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