// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2013-2018, The Linux Foundation. All rights reserved.
 * Copyright (C) 2018-2024 Linaro Ltd.
 */

#include <linux/qrtr.h>
#include <linux/string.h>
#include <linux/types.h>

#include "ipa.h"
#include "ipa_mem.h"
#include "ipa_modem.h"
#include "ipa_qmi_msg.h"

/**
 * DOC: AP/Modem QMI Handshake
 *
 * The AP and modem perform a "handshake" at initialization time to ensure
 * both sides know when everything is ready to begin operating.  The AP
 * driver (this code) uses two QMI handles (endpoints) for this; a client
 * using a service on the modem, and server to service modem requests (and
 * to supply an indication message from the AP).  Once the handshake is
 * complete, the AP and modem may begin IPA operation.  This occurs
 * only when the AP IPA driver, modem IPA driver, and IPA microcontroller
 * are ready.
 *
 * The QMI service on the modem expects to receive an INIT_DRIVER request from
 * the AP, which contains parameters used by the modem during initialization.
 * The AP sends this request as soon as it is knows the modem side service
 * is available.  The modem responds to this request, and if this response
 * contains a success result, the AP knows the modem IPA driver is ready.
 *
 * The modem is responsible for loading firmware on the IPA microcontroller.
 * This occurs only during the initial modem boot.  The modem sends a
 * separate DRIVER_INIT_COMPLETE request to the AP to report that the
 * microcontroller is ready.  The AP may assume the microcontroller is
 * ready and remain so (even if the modem reboots) once it has received
 * and responded to this request.
 *
 * There is one final exchange involved in the handshake.  It is required
 * on the initial modem boot, but optional (but in practice does occur) on
 * subsequent boots.  The modem expects to receive a final INIT_COMPLETE
 * indication message from the AP when it is about to begin its normal
 * operation.  The AP will only send this message after it has received
 * and responded to an INDICATION_REGISTER request from the modem.
 *
 * So in summary:
 * - Whenever the AP learns the modem has booted and its IPA QMI service
 *   is available, it sends an INIT_DRIVER request to the modem.  The
 *   modem supplies a success response when it is ready to operate.
 * - On the initial boot, the modem sets up the IPA microcontroller, and
 *   sends a DRIVER_INIT_COMPLETE request to the AP when this is done.
 * - When the modem is ready to receive an INIT_COMPLETE indication from
 *   the AP, it sends an INDICATION_REGISTER request to the AP.
 * - On the initial modem boot, everything is ready when:
 *      - AP has received a success response from its INIT_DRIVER request
 *      - AP has responded to a DRIVER_INIT_COMPLETE request
 *      - AP has responded to an INDICATION_REGISTER request from the modem
 *      - AP has sent an INIT_COMPLETE indication to the modem
 * - On subsequent modem boots, everything is ready when:
 *      - AP has received a success response from its INIT_DRIVER request
 *      - AP has responded to a DRIVER_INIT_COMPLETE request
 * - The INDICATION_REGISTER request and INIT_COMPLETE indication are
 *   optional for non-initial modem boots, and have no bearing on the
 *   determination of when things are "ready"
 */

#define IPA_HOST_SERVICE_SVC_ID         0x31
#define IPA_HOST_SVC_VERS               1
#define IPA_HOST_SERVICE_INS_ID         1

#define IPA_MODEM_SERVICE_SVC_ID        0x31
#define IPA_MODEM_SERVICE_INS_ID        2
#define IPA_MODEM_SVC_VERS              1

#define QMI_INIT_DRIVER_TIMEOUT         60000   /* A minute in milliseconds */

/* Send an INIT_COMPLETE indication message to the modem */
static void ipa_server_init_complete(struct ipa_qmi *ipa_qmi)
{
        struct ipa *ipa = container_of(ipa_qmi, struct ipa, qmi);
        struct qmi_handle *qmi = &ipa_qmi->server_handle;
        struct sockaddr_qrtr *sq = &ipa_qmi->modem_sq;
        struct ipa_init_complete_ind ind = { };
        int ret;

        ind.status.result = QMI_RESULT_SUCCESS_V01;
        ind.status.error = QMI_ERR_NONE_V01;

        ret = qmi_send_indication(qmi, sq, IPA_QMI_INIT_COMPLETE,
                                   IPA_QMI_INIT_COMPLETE_IND_SZ,
                                   ipa_init_complete_ind_ei, &ind);
        if (ret)
                dev_err(ipa->dev,
                        "error %d sending init complete indication\n", ret);
        else
                ipa_qmi->indication_sent = true;
}

