAIN_DEFAULT_TIMEOUT);
                if (ret)
                        goto err;

                ret = tb_xdp_handle_error(&res->hdr);
                if (ret)
                        goto err;

                /*
                 * Package length includes the whole payload without the
                 * XDomain header. Validate first that the package is at
                 * least size of the response structure.
                 */
                len = res->hdr.xd_hdr.length_sn & TB_XDOMAIN_LENGTH_MASK;
                if (len < sizeof(*res) / 4) {
                        ret = -EINVAL;
                        goto err;
                }

                len += sizeof(res->hdr.xd_hdr) / 4;
                len -= sizeof(*res) / 4;

                if (res->offset != req.offset) {
                        ret = -EINVAL;
                        goto err;
                }

                /*
                 * First time allocate block that has enough space for
                 * the whole properties block.
                 */
                if (!data) {
                        data_len = res->data_length;
                        if (data_len > TB_XDP_PROPERTIES_MAX_LENGTH) {
                                ret = -E2BIG;
                                goto err;
                        }

                        data = kcalloc(data_len, sizeof(u32), GFP_KERNEL);
                        if (!data) {
                                ret = -ENOMEM;
                                goto err;
                        }
                }

                memcpy(data + req.offset, res->data, len * 4);
                req.offset += len;
        } while (!data_len || req.offset < data_len);

        *block = data;
        *generation = res->generation;

        kfree(res);

        return data_len;

err:
        kfree(data);
        kfree(res);

        return ret;
}

static int tb_xdp_properties_response(struct tb *tb, struct tb_ctl *ctl,
        u64 route, u8 sequence, const uuid_t *src_uuid,
        const struct tb_xdp_properties *req)
{
        struct tb_xdp_properties_response *res;
        size_t total_size;
        u16 len;
        int ret;

        /*
         * Currently we expect all requests to be directed to us. The
         * protocol supports forwarding, though which we might add
         * support later on.
         */
        if (!uuid_equal(src_uuid, &req->dst_uuid)) {
                tb_xdp_error_response(ctl, route, sequence,
                                      ERROR_UNKNOWN_DOMAIN);
                return 0;
        }

        mutex_lock(&xdomain_lock);

        if (req->offset >= xdomain_property_block_len) {
                mutex_unlock(&xdomain_lock);
                return -EINVAL;
        }

        len = xdomain_property_block_len - req->offset;
        len = min_t(u16, len, TB_XDP_PROPERTIES_MAX_DATA_LENGTH);
        total_size = sizeof(*res) + len * 4;

        res = kzalloc(total_size, GFP_KERNEL);
        if (!res) {
                mutex_unlock(&xdomain_lock);
                return -ENOMEM;
        }

        tb_xdp_fill_header(&res->hdr, route, sequence, PROPERTIES_RESPONSE,
                           total_size);
        res->generation = xdomain_property_block_gen;
        res->data_length = xdomain_property_block_len;
        res->offset = req->offset;
        uuid_copy(&res->src_uuid, src_uuid);
        uuid_copy(&res->dst_uuid, &req->src_uuid);
        memcpy(res->data, &xdomain_property_block[req->offset], len * 4);

        mutex_unlock(&xdomain_lock);

        ret = __tb_xdomain_response(ctl, res, total_size,
                                    TB_CFG_PKG_XDOMAIN_RESP);

        kfree(res);
        return ret;
}

static int tb_xdp_properties_changed_request(struct tb_ctl *ctl, u64 route,
                                             int retry, const uuid_t *uuid)
{
        struct tb_xdp_properties_changed_response res;
        struct tb_xdp_properties_changed req;
        int ret;

        memset(&req, 0, sizeof(req));
        tb_xdp_fill_header(&req.hdr, route, retry % 4,
                           PROPERTIES_CHANGED_REQUEST, sizeof(req));
        uuid_copy(&req.src_uuid, uuid);

        memset(&res, 0, sizeof(res));
        ret = __tb_xdomain_request(ctl, &req, sizeof(req),
                                   TB_CFG_PKG_XDOMAIN_REQ, &res, sizeof(res),
                                   TB_CFG_PKG_XDOMAIN_RESP,
                                   XDOMAIN_DEFAULT_TIMEOUT);
        if (ret)
                return ret;

        return tb_xdp_handle_error(&res.hdr);
}

static int
tb_xdp_properties_changed_response(struct tb_ctl *ctl, u64 route, u8 sequence)
{
        struct tb_xdp_properties_changed_response res;

        memset(&res, 0, sizeof(res));
        tb_xdp_fill_header(&res.hdr, route, sequence,
                           PROPERTIES_CHANGED_RESPONSE, sizeof(res));
        return __tb_xdomain_response(ctl, &res, sizeof(res),
                                     TB_CFG_PKG_XDOMAIN_RESP);
}

