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