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bb2fd8a8 WS |
1 | /* |
2 | * Watchdog driver for IMX2 and later processors | |
3 | * | |
4 | * Copyright (C) 2010 Wolfram Sang, Pengutronix e.K. <w.sang@pengutronix.de> | |
5 | * | |
6 | * some parts adapted by similar drivers from Darius Augulis and Vladimir | |
7 | * Zapolskiy, additional improvements by Wim Van Sebroeck. | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify it | |
10 | * under the terms of the GNU General Public License version 2 as published by | |
11 | * the Free Software Foundation. | |
12 | * | |
13 | * NOTE: MX1 has a slightly different Watchdog than MX2 and later: | |
14 | * | |
15 | * MX1: MX2+: | |
16 | * ---- ----- | |
17 | * Registers: 32-bit 16-bit | |
18 | * Stopable timer: Yes No | |
19 | * Need to enable clk: No Yes | |
20 | * Halt on suspend: Manual Can be automatic | |
21 | */ | |
22 | ||
23 | #include <linux/init.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/miscdevice.h> | |
26 | #include <linux/module.h> | |
27 | #include <linux/moduleparam.h> | |
28 | #include <linux/platform_device.h> | |
29 | #include <linux/watchdog.h> | |
30 | #include <linux/clk.h> | |
31 | #include <linux/fs.h> | |
32 | #include <linux/io.h> | |
33 | #include <linux/uaccess.h> | |
34 | #include <linux/timer.h> | |
35 | #include <linux/jiffies.h> | |
36 | #include <mach/hardware.h> | |
37 | ||
38 | #define DRIVER_NAME "imx2-wdt" | |
39 | ||
40 | #define IMX2_WDT_WCR 0x00 /* Control Register */ | |
41 | #define IMX2_WDT_WCR_WT (0xFF << 8) /* -> Watchdog Timeout Field */ | |
42 | #define IMX2_WDT_WCR_WRE (1 << 3) /* -> WDOG Reset Enable */ | |
43 | #define IMX2_WDT_WCR_WDE (1 << 2) /* -> Watchdog Enable */ | |
44 | ||
45 | #define IMX2_WDT_WSR 0x02 /* Service Register */ | |
46 | #define IMX2_WDT_SEQ1 0x5555 /* -> service sequence 1 */ | |
47 | #define IMX2_WDT_SEQ2 0xAAAA /* -> service sequence 2 */ | |
48 | ||
49 | #define IMX2_WDT_MAX_TIME 128 | |
50 | #define IMX2_WDT_DEFAULT_TIME 60 /* in seconds */ | |
51 | ||
52 | #define WDOG_SEC_TO_COUNT(s) ((s * 2 - 1) << 8) | |
53 | ||
54 | #define IMX2_WDT_STATUS_OPEN 0 | |
55 | #define IMX2_WDT_STATUS_STARTED 1 | |
56 | #define IMX2_WDT_EXPECT_CLOSE 2 | |
57 | ||
58 | static struct { | |
59 | struct clk *clk; | |
60 | void __iomem *base; | |
61 | unsigned timeout; | |
62 | unsigned long status; | |
63 | struct timer_list timer; /* Pings the watchdog when closed */ | |
64 | } imx2_wdt; | |
65 | ||
66 | static struct miscdevice imx2_wdt_miscdev; | |
67 | ||
68 | static int nowayout = WATCHDOG_NOWAYOUT; | |
69 | module_param(nowayout, int, 0); | |
70 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" | |
71 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
72 | ||
73 | ||
74 | static unsigned timeout = IMX2_WDT_DEFAULT_TIME; | |
75 | module_param(timeout, uint, 0); | |
76 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" | |
77 | __MODULE_STRING(IMX2_WDT_DEFAULT_TIME) ")"); | |
78 | ||
79 | static const struct watchdog_info imx2_wdt_info = { | |
80 | .identity = "imx2+ watchdog", | |
81 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, | |
