dab09d3f6307be4e5f38d734f3c10e77653b40a2
[linux-2.6.git] / drivers / acpi / event.c
1 /*
2  * event.c - exporting ACPI events via procfs
3  *
4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6  *
7  */
8
9 #include <linux/spinlock.h>
10 #include <linux/proc_fs.h>
11 #include <linux/init.h>
12 #include <linux/poll.h>
13 #include <acpi/acpi_drivers.h>
14
15 #define _COMPONENT              ACPI_SYSTEM_COMPONENT
16 ACPI_MODULE_NAME("event")
17
18 /* Global vars for handling event proc entry */
19 static DEFINE_SPINLOCK(acpi_system_event_lock);
20 int event_is_open = 0;
21 extern struct list_head acpi_bus_event_list;
22 extern wait_queue_head_t acpi_bus_event_queue;
23
24 static int acpi_system_open_event(struct inode *inode, struct file *file)
25 {
26         spin_lock_irq(&acpi_system_event_lock);
27
28         if (event_is_open)
29                 goto out_busy;
30
31         event_is_open = 1;
32
33         spin_unlock_irq(&acpi_system_event_lock);
34         return 0;
35
36       out_busy:
37         spin_unlock_irq(&acpi_system_event_lock);
38         return -EBUSY;
39 }
40
41 static ssize_t
42 acpi_system_read_event(struct file *file, char __user * buffer, size_t count,
43                        loff_t * ppos)
44 {
45         int result = 0;
46         struct acpi_bus_event event;
47         static char str[ACPI_MAX_STRING];
48         static int chars_remaining = 0;
49         static char *ptr;
50
51         ACPI_FUNCTION_TRACE("acpi_system_read_event");
52
53         if (!chars_remaining) {
54                 memset(&event, 0, sizeof(struct acpi_bus_event));
55
56                 if ((file->f_flags & O_NONBLOCK)
57                     && (list_empty(&acpi_bus_event_list)))
58                         return_VALUE(-EAGAIN);
59
60                 result = acpi_bus_receive_event(&event);
61                 if (result)
62                         return_VALUE(result);
63
64                 chars_remaining = sprintf(str, "%s %s %08x %08x\n",
65                                           event.device_class ? event.
66                                           device_class : "<unknown>",
67                                           event.bus_id ? event.
68                                           bus_id : "<unknown>", event.type,
69                                           event.data);
70                 ptr = str;
71         }
72
73         if (chars_remaining < count) {
74                 count = chars_remaining;
75         }
76
77         if (copy_to_user(buffer, ptr, count))
78                 return_VALUE(-EFAULT);
79
80         *ppos += count;
81         chars_remaining -= count;
82         ptr += count;
83
84         return_VALUE(count);
85 }
86
87 static int acpi_system_close_event(struct inode *inode, struct file *file)
88 {
89         spin_lock_irq(&acpi_system_event_lock);
90         event_is_open = 0;
91         spin_unlock_irq(&acpi_system_event_lock);
92         return 0;
93 }
94
95 static unsigned int acpi_system_poll_event(struct file *file, poll_table * wait)
96 {
97         poll_wait(file, &acpi_bus_event_queue, wait);
98         if (!list_empty(&acpi_bus_event_list))
99                 return POLLIN | POLLRDNORM;
100         return 0;
101 }
102
103 static struct file_operations acpi_system_event_ops = {
104         .open = acpi_system_open_event,
105         .read = acpi_system_read_event,
106         .release = acpi_system_close_event,
107         .poll = acpi_system_poll_event,
108 };
109
110 static int __init acpi_event_init(void)
111 {
112         struct proc_dir_entry *entry;
113         int error = 0;
114
115         ACPI_FUNCTION_TRACE("acpi_event_init");
116
117         if (acpi_disabled)
118                 return_VALUE(0);
119
120         /* 'event' [R] */
121         entry = create_proc_entry("event", S_IRUSR, acpi_root_dir);
122         if (entry)
123                 entry->proc_fops = &acpi_system_event_ops;
124         else {
125                 error = -ENODEV;
126         }
127         return_VALUE(error);
128 }
129
130 subsys_initcall(acpi_event_init);