1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | |
3 | /* |
4 | * IBM ASM Service Processor Device Driver |
5 | * |
6 | * Copyright (C) IBM Corporation, 2004 |
7 | * |
8 | * Author: Max Asböck <amax@us.ibm.com> |
9 | */ |
10 | |
11 | #include <linux/notifier.h> |
12 | #include <linux/panic_notifier.h> |
13 | #include "ibmasm.h" |
14 | #include "dot_command.h" |
15 | #include "lowlevel.h" |
16 | |
17 | static int suspend_heartbeats = 0; |
18 | |
19 | /* |
20 | * Once the driver indicates to the service processor that it is running |
21 | * - see send_os_state() - the service processor sends periodic heartbeats |
22 | * to the driver. The driver must respond to the heartbeats or else the OS |
23 | * will be rebooted. |
24 | * In the case of a panic the interrupt handler continues to work and thus |
25 | * continues to respond to heartbeats, making the service processor believe |
26 | * the OS is still running and thus preventing a reboot. |
27 | * To prevent this from happening a callback is added the panic_notifier_list. |
28 | * Before responding to a heartbeat the driver checks if a panic has happened, |
29 | * if yes it suspends heartbeat, causing the service processor to reboot as |
30 | * expected. |
31 | */ |
32 | static int panic_happened(struct notifier_block *n, unsigned long val, void *v) |
33 | { |
34 | suspend_heartbeats = 1; |
35 | return 0; |
36 | } |
37 | |
38 | static struct notifier_block panic_notifier = { panic_happened, NULL, 1 }; |
39 | |
40 | void ibmasm_register_panic_notifier(void) |
41 | { |
42 | atomic_notifier_chain_register(nh: &panic_notifier_list, nb: &panic_notifier); |
43 | } |
44 | |
45 | void ibmasm_unregister_panic_notifier(void) |
46 | { |
47 | atomic_notifier_chain_unregister(nh: &panic_notifier_list, |
48 | nb: &panic_notifier); |
49 | } |
50 | |
51 | |
52 | int ibmasm_heartbeat_init(struct service_processor *sp) |
53 | { |
54 | sp->heartbeat = ibmasm_new_command(sp, HEARTBEAT_BUFFER_SIZE); |
55 | if (sp->heartbeat == NULL) |
56 | return -ENOMEM; |
57 | |
58 | return 0; |
59 | } |
60 | |
61 | void ibmasm_heartbeat_exit(struct service_processor *sp) |
62 | { |
63 | char tsbuf[32]; |
64 | |
65 | dbg("%s:%d at %s\n" , __func__, __LINE__, get_timestamp(tsbuf)); |
66 | ibmasm_wait_for_response(cmd: sp->heartbeat, IBMASM_CMD_TIMEOUT_NORMAL); |
67 | dbg("%s:%d at %s\n" , __func__, __LINE__, get_timestamp(tsbuf)); |
68 | suspend_heartbeats = 1; |
69 | command_put(cmd: sp->heartbeat); |
70 | } |
71 | |
72 | void ibmasm_receive_heartbeat(struct service_processor *sp, void *message, size_t size) |
73 | { |
74 | struct command *cmd = sp->heartbeat; |
75 | struct dot_command_header * = (struct dot_command_header *)cmd->buffer; |
76 | char tsbuf[32]; |
77 | |
78 | dbg("%s:%d at %s\n" , __func__, __LINE__, get_timestamp(tsbuf)); |
79 | if (suspend_heartbeats) |
80 | return; |
81 | |
82 | /* return the received dot command to sender */ |
83 | cmd->status = IBMASM_CMD_PENDING; |
84 | size = min(size, cmd->buffer_size); |
85 | memcpy_fromio(cmd->buffer, message, size); |
86 | header->type = sp_write; |
87 | ibmasm_exec_command(sp, cmd); |
88 | } |
89 | |