1 // SPDX-License-Identifier: GPL-2.0-or-later
2 
3 /*
4  *
5  * Copyright (C) IBM Corporation, 2004
6  *
7  * Author: Max Asböck <amax@us.ibm.com>
8  */
9 
10 #include <linux/sched/signal.h>
11 #include "ibmasm.h"
12 #include "dot_command.h"
13 
14 /*
15  * Reverse Heartbeat, i.e. heartbeats sent from the driver to the
16  * service processor.
17  * These heartbeats are initiated by user level programs.
18  */
19 
20 /* the reverse heartbeat dot command */
21 #pragma pack(1)
22 static struct {
23 	struct dot_command_header	header;
24 	unsigned char			command[3];
25 } rhb_dot_cmd = {
26 	.header = {
27 		.type =		sp_read,
28 		.command_size = 3,
29 		.data_size =	0,
30 		.status =	0
31 	},
32 	.command = { 4, 3, 6 }
33 };
34 #pragma pack()
35 
36 void ibmasm_init_reverse_heartbeat(struct service_processor *sp, struct reverse_heartbeat *rhb)
37 {
38 	init_waitqueue_head(&rhb->wait);
39 	rhb->stopped = 0;
40 }
41 
42 /*
43  * start_reverse_heartbeat
44  * Loop forever, sending a reverse heartbeat dot command to the service
45  * processor, then sleeping. The loop comes to an end if the service
46  * processor fails to respond 3 times or we were interrupted.
47  */
48 int ibmasm_start_reverse_heartbeat(struct service_processor *sp, struct reverse_heartbeat *rhb)
49 {
50 	struct command *cmd;
51 	int times_failed = 0;
52 	int result = 1;
53 
54 	cmd = ibmasm_new_command(sp, sizeof rhb_dot_cmd);
55 	if (!cmd)
56 		return -ENOMEM;
57 
58 	while (times_failed < 3) {
59 		memcpy(cmd->buffer, (void *)&rhb_dot_cmd, sizeof rhb_dot_cmd);
60 		cmd->status = IBMASM_CMD_PENDING;
61 		ibmasm_exec_command(sp, cmd);
62 		ibmasm_wait_for_response(cmd, IBMASM_CMD_TIMEOUT_NORMAL);
63 
64 		if (cmd->status != IBMASM_CMD_COMPLETE)
65 			times_failed++;
66 
67 		wait_event_interruptible_timeout(rhb->wait,
68 			rhb->stopped,
69 			REVERSE_HEARTBEAT_TIMEOUT * HZ);
70 
71 		if (signal_pending(current) || rhb->stopped) {
72 			result = -EINTR;
73 			break;
74 		}
75 	}
76 	command_put(cmd);
77 	rhb->stopped = 0;
78 
79 	return result;
80 }
81 
82 void ibmasm_stop_reverse_heartbeat(struct reverse_heartbeat *rhb)
83 {
84 	rhb->stopped = 1;
85 	wake_up_interruptible(&rhb->wait);
86 }
87