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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 | ||
474ef121 OS |
49 | #define IMX2_WDT_WRSR 0x04 /* Reset Status Register */ |
50 | #define IMX2_WDT_WRSR_TOUT (1 << 1) /* -> Reset due to Timeout */ | |
51 | ||
bb2fd8a8 WS |
52 | #define IMX2_WDT_MAX_TIME 128 |
53 | #define IMX2_WDT_DEFAULT_TIME 60 /* in seconds */ | |
54 | ||
55 | #define WDOG_SEC_TO_COUNT(s) ((s * 2 - 1) << 8) | |
56 | ||
57 | #define IMX2_WDT_STATUS_OPEN 0 | |
58 | #define IMX2_WDT_STATUS_STARTED 1 | |
59 | #define IMX2_WDT_EXPECT_CLOSE 2 | |
60 | ||
61 | static struct { | |
62 | struct clk *clk; | |
63 | void __iomem *base; | |
64 | unsigned timeout; | |
65 | unsigned long status; | |
66 | struct timer_list timer; /* Pings the watchdog when closed */ | |
67 | } imx2_wdt; | |
68 | ||
69 | static struct miscdevice imx2_wdt_miscdev; | |
70 | ||
86a1e189 WVS |
71 | static bool nowayout = WATCHDOG_NOWAYOUT; |
72 | module_param(nowayout, bool, 0); | |
bb2fd8a8 WS |
73 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
74 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
75 | ||
76 | ||
77 | static unsigned timeout = IMX2_WDT_DEFAULT_TIME; | |
78 | module_param(timeout, uint, 0); | |
79 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" | |
80 | __MODULE_STRING(IMX2_WDT_DEFAULT_TIME) ")"); | |
81 | ||
82 | static const struct watchdog_info imx2_wdt_info = { | |
83 | .identity = "imx2+ watchdog", | |
84 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, | |
85 | }; | |
86 | ||
87 | static inline void imx2_wdt_setup(void) | |
88 | { | |
89 | u16 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WCR); | |
90 | ||
91 | /* Strip the old watchdog Time-Out value */ | |
92 | val &= ~IMX2_WDT_WCR_WT; | |
93 | /* Generate reset if WDOG times out */ | |
94 | val &= ~IMX2_WDT_WCR_WRE; | |
95 | /* Keep Watchdog Disabled */ | |
96 | val &= ~IMX2_WDT_WCR_WDE; | |
97 | /* Set the watchdog's Time-Out value */ | |
98 | val |= WDOG_SEC_TO_COUNT(imx2_wdt.timeout); | |
99 | ||
100 | __raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR); | |
101 | ||
102 | /* enable the watchdog */ | |
103 | val |= IMX2_WDT_WCR_WDE; | |
104 | __raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR); | |
105 | } | |
106 | ||
107 | static inline void imx2_wdt_ping(void) | |
108 | { | |
109 | __raw_writew(IMX2_WDT_SEQ1, imx2_wdt.base + IMX2_WDT_WSR); | |
110 | __raw_writew(IMX2_WDT_SEQ2, imx2_wdt.base + IMX2_WDT_WSR); | |
111 | } | |
112 | ||
113 | static void imx2_wdt_timer_ping(unsigned long arg) | |
114 | { | |
115 | /* ping it every imx2_wdt.timeout / 2 seconds to prevent reboot */ | |
116 | imx2_wdt_ping(); | |
117 | mod_timer(&imx2_wdt.timer, jiffies + imx2_wdt.timeout * HZ / 2); | |
118 | } | |
119 | ||
120 | static void imx2_wdt_start(void) | |
121 | { | |
122 | if (!test_and_set_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) { | |
123 | /* at our first start we enable clock and do initialisations */ | |
124 | clk_enable(imx2_wdt.clk); | |
125 | ||
126 | imx2_wdt_setup(); | |
127 | } else /* delete the timer that pings the watchdog after close */ | |
128 | del_timer_sync(&imx2_wdt.timer); | |
129 | ||
130 | /* Watchdog is enabled - time to reload the timeout value */ | |
131 | imx2_wdt_ping(); | |
132 | } | |
133 | ||
134 | static void imx2_wdt_stop(void) | |
135 | { | |
136 | /* we don't need a clk_disable, it cannot be disabled once started. | |
137 | * We use a timer to ping the watchdog while /dev/watchdog is closed */ | |
138 | imx2_wdt_timer_ping(0); | |
139 | } | |
140 | ||
141 | static void imx2_wdt_set_timeout(int new_timeout) | |
142 | { | |
143 | u16 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WCR); | |
