// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020 The Linux Foundation. All rights reserved.
 */

#include <linux/cleanup.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/workqueue.h>

#include "pdr_internal.h"

struct pdr_service {
        char service_name[SERVREG_NAME_LENGTH + 1];
        char service_path[SERVREG_NAME_LENGTH + 1];

        struct sockaddr_qrtr addr;

        unsigned int instance;
        unsigned int service;
        u8 service_data_valid;
        u32 service_data;
        int state;

        bool need_notifier_register;
        bool need_notifier_remove;
        bool need_locator_lookup;
        bool service_connected;

        struct list_head node;
};

struct pdr_handle {
        struct qmi_handle locator_hdl;
        struct qmi_handle notifier_hdl;

        struct sockaddr_qrtr locator_addr;

        struct list_head lookups;
        struct list_head indack_list;

        /* control access to pdr lookup/indack lists */
        struct mutex list_lock;

        /* serialize pd status invocation */
        struct mutex status_lock;

        /* control access to the locator state */
        struct mutex lock;

        bool locator_init_complete;

        struct work_struct locator_work;
        struct work_struct notifier_work;
        struct work_struct indack_work;

        struct workqueue_struct *notifier_wq;
        struct workqueue_struct *indack_wq;

        void (*status)(int state, char *service_path, void *priv);
        void *priv;
};

struct pdr_list_node {
        enum servreg_service_state curr_state;
        u16 transaction_id;
        struct pdr_service *pds;
        struct list_head node;
};

static int pdr_locator_new_server(struct qmi_handle *qmi,
                                  struct qmi_service *svc)
{
        struct pdr_handle *pdr = container_of(qmi, struct pdr_handle,
                                              locator_hdl);

        mutex_lock(&pdr->lock);
        /* Create a local client port for QMI communication */
        pdr->locator_addr.sq_family = AF_QIPCRTR;
        pdr->locator_addr.sq_node = svc->node;
        pdr->locator_addr.sq_port = svc->port;

        pdr->locator_init_complete = true;
        mutex_unlock(&pdr->lock);

        /* Service pending lookup requests */
        schedule_work(&pdr->locator_work);

        return 0;
}

static void pdr_locator_del_server(struct qmi_handle *qmi,
                                   struct qmi_service *svc)
{
        struct pdr_handle *pdr = container_of(qmi, struct pdr_handle,
                                              locator_hdl);

        mutex_lock(&pdr->lock);
        pdr->locator_init_complete = false;

        pdr->locator_addr.sq_node = 0;
        pdr->locator_addr.sq_port = 0;
        mutex_unlock(&pdr->lock);
}

static const struct qmi_ops pdr_locator_ops = {
        .new_server = pdr_locator_new_server,
        .del_server = pdr_locator_del_server,
};

static int pdr_register_listener(struct pdr_handle *pdr,
                                 struct pdr_service *pds,
                                 bool enable)
{
        struct servreg_register_listener_resp resp;
        struct servreg_register_listener_req req;
        struct qmi_txn txn;
        int ret;

        ret = qmi_txn_init(&pdr->notifier_hdl, &txn,
                           servreg_register_listener_resp_ei,
                           &resp);
        if (ret < 0)
                return ret;

        req.enable = enable;
        strscpy(req.service_path, pds->service_path, sizeof(req.service_path));

        ret = qmi_send_request(&pdr->notifier_hdl, &pds->addr,
                               &txn, SERVREG_REGISTER_LISTENER_REQ,
                               SERVREG_REGISTER_LISTENER_REQ_LEN,
                               servreg_register_listener_req_ei,
                               &req);
        if (ret < 0) {
                qmi_txn_cancel(&txn);
                return ret;
        }

        ret = qmi_txn_wait(&txn, 5 * HZ);
        if (ret < 0) {
                pr_err("PDR: %s register listener txn wait failed: %d\n",
                       pds->service_path, ret);
                return ret;
        }

