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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Watchdog timer for machines with the CS5535/CS5536 companion chip
3 *
4 * Copyright (C) 2006-2007, Advanced Micro Devices, Inc.
5 * Copyright (C) 2009 Andres Salomon <dilinger@collabora.co.uk>
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/module.h>
11#include <linux/moduleparam.h>
12#include <linux/types.h>
13#include <linux/miscdevice.h>
14#include <linux/watchdog.h>
15#include <linux/fs.h>
16#include <linux/platform_device.h>
17#include <linux/reboot.h>
18#include <linux/uaccess.h>
19
20#include <linux/cs5535.h>
21
22#define GEODEWDT_HZ 500
23#define GEODEWDT_SCALE 6
24#define GEODEWDT_MAX_SECONDS 131
25
26#define WDT_FLAGS_OPEN 1
27#define WDT_FLAGS_ORPHAN 2
28
29#define DRV_NAME "geodewdt"
30#define WATCHDOG_NAME "Geode GX/LX WDT"
31#define WATCHDOG_TIMEOUT 60
32
33static int timeout = WATCHDOG_TIMEOUT;
34module_param(timeout, int, 0);
35MODULE_PARM_DESC(timeout,
36 "Watchdog timeout in seconds. 1<= timeout <=131, default="
37 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
38
39static bool nowayout = WATCHDOG_NOWAYOUT;
40module_param(nowayout, bool, 0);
41MODULE_PARM_DESC(nowayout,
42 "Watchdog cannot be stopped once started (default="
43 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
44
45static struct platform_device *geodewdt_platform_device;
46static unsigned long wdt_flags;
47static struct cs5535_mfgpt_timer *wdt_timer;
48static int safe_close;
49
50static void geodewdt_ping(void)
51{
52 /* Stop the counter */
53 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
54
55 /* Reset the counter */
56 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
57
58 /* Enable the counter */
59 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
60}
61
62static void geodewdt_disable(void)
63{
64 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
65 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
66}
67
68static int geodewdt_set_heartbeat(int val)
69{
70 if (val < 1 || val > GEODEWDT_MAX_SECONDS)
71 return -EINVAL;
72
73 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
74 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ);
75 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
76 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
77
78 timeout = val;
79 return 0;
80}
81
82static int geodewdt_open(struct inode *inode, struct file *file)
83{
84 if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags))
85 return -EBUSY;
86
87 if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags))
88 __module_get(THIS_MODULE);
89
90 geodewdt_ping();
91 return stream_open(inode, file);
92}
93
94static int geodewdt_release(struct inode *inode, struct file *file)
95{
96 if (safe_close) {
97 geodewdt_disable();
98 module_put(THIS_MODULE);
99 } else {
100 pr_crit("Unexpected close - watchdog is not stopping\n");
101 geodewdt_ping();
102
103 set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
104 }
105
106 clear_bit(WDT_FLAGS_OPEN, &wdt_flags);
107 safe_close = 0;
108 return 0;
109}
110
111static ssize_t geodewdt_write(struct file *file, const char __user *data,
112 size_t len, loff_t *ppos)
113{
114 if (len) {
115 if (!nowayout) {
116 size_t i;
117 safe_close = 0;
118
119 for (i = 0; i != len; i++) {
120 char c;
121
122 if (get_user(c, data + i))
123 return -EFAULT;
124
125 if (c == 'V')
126 safe_close = 1;
127 }
128 }
129
130 geodewdt_ping();
131 }
132 return len;
133}
134
135static long geodewdt_ioctl(struct file *file, unsigned int cmd,
136 unsigned long arg)
137{
138 void __user *argp = (void __user *)arg;
