/*
 * Thunderbolt bus support
 *
 * Copyright (C) 2017, Intel Corporation
 * Author:  Mika Westerberg <mika.westerberg@linux.intel.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/device.h>
#include <linux/idr.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <crypto/hash.h>

#include "tb.h"

static DEFINE_IDA(tb_domain_ida);

static bool match_service_id(const struct tb_service_id *id,
                             const struct tb_service *svc)
{
        if (id->match_flags & TBSVC_MATCH_PROTOCOL_KEY) {
                if (strcmp(id->protocol_key, svc->key))
                        return false;
        }

        if (id->match_flags & TBSVC_MATCH_PROTOCOL_ID) {
                if (id->protocol_id != svc->prtcid)
                        return false;
        }

        if (id->match_flags & TBSVC_MATCH_PROTOCOL_VERSION) {
                if (id->protocol_version != svc->prtcvers)
                        return false;
        }

        if (id->match_flags & TBSVC_MATCH_PROTOCOL_VERSION) {
                if (id->protocol_revision != svc->prtcrevs)
                        return false;
        }

        return true;
}

static const struct tb_service_id *__tb_service_match(struct device *dev,
                                                      struct device_driver *drv)
{
        struct tb_service_driver *driver;
        const struct tb_service_id *ids;
        struct tb_service *svc;

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

        driver = container_of(drv, struct tb_service_driver, driver);
        if (!driver->id_table)
                return NULL;

        for (ids = driver->id_table; ids->match_flags != 0; ids++) {
                if (match_service_id(ids, svc))
                        return ids;
        }

        return NULL;
}

static int tb_service_match(struct device *dev, struct device_driver *drv)
{
        return !!__tb_service_match(dev, drv);
}

static int tb_service_probe(struct device *dev)
{
        struct tb_service *svc = tb_to_service(dev);
        struct tb_service_driver *driver;
        const struct tb_service_id *id;

        driver = container_of(dev->driver, struct tb_service_driver, driver);
        id = __tb_service_match(dev, &driver->driver);

        return driver->probe(svc, id);
}

static int tb_service_remove(struct device *dev)
{
        struct tb_service *svc = tb_to_service(dev);
        struct tb_service_driver *driver;

        driver = container_of(dev->driver, struct tb_service_driver, driver);
        if (driver->remove)
                driver->remove(svc);

        return 0;
}

static void tb_service_shutdown(struct device *dev)
{
        struct tb_service_driver *driver;
        struct tb_service *svc;

        svc = tb_to_service(dev);
        if (!svc || !dev->driver)
                return;

        driver = container_of(dev->driver, struct tb_service_driver, driver);
        if (driver->shutdown)
                driver->shutdown(svc);
}

static const char * const tb_security_names[] = {
        [TB_SECURITY_NONE] = "none",
        [TB_SECURITY_USER] = "user",
        [TB_SECURITY_SECURE] = "secure",
        [TB_SECURITY_DPONLY] = "dponly",
        [TB_SECURITY_USBONLY] = "usbonly",
};

static ssize_t boot_acl_show(struct device *dev, struct device_attribute *attr,
                             char *buf)
{
        struct tb *tb = container_of(dev, struct tb, dev);
        uuid_t *uuids;
        ssize_t ret;
        int i;

        uuids = kcalloc(tb->nboot_acl, sizeof(uuid_t), GFP_KERNEL);
        if (!uuids)
                return -ENOMEM;

        pm_runtime_get_sync(&tb->dev);

        if (mutex_lock_interruptible(&tb->lock)) {
                ret = -ERESTARTSYS;
                goto out;
        }
        ret = tb->cm_ops->get_boot_acl(tb, uuids, tb->nboot_acl);
        if (ret) {
                mutex_unlock(&tb->lock);
                goto out;
        }
        mutex_unlock(&tb->lock);

        for (ret = 0, i = 0; i < tb->nboot_acl; i++) {
                if (!uuid_is_null(&uuids[i]))
                        ret += snprintf(buf + ret, PAGE_SIZE - ret, "%pUb",
                                        &uuids[i]);

                ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s",
                               i < tb->nboot_acl - 1 ? "," : "\n");
        }

out:
        pm_runtime_mark_last_busy(&tb->dev);
        pm_runtime_put_autosuspend(&tb->dev);
        kfree(uuids);

        return ret;
}

static ssize_t boot_acl_store(struct device *dev, struct device_attribute *attr,
                              const char *buf, size_t count)
{
        struct tb *tb = container_of(dev, struct tb, dev);
        char *str, *s, *uuid_str;
        ssize_t ret = 0;
        uuid_t *acl;
        int i = 0;

        /*
         * Make sure the value is not bigger than tb->nboot_acl * UUID
         * length + commas and optional "\n". Also the smallest allowable
         * string is tb->nboot_acl * ",".
         */
        if (count > (UUID_STRING_LEN + 1) * tb->nboot_acl + 1)
                return -EINVAL;
        if (count < tb->nboot_acl - 1)
                return -EINVAL;

        str = kstrdup(buf, GFP_KERNEL);
        if (!str)
                return -ENOMEM;

        acl = kcalloc(tb->nboot_acl, sizeof(uuid_t), GFP_KERNEL);
        if (!acl) {
                ret = -ENOMEM;
                goto err_free_str;
        }

        uuid_str = strim(str);
        while ((s = strsep(&uuid_str, ",")) != NULL && i < tb->nboot_acl) {
                size_t len = strlen(s);

                if (len) {
                        if (len != UUID_STRING_LEN) {
                                ret = -EINVAL;
                                goto err_free_acl;
                        }
                        ret = uuid_parse(s, &acl[i]);
                        if (ret)
                                goto err_free_acl;
                }

                i++;
        }

        if (s || i < tb->nboot_acl) {
                ret = -EINVAL;
                goto err_free_acl;
        }

        pm_runtime_get_sync(&tb->dev);

        if (mutex_lock_interruptible(&tb->lock)) {
                ret = -ERESTARTSYS;
                goto err_rpm_put;
        }
        ret = tb->cm_ops->set_boot_acl(tb, acl, tb->nboot_acl);
        if (!ret) {
                /* Notify userspace about the change */
                kobject_uevent(&tb->dev.kobj, KOBJ_CHANGE);
        }
        mutex_unlock(&tb->lock);

err_rpm_put:
        pm_runtime_mark_last_busy(&tb->dev);
        pm_runtime_put_autosuspend(&tb->dev);
err_free_acl:
        kfree(acl);
err_free_str:
        kfree(str);

        return ret ?: count;
}
static DEVICE_ATTR_RW(boot_acl);

static ssize_t security_show(struct device *dev, struct device_attribute *attr,
                             char *buf)
{
        struct tb *tb = container_of(dev, struct tb, dev);
        const char *name = "unknown";

        if (tb->security_level < ARRAY_SIZE(tb_security_names))
                name = tb_security_names[tb->security_level];

        return sprintf(buf, "%s\n", name);
}
static DEVICE_ATTR_RO(security);

static struct attribute *domain_attrs[] = {
        &dev_attr_boot_acl.attr,
        &dev_attr_security.attr,
        NULL,
};

static umode_t domain_attr_is_visible(struct kobject *kobj,
                                      struct attribute *attr, int n)
{
        struct device *dev = container_of(kobj, struct device, kobj);
        struct tb *tb = container_of(dev, struct tb, dev);

        if (attr == &dev_attr_boot_acl.attr) {
                if (tb->nboot_acl &&
                    tb->cm_ops->get_boot_acl &&
                    tb->cm_ops->set_boot_acl)
                        return attr->mode;
                return 0;
        }

        return attr->mode;
}

static struct attribute_group domain_attr_group = {
        .is_visible = domain_attr_is_visible,
        .attrs = domain_attrs,
};