/**
 * tb_register_protocol_handler() - Register protocol handler
 * @handler: Handler to register
 *
 * This allows XDomain service drivers to hook into incoming XDomain
 * messages. After this function is called the service driver needs to
 * be able to handle calls to callback whenever a package with the
 * registered protocol is received.
 */
int tb_register_protocol_handler(struct tb_protocol_handler *handler)
{
        if (!handler->uuid || !handler->callback)
                return -EINVAL;
        if (uuid_equal(handler->uuid, &tb_xdp_uuid))
                return -EINVAL;

        mutex_lock(&xdomain_lock);
        list_add_tail(&handler->list, &protocol_handlers);
        mutex_unlock(&xdomain_lock);

        return 0;
}
EXPORT_SYMBOL_GPL(tb_register_protocol_handler);

/**
 * tb_unregister_protocol_handler() - Unregister protocol handler
 * @handler: Handler to unregister
 *
 * Removes the previously registered protocol handler.
 */
void tb_unregister_protocol_handler(struct tb_protocol_handler *handler)
{
        mutex_lock(&xdomain_lock);
        list_del_init(&handler->list);
        mutex_unlock(&xdomain_lock);
}
EXPORT_SYMBOL_GPL(tb_unregister_protocol_handler);

static void tb_xdp_handle_request(struct work_struct *work)
{
        struct xdomain_request_work *xw = container_of(work, typeof(*xw), work);
        const struct tb_xdp_header *pkg = xw->pkg;
        const struct tb_xdomain_header *xhdr = &pkg->xd_hdr;
        struct tb *tb = xw->tb;
        struct tb_ctl *ctl = tb->ctl;
        const uuid_t *uuid;
        int ret = 0;
        u32 sequence;
        u64 route;

        route = ((u64)xhdr->route_hi << 32 | xhdr->route_lo) & ~BIT_ULL(63);
        sequence = xhdr->length_sn & TB_XDOMAIN_SN_MASK;
        sequence >>= TB_XDOMAIN_SN_SHIFT;

        mutex_lock(&tb->lock);
        if (tb->root_switch)
                uuid = tb->root_switch->uuid;
        else
                uuid = NULL;
        mutex_unlock(&tb->lock);

        if (!uuid) {
                tb_xdp_error_response(ctl, route, sequence, ERROR_NOT_READY);
                goto out;
        }

        switch (pkg->type) {
        case PROPERTIES_REQUEST:
                ret = tb_xdp_properties_response(tb, ctl, route, sequence, uuid,
                        (const struct tb_xdp_properties *)pkg);
                break;

        case PROPERTIES_CHANGED_REQUEST: {
                const struct tb_xdp_properties_changed *xchg =
                        (const struct tb_xdp_properties_changed *)pkg;
                struct tb_xdomain *xd;

                ret = tb_xdp_properties_changed_response(ctl, route, sequence);

                /*
                 * Since the properties have been changed, let's update
                 * the xdomain related to this connection as well in
                 * case there is a change in services it offers.
                 */
                xd = tb_xdomain_find_by_uuid_locked(tb, &xchg->src_uuid);
                if (xd) {
                        queue_delayed_work(tb->wq, &xd->get_properties_work,
                                           msecs_to_jiffies(50));
                        tb_xdomain_put(xd);
                }

                break;
        }

        default:
                break;
        }

        if (ret) {
                tb_warn(tb, "failed to send XDomain response for %#x\n",
                        pkg->type);
        }

out:
        kfree(xw->pkg);
        kfree(xw);
}

static void
tb_xdp_schedule_request(struct tb *tb, const struct tb_xdp_header *hdr,
                        size_t size)
{
        struct xdomain_request_work *xw;

        xw = kmalloc(sizeof(*xw), GFP_KERNEL);
        if (!xw)
                return;

        INIT_WORK(&xw->work, tb_xdp_handle_request);
        xw->pkg = kmemdup(hdr, size, GFP_KERNEL);
        xw->tb = tb;

        queue_work(tb->wq, &xw->work);
}

/**
 * tb_register_service_driver() - Register XDomain service driver
 * @drv: Driver to register
 *
 * Registers new service driver from @drv to the bus.
 */
int tb_register_service_driver(struct tb_service_driver *drv)
{
        drv->driver.bus = &tb_bus_type;
        return driver_register(&drv->driver);
}
EXPORT_SYMBOL_GPL(tb_register_service_driver);

/**
 * tb_unregister_service_driver() - Unregister XDomain service driver
 * @xdrv: Driver to unregister
 *
 * Unregisters XDomain service driver from the bus.
 */
void tb_unregister_service_driver(struct tb_service_driver *drv)
{
        driver_unregister(&drv->driver);
}
EXPORT_SYMBOL_GPL(tb_unregister_service_driver);

static ssize_t key_show(struct device *dev, struct device_attribute *attr,
                        char *buf)
{
        struct tb_service *svc = container_of(dev, struct tb_service, dev);

        /*
         * It should be null terminated but anything else is pretty much
         * allowed.
         */
        return sprintf(buf, "%*pEp\n", (int)strlen(svc->key), svc->key);
}
static DEVICE_ATTR_RO(key);

static int get_modalias(struct tb_service *svc, char *buf, size_t size)
{
        return snprintf(buf, size, "tbsvc:k%sp%08Xv%08Xr%08X", svc->key,
                        svc->prtcid, svc->prtcvers, svc->prtcrevs);
}

static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
                             char *buf)
{
        struct tb_service *svc = container_of(dev, struct tb_service, dev);

