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26#include <linux/module.h>
27#include <linux/moduleparam.h>
28#include <linux/errno.h>
29#include <linux/init.h>
30#include <linux/miscdevice.h>
31#include <linux/watchdog.h>
32#include <linux/notifier.h>
33#include <linux/reboot.h>
34#include <linux/fs.h>
35#include <linux/ioport.h>
36#include <linux/io.h>
37#include <linux/uaccess.h>
38
39#include <asm/addrspace.h>
40#include <asm/ar7/ar7.h>
41
42#define DRVNAME "ar7_wdt"
43#define LONGNAME "TI AR7 Watchdog Timer"
44
45MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>");
46MODULE_DESCRIPTION(LONGNAME);
47MODULE_LICENSE("GPL");
48MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
49
50static int margin = 60;
51module_param(margin, int, 0);
52MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
53
54static int nowayout = WATCHDOG_NOWAYOUT;
55module_param(nowayout, int, 0);
56MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
57
58#define READ_REG(x) readl((void __iomem *)&(x))
59#define WRITE_REG(x, v) writel((v), (void __iomem *)&(x))
60
61struct ar7_wdt {
62 u32 kick_lock;
63 u32 kick;
64 u32 change_lock;
65 u32 change;
66 u32 disable_lock;
67 u32 disable;
68 u32 prescale_lock;
69 u32 prescale;
70};
71
72static unsigned long wdt_is_open;
73static spinlock_t wdt_lock;
74static unsigned expect_close;
75
76
77#define prescale_value 0xffff
78
79
80static unsigned long ar7_regs_wdt;
81
82static struct ar7_wdt *ar7_wdt;
83static void ar7_wdt_get_regs(void)
84{
85 u16 chip_id = ar7_chip_id();
86 switch (chip_id) {
87 case AR7_CHIP_7100:
88 case AR7_CHIP_7200:
89 ar7_regs_wdt = AR7_REGS_WDT;
90 break;
91 default:
92 ar7_regs_wdt = UR8_REGS_WDT;
93 break;
94 }
95}
96
97
98static void ar7_wdt_kick(u32 value)
99{
100 WRITE_REG(ar7_wdt->kick_lock, 0x5555);
101 if ((READ_REG(ar7_wdt->kick_lock) & 3) == 1) {
102 WRITE_REG(ar7_wdt->kick_lock, 0xaaaa);
103 if ((READ_REG(ar7_wdt->kick_lock) & 3) == 3) {
104 WRITE_REG(ar7_wdt->kick, value);
105 return;
106 }
107 }
108 printk(KERN_ERR DRVNAME ": failed to unlock WDT kick reg\n");
109}
110
111static void ar7_wdt_prescale(u32 value)
112{
113 WRITE_REG(ar7_wdt->prescale_lock, 0x5a5a);
114 if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 1) {
115 WRITE_REG(ar7_wdt->prescale_lock, 0xa5a5);
116 if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 3) {
117 WRITE_REG(ar7_wdt->prescale, value);
118 return;
119 }
120 }
121 printk(KERN_ERR DRVNAME ": failed to unlock WDT prescale reg\n");
122}
123
124static void ar7_wdt_change(u32 value)
125{
126 WRITE_REG(ar7_wdt->change_lock, 0x6666);
127 if ((READ_REG(ar7_wdt->change_lock) & 3) == 1) {
128 WRITE_REG(ar7_wdt->change_lock, 0xbbbb);
129 if ((READ_REG(ar7_wdt->change_lock) & 3) == 3) {
130 WRITE_REG(ar7_wdt->change, value);
131 return;
132 }
133 }
134 printk(KERN_ERR DRVNAME ": failed to unlock WDT change reg\n");
135}
136
137static void ar7_wdt_disable(u32 value)
138{
139 WRITE_REG(ar7_wdt->disable_lock, 0x7777);
140 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 1) {
141 WRITE_REG(ar7_wdt->disable_lock, 0xcccc);
142 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 2) {
143 WRITE_REG(ar7_wdt->disable_lock, 0xdddd);
144 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 3) {
145 WRITE_REG(ar7_wdt->disable, value);
146 return;
147 }
148 }
149 }
150 printk(KERN_ERR DRVNAME ": failed to unlock WDT disable reg\n");
151}
152
153static void ar7_wdt_update_margin(int new_margin)
154{
155 u32 change;
156
157 change = new_margin * (ar7_vbus_freq() / prescale_value);
158 if (change < 1)
159 change = 1;
160 if (change > 0xffff)
161 change = 0xffff;
162 ar7_wdt_change(change);
163 margin = change * prescale_value / ar7_vbus_freq();
164 printk(KERN_INFO DRVNAME
165 ": timer margin %d seconds (prescale %d, change %d, freq %d)\n",
166 margin, prescale_value, change, ar7_vbus_freq());
167}
168
169static void ar7_wdt_enable_wdt(void)
170{
171 printk(KERN_DEBUG DRVNAME ": enabling watchdog timer\n");
172 ar7_wdt_disable(1);
173 ar7_wdt_kick(1);
174}
175
176static void ar7_wdt_disable_wdt(void)
177{
178 printk(KERN_DEBUG DRVNAME ": disabling watchdog timer\n");
