]>
Commit | Line | Data |
---|---|---|
e6bb42e3 RC |
1 | /* |
2 | * Watchdog driver for Atmel AT91SAM9x processors. | |
3 | * | |
4 | * Copyright (C) 2008 Renaud CERRATO r.cerrato@til-technologies.fr | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | /* | |
13 | * The Watchdog Timer Mode Register can be only written to once. If the | |
14 | * timeout need to be set from Linux, be sure that the bootstrap or the | |
15 | * bootloader doesn't write to this register. | |
16 | */ | |
17 | ||
27c766aa JP |
18 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
19 | ||
e6bb42e3 RC |
20 | #include <linux/errno.h> |
21 | #include <linux/fs.h> | |
22 | #include <linux/init.h> | |
2af29b78 | 23 | #include <linux/io.h> |
e6bb42e3 RC |
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/types.h> | |
30 | #include <linux/watchdog.h> | |
31 | #include <linux/jiffies.h> | |
32 | #include <linux/timer.h> | |
33 | #include <linux/bitops.h> | |
34 | #include <linux/uaccess.h> | |
35 | ||
e7b39145 | 36 | #include "at91sam9_wdt.h" |
e6bb42e3 RC |
37 | |
38 | #define DRV_NAME "AT91SAM9 Watchdog" | |
39 | ||
c1c30a29 JCPV |
40 | #define wdt_read(field) \ |
41 | __raw_readl(at91wdt_private.base + field) | |
42 | #define wdt_write(field, val) \ | |
43 | __raw_writel((val), at91wdt_private.base + field) | |
44 | ||
e6bb42e3 RC |
45 | /* AT91SAM9 watchdog runs a 12bit counter @ 256Hz, |
46 | * use this to convert a watchdog | |
47 | * value from/to milliseconds. | |
48 | */ | |
49 | #define ms_to_ticks(t) (((t << 8) / 1000) - 1) | |
50 | #define ticks_to_ms(t) (((t + 1) * 1000) >> 8) | |
51 | ||
52 | /* Hardware timeout in seconds */ | |
53 | #define WDT_HW_TIMEOUT 2 | |
54 | ||
55 | /* Timer heartbeat (500ms) */ | |
56 | #define WDT_TIMEOUT (HZ/2) | |
57 | ||
58 | /* User land timeout */ | |
59 | #define WDT_HEARTBEAT 15 | |
60 | static int heartbeat = WDT_HEARTBEAT; | |
61 | module_param(heartbeat, int, 0); | |
62 | MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. " | |
63 | "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")"); | |
64 | ||
65 | static int nowayout = WATCHDOG_NOWAYOUT; | |
66 | module_param(nowayout, int, 0); | |
67 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " | |
68 | "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
69 | ||
70 | static void at91_ping(unsigned long data); | |
71 | ||
72 | static struct { | |
c1c30a29 | 73 | void __iomem *base; |
e6bb42e3 RC |
74 | unsigned long next_heartbeat; /* the next_heartbeat for the timer */ |
75 | unsigned long open; | |
76 | char expect_close; | |
77 | struct timer_list timer; /* The timer that pings the watchdog */ | |
78 | } at91wdt_private; | |
79 | ||
80 | /* ......................................................................... */ | |
81 | ||
82 | ||
83 | /* | |
84 | * Reload the watchdog timer. (ie, pat the watchdog) | |
85 | */ | |
86 | static inline void at91_wdt_reset(void) | |
87 | { | |
c1c30a29 | 88 | wdt_write(AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT); |
e6bb42e3 RC |
89 | } |
90 | ||
91 | /* | |
92 | * Timer tick | |
93 | */ | |
94 | static void at91_ping(unsigned long data) | |
95 | { | |
96 | if (time_before(jiffies, at91wdt_private.next_heartbeat) || | |
97 | (!nowayout && !at91wdt_private.open)) { | |
98 | at91_wdt_reset(); | |
99 | mod_timer(&at91wdt_private.timer, jiffies + WDT_TIMEOUT); | |
100 | } else | |
27c766aa | 101 | pr_crit("I will reset your machine !\n"); |
e6bb42e3 RC |
102 | } |
103 | ||
104 | /* | |
