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