        /* Full buffer size except new line and null termination */
        get_modalias(svc, buf, PAGE_SIZE - 2);
        return sprintf(buf, "%s\n", buf);
}
static DEVICE_ATTR_RO(modalias);

static ssize_t prtcid_show(struct device *dev, struct device_attribute *attr,
                           char *buf)
{
        struct tb_service *svc = container_of(dev, struct tb_service, dev);

        return sprintf(buf, "%u\n", svc->prtcid);
}
static DEVICE_ATTR_RO(prtcid);

static ssize_t prtcvers_show(struct device *dev, struct device_attribute *attr,
                             char *buf)
{
        struct tb_service *svc = container_of(dev, struct tb_service, dev);

        return sprintf(buf, "%u\n", svc->prtcvers);
}
static DEVICE_ATTR_RO(prtcvers);

static ssize_t prtcrevs_show(struct device *dev, struct device_attribute *attr,
                             char *buf)
{
        struct tb_service *svc = container_of(dev, struct tb_service, dev);

        return sprintf(buf, "%u\n", svc->prtcrevs);
}
static DEVICE_ATTR_RO(prtcrevs);

static ssize_t prtcstns_show(struct device *dev, struct device_attribute *attr,
                             char *buf)
{
        struct tb_service *svc = container_of(dev, struct tb_service, dev);

        return sprintf(buf, "0x%08x\n", svc->prtcstns);
}
static DEVICE_ATTR_RO(prtcstns);

static struct attribute *tb_service_attrs[] = {
        &dev_attr_key.attr,
        &dev_attr_modalias.attr,
        &dev_attr_prtcid.attr,
        &dev_attr_prtcvers.attr,
        &dev_attr_prtcrevs.attr,
        &dev_attr_prtcstns.attr,
        NULL,
};

static struct attribute_group tb_service_attr_group = {
        .attrs = tb_service_attrs,
};

static const struct attribute_group *tb_service_attr_groups[] = {
        &tb_service_attr_group,
        NULL,
};

static int tb_service_uevent(struct device *dev, struct kobj_uevent_env *env)
{
        struct tb_service *svc = container_of(dev, struct tb_service, dev);
        char modalias[64];

        get_modalias(svc, modalias, sizeof(modalias));
        return add_uevent_var(env, "MODALIAS=%s", modalias);
}

static void tb_service_release(struct device *dev)
{
        struct tb_service *svc = container_of(dev, struct tb_service, dev);
        struct tb_xdomain *xd = tb_service_parent(svc);

        ida_simple_remove(&xd->service_ids, svc->id);
        kfree(svc->key);
        kfree(svc);
}

struct device_type tb_service_type = {
        .name = "thunderbolt_service",
        .groups = tb_service_attr_groups,
        .uevent = tb_service_uevent,
        .release = tb_service_release,
};
EXPORT_SYMBOL_GPL(tb_service_type);

static int remove_missing_service(struct device *dev, void *data)
{
        struct tb_xdomain *xd = data;
        struct tb_service *svc;

        svc = tb_to_service(dev);
        if (!svc)
                return 0;

        if (!tb_property_find(xd->properties, svc->key,
                              TB_PROPERTY_TYPE_DIRECTORY))
                device_unregister(dev);

        return 0;
}

static int find_service(struct device *dev, void *data)
{
        const struct tb_property *p = data;
        struct tb_service *svc;

        svc = tb_to_service(dev);
        if (!svc)
                return 0;

        return !strcmp(svc->key, p->key);
}

static int populate_service(struct tb_service *svc,
                            struct tb_property *property)
{
        struct tb_property_dir *dir = property->value.dir;
        struct tb_property *p;

        /* Fill in standard properties */
        p = tb_property_find(dir, "prtcid", TB_PROPERTY_TYPE_VALUE);
        if (p)
                svc->prtcid = p->value.immediate;
        p = tb_property_find(dir, "prtcvers", TB_PROPERTY_TYPE_VALUE);
        if (p)
                svc->prtcvers = p->value.immediate;
        p = tb_property_find(dir, "prtcrevs", TB_PROPERTY_TYPE_VALUE);
        if (p)
                svc->prtcrevs = p->value.immediate;
        p = tb_property_find(dir, "prtcstns", TB_PROPERTY_TYPE_VALUE);
        if (p)
                svc->prtcstns = p->value.immediate;

        svc->key = kstrdup(property->key, GFP_KERNEL);
        if (!svc->key)
                return -ENOMEM;

        return 0;
}

static void enumerate_services(struct tb_xdomain *xd)
{
        struct tb_service *svc;
        struct tb_property *p;
        struct device *dev;

        /*
         * First remove all services that are not available anymore in
         * the updated property block.
         */
        device_for_each_child_reverse(&xd->dev, xd, remove_missing_service);

        /* Then re-enumerate properties creating new services as we go */
        tb_property_for_each(xd->properties, p) {
                if (p->type != TB_PROPERTY_TYPE_DIRECTORY)
                        continue;

