1// SPDX-License-Identifier: GPL-2.0-or-later
2
3/*
4 *
5 * Copyright (C) IBM Corporation, 2004
6 *
7 * Author: Max Asb��ck <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, 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