// SPDX-License-Identifier: GPL-2.0-or-later

/*
 *
 * Copyright (C) IBM Corporation, 2004
 *
 * Author: Max Asböck <amax@us.ibm.com>
 */

#include <linux/sched/signal.h>
#include "ibmasm.h"
#include "dot_command.h"

/*
 * Reverse Heartbeat, i.e. heartbeats sent from the driver to the
 * service processor.
 * These heartbeats are initiated by user level programs.
 */

/* the reverse heartbeat dot command */
#pragma pack(1)
static struct {
        struct dot_command_header       header;
        unsigned char                   command[3];
} rhb_dot_cmd = {
        .header = {
                .type =         sp_read,
                .command_size = 3,
                .data_size =    0,
                .status =       0
        },
        .command = { 4, 3, 6 }
};
#pragma pack()

void ibmasm_init_reverse_heartbeat(struct service_processor *sp, struct reverse_heartbeat *rhb)
{
        init_waitqueue_head(&rhb->wait);
        rhb->stopped = 0;
}

/*
 * start_reverse_heartbeat
 * Loop forever, sending a reverse heartbeat dot command to the service
 * processor, then sleeping. The loop comes to an end if the service
 * processor fails to respond 3 times or we were interrupted.
 */
int ibmasm_start_reverse_heartbeat(struct service_processor *sp, struct reverse_heartbeat *rhb)
{
        struct command *cmd;
        int times_failed = 0;
        int result = 1;

        cmd = ibmasm_new_command(sp, sizeof rhb_dot_cmd);
        if (!cmd)
                return -ENOMEM;

        while (times_failed < 3) {
                memcpy(cmd->buffer, (void *)&rhb_dot_cmd, sizeof rhb_dot_cmd);
                cmd->status = IBMASM_CMD_PENDING;
                ibmasm_exec_command(sp, cmd);
                ibmasm_wait_for_response(cmd, IBMASM_CMD_TIMEOUT_NORMAL);

                if (cmd->status != IBMASM_CMD_COMPLETE)
                        times_failed++;

                wait_event_interruptible_timeout(rhb->wait,
                        rhb->stopped,
                        REVERSE_HEARTBEAT_TIMEOUT * HZ);

                if (signal_pending(current) || rhb->stopped) {
                        result = -EINTR;
                        break;
                }
        }
        command_put(cmd);
        rhb->stopped = 0;

        return result;
}

void ibmasm_stop_reverse_heartbeat(struct reverse_heartbeat *rhb)
{
        rhb->stopped = 1;
        wake_up_interruptible(&rhb->wait);
}