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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. | |
9 | */ | |
10 | ||
11 | #include <linux/init.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/moduleparam.h> | |
15 | #include <linux/miscdevice.h> | |
16 | #include <linux/fs.h> | |
17 | #include <linux/platform_device.h> | |
18 | #include <linux/watchdog.h> | |
c37f2713 AM |
19 | #include <linux/uaccess.h> |
20 | #include <linux/io.h> | |
e75e6577 | 21 | #include <linux/spinlock.h> |
a9cb3959 HCE |
22 | |
23 | #define TIMEOUT_MIN 1 | |
a9cb3959 | 24 | #define TIMEOUT_MAX 2 |
726c9f61 WVS |
25 | #define TIMEOUT_DEFAULT TIMEOUT_MAX |
26 | ||
27 | /* module parameters */ | |
28 | static int timeout = TIMEOUT_DEFAULT; | |
29 | module_param(timeout, int, 0); | |
30 | MODULE_PARM_DESC(timeout, | |
31 | "Timeout value. Limited to be 1 or 2 seconds. (default=" | |
32 | __MODULE_STRING(TIMEOUT_DEFAULT) ")"); | |
a9cb3959 | 33 | |
28401140 WVS |
34 | static int nowayout = WATCHDOG_NOWAYOUT; |
35 | module_param(nowayout, int, 0); | |
36 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" | |
37 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
38 | ||
a9cb3959 HCE |
39 | /* Watchdog registers and write/read macro */ |
40 | #define WDT_CTRL 0x00 | |
41 | #define WDT_CTRL_EN 0 | |
42 | #define WDT_CTRL_PSEL 8 | |
43 | #define WDT_CTRL_KEY 24 | |
44 | ||
45 | #define WDT_CLR 0x04 | |
46 | ||
47 | #define WDT_BIT(name) (1 << WDT_##name) | |
c0ead7e0 | 48 | #define WDT_BF(name, value) ((value) << WDT_##name) |
a9cb3959 | 49 | |
c0ead7e0 | 50 | #define wdt_readl(dev, reg) \ |
a9cb3959 | 51 | __raw_readl((dev)->regs + WDT_##reg) |
c0ead7e0 | 52 | #define wdt_writel(dev, reg, value) \ |
a9cb3959 HCE |
53 | __raw_writel((value), (dev)->regs + WDT_##reg) |
54 | ||
55 | struct wdt_at32ap700x { | |
56 | void __iomem *regs; | |
e75e6577 | 57 | spinlock_t io_lock; |
a9cb3959 | 58 | int timeout; |
7e2a1498 | 59 | unsigned long users; |
a9cb3959 HCE |
60 | struct miscdevice miscdev; |
61 | }; | |
62 | ||
63 | static struct wdt_at32ap700x *wdt; | |
28401140 | 64 | static char expect_release; |
a9cb3959 HCE |
65 | |
66 | /* | |
67 | * Disable the watchdog. | |
68 | */ | |
c0ead7e0 | 69 | static inline void at32_wdt_stop(void) |
a9cb3959 | 70 | { |
7e2a1498 WVS |
71 | unsigned long psel; |
72 | ||
e75e6577 | 73 | spin_lock(&wdt->io_lock); |
7e2a1498 | 74 | psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f); |
a9cb3959 HCE |
75 | wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55)); |
76 | wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa)); | |
e75e6577 | 77 | spin_unlock(&wdt->io_lock); |
a9cb3959 HCE |
78 | } |
79 | ||
80 | /* | |
81 | * Enable and reset the watchdog. | |
82 | */ | |
c0ead7e0 | 83 | static inline void at32_wdt_start(void) |
a9cb3959 HCE |
84 | { |
85 | /* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */ | |
86 | unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe; | |
87 | ||
e75e6577 | 88 | spin_lock(&wdt->io_lock); |
a9cb3959 HCE |
89 | wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN) |
