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