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a9cb3959 HCE |
1 | /* |
2 | * Watchdog driver for Atmel AT32AP700X devices | |
3 | * | |
4 | * Copyright (C) 2005-2006 Atmel Corporation | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
bb133450 HCE |
9 | * |
10 | * | |
11 | * Errata: WDT Clear is blocked after WDT Reset | |
12 | * | |
13 | * A watchdog timer event will, after reset, block writes to the WDT_CLEAR | |
14 | * register, preventing the program to clear the next Watchdog Timer Reset. | |
15 | * | |
16 | * If you still want to use the WDT after a WDT reset a small code can be | |
17 | * insterted at the startup checking the AVR32_PM.rcause register for WDT reset | |
18 | * and use a GPIO pin to reset the system. This method requires that one of the | |
19 | * GPIO pins are available and connected externally to the RESET_N pin. After | |
20 | * the GPIO pin has pulled down the reset line the GPIO will be reset and leave | |
21 | * the pin tristated with pullup. | |
a9cb3959 HCE |
22 | */ |
23 | ||
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> | |
c37f2713 AM |
32 | #include <linux/uaccess.h> |
33 | #include <linux/io.h> | |
e75e6577 | 34 | #include <linux/spinlock.h> |
a9cb3959 HCE |
35 | |
36 | #define TIMEOUT_MIN 1 | |
a9cb3959 | 37 | #define TIMEOUT_MAX 2 |
726c9f61 WVS |
38 | #define TIMEOUT_DEFAULT TIMEOUT_MAX |
39 | ||
40 | /* module parameters */ | |
41 | static int timeout = TIMEOUT_DEFAULT; | |
42 | module_param(timeout, int, 0); | |
43 | MODULE_PARM_DESC(timeout, | |
44 | "Timeout value. Limited to be 1 or 2 seconds. (default=" | |
45 | __MODULE_STRING(TIMEOUT_DEFAULT) ")"); | |
a9cb3959 | 46 | |
28401140 WVS |
47 | static int nowayout = WATCHDOG_NOWAYOUT; |
48 | module_param(nowayout, int, 0); | |
49 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" | |
50 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
51 | ||
a9cb3959 HCE |
52 | /* Watchdog registers and write/read macro */ |
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 | ||
bb133450 HCE |
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 | ||
a9cb3959 | 67 | #define WDT_BIT(name) (1 << WDT_##name) |
c0ead7e0 | 68 | #define WDT_BF(name, value) ((value) << WDT_##name) |
a9cb3959 | 69 | |
c0ead7e0 | 70 | #define wdt_readl(dev, reg) \ |
a9cb3959 | 71 | __raw_readl((dev)->regs + WDT_##reg) |
c0ead7e0 | 72 | #define wdt_writel(dev, reg, value) \ |
a9cb3959 HCE |
73 | __raw_writel((value), (dev)->regs + WDT_##reg) |
74 | ||
75 | struct wdt_at32ap700x { | |
76 | void __iomem *regs; | |
e75e6577 | 77 | spinlock_t io_lock; |
a9cb3959 | 78 | int timeout; |
bb133450 | 79 | int boot_status; |
7e2a1498 | 80 | unsigned long users; |
a9cb3959 HCE |
81 | struct miscdevice miscdev; |
82 | }; | |
83 | ||
84 | static struct wdt_at32ap700x *wdt; | |
28401140 | 85 | static char expect_release; |
a9cb3959 HCE |
86 | |
87 | /* | |
88 | * Disable the watchdog. | |
89 | */ | |
c0ead7e0 | 90 | static inline void at32_wdt_stop(void) |
a9cb3959 | 91 | { |
7e2a1498 WVS |
92 | unsigned long psel; |
93 | ||
e75e6577 | 94 | spin_lock(&wdt->io_lock); |
