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3a5f9000 DT |
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 | ||
3a5f9000 | 28 | |
86a1e189 | 29 | static bool nowayout = WATCHDOG_NOWAYOUT; |
3a5f9000 DT |
30 | static unsigned int margin = 60; /* (secs) Default is 1 minute */ |
31 | static unsigned long wdt_status; | |
322af98c | 32 | static DEFINE_MUTEX(wdt_lock); |
3a5f9000 DT |
33 | |
34 | #define WDT_IN_USE 0 | |
35 | #define WDT_OK_TO_CLOSE 1 | |
36 | ||
37 | #define COMMAND_PORT 0x4c | |
38 | #define DATA_PORT 0x48 | |
39 | ||
40 | #define IFACE_ON_COMMAND 1 | |
41 | #define REBOOT_COMMAND 2 | |
42 | ||
5f3b2756 | 43 | #define WATCHDOG_NAME "SBC-FITPC2 Watchdog" |
3a5f9000 DT |
44 | |
45 | static void wdt_send_data(unsigned char command, unsigned char data) | |
46 | { | |
3a5f9000 | 47 | outb(data, DATA_PORT); |
ef39a1bf | 48 | msleep(200); |
fcf1dd7e DT |
49 | outb(command, COMMAND_PORT); |
50 | msleep(100); | |
3a5f9000 DT |
51 | } |
52 | ||
53 | static void wdt_enable(void) | |
54 | { | |
322af98c | 55 | mutex_lock(&wdt_lock); |
3a5f9000 DT |
56 | wdt_send_data(IFACE_ON_COMMAND, 1); |
57 | wdt_send_data(REBOOT_COMMAND, margin); | |
322af98c | 58 | mutex_unlock(&wdt_lock); |
3a5f9000 DT |
59 | } |
60 | ||
61 | static void wdt_disable(void) | |
62 | { | |
322af98c | 63 | mutex_lock(&wdt_lock); |
3a5f9000 DT |
64 | wdt_send_data(IFACE_ON_COMMAND, 0); |
65 | wdt_send_data(REBOOT_COMMAND, 0); | |
322af98c | 66 | mutex_unlock(&wdt_lock); |
3a5f9000 DT |
67 | } |
68 | ||
69 | static int fitpc2_wdt_open(struct inode *inode, struct file *file) | |
70 | { | |
71 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) | |
72 | return -EBUSY; | |
73 | ||
74 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
75 | ||
76 | wdt_enable(); | |
77 | ||
c5bf68fe | 78 | return stream_open(inode, file); |
3a5f9000 DT |
79 | } |
80 | ||
81 | static ssize_t fitpc2_wdt_write(struct file *file, const char *data, | |
82 | size_t len, loff_t *ppos) | |
83 | { | |
84 | size_t i; | |
85 | ||
86 | if (!len) | |
87 | return 0; | |
88 | ||
89 | if (nowayout) { | |
90 | len = 0; | |
91 | goto out; | |
92 | } | |
93 | ||
94 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
95 | ||
96 | for (i = 0; i != len; i++) { | |
97 | char c; | |
98 | ||
99 | if (get_user(c, data + i)) | |
100 | return -EFAULT; | |
101 | ||
102 | if (c == 'V') | |
103 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
104 | } | |
105 | ||
106 | out: | |
107 | wdt_enable(); | |
108 | ||
109 | return len; | |
110 | } | |
111 | ||
112 | ||
42747d71 | 113 | static const struct watchdog_info ident = { |
3a5f9000 DT |
114 | .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | |
115 | WDIOF_KEEPALIVEPING, | |
116 | .identity = WATCHDOG_NAME, | |
117 | }; | |
118 | ||
119 | ||
120 | static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd, | |
121 | unsigned long arg) | |
122 | { | |
123 | int ret = -ENOTTY; | |
124 | int time; | |
125 | ||
126 | switch (cmd) { | |
127 | case WDIOC_GETSUPPORT: | |
128 | ret = copy_to_user((struct watchdog_info *)arg, &ident, | |
129 | sizeof(ident)) ? -EFAULT : 0; | |
130 | break; | |
131 | ||
132 | case WDIOC_GETSTATUS: | |
133 | ret = put_user(0, (int *)arg); | |
134 | break; | |
135 | ||
136 | case WDIOC_GETBOOTSTATUS: | |
137 | ret = put_user(0, (int *)arg); | |
138 | break; | |
139 | ||
140 | case WDIOC_KEEPALIVE: | |
141 | wdt_enable(); | |
142 | ret = 0; | |
143 | break; | |
144 | ||
145 | case WDIOC_SETTIMEOUT: | |
146 | ret = get_user(time, (int *)arg); | |
147 | if (ret) | |
148 | break; | |
149 | ||
