/*
 *
 * Intel Management Engine Interface (Intel MEI) Linux driver
 * Copyright (c) 2003-2012, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 */

#include <linux/pci.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/mei.h>

#include "mei_dev.h"
#include "hbm.h"
#include "hw-me.h"

/**
 * mei_hbm_me_cl_allocate - allocates storage for me clients
 *
 * @dev: the device structure
 *
 * returns none.
 */
static void mei_hbm_me_cl_allocate(struct mei_device *dev)
{
        struct mei_me_client *clients;
        int b;

        /* count how many ME clients we have */
        for_each_set_bit(b, dev->me_clients_map, MEI_CLIENTS_MAX)
                dev->me_clients_num++;

        if (dev->me_clients_num <= 0)
                return;

        kfree(dev->me_clients);
        dev->me_clients = NULL;

        dev_dbg(&dev->pdev->dev, "memory allocation for ME clients size=%zd.\n",
                dev->me_clients_num * sizeof(struct mei_me_client));
        /* allocate storage for ME clients representation */
        clients = kcalloc(dev->me_clients_num,
                        sizeof(struct mei_me_client), GFP_KERNEL);
        if (!clients) {
                dev_err(&dev->pdev->dev, "memory allocation for ME clients failed.\n");
                dev->dev_state = MEI_DEV_RESETTING;
                mei_reset(dev, 1);
                return;
        }
        dev->me_clients = clients;
        return;
}

/**
 * mei_hbm_cl_hdr - construct client hbm header
 *
 * @cl: - client
 * @hbm_cmd: host bus message command
 * @buf: buffer for cl header
 * @len: buffer length
 */
static inline
void mei_hbm_cl_hdr(struct mei_cl *cl, u8 hbm_cmd, void *buf, size_t len)
{
        struct mei_hbm_cl_cmd *cmd = buf;

        memset(cmd, 0, len);

        cmd->hbm_cmd = hbm_cmd;
        cmd->host_addr = cl->host_client_id;
        cmd->me_addr = cl->me_client_id;
}

/**
 * same_disconn_addr - tells if they have the same address
 *
 * @file: private data of the file object.
 * @disconn: disconnection request.
 *
 * returns true if addres are same
 */
static inline
bool mei_hbm_cl_addr_equal(struct mei_cl *cl, void *buf)
{
        struct mei_hbm_cl_cmd *cmd = buf;
        return cl->host_client_id == cmd->host_addr &&
                cl->me_client_id == cmd->me_addr;
}


/**
 * is_treat_specially_client - checks if the message belongs
 * to the file private data.
 *
 * @cl: private data of the file object
 * @rs: connect response bus message
 *
 */
static bool is_treat_specially_client(struct mei_cl *cl,
                struct hbm_client_connect_response *rs)
{
        if (mei_hbm_cl_addr_equal(cl, rs)) {
                if (!rs->status) {
                        cl->state = MEI_FILE_CONNECTED;
                        cl->status = 0;

                } else {
                        cl->state = MEI_FILE_DISCONNECTED;
                        cl->status = -ENODEV;
                }
                cl->timer_count = 0;

                return true;
        }
        return false;
}

int mei_hbm_start_wait(struct mei_device *dev)
{
        int ret;
        if (dev->hbm_state > MEI_HBM_START)
                return 0;

        mutex_unlock(&dev->device_lock);
        ret = wait_event_interruptible_timeout(dev->wait_recvd_msg,
                        dev->hbm_state == MEI_HBM_IDLE ||
                        dev->hbm_state > MEI_HBM_START,
                        mei_secs_to_jiffies(MEI_INTEROP_TIMEOUT));
        mutex_lock(&dev->device_lock);

        if (ret <= 0 && (dev->hbm_state <= MEI_HBM_START)) {
                dev->hbm_state = MEI_HBM_IDLE;
                dev_err(&dev->pdev->dev, "waiting for mei start failed\n");
                return -ETIMEDOUT;
        }
        return 0;
}