        if (resp.resp.result != QMI_RESULT_SUCCESS_V01) {
                pr_err("PDR: %s register listener failed: 0x%x\n",
                       pds->service_path, resp.resp.error);
                return -EREMOTEIO;
        }

        pds->state = resp.curr_state;

        return 0;
}

static void pdr_notifier_work(struct work_struct *work)
{
        struct pdr_handle *pdr = container_of(work, struct pdr_handle,
                                              notifier_work);
        struct pdr_service *pds;
        int ret;

        mutex_lock(&pdr->list_lock);
        list_for_each_entry(pds, &pdr->lookups, node) {
                if (pds->service_connected) {
                        if (!pds->need_notifier_register)
                                continue;

                        pds->need_notifier_register = false;
                        ret = pdr_register_listener(pdr, pds, true);
                        if (ret < 0)
                                pds->state = SERVREG_SERVICE_STATE_DOWN;
                } else {
                        if (!pds->need_notifier_remove)
                                continue;

                        pds->need_notifier_remove = false;
                        pds->state = SERVREG_SERVICE_STATE_DOWN;
                }

                mutex_lock(&pdr->status_lock);
                pdr->status(pds->state, pds->service_path, pdr->priv);
                mutex_unlock(&pdr->status_lock);
        }
        mutex_unlock(&pdr->list_lock);
}

static int pdr_notifier_new_server(struct qmi_handle *qmi,
                                   struct qmi_service *svc)
{
        struct pdr_handle *pdr = container_of(qmi, struct pdr_handle,
                                              notifier_hdl);
        struct pdr_service *pds;

        mutex_lock(&pdr->list_lock);
        list_for_each_entry(pds, &pdr->lookups, node) {
                if (pds->service == svc->service &&
                    pds->instance == svc->instance) {
                        pds->service_connected = true;
                        pds->need_notifier_register = true;
                        pds->addr.sq_family = AF_QIPCRTR;
                        pds->addr.sq_node = svc->node;
                        pds->addr.sq_port = svc->port;
                        queue_work(pdr->notifier_wq, &pdr->notifier_work);
                }
        }
        mutex_unlock(&pdr->list_lock);

        return 0;
}

static void pdr_notifier_del_server(struct qmi_handle *qmi,
                                    struct qmi_service *svc)
{
        struct pdr_handle *pdr = container_of(qmi, struct pdr_handle,
                                              notifier_hdl);
        struct pdr_service *pds;

        mutex_lock(&pdr->list_lock);
        list_for_each_entry(pds, &pdr->lookups, node) {
                if (pds->service == svc->service &&
                    pds->instance == svc->instance) {
                        pds->service_connected = false;
                        pds->need_notifier_remove = true;
                        pds->addr.sq_node = 0;
                        pds->addr.sq_port = 0;
                        queue_work(pdr->notifier_wq, &pdr->notifier_work);
                }
        }
        mutex_unlock(&pdr->list_lock);
}

static const struct qmi_ops pdr_notifier_ops = {
        .new_server = pdr_notifier_new_server,
        .del_server = pdr_notifier_del_server,
};

static int pdr_send_indack_msg(struct pdr_handle *pdr, struct pdr_service *pds,
                               u16 tid)
{
        struct servreg_set_ack_resp resp;
        struct servreg_set_ack_req req;
        struct qmi_txn txn;
        int ret;

        ret = qmi_txn_init(&pdr->notifier_hdl, &txn, servreg_set_ack_resp_ei,
                           &resp);
        if (ret < 0)
                return ret;

        req.transaction_id = tid;
        strscpy(req.service_path, pds->service_path, sizeof(req.service_path));

        ret = qmi_send_request(&pdr->notifier_hdl, &pds->addr,
                               &txn, SERVREG_SET_ACK_REQ,
                               SERVREG_SET_ACK_REQ_LEN,
                               servreg_set_ack_req_ei,
                               &req);

        /* Skip waiting for response */
        qmi_txn_cancel(&txn);
        return ret;
}

static void pdr_indack_work(struct work_struct *work)
{
        struct pdr_handle *pdr = container_of(work, struct pdr_handle,
                                              indack_work);
        struct pdr_list_node *ind, *tmp;
        struct pdr_service *pds;

        list_for_each_entry_safe(ind, tmp, &pdr->indack_list, node) {
                pds = ind->pds;

                mutex_lock(&pdr->status_lock);
                pds->state = ind->curr_state;
                pdr->status(pds->state, pds->service_path, pdr->priv);
                mutex_unlock(&pdr->status_lock);

                /* Ack the indication after clients release the PD resources */
                pdr_send_indack_msg(pdr, pds, ind->transaction_id);

                mutex_lock(&pdr->list_lock);
                list_del(&ind->node);
                mutex_unlock(&pdr->list_lock);

                kfree(ind);
        }
}

static void pdr_indication_cb(struct qmi_handle *qmi,
                              struct sockaddr_qrtr *sq,
                              struct qmi_txn *txn, const void *data)
{
        struct pdr_handle *pdr = container_of(qmi, struct pdr_handle,
                                              notifier_hdl);
        const struct servreg_state_updated_ind *ind_msg = data;
        struct pdr_list_node *ind;
        struct pdr_service *pds = NULL, *iter;

        if (!ind_msg || !ind_msg->service_path[0] ||
            strlen(ind_msg->service_path) > SERVREG_NAME_LENGTH)
                return;

        mutex_lock(&pdr->list_lock);
        list_for_each_entry(iter, &pdr->lookups, node) {
                if (strcmp(iter->service_path, ind_msg->service_path))
                        continue;

                pds = iter;
                break;
        }
        mutex_unlock(&pdr->list_lock);

        if (!pds)
                return;

        pr_info("PDR: Indication received from %s, state: 0x%x, trans-id: %d\n",
                ind_msg->service_path, ind_msg->curr_state,
                ind_msg->transaction_id);

        ind = kzalloc_obj(*ind);
        if (!ind)
                return;

        ind->transaction_id = ind_msg->transaction_id;
        ind->curr_state = ind_msg->curr_state;
        ind->pds = pds;

        mutex_lock(&pdr->list_lock);
        list_add_tail(&ind->node, &pdr->indack_list);
        mutex_unlock(&pdr->list_lock);

        queue_work(pdr->indack_wq, &pdr->indack_work);
}

static const struct qmi_msg_handler qmi_indication_handler[] = {
        {
                .type = QMI_INDICATION,
                .msg_id = SERVREG_STATE_UPDATED_IND_ID,
                .ei = servreg_state_updated_ind_ei,
                .decoded_size = sizeof(struct servreg_state_updated_ind),
                .fn = pdr_indication_cb,
        },
        {}
};

static int pdr_get_domain_list(struct servreg_get_domain_list_req *req,
                               struct servreg_get_domain_list_resp *resp,
                               struct pdr_handle *pdr)
{
        struct qmi_txn txn;
        int ret;

        ret = qmi_txn_init(&pdr->locator_hdl, &txn,
                           servreg_get_domain_list_resp_ei, resp);
        if (ret < 0)
                return ret;

        mutex_lock(&pdr->lock);
        ret = qmi_send_request(&pdr->locator_hdl,
                               &pdr->locator_addr,
                               &txn, SERVREG_GET_DOMAIN_LIST_REQ,
                               SERVREG_GET_DOMAIN_LIST_REQ_MAX_LEN,
                               servreg_get_domain_list_req_ei,
                               req);
        mutex_unlock(&pdr->lock);
        if (ret < 0) {
                qmi_txn_cancel(&txn);
                return ret;
        }

        ret = qmi_txn_wait(&txn, 5 * HZ);
        if (ret < 0) {
                pr_err("PDR: %s get domain list txn wait failed: %d\n",
                       req->service_name, ret);
                return ret;
        }