                /* If the service exists already we are fine */
                dev = device_find_child(&xd->dev, p, find_service);
                if (dev) {
                        put_device(dev);
                        continue;
                }

                svc = kzalloc(sizeof(*svc), GFP_KERNEL);
                if (!svc)
                        break;

                if (populate_service(svc, p)) {
                        kfree(svc);
                        break;
                }

                svc->id = ida_simple_get(&xd->service_ids, 0, 0, GFP_KERNEL);
                svc->dev.bus = &tb_bus_type;
                svc->dev.type = &tb_service_type;
                svc->dev.parent = &xd->dev;
                dev_set_name(&svc->dev, "%s.%d", dev_name(&xd->dev), svc->id);

                if (device_register(&svc->dev)) {
                        put_device(&svc->dev);
                        break;
                }
        }
}

static int populate_properties(struct tb_xdomain *xd,
                               struct tb_property_dir *dir)
{
        const struct tb_property *p;

        /* Required properties */
        p = tb_property_find(dir, "deviceid", TB_PROPERTY_TYPE_VALUE);
        if (!p)
                return -EINVAL;
        xd->device = p->value.immediate;

        p = tb_property_find(dir, "vendorid", TB_PROPERTY_TYPE_VALUE);
        if (!p)
                return -EINVAL;
        xd->vendor = p->value.immediate;

        kfree(xd->device_name);
        xd->device_name = NULL;
        kfree(xd->vendor_name);
        xd->vendor_name = NULL;

        /* Optional properties */
        p = tb_property_find(dir, "deviceid", TB_PROPERTY_TYPE_TEXT);
        if (p)
                xd->device_name = kstrdup(p->value.text, GFP_KERNEL);
        p = tb_property_find(dir, "vendorid", TB_PROPERTY_TYPE_TEXT);
        if (p)
                xd->vendor_name = kstrdup(p->value.text, GFP_KERNEL);

        return 0;
}

/* Called with @xd->lock held */
static void tb_xdomain_restore_paths(struct tb_xdomain *xd)
{
        if (!xd->resume)
                return;

        xd->resume = false;
        if (xd->transmit_path) {
                dev_dbg(&xd->dev, "re-establishing DMA path\n");
                tb_domain_approve_xdomain_paths(xd->tb, xd);
        }
}

static void tb_xdomain_get_properties(struct work_struct *work)
{
        struct tb_xdomain *xd = container_of(work, typeof(*xd),
                                             get_properties_work.work);
        struct tb_property_dir *dir;
        struct tb *tb = xd->tb;
        bool update = false;
        u32 *block = NULL;
        u32 gen = 0;
        int ret;

        ret = tb_xdp_properties_request(tb->ctl, xd->route, xd->local_uuid,
                                        xd->remote_uuid, xd->properties_retries,
                                        &block, &gen);
        if (ret < 0) {
                if (xd->properties_retries-- > 0) {
                        queue_delayed_work(xd->tb->wq, &xd->get_properties_work,
                                           msecs_to_jiffies(1000));
                } else {
                        /* Give up now */
                        dev_err(&xd->dev,
                                "failed read XDomain properties from %pUb\n",
                                xd->remote_uuid);
                }
                return;
        }

        xd->properties_retries = XDOMAIN_PROPERTIES_RETRIES;

        mutex_lock(&xd->lock);

        /* Only accept newer generation properties */
        if (xd->properties && gen <= xd->property_block_gen) {
                /*
                 * On resume it is likely that the properties block is
                 * not changed (unless the other end added or removed
                 * services). However, we need to make sure the existing
                 * DMA paths are restored properly.
                 */
                tb_xdomain_restore_paths(xd);
                goto err_free_block;
        }

        dir = tb_property_parse_dir(block, ret);
        if (!dir) {
                dev_err(&xd->dev, "failed to parse XDomain properties\n");
                goto err_free_block;
        }

        ret = populate_properties(xd, dir);
        if (ret) {
                dev_err(&xd->dev, "missing XDomain properties in response\n");
                goto err_free_dir;
        }

        /* Release the existing one */
        if (xd->properties) {
                tb_property_free_dir(xd->properties);
                update = true;
        }

        xd->properties = dir;
        xd->property_block_gen = gen;

        tb_xdomain_restore_paths(xd);

        mutex_unlock(&xd->lock);

        kfree(block);

        /*
         * Now the device should be ready enough so we can add it to the
         * bus and let userspace know about it. If the device is already
         * registered, we notify the userspace that it has changed.
         */
        if (!update) {
                if (device_add(&xd->dev)) {
                        dev_err(&xd->dev, "failed to add XDomain device\n");
                        return;
                }
        } else {
                kobject_uevent(&xd->dev.kobj, KOBJ_CHANGE);
        }

        enumerate_services(xd);
        return;

err_free_dir:
        tb_property_free_dir(dir);
err_free_block:
        kfree(block);
        mutex_unlock(&xd->lock);
}

static void tb_xdomain_properties_changed(struct work_struct *work)
{
        struct tb_xdomain *xd = container_of(work, typeof(*xd),
                                             properties_changed_work.work);
        int ret;

        ret = tb_xdp_properties_changed_request(xd->tb->ctl, xd->route,
                                xd->properties_changed_retries, xd->local_uuid);
        if (ret) {
                if (xd->properties_changed_retries-- > 0)
                        queue_delayed_work(xd->tb->wq,
                                           &xd->properties_changed_work,
                                           msecs_to_jiffies(1000));
                return;
        }

