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1// SPDX-License-Identifier: GPL-2.0-or-later2 3/*4 * IBM ASM Service Processor Device Driver5 *6 * Copyright (C) IBM Corporation, 20047 *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 17static int suspend_heartbeats = 0;18 19/*20 * Once the driver indicates to the service processor that it is running21 * - see send_os_state() - the service processor sends periodic heartbeats22 * to the driver. The driver must respond to the heartbeats or else the OS23 * will be rebooted.24 * In the case of a panic the interrupt handler continues to work and thus25 * continues to respond to heartbeats, making the service processor believe26 * 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 as30 * expected.31 */32static int panic_happened(struct notifier_block *n, unsigned long val, void *v)33{34 suspend_heartbeats = 1;35 return 0;36}37 38static struct notifier_block panic_notifier = { panic_happened, NULL, 1 };39 40void ibmasm_register_panic_notifier(void)41{42 atomic_notifier_chain_register(&panic_notifier_list, &panic_notifier);43}44 45void ibmasm_unregister_panic_notifier(void)46{47 atomic_notifier_chain_unregister(&panic_notifier_list,48 &panic_notifier);49}50 51 52int 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 61void 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(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(sp->heartbeat);70}71 72void ibmasm_receive_heartbeat(struct service_processor *sp, void *message, size_t size)73{74 struct command *cmd = sp->heartbeat;75 struct dot_command_header *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