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1/*
2 * NANO7240 SBC Watchdog device driver
3 *
4 * Based on w83877f.c by Scott Jennings,
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation;
9 *
10 * Software distributed under the License is distributed on an "AS IS"
11 * basis, WITHOUT WARRANTY OF ANY KIND, either express or
12 * implied. See the License for the specific language governing
13 * rights and limitations under the License.
14 *
15 * (c) Copyright 2007 Gilles GIGAN <gilles.gigan@jcu.edu.au>
16 *
17 */
18
19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#include <linux/fs.h>
22#include <linux/init.h>
23#include <linux/ioport.h>
24#include <linux/jiffies.h>
25#include <linux/module.h>
26#include <linux/moduleparam.h>
27#include <linux/miscdevice.h>
28#include <linux/notifier.h>
29#include <linux/reboot.h>
30#include <linux/types.h>
31#include <linux/watchdog.h>
32#include <linux/io.h>
33#include <linux/uaccess.h>
34#include <linux/atomic.h>
35
36#define SBC7240_ENABLE_PORT 0x443
37#define SBC7240_DISABLE_PORT 0x043
38#define SBC7240_SET_TIMEOUT_PORT SBC7240_ENABLE_PORT
39#define SBC7240_MAGIC_CHAR 'V'
40
41#define SBC7240_TIMEOUT 30
42#define SBC7240_MAX_TIMEOUT 255
43static int timeout = SBC7240_TIMEOUT; /* in seconds */
44module_param(timeout, int, 0);
45MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<="
46 __MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default="
47 __MODULE_STRING(SBC7240_TIMEOUT) ")");
48
49static bool nowayout = WATCHDOG_NOWAYOUT;
50module_param(nowayout, bool, 0);
51MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file");
52
53#define SBC7240_OPEN_STATUS_BIT 0
54#define SBC7240_ENABLED_STATUS_BIT 1
55#define SBC7240_EXPECT_CLOSE_STATUS_BIT 2
56static unsigned long wdt_status;
57
58/*
59 * Utility routines
60 */
61
62static void wdt_disable(void)
63{
64 /* disable the watchdog */
65 if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
66 inb_p(SBC7240_DISABLE_PORT);
67 pr_info("Watchdog timer is now disabled\n");
68 }
69}
70
71static void wdt_enable(void)
72{
73 /* enable the watchdog */
74 if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
75 inb_p(SBC7240_ENABLE_PORT);
76 pr_info("Watchdog timer is now enabled\n");
77 }
78}
79
80static int wdt_set_timeout(int t)
81{
82 if (t < 1 || t > SBC7240_MAX_TIMEOUT) {
83 pr_err("timeout value must be 1<=x<=%d\n", SBC7240_MAX_TIMEOUT);
84 return -1;
85 }
86 /* set the timeout */
87 outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT);
88 timeout = t;
89 pr_info("timeout set to %d seconds\n", t);
90 return 0;
91}
92
93/* Whack the dog */
94static inline void wdt_keepalive(void)
95{
96 if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status))
97 inb_p(SBC7240_ENABLE_PORT);
98}
99
100/*
101 * /dev/watchdog handling
102 */
103static ssize_t fop_write(struct file *file, const char __user *buf,
104 size_t count, loff_t *ppos)
105{
106 size_t i;
107 char c;
108
109 if (count) {
110 if (!nowayout) {
111 clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
112 &wdt_status);
113
114 /* is there a magic char ? */
115 for (i = 0; i != count; i++) {
116 if (get_user(c, buf + i))
117 return -EFAULT;
118 if (c == SBC7240_MAGIC_CHAR) {
119 set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
120 &wdt_status);
121 break;
122 }
123 }
124 }
125
126 wdt_keepalive();
127 }
128
129 return count;
130}
131
132static int fop_open(struct inode *inode, struct file *file)
133{
134 if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status))
135 return -EBUSY;
136
137 wdt_enable();
138
139 return nonseekable_open(inode, file);
140}
141
142static int fop_close(struct inode *inode, struct file *file)
143{
144 if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status)
145 || !nowayout) {
146 wdt_disable();
147 } else {
148 pr_crit("Unexpected close, not stopping watchdog!\n");
149 wdt_keepalive();
150 }
151
152 clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status);
153 return 0;
154}
155
156static const struct watchdog_info ident = {
157 .options = WDIOF_KEEPALIVEPING|
158 WDIOF_SETTIMEOUT|
159 WDIOF_MAGICCLOSE,
160 .firmware_version = 1,
161 .identity = "SBC7240",
162};
163
164
165static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
166{
167 switch (cmd) {
168 case WDIOC_GETSUPPORT:
169 return copy_to_user((void __user *)arg, &ident, sizeof(ident))