        xd->properties_changed_retries = XDOMAIN_PROPERTIES_CHANGED_RETRIES;
}

static ssize_t device_show(struct device *dev, struct device_attribute *attr,
                           char *buf)
{
        struct tb_xdomain *xd = container_of(dev, struct tb_xdomain, dev);

        return sprintf(buf, "%#x\n", xd->device);
}
static DEVICE_ATTR_RO(device);

static ssize_t
device_name_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct tb_xdomain *xd = container_of(dev, struct tb_xdomain, dev);
        int ret;

        if (mutex_lock_interruptible(&xd->lock))
                return -ERESTARTSYS;
        ret = sprintf(buf, "%s\n", xd->device_name ? xd->device_name : "");
        mutex_unlock(&xd->lock);

        return ret;
}
static DEVICE_ATTR_RO(device_name);

static ssize_t vendor_show(struct device *dev, struct device_attribute *attr,
                           char *buf)
{
        struct tb_xdomain *xd = container_of(dev, struct tb_xdomain, dev);

        return sprintf(buf, "%#x\n", xd->vendor);
}
static DEVICE_ATTR_RO(vendor);

static ssize_t
vendor_name_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct tb_xdomain *xd = container_of(dev, struct tb_xdomain, dev);
        int ret;

        if (mutex_lock_interruptible(&xd->lock))
                return -ERESTARTSYS;
        ret = sprintf(buf, "%s\n", xd->vendor_name ? xd->vendor_name : "");
        mutex_unlock(&xd->lock);

        return ret;
}
static DEVICE_ATTR_RO(vendor_name);

static ssize_t unique_id_show(struct device *dev, struct device_attribute *attr,
                              char *buf)
{
        struct tb_xdomain *xd = container_of(dev, struct tb_xdomain, dev);

        return sprintf(buf, "%pUb\n", xd->remote_uuid);
}
static DEVICE_ATTR_RO(unique_id);

static struct attribute *xdomain_attrs[] = {
        &dev_attr_device.attr,

        &dev_attr_device_name.attr,
        &dev_attr_unique_id.attr,
        &dev_attr_vendor.attr,
        &dev_attr_vendor_name.attr,
        NULL,
};

static struct attribute_group xdomain_attr_group = {
        .attrs = xdomain_attrs,
};

static const struct attribute_group *xdomain_attr_groups[] = {
        &xdomain_attr_group,
        NULL,
};

static void tb_xdomain_release(struct device *dev)
{
        struct tb_xdomain *xd = container_of(dev, struct tb_xdomain, dev);

        put_device(xd->dev.parent);

        tb_property_free_dir(xd->properties);
        ida_destroy(&xd->service_ids);

        kfree(xd->local_uuid);
        kfree(xd->remote_uuid);
        kfree(xd->device_name);
        kfree(xd->vendor_name);
        kfree(xd);
}

static void start_handshake(struct tb_xdomain *xd)
{
        xd->properties_retries = XDOMAIN_PROPERTIES_RETRIES;
        xd->properties_changed_retries = XDOMAIN_PROPERTIES_CHANGED_RETRIES;

        /* Start exchanging properties with the other host */
        queue_delayed_work(xd->tb->wq, &xd->properties_changed_work,
                           msecs_to_jiffies(100));
        queue_delayed_work(xd->tb->wq, &xd->get_properties_work,
                           msecs_to_jiffies(1000));
}

static void stop_handshake(struct tb_xdomain *xd)
{
        xd->properties_retries = 0;
        xd->properties_changed_retries = 0;

        cancel_delayed_work_sync(&xd->get_properties_work);
        cancel_delayed_work_sync(&xd->properties_changed_work);
}

static int __maybe_unused tb_xdomain_suspend(struct device *dev)
{
        stop_handshake(tb_to_xdomain(dev));
        return 0;
}

static int __maybe_unused tb_xdomain_resume(struct device *dev)
{
        struct tb_xdomain *xd = tb_to_xdomain(dev);

        /*
         * Ask tb_xdomain_get_properties() restore any existing DMA
         * paths after properties are re-read.
         */
        xd->resume = true;
        start_handshake(xd);

        return 0;
}

static const struct dev_pm_ops tb_xdomain_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(tb_xdomain_suspend, tb_xdomain_resume)
};

struct device_type tb_xdomain_type = {
        .name = "thunderbolt_xdomain",
        .release = tb_xdomain_release,
        .pm = &tb_xdomain_pm_ops,
};
EXPORT_SYMBOL_GPL(tb_xdomain_type);