/**
 * mei_hbm_start_req - sends start request message.
 *
 * @dev: the device structure
 */
int mei_hbm_start_req(struct mei_device *dev)
{
        struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
        struct hbm_host_version_request *start_req;
        const size_t len = sizeof(struct hbm_host_version_request);

        mei_hbm_hdr(mei_hdr, len);

        /* host start message */
        start_req = (struct hbm_host_version_request *)dev->wr_msg.data;
        memset(start_req, 0, len);
        start_req->hbm_cmd = HOST_START_REQ_CMD;
        start_req->host_version.major_version = HBM_MAJOR_VERSION;
        start_req->host_version.minor_version = HBM_MINOR_VERSION;

        dev->hbm_state = MEI_HBM_IDLE;
        if (mei_write_message(dev, mei_hdr, dev->wr_msg.data)) {
                dev_err(&dev->pdev->dev, "version message write failed\n");
                dev->dev_state = MEI_DEV_RESETTING;
                mei_reset(dev, 1);
                return -ENODEV;
        }
        dev->hbm_state = MEI_HBM_START;
        dev->init_clients_timer = MEI_CLIENTS_INIT_TIMEOUT;
        return 0;
}

/*
 * mei_hbm_enum_clients_req - sends enumeration client request message.
 *
 * @dev: the device structure
 *
 * returns none.
 */
static void mei_hbm_enum_clients_req(struct mei_device *dev)
{
        struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
        struct hbm_host_enum_request *enum_req;
        const size_t len = sizeof(struct hbm_host_enum_request);
        /* enumerate clients */
        mei_hbm_hdr(mei_hdr, len);

        enum_req = (struct hbm_host_enum_request *)dev->wr_msg.data;
        memset(enum_req, 0, len);
        enum_req->hbm_cmd = HOST_ENUM_REQ_CMD;

        if (mei_write_message(dev, mei_hdr, dev->wr_msg.data)) {
                dev->dev_state = MEI_DEV_RESETTING;
                dev_err(&dev->pdev->dev, "enumeration request write failed.\n");
                mei_reset(dev, 1);
        }
        dev->hbm_state = MEI_HBM_ENUM_CLIENTS;
        dev->init_clients_timer = MEI_CLIENTS_INIT_TIMEOUT;
        return;
}

/**
 * mei_hbm_prop_req - request property for a single client
 *
 * @dev: the device structure
 *
 * returns none.
 */

static int mei_hbm_prop_req(struct mei_device *dev)
{

        struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
        struct hbm_props_request *prop_req;
        const size_t len = sizeof(struct hbm_props_request);
        unsigned long next_client_index;
        u8 client_num;


        client_num = dev->me_client_presentation_num;

        next_client_index = find_next_bit(dev->me_clients_map, MEI_CLIENTS_MAX,
                                          dev->me_client_index);

        /* We got all client properties */
        if (next_client_index == MEI_CLIENTS_MAX) {
                dev->hbm_state = MEI_HBM_STARTED;
                schedule_work(&dev->init_work);

                return 0;
        }

        dev->me_clients[client_num].client_id = next_client_index;
        dev->me_clients[client_num].mei_flow_ctrl_creds = 0;

        mei_hbm_hdr(mei_hdr, len);
        prop_req = (struct hbm_props_request *)dev->wr_msg.data;

        memset(prop_req, 0, sizeof(struct hbm_props_request));


        prop_req->hbm_cmd = HOST_CLIENT_PROPERTIES_REQ_CMD;
        prop_req->address = next_client_index;

        if (mei_write_message(dev, mei_hdr, dev->wr_msg.data)) {
                dev->dev_state = MEI_DEV_RESETTING;
                dev_err(&dev->pdev->dev, "properties request write failed\n");
                mei_reset(dev, 1);

                return -EIO;
        }

        dev->init_clients_timer = MEI_CLIENTS_INIT_TIMEOUT;
        dev->me_client_index = next_client_index;

        return 0;
}

/**
 * mei_hbm_stop_req_prepare - perpare stop request message
 *
 * @dev - mei device
 * @mei_hdr - mei message header
 * @data - hbm message body buffer
 */
static void mei_hbm_stop_req_prepare(struct mei_device *dev,
                struct mei_msg_hdr *mei_hdr, unsigned char *data)
{
        struct hbm_host_stop_request *req =
                        (struct hbm_host_stop_request *)data;
        const size_t len = sizeof(struct hbm_host_stop_request);

        mei_hbm_hdr(mei_hdr, len);

        memset(req, 0, len);
        req->hbm_cmd = HOST_STOP_REQ_CMD;
        req->reason = DRIVER_STOP_REQUEST;
}

