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)
22static 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
36void 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 */
48int 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, buffer_size: 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
82void ibmasm_stop_reverse_heartbeat(struct reverse_heartbeat *rhb)
83{
84 rhb->stopped = 1;
85 wake_up_interruptible(&rhb->wait);
86}
87

source code of linux/drivers/misc/ibmasm/r_heartbeat.c