/* If requested (and not already sent) send the INIT_COMPLETE indication */
static void ipa_qmi_indication(struct ipa_qmi *ipa_qmi)
{
        if (!ipa_qmi->indication_requested)
                return;

        if (ipa_qmi->indication_sent)
                return;

        ipa_server_init_complete(ipa_qmi);
}

/* Determine whether everything is ready to start normal operation.
 * We know everything (else) is ready when we know the IPA driver on
 * the modem is ready, and the microcontroller is ready.
 *
 * When the modem boots (or reboots), the handshake sequence starts
 * with the AP sending the modem an INIT_DRIVER request.  Within
 * that request, the uc_loaded flag will be zero (false) for an
 * initial boot, non-zero (true) for a subsequent (SSR) boot.
 */
static void ipa_qmi_ready(struct ipa_qmi *ipa_qmi)
{
        struct ipa *ipa;
        int ret;

        /* We aren't ready until the modem and microcontroller are */
        if (!ipa_qmi->modem_ready || !ipa_qmi->uc_ready)
                return;

        /* Send the indication message if it was requested */
        ipa_qmi_indication(ipa_qmi);

        /* The initial boot requires us to send the indication. */
        if (ipa_qmi->initial_boot) {
                if (!ipa_qmi->indication_sent)
                        return;

                /* The initial modem boot completed successfully */
                ipa_qmi->initial_boot = false;
        }

        /* We're ready.  Start up normal operation */
        ipa = container_of(ipa_qmi, struct ipa, qmi);
        ret = ipa_modem_start(ipa);
        if (ret)
                dev_err(ipa->dev, "error %d starting modem\n", ret);
}

/* All QMI clients from the modem node are gone (modem shut down or crashed). */
static void ipa_server_bye(struct qmi_handle *qmi, unsigned int node)
{
        struct ipa_qmi *ipa_qmi;

        ipa_qmi = container_of(qmi, struct ipa_qmi, server_handle);

        /* The modem client and server go away at the same time */
        memset(&ipa_qmi->modem_sq, 0, sizeof(ipa_qmi->modem_sq));

        /* initial_boot doesn't change when modem reboots */
        /* uc_ready doesn't change when modem reboots */
        ipa_qmi->modem_ready = false;
        ipa_qmi->indication_requested = false;
        ipa_qmi->indication_sent = false;
}

static const struct qmi_ops ipa_server_ops = {
        .bye            = ipa_server_bye,
};

/* Callback function to handle an INDICATION_REGISTER request message from the
 * modem.  This informs the AP that the modem is now ready to receive the
 * INIT_COMPLETE indication message.
 */
static void ipa_server_indication_register(struct qmi_handle *qmi,
                                           struct sockaddr_qrtr *sq,
                                           struct qmi_txn *txn,
                                           const void *decoded)
{
        struct ipa_indication_register_rsp rsp = { };
        struct ipa_qmi *ipa_qmi;
        struct ipa *ipa;
        int ret;

        ipa_qmi = container_of(qmi, struct ipa_qmi, server_handle);
        ipa = container_of(ipa_qmi, struct ipa, qmi);

        rsp.rsp.result = QMI_RESULT_SUCCESS_V01;
        rsp.rsp.error = QMI_ERR_NONE_V01;

        ret = qmi_send_response(qmi, sq, txn, IPA_QMI_INDICATION_REGISTER,
                                IPA_QMI_INDICATION_REGISTER_RSP_SZ,
                                ipa_indication_register_rsp_ei, &rsp);
        if (!ret) {
                ipa_qmi->indication_requested = true;
                ipa_qmi_ready(ipa_qmi);         /* We might be ready now */
        } else {
                dev_err(ipa->dev,
                        "error %d sending register indication response\n", ret);
        }
}

/* Respond to a DRIVER_INIT_COMPLETE request message from the modem. */
static void ipa_server_driver_init_complete(struct qmi_handle *qmi,
                                            struct sockaddr_qrtr *sq,
                                            struct qmi_txn *txn,
                                            const void *decoded)
{
        struct ipa_driver_init_complete_rsp rsp = { };
        struct ipa_qmi *ipa_qmi;
        struct ipa *ipa;
        int ret;

        ipa_qmi = container_of(qmi, struct ipa_qmi, server_handle);
        ipa = container_of(ipa_qmi, struct ipa, qmi);

        rsp.rsp.result = QMI_RESULT_SUCCESS_V01;
        rsp.rsp.error = QMI_ERR_NONE_V01;

        ret = qmi_send_response(qmi, sq, txn, IPA_QMI_DRIVER_INIT_COMPLETE,
                                IPA_QMI_DRIVER_INIT_COMPLETE_RSP_SZ,
                                ipa_driver_init_complete_rsp_ei, &rsp);
        if (!ret) {
                ipa_qmi->uc_ready = true;
                ipa_qmi_ready(ipa_qmi);         /* We might be ready now */
        } else {
                dev_err(ipa->dev,
                        "error %d sending init complete response\n", ret);
        }
}