90 | | WDT_BF(CTRL_PSEL, psel) | |
91 | | WDT_BF(CTRL_KEY, 0x55)); | |
92 | wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN) | |
93 | | WDT_BF(CTRL_PSEL, psel) | |
94 | | WDT_BF(CTRL_KEY, 0xaa)); | |
e75e6577 | 95 | spin_unlock(&wdt->io_lock); |
a9cb3959 HCE |
96 | } |
97 | ||
98 | /* | |
99 | * Pat the watchdog timer. | |
100 | */ | |
c0ead7e0 | 101 | static inline void at32_wdt_pat(void) |
a9cb3959 | 102 | { |
e75e6577 | 103 | spin_lock(&wdt->io_lock); |
a9cb3959 | 104 | wdt_writel(wdt, CLR, 0x42); |
e75e6577 | 105 | spin_unlock(&wdt->io_lock); |
a9cb3959 HCE |
106 | } |
107 | ||
108 | /* | |
109 | * Watchdog device is opened, and watchdog starts running. | |
110 | */ | |
111 | static int at32_wdt_open(struct inode *inode, struct file *file) | |
112 | { | |
113 | if (test_and_set_bit(1, &wdt->users)) | |
114 | return -EBUSY; | |
115 | ||
116 | at32_wdt_start(); | |
117 | return nonseekable_open(inode, file); | |
118 | } | |
119 | ||
120 | /* | |
28401140 | 121 | * Close the watchdog device. |
a9cb3959 HCE |
122 | */ |
123 | static int at32_wdt_close(struct inode *inode, struct file *file) | |
124 | { | |
28401140 WVS |
125 | if (expect_release == 42) { |
126 | at32_wdt_stop(); | |
127 | } else { | |
128 | dev_dbg(wdt->miscdev.parent, | |
129 | "Unexpected close, not stopping watchdog!\n"); | |
130 | at32_wdt_pat(); | |
131 | } | |
a9cb3959 | 132 | clear_bit(1, &wdt->users); |
28401140 | 133 | expect_release = 0; |
a9cb3959 HCE |
134 | return 0; |
135 | } | |
136 | ||
137 | /* | |
138 | * Change the watchdog time interval. | |
139 | */ | |
140 | static int at32_wdt_settimeout(int time) | |
141 | { | |
142 | /* | |
143 | * All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is | |
144 | * 2 ^ 16 allowing up to 2 seconds timeout. | |
145 | */ | |
146 | if ((time < TIMEOUT_MIN) || (time > TIMEOUT_MAX)) | |
147 | return -EINVAL; | |
148 | ||
c37f2713 AM |
149 | /* |
150 | * Set new watchdog time. It will be used when at32_wdt_start() is | |
151 | * called. | |
152 | */ | |
a9cb3959 HCE |
153 | wdt->timeout = time; |
154 | return 0; | |
155 | } | |
156 | ||
157 | static struct watchdog_info at32_wdt_info = { | |
158 | .identity = "at32ap700x watchdog", | |
28401140 WVS |
159 | .options = WDIOF_SETTIMEOUT | |
160 | WDIOF_KEEPALIVEPING | | |
161 | WDIOF_MAGICCLOSE, | |
a9cb3959 HCE |
162 | }; |
163 | ||
164 | /* | |
165 | * Handle commands from user-space. | |
166 | */ | |
167 | static int at32_wdt_ioctl(struct inode *inode, struct file *file, | |
168 | unsigned int cmd, unsigned long arg) | |
169 | { | |
170 | int ret = -ENOTTY; | |
171 | int time; | |
172 | void __user *argp = (void __user *)arg; | |
173 | int __user *p = argp; | |
174 | ||
c37f2713 | 175 | switch (cmd) { |
a9cb3959 HCE |
176 | case WDIOC_KEEPALIVE: |
177 | at32_wdt_pat(); | |
178 | ret = 0; | |
179 | break; | |
180 | case WDIOC_GETSUPPORT: | |
181 | ret = copy_to_user(argp, &at32_wdt_info, | |
182 | sizeof(at32_wdt_info)) ? -EFAULT : 0; | |
183 | break; | |
184 | case WDIOC_SETTIMEOUT: | |
185 | ret = get_user(time, p); | |
186 | if (ret) | |
187 | break; | |