150 | if (time < 31 || time > 255) { | |
151 | ret = -EINVAL; | |
152 | break; | |
153 | } | |
154 | ||
155 | margin = time; | |
156 | wdt_enable(); | |
157 | /* Fall through */ | |
158 | ||
159 | case WDIOC_GETTIMEOUT: | |
160 | ret = put_user(margin, (int *)arg); | |
161 | break; | |
162 | } | |
163 | ||
164 | return ret; | |
165 | } | |
166 | ||
167 | static int fitpc2_wdt_release(struct inode *inode, struct file *file) | |
168 | { | |
169 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) { | |
170 | wdt_disable(); | |
171 | pr_info("Device disabled\n"); | |
172 | } else { | |
27c766aa | 173 | pr_warn("Device closed unexpectedly - timer will not stop\n"); |
3a5f9000 DT |
174 | wdt_enable(); |
175 | } | |
176 | ||
177 | clear_bit(WDT_IN_USE, &wdt_status); | |
178 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
179 | ||
180 | return 0; | |
181 | } | |
182 | ||
183 | ||
184 | static const struct file_operations fitpc2_wdt_fops = { | |
185 | .owner = THIS_MODULE, | |
186 | .llseek = no_llseek, | |
187 | .write = fitpc2_wdt_write, | |
188 | .unlocked_ioctl = fitpc2_wdt_ioctl, | |
189 | .open = fitpc2_wdt_open, | |
190 | .release = fitpc2_wdt_release, | |
191 | }; | |
192 | ||
193 | static struct miscdevice fitpc2_wdt_miscdev = { | |
194 | .minor = WATCHDOG_MINOR, | |
195 | .name = "watchdog", | |
196 | .fops = &fitpc2_wdt_fops, | |
197 | }; | |
198 | ||
199 | static int __init fitpc2_wdt_init(void) | |
200 | { | |
201 | int err; | |
d4065775 | 202 | const char *brd_name; |
3a5f9000 | 203 | |
d4065775 JS |
204 | brd_name = dmi_get_system_info(DMI_BOARD_NAME); |
205 | ||
206 | if (!brd_name || !strstr(brd_name, "SBC-FITPC2")) | |
3a5f9000 | 207 | return -ENODEV; |
ef39a1bf | 208 | |
d4065775 | 209 | pr_info("%s found\n", brd_name); |
3a5f9000 DT |
210 | |
211 | if (!request_region(COMMAND_PORT, 1, WATCHDOG_NAME)) { | |
212 | pr_err("I/O address 0x%04x already in use\n", COMMAND_PORT); | |
213 | return -EIO; | |
214 | } | |
215 | ||
216 | if (!request_region(DATA_PORT, 1, WATCHDOG_NAME)) { | |
217 | pr_err("I/O address 0x%04x already in use\n", DATA_PORT); | |
218 | err = -EIO; | |
219 | goto err_data_port; | |
220 | } | |
221 | ||
222 | if (margin < 31 || margin > 255) { | |
27c766aa JP |
223 | pr_err("margin must be in range 31 - 255 seconds, you tried to set %d\n", |
224 | margin); | |
3a5f9000 DT |
225 | err = -EINVAL; |
226 | goto err_margin; | |
227 | } | |
228 | ||
229 | err = misc_register(&fitpc2_wdt_miscdev); | |
1efd374d | 230 | if (err) { |
3a5f9000 | 231 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
27c766aa | 232 | WATCHDOG_MINOR, err); |
3a5f9000 DT |
233 | goto err_margin; |
234 | } | |
235 | ||
236 | return 0; | |
237 | ||
238 | err_margin: | |
239 | release_region(DATA_PORT, 1); | |
240 | err_data_port: | |
241 | release_region(COMMAND_PORT, 1); | |
242 | ||
243 | return err; | |
244 | } | |
245 | ||
246 | static void __exit fitpc2_wdt_exit(void) | |
247 | { | |
248 | misc_deregister(&fitpc2_wdt_miscdev); | |
249 | release_region(DATA_PORT, 1); | |
250 | release_region(COMMAND_PORT, 1); | |
251 | } | |
252 | ||
253 | module_init(fitpc2_wdt_init); | |
254 | module_exit(fitpc2_wdt_exit); | |
255 | ||
256 | MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>"); | |
257 | MODULE_DESCRIPTION("SBC-FITPC2 Watchdog"); | |
258 | ||
259 | module_param(margin, int, 0); | |
260 | MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)"); | |
261 | ||
86a1e189 | 262 | module_param(nowayout, bool, 0); |
3a5f9000 DT |
263 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); |
264 | ||
265 | MODULE_LICENSE("GPL"); |