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 <linux/panic_notifier.h> 13 #include "ibmasm.h" 14 #include "dot_command.h" 15 #include "lowlevel.h" 16 17 static int suspend_heartbeats = 0; 18 19 /* 20 * Once the driver indicates to the service processor that it is running 21 * - see send_os_state() - the service processor sends periodic heartbeats 22 * to the driver. The driver must respond to the heartbeats or else the OS 23 * will be rebooted. 24 * In the case of a panic the interrupt handler continues to work and thus 25 * continues to respond to heartbeats, making the service processor believe 26 * 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 as 30 * expected. 31 */ 32 static int panic_happened(struct notifier_block *n, unsigned long val, void *v) 33 { 34 suspend_heartbeats = 1; 35 return 0; 36 } 37 38 static struct notifier_block panic_notifier = { panic_happened, NULL, 1 }; 39 40 void ibmasm_register_panic_notifier(void) 41 { 42 atomic_notifier_chain_register(&panic_notifier_list, &panic_notifier); 43 } 44 45 void ibmasm_unregister_panic_notifier(void) 46 { 47 atomic_notifier_chain_unregister(&panic_notifier_list, 48 &panic_notifier); 49 } 50 51 52 int 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 61 void 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 72 void 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