105 | * Watchdog device is opened, and watchdog starts running. | |
106 | */ | |
107 | static int at91_wdt_open(struct inode *inode, struct file *file) | |
108 | { | |
109 | if (test_and_set_bit(0, &at91wdt_private.open)) | |
110 | return -EBUSY; | |
111 | ||
112 | at91wdt_private.next_heartbeat = jiffies + heartbeat * HZ; | |
113 | mod_timer(&at91wdt_private.timer, jiffies + WDT_TIMEOUT); | |
114 | ||
115 | return nonseekable_open(inode, file); | |
116 | } | |
117 | ||
118 | /* | |
119 | * Close the watchdog device. | |
120 | */ | |
121 | static int at91_wdt_close(struct inode *inode, struct file *file) | |
122 | { | |
123 | clear_bit(0, &at91wdt_private.open); | |
124 | ||
125 | /* stop internal ping */ | |
126 | if (!at91wdt_private.expect_close) | |
127 | del_timer(&at91wdt_private.timer); | |
128 | ||
129 | at91wdt_private.expect_close = 0; | |
130 | return 0; | |
131 | } | |
132 | ||
133 | /* | |
134 | * Set the watchdog time interval in 1/256Hz (write-once) | |
135 | * Counter is 12 bit. | |
136 | */ | |
137 | static int at91_wdt_settimeout(unsigned int timeout) | |
138 | { | |
139 | unsigned int reg; | |
140 | unsigned int mr; | |
141 | ||
142 | /* Check if disabled */ | |
c1c30a29 | 143 | mr = wdt_read(AT91_WDT_MR); |
e6bb42e3 | 144 | if (mr & AT91_WDT_WDDIS) { |
27c766aa | 145 | pr_err("sorry, watchdog is disabled\n"); |
e6bb42e3 RC |
146 | return -EIO; |
147 | } | |
148 | ||
149 | /* | |
150 | * All counting occurs at SLOW_CLOCK / 128 = 256 Hz | |
151 | * | |
152 | * Since WDV is a 12-bit counter, the maximum period is | |
153 | * 4096 / 256 = 16 seconds. | |
154 | */ | |
155 | reg = AT91_WDT_WDRSTEN /* causes watchdog reset */ | |
156 | /* | AT91_WDT_WDRPROC causes processor reset only */ | |
157 | | AT91_WDT_WDDBGHLT /* disabled in debug mode */ | |
158 | | AT91_WDT_WDD /* restart at any time */ | |
159 | | (timeout & AT91_WDT_WDV); /* timer value */ | |
c1c30a29 | 160 | wdt_write(AT91_WDT_MR, reg); |
e6bb42e3 RC |
161 | |
162 | return 0; | |
163 | } | |
164 | ||
165 | static const struct watchdog_info at91_wdt_info = { | |
166 | .identity = DRV_NAME, | |
e73a7802 WVS |
167 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | |
168 | WDIOF_MAGICCLOSE, | |
e6bb42e3 RC |
169 | }; |
170 | ||
171 | /* | |
172 | * Handle commands from user-space. | |
173 | */ | |
174 | static long at91_wdt_ioctl(struct file *file, | |
175 | unsigned int cmd, unsigned long arg) | |
176 | { | |
177 | void __user *argp = (void __user *)arg; | |
178 | int __user *p = argp; | |
179 | int new_value; | |
180 | ||
181 | switch (cmd) { | |
182 | case WDIOC_GETSUPPORT: | |
183 | return copy_to_user(argp, &at91_wdt_info, | |
184 | sizeof(at91_wdt_info)) ? -EFAULT : 0; | |
185 | ||
186 | case WDIOC_GETSTATUS: | |
187 | case WDIOC_GETBOOTSTATUS: | |
188 | return put_user(0, p); | |
189 | ||
190 | case WDIOC_KEEPALIVE: | |
191 | at91wdt_private.next_heartbeat = jiffies + heartbeat * HZ; | |
192 | return 0; | |
193 | ||
194 | case WDIOC_SETTIMEOUT: | |
195 | if (get_user(new_value, p)) | |
196 | return -EFAULT; | |
197 | ||
198 | heartbeat = new_value; | |
199 | at91wdt_private.next_heartbeat = jiffies + heartbeat * HZ; | |
200 | ||
201 | return put_user(new_value, p); /* return current value */ | |
202 | ||
203 | case WDIOC_GETTIMEOUT: | |
204 | return put_user(heartbeat, p); | |
205 | } | |
206 | return -ENOTTY; | |
207 | } | |
208 | ||
209 | /* | |
210 | * Pat the watchdog whenever device is written to. | |
211 | */ | |
212 | static ssize_t at91_wdt_write(struct file *file, const char *data, size_t len, | |