170 ? -EFAULT : 0;
171 case WDIOC_GETSTATUS:
172 case WDIOC_GETBOOTSTATUS:
173 return put_user(0, (int __user *)arg);
174 case WDIOC_SETOPTIONS:
175 {
176 int options;
177 int retval = -EINVAL;
178
179 if (get_user(options, (int __user *)arg))
180 return -EFAULT;
181
182 if (options & WDIOS_DISABLECARD) {
183 wdt_disable();
184 retval = 0;
185 }
186
187 if (options & WDIOS_ENABLECARD) {
188 wdt_enable();
189 retval = 0;
190 }
191
192 return retval;
193 }
194 case WDIOC_KEEPALIVE:
195 wdt_keepalive();
196 return 0;
197 case WDIOC_SETTIMEOUT:
198 {
199 int new_timeout;
200
201 if (get_user(new_timeout, (int __user *)arg))
202 return -EFAULT;
203
204 if (wdt_set_timeout(new_timeout))
205 return -EINVAL;
206
207 /* Fall through */
208 }
209 case WDIOC_GETTIMEOUT:
210 return put_user(timeout, (int __user *)arg);
211 default:
212 return -ENOTTY;
213 }
214}
215
216static const struct file_operations wdt_fops = {
217 .owner = THIS_MODULE,
218 .llseek = no_llseek,
219 .write = fop_write,
220 .open = fop_open,
221 .release = fop_close,
222 .unlocked_ioctl = fop_ioctl,
223};
224
225static struct miscdevice wdt_miscdev = {
226 .minor = WATCHDOG_MINOR,
227 .name = "watchdog",
228 .fops = &wdt_fops,
229};
230
231/*
232 * Notifier for system down
233 */
234
235static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
236 void *unused)
237{
238 if (code == SYS_DOWN || code == SYS_HALT)
239 wdt_disable();
240 return NOTIFY_DONE;
241}
242
243static struct notifier_block wdt_notifier = {
244 .notifier_call = wdt_notify_sys,
245};
246
247static void __exit sbc7240_wdt_unload(void)
248{
249 pr_info("Removing watchdog\n");
250 misc_deregister(&wdt_miscdev);
251
252 unregister_reboot_notifier(&wdt_notifier);
253 release_region(SBC7240_ENABLE_PORT, 1);
254}
255
256static int __init sbc7240_wdt_init(void)
257{
258 int rc = -EBUSY;
259
260 if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) {
261 pr_err("I/O address 0x%04x already in use\n",
262 SBC7240_ENABLE_PORT);
263 rc = -EIO;
264 goto err_out;
265 }
266
267 /* The IO port 0x043 used to disable the watchdog
268 * is already claimed by the system timer, so we
269 * can't request_region() it ...*/
270
271 if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) {
272 timeout = SBC7240_TIMEOUT;
273 pr_info("timeout value must be 1<=x<=%d, using %d\n",
274 SBC7240_MAX_TIMEOUT, timeout);
275 }
276 wdt_set_timeout(timeout);
277 wdt_disable();
278
279 rc = register_reboot_notifier(&wdt_notifier);
280 if (rc) {
281 pr_err("cannot register reboot notifier (err=%d)\n", rc);
282 goto err_out_region;
283 }
284
285 rc = misc_register(&wdt_miscdev);
286 if (rc) {
287 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
288 wdt_miscdev.minor, rc);
289 goto err_out_reboot_notifier;
290 }
291
292 pr_info("Watchdog driver for SBC7240 initialised (nowayout=%d)\n",
293 nowayout);
294
295 return 0;
296
297err_out_reboot_notifier:
298 unregister_reboot_notifier(&wdt_notifier);
299err_out_region:
300 release_region(SBC7240_ENABLE_PORT, 1);
301err_out:
302 return rc;
303}
304
305module_init(sbc7240_wdt_init);
306module_exit(sbc7240_wdt_unload);
307
308MODULE_AUTHOR("Gilles Gigan");
309MODULE_DESCRIPTION("Watchdog device driver for single board"
310 " computers EPIC Nano 7240 from iEi");
311MODULE_LICENSE("GPL");
312MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
313
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * NANO7240 SBC Watchdog device driver
4 *
5 * Based on w83877f.c by Scott Jennings,
6 *
7 * (c) Copyright 2007 Gilles GIGAN <gilles.gigan@jcu.edu.au>
8 */
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
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>
23#include <linux/io.h>
24#include <linux/uaccess.h>
25#include <linux/atomic.h>
26
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
34static int timeout = SBC7240_TIMEOUT; /* in seconds */
35module_param(timeout, int, 0);
36MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<="
37 __MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default="
38 __MODULE_STRING(SBC7240_TIMEOUT) ")");
39
40static bool nowayout = WATCHDOG_NOWAYOUT;
41module_param(nowayout, bool, 0);
42MODULE_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
47static unsigned long wdt_status;
48
49/*
50 * Utility routines
51 */
52
53static 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);
58 pr_info("Watchdog timer is now disabled\n");
59 }
60}
61
62static 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);
67 pr_info("Watchdog timer is now enabled\n");
68 }
69}
70
71static int wdt_set_timeout(int t)
72{
73 if (t < 1 || t > SBC7240_MAX_TIMEOUT) {
74 pr_err("timeout value must be 1<=x<=%d\n", SBC7240_MAX_TIMEOUT);
75 return -1;
76 }
77 /* set the timeout */
78 outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT);
79 timeout = t;
80 pr_info("timeout set to %d seconds\n", t);
81 return 0;
82}
83
84/* Whack the dog */
85static 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 */
94static 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
123static 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
130 return stream_open(inode, file);
131}
132
133static 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 {
139 pr_crit("Unexpected close, not stopping watchdog!\n");
140 wdt_keepalive();
141 }
142
143 clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status);
144 return 0;
145}
146
147static const struct watchdog_info ident = {
148 .options = WDIOF_KEEPALIVEPING|
149 WDIOF_SETTIMEOUT|
150 WDIOF_MAGICCLOSE,
151 .firmware_version = 1,
152 .identity = "SBC7240",
153};
154
155
156static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
157{
158 switch (cmd) {
159 case WDIOC_GETSUPPORT:
160 return copy_to_user((void __user *)arg, &ident, sizeof(ident))
161 ? -EFAULT : 0;
162 case WDIOC_GETSTATUS:
163 case WDIOC_GETBOOTSTATUS:
164 return put_user(0, (int __user *)arg);
165 case WDIOC_SETOPTIONS:
166 {
167 int options;
168 int retval = -EINVAL;
169
170 if (get_user(options, (int __user *)arg))
171 return -EFAULT;
172
173 if (options & WDIOS_DISABLECARD) {
174 wdt_disable();
175 retval = 0;
176 }
177
178 if (options & WDIOS_ENABLECARD) {
179 wdt_enable();
180 retval = 0;
181 }
182
183 return retval;
184 }
185 case WDIOC_KEEPALIVE:
186 wdt_keepalive();
187 return 0;
188 case WDIOC_SETTIMEOUT:
189 {
190 int new_timeout;
191
192 if (get_user(new_timeout, (int __user *)arg))
193 return -EFAULT;
194
195 if (wdt_set_timeout(new_timeout))
196 return -EINVAL;
197 }
198 fallthrough;
199 case WDIOC_GETTIMEOUT:
200 return put_user(timeout, (int __user *)arg);
201 default:
202 return -ENOTTY;
203 }
204}
205
206static const struct file_operations wdt_fops = {
207 .owner = THIS_MODULE,
208 .llseek = no_llseek,
209 .write = fop_write,
210 .open = fop_open,
211 .release = fop_close,
212 .unlocked_ioctl = fop_ioctl,
213 .compat_ioctl = compat_ptr_ioctl,
214};
215
216static 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
226static 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
234static struct notifier_block wdt_notifier = {
235 .notifier_call = wdt_notify_sys,
236};
237
238static void __exit sbc7240_wdt_unload(void)
239{
240 pr_info("Removing watchdog\n");
241 misc_deregister(&wdt_miscdev);
242
243 unregister_reboot_notifier(&wdt_notifier);
244 release_region(SBC7240_ENABLE_PORT, 1);
245}
246
247static int __init sbc7240_wdt_init(void)
248{
249 int rc = -EBUSY;
250
251 if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) {
252 pr_err("I/O address 0x%04x already in use\n",
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
260 * can't request_region() it ...*/
261
262 if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) {
263 timeout = SBC7240_TIMEOUT;
264 pr_info("timeout value must be 1<=x<=%d, using %d\n",
265 SBC7240_MAX_TIMEOUT, timeout);
266 }
267 wdt_set_timeout(timeout);
268 wdt_disable();
269
270 rc = register_reboot_notifier(&wdt_notifier);
271 if (rc) {
272 pr_err("cannot register reboot notifier (err=%d)\n", rc);
273 goto err_out_region;
274 }
275
276 rc = misc_register(&wdt_miscdev);
277 if (rc) {
278 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
279 wdt_miscdev.minor, rc);
280 goto err_out_reboot_notifier;
281 }
282
283 pr_info("Watchdog driver for SBC7240 initialised (nowayout=%d)\n",
284 nowayout);
285
286 return 0;
287
288err_out_reboot_notifier:
289 unregister_reboot_notifier(&wdt_notifier);
290err_out_region:
291 release_region(SBC7240_ENABLE_PORT, 1);
292err_out:
293 return rc;
294}
295
296module_init(sbc7240_wdt_init);
297module_exit(sbc7240_wdt_unload);
298
299MODULE_AUTHOR("Gilles Gigan");
300MODULE_DESCRIPTION("Watchdog device driver for single board"
301 " computers EPIC Nano 7240 from iEi");
302MODULE_LICENSE("GPL");