/* The server handles two request message types sent by the modem. */
static const struct qmi_msg_handler ipa_server_msg_handlers[] = {
        {
                .type           = QMI_REQUEST,
                .msg_id         = IPA_QMI_INDICATION_REGISTER,
                .ei             = ipa_indication_register_req_ei,
                .decoded_size   = IPA_QMI_INDICATION_REGISTER_REQ_SZ,
                .fn             = ipa_server_indication_register,
        },
        {
                .type           = QMI_REQUEST,
                .msg_id         = IPA_QMI_DRIVER_INIT_COMPLETE,
                .ei             = ipa_driver_init_complete_req_ei,
                .decoded_size   = IPA_QMI_DRIVER_INIT_COMPLETE_REQ_SZ,
                .fn             = ipa_server_driver_init_complete,
        },
        { },
};

/* Handle an INIT_DRIVER response message from the modem. */
static void ipa_client_init_driver(struct qmi_handle *qmi,
                                   struct sockaddr_qrtr *sq,
                                   struct qmi_txn *txn, const void *decoded)
{
        txn->result = 0;        /* IPA_QMI_INIT_DRIVER request was successful */
        complete(&txn->completion);
}

/* The client handles one response message type sent by the modem. */
static const struct qmi_msg_handler ipa_client_msg_handlers[] = {
        {
                .type           = QMI_RESPONSE,
                .msg_id         = IPA_QMI_INIT_DRIVER,
                .ei             = ipa_init_modem_driver_rsp_ei,
                .decoded_size   = IPA_QMI_INIT_DRIVER_RSP_SZ,
                .fn             = ipa_client_init_driver,
        },
        { },
};

/* Return a pointer to an init modem driver request structure, which contains
 * configuration parameters for the modem.  The modem may be started multiple
 * times, but generally these parameters don't change so we can reuse the
 * request structure once it's initialized.  The only exception is the
 * skip_uc_load field, which will be set only after the microcontroller has
 * reported it has completed its initialization.
 */
static const struct ipa_init_modem_driver_req *
init_modem_driver_req(struct ipa_qmi *ipa_qmi)
{
        struct ipa *ipa = container_of(ipa_qmi, struct ipa, qmi);
        u32 modem_route_count = ipa->modem_route_count;
        static struct ipa_init_modem_driver_req req;
        const struct ipa_mem *mem;

        /* The microcontroller is initialized on the first boot */
        req.skip_uc_load_valid = 1;
        req.skip_uc_load = ipa->uc_loaded ? 1 : 0;

        /* We only have to initialize most of it once */
        if (req.platform_type_valid)
                return &req;

        req.platform_type_valid = 1;
        req.platform_type = IPA_QMI_PLATFORM_TYPE_MSM_ANDROID;

        mem = ipa_mem_find(ipa, IPA_MEM_MODEM_HEADER);
        if (mem->size) {
                req.hdr_tbl_info_valid = 1;
                req.hdr_tbl_info.start = ipa->mem_offset + mem->offset;
                req.hdr_tbl_info.end = req.hdr_tbl_info.start + mem->size - 1;
        }

        mem = ipa_mem_find(ipa, IPA_MEM_V4_ROUTE);
        req.v4_route_tbl_info_valid = 1;
        req.v4_route_tbl_info.start = ipa->mem_offset + mem->offset;
        req.v4_route_tbl_info.end = modem_route_count - 1;

        mem = ipa_mem_find(ipa, IPA_MEM_V6_ROUTE);
        req.v6_route_tbl_info_valid = 1;
        req.v6_route_tbl_info.start = ipa->mem_offset + mem->offset;
        req.v6_route_tbl_info.end = modem_route_count - 1;

        mem = ipa_mem_find(ipa, IPA_MEM_V4_FILTER);
        req.v4_filter_tbl_start_valid = 1;
        req.v4_filter_tbl_start = ipa->mem_offset + mem->offset;

        mem = ipa_mem_find(ipa, IPA_MEM_V6_FILTER);
        req.v6_filter_tbl_start_valid = 1;
        req.v6_filter_tbl_start = ipa->mem_offset + mem->offset;

        mem = ipa_mem_find(ipa, IPA_MEM_MODEM);
        if (mem->size) {
                req.modem_mem_info_valid = 1;
                req.modem_mem_info.start = ipa->mem_offset + mem->offset;
                req.modem_mem_info.size = mem->size;
        }

        req.ctrl_comm_dest_end_pt_valid = 1;
        req.ctrl_comm_dest_end_pt =
                ipa->name_map[IPA_ENDPOINT_AP_MODEM_RX]->endpoint_id;

