1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Pvpanic Device Support 4 * 5 * Copyright (C) 2013 Fujitsu. 6 * Copyright (C) 2018 ZTE. 7 * Copyright (C) 2021 Oracle. 8 */ 9 10 #include <linux/io.h> 11 #include <linux/kernel.h> 12 #include <linux/kexec.h> 13 #include <linux/mod_devicetable.h> 14 #include <linux/module.h> 15 #include <linux/platform_device.h> 16 #include <linux/panic_notifier.h> 17 #include <linux/types.h> 18 #include <linux/cdev.h> 19 #include <linux/list.h> 20 21 #include <uapi/misc/pvpanic.h> 22 23 #include "pvpanic.h" 24 25 MODULE_AUTHOR("Mihai Carabas <mihai.carabas@oracle.com>"); 26 MODULE_DESCRIPTION("pvpanic device driver "); 27 MODULE_LICENSE("GPL"); 28 29 static struct list_head pvpanic_list; 30 static spinlock_t pvpanic_lock; 31 32 static void 33 pvpanic_send_event(unsigned int event) 34 { 35 struct pvpanic_instance *pi_cur; 36 37 spin_lock(&pvpanic_lock); 38 list_for_each_entry(pi_cur, &pvpanic_list, list) { 39 if (event & pi_cur->capability & pi_cur->events) 40 iowrite8(event, pi_cur->base); 41 } 42 spin_unlock(&pvpanic_lock); 43 } 44 45 static int 46 pvpanic_panic_notify(struct notifier_block *nb, unsigned long code, 47 void *unused) 48 { 49 unsigned int event = PVPANIC_PANICKED; 50 51 if (kexec_crash_loaded()) 52 event = PVPANIC_CRASH_LOADED; 53 54 pvpanic_send_event(event); 55 56 return NOTIFY_DONE; 57 } 58 59 static struct notifier_block pvpanic_panic_nb = { 60 .notifier_call = pvpanic_panic_notify, 61 .priority = 1, /* let this called before broken drm_fb_helper */ 62 }; 63 64 int pvpanic_probe(struct pvpanic_instance *pi) 65 { 66 if (!pi || !pi->base) 67 return -EINVAL; 68 69 spin_lock(&pvpanic_lock); 70 list_add(&pi->list, &pvpanic_list); 71 spin_unlock(&pvpanic_lock); 72 73 return 0; 74 } 75 EXPORT_SYMBOL_GPL(pvpanic_probe); 76 77 void pvpanic_remove(struct pvpanic_instance *pi) 78 { 79 struct pvpanic_instance *pi_cur, *pi_next; 80 81 if (!pi) 82 return; 83 84 spin_lock(&pvpanic_lock); 85 list_for_each_entry_safe(pi_cur, pi_next, &pvpanic_list, list) { 86 if (pi_cur == pi) { 87 list_del(&pi_cur->list); 88 break; 89 } 90 } 91 spin_unlock(&pvpanic_lock); 92 } 93 EXPORT_SYMBOL_GPL(pvpanic_remove); 94 95 static int pvpanic_init(void) 96 { 97 INIT_LIST_HEAD(&pvpanic_list); 98 spin_lock_init(&pvpanic_lock); 99 100 atomic_notifier_chain_register(&panic_notifier_list, 101 &pvpanic_panic_nb); 102 103 return 0; 104 } 105 106 static void pvpanic_exit(void) 107 { 108 atomic_notifier_chain_unregister(&panic_notifier_list, 109 &pvpanic_panic_nb); 110 111 } 112 113 module_init(pvpanic_init); 114 module_exit(pvpanic_exit); 115