/**
 * tb_xdomain_alloc() - Allocate new XDomain object
 * @tb: Domain where the XDomain belongs
 * @parent: Parent device (the switch through the connection to the
 *          other domain is reached).
 * @route: Route string used to reach the other domain
 * @local_uuid: Our local domain UUID
 * @remote_uuid: UUID of the other domain
 *
 * Allocates new XDomain structure and returns pointer to that. The
 * object must be released by calling tb_xdomain_put().
 */
struct tb_xdomain *tb_xdomain_alloc(struct tb *tb, struct device *parent,
                                    u64 route, const uuid_t *local_uuid,
                                    const uuid_t *remote_uuid)
{
        struct tb_xdomain *xd;

        xd = kzalloc(sizeof(*xd), GFP_KERNEL);
        if (!xd)
                return NULL;

        xd->tb = tb;
        xd->route = route;
        ida_init(&xd->service_ids);
        mutex_init(&xd->lock);
        INIT_DELAYED_WORK(&xd->get_properties_work, tb_xdomain_get_properties);
        INIT_DELAYED_WORK(&xd->properties_changed_work,
                          tb_xdomain_properties_changed);

        xd->local_uuid = kmemdup(local_uuid, sizeof(uuid_t), GFP_KERNEL);
        if (!xd->local_uuid)
                goto err_free;

        xd->remote_uuid = kmemdup(remote_uuid, sizeof(uuid_t), GFP_KERNEL);
        if (!xd->remote_uuid)
                goto err_free_local_uuid;

        device_initialize(&xd->dev);
        xd->dev.parent = get_device(parent);
        xd->dev.bus = &tb_bus_type;
        xd->dev.type = &tb_xdomain_type;
        xd->dev.groups = xdomain_attr_groups;
        dev_set_name(&xd->dev, "%u-%llx", tb->index, route);

        /*
         * This keeps the DMA powered on as long as we have active
         * connection to another host.
         */
        pm_runtime_set_active(&xd->dev);
        pm_runtime_get_noresume(&xd->dev);
        pm_runtime_enable(&xd->dev);

        return xd;

err_free_local_uuid:
        kfree(xd->local_uuid);
err_free:
        kfree(xd);

        return NULL;
}

/**
 * tb_xdomain_add() - Add XDomain to the bus
 * @xd: XDomain to add
 *
 * This function starts XDomain discovery protocol handshake and
 * eventually adds the XDomain to the bus. After calling this function
 * the caller needs to call tb_xdomain_remove() in order to remove and
 * release the object regardless whether the handshake succeeded or not.
 */
void tb_xdomain_add(struct tb_xdomain *xd)
{
        /* Start exchanging properties with the other host */
        start_handshake(xd);
}

static int unregister_service(struct device *dev, void *data)
{
        device_unregister(dev);
        return 0;
}

/**
 * tb_xdomain_remove() - Remove XDomain from the bus
 * @xd: XDomain to remove
 *
 * This will stop all ongoing configuration work and remove the XDomain
 * along with any services from the bus. When the last reference to @xd
 * is released the object will be released as well.
 */
void tb_xdomain_remove(struct tb_xdomain *xd)
{
        stop_handshake(xd);

        device_for_each_child_reverse(&xd->dev, xd, unregister_service);

        /*
         * Undo runtime PM here explicitly because it is possible that
         * the XDomain was never added to the bus and thus device_del()
         * is not called for it (device_del() would handle this otherwise).
         */
        pm_runtime_disable(&xd->dev);
        pm_runtime_put_noidle(&xd->dev);
        pm_runtime_set_suspended(&xd->dev);

        if (!device_is_registered(&xd->dev))
                put_device(&xd->dev);
        else
                device_unregister(&xd->dev);
}

/**
 * tb_xdomain_enable_paths() - Enable DMA paths for XDomain connection
 * @xd: XDomain connection
 * @transmit_path: HopID of the transmit path the other end is using to
 *                 send packets
 * @transmit_ring: DMA ring used to receive packets from the other end
 * @receive_path: HopID of the receive path the other end is using to
 *                receive packets
 * @receive_ring: DMA ring used to send packets to the other end
 *
 * The function enables DMA paths accordingly so that after successful
 * return the caller can send and receive packets using high-speed DMA
 * path.
 *
 * Return: %0 in case of success and negative errno in case of error
 */
int tb_xdomain_enable_paths(struct tb_xdomain *xd, u16 transmit_path,
                            u16 transmit_ring, u16 receive_path,
                            u16 receive_ring)
{
        int ret;

        mutex_lock(&xd->lock);

        if (xd->transmit_path) {
                ret = xd->transmit_path == transmit_path ? 0 : -EBUSY;
                goto exit_unlock;
        }

        xd->transmit_path = transmit_path;
        xd->transmit_ring = transmit_ring;
        xd->receive_path = receive_path;
        xd->receive_ring = receive_ring;

        ret = tb_domain_approve_xdomain_paths(xd->tb, xd);

exit_unlock:
        mutex_unlock(&xd->lock);

        return ret;
}
EXPORT_SYMBOL_GPL(tb_xdomain_enable_paths);