        /* skip_uc_load_valid and skip_uc_load are set above */

        mem = ipa_mem_find(ipa, IPA_MEM_MODEM_PROC_CTX);
        if (mem->size) {
                req.hdr_proc_ctx_tbl_info_valid = 1;
                req.hdr_proc_ctx_tbl_info.start =
                        ipa->mem_offset + mem->offset;
                req.hdr_proc_ctx_tbl_info.end =
                        req.hdr_proc_ctx_tbl_info.start + mem->size - 1;
        }

        /* Nothing to report for the compression table (zip_tbl_info) */

        mem = ipa_mem_find(ipa, IPA_MEM_V4_ROUTE_HASHED);
        if (mem->size) {
                req.v4_hash_route_tbl_info_valid = 1;
                req.v4_hash_route_tbl_info.start =
                                ipa->mem_offset + mem->offset;
                req.v4_hash_route_tbl_info.end = modem_route_count - 1;
        }

        mem = ipa_mem_find(ipa, IPA_MEM_V6_ROUTE_HASHED);
        if (mem->size) {
                req.v6_hash_route_tbl_info_valid = 1;
                req.v6_hash_route_tbl_info.start =
                        ipa->mem_offset + mem->offset;
                req.v6_hash_route_tbl_info.end = modem_route_count - 1;
        }

        mem = ipa_mem_find(ipa, IPA_MEM_V4_FILTER_HASHED);
        if (mem->size) {
                req.v4_hash_filter_tbl_start_valid = 1;
                req.v4_hash_filter_tbl_start = ipa->mem_offset + mem->offset;
        }

        mem = ipa_mem_find(ipa, IPA_MEM_V6_FILTER_HASHED);
        if (mem->size) {
                req.v6_hash_filter_tbl_start_valid = 1;
                req.v6_hash_filter_tbl_start = ipa->mem_offset + mem->offset;
        }

        /* The stats fields are only valid for IPA v4.0+ */
        if (ipa->version >= IPA_VERSION_4_0) {
                mem = ipa_mem_find(ipa, IPA_MEM_STATS_QUOTA_MODEM);
                if (mem->size) {
                        req.hw_stats_quota_base_addr_valid = 1;
                        req.hw_stats_quota_base_addr =
                                ipa->mem_offset + mem->offset;
                        req.hw_stats_quota_size_valid = 1;
                        req.hw_stats_quota_size = ipa->mem_offset + mem->size;
                }

                /* If the DROP stats region is defined, include it */
                mem = ipa_mem_find(ipa, IPA_MEM_STATS_DROP);
                if (mem && mem->size) {
                        req.hw_stats_drop_base_addr_valid = 1;
                        req.hw_stats_drop_base_addr =
                                ipa->mem_offset + mem->offset;
                        req.hw_stats_drop_size_valid = 1;
                        req.hw_stats_drop_size = ipa->mem_offset + mem->size;
                }
        }

        return &req;
}

/* Send an INIT_DRIVER request to the modem, and wait for it to complete. */
static void ipa_client_init_driver_work(struct work_struct *work)
{
        unsigned long timeout = msecs_to_jiffies(QMI_INIT_DRIVER_TIMEOUT);
        const struct ipa_init_modem_driver_req *req;
        struct ipa_qmi *ipa_qmi;
        struct qmi_handle *qmi;
        struct qmi_txn txn;
        struct device *dev;
        struct ipa *ipa;
        int ret;

        ipa_qmi = container_of(work, struct ipa_qmi, init_driver_work);
        qmi = &ipa_qmi->client_handle;

        ipa = container_of(ipa_qmi, struct ipa, qmi);
        dev = ipa->dev;

        ret = qmi_txn_init(qmi, &txn, NULL, NULL);
        if (ret < 0) {
                dev_err(dev, "error %d preparing init driver request\n", ret);
                return;
        }

