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
16ACPI_MODULE_NAME("event");
17
18/* Global vars for handling event proc entry */
19static DEFINE_SPINLOCK(acpi_system_event_lock);
20int event_is_open = 0;
21extern struct list_head acpi_bus_event_list;
22extern wait_queue_head_t acpi_bus_event_queue;
23
24static 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
41static ssize_t
42acpi_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
52	if (!chars_remaining) {
53		memset(&event, 0, sizeof(struct acpi_bus_event));
54
55		if ((file->f_flags & O_NONBLOCK)
56		    && (list_empty(&acpi_bus_event_list)))
57			return -EAGAIN;
58
59		result = acpi_bus_receive_event(&event);
60		if (result)
61			return result;
62
63		chars_remaining = sprintf(str, "%s %s %08x %08x\n",
64					  event.device_class ? event.
65					  device_class : "<unknown>",
66					  event.bus_id ? event.
67					  bus_id : "<unknown>", event.type,
68					  event.data);
69		ptr = str;
70	}
71
72	if (chars_remaining < count) {
73		count = chars_remaining;
74	}
75
76	if (copy_to_user(buffer, ptr, count))
77		return -EFAULT;
78
79	*ppos += count;
80	chars_remaining -= count;
81	ptr += count;
82
83	return count;
84}
85
86static int acpi_system_close_event(struct inode *inode, struct file *file)
87{
88	spin_lock_irq(&acpi_system_event_lock);
89	event_is_open = 0;
90	spin_unlock_irq(&acpi_system_event_lock);
91	return 0;
92}
93
94static unsigned int acpi_system_poll_event(struct file *file, poll_table * wait)
95{
96	poll_wait(file, &acpi_bus_event_queue, wait);
97	if (!list_empty(&acpi_bus_event_list))
98		return POLLIN | POLLRDNORM;
99	return 0;
100}
101
102static const struct file_operations acpi_system_event_ops = {
103	.open = acpi_system_open_event,
104	.read = acpi_system_read_event,
105	.release = acpi_system_close_event,
106	.poll = acpi_system_poll_event,
107};
108
109static int __init acpi_event_init(void)
110{
111	struct proc_dir_entry *entry;
112	int error = 0;
113
114
115	if (acpi_disabled)
116		return 0;
117
118	/* 'event' [R] */
119	entry = create_proc_entry("event", S_IRUSR, acpi_root_dir);
120	if (entry)
121		entry->proc_fops = &acpi_system_event_ops;
122	else {
123		error = -ENODEV;
124	}
125	return error;
126}
127
128subsys_initcall(acpi_event_init);
129