/**
 * mei_hbm_cl_flow_control_req - sends flow control requst.
 *
 * @dev: the device structure
 * @cl: client info
 *
 * This function returns -EIO on write failure
 */
int mei_hbm_cl_flow_control_req(struct mei_device *dev, struct mei_cl *cl)
{
        struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
        const size_t len = sizeof(struct hbm_flow_control);

        mei_hbm_hdr(mei_hdr, len);
        mei_hbm_cl_hdr(cl, MEI_FLOW_CONTROL_CMD, dev->wr_msg.data, len);

        dev_dbg(&dev->pdev->dev, "sending flow control host client = %d, ME client = %d\n",
                cl->host_client_id, cl->me_client_id);

        return mei_write_message(dev, mei_hdr, dev->wr_msg.data);
}

/**
 * mei_hbm_add_single_flow_creds - adds single buffer credentials.
 *
 * @dev: the device structure
 * @flow: flow control.
 */
static void mei_hbm_add_single_flow_creds(struct mei_device *dev,
                                  struct hbm_flow_control *flow)
{
        struct mei_me_client *client;
        int i;

        for (i = 0; i < dev->me_clients_num; i++) {
                client = &dev->me_clients[i];
                if (client && flow->me_addr == client->client_id) {
                        if (client->props.single_recv_buf) {
                                client->mei_flow_ctrl_creds++;
                                dev_dbg(&dev->pdev->dev, "recv flow ctrl msg ME %d (single).\n",
                                    flow->me_addr);
                                dev_dbg(&dev->pdev->dev, "flow control credentials =%d.\n",
                                    client->mei_flow_ctrl_creds);
                        } else {
                                BUG();  /* error in flow control */
                        }
                }
        }
}

/**
 * mei_hbm_cl_flow_control_res - flow control response from me
 *
 * @dev: the device structure
 * @flow_control: flow control response bus message
 */
static void mei_hbm_cl_flow_control_res(struct mei_device *dev,
                struct hbm_flow_control *flow_control)
{
        struct mei_cl *cl = NULL;
        struct mei_cl *next = NULL;

        if (!flow_control->host_addr) {
                /* single receive buffer */
                mei_hbm_add_single_flow_creds(dev, flow_control);
                return;
        }

        /* normal connection */
        list_for_each_entry_safe(cl, next, &dev->file_list, link) {
                if (mei_hbm_cl_addr_equal(cl, flow_control)) {
                        cl->mei_flow_ctrl_creds++;
                        dev_dbg(&dev->pdev->dev, "flow ctrl msg for host %d ME %d.\n",
                                flow_control->host_addr, flow_control->me_addr);
                        dev_dbg(&dev->pdev->dev, "flow control credentials = %d.\n",
                                    cl->mei_flow_ctrl_creds);
                                break;
                }
        }
}


/**
 * mei_hbm_cl_disconnect_req - sends disconnect message to fw.
 *
 * @dev: the device structure
 * @cl: a client to disconnect from
 *
 * This function returns -EIO on write failure
 */
int mei_hbm_cl_disconnect_req(struct mei_device *dev, struct mei_cl *cl)
{
        struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
        const size_t len = sizeof(struct hbm_client_connect_request);

        mei_hbm_hdr(mei_hdr, len);
        mei_hbm_cl_hdr(cl, CLIENT_DISCONNECT_REQ_CMD, dev->wr_msg.data, len);