188 | ret = at32_wdt_settimeout(time); | |
189 | if (ret) | |
190 | break; | |
191 | /* Enable new time value */ | |
192 | at32_wdt_start(); | |
193 | /* fall through */ | |
194 | case WDIOC_GETTIMEOUT: | |
195 | ret = put_user(wdt->timeout, p); | |
196 | break; | |
197 | case WDIOC_GETSTATUS: /* fall through */ | |
198 | case WDIOC_GETBOOTSTATUS: | |
199 | ret = put_user(0, p); | |
200 | break; | |
201 | case WDIOC_SETOPTIONS: | |
202 | ret = get_user(time, p); | |
203 | if (ret) | |
204 | break; | |
205 | if (time & WDIOS_DISABLECARD) | |
206 | at32_wdt_stop(); | |
207 | if (time & WDIOS_ENABLECARD) | |
208 | at32_wdt_start(); | |
209 | ret = 0; | |
210 | break; | |
211 | } | |
212 | ||
213 | return ret; | |
214 | } | |
215 | ||
28401140 WVS |
216 | static ssize_t at32_wdt_write(struct file *file, const char __user *data, |
217 | size_t len, loff_t *ppos) | |
a9cb3959 | 218 | { |
28401140 WVS |
219 | /* See if we got the magic character 'V' and reload the timer */ |
220 | if (len) { | |
221 | if (!nowayout) { | |
222 | size_t i; | |
223 | ||
224 | /* | |
225 | * note: just in case someone wrote the magic | |
226 | * character five months ago... | |
227 | */ | |
228 | expect_release = 0; | |
229 | ||
230 | /* | |
231 | * scan to see whether or not we got the magic | |
232 | * character | |
233 | */ | |
234 | for (i = 0; i != len; i++) { | |
235 | char c; | |
236 | if (get_user(c, data+i)) | |
237 | return -EFAULT; | |
238 | if (c == 'V') | |
239 | expect_release = 42; | |
240 | } | |
241 | } | |
242 | /* someone wrote to us, we should pat the watchdog */ | |
243 | at32_wdt_pat(); | |
244 | } | |
a9cb3959 HCE |
245 | return len; |
246 | } | |
247 | ||
248 | static const struct file_operations at32_wdt_fops = { | |
249 | .owner = THIS_MODULE, | |
250 | .llseek = no_llseek, | |
251 | .ioctl = at32_wdt_ioctl, | |
252 | .open = at32_wdt_open, | |
253 | .release = at32_wdt_close, | |
254 | .write = at32_wdt_write, | |
255 | }; | |
256 | ||
257 | static int __init at32_wdt_probe(struct platform_device *pdev) | |
258 | { | |
259 | struct resource *regs; | |
260 | int ret; | |
261 | ||
262 | if (wdt) { | |
263 | dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n"); | |
264 | return -EBUSY; | |
265 | } | |
266 | ||
267 | regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
268 | if (!regs) { | |
269 | dev_dbg(&pdev->dev, "missing mmio resource\n"); | |
270 | return -ENXIO; | |
271 | } | |
272 | ||
273 | wdt = kzalloc(sizeof(struct wdt_at32ap700x), GFP_KERNEL); | |
274 | if (!wdt) { | |
275 | dev_dbg(&pdev->dev, "no memory for wdt structure\n"); | |
276 | return -ENOMEM; | |
277 | } | |
278 | ||
279 | wdt->regs = ioremap(regs->start, regs->end - regs->start + 1); | |
47d17763 HCE |
280 | if (!wdt->regs) { |
281 | ret = -ENOMEM; | |
282 | dev_dbg(&pdev->dev, "could not map I/O memory\n"); | |
283 | goto err_free; | |
284 | } | |
e75e6577 | 285 | spin_lock_init(&wdt->io_lock); |
a9cb3959 HCE |
286 | wdt->users = 0; |
287 | wdt->miscdev.minor = WATCHDOG_MINOR; | |
288 | wdt->miscdev.name = "watchdog"; | |
289 | wdt->miscdev.fops = &at32_wdt_fops; | |