/**
 * tb_xdomain_disable_paths() - Disable DMA paths for XDomain connection
 * @xd: XDomain connection
 *
 * This does the opposite of tb_xdomain_enable_paths(). After call to
 * this the caller is not expected to use the rings anymore.
 *
 * Return: %0 in case of success and negative errno in case of error
 */
int tb_xdomain_disable_paths(struct tb_xdomain *xd)
{
        int ret = 0;

        mutex_lock(&xd->lock);
        if (xd->transmit_path) {
                xd->transmit_path = 0;
                xd->transmit_ring = 0;
                xd->receive_path = 0;
                xd->receive_ring = 0;

                ret = tb_domain_disconnect_xdomain_paths(xd->tb, xd);
        }
        mutex_unlock(&xd->lock);

        return ret;
}
EXPORT_SYMBOL_GPL(tb_xdomain_disable_paths);

struct tb_xdomain_lookup {
        const uuid_t *uuid;
        u8 link;
        u8 depth;
        u64 route;
};

static struct tb_xdomain *switch_find_xdomain(struct tb_switch *sw,
        const struct tb_xdomain_lookup *lookup)
{
        int i;

        for (i = 1; i <= sw->config.max_port_number; i++) {
                struct tb_port *port = &sw->ports[i];
                struct tb_xdomain *xd;

                if (tb_is_upstream_port(port))
                        continue;

                if (port->xdomain) {
                        xd = port->xdomain;

                        if (lookup->uuid) {
                                if (uuid_equal(xd->remote_uuid, lookup->uuid))
                                        return xd;
                        } else if (lookup->link &&
                                   lookup->link == xd->link &&
                                   lookup->depth == xd->depth) {
                                return xd;
                        } else if (lookup->route &&
                                   lookup->route == xd->route) {
                                return xd;
                        }
                } else if (port->remote) {
                        xd = switch_find_xdomain(port->remote->sw, lookup);
                        if (xd)
                                return xd;
                }
        }

        return NULL;
}

/**
 * tb_xdomain_find_by_uuid() - Find an XDomain by UUID
 * @tb: Domain where the XDomain belongs to
 * @uuid: UUID to look for
 *
 * Finds XDomain by walking through the Thunderbolt topology below @tb.
 * The returned XDomain will have its reference count increased so the
 * caller needs to call tb_xdomain_put() when it is done with the
 * object.
 *
 * This will find all XDomains including the ones that are not yet added
 * to the bus (handshake is still in progress).
 *
 * The caller needs to hold @tb->lock.
 */
struct tb_xdomain *tb_xdomain_find_by_uuid(struct tb *tb, const uuid_t *uuid)
{
        struct tb_xdomain_lookup lookup;
        struct tb_xdomain *xd;

        memset(&lookup, 0, sizeof(lookup));
        lookup.uuid = uuid;

        xd = switch_find_xdomain(tb->root_switch, &lookup);
        return tb_xdomain_get(xd);
}
EXPORT_SYMBOL_GPL(tb_xdomain_find_by_uuid);

/**
 * tb_xdomain_find_by_link_depth() - Find an XDomain by link and depth
 * @tb: Domain where the XDomain belongs to
 * @link: Root switch link number
 * @depth: Depth in the link
 *
 * Finds XDomain by walking through the Thunderbolt topology below @tb.
 * The returned XDomain will have its reference count increased so the
 * caller needs to call tb_xdomain_put() when it is done with the
 * object.
 *
 * This will find all XDomains including the ones that are not yet added
 * to the bus (handshake is still in progress).
 *
 * The caller needs to hold @tb->lock.
 */
struct tb_xdomain *tb_xdomain_find_by_link_depth(struct tb *tb, u8 link,
                                                 u8 depth)
{
        struct tb_xdomain_lookup lookup;
        struct tb_xdomain *xd;

        memset(&lookup, 0, sizeof(lookup));
        lookup.link = link;
        lookup.depth = depth;

        xd = switch_find_xdomain(tb->root_switch, &lookup);
        return tb_xdomain_get(xd);
}

/**
 * tb_xdomain_find_by_route() - Find an XDomain by route string
 * @tb: Domain where the XDomain belongs to
 * @route: XDomain route string
 *
 * Finds XDomain by walking through the Thunderbolt topology below @tb.
 * The returned XDomain will have its reference count increased so the
 * caller needs to call tb_xdomain_put() when it is done with the
 * object.
 *
 * This will find all XDomains including the ones that are not yet added
 * to the bus (handshake is still in progress).
 *
 * The caller needs to hold @tb->lock.
 */
struct tb_xdomain *tb_xdomain_find_by_route(struct tb *tb, u64 route)
{
        struct tb_xdomain_lookup lookup;
        struct tb_xdomain *xd;

        memset(&lookup, 0, sizeof(lookup));
        lookup.route = route;

        xd = switch_find_xdomain(tb->root_switch, &lookup);
        return tb_xdomain_get(xd);
}
EXPORT_SYMBOL_GPL(tb_xdomain_find_by_route);

bool tb_xdomain_handle_request(struct tb *tb, enum tb_cfg_pkg_type type,
                               const void *buf, size_t size)
{
        const struct tb_protocol_handler *handler, *tmp;
        const struct tb_xdp_header *hdr = buf;
        unsigned int length;
        int ret = 0;

        /* We expect the packet is at least size of the header */
        length = hdr->xd_hdr.length_sn & TB_XDOMAIN_LENGTH_MASK;
        if (length != size / 4 - sizeof(hdr->xd_hdr) / 4)
                return true;
        if (length < sizeof(*hdr) / 4 - sizeof(hdr->xd_hdr) / 4)
                return true;