        return mei_write_message(dev, mei_hdr, dev->wr_msg.data);
}

/**
 * mei_hbm_cl_disconnect_res - disconnect response from ME
 *
 * @dev: the device structure
 * @rs: disconnect response bus message
 */
static void mei_hbm_cl_disconnect_res(struct mei_device *dev,
                struct hbm_client_connect_response *rs)
{
        struct mei_cl *cl;
        struct mei_cl_cb *pos = NULL, *next = NULL;

        dev_dbg(&dev->pdev->dev,
                        "disconnect_response:\n"
                        "ME Client = %d\n"
                        "Host Client = %d\n"
                        "Status = %d\n",
                        rs->me_addr,
                        rs->host_addr,
                        rs->status);

        list_for_each_entry_safe(pos, next, &dev->ctrl_rd_list.list, list) {
                cl = pos->cl;

                if (!cl) {
                        list_del(&pos->list);
                        return;
                }

                dev_dbg(&dev->pdev->dev, "list_for_each_entry_safe in ctrl_rd_list.\n");
                if (mei_hbm_cl_addr_equal(cl, rs)) {
                        list_del(&pos->list);
                        if (!rs->status)
                                cl->state = MEI_FILE_DISCONNECTED;

                        cl->status = 0;
                        cl->timer_count = 0;
                        break;
                }
        }
}

/**
 * mei_hbm_cl_connect_req - send connection request to specific me client
 *
 * @dev: the device structure
 * @cl: a client to connect to
 *
 * returns -EIO on write failure
 */
int mei_hbm_cl_connect_req(struct mei_device *dev, struct mei_cl *cl)
{
        struct mei_msg_hdr *mei_hdr = &dev->wr_msg.hdr;
        const size_t len = sizeof(struct hbm_client_connect_request);

        mei_hbm_hdr(mei_hdr, len);
        mei_hbm_cl_hdr(cl, CLIENT_CONNECT_REQ_CMD, dev->wr_msg.data, len);

        return mei_write_message(dev, mei_hdr,  dev->wr_msg.data);
}

/**
 * mei_hbm_cl_connect_res - connect resposne from the ME
 *
 * @dev: the device structure
 * @rs: connect response bus message
 */
static void mei_hbm_cl_connect_res(struct mei_device *dev,
                struct hbm_client_connect_response *rs)
{

        struct mei_cl *cl;
        struct mei_cl_cb *pos = NULL, *next = NULL;

        dev_dbg(&dev->pdev->dev,
                        "connect_response:\n"
                        "ME Client = %d\n"
                        "Host Client = %d\n"
                        "Status = %d\n",
                        rs->me_addr,
                        rs->host_addr,
                        rs->status);

        /* if WD or iamthif client treat specially */

        if (is_treat_specially_client(&dev->wd_cl, rs)) {
                dev_dbg(&dev->pdev->dev, "successfully connected to WD client.\n");
                mei_watchdog_register(dev);

                return;
        }

        if (is_treat_specially_client(&dev->iamthif_cl, rs)) {
                dev->iamthif_state = MEI_IAMTHIF_IDLE;
                return;
        }
        list_for_each_entry_safe(pos, next, &dev->ctrl_rd_list.list, list) {

                cl = pos->cl;
                if (!cl) {
                        list_del(&pos->list);
                        return;
                }
                if (pos->fop_type == MEI_FOP_IOCTL) {
                        if (is_treat_specially_client(cl, rs)) {
                                list_del(&pos->list);
                                cl->status = 0;
                                cl->timer_count = 0;
                                break;
                        }
                }
        }
}


/**
 * mei_hbm_fw_disconnect_req - disconnect request initiated by me
 *  host sends disoconnect response
 *
 * @dev: the device structure.
 * @disconnect_req: disconnect request bus message from the me
 */
static void mei_hbm_fw_disconnect_req(struct mei_device *dev,
                struct hbm_client_connect_request *disconnect_req)
{
        struct mei_cl *cl, *next;
        const size_t len = sizeof(struct hbm_client_connect_response);

        list_for_each_entry_safe(cl, next, &dev->file_list, link) {
                if (mei_hbm_cl_addr_equal(cl, disconnect_req)) {
                        dev_dbg(&dev->pdev->dev, "disconnect request host client %d ME client %d.\n",
                                        disconnect_req->host_addr,
                                        disconnect_req->me_addr);
                        cl->state = MEI_FILE_DISCONNECTED;
                        cl->timer_count = 0;
                        if (cl == &dev->wd_cl)
                                dev->wd_pending = false;
                        else if (cl == &dev->iamthif_cl)
                                dev->iamthif_timer = 0;

                        /* prepare disconnect response */
                        mei_hbm_hdr(&dev->wr_ext_msg.hdr, len);
                        mei_hbm_cl_hdr(cl, CLIENT_DISCONNECT_RES_CMD,
                                         dev->wr_ext_msg.data, len);
                        break;
                }
        }
}


/**
 * mei_hbm_version_is_supported - checks whether the driver can
 *     support the hbm version of the device
 *
 * @dev: the device structure
 * returns true if driver can support hbm version of the device
 */
bool mei_hbm_version_is_supported(struct mei_device *dev)
{
        return  (dev->version.major_version < HBM_MAJOR_VERSION) ||
                (dev->version.major_version == HBM_MAJOR_VERSION &&
                 dev->version.minor_version <= HBM_MINOR_VERSION);
}

/**
 * mei_hbm_dispatch - bottom half read routine after ISR to
 * handle the read bus message cmd processing.
 *
 * @dev: the device structure
 * @mei_hdr: header of bus message
 */
void mei_hbm_dispatch(struct mei_device *dev, struct mei_msg_hdr *hdr)
{
        struct mei_bus_message *mei_msg;
        struct mei_me_client *me_client;
        struct hbm_host_version_response *version_res;
        struct hbm_client_connect_response *connect_res;
        struct hbm_client_connect_response *disconnect_res;
        struct hbm_client_connect_request *disconnect_req;
        struct hbm_flow_control *flow_control;
        struct hbm_props_response *props_res;
        struct hbm_host_enum_response *enum_res;

        /* read the message to our buffer */
        BUG_ON(hdr->length >= sizeof(dev->rd_msg_buf));
        mei_read_slots(dev, dev->rd_msg_buf, hdr->length);
        mei_msg = (struct mei_bus_message *)dev->rd_msg_buf;

        switch (mei_msg->hbm_cmd) {
        case HOST_START_RES_CMD:
                version_res = (struct hbm_host_version_response *)mei_msg;

                dev_dbg(&dev->pdev->dev, "HBM VERSION: DRIVER=%02d:%02d DEVICE=%02d:%02d\n",
                                HBM_MAJOR_VERSION, HBM_MINOR_VERSION,
                                version_res->me_max_version.major_version,
                                version_res->me_max_version.minor_version);

                if (version_res->host_version_supported) {
                        dev->version.major_version = HBM_MAJOR_VERSION;
                        dev->version.minor_version = HBM_MINOR_VERSION;
                } else {
                        dev->version.major_version =
                                version_res->me_max_version.major_version;
                        dev->version.minor_version =
                                version_res->me_max_version.minor_version;
                }

                if (!mei_hbm_version_is_supported(dev)) {
                        dev_warn(&dev->pdev->dev, "hbm version mismatch: stopping the driver.\n");

                        dev->hbm_state = MEI_HBM_STOP;
                        mei_hbm_stop_req_prepare(dev, &dev->wr_msg.hdr,
                                                dev->wr_msg.data);
                        mei_write_message(dev, &dev->wr_msg.hdr,
                                        dev->wr_msg.data);

                        return;
                }

                if (dev->dev_state == MEI_DEV_INIT_CLIENTS &&
                    dev->hbm_state == MEI_HBM_START) {
                        dev->init_clients_timer = 0;
                        mei_hbm_enum_clients_req(dev);
                } else {
                        dev_err(&dev->pdev->dev, "reset: wrong host start response\n");
                        mei_reset(dev, 1);
                        return;
                }

                wake_up_interruptible(&dev->wait_recvd_msg);
                dev_dbg(&dev->pdev->dev, "host start response message received.\n");
                break;

        case CLIENT_CONNECT_RES_CMD:
                connect_res = (struct hbm_client_connect_response *) mei_msg;
                mei_hbm_cl_connect_res(dev, connect_res);
                dev_dbg(&dev->pdev->dev, "client connect response message received.\n");
                wake_up(&dev->wait_recvd_msg);
                break;

        case CLIENT_DISCONNECT_RES_CMD:
                disconnect_res = (struct hbm_client_connect_response *) mei_msg;
                mei_hbm_cl_disconnect_res(dev, disconnect_res);
                dev_dbg(&dev->pdev->dev, "client disconnect response message received.\n");
                wake_up(&dev->wait_recvd_msg);
                break;

        case MEI_FLOW_CONTROL_CMD:
                flow_control = (struct hbm_flow_control *) mei_msg;
                mei_hbm_cl_flow_control_res(dev, flow_control);
                dev_dbg(&dev->pdev->dev, "client flow control response message received.\n");
                break;

        case HOST_CLIENT_PROPERTIES_RES_CMD:
                props_res = (struct hbm_props_response *)mei_msg;
                me_client = &dev->me_clients[dev->me_client_presentation_num];

                if (props_res->status || !dev->me_clients) {
                        dev_err(&dev->pdev->dev, "reset: properties response hbm wrong status.\n");
                        mei_reset(dev, 1);
                        return;
                }

                if (me_client->client_id != props_res->address) {
                        dev_err(&dev->pdev->dev, "reset: host properties response address mismatch\n");
                        mei_reset(dev, 1);
                        return;
                }

                if (dev->dev_state != MEI_DEV_INIT_CLIENTS ||
                    dev->hbm_state != MEI_HBM_CLIENT_PROPERTIES) {
                        dev_err(&dev->pdev->dev, "reset: unexpected properties response\n");
                        mei_reset(dev, 1);

                        return;
                }

                me_client->props = props_res->client_properties;
                dev->me_client_index++;
                dev->me_client_presentation_num++;

                /* request property for the next client */
                mei_hbm_prop_req(dev);

                break;

        case HOST_ENUM_RES_CMD:
                enum_res = (struct hbm_host_enum_response *) mei_msg;
                memcpy(dev->me_clients_map, enum_res->valid_addresses, 32);
                if (dev->dev_state == MEI_DEV_INIT_CLIENTS &&
                    dev->hbm_state == MEI_HBM_ENUM_CLIENTS) {
                                dev->init_clients_timer = 0;
                                dev->me_client_presentation_num = 0;
                                dev->me_client_index = 0;
                                mei_hbm_me_cl_allocate(dev);
                                dev->hbm_state = MEI_HBM_CLIENT_PROPERTIES;

                                /* first property reqeust */
                                mei_hbm_prop_req(dev);
                } else {
                        dev_err(&dev->pdev->dev, "reset: unexpected enumeration response hbm.\n");
                        mei_reset(dev, 1);
                        return;
                }
                break;

        case HOST_STOP_RES_CMD:

                if (dev->hbm_state != MEI_HBM_STOP)
                        dev_err(&dev->pdev->dev, "unexpected stop response hbm.\n");
                dev->dev_state = MEI_DEV_DISABLED;
                dev_info(&dev->pdev->dev, "reset: FW stop response.\n");
                mei_reset(dev, 1);
                break;

        case CLIENT_DISCONNECT_REQ_CMD:
                /* search for client */
                disconnect_req = (struct hbm_client_connect_request *)mei_msg;
                mei_hbm_fw_disconnect_req(dev, disconnect_req);
                break;

        case ME_STOP_REQ_CMD:

                dev->hbm_state = MEI_HBM_STOP;
                mei_hbm_stop_req_prepare(dev, &dev->wr_ext_msg.hdr,
                                        dev->wr_ext_msg.data);
                break;
        default:
                BUG();
                break;

        }
}