290 | ||
726c9f61 WVS |
291 | if (at32_wdt_settimeout(timeout)) { |
292 | at32_wdt_settimeout(TIMEOUT_DEFAULT); | |
a9cb3959 HCE |
293 | dev_dbg(&pdev->dev, |
294 | "default timeout invalid, set to %d sec.\n", | |
726c9f61 | 295 | TIMEOUT_DEFAULT); |
a9cb3959 HCE |
296 | } |
297 | ||
298 | ret = misc_register(&wdt->miscdev); | |
299 | if (ret) { | |
300 | dev_dbg(&pdev->dev, "failed to register wdt miscdev\n"); | |
47d17763 | 301 | goto err_iounmap; |
a9cb3959 HCE |
302 | } |
303 | ||
304 | platform_set_drvdata(pdev, wdt); | |
305 | wdt->miscdev.parent = &pdev->dev; | |
28401140 WVS |
306 | dev_info(&pdev->dev, |
307 | "AT32AP700X WDT at 0x%p, timeout %d sec (nowayout=%d)\n", | |
308 | wdt->regs, wdt->timeout, nowayout); | |
a9cb3959 HCE |
309 | |
310 | return 0; | |
311 | ||
47d17763 HCE |
312 | err_iounmap: |
313 | iounmap(wdt->regs); | |
314 | err_free: | |
a9cb3959 HCE |
315 | kfree(wdt); |
316 | wdt = NULL; | |
317 | return ret; | |
318 | } | |
319 | ||
320 | static int __exit at32_wdt_remove(struct platform_device *pdev) | |
321 | { | |
322 | if (wdt && platform_get_drvdata(pdev) == wdt) { | |
28401140 WVS |
323 | /* Stop the timer before we leave */ |
324 | if (!nowayout) | |
325 | at32_wdt_stop(); | |
326 | ||
a9cb3959 | 327 | misc_deregister(&wdt->miscdev); |
ff732316 | 328 | iounmap(wdt->regs); |
a9cb3959 HCE |
329 | kfree(wdt); |
330 | wdt = NULL; | |
331 | platform_set_drvdata(pdev, NULL); | |
332 | } | |
333 | ||
334 | return 0; | |
335 | } | |
336 | ||
337 | static void at32_wdt_shutdown(struct platform_device *pdev) | |
338 | { | |
339 | at32_wdt_stop(); | |
340 | } | |
341 | ||
342 | #ifdef CONFIG_PM | |
343 | static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message) | |
344 | { | |
345 | at32_wdt_stop(); | |
346 | return 0; | |
347 | } | |
348 | ||
349 | static int at32_wdt_resume(struct platform_device *pdev) | |
350 | { | |
351 | if (wdt->users) | |
352 | at32_wdt_start(); | |
353 | return 0; | |
354 | } | |
97a2a2ea AM |
355 | #else |
356 | #define at32_wdt_suspend NULL | |
357 | #define at32_wdt_resume NULL | |
a9cb3959 HCE |
358 | #endif |
359 | ||
360 | static struct platform_driver at32_wdt_driver = { | |
361 | .remove = __exit_p(at32_wdt_remove), | |
a9cb3959 HCE |
362 | .suspend = at32_wdt_suspend, |
363 | .resume = at32_wdt_resume, | |
a9cb3959 HCE |
364 | .driver = { |
365 | .name = "at32_wdt", | |
366 | .owner = THIS_MODULE, | |
367 | }, | |
368 | .shutdown = at32_wdt_shutdown, | |
369 | }; | |
370 | ||
371 | static int __init at32_wdt_init(void) | |
372 | { | |
373 | return platform_driver_probe(&at32_wdt_driver, at32_wdt_probe); | |
374 | } | |
375 | module_init(at32_wdt_init); | |
376 | ||
377 | static void __exit at32_wdt_exit(void) | |
378 | { | |
379 | platform_driver_unregister(&at32_wdt_driver); | |
380 | } | |
381 | module_exit(at32_wdt_exit); | |
382 | ||
383 | MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>"); | |
384 | MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X"); | |
385 | MODULE_LICENSE("GPL"); | |
386 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |