[WATCHDOG] sbc_fitpc2_wdt: fix I/O space access technique.
[linux-2.6.git] / drivers / watchdog / sbc_fitpc2_wdt.c
1 /*
2  * Watchdog driver for SBC-FITPC2 board
3  *
4  * Author: Denis Turischev <denis@compulab.co.il>
5  *
6  * Adapted from the IXP2000 watchdog driver by Deepak Saxena.
7  *
8  * This file is licensed under  the terms of the GNU General Public
9  * License version 2. This program is licensed "as is" without any
10  * warranty of any kind, whether express or implied.
11  */
12
13 #define pr_fmt(fmt) KBUILD_MODNAME " WATCHDOG: " fmt
14
15 #include <linux/module.h>
16 #include <linux/types.h>
17 #include <linux/miscdevice.h>
18 #include <linux/watchdog.h>
19 #include <linux/ioport.h>
20 #include <linux/delay.h>
21 #include <linux/fs.h>
22 #include <linux/init.h>
23 #include <linux/moduleparam.h>
24 #include <linux/dmi.h>
25 #include <linux/io.h>
26 #include <linux/uaccess.h>
27
28 #include <asm/system.h>
29
30 static int nowayout = WATCHDOG_NOWAYOUT;
31 static unsigned int margin = 60;        /* (secs) Default is 1 minute */
32 static unsigned long wdt_status;
33 static DEFINE_SPINLOCK(wdt_lock);
34
35 #define WDT_IN_USE              0
36 #define WDT_OK_TO_CLOSE         1
37
38 #define COMMAND_PORT            0x4c
39 #define DATA_PORT               0x48
40
41 #define IFACE_ON_COMMAND        1
42 #define REBOOT_COMMAND          2
43
44 #define WATCHDOG_NAME           "SBC-FITPC2 Watchdog"
45
46 static void wdt_send_data(unsigned char command, unsigned char data)
47 {
48         outb(command, COMMAND_PORT);
49         msleep(100);
50         outb(data, DATA_PORT);
51         msleep(200);
52 }
53
54 static void wdt_enable(void)
55 {
56         spin_lock(&wdt_lock);
57         wdt_send_data(IFACE_ON_COMMAND, 1);
58         wdt_send_data(REBOOT_COMMAND, margin);
59         spin_unlock(&wdt_lock);
60 }
61
62 static void wdt_disable(void)
63 {
64         spin_lock(&wdt_lock);
65         wdt_send_data(IFACE_ON_COMMAND, 0);
66         wdt_send_data(REBOOT_COMMAND, 0);
67         spin_unlock(&wdt_lock);
68 }
69
70 static int fitpc2_wdt_open(struct inode *inode, struct file *file)
71 {
72         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
73                 return -EBUSY;
74
75         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
76
77         wdt_enable();
78
79         return nonseekable_open(inode, file);
80 }
81
82 static ssize_t fitpc2_wdt_write(struct file *file, const char *data,
83                                                 size_t len, loff_t *ppos)
84 {
85         size_t i;
86
87         if (!len)
88                 return 0;
89
90         if (nowayout) {
91                 len = 0;
92                 goto out;
93         }
94
95         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
96
97         for (i = 0; i != len; i++) {
98                 char c;
99
100                 if (get_user(c, data + i))
101                         return -EFAULT;
102
103                 if (c == 'V')
104                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
105         }
106
107 out:
108         wdt_enable();
109
110         return len;
111 }
112
113
114 static struct watchdog_info ident = {
115         .options        = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
116                                 WDIOF_KEEPALIVEPING,
117         .identity       = WATCHDOG_NAME,
118 };
119
120
121 static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd,
122                                                         unsigned long arg)
123 {
124         int ret = -ENOTTY;
125         int time;
126
127         switch (cmd) {
128         case WDIOC_GETSUPPORT:
129                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
130                                    sizeof(ident)) ? -EFAULT : 0;
131                 break;
132
133         case WDIOC_GETSTATUS:
134                 ret = put_user(0, (int *)arg);
135                 break;
136
137         case WDIOC_GETBOOTSTATUS:
138                 ret = put_user(0, (int *)arg);
139                 break;
140
141         case WDIOC_KEEPALIVE:
142                 wdt_enable();
143                 ret = 0;
144                 break;
145
146         case WDIOC_SETTIMEOUT:
147                 ret = get_user(time, (int *)arg);
148                 if (ret)
149                         break;
150
151                 if (time < 31 || time > 255) {
152                         ret = -EINVAL;
153                         break;
154                 }
155
156                 margin = time;
157                 wdt_enable();
158                 /* Fall through */
159
160         case WDIOC_GETTIMEOUT:
161                 ret = put_user(margin, (int *)arg);
162                 break;
163         }
164
165         return ret;
166 }
167
168 static int fitpc2_wdt_release(struct inode *inode, struct file *file)
169 {
170         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
171                 wdt_disable();
172                 pr_info("Device disabled\n");
173         } else {
174                 pr_warning("Device closed unexpectedly -"
175                         " timer will not stop\n");
176                 wdt_enable();
177         }
178
179         clear_bit(WDT_IN_USE, &wdt_status);
180         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
181
182         return 0;
183 }
184
185
186 static const struct file_operations fitpc2_wdt_fops = {
187         .owner          = THIS_MODULE,
188         .llseek         = no_llseek,
189         .write          = fitpc2_wdt_write,
190         .unlocked_ioctl = fitpc2_wdt_ioctl,
191         .open           = fitpc2_wdt_open,
192         .release        = fitpc2_wdt_release,
193 };
194
195 static struct miscdevice fitpc2_wdt_miscdev = {
196         .minor          = WATCHDOG_MINOR,
197         .name           = "watchdog",
198         .fops           = &fitpc2_wdt_fops,
199 };
200
201 static int __init fitpc2_wdt_init(void)
202 {
203         int err;
204
205         if (!strstr(dmi_get_system_info(DMI_BOARD_NAME), "SBC-FITPC2"))
206                 return -ENODEV;
207
208         pr_info("%s found\n", dmi_get_system_info(DMI_BOARD_NAME));
209
210         if (!request_region(COMMAND_PORT, 1, WATCHDOG_NAME)) {
211                 pr_err("I/O address 0x%04x already in use\n", COMMAND_PORT);
212                 return -EIO;
213         }
214
215         if (!request_region(DATA_PORT, 1, WATCHDOG_NAME)) {
216                 pr_err("I/O address 0x%04x already in use\n", DATA_PORT);
217                 err = -EIO;
218                 goto err_data_port;
219         }
220
221         if (margin < 31 || margin > 255) {
222                 pr_err("margin must be in range 31 - 255"
223                        " seconds, you tried to set %d\n", margin);
224                 err = -EINVAL;
225                 goto err_margin;
226         }
227
228         err = misc_register(&fitpc2_wdt_miscdev);
229         if (err) {
230                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
231                                                         WATCHDOG_MINOR, err);
232                 goto err_margin;
233         }
234
235         return 0;
236
237 err_margin:
238         release_region(DATA_PORT, 1);
239 err_data_port:
240         release_region(COMMAND_PORT, 1);
241
242         return err;
243 }
244
245 static void __exit fitpc2_wdt_exit(void)
246 {
247         misc_deregister(&fitpc2_wdt_miscdev);
248         release_region(DATA_PORT, 1);
249         release_region(COMMAND_PORT, 1);
250 }
251
252 module_init(fitpc2_wdt_init);
253 module_exit(fitpc2_wdt_exit);
254
255 MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
256 MODULE_DESCRIPTION("SBC-FITPC2 Watchdog");
257
258 module_param(margin, int, 0);
259 MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
260
261 module_param(nowayout, int, 0);
262 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
263
264 MODULE_LICENSE("GPL");
265 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
266