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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
53 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
54
55
56 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
57
58
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
224
225 cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
226 GEODEWDT_SCALE | (3 << 8));
227
228
229 cs5535_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1);
230
231
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 int geodewdt_remove(struct platform_device *dev)
242{
243 misc_deregister(&geodewdt_miscdev);
244 return 0;
245}
246
247static void geodewdt_shutdown(struct platform_device *dev)
248{
249 geodewdt_disable();
250}
251
252static struct platform_driver geodewdt_driver = {
253 .remove = geodewdt_remove,
254 .shutdown = geodewdt_shutdown,
255 .driver = {
256 .name = DRV_NAME,
257 },
258};
259
260static int __init geodewdt_init(void)
261{
262 int ret;
263
264 geodewdt_platform_device = platform_device_register_simple(DRV_NAME,
265 -1, NULL, 0);
266 if (IS_ERR(geodewdt_platform_device))
267 return PTR_ERR(geodewdt_platform_device);
268
269 ret = platform_driver_probe(&geodewdt_driver, geodewdt_probe);
270 if (ret)
271 goto err;
272
273 return 0;
274err:
275 platform_device_unregister(geodewdt_platform_device);
276 return ret;
277}
278
279static void __exit geodewdt_exit(void)
280{
281 platform_device_unregister(geodewdt_platform_device);
282 platform_driver_unregister(&geodewdt_driver);
283}
284
285module_init(geodewdt_init);
286module_exit(geodewdt_exit);
287
288MODULE_AUTHOR("Advanced Micro Devices, Inc");
289MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver");
290MODULE_LICENSE("GPL");
291