179 ar7_wdt_disable(0);
180}
181
182static int ar7_wdt_open(struct inode *inode, struct file *file)
183{
184
185 if (test_and_set_bit(0, &wdt_is_open))
186 return -EBUSY;
187 ar7_wdt_enable_wdt();
188 expect_close = 0;
189
190 return nonseekable_open(inode, file);
191}
192
193static int ar7_wdt_release(struct inode *inode, struct file *file)
194{
195 if (!expect_close)
196 printk(KERN_WARNING DRVNAME
197 ": watchdog device closed unexpectedly,"
198 "will not disable the watchdog timer\n");
199 else if (!nowayout)
200 ar7_wdt_disable_wdt();
201 clear_bit(0, &wdt_is_open);
202 return 0;
203}
204
205static int ar7_wdt_notify_sys(struct notifier_block *this,
206 unsigned long code, void *unused)
207{
208 if (code == SYS_HALT || code == SYS_POWER_OFF)
209 if (!nowayout)
210 ar7_wdt_disable_wdt();
211
212 return NOTIFY_DONE;
213}
214
215static struct notifier_block ar7_wdt_notifier = {
216 .notifier_call = ar7_wdt_notify_sys,
217};
218
219static ssize_t ar7_wdt_write(struct file *file, const char *data,
220 size_t len, loff_t *ppos)
221{
222
223 if (len) {
224 size_t i;
225
226 spin_lock(&wdt_lock);
227 ar7_wdt_kick(1);
228 spin_unlock(&wdt_lock);
229
230 expect_close = 0;
231 for (i = 0; i < len; ++i) {
232 char c;
233 if (get_user(c, data + i))
234 return -EFAULT;
235 if (c == 'V')
236 expect_close = 1;
237 }
238
239 }
240 return len;
241}
242
243static long ar7_wdt_ioctl(struct file *file,
244 unsigned int cmd, unsigned long arg)
245{
246 static struct watchdog_info ident = {
247 .identity = LONGNAME,
248 .firmware_version = 1,
249 .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING),
250 };
251 int new_margin;
252
253 switch (cmd) {
254 case WDIOC_GETSUPPORT:
255 if (copy_to_user((struct watchdog_info *)arg, &ident,
256 sizeof(ident)))
257 return -EFAULT;
258 return 0;
259 case WDIOC_GETSTATUS:
260 case WDIOC_GETBOOTSTATUS:
261 if (put_user(0, (int *)arg))
262 return -EFAULT;
263 return 0;
264 case WDIOC_KEEPALIVE:
265 ar7_wdt_kick(1);
266 return 0;
267 case WDIOC_SETTIMEOUT:
268 if (get_user(new_margin, (int *)arg))
269 return -EFAULT;
270 if (new_margin < 1)
271 return -EINVAL;
272
273 spin_lock(&wdt_lock);
274 ar7_wdt_update_margin(new_margin);
275 ar7_wdt_kick(1);
276 spin_unlock(&wdt_lock);
277
278 case WDIOC_GETTIMEOUT:
279 if (put_user(margin, (int *)arg))
280 return -EFAULT;
281 return 0;
282 default:
283 return -ENOTTY;
284 }
285}
286
287static const struct file_operations ar7_wdt_fops = {
288 .owner = THIS_MODULE,
289 .write = ar7_wdt_write,
290 .unlocked_ioctl = ar7_wdt_ioctl,
291 .open = ar7_wdt_open,
292 .release = ar7_wdt_release,
293};
294
295static struct miscdevice ar7_wdt_miscdev = {
296 .minor = WATCHDOG_MINOR,
297 .name = "watchdog",
298 .fops = &ar7_wdt_fops,
299};
300
301static int __init ar7_wdt_init(void)
302{
303 int rc;
304
305 spin_lock_init(&wdt_lock);
306
307 ar7_wdt_get_regs();
308
309 if (!request_mem_region(ar7_regs_wdt, sizeof(struct ar7_wdt),
310 LONGNAME)) {
311 printk(KERN_WARNING DRVNAME ": watchdog I/O region busy\n");
312 return -EBUSY;
313 }
314
315 ar7_wdt = (struct ar7_wdt *)
316 ioremap(ar7_regs_wdt, sizeof(struct ar7_wdt));
317
318 ar7_wdt_disable_wdt();
319 ar7_wdt_prescale(prescale_value);
320 ar7_wdt_update_margin(margin);
321
322 rc = register_reboot_notifier(&ar7_wdt_notifier);
323 if (rc) {
324 printk(KERN_ERR DRVNAME
325 ": unable to register reboot notifier\n");
326 goto out_alloc;
327 }
328
329 rc = misc_register(&ar7_wdt_miscdev);
330 if (rc) {
331 printk(KERN_ERR DRVNAME ": unable to register misc device\n");
332 goto out_register;
333 }
334 goto out;
335
336out_register:
337 unregister_reboot_notifier(&ar7_wdt_notifier);
338out_alloc:
339 iounmap(ar7_wdt);
340 release_mem_region(ar7_regs_wdt, sizeof(struct ar7_wdt));
341out:
342 return rc;
343}
344
345static void __exit ar7_wdt_cleanup(void)
346{
347 misc_deregister(&ar7_wdt_miscdev);
348 unregister_reboot_notifier(&ar7_wdt_notifier);
349 iounmap(ar7_wdt);
350 release_mem_region(ar7_regs_wdt, sizeof(struct ar7_wdt));
351}
352
353module_init(ar7_wdt_init);
354module_exit(ar7_wdt_cleanup);
355