        if (resp->resp.result != QMI_RESULT_SUCCESS_V01) {
                pr_err("PDR: %s get domain list failed: 0x%x\n",
                       req->service_name, resp->resp.error);
                return -EREMOTEIO;
        }

        return 0;
}

static int pdr_locate_service(struct pdr_handle *pdr, struct pdr_service *pds)
{
        struct servreg_get_domain_list_req req;
        struct servreg_location_entry *entry;
        int domains_read = 0;
        int ret, i;

        struct servreg_get_domain_list_resp *resp __free(kfree) = kzalloc_obj(*resp);
        if (!resp)
                return -ENOMEM;

        /* Prepare req message */
        strscpy(req.service_name, pds->service_name, sizeof(req.service_name));
        req.domain_offset_valid = true;
        req.domain_offset = 0;

        do {
                req.domain_offset = domains_read;
                ret = pdr_get_domain_list(&req, resp, pdr);
                if (ret < 0)
                        return ret;

                for (i = 0; i < resp->domain_list_len; i++) {
                        entry = &resp->domain_list[i];

                        if (strnlen(entry->name, sizeof(entry->name)) == sizeof(entry->name))
                                continue;

                        if (!strcmp(entry->name, pds->service_path)) {
                                pds->service_data_valid = entry->service_data_valid;
                                pds->service_data = entry->service_data;
                                pds->instance = entry->instance;
                                return 0;
                        }
                }

                /* Update ret to indicate that the service is not yet found */
                ret = -ENXIO;

                /* Always read total_domains from the response msg */
                if (resp->domain_list_len > resp->total_domains)
                        resp->domain_list_len = resp->total_domains;

                domains_read += resp->domain_list_len;
        } while (domains_read < resp->total_domains);

        return ret;
}

static void pdr_notify_lookup_failure(struct pdr_handle *pdr,
                                      struct pdr_service *pds,
                                      int err)
{
        pr_err("PDR: service lookup for %s failed: %d\n",
               pds->service_name, err);

        if (err == -ENXIO)
                return;

        list_del(&pds->node);
        pds->state = SERVREG_LOCATOR_ERR;
        mutex_lock(&pdr->status_lock);
        pdr->status(pds->state, pds->service_path, pdr->priv);
        mutex_unlock(&pdr->status_lock);
        kfree(pds);
}

static void pdr_locator_work(struct work_struct *work)
{
        struct pdr_handle *pdr = container_of(work, struct pdr_handle,
                                              locator_work);
        struct pdr_service *pds, *tmp;
        int ret = 0;

        /* Bail out early if the SERVREG LOCATOR QMI service is not up */
        mutex_lock(&pdr->lock);
        if (!pdr->locator_init_complete) {
                mutex_unlock(&pdr->lock);
                pr_debug("PDR: SERVICE LOCATOR service not available\n");
                return;
        }
        mutex_unlock(&pdr->lock);

        mutex_lock(&pdr->list_lock);
        list_for_each_entry_safe(pds, tmp, &pdr->lookups, node) {
                if (!pds->need_locator_lookup)
                        continue;

                ret = pdr_locate_service(pdr, pds);
                if (ret < 0) {
                        pdr_notify_lookup_failure(pdr, pds, ret);
                        continue;
                }

                ret = qmi_add_lookup(&pdr->notifier_hdl, pds->service, 1,
                                     pds->instance);
                if (ret < 0) {
                        pdr_notify_lookup_failure(pdr, pds, ret);
                        continue;
                }

                pds->need_locator_lookup = false;
        }
        mutex_unlock(&pdr->list_lock);
}

