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
ibmasm_init_reverse_heartbeat(struct service_processor * sp,struct reverse_heartbeat * rhb)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 */
ibmasm_start_reverse_heartbeat(struct service_processor * sp,struct reverse_heartbeat * rhb)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
ibmasm_stop_reverse_heartbeat(struct reverse_heartbeat * rhb)82 void ibmasm_stop_reverse_heartbeat(struct reverse_heartbeat *rhb)
83 {
84 rhb->stopped = 1;
85 wake_up_interruptible(&rhb->wait);
86 }
87
