/*
   * 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 <amax@us.ibm.com>
   *
   */
  
  #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
  ", __func__, __LINE__, get_timestamp(tsbuf));
  	ibmasm_wait_for_response(sp->heartbeat, IBMASM_CMD_TIMEOUT_NORMAL);
  	dbg("%s:%d at %s
  ", __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
  ", __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);
  }