144 | ||
145 | /* set the new timeout value in the WSR */ | |
146 | val &= ~IMX2_WDT_WCR_WT; | |
147 | val |= WDOG_SEC_TO_COUNT(new_timeout); | |
148 | __raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR); | |
149 | } | |
150 | ||
151 | static int imx2_wdt_open(struct inode *inode, struct file *file) | |
152 | { | |
153 | if (test_and_set_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status)) | |
154 | return -EBUSY; | |
155 | ||
156 | imx2_wdt_start(); | |
157 | return nonseekable_open(inode, file); | |
158 | } | |
159 | ||
160 | static int imx2_wdt_close(struct inode *inode, struct file *file) | |
161 | { | |
162 | if (test_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status) && !nowayout) | |
163 | imx2_wdt_stop(); | |
164 | else { | |
165 | dev_crit(imx2_wdt_miscdev.parent, | |
166 | "Unexpected close: Expect reboot!\n"); | |
167 | imx2_wdt_ping(); | |
168 | } | |
169 | ||
170 | clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status); | |
171 | clear_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status); | |
172 | return 0; | |
173 | } | |
174 | ||
175 | static long imx2_wdt_ioctl(struct file *file, unsigned int cmd, | |
176 | unsigned long arg) | |
177 | { | |
178 | void __user *argp = (void __user *)arg; | |
179 | int __user *p = argp; | |
180 | int new_value; | |
474ef121 | 181 | u16 val; |
bb2fd8a8 WS |
182 | |
183 | switch (cmd) { | |
184 | case WDIOC_GETSUPPORT: | |
185 | return copy_to_user(argp, &imx2_wdt_info, | |
186 | sizeof(struct watchdog_info)) ? -EFAULT : 0; | |
187 | ||
188 | case WDIOC_GETSTATUS: | |
bb2fd8a8 WS |
189 | return put_user(0, p); |
190 | ||
474ef121 OS |
191 | case WDIOC_GETBOOTSTATUS: |
192 | val = __raw_readw(imx2_wdt.base + IMX2_WDT_WRSR); | |
193 | new_value = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0; | |
194 | return put_user(new_value, p); | |
195 | ||
bb2fd8a8 WS |
196 | case WDIOC_KEEPALIVE: |
197 | imx2_wdt_ping(); | |
198 | return 0; | |
199 | ||
200 | case WDIOC_SETTIMEOUT: | |
201 | if (get_user(new_value, p)) | |
202 | return -EFAULT; | |
203 | if ((new_value < 1) || (new_value > IMX2_WDT_MAX_TIME)) | |
204 | return -EINVAL; | |
205 | imx2_wdt_set_timeout(new_value); | |
206 | imx2_wdt.timeout = new_value; | |
207 | imx2_wdt_ping(); | |
208 | ||
209 | /* Fallthrough to return current value */ | |
210 | case WDIOC_GETTIMEOUT: | |
211 | return put_user(imx2_wdt.timeout, p); | |
212 | ||
213 | default: | |
214 | return -ENOTTY; | |
215 | } | |
216 | } | |
217 | ||
218 | static ssize_t imx2_wdt_write(struct file *file, const char __user *data, | |
219 | size_t len, loff_t *ppos) | |
220 | { | |
221 | size_t i; | |
222 | char c; | |
223 | ||
224 | if (len == 0) /* Can we see this even ? */ | |
225 | return 0; | |
226 | ||
227 | clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status); | |
228 | /* scan to see whether or not we got the magic character */ | |
229 | for (i = 0; i != len; i++) { | |
230 | if (get_user(c, data + i)) | |
231 | return -EFAULT; | |
232 | if (c == 'V') | |
233 | set_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status); | |
234 | } | |
235 | ||
236 | imx2_wdt_ping(); | |
237 | return len; | |
238 | } | |
239 | ||
240 | static const struct file_operations imx2_wdt_fops = { | |
241 | .owner = THIS_MODULE, | |
242 | .llseek = no_llseek, | |
243 | .unlocked_ioctl = imx2_wdt_ioctl, | |
244 | .open = imx2_wdt_open, | |
245 | .release = imx2_wdt_close, | |
246 | .write = imx2_wdt_write, | |
247 | }; | |
248 | ||
249 | static struct miscdevice imx2_wdt_miscdev = { | |
250 | .minor = WATCHDOG_MINOR, | |
251 | .name = "watchdog", | |
252 | .fops = &imx2_wdt_fops, | |
253 | }; | |
254 | ||
255 | static int __init imx2_wdt_probe(struct platform_device *pdev) | |
