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d0173278 | 1 | // SPDX-License-Identifier: GPL-2.0 |
c4c28335 GG |
2 | /* |
3 | * NANO7240 SBC Watchdog device driver | |
4 | * | |
5 | * Based on w83877f.c by Scott Jennings, | |
6 | * | |
c4c28335 | 7 | * (c) Copyright 2007 Gilles GIGAN <gilles.gigan@jcu.edu.au> |
c4c28335 GG |
8 | */ |
9 | ||
27c766aa JP |
10 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
11 | ||
c4c28335 GG |
12 | #include <linux/fs.h> |
13 | #include <linux/init.h> | |
14 | #include <linux/ioport.h> | |
15 | #include <linux/jiffies.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/moduleparam.h> | |
18 | #include <linux/miscdevice.h> | |
19 | #include <linux/notifier.h> | |
20 | #include <linux/reboot.h> | |
21 | #include <linux/types.h> | |
22 | #include <linux/watchdog.h> | |
619a8a2b AC |
23 | #include <linux/io.h> |
24 | #include <linux/uaccess.h> | |
60063497 | 25 | #include <linux/atomic.h> |
c4c28335 | 26 | |
c4c28335 GG |
27 | #define SBC7240_ENABLE_PORT 0x443 |
28 | #define SBC7240_DISABLE_PORT 0x043 | |
29 | #define SBC7240_SET_TIMEOUT_PORT SBC7240_ENABLE_PORT | |
30 | #define SBC7240_MAGIC_CHAR 'V' | |
31 | ||
32 | #define SBC7240_TIMEOUT 30 | |
33 | #define SBC7240_MAX_TIMEOUT 255 | |
34 | static int timeout = SBC7240_TIMEOUT; /* in seconds */ | |
35 | module_param(timeout, int, 0); | |
36 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=" | |
37 | __MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default=" | |
38 | __MODULE_STRING(SBC7240_TIMEOUT) ")"); | |
39 | ||
86a1e189 WVS |
40 | static bool nowayout = WATCHDOG_NOWAYOUT; |
41 | module_param(nowayout, bool, 0); | |
c4c28335 GG |
42 | MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file"); |
43 | ||
44 | #define SBC7240_OPEN_STATUS_BIT 0 | |
45 | #define SBC7240_ENABLED_STATUS_BIT 1 | |
46 | #define SBC7240_EXPECT_CLOSE_STATUS_BIT 2 | |
47 | static unsigned long wdt_status; | |
48 | ||
49 | /* | |
50 | * Utility routines | |
51 | */ | |
52 | ||
53 | static void wdt_disable(void) | |
54 | { | |
55 | /* disable the watchdog */ | |
56 | if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) { | |
57 | inb_p(SBC7240_DISABLE_PORT); | |
27c766aa | 58 | pr_info("Watchdog timer is now disabled\n"); |
c4c28335 GG |
59 | } |
60 | } | |
61 | ||
62 | static void wdt_enable(void) | |
63 | { | |
64 | /* enable the watchdog */ | |
65 | if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) { | |
66 | inb_p(SBC7240_ENABLE_PORT); | |
27c766aa | 67 | pr_info("Watchdog timer is now enabled\n"); |
c4c28335 GG |
68 | } |
69 | } | |
70 | ||
71 | static int wdt_set_timeout(int t) | |
72 | { | |
73 | if (t < 1 || t > SBC7240_MAX_TIMEOUT) { | |
27c766aa | 74 | pr_err("timeout value must be 1<=x<=%d\n", SBC7240_MAX_TIMEOUT); |
c4c28335 GG |
75 | return -1; |
76 | } | |
77 | /* set the timeout */ | |
78 | outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT); | |
79 | timeout = t; | |
27c766aa | 80 | pr_info("timeout set to %d seconds\n", t); |
c4c28335 GG |
81 | return 0; |
82 | } | |
83 | ||
84 | /* Whack the dog */ | |
85 | static inline void wdt_keepalive(void) | |
86 | { | |
87 | if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) | |
88 | inb_p(SBC7240_ENABLE_PORT); | |
89 | } | |
90 | ||
91 | /* | |
92 | * /dev/watchdog handling | |
93 | */ | |
94 | static ssize_t fop_write(struct file *file, const char __user *buf, | |
95 | size_t count, loff_t *ppos) | |
96 | { | |
97 | size_t i; | |
98 | char c; | |
99 | ||
100 | if (count) { | |
101 | if (!nowayout) { | |
102 | clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, | |
103 | &wdt_status); | |
104 | ||
105 | /* is there a magic char ? */ | |
106 | for (i = 0; i != count; i++) { | |
107 | if (get_user(c, buf + i)) | |
108 | return -EFAULT; | |
109 | if (c == SBC7240_MAGIC_CHAR) { | |
110 | set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, | |
111 | &wdt_status); | |
112 | break; | |
113 | } | |
114 | } | |
115 | } | |
116 | ||
117 | wdt_keepalive(); | |
118 | } | |
119 | ||
120 | return count; | |
121 | } | |
122 | ||
123 | static int fop_open(struct inode *inode, struct file *file) | |
124 | { | |
125 | if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status)) | |
126 | return -EBUSY; | |
127 | ||
128 | wdt_enable(); | |
129 | ||
c5bf68fe | 130 | return stream_open(inode, file); |
c4c28335 GG |
131 | } |
132 | ||
133 | static int fop_close(struct inode *inode, struct file *file) | |
134 | { | |
135 | if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status) | |
136 | || !nowayout) { | |
137 | wdt_disable(); | |
138 | } else { | |
27c766aa | 139 | pr_crit("Unexpected close, not stopping watchdog!\n"); |
c4c28335 GG |
140 | wdt_keepalive(); |
141 | } | |
142 | ||
143 | clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status); | |
144 | return 0; | |
145 | } | |
146 | ||
619a8a2b | 147 | static const struct watchdog_info ident = { |
c4c28335 GG |
148 | .options = WDIOF_KEEPALIVEPING| |
149 | WDIOF_SETTIMEOUT| | |
150 | WDIOF_MAGICCLOSE, | |
151 | .firmware_version = 1, | |
152 | .identity = "SBC7240", | |
153 | }; | |
154 | ||
155 | ||
619a8a2b | 156 | static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
c4c28335 GG |
157 | { |
158 | switch (cmd) { | |
159 | case WDIOC_GETSUPPORT: | |
619a8a2b AC |
160 | return copy_to_user((void __user *)arg, &ident, sizeof(ident)) |
161 | ? -EFAULT : 0; | |
c4c28335 GG |
162 | case WDIOC_GETSTATUS: |
163 | case WDIOC_GETBOOTSTATUS: | |
164 | return put_user(0, (int __user *)arg); | |
0c06090c WVS |
165 | case WDIOC_SETOPTIONS: |
166 | { | |
167 | int options; | |
168 | int retval = -EINVAL; | |
c4c28335 | 169 | |
0c06090c WVS |
170 | if (get_user(options, (int __user *)arg)) |
171 | return -EFAULT; | |
c4c28335 | 172 | |
0c06090c WVS |
173 | if (options & WDIOS_DISABLECARD) { |
174 | wdt_disable(); | |
175 | retval = 0; | |
176 | } | |
c4c28335 | 177 | |
0c06090c WVS |
178 | if (options & WDIOS_ENABLECARD) { |
179 | wdt_enable(); | |
180 | retval = 0; | |
c4c28335 | 181 | } |
c4c28335 | 182 | |
0c06090c WVS |
183 | return retval; |
184 | } | |
185 | case WDIOC_KEEPALIVE: | |
186 | wdt_keepalive(); | |
187 | return 0; | |
188 | case WDIOC_SETTIMEOUT: | |
189 | { | |
190 | int new_timeout; | |
c4c28335 | 191 | |
0c06090c WVS |
192 | if (get_user(new_timeout, (int __user *)arg)) |
193 | return -EFAULT; | |
c4c28335 | 194 | |
0c06090c WVS |
195 | if (wdt_set_timeout(new_timeout)) |
196 | return -EINVAL; | |
197 | ||
198 | /* Fall through */ | |
199 | } | |
c4c28335 GG |
200 | case WDIOC_GETTIMEOUT: |
201 | return put_user(timeout, (int __user *)arg); | |