/**
 * pdr_add_lookup() - register a tracking request for a PD
 * @pdr:                PDR client handle
 * @service_name:       service name of the tracking request
 * @service_path:       service path of the tracking request
 *
 * Registering a pdr lookup allows for tracking the life cycle of the PD.
 *
 * Return: pdr_service object on success, ERR_PTR on failure. -EALREADY is
 * returned if a lookup is already in progress for the given service path.
 */
struct pdr_service *pdr_add_lookup(struct pdr_handle *pdr,
                                   const char *service_name,
                                   const char *service_path)
{
        struct pdr_service *tmp;

        if (IS_ERR_OR_NULL(pdr))
                return ERR_PTR(-EINVAL);

        if (!service_name || strlen(service_name) > SERVREG_NAME_LENGTH ||
            !service_path || strlen(service_path) > SERVREG_NAME_LENGTH)
                return ERR_PTR(-EINVAL);

        struct pdr_service *pds __free(kfree) = kzalloc_obj(*pds);
        if (!pds)
                return ERR_PTR(-ENOMEM);

        pds->service = SERVREG_NOTIFIER_SERVICE;
        strscpy(pds->service_name, service_name, sizeof(pds->service_name));
        strscpy(pds->service_path, service_path, sizeof(pds->service_path));
        pds->need_locator_lookup = true;

        mutex_lock(&pdr->list_lock);
        list_for_each_entry(tmp, &pdr->lookups, node) {
                if (strcmp(tmp->service_path, service_path))
                        continue;

                mutex_unlock(&pdr->list_lock);
                return ERR_PTR(-EALREADY);
        }

        list_add(&pds->node, &pdr->lookups);
        mutex_unlock(&pdr->list_lock);

        schedule_work(&pdr->locator_work);

        return_ptr(pds);
}
EXPORT_SYMBOL_GPL(pdr_add_lookup);

/**
 * pdr_restart_pd() - restart PD
 * @pdr:        PDR client handle
 * @pds:        PD service handle
 *
 * Restarts the PD tracked by the PDR client handle for a given service path.
 *
 * Return: 0 on success, negative errno on failure.
 */
int pdr_restart_pd(struct pdr_handle *pdr, struct pdr_service *pds)
{
        struct servreg_restart_pd_resp resp;
        struct servreg_restart_pd_req req = { 0 };
        struct sockaddr_qrtr addr;
        struct pdr_service *tmp;
        struct qmi_txn txn;
        int ret;

        if (IS_ERR_OR_NULL(pdr) || IS_ERR_OR_NULL(pds))
                return -EINVAL;

        mutex_lock(&pdr->list_lock);
        list_for_each_entry(tmp, &pdr->lookups, node) {
                if (tmp != pds)
                        continue;

                if (!pds->service_connected)
                        break;

                /* Prepare req message */
                strscpy(req.service_path, pds->service_path, sizeof(req.service_path));
                addr = pds->addr;
                break;
        }
        mutex_unlock(&pdr->list_lock);

        if (!req.service_path[0])
                return -EINVAL;

        ret = qmi_txn_init(&pdr->notifier_hdl, &txn,
                           servreg_restart_pd_resp_ei,
                           &resp);
        if (ret < 0)
                return ret;

        ret = qmi_send_request(&pdr->notifier_hdl, &addr,
                               &txn, SERVREG_RESTART_PD_REQ,
                               SERVREG_RESTART_PD_REQ_MAX_LEN,
                               servreg_restart_pd_req_ei, &req);
        if (ret < 0) {
                qmi_txn_cancel(&txn);
                return ret;
        }

        ret = qmi_txn_wait(&txn, 5 * HZ);
        if (ret < 0) {
                pr_err("PDR: %s PD restart txn wait failed: %d\n",
                       req.service_path, ret);
                return ret;
        }

        /* Check response if PDR is disabled */
        if (resp.resp.result == QMI_RESULT_FAILURE_V01 &&
            resp.resp.error == QMI_ERR_DISABLED_V01) {
                pr_err("PDR: %s PD restart is disabled: 0x%x\n",
                       req.service_path, resp.resp.error);
                return -EOPNOTSUPP;
        }

        /* Check the response for other error case*/
        if (resp.resp.result != QMI_RESULT_SUCCESS_V01) {
                pr_err("PDR: %s request for PD restart failed: 0x%x\n",
                       req.service_path, resp.resp.error);
                return -EREMOTEIO;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(pdr_restart_pd);

