1 /*
2 * pvpanic.c - pvpanic Device Support
3 *
4 * Copyright (C) 2013 Fujitsu.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/init.h>
26 #include <linux/types.h>
27 #include <linux/acpi.h>
28
29 MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>");
30 MODULE_DESCRIPTION("pvpanic device driver");
31 MODULE_LICENSE("GPL");
32
33 static int pvpanic_add(struct acpi_device *device);
34 static int pvpanic_remove(struct acpi_device *device);
35
36 static const struct acpi_device_id pvpanic_device_ids[] = {
37 { "QEMU0001", 0 },
38 { "", 0 },
39 };
40 MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
41
42 #define PVPANIC_PANICKED (1 << 0)
43
44 static u16 port;
45
46 static struct acpi_driver pvpanic_driver = {
47 .name = "pvpanic",
48 .class = "QEMU",
49 .ids = pvpanic_device_ids,
50 .ops = {
51 .add = pvpanic_add,
52 .remove = pvpanic_remove,
53 },
54 .owner = THIS_MODULE,
55 };
56
57 static void
pvpanic_send_event(unsigned int event)58 pvpanic_send_event(unsigned int event)
59 {
60 outb(event, port);
61 }
62
63 static int
pvpanic_panic_notify(struct notifier_block * nb,unsigned long code,void * unused)64 pvpanic_panic_notify(struct notifier_block *nb, unsigned long code,
65 void *unused)
66 {
67 pvpanic_send_event(PVPANIC_PANICKED);
68 return NOTIFY_DONE;
69 }
70
71 static struct notifier_block pvpanic_panic_nb = {
72 .notifier_call = pvpanic_panic_notify,
73 .priority = 1, /* let this called before broken drm_fb_helper */
74 };
75
76
77 static acpi_status
pvpanic_walk_resources(struct acpi_resource * res,void * context)78 pvpanic_walk_resources(struct acpi_resource *res, void *context)
79 {
80 switch (res->type) {
81 case ACPI_RESOURCE_TYPE_END_TAG:
82 return AE_OK;
83
84 case ACPI_RESOURCE_TYPE_IO:
85 port = res->data.io.minimum;
86 return AE_OK;
87
88 default:
89 return AE_ERROR;
90 }
91 }
92
pvpanic_add(struct acpi_device * device)93 static int pvpanic_add(struct acpi_device *device)
94 {
95 int ret;
96
97 ret = acpi_bus_get_status(device);
98 if (ret < 0)
99 return ret;
100
101 if (!device->status.enabled || !device->status.functional)
102 return -ENODEV;
103
104 acpi_walk_resources(device->handle, METHOD_NAME__CRS,
105 pvpanic_walk_resources, NULL);
106
107 if (!port)
108 return -ENODEV;
109
110 atomic_notifier_chain_register(&panic_notifier_list,
111 &pvpanic_panic_nb);
112
113 return 0;
114 }
115
pvpanic_remove(struct acpi_device * device)116 static int pvpanic_remove(struct acpi_device *device)
117 {
118
119 atomic_notifier_chain_unregister(&panic_notifier_list,
120 &pvpanic_panic_nb);
121 return 0;
122 }
123
124 module_acpi_driver(pvpanic_driver);
125