7e2a1498 | 95 | psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f); |
a9cb3959 HCE |
96 | wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55)); |
97 | wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa)); | |
e75e6577 | 98 | spin_unlock(&wdt->io_lock); |
a9cb3959 HCE |
99 | } |
100 | ||
101 | /* | |
102 | * Enable and reset the watchdog. | |
103 | */ | |
c0ead7e0 | 104 | static inline void at32_wdt_start(void) |
a9cb3959 HCE |
105 | { |
106 | /* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */ | |
107 | unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe; | |
108 | ||
e75e6577 | 109 | spin_lock(&wdt->io_lock); |
a9cb3959 HCE |
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)); | |
e75e6577 | 116 | spin_unlock(&wdt->io_lock); |
a9cb3959 HCE |
117 | } |
118 | ||
119 | /* | |
120 | * Pat the watchdog timer. | |
121 | */ | |
c0ead7e0 | 122 | static inline void at32_wdt_pat(void) |
a9cb3959 | 123 | { |
e75e6577 | 124 | spin_lock(&wdt->io_lock); |
a9cb3959 | 125 | wdt_writel(wdt, CLR, 0x42); |
e75e6577 | 126 | spin_unlock(&wdt->io_lock); |
a9cb3959 HCE |
127 | } |
128 | ||
129 | /* | |
130 | * Watchdog device is opened, and watchdog starts running. | |
131 | */ | |
132 | static 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 | /* | |
28401140 | 142 | * Close the watchdog device. |
a9cb3959 HCE |
143 | */ |
144 | static int at32_wdt_close(struct inode *inode, struct file *file) | |
145 | { | |
28401140 WVS |
146 | if (expect_release == 42) { |
147 | at32_wdt_stop(); | |
148 | } else { | |
149 | dev_dbg(wdt->miscdev.parent, | |
bb133450 | 150 | "unexpected close, not stopping watchdog!\n"); |
28401140 WVS |
151 | at32_wdt_pat(); |
152 | } | |
a9cb3959 | 153 | clear_bit(1, &wdt->users); |
28401140 | 154 | expect_release = 0; |
a9cb3959 HCE |
155 | return 0; |
156 | } | |
157 | ||
158 | /* | |
159 | * Change the watchdog time interval. | |
160 | */ | |
161 | static int at32_wdt_settimeout(int time) | |
162 | { | |
163 | /* | |
164 | * All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is | |
165 | * 2 ^ 16 allowing up to 2 seconds timeout. | |
166 | */ | |
167 | if ((time < TIMEOUT_MIN) || (time > TIMEOUT_MAX)) | |
168 | return -EINVAL; | |
169 | ||
c37f2713 AM |
170 | /* |
171 | * Set new watchdog time. It will be used when at32_wdt_start() is | |
172 | * called. | |
173 | */ | |
a9cb3959 HCE |
174 | wdt->timeout = time; |
175 | return 0; | |
176 | } | |
177 | ||
bb133450 HCE |
178 | /* |
179 | * Get the watchdog status. | |
180 | */ | |
181 | static 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): /* fall through */ | |
196 | case WDT_BIT(RCAUSE_JTAG): /* fall through */ | |
197 | case WDT_BIT(RCAUSE_SERP): /* fall through */ | |
198 | default: | |
199 | break; | |
200 | } | |
201 | ||
202 | return status; | |
203 | } | |
204 | ||
a9cb3959 HCE |
205 | static struct watchdog_info at32_wdt_info = { |
206 | .identity = "at32ap700x watchdog", | |
28401140 WVS |
207 | .options = WDIOF_SETTIMEOUT | |
208 | WDIOF_KEEPALIVEPING | | |
209 | WDIOF_MAGICCLOSE, | |
a9cb3959 HCE |
210 | }; |
211 | ||
212 | /* | |
