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24#include <linux/init.h>
25#include <linux/kernel.h>
26#include <linux/module.h>
27#include <linux/moduleparam.h>
28#include <linux/miscdevice.h>
29#include <linux/fs.h>
30#include <linux/platform_device.h>
31#include <linux/watchdog.h>
32#include <linux/uaccess.h>
33#include <linux/io.h>
34#include <linux/spinlock.h>
35#include <linux/slab.h>
36
37#define TIMEOUT_MIN 1
38#define TIMEOUT_MAX 2
39#define TIMEOUT_DEFAULT TIMEOUT_MAX
40
41
42static int timeout = TIMEOUT_DEFAULT;
43module_param(timeout, int, 0);
44MODULE_PARM_DESC(timeout,
45 "Timeout value. Limited to be 1 or 2 seconds. (default="
46 __MODULE_STRING(TIMEOUT_DEFAULT) ")");
47
48static int nowayout = WATCHDOG_NOWAYOUT;
49module_param(nowayout, int, 0);
50MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
51 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
52
53
54#define WDT_CTRL 0x00
55#define WDT_CTRL_EN 0
56#define WDT_CTRL_PSEL 8
57#define WDT_CTRL_KEY 24
58
59#define WDT_CLR 0x04
60
61#define WDT_RCAUSE 0x10
62#define WDT_RCAUSE_POR 0
63#define WDT_RCAUSE_EXT 2
64#define WDT_RCAUSE_WDT 3
65#define WDT_RCAUSE_JTAG 4
66#define WDT_RCAUSE_SERP 5
67
68#define WDT_BIT(name) (1 << WDT_##name)
69#define WDT_BF(name, value) ((value) << WDT_##name)
70
71#define wdt_readl(dev, reg) \
72 __raw_readl((dev)->regs + WDT_##reg)
73#define wdt_writel(dev, reg, value) \
74 __raw_writel((value), (dev)->regs + WDT_##reg)
75
76struct wdt_at32ap700x {
77 void __iomem *regs;
78 spinlock_t io_lock;
79 int timeout;
80 int boot_status;
81 unsigned long users;
82 struct miscdevice miscdev;
83};
84
85static struct wdt_at32ap700x *wdt;
86static char expect_release;
87
88
89
90
91static inline void at32_wdt_stop(void)
92{
93 unsigned long psel;
94
95 spin_lock(&wdt->io_lock);
96 psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f);
97 wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55));
98 wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa));
99 spin_unlock(&wdt->io_lock);
100}
101
102
103
104
105static inline void at32_wdt_start(void)
106{
107
108 unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe;
109
110 spin_lock(&wdt->io_lock);
111 wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
112 | WDT_BF(CTRL_PSEL, psel)
113 | WDT_BF(CTRL_KEY, 0x55));
114 wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
115 | WDT_BF(CTRL_PSEL, psel)
116 | WDT_BF(CTRL_KEY, 0xaa));
117 spin_unlock(&wdt->io_lock);
118}
119
120
121
122
123static inline void at32_wdt_pat(void)
124{
125 spin_lock(&wdt->io_lock);
126 wdt_writel(wdt, CLR, 0x42);
127 spin_unlock(&wdt->io_lock);
128}
129
130
131
132
133static int at32_wdt_open(struct inode *inode, struct file *file)
134{
135 if (test_and_set_bit(1, &wdt->users))
136 return -EBUSY;
137
138 at32_wdt_start();
139 return nonseekable_open(inode, file);
140}
141
142
143
144
145static int at32_wdt_close(struct inode *inode, struct file *file)
146{
147 if (expect_release == 42) {
148 at32_wdt_stop();
149 } else {
150 dev_dbg(wdt->miscdev.parent,
151 "unexpected close, not stopping watchdog!\n");
152 at32_wdt_pat();