static const struct attribute_group *domain_attr_groups[] = {
        &domain_attr_group,
        NULL,
};

struct bus_type tb_bus_type = {
        .name = "thunderbolt",
        .match = tb_service_match,
        .probe = tb_service_probe,
        .remove = tb_service_remove,
        .shutdown = tb_service_shutdown,
};

static void tb_domain_release(struct device *dev)
{
        struct tb *tb = container_of(dev, struct tb, dev);

        tb_ctl_free(tb->ctl);
        destroy_workqueue(tb->wq);
        ida_simple_remove(&tb_domain_ida, tb->index);
        mutex_destroy(&tb->lock);
        kfree(tb);
}

struct device_type tb_domain_type = {
        .name = "thunderbolt_domain",
        .release = tb_domain_release,
};

/**
 * tb_domain_alloc() - Allocate a domain
 * @nhi: Pointer to the host controller
 * @privsize: Size of the connection manager private data
 *
 * Allocates and initializes a new Thunderbolt domain. Connection
 * managers are expected to call this and then fill in @cm_ops
 * accordingly.
 *
 * Call tb_domain_put() to release the domain before it has been added
 * to the system.
 *
 * Return: allocated domain structure on %NULL in case of error
 */
struct tb *tb_domain_alloc(struct tb_nhi *nhi, size_t privsize)
{
        struct tb *tb;

        /*
         * Make sure the structure sizes map with that the hardware
         * expects because bit-fields are being used.
         */
        BUILD_BUG_ON(sizeof(struct tb_regs_switch_header) != 5 * 4);
        BUILD_BUG_ON(sizeof(struct tb_regs_port_header) != 8 * 4);
        BUILD_BUG_ON(sizeof(struct tb_regs_hop) != 2 * 4);

        tb = kzalloc(sizeof(*tb) + privsize, GFP_KERNEL);
        if (!tb)
                return NULL;

        tb->nhi = nhi;
        mutex_init(&tb->lock);

        tb->index = ida_simple_get(&tb_domain_ida, 0, 0, GFP_KERNEL);
        if (tb->index < 0)
                goto err_free;

        tb->wq = alloc_ordered_workqueue("thunderbolt%d", 0, tb->index);
        if (!tb->wq)
                goto err_remove_ida;

        tb->dev.parent = &nhi->pdev->dev;
        tb->dev.bus = &tb_bus_type;
        tb->dev.type = &tb_domain_type;
        tb->dev.groups = domain_attr_groups;
        dev_set_name(&tb->dev, "domain%d", tb->index);
        device_initialize(&tb->dev);

        return tb;

err_remove_ida:
        ida_simple_remove(&tb_domain_ida, tb->index);
err_free:
        kfree(tb);

        return NULL;
}

static bool tb_domain_event_cb(void *data, enum tb_cfg_pkg_type type,
                               const void *buf, size_t size)
{
        struct tb *tb = data;

        if (!tb->cm_ops->handle_event) {
                tb_warn(tb, "domain does not have event handler\n");
                return true;
        }

        switch (type) {
        case TB_CFG_PKG_XDOMAIN_REQ:
        case TB_CFG_PKG_XDOMAIN_RESP:
                return tb_xdomain_handle_request(tb, type, buf, size);

        default:
                tb->cm_ops->handle_event(tb, type, buf, size);
        }

        return true;
}

/**
 * tb_domain_add() - Add domain to the system
 * @tb: Domain to add
 *
 * Starts the domain and adds it to the system. Hotplugging devices will
 * work after this has been returned successfully. In order to remove
 * and release the domain after this function has been called, call
 * tb_domain_remove().
 *
 * Return: %0 in case of success and negative errno in case of error
 */
int tb_domain_add(struct tb *tb)
{
        int ret;

        if (WARN_ON(!tb->cm_ops))
                return -EINVAL;

        mutex_lock(&tb->lock);

        tb->ctl = tb_ctl_alloc(tb->nhi, tb_domain_event_cb, tb);
        if (!tb->ctl) {
                ret = -ENOMEM;
                goto err_unlock;
        }

        /*
         * tb_schedule_hotplug_handler may be called as soon as the config
         * channel is started. Thats why we have to hold the lock here.
         */
        tb_ctl_start(tb->ctl);

        if (tb->cm_ops->driver_ready) {
                ret = tb->cm_ops->driver_ready(tb);
                if (ret)
                        goto err_ctl_stop;
        }

        ret = device_add(&tb->dev);
        if (ret)
                goto err_ctl_stop;

        /* Start the domain */
        if (tb->cm_ops->start) {
                ret = tb->cm_ops->start(tb);
                if (ret)
                        goto err_domain_del;
        }

        /* This starts event processing */
        mutex_unlock(&tb->lock);

        pm_runtime_no_callbacks(&tb->dev);
        pm_runtime_set_active(&tb->dev);
        pm_runtime_enable(&tb->dev);
        pm_runtime_set_autosuspend_delay(&tb->dev, TB_AUTOSUSPEND_DELAY);
        pm_runtime_mark_last_busy(&tb->dev);
        pm_runtime_use_autosuspend(&tb->dev);

        return 0;

err_domain_del:
        device_del(&tb->dev);
err_ctl_stop:
        tb_ctl_stop(tb->ctl);
err_unlock:
        mutex_unlock(&tb->lock);

        return ret;
}

/**
 * tb_domain_remove() - Removes and releases a domain
 * @tb: Domain to remove
 *
 * Stops the domain, removes it from the system and releases all
 * resources once the last reference has been released.
 */
void tb_domain_remove(struct tb *tb)
{
        mutex_lock(&tb->lock);
        if (tb->cm_ops->stop)
                tb->cm_ops->stop(tb);
        /* Stop the domain control traffic */
        tb_ctl_stop(tb->ctl);
        mutex_unlock(&tb->lock);

        flush_workqueue(tb->wq);
        device_unregister(&tb->dev);
}

/**
 * tb_domain_suspend_noirq() - Suspend a domain
 * @tb: Domain to suspend
 *
 * Suspends all devices in the domain and stops the control channel.
 */
int tb_domain_suspend_noirq(struct tb *tb)
{
        int ret = 0;

        /*
         * The control channel interrupt is left enabled during suspend
         * and taking the lock here prevents any events happening before
         * we actually have stopped the domain and the control channel.
         */
        mutex_lock(&tb->lock);
        if (tb->cm_ops->suspend_noirq)
                ret = tb->cm_ops->suspend_noirq(tb);
        if (!ret)
                tb_ctl_stop(tb->ctl);
        mutex_unlock(&tb->lock);

        return ret;
}

/**
 * tb_domain_resume_noirq() - Resume a domain
 * @tb: Domain to resume
 *
 * Re-starts the control channel, and resumes all devices connected to
 * the domain.
 */
int tb_domain_resume_noirq(struct tb *tb)
{
        int ret = 0;

        mutex_lock(&tb->lock);
        tb_ctl_start(tb->ctl);
        if (tb->cm_ops->resume_noirq)
                ret = tb->cm_ops->resume_noirq(tb);
        mutex_unlock(&tb->lock);

        return ret;
}

int tb_domain_suspend(struct tb *tb)
{
        return tb->cm_ops->suspend ? tb->cm_ops->suspend(tb) : 0;
}

void tb_domain_complete(struct tb *tb)
{
        if (tb->cm_ops->complete)
                tb->cm_ops->complete(tb);
}

int tb_domain_runtime_suspend(struct tb *tb)
{
        if (tb->cm_ops->runtime_suspend) {
                int ret = tb->cm_ops->runtime_suspend(tb);
                if (ret)
                        return ret;
        }
        tb_ctl_stop(tb->ctl);
        return 0;
}

int tb_domain_runtime_resume(struct tb *tb)
{
        tb_ctl_start(tb->ctl);
        if (tb->cm_ops->runtime_resume) {
                int ret = tb->cm_ops->runtime_resume(tb);
                if (ret)
                        return ret;
        }
        return 0;
}

/**
 * tb_domain_approve_switch() - Approve switch
 * @tb: Domain the switch belongs to
 * @sw: Switch to approve
 *
 * This will approve switch by connection manager specific means. In
 * case of success the connection manager will create tunnels for all
 * supported protocols.
 */
int tb_domain_approve_switch(struct tb *tb, struct tb_switch *sw)
{
        struct tb_switch *parent_sw;

        if (!tb->cm_ops->approve_switch)
                return -EPERM;

        /* The parent switch must be authorized before this one */
        parent_sw = tb_to_switch(sw->dev.parent);
        if (!parent_sw || !parent_sw->authorized)
                return -EINVAL;

        return tb->cm_ops->approve_switch(tb, sw);
}

/**
 * tb_domain_approve_switch_key() - Approve switch and add key
 * @tb: Domain the switch belongs to
 * @sw: Switch to approve
 *
 * For switches that support secure connect, this function first adds
 * key to the switch NVM using connection manager specific means. If
 * adding the key is successful, the switch is approved and connected.
 *
 * Return: %0 on success and negative errno in case of failure.
 */
int tb_domain_approve_switch_key(struct tb *tb, struct tb_switch *sw)
{
        struct tb_switch *parent_sw;
        int ret;

        if (!tb->cm_ops->approve_switch || !tb->cm_ops->add_switch_key)
                return -EPERM;

        /* The parent switch must be authorized before this one */
        parent_sw = tb_to_switch(sw->dev.parent);
        if (!parent_sw || !parent_sw->authorized)
                return -EINVAL;

        ret = tb->cm_ops->add_switch_key(tb, sw);
        if (ret)
                return ret;

        return tb->cm_ops->approve_switch(tb, sw);
}

/**
 * tb_domain_challenge_switch_key() - Challenge and approve switch
 * @tb: Domain the switch belongs to
 * @sw: Switch to approve
 *
 * For switches that support secure connect, this function generates
 * random challenge and sends it to the switch. The switch responds to
 * this and if the response matches our random challenge, the switch is
 * approved and connected.
 *
 * Return: %0 on success and negative errno in case of failure.
 */
int tb_domain_challenge_switch_key(struct tb *tb, struct tb_switch *sw)
{
        u8 challenge[TB_SWITCH_KEY_SIZE];
        u8 response[TB_SWITCH_KEY_SIZE];
        u8 hmac[TB_SWITCH_KEY_SIZE];
        struct tb_switch *parent_sw;
        struct crypto_shash *tfm;
        struct shash_desc *shash;
        int ret;

        if (!tb->cm_ops->approve_switch || !tb->cm_ops->challenge_switch_key)
                return -EPERM;

        /* The parent switch must be authorized before this one */
        parent_sw = tb_to_switch(sw->dev.parent);
        if (!parent_sw || !parent_sw->authorized)
                return -EINVAL;

        get_random_bytes(challenge, sizeof(challenge));
        ret = tb->cm_ops->challenge_switch_key(tb, sw, challenge, response);
        if (ret)
                return ret;

        tfm = crypto_alloc_shash("hmac(sha256)", 0, 0);
        if (IS_ERR(tfm))
                return PTR_ERR(tfm);

        ret = crypto_shash_setkey(tfm, sw->key, TB_SWITCH_KEY_SIZE);
        if (ret)
                goto err_free_tfm;

        shash = kzalloc(sizeof(*shash) + crypto_shash_descsize(tfm),
                        GFP_KERNEL);
        if (!shash) {
                ret = -ENOMEM;
                goto err_free_tfm;
        }

        shash->tfm = tfm;
        shash->flags = CRYPTO_TFM_REQ_MAY_SLEEP;

        memset(hmac, 0, sizeof(hmac));
        ret = crypto_shash_digest(shash, challenge, sizeof(hmac), hmac);
        if (ret)
                goto err_free_shash;

        /* The returned HMAC must match the one we calculated */
        if (memcmp(response, hmac, sizeof(hmac))) {
                ret = -EKEYREJECTED;
                goto err_free_shash;
        }

        crypto_free_shash(tfm);
        kfree(shash);

        return tb->cm_ops->approve_switch(tb, sw);

err_free_shash:
        kfree(shash);
err_free_tfm:
        crypto_free_shash(tfm);

        return ret;
}

/**
 * tb_domain_disconnect_pcie_paths() - Disconnect all PCIe paths
 * @tb: Domain whose PCIe paths to disconnect
 *
 * This needs to be called in preparation for NVM upgrade of the host
 * controller. Makes sure all PCIe paths are disconnected.
 *
 * Return %0 on success and negative errno in case of error.
 */
int tb_domain_disconnect_pcie_paths(struct tb *tb)
{
        if (!tb->cm_ops->disconnect_pcie_paths)
                return -EPERM;

        return tb->cm_ops->disconnect_pcie_paths(tb);
}

/**
 * tb_domain_approve_xdomain_paths() - Enable DMA paths for XDomain
 * @tb: Domain enabling the DMA paths
 * @xd: XDomain DMA paths are created to
 *
 * Calls connection manager specific method to enable DMA paths to the
 * XDomain in question.
 *
 * Return: 0% in case of success and negative errno otherwise. In
 * particular returns %-ENOTSUPP if the connection manager
 * implementation does not support XDomains.
 */
int tb_domain_approve_xdomain_paths(struct tb *tb, struct tb_xdomain *xd)
{
        if (!tb->cm_ops->approve_xdomain_paths)
                return -ENOTSUPP;

        return tb->cm_ops->approve_xdomain_paths(tb, xd);
}

/**
 * tb_domain_disconnect_xdomain_paths() - Disable DMA paths for XDomain
 * @tb: Domain disabling the DMA paths
 * @xd: XDomain whose DMA paths are disconnected
 *
 * Calls connection manager specific method to disconnect DMA paths to
 * the XDomain in question.
 *
 * Return: 0% in case of success and negative errno otherwise. In
 * particular returns %-ENOTSUPP if the connection manager
 * implementation does not support XDomains.
 */
int tb_domain_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd)
{
        if (!tb->cm_ops->disconnect_xdomain_paths)
                return -ENOTSUPP;

        return tb->cm_ops->disconnect_xdomain_paths(tb, xd);
}

static int disconnect_xdomain(struct device *dev, void *data)
{
        struct tb_xdomain *xd;
        struct tb *tb = data;
        int ret = 0;

        xd = tb_to_xdomain(dev);
        if (xd && xd->tb == tb)
                ret = tb_xdomain_disable_paths(xd);

        return ret;
}

/**
 * tb_domain_disconnect_all_paths() - Disconnect all paths for the domain
 * @tb: Domain whose paths are disconnected
 *
 * This function can be used to disconnect all paths (PCIe, XDomain) for
 * example in preparation for host NVM firmware upgrade. After this is
 * called the paths cannot be established without resetting the switch.
 *
 * Return: %0 in case of success and negative errno otherwise.
 */
int tb_domain_disconnect_all_paths(struct tb *tb)
{
        int ret;

        ret = tb_domain_disconnect_pcie_paths(tb);
        if (ret)
                return ret;

        return bus_for_each_dev(&tb_bus_type, NULL, tb, disconnect_xdomain);
}

int tb_domain_init(void)
{
        int ret;

        ret = tb_xdomain_init();
        if (ret)
                return ret;
        ret = bus_register(&tb_bus_type);
        if (ret)
                tb_xdomain_exit();

        return ret;
}

void tb_domain_exit(void)
{
        bus_unregister(&tb_bus_type);
        ida_destroy(&tb_domain_ida);
        tb_switch_exit();
        tb_xdomain_exit();
}