acpi_pad: build only on X86
[linux-2.6/linux-acpi-2.6.git] / drivers / misc / ibmasm / heartbeat.c
blob1bc4306572a477aa6d440187c5bb7db4a23e7a26
2 /*
3 * IBM ASM Service Processor Device Driver
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 * Copyright (C) IBM Corporation, 2004
21 * Author: Max Asböck <amax@us.ibm.com>
25 #include <linux/notifier.h>
26 #include "ibmasm.h"
27 #include "dot_command.h"
28 #include "lowlevel.h"
30 static int suspend_heartbeats = 0;
33 * Once the driver indicates to the service processor that it is running
34 * - see send_os_state() - the service processor sends periodic heartbeats
35 * to the driver. The driver must respond to the heartbeats or else the OS
36 * will be rebooted.
37 * In the case of a panic the interrupt handler continues to work and thus
38 * continues to respond to heartbeats, making the service processor believe
39 * the OS is still running and thus preventing a reboot.
40 * To prevent this from happening a callback is added the panic_notifier_list.
41 * Before responding to a heartbeat the driver checks if a panic has happened,
42 * if yes it suspends heartbeat, causing the service processor to reboot as
43 * expected.
45 static int panic_happened(struct notifier_block *n, unsigned long val, void *v)
47 suspend_heartbeats = 1;
48 return 0;
51 static struct notifier_block panic_notifier = { panic_happened, NULL, 1 };
53 void ibmasm_register_panic_notifier(void)
55 atomic_notifier_chain_register(&panic_notifier_list, &panic_notifier);
58 void ibmasm_unregister_panic_notifier(void)
60 atomic_notifier_chain_unregister(&panic_notifier_list,
61 &panic_notifier);
65 int ibmasm_heartbeat_init(struct service_processor *sp)
67 sp->heartbeat = ibmasm_new_command(sp, HEARTBEAT_BUFFER_SIZE);
68 if (sp->heartbeat == NULL)
69 return -ENOMEM;
71 return 0;
74 void ibmasm_heartbeat_exit(struct service_processor *sp)
76 char tsbuf[32];
78 dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
79 ibmasm_wait_for_response(sp->heartbeat, IBMASM_CMD_TIMEOUT_NORMAL);
80 dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
81 suspend_heartbeats = 1;
82 command_put(sp->heartbeat);
85 void ibmasm_receive_heartbeat(struct service_processor *sp, void *message, size_t size)
87 struct command *cmd = sp->heartbeat;
88 struct dot_command_header *header = (struct dot_command_header *)cmd->buffer;
89 char tsbuf[32];
91 dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
92 if (suspend_heartbeats)
93 return;
95 /* return the received dot command to sender */
96 cmd->status = IBMASM_CMD_PENDING;
97 size = min(size, cmd->buffer_size);
98 memcpy_fromio(cmd->buffer, message, size);
99 header->type = sp_write;
100 ibmasm_exec_command(sp, cmd);