[deliverable/linux.git] / drivers / misc / ibmasm / heartbeat.c


/*
 * IBM ASM Service Processor Device Driver
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Copyright (C) IBM Corporation, 2004
 *
 * Author: Max Asböck <amax@us.ibm.com>
 *
 */

#include <linux/notifier.h>
#include "ibmasm.h"
#include "dot_command.h"
#include "lowlevel.h"

static int suspend_heartbeats = 0;

/*
 * Once the driver indicates to the service processor that it is running
 * - see send_os_state() - the service processor sends periodic heartbeats
 * to the driver. The driver must respond to the heartbeats or else the OS
 * will be rebooted.
 * In the case of a panic the interrupt handler continues to work and thus
 * continues to respond to heartbeats, making the service processor believe
 * the OS is still running and thus preventing a reboot.
 * To prevent this from happening a callback is added the panic_notifier_list.
 * Before responding to a heartbeat the driver checks if a panic has happened,
 * if yes it suspends heartbeat, causing the service processor to reboot as
 * expected.
 */
static int panic_happened(struct notifier_block *n, unsigned long val, void *v)
{
	suspend_heartbeats = 1;
	return 0;
}

static struct notifier_block panic_notifier = { panic_happened, NULL, 1 };

void ibmasm_register_panic_notifier(void)
{
	atomic_notifier_chain_register(&panic_notifier_list, &panic_notifier);
}

void ibmasm_unregister_panic_notifier(void)
{
	atomic_notifier_chain_unregister(&panic_notifier_list,
			&panic_notifier);
}


int ibmasm_heartbeat_init(struct service_processor *sp)
{
	sp->heartbeat = ibmasm_new_command(sp, HEARTBEAT_BUFFER_SIZE);
	if (sp->heartbeat == NULL)
		return -ENOMEM;

	return 0;
}

void ibmasm_heartbeat_exit(struct service_processor *sp)
{
	char tsbuf[32];

	dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
	ibmasm_wait_for_response(sp->heartbeat, IBMASM_CMD_TIMEOUT_NORMAL);
	dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
	suspend_heartbeats = 1;
	command_put(sp->heartbeat);
}

void ibmasm_receive_heartbeat(struct service_processor *sp,  void *message, size_t size)
{
	struct command *cmd = sp->heartbeat;
	struct dot_command_header *header = (struct dot_command_header *)cmd->buffer;
	char tsbuf[32];

	dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
	if (suspend_heartbeats)
		return;

	/* return the received dot command to sender */
	cmd->status = IBMASM_CMD_PENDING;
	size = min(size, cmd->buffer_size);
	memcpy_fromio(cmd->buffer, message, size);
	header->type = sp_write;
	ibmasm_exec_command(sp, cmd);
}
Commit	Line	Data
1da177e4 LT	1
	2	/*
	3	* IBM ASM Service Processor Device Driver
	4	*
	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.
	9	*
	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.
	14	*
	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.
	18	*
	19	* Copyright (C) IBM Corporation, 2004
	20	*
d36b6910	21	* Author: Max Asböck <amax@us.ibm.com>
1da177e4 LT	22	*
	23	*/
	24
	25	#include <linux/notifier.h>
	26	#include "ibmasm.h"
	27	#include "dot_command.h"
88187605	28	#include "lowlevel.h"
1da177e4 LT	29
	30	static int suspend_heartbeats = 0;
	31
	32	/*
	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.
	44	*/
	45	static int panic_happened(struct notifier_block n, unsigned long val, void v)
	46	{
	47	suspend_heartbeats = 1;
	48	return 0;
	49	}
	50
	51	static struct notifier_block panic_notifier = { panic_happened, NULL, 1 };
	52
	53	void ibmasm_register_panic_notifier(void)
	54	{
e041c683	55	atomic_notifier_chain_register(&panic_notifier_list, &panic_notifier);
1da177e4 LT	56	}
	57
	58	void ibmasm_unregister_panic_notifier(void)
	59	{
e041c683 AS	60	atomic_notifier_chain_unregister(&panic_notifier_list,
e041c683 AS	61	&panic_notifier);
1da177e4 LT	62	}
	63
	64
	65	int ibmasm_heartbeat_init(struct service_processor *sp)
	66	{
88187605	67	sp->heartbeat = ibmasm_new_command(sp, HEARTBEAT_BUFFER_SIZE);
1da177e4 LT	68	if (sp->heartbeat == NULL)
	69	return -ENOMEM;
	70
	71	return 0;
	72	}
	73
	74	void ibmasm_heartbeat_exit(struct service_processor *sp)
	75	{
88187605 MA	76	char tsbuf[32];
88187605 MA	77
6e574195	78	dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
88187605	79	ibmasm_wait_for_response(sp->heartbeat, IBMASM_CMD_TIMEOUT_NORMAL);
6e574195	80	dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
88187605	81	suspend_heartbeats = 1;
1da177e4 LT	82	command_put(sp->heartbeat);
	83	}
	84
	85	void ibmasm_receive_heartbeat(struct service_processor sp, void message, size_t size)
	86	{
	87	struct command *cmd = sp->heartbeat;
	88	struct dot_command_header header = (struct dot_command_header )cmd->buffer;
88187605	89	char tsbuf[32];
1da177e4	90
6e574195	91	dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
1da177e4 LT	92	if (suspend_heartbeats)
	93	return;
	94
	95	/* return the received dot command to sender */
	96	cmd->status = IBMASM_CMD_PENDING;
	97	size = min(size, cmd->buffer_size);
88187605	98	memcpy_fromio(cmd->buffer, message, size);
1da177e4 LT	99	header->type = sp_write;
	100	ibmasm_exec_command(sp, cmd);
	101	}