        /* Send the request, and if successful wait for its response */
        req = init_modem_driver_req(ipa_qmi);
        ret = qmi_send_request(qmi, &ipa_qmi->modem_sq, &txn,
                               IPA_QMI_INIT_DRIVER, IPA_QMI_INIT_DRIVER_REQ_SZ,
                               ipa_init_modem_driver_req_ei, req);
        if (ret)
                dev_err(dev, "error %d sending init driver request\n", ret);
        else if ((ret = qmi_txn_wait(&txn, timeout)))
                dev_err(dev, "error %d awaiting init driver response\n", ret);

        if (!ret) {
                ipa_qmi->modem_ready = true;
                ipa_qmi_ready(ipa_qmi);         /* We might be ready now */
        } else {
                /* If any error occurs we need to cancel the transaction */
                qmi_txn_cancel(&txn);
        }
}

/* The modem server is now available.  We will send an INIT_DRIVER request
 * to the modem, but can't wait for it to complete in this callback thread.
 * Schedule a worker on the global workqueue to do that for us.
 */
static int
ipa_client_new_server(struct qmi_handle *qmi, struct qmi_service *svc)
{
        struct ipa_qmi *ipa_qmi;

        ipa_qmi = container_of(qmi, struct ipa_qmi, client_handle);

        ipa_qmi->modem_sq.sq_family = AF_QIPCRTR;
        ipa_qmi->modem_sq.sq_node = svc->node;
        ipa_qmi->modem_sq.sq_port = svc->port;

        schedule_work(&ipa_qmi->init_driver_work);

        return 0;
}

static const struct qmi_ops ipa_client_ops = {
        .new_server     = ipa_client_new_server,
};

/* Set up for QMI message exchange */
int ipa_qmi_setup(struct ipa *ipa)
{
        struct ipa_qmi *ipa_qmi = &ipa->qmi;
        int ret;

        ipa_qmi->initial_boot = true;

        /* The server handle is used to handle the DRIVER_INIT_COMPLETE
         * request on the first modem boot.  It also receives the
         * INDICATION_REGISTER request on the first boot and (optionally)
         * subsequent boots.  The INIT_COMPLETE indication message is
         * sent over the server handle if requested.
         */
        ret = qmi_handle_init(&ipa_qmi->server_handle,
                              IPA_QMI_SERVER_MAX_RCV_SZ, &ipa_server_ops,
                              ipa_server_msg_handlers);
        if (ret)
                return ret;

        ret = qmi_add_server(&ipa_qmi->server_handle, IPA_HOST_SERVICE_SVC_ID,
                             IPA_HOST_SVC_VERS, IPA_HOST_SERVICE_INS_ID);
        if (ret)
                goto err_server_handle_release;

        /* The client handle is only used for sending an INIT_DRIVER request
         * to the modem, and receiving its response message.
         */
        ret = qmi_handle_init(&ipa_qmi->client_handle,
                              IPA_QMI_CLIENT_MAX_RCV_SZ, &ipa_client_ops,
                              ipa_client_msg_handlers);
        if (ret)
                goto err_server_handle_release;

        /* We need this ready before the service lookup is added */
        INIT_WORK(&ipa_qmi->init_driver_work, ipa_client_init_driver_work);

        ret = qmi_add_lookup(&ipa_qmi->client_handle, IPA_MODEM_SERVICE_SVC_ID,
                             IPA_MODEM_SVC_VERS, IPA_MODEM_SERVICE_INS_ID);
        if (ret)
                goto err_client_handle_release;

        return 0;

err_client_handle_release:
        /* Releasing the handle also removes registered lookups */
        qmi_handle_release(&ipa_qmi->client_handle);
        memset(&ipa_qmi->client_handle, 0, sizeof(ipa_qmi->client_handle));
err_server_handle_release:
        /* Releasing the handle also removes registered services */
        qmi_handle_release(&ipa_qmi->server_handle);
        memset(&ipa_qmi->server_handle, 0, sizeof(ipa_qmi->server_handle));

        return ret;
}

/* Tear down IPA QMI handles */
void ipa_qmi_teardown(struct ipa *ipa)
{
        cancel_work_sync(&ipa->qmi.init_driver_work);

        qmi_handle_release(&ipa->qmi.client_handle);
        memset(&ipa->qmi.client_handle, 0, sizeof(ipa->qmi.client_handle));

        qmi_handle_release(&ipa->qmi.server_handle);
        memset(&ipa->qmi.server_handle, 0, sizeof(ipa->qmi.server_handle));
}