256 | { | |
257 | int ret; | |
bb2fd8a8 WS |
258 | struct resource *res; |
259 | ||
260 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
261 | if (!res) { | |
262 | dev_err(&pdev->dev, "can't get device resources\n"); | |
263 | return -ENODEV; | |
264 | } | |
265 | ||
5d32d486 | 266 | imx2_wdt.base = devm_request_and_ioremap(&pdev->dev, res); |
bb2fd8a8 WS |
267 | if (!imx2_wdt.base) { |
268 | dev_err(&pdev->dev, "ioremap failed\n"); | |
269 | return -ENOMEM; | |
270 | } | |
271 | ||
2c1f4672 | 272 | imx2_wdt.clk = clk_get(&pdev->dev, NULL); |
bb2fd8a8 WS |
273 | if (IS_ERR(imx2_wdt.clk)) { |
274 | dev_err(&pdev->dev, "can't get Watchdog clock\n"); | |
275 | return PTR_ERR(imx2_wdt.clk); | |
276 | } | |
277 | ||
278 | imx2_wdt.timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME); | |
279 | if (imx2_wdt.timeout != timeout) | |
280 | dev_warn(&pdev->dev, "Initial timeout out of range! " | |
281 | "Clamped from %u to %u\n", timeout, imx2_wdt.timeout); | |
282 | ||
283 | setup_timer(&imx2_wdt.timer, imx2_wdt_timer_ping, 0); | |
284 | ||
285 | imx2_wdt_miscdev.parent = &pdev->dev; | |
286 | ret = misc_register(&imx2_wdt_miscdev); | |
287 | if (ret) | |
288 | goto fail; | |
289 | ||
290 | dev_info(&pdev->dev, | |
291 | "IMX2+ Watchdog Timer enabled. timeout=%ds (nowayout=%d)\n", | |
292 | imx2_wdt.timeout, nowayout); | |
293 | return 0; | |
294 | ||
295 | fail: | |
296 | imx2_wdt_miscdev.parent = NULL; | |
297 | clk_put(imx2_wdt.clk); | |
298 | return ret; | |
299 | } | |
300 | ||
301 | static int __exit imx2_wdt_remove(struct platform_device *pdev) | |
302 | { | |
303 | misc_deregister(&imx2_wdt_miscdev); | |
304 | ||
305 | if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) { | |
306 | del_timer_sync(&imx2_wdt.timer); | |
307 | ||
308 | dev_crit(imx2_wdt_miscdev.parent, | |
309 | "Device removed: Expect reboot!\n"); | |
310 | } else | |
311 | clk_put(imx2_wdt.clk); | |
312 | ||
313 | imx2_wdt_miscdev.parent = NULL; | |
314 | return 0; | |
315 | } | |
316 | ||
317 | static void imx2_wdt_shutdown(struct platform_device *pdev) | |
318 | { | |
319 | if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) { | |
320 | /* we are running, we need to delete the timer but will give | |
321 | * max timeout before reboot will take place */ | |
322 | del_timer_sync(&imx2_wdt.timer); | |
323 | imx2_wdt_set_timeout(IMX2_WDT_MAX_TIME); | |
324 | imx2_wdt_ping(); | |
325 | ||
326 | dev_crit(imx2_wdt_miscdev.parent, | |
327 | "Device shutdown: Expect reboot!\n"); | |
328 | } | |
329 | } | |
330 | ||
f5a427ee SG |
331 | static const struct of_device_id imx2_wdt_dt_ids[] = { |
332 | { .compatible = "fsl,imx21-wdt", }, | |
333 | { /* sentinel */ } | |
334 | }; | |
335 | ||
bb2fd8a8 | 336 | static struct platform_driver imx2_wdt_driver = { |
bb2fd8a8 WS |
337 | .remove = __exit_p(imx2_wdt_remove), |
338 | .shutdown = imx2_wdt_shutdown, | |
339 | .driver = { | |
340 | .name = DRIVER_NAME, | |
341 | .owner = THIS_MODULE, | |
f5a427ee | 342 | .of_match_table = imx2_wdt_dt_ids, |
bb2fd8a8 WS |
343 | }, |
344 | }; | |
345 | ||
346 | static int __init imx2_wdt_init(void) | |
347 | { | |
348 | return platform_driver_probe(&imx2_wdt_driver, imx2_wdt_probe); | |
349 | } | |
350 | module_init(imx2_wdt_init); | |
351 | ||
352 | static void __exit imx2_wdt_exit(void) | |
353 | { | |
354 | platform_driver_unregister(&imx2_wdt_driver); | |
355 | } | |
356 | module_exit(imx2_wdt_exit); | |
357 | ||
358 | MODULE_AUTHOR("Wolfram Sang"); | |
359 | MODULE_DESCRIPTION("Watchdog driver for IMX2 and later"); | |
360 | MODULE_LICENSE("GPL v2"); | |
361 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
362 | MODULE_ALIAS("platform:" DRIVER_NAME); |