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
pvpanic_send_event(unsigned int event)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
pvpanic_panic_notify(struct notifier_block * nb,unsigned long code,void * unused)46 pvpanic_panic_notify(struct notifier_block *nb, unsigned long code, 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
pvpanic_remove(void * param)63 static void pvpanic_remove(void *param)
64 {
65 struct pvpanic_instance *pi_cur, *pi_next;
66 struct pvpanic_instance *pi = param;
67
68 spin_lock(&pvpanic_lock);
69 list_for_each_entry_safe(pi_cur, pi_next, &pvpanic_list, list) {
70 if (pi_cur == pi) {
71 list_del(&pi_cur->list);
72 break;
73 }
74 }
75 spin_unlock(&pvpanic_lock);
76 }
77
devm_pvpanic_probe(struct device * dev,struct pvpanic_instance * pi)78 int devm_pvpanic_probe(struct device *dev, struct pvpanic_instance *pi)
79 {
80 if (!pi || !pi->base)
81 return -EINVAL;
82
83 spin_lock(&pvpanic_lock);
84 list_add(&pi->list, &pvpanic_list);
85 spin_unlock(&pvpanic_lock);
86
87 dev_set_drvdata(dev, pi);
88
89 return devm_add_action_or_reset(dev, pvpanic_remove, pi);
90 }
91 EXPORT_SYMBOL_GPL(devm_pvpanic_probe);
92
pvpanic_init(void)93 static int pvpanic_init(void)
94 {
95 INIT_LIST_HEAD(&pvpanic_list);
96 spin_lock_init(&pvpanic_lock);
97
98 atomic_notifier_chain_register(&panic_notifier_list, &pvpanic_panic_nb);
99
100 return 0;
101 }
102 module_init(pvpanic_init);
103
pvpanic_exit(void)104 static void pvpanic_exit(void)
105 {
106 atomic_notifier_chain_unregister(&panic_notifier_list, &pvpanic_panic_nb);
107
108 }
109 module_exit(pvpanic_exit);
110