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 }
100