139 int __user *p = argp;
140 int interval;
141
142 static const struct watchdog_info ident = {
143 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
144 | WDIOF_MAGICCLOSE,
145 .firmware_version = 1,
146 .identity = WATCHDOG_NAME,
147 };
148
149 switch (cmd) {
150 case WDIOC_GETSUPPORT:
151 return copy_to_user(argp, &ident,
152 sizeof(ident)) ? -EFAULT : 0;
153 case WDIOC_GETSTATUS:
154 case WDIOC_GETBOOTSTATUS:
155 return put_user(0, p);
156
157 case WDIOC_SETOPTIONS:
158 {
159 int options, ret = -EINVAL;
160
161 if (get_user(options, p))
162 return -EFAULT;
163
164 if (options & WDIOS_DISABLECARD) {
165 geodewdt_disable();
166 ret = 0;
167 }
168
169 if (options & WDIOS_ENABLECARD) {
170 geodewdt_ping();
171 ret = 0;
172 }
173
174 return ret;
175 }
176 case WDIOC_KEEPALIVE:
177 geodewdt_ping();
178 return 0;
179
180 case WDIOC_SETTIMEOUT:
181 if (get_user(interval, p))
182 return -EFAULT;
183
184 if (geodewdt_set_heartbeat(interval))
185 return -EINVAL;
186 fallthrough;
187 case WDIOC_GETTIMEOUT:
188 return put_user(timeout, p);
189
190 default:
191 return -ENOTTY;
192 }
193
194 return 0;
195}
196
197static const struct file_operations geodewdt_fops = {
198 .owner = THIS_MODULE,
199 .llseek = no_llseek,
200 .write = geodewdt_write,
201 .unlocked_ioctl = geodewdt_ioctl,
202 .compat_ioctl = compat_ptr_ioctl,
203 .open = geodewdt_open,
204 .release = geodewdt_release,
205};
206
207static struct miscdevice geodewdt_miscdev = {
208 .minor = WATCHDOG_MINOR,
209 .name = "watchdog",
210 .fops = &geodewdt_fops,
211};
212
213static int __init geodewdt_probe(struct platform_device *dev)
214{
215 int ret;
216
217 wdt_timer = cs5535_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING);
218 if (!wdt_timer) {
219 pr_err("No timers were available\n");
220 return -ENODEV;
221 }
222
223 /* Set up the timer */
224
225 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
226 GEODEWDT_SCALE | (3 << 8));
227
228 /* Set up comparator 2 to reset when the event fires */
229 cs5535_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1);
230
231 /* Set up the initial timeout */
232
233 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2,
234 timeout * GEODEWDT_HZ);
235
236 ret = misc_register(&geodewdt_miscdev);
237
238 return ret;
239}
240
241static void geodewdt_remove(struct platform_device *dev)
242{
243 misc_deregister(&geodewdt_miscdev);
244}
245
246static void geodewdt_shutdown(struct platform_device *dev)
247{
248 geodewdt_disable();
249}
250
251static struct platform_driver geodewdt_driver = {
252 .remove_new = geodewdt_remove,
253 .shutdown = geodewdt_shutdown,
254 .driver = {
255 .name = DRV_NAME,
256 },
257};
258
259static int __init geodewdt_init(void)
260{
261 int ret;
262
263 geodewdt_platform_device = platform_device_register_simple(DRV_NAME,
264 -1, NULL, 0);
265 if (IS_ERR(geodewdt_platform_device))
266 return PTR_ERR(geodewdt_platform_device);
267
268 ret = platform_driver_probe(&geodewdt_driver, geodewdt_probe);
269 if (ret)
270 goto err;
271
272 return 0;
273err:
274 platform_device_unregister(geodewdt_platform_device);
275 return ret;
276}
277
278static void __exit geodewdt_exit(void)
279{
280 platform_device_unregister(geodewdt_platform_device);
281 platform_driver_unregister(&geodewdt_driver);
282}
283
284module_init(geodewdt_init);
285module_exit(geodewdt_exit);
286
287MODULE_AUTHOR("Advanced Micro Devices, Inc");
288MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver");
289MODULE_LICENSE("GPL");
1/* Watchdog timer for machines with the CS5535/CS5536 companion chip
2 *
3 * Copyright (C) 2006-2007, Advanced Micro Devices, Inc.
