11a59d1b8SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later 21da177e4SLinus Torvalds 31da177e4SLinus Torvalds /* 41da177e4SLinus Torvalds * IBM ASM Service Processor Device Driver 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * Copyright (C) IBM Corporation, 2004 71da177e4SLinus Torvalds * 8d36b6910SAl Viro * Author: Max Asböck <amax@us.ibm.com> 91da177e4SLinus Torvalds */ 101da177e4SLinus Torvalds 111da177e4SLinus Torvalds #include <linux/notifier.h> 12*f39650deSAndy Shevchenko #include <linux/panic_notifier.h> 131da177e4SLinus Torvalds #include "ibmasm.h" 141da177e4SLinus Torvalds #include "dot_command.h" 1588187605SMax Asbock #include "lowlevel.h" 161da177e4SLinus Torvalds 171da177e4SLinus Torvalds static int suspend_heartbeats = 0; 181da177e4SLinus Torvalds 191da177e4SLinus Torvalds /* 201da177e4SLinus Torvalds * Once the driver indicates to the service processor that it is running 211da177e4SLinus Torvalds * - see send_os_state() - the service processor sends periodic heartbeats 221da177e4SLinus Torvalds * to the driver. The driver must respond to the heartbeats or else the OS 231da177e4SLinus Torvalds * will be rebooted. 241da177e4SLinus Torvalds * In the case of a panic the interrupt handler continues to work and thus 251da177e4SLinus Torvalds * continues to respond to heartbeats, making the service processor believe 261da177e4SLinus Torvalds * the OS is still running and thus preventing a reboot. 271da177e4SLinus Torvalds * To prevent this from happening a callback is added the panic_notifier_list. 281da177e4SLinus Torvalds * Before responding to a heartbeat the driver checks if a panic has happened, 291da177e4SLinus Torvalds * if yes it suspends heartbeat, causing the service processor to reboot as 301da177e4SLinus Torvalds * expected. 311da177e4SLinus Torvalds */ 321da177e4SLinus Torvalds static int panic_happened(struct notifier_block *n, unsigned long val, void *v) 331da177e4SLinus Torvalds { 341da177e4SLinus Torvalds suspend_heartbeats = 1; 351da177e4SLinus Torvalds return 0; 361da177e4SLinus Torvalds } 371da177e4SLinus Torvalds 381da177e4SLinus Torvalds static struct notifier_block panic_notifier = { panic_happened, NULL, 1 }; 391da177e4SLinus Torvalds 401da177e4SLinus Torvalds void ibmasm_register_panic_notifier(void) 411da177e4SLinus Torvalds { 42e041c683SAlan Stern atomic_notifier_chain_register(&panic_notifier_list, &panic_notifier); 431da177e4SLinus Torvalds } 441da177e4SLinus Torvalds 451da177e4SLinus Torvalds void ibmasm_unregister_panic_notifier(void) 461da177e4SLinus Torvalds { 47e041c683SAlan Stern atomic_notifier_chain_unregister(&panic_notifier_list, 48e041c683SAlan Stern &panic_notifier); 491da177e4SLinus Torvalds } 501da177e4SLinus Torvalds 511da177e4SLinus Torvalds 521da177e4SLinus Torvalds int ibmasm_heartbeat_init(struct service_processor *sp) 531da177e4SLinus Torvalds { 5488187605SMax Asbock sp->heartbeat = ibmasm_new_command(sp, HEARTBEAT_BUFFER_SIZE); 551da177e4SLinus Torvalds if (sp->heartbeat == NULL) 561da177e4SLinus Torvalds return -ENOMEM; 571da177e4SLinus Torvalds 581da177e4SLinus Torvalds return 0; 591da177e4SLinus Torvalds } 601da177e4SLinus Torvalds 611da177e4SLinus Torvalds void ibmasm_heartbeat_exit(struct service_processor *sp) 621da177e4SLinus Torvalds { 6388187605SMax Asbock char tsbuf[32]; 6488187605SMax Asbock 656e574195SHarvey Harrison dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf)); 6688187605SMax Asbock ibmasm_wait_for_response(sp->heartbeat, IBMASM_CMD_TIMEOUT_NORMAL); 676e574195SHarvey Harrison dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf)); 6888187605SMax Asbock suspend_heartbeats = 1; 691da177e4SLinus Torvalds command_put(sp->heartbeat); 701da177e4SLinus Torvalds } 711da177e4SLinus Torvalds 721da177e4SLinus Torvalds void ibmasm_receive_heartbeat(struct service_processor *sp, void *message, size_t size) 731da177e4SLinus Torvalds { 741da177e4SLinus Torvalds struct command *cmd = sp->heartbeat; 751da177e4SLinus Torvalds struct dot_command_header *header = (struct dot_command_header *)cmd->buffer; 7688187605SMax Asbock char tsbuf[32]; 771da177e4SLinus Torvalds 786e574195SHarvey Harrison dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf)); 791da177e4SLinus Torvalds if (suspend_heartbeats) 801da177e4SLinus Torvalds return; 811da177e4SLinus Torvalds 821da177e4SLinus Torvalds /* return the received dot command to sender */ 831da177e4SLinus Torvalds cmd->status = IBMASM_CMD_PENDING; 841da177e4SLinus Torvalds size = min(size, cmd->buffer_size); 8588187605SMax Asbock memcpy_fromio(cmd->buffer, message, size); 861da177e4SLinus Torvalds header->type = sp_write; 871da177e4SLinus Torvalds ibmasm_exec_command(sp, cmd); 881da177e4SLinus Torvalds } 89