202 | default: | |
203 | return -ENOTTY; | |
204 | } | |
205 | } | |
206 | ||
207 | static const struct file_operations wdt_fops = { | |
208 | .owner = THIS_MODULE, | |
209 | .llseek = no_llseek, | |
210 | .write = fop_write, | |
211 | .open = fop_open, | |
212 | .release = fop_close, | |
619a8a2b | 213 | .unlocked_ioctl = fop_ioctl, |
c4c28335 GG |
214 | }; |
215 | ||
216 | static struct miscdevice wdt_miscdev = { | |
217 | .minor = WATCHDOG_MINOR, | |
218 | .name = "watchdog", | |
219 | .fops = &wdt_fops, | |
220 | }; | |
221 | ||
222 | /* | |
223 | * Notifier for system down | |
224 | */ | |
225 | ||
226 | static int wdt_notify_sys(struct notifier_block *this, unsigned long code, | |
227 | void *unused) | |
228 | { | |
229 | if (code == SYS_DOWN || code == SYS_HALT) | |
230 | wdt_disable(); | |
231 | return NOTIFY_DONE; | |
232 | } | |
233 | ||
234 | static struct notifier_block wdt_notifier = { | |
235 | .notifier_call = wdt_notify_sys, | |
236 | }; | |
237 | ||
238 | static void __exit sbc7240_wdt_unload(void) | |
239 | { | |
27c766aa | 240 | pr_info("Removing watchdog\n"); |
c4c28335 GG |
241 | misc_deregister(&wdt_miscdev); |
242 | ||
243 | unregister_reboot_notifier(&wdt_notifier); | |
244 | release_region(SBC7240_ENABLE_PORT, 1); | |
245 | } | |
246 | ||
247 | static int __init sbc7240_wdt_init(void) | |
248 | { | |
249 | int rc = -EBUSY; | |
250 | ||
251 | if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) { | |
27c766aa | 252 | pr_err("I/O address 0x%04x already in use\n", |
c4c28335 GG |
253 | SBC7240_ENABLE_PORT); |
254 | rc = -EIO; | |
255 | goto err_out; | |
256 | } | |
257 | ||
258 | /* The IO port 0x043 used to disable the watchdog | |
259 | * is already claimed by the system timer, so we | |
25985edc | 260 | * can't request_region() it ...*/ |
c4c28335 GG |
261 | |
262 | if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) { | |
263 | timeout = SBC7240_TIMEOUT; | |
27c766aa JP |
264 | pr_info("timeout value must be 1<=x<=%d, using %d\n", |
265 | SBC7240_MAX_TIMEOUT, timeout); | |
c4c28335 GG |
266 | } |
267 | wdt_set_timeout(timeout); | |
268 | wdt_disable(); | |
269 | ||
270 | rc = register_reboot_notifier(&wdt_notifier); | |
271 | if (rc) { | |
27c766aa | 272 | pr_err("cannot register reboot notifier (err=%d)\n", rc); |
c4c28335 GG |
273 | goto err_out_region; |
274 | } | |
275 | ||
276 | rc = misc_register(&wdt_miscdev); | |
277 | if (rc) { | |
27c766aa | 278 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
c4c28335 GG |
279 | wdt_miscdev.minor, rc); |
280 | goto err_out_reboot_notifier; | |
281 | } | |
282 | ||
27c766aa JP |
283 | pr_info("Watchdog driver for SBC7240 initialised (nowayout=%d)\n", |
284 | nowayout); | |
c4c28335 GG |
285 | |
286 | return 0; | |
287 | ||
288 | err_out_reboot_notifier: | |
289 | unregister_reboot_notifier(&wdt_notifier); | |
290 | err_out_region: | |
291 | release_region(SBC7240_ENABLE_PORT, 1); | |
292 | err_out: | |
293 | return rc; | |
294 | } | |
295 | ||
296 | module_init(sbc7240_wdt_init); | |
297 | module_exit(sbc7240_wdt_unload); | |
298 | ||
299 | MODULE_AUTHOR("Gilles Gigan"); | |
300 | MODULE_DESCRIPTION("Watchdog device driver for single board" | |
301 | " computers EPIC Nano 7240 from iEi"); | |
302 | MODULE_LICENSE("GPL"); |