        /*
         * Handle XDomain discovery protocol packets directly here. For
         * other protocols (based on their UUID) we call registered
         * handlers in turn.
         */
        if (uuid_equal(&hdr->uuid, &tb_xdp_uuid)) {
                if (type == TB_CFG_PKG_XDOMAIN_REQ) {
                        tb_xdp_schedule_request(tb, hdr, size);
                        return true;
                }
                return false;
        }

        mutex_lock(&xdomain_lock);
        list_for_each_entry_safe(handler, tmp, &protocol_handlers, list) {
                if (!uuid_equal(&hdr->uuid, handler->uuid))
                        continue;

                mutex_unlock(&xdomain_lock);
                ret = handler->callback(buf, size, handler->data);
                mutex_lock(&xdomain_lock);

                if (ret)
                        break;
        }
        mutex_unlock(&xdomain_lock);

        return ret > 0;
}

static int rebuild_property_block(void)
{
        u32 *block, len;
        int ret;

        ret = tb_property_format_dir(xdomain_property_dir, NULL, 0);
        if (ret < 0)
                return ret;

        len = ret;

        block = kcalloc(len, sizeof(u32), GFP_KERNEL);
        if (!block)
                return -ENOMEM;

        ret = tb_property_format_dir(xdomain_property_dir, block, len);
        if (ret) {
                kfree(block);
                return ret;
        }

        kfree(xdomain_property_block);
        xdomain_property_block = block;
        xdomain_property_block_len = len;
        xdomain_property_block_gen++;

        return 0;
}

static int update_xdomain(struct device *dev, void *data)
{
        struct tb_xdomain *xd;

        xd = tb_to_xdomain(dev);
        if (xd) {
                queue_delayed_work(xd->tb->wq, &xd->properties_changed_work,
                                   msecs_to_jiffies(50));
        }

        return 0;
}

static void update_all_xdomains(void)
{
        bus_for_each_dev(&tb_bus_type, NULL, NULL, update_xdomain);
}

static bool remove_directory(const char *key, const struct tb_property_dir *dir)
{
        struct tb_property *p;

        p = tb_property_find(xdomain_property_dir, key,
                             TB_PROPERTY_TYPE_DIRECTORY);
        if (p && p->value.dir == dir) {
                tb_property_remove(p);
                return true;
        }
        return false;
}

/**
 * tb_register_property_dir() - Register property directory to the host
 * @key: Key (name) of the directory to add
 * @dir: Directory to add
 *
 * Service drivers can use this function to add new property directory
 * to the host available properties. The other connected hosts are
 * notified so they can re-read properties of this host if they are
 * interested.
 *
 * Return: %0 on success and negative errno on failure
 */
int tb_register_property_dir(const char *key, struct tb_property_dir *dir)
{
        int ret;

        if (WARN_ON(!xdomain_property_dir))
                return -EAGAIN;

        if (!key || strlen(key) > 8)
                return -EINVAL;

        mutex_lock(&xdomain_lock);
        if (tb_property_find(xdomain_property_dir, key,
                             TB_PROPERTY_TYPE_DIRECTORY)) {
                ret = -EEXIST;
                goto err_unlock;
        }

        ret = tb_property_add_dir(xdomain_property_dir, key, dir);
        if (ret)
                goto err_unlock;

        ret = rebuild_property_block();
        if (ret) {
                remove_directory(key, dir);
                goto err_unlock;
        }

        mutex_unlock(&xdomain_lock);
        update_all_xdomains();
        return 0;

err_unlock:
        mutex_unlock(&xdomain_lock);
        return ret;
}
EXPORT_SYMBOL_GPL(tb_register_property_dir);

/**
 * tb_unregister_property_dir() - Removes property directory from host
 * @key: Key (name) of the directory
 * @dir: Directory to remove
 *
 * This will remove the existing directory from this host and notify the
 * connected hosts about the change.
 */
void tb_unregister_property_dir(const char *key, struct tb_property_dir *dir)
{
        int ret = 0;

        mutex_lock(&xdomain_lock);
        if (remove_directory(key, dir))
                ret = rebuild_property_block();
        mutex_unlock(&xdomain_lock);

        if (!ret)
                update_all_xdomains();
}
EXPORT_SYMBOL_GPL(tb_unregister_property_dir);

int tb_xdomain_init(void)
{
        int ret;

        xdomain_property_dir = tb_property_create_dir(NULL);
        if (!xdomain_property_dir)
                return -ENOMEM;

        /*
         * Initialize standard set of properties without any service
         * directories. Those will be added by service drivers
         * themselves when they are loaded.
         */
        tb_property_add_immediate(xdomain_property_dir, "vendorid",
                                  PCI_VENDOR_ID_INTEL);
        tb_property_add_text(xdomain_property_dir, "vendorid", "Intel Corp.");
        tb_property_add_immediate(xdomain_property_dir, "deviceid", 0x1);
        tb_property_add_text(xdomain_property_dir, "deviceid",
                             utsname()->nodename);
        tb_property_add_immediate(xdomain_property_dir, "devicerv", 0x80000100);

        ret = rebuild_property_block();
        if (ret) {
                tb_property_free_dir(xdomain_property_dir);
                xdomain_property_dir = NULL;
        }

        return ret;
}

void tb_xdomain_exit(void)
{
        kfree(xdomain_property_block);
        tb_property_free_dir(xdomain_property_dir);
}