82 | }; | |
83 | ||
84 | static inline void imx2_wdt_setup(void) | |
85 | { | |
86 | u16 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WCR); | |
87 | ||
88 | /* Strip the old watchdog Time-Out value */ | |
89 | val &= ~IMX2_WDT_WCR_WT; | |
90 | /* Generate reset if WDOG times out */ | |
91 | val &= ~IMX2_WDT_WCR_WRE; | |
92 | /* Keep Watchdog Disabled */ | |
93 | val &= ~IMX2_WDT_WCR_WDE; | |
94 | /* Set the watchdog's Time-Out value */ | |
95 | val |= WDOG_SEC_TO_COUNT(imx2_wdt.timeout); | |
96 | ||
97 | __raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR); | |
98 | ||
99 | /* enable the watchdog */ | |
100 | val |= IMX2_WDT_WCR_WDE; | |
101 | __raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR); | |
102 | } | |
103 | ||
104 | static inline void imx2_wdt_ping(void) | |
105 | { | |
106 | __raw_writew(IMX2_WDT_SEQ1, imx2_wdt.base + IMX2_WDT_WSR); | |
107 | __raw_writew(IMX2_WDT_SEQ2, imx2_wdt.base + IMX2_WDT_WSR); | |
108 | } | |
109 | ||
110 | static void imx2_wdt_timer_ping(unsigned long arg) | |
111 | { | |
112 | /* ping it every imx2_wdt.timeout / 2 seconds to prevent reboot */ | |
113 | imx2_wdt_ping(); | |
114 | mod_timer(&imx2_wdt.timer, jiffies + imx2_wdt.timeout * HZ / 2); | |
115 | } | |
116 | ||
117 | static void imx2_wdt_start(void) | |
118 | { | |
119 | if (!test_and_set_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) { | |
120 | /* at our first start we enable clock and do initialisations */ | |
121 | clk_enable(imx2_wdt.clk); | |
122 | ||
123 | imx2_wdt_setup(); | |
124 | } else /* delete the timer that pings the watchdog after close */ | |
125 | del_timer_sync(&imx2_wdt.timer); | |
126 | ||
127 | /* Watchdog is enabled - time to reload the timeout value */ | |
128 | imx2_wdt_ping(); | |
129 | } | |
130 | ||
131 | static void imx2_wdt_stop(void) | |
132 | { | |
133 | /* we don't need a clk_disable, it cannot be disabled once started. | |
134 | * We use a timer to ping the watchdog while /dev/watchdog is closed */ | |
135 | imx2_wdt_timer_ping(0); | |
136 | } | |
137 | ||
138 | static void imx2_wdt_set_timeout(int new_timeout) | |
139 | { | |
140 | u16 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WCR); | |
141 | ||
142 | /* set the new timeout value in the WSR */ | |
143 | val &= ~IMX2_WDT_WCR_WT; | |
144 | val |= WDOG_SEC_TO_COUNT(new_timeout); | |
145 | __raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR); | |
146 | } | |
147 | ||
148 | static int imx2_wdt_open(struct inode *inode, struct file *file) | |
149 | { | |
150 | if (test_and_set_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status)) | |
151 | return -EBUSY; | |
152 | ||
153 | imx2_wdt_start(); | |
154 | return nonseekable_open(inode, file); | |
155 | } | |
156 | ||
157 | static int imx2_wdt_close(struct inode *inode, struct file *file) | |
158 | { | |
159 | if (test_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status) && !nowayout) | |
160 | imx2_wdt_stop(); | |
161 | else { | |
162 | dev_crit(imx2_wdt_miscdev.parent, | |
163 | "Unexpected close: Expect reboot!\n"); | |
164 | imx2_wdt_ping(); | |
165 | } | |
166 | ||