4 * Copyright (C) 2009 Andres Salomon <dilinger@collabora.co.uk>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/module.h>
15#include <linux/moduleparam.h>
16#include <linux/types.h>
17#include <linux/miscdevice.h>
18#include <linux/watchdog.h>
19#include <linux/fs.h>
20#include <linux/platform_device.h>
21#include <linux/reboot.h>
22#include <linux/uaccess.h>
23
24#include <linux/cs5535.h>
25
26#define GEODEWDT_HZ 500
27#define GEODEWDT_SCALE 6
28#define GEODEWDT_MAX_SECONDS 131
29
30#define WDT_FLAGS_OPEN 1
31#define WDT_FLAGS_ORPHAN 2
32
33#define DRV_NAME "geodewdt"
34#define WATCHDOG_NAME "Geode GX/LX WDT"
35#define WATCHDOG_TIMEOUT 60
36
37static int timeout = WATCHDOG_TIMEOUT;
38module_param(timeout, int, 0);
39MODULE_PARM_DESC(timeout,
40 "Watchdog timeout in seconds. 1<= timeout <=131, default="
41 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
42
43static bool nowayout = WATCHDOG_NOWAYOUT;
44module_param(nowayout, bool, 0);
45MODULE_PARM_DESC(nowayout,
46 "Watchdog cannot be stopped once started (default="
47 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
48
49static struct platform_device *geodewdt_platform_device;
50static unsigned long wdt_flags;
51static struct cs5535_mfgpt_timer *wdt_timer;
52static int safe_close;
53
54static void geodewdt_ping(void)
55{
56 /* Stop the counter */
57 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
58
59 /* Reset the counter */
60 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
61
62 /* Enable the counter */
63 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
64}
65
66static void geodewdt_disable(void)
67{
68 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
69 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
70}
71
72static int geodewdt_set_heartbeat(int val)
73{
74 if (val < 1 || val > GEODEWDT_MAX_SECONDS)
75 return -EINVAL;
76
77 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
78 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ);
79 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
80 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
81
82 timeout = val;
83 return 0;
84}
85
86static int geodewdt_open(struct inode *inode, struct file *file)
87{
88 if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags))
89 return -EBUSY;
90
91 if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags))
92 __module_get(THIS_MODULE);
93
94 geodewdt_ping();
95 return nonseekable_open(inode, file);
96}
97
98static int geodewdt_release(struct inode *inode, struct file *file)
99{
100 if (safe_close) {
101 geodewdt_disable();
102 module_put(THIS_MODULE);
103 } else {
104 pr_crit("Unexpected close - watchdog is not stopping\n");
105 geodewdt_ping();
106
107 set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
108 }
109
110 clear_bit(WDT_FLAGS_OPEN, &wdt_flags);
111 safe_close = 0;
112 return 0;
113}
114
115static ssize_t geodewdt_write(struct file *file, const char __user *data,
116 size_t len, loff_t *ppos)
117{
118 if (len) {
119 if (!nowayout) {
120 size_t i;
121 safe_close = 0;
122
123 for (i = 0; i != len; i++) {
124 char c;
125
126 if (get_user(c, data + i))
127 return -EFAULT;
128
129 if (c == 'V')
130 safe_close = 1;
131 }
132 }
133
134 geodewdt_ping();
135 }
136 return len;
137}
138
139static long geodewdt_ioctl(struct file *file, unsigned int cmd,
140 unsigned long arg)
141{
142 void __user *argp = (void __user *)arg;
143 int __user *p = argp;
144 int interval;
145
146 static const struct watchdog_info ident = {
147 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
148 | WDIOF_MAGICCLOSE,
149 .firmware_version = 1,
150 .identity = WATCHDOG_NAME,
151 };
152
153 switch (cmd) {
154 case WDIOC_GETSUPPORT:
155 return copy_to_user(argp, &ident,
156 sizeof(ident)) ? -EFAULT : 0;
157 break;
158
159 case WDIOC_GETSTATUS:
160 case WDIOC_GETBOOTSTATUS:
161 return put_user(0, p);
162
163 case WDIOC_SETOPTIONS:
164 {
165 int options, ret = -EINVAL;
166
167 if (get_user(options, p))
168 return -EFAULT;
169
170 if (options & WDIOS_DISABLECARD) {
171 geodewdt_disable();
172 ret = 0;
173 }
174
175 if (options & WDIOS_ENABLECARD) {
176 geodewdt_ping();
177 ret = 0;
178 }
179
180 return ret;
181 }
182 case WDIOC_KEEPALIVE:
183 geodewdt_ping();
184 return 0;
185
186 case WDIOC_SETTIMEOUT:
187 if (get_user(interval, p))
188 return -EFAULT;
189
190 if (geodewdt_set_heartbeat(interval))
191 return -EINVAL;
192 /* Fall through */
193 case WDIOC_GETTIMEOUT:
194 return put_user(timeout, p);
195
196 default:
197 return -ENOTTY;
198 }
199
200 return 0;
201}
202
203static const struct file_operations geodewdt_fops = {
204 .owner = THIS_MODULE,
205 .llseek = no_llseek,
206 .write = geodewdt_write,
207 .unlocked_ioctl = geodewdt_ioctl,
208 .open = geodewdt_open,
209 .release = geodewdt_release,
210};
211
212static struct miscdevice geodewdt_miscdev = {
213 .minor = WATCHDOG_MINOR,
214 .name = "watchdog",
215 .fops = &geodewdt_fops,
216};
217
218static int __devinit geodewdt_probe(struct platform_device *dev)
219{
220 int ret;
221
222 wdt_timer = cs5535_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING);
223 if (!wdt_timer) {
224 pr_err("No timers were available\n");
225 return -ENODEV;
226 }
227
228 /* Set up the timer */
229
230 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
231 GEODEWDT_SCALE | (3 << 8));
232
233 /* Set up comparator 2 to reset when the event fires */
234 cs5535_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1);
235
236 /* Set up the initial timeout */
237
238 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2,
239 timeout * GEODEWDT_HZ);
240
241 ret = misc_register(&geodewdt_miscdev);
242
243 return ret;
244}
245
246static int __devexit geodewdt_remove(struct platform_device *dev)
247{
248 misc_deregister(&geodewdt_miscdev);
249 return 0;
250}
251
252static void geodewdt_shutdown(struct platform_device *dev)
253{
254 geodewdt_disable();
255}
256
257static struct platform_driver geodewdt_driver = {
258 .probe = geodewdt_probe,
259 .remove = __devexit_p(geodewdt_remove),
260 .shutdown = geodewdt_shutdown,
261 .driver = {
262 .owner = THIS_MODULE,
263 .name = DRV_NAME,
264 },
265};
266
267static int __init geodewdt_init(void)
268{
269 int ret;
270
271 ret = platform_driver_register(&geodewdt_driver);
272 if (ret)
273 return ret;
274
275 geodewdt_platform_device = platform_device_register_simple(DRV_NAME,
276 -1, NULL, 0);
277 if (IS_ERR(geodewdt_platform_device)) {
278 ret = PTR_ERR(geodewdt_platform_device);
279 goto err;
280 }
281
282 return 0;
283err:
284 platform_driver_unregister(&geodewdt_driver);
285 return ret;
286}
287
288static void __exit geodewdt_exit(void)
289{
290 platform_device_unregister(geodewdt_platform_device);
291 platform_driver_unregister(&geodewdt_driver);
292}
293
294module_init(geodewdt_init);
295module_exit(geodewdt_exit);
296
297MODULE_AUTHOR("Advanced Micro Devices, Inc");
298MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver");
299MODULE_LICENSE("GPL");
300MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);