153 }
154 clear_bit(1, &wdt->users);
155 expect_release = 0;
156 return 0;
157}
158
159
160
161
162static int at32_wdt_settimeout(int time)
163{
164
165
166
167
168 if ((time < TIMEOUT_MIN) || (time > TIMEOUT_MAX))
169 return -EINVAL;
170
171
172
173
174
175 wdt->timeout = time;
176 return 0;
177}
178
179
180
181
182static int at32_wdt_get_status(void)
183{
184 int rcause;
185 int status = 0;
186
187 rcause = wdt_readl(wdt, RCAUSE);
188
189 switch (rcause) {
190 case WDT_BIT(RCAUSE_EXT):
191 status = WDIOF_EXTERN1;
192 break;
193 case WDT_BIT(RCAUSE_WDT):
194 status = WDIOF_CARDRESET;
195 break;
196 case WDT_BIT(RCAUSE_POR):
197 case WDT_BIT(RCAUSE_JTAG):
198 case WDT_BIT(RCAUSE_SERP):
199 default:
200 break;
201 }
202
203 return status;
204}
205
206static const struct watchdog_info at32_wdt_info = {
207 .identity = "at32ap700x watchdog",
208 .options = WDIOF_SETTIMEOUT |
209 WDIOF_KEEPALIVEPING |
210 WDIOF_MAGICCLOSE,
211};
212
213
214
215
216static long at32_wdt_ioctl(struct file *file,
217 unsigned int cmd, unsigned long arg)
218{
219 int ret = -ENOTTY;
220 int time;
221 void __user *argp = (void __user *)arg;
222 int __user *p = argp;
223
224 switch (cmd) {
225 case WDIOC_GETSUPPORT:
226 ret = copy_to_user(argp, &at32_wdt_info,
227 sizeof(at32_wdt_info)) ? -EFAULT : 0;
228 break;
229 case WDIOC_GETSTATUS:
230 ret = put_user(0, p);
231 break;
232 case WDIOC_GETBOOTSTATUS:
233 ret = put_user(wdt->boot_status, p);
234 break;
235 case WDIOC_SETOPTIONS:
236 ret = get_user(time, p);
237 if (ret)
238 break;
239 if (time & WDIOS_DISABLECARD)
240 at32_wdt_stop();
241 if (time & WDIOS_ENABLECARD)
242 at32_wdt_start();
243 ret = 0;
244 break;
245 case WDIOC_KEEPALIVE:
246 at32_wdt_pat();
247 ret = 0;
248 break;
249 case WDIOC_SETTIMEOUT:
250 ret = get_user(time, p);
251 if (ret)
252 break;
253 ret = at32_wdt_settimeout(time);
254 if (ret)
255 break;
256
257 at32_wdt_start();
258
259 case WDIOC_GETTIMEOUT:
260 ret = put_user(wdt->timeout, p);
261 break;
262 }
263
264 return ret;
265}
266
267static ssize_t at32_wdt_write(struct file *file, const char __user *data,
268 size_t len, loff_t *ppos)
269{
270
271 if (len) {
272 if (!nowayout) {
273 size_t i;
274
275
276
277
278
279 expect_release = 0;
280
281
282
283
284
285 for (i = 0; i != len; i++) {
286 char c;
287 if (get_user(c, data + i))
288 return -EFAULT;
289 if (c == 'V')
290 expect_release = 42;
291 }
292 }
293
294 at32_wdt_pat();
295 }
296 return len;
297}
298
299static const struct file_operations at32_wdt_fops = {
300 .owner = THIS_MODULE,
301 .llseek = no_llseek,
302 .unlocked_ioctl = at32_wdt_ioctl,
303 .open = at32_wdt_open,
304 .release = at32_wdt_close,
305 .write = at32_wdt_write,
306};
307
308static int __init at32_wdt_probe(struct platform_device *pdev)
309{
310 struct resource *regs;
311 int ret;
312
313 if (wdt) {
314 dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n");
315 return -EBUSY;
316 }
317
318 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
319 if (!regs) {
320 dev_dbg(&pdev->dev, "missing mmio resource\n");
321 return -ENXIO;
322 }
323
