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