213 | * Handle commands from user-space. | |
214 | */ | |
215 | static int at32_wdt_ioctl(struct inode *inode, 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 | ||
c37f2713 | 223 | switch (cmd) { |
a9cb3959 HCE |
224 | case WDIOC_KEEPALIVE: |
225 | at32_wdt_pat(); | |
226 | ret = 0; | |
227 | break; | |
228 | case WDIOC_GETSUPPORT: | |
229 | ret = copy_to_user(argp, &at32_wdt_info, | |
230 | sizeof(at32_wdt_info)) ? -EFAULT : 0; | |
231 | break; | |
232 | case WDIOC_SETTIMEOUT: | |
233 | ret = get_user(time, p); | |
234 | if (ret) | |
235 | break; | |
236 | ret = at32_wdt_settimeout(time); | |
237 | if (ret) | |
238 | break; | |
239 | /* Enable new time value */ | |
240 | at32_wdt_start(); | |
241 | /* fall through */ | |
242 | case WDIOC_GETTIMEOUT: | |
243 | ret = put_user(wdt->timeout, p); | |
244 | break; | |
bb133450 | 245 | case WDIOC_GETSTATUS: |
a9cb3959 HCE |
246 | ret = put_user(0, p); |
247 | break; | |
bb133450 HCE |
248 | case WDIOC_GETBOOTSTATUS: |
249 | ret = put_user(wdt->boot_status, p); | |
250 | break; | |
a9cb3959 HCE |
251 | case WDIOC_SETOPTIONS: |
252 | ret = get_user(time, p); | |
253 | if (ret) | |
254 | break; | |
255 | if (time & WDIOS_DISABLECARD) | |
256 | at32_wdt_stop(); | |
257 | if (time & WDIOS_ENABLECARD) | |
258 | at32_wdt_start(); | |
259 | ret = 0; | |
260 | break; | |
261 | } | |
262 | ||
263 | return ret; | |
264 | } | |
265 | ||
28401140 WVS |
266 | static ssize_t at32_wdt_write(struct file *file, const char __user *data, |
267 | size_t len, loff_t *ppos) | |
a9cb3959 | 268 | { |
28401140 WVS |
269 | /* See if we got the magic character 'V' and reload the timer */ |
270 | if (len) { | |
271 | if (!nowayout) { | |
272 | size_t i; | |
273 | ||
274 | /* | |
275 | * note: just in case someone wrote the magic | |
276 | * character five months ago... | |
277 | */ | |
278 | expect_release = 0; | |
279 | ||
280 | /* | |
281 | * scan to see whether or not we got the magic | |
282 | * character | |
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 | /* someone wrote to us, we should pat the watchdog */ | |
293 | at32_wdt_pat(); | |
294 | } | |
a9cb3959 HCE |
295 | return len; |
296 | } | |
297 | ||
298 | static const struct file_operations at32_wdt_fops = { | |
299 | .owner = THIS_MODULE, | |
300 | .llseek = no_llseek, | |
301 | .ioctl = at32_wdt_ioctl, | |
302 | .open = at32_wdt_open, | |
303 | .release = at32_wdt_close, | |
304 | .write = at32_wdt_write, | |
305 | }; | |
306 | ||
307 | static 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); | |
47d17763 HCE |
330 | if (!wdt->regs) { |
331 | ret = -ENOMEM; | |
332 | dev_dbg(&pdev->dev, "could not map I/O memory\n"); | |
333 | goto err_free; | |
334 | } | |
bb133450 | 335 | |
e75e6577 | 336 | spin_lock_init(&wdt->io_lock); |
bb133450 HCE |
337 | wdt->boot_status = at32_wdt_get_status(); |
338 | ||
339 | /* Work-around for watchdog silicon errata. */ | |
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 | } | |
a9cb3959 HCE |
348 | wdt->miscdev.minor = WATCHDOG_MINOR; |
349 | wdt->miscdev.name = "watchdog"; | |
350 | wdt->miscdev.fops = &at32_wdt_fops; | |
