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kernel/linux-rt-4.4.41/drivers/misc/ibmasm/r_heartbeat.c 2.55 KB
5113f6f70   김현기   kernel add
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  /*
   * 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/sched.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);
  }