143a2e54 | 213 | loff_t *ppos) |
e6bb42e3 RC |
214 | { |
215 | if (!len) | |
216 | return 0; | |
217 | ||
218 | /* Scan for magic character */ | |
219 | if (!nowayout) { | |
220 | size_t i; | |
221 | ||
222 | at91wdt_private.expect_close = 0; | |
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 | at91wdt_private.expect_close = 42; | |
230 | break; | |
231 | } | |
232 | } | |
233 | } | |
234 | ||
235 | at91wdt_private.next_heartbeat = jiffies + heartbeat * HZ; | |
236 | ||
237 | return len; | |
238 | } | |
239 | ||
240 | /* ......................................................................... */ | |
241 | ||
242 | static const struct file_operations at91wdt_fops = { | |
243 | .owner = THIS_MODULE, | |
244 | .llseek = no_llseek, | |
245 | .unlocked_ioctl = at91_wdt_ioctl, | |
246 | .open = at91_wdt_open, | |
247 | .release = at91_wdt_close, | |
248 | .write = at91_wdt_write, | |
249 | }; | |
250 | ||
251 | static struct miscdevice at91wdt_miscdev = { | |
252 | .minor = WATCHDOG_MINOR, | |
253 | .name = "watchdog", | |
254 | .fops = &at91wdt_fops, | |
255 | }; | |
256 | ||
257 | static int __init at91wdt_probe(struct platform_device *pdev) | |
258 | { | |
c1c30a29 | 259 | struct resource *r; |
e6bb42e3 RC |
260 | int res; |
261 | ||
262 | if (at91wdt_miscdev.parent) | |
263 | return -EBUSY; | |
264 | at91wdt_miscdev.parent = &pdev->dev; | |
265 | ||
c1c30a29 JCPV |
266 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
267 | if (!r) | |
268 | return -ENODEV; | |
269 | at91wdt_private.base = ioremap(r->start, resource_size(r)); | |
270 | if (!at91wdt_private.base) { | |
271 | dev_err(&pdev->dev, "failed to map registers, aborting.\n"); | |
272 | return -ENOMEM; | |
273 | } | |
274 | ||
e6bb42e3 RC |
275 | /* Set watchdog */ |
276 | res = at91_wdt_settimeout(ms_to_ticks(WDT_HW_TIMEOUT * 1000)); | |
277 | if (res) | |
278 | return res; | |
279 | ||
280 | res = misc_register(&at91wdt_miscdev); | |
281 | if (res) | |
282 | return res; | |
283 | ||
284 | at91wdt_private.next_heartbeat = jiffies + heartbeat * HZ; | |
285 | setup_timer(&at91wdt_private.timer, at91_ping, 0); | |
286 | mod_timer(&at91wdt_private.timer, jiffies + WDT_TIMEOUT); | |
287 | ||
27c766aa | 288 | pr_info("enabled (heartbeat=%d sec, nowayout=%d)\n", |
e6bb42e3 RC |
289 | heartbeat, nowayout); |
290 | ||
291 | return 0; | |
292 | } | |
293 | ||
294 | static int __exit at91wdt_remove(struct platform_device *pdev) | |
295 | { | |
296 | int res; | |
297 | ||
298 | res = misc_deregister(&at91wdt_miscdev); | |
299 | if (!res) | |
300 | at91wdt_miscdev.parent = NULL; | |
301 | ||
302 | return res; | |
303 | } | |
304 | ||
e6bb42e3 RC |
305 | static struct platform_driver at91wdt_driver = { |
306 | .remove = __exit_p(at91wdt_remove), | |
e6bb42e3 RC |
307 | .driver = { |
308 | .name = "at91_wdt", | |
309 | .owner = THIS_MODULE, | |
310 | }, | |
311 | }; | |
312 | ||
313 | static int __init at91sam_wdt_init(void) | |
314 | { | |
315 | return platform_driver_probe(&at91wdt_driver, at91wdt_probe); | |
316 | } | |
317 | ||
318 | static void __exit at91sam_wdt_exit(void) | |
319 | { | |
320 | platform_driver_unregister(&at91wdt_driver); | |
321 | } | |
322 | ||
323 | module_init(at91sam_wdt_init); | |
324 | module_exit(at91sam_wdt_exit); | |
325 | ||
326 | MODULE_AUTHOR("Renaud CERRATO <r.cerrato@til-technologies.fr>"); | |
327 | MODULE_DESCRIPTION("Watchdog driver for Atmel AT91SAM9x processors"); | |
328 | MODULE_LICENSE("GPL"); | |
329 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |