drivers/misc/ibmasm/r_heartbeat.c

   1
   2 /*
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  16  *
  17  * Copyright (C) IBM Corporation, 2004
  18  *
  19  * Author: Max Asböck <amax@us.ibm.com>
  20  *
  21  */
  22
  23 #include <linux/sched/signal.h>
  24 #include "ibmasm.h"
  25 #include "dot_command.h"
  26
  27 /*
  28  * Reverse Heartbeat, i.e. heartbeats sent from the driver to the
  29  * service processor.
  30  * These heartbeats are initiated by user level programs.
  31  */
  32
  33 /* the reverse heartbeat dot command */
  34 #pragma pack(1)
  35 static struct {
  36         struct dot_command_header       header;
  37         unsigned char                   command[3];
  38 } rhb_dot_cmd = {
  39         .header = {
  40                 .type =         sp_read,
  41                 .command_size = 3,
  42                 .data_size =    0,
  43                 .status =       0
  44         },
  45         .command = { 4, 3, 6 }
  46 };
  47 #pragma pack()
  48
  49 void ibmasm_init_reverse_heartbeat(struct service_processor *sp, struct reverse_heartbeat *rhb)
  50 {
  51         init_waitqueue_head(&rhb->wait);
  52         rhb->stopped = 0;
  53 }
  54
  55 /**
  56  * start_reverse_heartbeat
  57  * Loop forever, sending a reverse heartbeat dot command to the service
  58  * processor, then sleeping. The loop comes to an end if the service
  59  * processor fails to respond 3 times or we were interrupted.
  60  */
  61 int ibmasm_start_reverse_heartbeat(struct service_processor *sp, struct reverse_heartbeat *rhb)
  62 {
  63         struct command *cmd;
  64         int times_failed = 0;
  65         int result = 1;
  66
  67         cmd = ibmasm_new_command(sp, sizeof rhb_dot_cmd);
  68         if (!cmd)
  69                 return -ENOMEM;
  70
  71         while (times_failed < 3) {
  72                 memcpy(cmd->buffer, (void *)&rhb_dot_cmd, sizeof rhb_dot_cmd);
  73                 cmd->status = IBMASM_CMD_PENDING;
  74                 ibmasm_exec_command(sp, cmd);
  75                 ibmasm_wait_for_response(cmd, IBMASM_CMD_TIMEOUT_NORMAL);
  76
  77                 if (cmd->status != IBMASM_CMD_COMPLETE)
  78                         times_failed++;
  79
  80                 wait_event_interruptible_timeout(rhb->wait,
  81                         rhb->stopped,
  82                         REVERSE_HEARTBEAT_TIMEOUT * HZ);
  83
  84                 if (signal_pending(current) || rhb->stopped) {
  85                         result = -EINTR;
  86                         break;
  87                 }
  88         }
  89         command_put(cmd);
  90         rhb->stopped = 0;
  91
  92         return result;
  93 }
  94
  95 void ibmasm_stop_reverse_heartbeat(struct reverse_heartbeat *rhb)
  96 {
  97         rhb->stopped = 1;
  98         wake_up_interruptible(&rhb->wait);
  99 }