167 | clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status); | |
168 | clear_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status); | |
169 | return 0; | |
170 | } | |
171 | ||
172 | static long imx2_wdt_ioctl(struct file *file, unsigned int cmd, | |
173 | unsigned long arg) | |
174 | { | |
175 | void __user *argp = (void __user *)arg; | |
176 | int __user *p = argp; | |
177 | int new_value; | |
178 | ||
179 | switch (cmd) { | |
180 | case WDIOC_GETSUPPORT: | |
181 | return copy_to_user(argp, &imx2_wdt_info, | |
182 | sizeof(struct watchdog_info)) ? -EFAULT : 0; | |
183 | ||
184 | case WDIOC_GETSTATUS: | |
185 | case WDIOC_GETBOOTSTATUS: | |
186 | return put_user(0, p); | |
187 | ||
188 | case WDIOC_KEEPALIVE: | |
189 | imx2_wdt_ping(); | |
190 | return 0; | |
191 | ||
192 | case WDIOC_SETTIMEOUT: | |
193 | if (get_user(new_value, p)) | |
194 | return -EFAULT; | |
195 | if ((new_value < 1) || (new_value > IMX2_WDT_MAX_TIME)) | |
196 | return -EINVAL; | |
197 | imx2_wdt_set_timeout(new_value); | |
198 | imx2_wdt.timeout = new_value; | |
199 | imx2_wdt_ping(); | |
200 | ||
201 | /* Fallthrough to return current value */ | |
202 | case WDIOC_GETTIMEOUT: | |
203 | return put_user(imx2_wdt.timeout, p); | |
204 | ||
205 | default: | |
206 | return -ENOTTY; | |
207 | } | |
208 | } | |
209 | ||
210 | static ssize_t imx2_wdt_write(struct file *file, const char __user *data, | |
211 | size_t len, loff_t *ppos) | |
212 | { | |
213 | size_t i; | |
214 | char c; | |
215 | ||
216 | if (len == 0) /* Can we see this even ? */ | |
217 | return 0; | |
218 | ||
219 | clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status); | |
220 | /* scan to see whether or not we got the magic character */ | |
221 | for (i = 0; i != len; i++) { | |
222 | if (get_user(c, data + i)) | |
223 | return -EFAULT; | |
224 | if (c == 'V') | |
225 | set_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status); | |
226 | } | |
227 | ||
228 | imx2_wdt_ping(); | |
229 | return len; | |
230 | } | |
231 | ||
232 | static const struct file_operations imx2_wdt_fops = { | |
233 | .owner = THIS_MODULE, | |
234 | .llseek = no_llseek, | |
235 | .unlocked_ioctl = imx2_wdt_ioctl, | |
236 | .open = imx2_wdt_open, | |
237 | .release = imx2_wdt_close, | |
238 | .write = imx2_wdt_write, | |
239 | }; | |
240 | ||
241 | static struct miscdevice imx2_wdt_miscdev = { | |
242 | .minor = WATCHDOG_MINOR, | |
243 | .name = "watchdog", | |
244 | .fops = &imx2_wdt_fops, | |
245 | }; | |
246 | ||
247 | static int __init imx2_wdt_probe(struct platform_device *pdev) | |
248 | { | |
249 | int ret; | |
250 | int res_size; | |
251 | struct resource *res; | |
252 | ||
253 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
254 | if (!res) { | |
255 | dev_err(&pdev->dev, "can't get device resources\n"); | |
256 | return -ENODEV; | |
257 | } | |
258 | ||
259 | res_size = resource_size(res); | |
260 | if (!devm_request_mem_region(&pdev->dev, res->start, res_size, | |
261 | res->name)) { | |
262 | dev_err(&pdev->dev, "can't allocate %d bytes at %d address\n", | |
263 | res_size, res->start); | |
264 | return -ENOMEM; | |
265 | } | |
266 | ||
267 | imx2_wdt.base = devm_ioremap_nocache(&pdev->dev, res->start, res_size); | |
268 | if (!imx2_wdt.base) { | |
269 | dev_err(&pdev->dev, "ioremap failed\n"); | |
270 | return -ENOMEM; | |
271 | } | |
272 | ||
2c1f4672 | 273 | imx2_wdt.clk = clk_get(&pdev->dev, NULL); |
bb2fd8a8 WS |
274 | if (IS_ERR(imx2_wdt.clk)) { |
275 | dev_err(&pdev->dev, "can't get Watchdog clock\n"); | |
276 | return PTR_ERR(imx2_wdt.clk); | |
277 | } | |
278 | ||
279 | imx2_wdt.timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME); | |
280 | if (imx2_wdt.timeout != timeout) | |
281 | dev_warn(&pdev->dev, "Initial timeout out of range! " | |
282 | "Clamped from %u to %u\n", timeout, imx2_wdt.timeout); | |
283 | ||
284 | setup_timer(&imx2_wdt.timer, imx2_wdt_timer_ping, 0); | |
285 | ||
286 | imx2_wdt_miscdev.parent = &pdev->dev; | |
287 | ret = misc_register(&imx2_wdt_miscdev); | |
288 | if (ret) | |
289 | goto fail; | |
290 | ||
291 | dev_info(&pdev->dev, | |
292 | "IMX2+ Watchdog Timer enabled. timeout=%ds (nowayout=%d)\n", | |
293 | imx2_wdt.timeout, nowayout); | |
294 | return 0; | |
295 | ||
296 | fail: | |
297 | imx2_wdt_miscdev.parent = NULL; | |
298 | clk_put(imx2_wdt.clk); | |
299 | return ret; | |
300 | } | |
301 | ||
302 | static int __exit imx2_wdt_remove(struct platform_device *pdev) | |
303 | { | |
304 | misc_deregister(&imx2_wdt_miscdev); | |
305 | ||
306 | if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) { | |
307 | del_timer_sync(&imx2_wdt.timer); | |
308 | ||
309 | dev_crit(imx2_wdt_miscdev.parent, | |
310 | "Device removed: Expect reboot!\n"); | |
311 | } else | |
312 | clk_put(imx2_wdt.clk); | |
313 | ||
314 | imx2_wdt_miscdev.parent = NULL; | |
315 | return 0; | |
316 | } | |
317 | ||
318 | static void imx2_wdt_shutdown(struct platform_device *pdev) | |
319 | { | |
320 | if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) { | |
321 | /* we are running, we need to delete the timer but will give | |
322 | * max timeout before reboot will take place */ | |
323 | del_timer_sync(&imx2_wdt.timer); | |
324 | imx2_wdt_set_timeout(IMX2_WDT_MAX_TIME); | |
325 | imx2_wdt_ping(); | |
326 | ||
327 | dev_crit(imx2_wdt_miscdev.parent, | |
328 | "Device shutdown: Expect reboot!\n"); | |
329 | } | |
330 | } | |
331 | ||
332 | static struct platform_driver imx2_wdt_driver = { | |
bb2fd8a8 WS |
333 | .remove = __exit_p(imx2_wdt_remove), |
334 | .shutdown = imx2_wdt_shutdown, | |
335 | .driver = { | |
336 | .name = DRIVER_NAME, | |
337 | .owner = THIS_MODULE, | |
338 | }, | |
339 | }; | |
340 | ||
341 | static int __init imx2_wdt_init(void) | |
342 | { | |
343 | return platform_driver_probe(&imx2_wdt_driver, imx2_wdt_probe); | |
344 | } | |
345 | module_init(imx2_wdt_init); | |
346 | ||
347 | static void __exit imx2_wdt_exit(void) | |
348 | { | |
349 | platform_driver_unregister(&imx2_wdt_driver); | |
350 | } | |
351 | module_exit(imx2_wdt_exit); | |
352 | ||
353 | MODULE_AUTHOR("Wolfram Sang"); | |
354 | MODULE_DESCRIPTION("Watchdog driver for IMX2 and later"); | |
355 | MODULE_LICENSE("GPL v2"); | |
356 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
357 | MODULE_ALIAS("platform:" DRIVER_NAME); |