/**
 * pdr_handle_alloc() - initialize the PDR client handle
 * @status:     function to be called on PD state change
 * @priv:       handle for client's use
 *
 * Initializes the PDR client handle to allow for tracking/restart of PDs.
 *
 * Return: pdr_handle object on success, ERR_PTR on failure.
 */
struct pdr_handle *pdr_handle_alloc(void (*status)(int state,
                                                   char *service_path,
                                                   void *priv), void *priv)
{
        int ret;

        if (!status)
                return ERR_PTR(-EINVAL);

        struct pdr_handle *pdr __free(kfree) = kzalloc_obj(*pdr);
        if (!pdr)
                return ERR_PTR(-ENOMEM);

        pdr->status = status;
        pdr->priv = priv;

        mutex_init(&pdr->status_lock);
        mutex_init(&pdr->list_lock);
        mutex_init(&pdr->lock);

        INIT_LIST_HEAD(&pdr->lookups);
        INIT_LIST_HEAD(&pdr->indack_list);

        INIT_WORK(&pdr->locator_work, pdr_locator_work);
        INIT_WORK(&pdr->notifier_work, pdr_notifier_work);
        INIT_WORK(&pdr->indack_work, pdr_indack_work);

        pdr->notifier_wq = create_singlethread_workqueue("pdr_notifier_wq");
        if (!pdr->notifier_wq)
                return ERR_PTR(-ENOMEM);

        pdr->indack_wq = alloc_ordered_workqueue("pdr_indack_wq", WQ_HIGHPRI);
        if (!pdr->indack_wq) {
                ret = -ENOMEM;
                goto destroy_notifier;
        }

        ret = qmi_handle_init(&pdr->locator_hdl,
                              SERVREG_GET_DOMAIN_LIST_RESP_MAX_LEN,
                              &pdr_locator_ops, NULL);
        if (ret < 0)
                goto destroy_indack;

        ret = qmi_add_lookup(&pdr->locator_hdl, SERVREG_LOCATOR_SERVICE, 1, 1);
        if (ret < 0)
                goto release_qmi_handle;

        ret = qmi_handle_init(&pdr->notifier_hdl,
                              SERVREG_STATE_UPDATED_IND_MAX_LEN,
                              &pdr_notifier_ops,
                              qmi_indication_handler);
        if (ret < 0)
                goto release_qmi_handle;

        return_ptr(pdr);

release_qmi_handle:
        qmi_handle_release(&pdr->locator_hdl);
destroy_indack:
        destroy_workqueue(pdr->indack_wq);
destroy_notifier:
        destroy_workqueue(pdr->notifier_wq);

        return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(pdr_handle_alloc);

/**
 * pdr_handle_release() - release the PDR client handle
 * @pdr:        PDR client handle
 *
 * Cleans up pending tracking requests and releases the underlying qmi handles.
 */
void pdr_handle_release(struct pdr_handle *pdr)
{
        struct pdr_service *pds, *tmp;

        if (IS_ERR_OR_NULL(pdr))
                return;

        mutex_lock(&pdr->list_lock);
        list_for_each_entry_safe(pds, tmp, &pdr->lookups, node) {
                list_del(&pds->node);
                kfree(pds);
        }
        mutex_unlock(&pdr->list_lock);

        cancel_work_sync(&pdr->locator_work);
        cancel_work_sync(&pdr->notifier_work);
        cancel_work_sync(&pdr->indack_work);

        destroy_workqueue(pdr->notifier_wq);
        destroy_workqueue(pdr->indack_wq);

        qmi_handle_release(&pdr->locator_hdl);
        qmi_handle_release(&pdr->notifier_hdl);

        kfree(pdr);
}
EXPORT_SYMBOL_GPL(pdr_handle_release);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Qualcomm Protection Domain Restart helpers");