[PATCH] Document online io scheduler switching
[linux-2.6] / drivers / acpi / system.c
1 /*
2  *  acpi_system.c - ACPI System Driver ($Revision: 63 $)
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  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License as published by
11  *  the Free Software Foundation; either version 2 of the License, or (at
12  *  your option) any later version.
13  *
14  *  This program is distributed in the hope that it will be useful, but
15  *  WITHOUT ANY WARRANTY; without even the implied warranty of
16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17  *  General Public License for more details.
18  *
19  *  You should have received a copy of the GNU General Public License along
20  *  with this program; if not, write to the Free Software Foundation, Inc.,
21  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
22  *
23  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
24  */
25
26 #include <linux/proc_fs.h>
27 #include <linux/seq_file.h>
28 #include <linux/init.h>
29 #include <asm/uaccess.h>
30
31 #include <acpi/acpi_drivers.h>
32
33 #define _COMPONENT              ACPI_SYSTEM_COMPONENT
34 ACPI_MODULE_NAME("acpi_system")
35 #define ACPI_SYSTEM_CLASS               "system"
36 #define ACPI_SYSTEM_DRIVER_NAME         "ACPI System Driver"
37 #define ACPI_SYSTEM_DEVICE_NAME         "System"
38 #define ACPI_SYSTEM_FILE_INFO           "info"
39 #define ACPI_SYSTEM_FILE_EVENT          "event"
40 #define ACPI_SYSTEM_FILE_DSDT           "dsdt"
41 #define ACPI_SYSTEM_FILE_FADT           "fadt"
42 extern FADT_DESCRIPTOR acpi_fadt;
43
44 /* --------------------------------------------------------------------------
45                               FS Interface (/proc)
46    -------------------------------------------------------------------------- */
47
48 static int acpi_system_read_info(struct seq_file *seq, void *offset)
49 {
50         ACPI_FUNCTION_TRACE("acpi_system_read_info");
51
52         seq_printf(seq, "version:                 %x\n", ACPI_CA_VERSION);
53         return_VALUE(0);
54 }
55
56 static int acpi_system_info_open_fs(struct inode *inode, struct file *file)
57 {
58         return single_open(file, acpi_system_read_info, PDE(inode)->data);
59 }
60
61 static struct file_operations acpi_system_info_ops = {
62         .open = acpi_system_info_open_fs,
63         .read = seq_read,
64         .llseek = seq_lseek,
65         .release = single_release,
66 };
67
68 static ssize_t acpi_system_read_dsdt(struct file *, char __user *, size_t,
69                                      loff_t *);
70
71 static struct file_operations acpi_system_dsdt_ops = {
72         .read = acpi_system_read_dsdt,
73 };
74
75 static ssize_t
76 acpi_system_read_dsdt(struct file *file,
77                       char __user * buffer, size_t count, loff_t * ppos)
78 {
79         acpi_status status = AE_OK;
80         struct acpi_buffer dsdt = { ACPI_ALLOCATE_BUFFER, NULL };
81         ssize_t res;
82
83         ACPI_FUNCTION_TRACE("acpi_system_read_dsdt");
84
85         status = acpi_get_table(ACPI_TABLE_DSDT, 1, &dsdt);
86         if (ACPI_FAILURE(status))
87                 return_VALUE(-ENODEV);
88
89         res = simple_read_from_buffer(buffer, count, ppos,
90                                       dsdt.pointer, dsdt.length);
91         acpi_os_free(dsdt.pointer);
92
93         return_VALUE(res);
94 }
95
96 static ssize_t acpi_system_read_fadt(struct file *, char __user *, size_t,
97                                      loff_t *);
98
99 static struct file_operations acpi_system_fadt_ops = {
100         .read = acpi_system_read_fadt,
101 };
102
103 static ssize_t
104 acpi_system_read_fadt(struct file *file,
105                       char __user * buffer, size_t count, loff_t * ppos)
106 {
107         acpi_status status = AE_OK;
108         struct acpi_buffer fadt = { ACPI_ALLOCATE_BUFFER, NULL };
109         ssize_t res;
110
111         ACPI_FUNCTION_TRACE("acpi_system_read_fadt");
112
113         status = acpi_get_table(ACPI_TABLE_FADT, 1, &fadt);
114         if (ACPI_FAILURE(status))
115                 return_VALUE(-ENODEV);
116
117         res = simple_read_from_buffer(buffer, count, ppos,
118                                       fadt.pointer, fadt.length);
119         acpi_os_free(fadt.pointer);
120
121         return_VALUE(res);
122 }
123
124 static int __init acpi_system_init(void)
125 {
126         struct proc_dir_entry *entry;
127         int error = 0;
128         char *name;
129
130         ACPI_FUNCTION_TRACE("acpi_system_init");
131
132         if (acpi_disabled)
133                 return_VALUE(0);
134
135         /* 'info' [R] */
136         name = ACPI_SYSTEM_FILE_INFO;
137         entry = create_proc_entry(name, S_IRUGO, acpi_root_dir);
138         if (!entry)
139                 goto Error;
140         else {
141                 entry->proc_fops = &acpi_system_info_ops;
142         }
143
144         /* 'dsdt' [R] */
145         name = ACPI_SYSTEM_FILE_DSDT;
146         entry = create_proc_entry(name, S_IRUSR, acpi_root_dir);
147         if (entry)
148                 entry->proc_fops = &acpi_system_dsdt_ops;
149         else
150                 goto Error;
151
152         /* 'fadt' [R] */
153         name = ACPI_SYSTEM_FILE_FADT;
154         entry = create_proc_entry(name, S_IRUSR, acpi_root_dir);
155         if (entry)
156                 entry->proc_fops = &acpi_system_fadt_ops;
157         else
158                 goto Error;
159
160       Done:
161         return_VALUE(error);
162
163       Error:
164         ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
165                           "Unable to create '%s' proc fs entry\n", name));
166
167         remove_proc_entry(ACPI_SYSTEM_FILE_FADT, acpi_root_dir);
168         remove_proc_entry(ACPI_SYSTEM_FILE_DSDT, acpi_root_dir);
169         remove_proc_entry(ACPI_SYSTEM_FILE_INFO, acpi_root_dir);
170
171         error = -EFAULT;
172         goto Done;
173 }
174
175 subsys_initcall(acpi_system_init);