351 | ||
726c9f61 WVS |
352 | if (at32_wdt_settimeout(timeout)) { |
353 | at32_wdt_settimeout(TIMEOUT_DEFAULT); | |
a9cb3959 HCE |
354 | dev_dbg(&pdev->dev, |
355 | "default timeout invalid, set to %d sec.\n", | |
726c9f61 | 356 | TIMEOUT_DEFAULT); |
a9cb3959 HCE |
357 | } |
358 | ||
359 | ret = misc_register(&wdt->miscdev); | |
360 | if (ret) { | |
361 | dev_dbg(&pdev->dev, "failed to register wdt miscdev\n"); | |
47d17763 | 362 | goto err_iounmap; |
a9cb3959 HCE |
363 | } |
364 | ||
365 | platform_set_drvdata(pdev, wdt); | |
366 | wdt->miscdev.parent = &pdev->dev; | |
28401140 WVS |
367 | dev_info(&pdev->dev, |
368 | "AT32AP700X WDT at 0x%p, timeout %d sec (nowayout=%d)\n", | |
369 | wdt->regs, wdt->timeout, nowayout); | |
a9cb3959 HCE |
370 | |
371 | return 0; | |
372 | ||
47d17763 HCE |
373 | err_iounmap: |
374 | iounmap(wdt->regs); | |
375 | err_free: | |
a9cb3959 HCE |
376 | kfree(wdt); |
377 | wdt = NULL; | |
378 | return ret; | |
379 | } | |
380 | ||
381 | static int __exit at32_wdt_remove(struct platform_device *pdev) | |
382 | { | |
383 | if (wdt && platform_get_drvdata(pdev) == wdt) { | |
28401140 WVS |
384 | /* Stop the timer before we leave */ |
385 | if (!nowayout) | |
386 | at32_wdt_stop(); | |
387 | ||
a9cb3959 | 388 | misc_deregister(&wdt->miscdev); |
ff732316 | 389 | iounmap(wdt->regs); |
a9cb3959 HCE |
390 | kfree(wdt); |
391 | wdt = NULL; | |
392 | platform_set_drvdata(pdev, NULL); | |
393 | } | |
394 | ||
395 | return 0; | |
396 | } | |
397 | ||
398 | static void at32_wdt_shutdown(struct platform_device *pdev) | |
399 | { | |
400 | at32_wdt_stop(); | |
401 | } | |
402 | ||
403 | #ifdef CONFIG_PM | |
404 | static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message) | |
405 | { | |
406 | at32_wdt_stop(); | |
407 | return 0; | |
408 | } | |
409 | ||
410 | static int at32_wdt_resume(struct platform_device *pdev) | |
411 | { | |
412 | if (wdt->users) | |
413 | at32_wdt_start(); | |
414 | return 0; | |
415 | } | |
97a2a2ea AM |
416 | #else |
417 | #define at32_wdt_suspend NULL | |
418 | #define at32_wdt_resume NULL | |
a9cb3959 HCE |
419 | #endif |
420 | ||
421 | static struct platform_driver at32_wdt_driver = { | |
422 | .remove = __exit_p(at32_wdt_remove), | |
a9cb3959 HCE |
423 | .suspend = at32_wdt_suspend, |
424 | .resume = at32_wdt_resume, | |
a9cb3959 HCE |
425 | .driver = { |
426 | .name = "at32_wdt", | |
427 | .owner = THIS_MODULE, | |
428 | }, | |
429 | .shutdown = at32_wdt_shutdown, | |
430 | }; | |
431 | ||
432 | static int __init at32_wdt_init(void) | |
433 | { | |
434 | return platform_driver_probe(&at32_wdt_driver, at32_wdt_probe); | |
435 | } | |
436 | module_init(at32_wdt_init); | |
437 | ||
438 | static void __exit at32_wdt_exit(void) | |
439 | { | |
440 | platform_driver_unregister(&at32_wdt_driver); | |
441 | } | |
442 | module_exit(at32_wdt_exit); | |
443 | ||
444 | MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>"); | |
445 | MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X"); | |
446 | MODULE_LICENSE("GPL"); | |
447 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |