heartbeat.c

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/*
 * IBM ASM Service Processor Device Driver
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Copyright (C) IBM Corporation, 2004
 *
 * Author: Max Asböck <[email protected]>
 *
 */

#include <linux/notifier.h>
#include "ibmasm.h"
#include "dot_command.h"
#include "lowlevel.h"

static int suspend_heartbeats = 0;

/*
 * Once the driver indicates to the service processor that it is running
 * - see send_os_state() - the service processor sends periodic heartbeats
 * to the driver. The driver must respond to the heartbeats or else the OS
 * will be rebooted.
 * In the case of a panic the interrupt handler continues to work and thus
 * continues to respond to heartbeats, making the service processor believe
 * the OS is still running and thus preventing a reboot.
 * To prevent this from happening a callback is added the panic_notifier_list.
 * Before responding to a heartbeat the driver checks if a panic has happened,
 * if yes it suspends heartbeat, causing the service processor to reboot as
 * expected.
 */
static int panic_happened(struct notifier_block *n, unsigned long val, void *v)
{
    suspend_heartbeats = 1;
    return 0;
}

static struct notifier_block panic_notifier = { panic_happened, NULL, 1 };

void ibmasm_register_panic_notifier(void)
{
    atomic_notifier_chain_register(&panic_notifier_list, &panic_notifier);
}

void ibmasm_unregister_panic_notifier(void)
{
    atomic_notifier_chain_unregister(&panic_notifier_list,
            &panic_notifier);
}


int ibmasm_heartbeat_init(struct service_processor *sp)
{
    sp->heartbeat = ibmasm_new_command(sp, HEARTBEAT_BUFFER_SIZE);
    if (sp->heartbeat == NULL)
        return -ENOMEM;

    return 0;
}

void ibmasm_heartbeat_exit(struct service_processor *sp)
{
    char tsbuf[32];

    dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
    ibmasm_wait_for_response(sp->heartbeat, IBMASM_CMD_TIMEOUT_NORMAL);
    dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
    suspend_heartbeats = 1;
    command_put(sp->heartbeat);
}

void ibmasm_receive_heartbeat(struct service_processor *sp,  void *message, size_t size)
{
    struct command *cmd = sp->heartbeat;
    struct dot_command_header *header = (struct dot_command_header *)cmd->buffer;
    char tsbuf[32];

    dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
    if (suspend_heartbeats)
        return;

    /* return the received dot command to sender */
    cmd->status = IBMASM_CMD_PENDING;
    size = min(size, cmd->buffer_size);
    memcpy_fromio(cmd->buffer, message, size);
    header->type = sp_write;
    ibmasm_exec_command(sp, cmd);
}