324 wdt = kzalloc(sizeof(struct wdt_at32ap700x), GFP_KERNEL);
325 if (!wdt) {
326 dev_dbg(&pdev->dev, "no memory for wdt structure\n");
327 return -ENOMEM;
328 }
329
330 wdt->regs = ioremap(regs->start, resource_size(regs));
331 if (!wdt->regs) {
332 ret = -ENOMEM;
333 dev_dbg(&pdev->dev, "could not map I/O memory\n");
334 goto err_free;
335 }
336
337 spin_lock_init(&wdt->io_lock);
338 wdt->boot_status = at32_wdt_get_status();
339
340
341 if (wdt->boot_status & WDIOF_CARDRESET) {
342 dev_info(&pdev->dev, "CPU must be reset with external "
343 "reset or POR due to silicon errata.\n");
344 ret = -EIO;
345 goto err_iounmap;
346 } else {
347 wdt->users = 0;
348 }
349
350 wdt->miscdev.minor = WATCHDOG_MINOR;
351 wdt->miscdev.name = "watchdog";
352 wdt->miscdev.fops = &at32_wdt_fops;
353 wdt->miscdev.parent = &pdev->dev;
354
355 platform_set_drvdata(pdev, wdt);
356
357 if (at32_wdt_settimeout(timeout)) {
358 at32_wdt_settimeout(TIMEOUT_DEFAULT);
359 dev_dbg(&pdev->dev,
360 "default timeout invalid, set to %d sec.\n",
361 TIMEOUT_DEFAULT);
362 }
363
364 ret = misc_register(&wdt->miscdev);
365 if (ret) {
366 dev_dbg(&pdev->dev, "failed to register wdt miscdev\n");
367 goto err_register;
368 }
369
370 dev_info(&pdev->dev,
371 "AT32AP700X WDT at 0x%p, timeout %d sec (nowayout=%d)\n",
372 wdt->regs, wdt->timeout, nowayout);
373
374 return 0;
375
376err_register:
377 platform_set_drvdata(pdev, NULL);
378err_iounmap:
379 iounmap(wdt->regs);
380err_free:
381 kfree(wdt);
382 wdt = NULL;
383 return ret;
384}
385
386static int __exit at32_wdt_remove(struct platform_device *pdev)
387{
388 if (wdt && platform_get_drvdata(pdev) == wdt) {
389
390 if (!nowayout)
391 at32_wdt_stop();
392
393 misc_deregister(&wdt->miscdev);
394 iounmap(wdt->regs);
395 kfree(wdt);
396 wdt = NULL;
397 platform_set_drvdata(pdev, NULL);
398 }
399 return 0;
400}
401
402static void at32_wdt_shutdown(struct platform_device *pdev)
403{
404 at32_wdt_stop();
405}
406
407#ifdef CONFIG_PM
408static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message)
409{
410 at32_wdt_stop();
411 return 0;
412}
413
414static int at32_wdt_resume(struct platform_device *pdev)
415{
416 if (wdt->users)
417 at32_wdt_start();
418 return 0;
419}
420#else
421#define at32_wdt_suspend NULL
422#define at32_wdt_resume NULL
423#endif
424
425
426MODULE_ALIAS("platform:at32_wdt");
427
428static struct platform_driver at32_wdt_driver = {
429 .remove = __exit_p(at32_wdt_remove),
430 .suspend = at32_wdt_suspend,
431 .resume = at32_wdt_resume,
432 .driver = {
433 .name = "at32_wdt",
434 .owner = THIS_MODULE,
435 },
436 .shutdown = at32_wdt_shutdown,
437};
438
439static int __init at32_wdt_init(void)
440{
441 return platform_driver_probe(&at32_wdt_driver, at32_wdt_probe);
442}
443module_init(at32_wdt_init);
444
445static void __exit at32_wdt_exit(void)
446{
447 platform_driver_unregister(&at32_wdt_driver);
448}
449module_exit(at32_wdt_exit);
450
451MODULE_AUTHOR("Hans-Christian Egtvedt <egtvedt@samfundet.no>");
452MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X");
453MODULE_LICENSE("GPL");
454MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
455
