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1 | /* |
2 | * Broadcom BCM63xx SoC watchdog driver | |
3 | * | |
4 | * Copyright (C) 2007, Miguel Gaio <miguel.gaio@efixo.com> | |
5 | * Copyright (C) 2008, Florian Fainelli <florian@openwrt.org> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License | |
9 | * as published by the Free Software Foundation; either version | |
10 | * 2 of the License, or (at your option) any later version. | |
11 | */ | |
12 | ||
13 | #include <linux/bitops.h> | |
14 | #include <linux/errno.h> | |
15 | #include <linux/fs.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/miscdevice.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/moduleparam.h> | |
21 | #include <linux/reboot.h> | |
22 | #include <linux/types.h> | |
23 | #include <linux/uaccess.h> | |
24 | #include <linux/watchdog.h> | |
25 | #include <linux/timer.h> | |
26 | #include <linux/jiffies.h> | |
27 | #include <linux/interrupt.h> | |
28 | #include <linux/ptrace.h> | |
29 | #include <linux/resource.h> | |
30 | #include <linux/platform_device.h> | |
31 | ||
32 | #include <bcm63xx_cpu.h> | |
33 | #include <bcm63xx_io.h> | |
34 | #include <bcm63xx_regs.h> | |
35 | #include <bcm63xx_timer.h> | |
36 | ||
37 | #define PFX KBUILD_MODNAME | |
38 | ||
39 | #define WDT_HZ 50000000 /* Fclk */ | |
40 | #define WDT_DEFAULT_TIME 30 /* seconds */ | |
41 | #define WDT_MAX_TIME 256 /* seconds */ | |
42 | ||
43 | static struct { | |
44 | void __iomem *regs; | |
45 | struct timer_list timer; | |
46 | int default_ticks; | |
47 | unsigned long inuse; | |
48 | atomic_t ticks; | |
49 | } bcm63xx_wdt_device; | |
50 | ||
51 | static int expect_close; | |
52 | ||
53 | static int wdt_time = WDT_DEFAULT_TIME; | |
54 | static int nowayout = WATCHDOG_NOWAYOUT; | |
55 | module_param(nowayout, int, 0); | |
56 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" | |
57 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
58 | ||
59 | /* HW functions */ | |
60 | static void bcm63xx_wdt_hw_start(void) | |
61 | { | |
62 | bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG); | |
63 | bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG); | |
64 | bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG); | |
65 | } | |
66 | ||
67 | static void bcm63xx_wdt_hw_stop(void) | |
68 | { | |
69 | bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG); | |
70 | bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG); | |
71 | } | |
72 | ||
73 | static void bcm63xx_wdt_isr(void *data) | |
74 | { | |
75 | struct pt_regs *regs = get_irq_regs(); | |
76 | ||
77 | die(PFX " fire", regs); | |
78 | } | |
79 | ||
80 | static void bcm63xx_timer_tick(unsigned long unused) | |
81 | { | |
82 | if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) { | |
83 | bcm63xx_wdt_hw_start(); | |
84 | mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ); | |
85 | } else | |
86 | printk(KERN_CRIT PFX ": watchdog will restart system\n"); | |
87 | } | |
88 | ||
89 | static void bcm63xx_wdt_pet(void) | |
90 | { | |
91 | atomic_set(&bcm63xx_wdt_device.ticks, wdt_time); | |
92 | } | |
93 | ||
94 | static void bcm63xx_wdt_start(void) | |
95 | { | |
96 | bcm63xx_wdt_pet(); | |
97 | bcm63xx_timer_tick(0); | |
98 | } | |
99 | ||
100 | static void bcm63xx_wdt_pause(void) | |
101 | { | |
102 | del_timer_sync(&bcm63xx_wdt_device.timer); | |
103 | bcm63xx_wdt_hw_stop(); | |
104 | } | |
105 | ||
106 | static int bcm63xx_wdt_settimeout(int new_time) | |
107 | { | |
108 | if ((new_time <= 0) || (new_time > WDT_MAX_TIME)) | |
109 | return -EINVAL; | |
110 | ||
111 | wdt_time = new_time; | |
112 | ||
113 | return 0; | |
114 | } | |
115 | ||
116 | static int bcm63xx_wdt_open(struct inode *inode, struct file *file) | |
117 | { | |
118 | if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse)) | |
119 | return -EBUSY; | |
120 | ||
121 | bcm63xx_wdt_start(); | |
122 | return nonseekable_open(inode, file); | |
123 | } | |
124 | ||
125 | static int bcm63xx_wdt_release(struct inode *inode, struct file *file) | |
126 | { | |
127 | if (expect_close == 42) | |
128 | bcm63xx_wdt_pause(); | |
129 | else { | |
130 | printk(KERN_CRIT PFX | |
131 | ": Unexpected close, not stopping watchdog!\n"); | |
132 | bcm63xx_wdt_start(); | |
133 | } | |
134 | clear_bit(0, &bcm63xx_wdt_device.inuse); | |
135 | expect_close = 0; | |
136 | return 0; | |
137 | } | |
138 | ||
139 | static ssize_t bcm63xx_wdt_write(struct file *file, const char *data, | |
140 | size_t len, loff_t *ppos) | |
141 | { | |
142 | if (len) { | |
143 | if (!nowayout) { | |
144 | size_t i; | |
145 | ||
146 | /* In case it was set long ago */ | |
147 | expect_close = 0; | |
148 | ||
149 | for (i = 0; i != len; i++) { | |
150 | char c; | |
151 | if (get_user(c, data + i)) | |
152 | return -EFAULT; | |
153 | if (c == 'V') | |
154 | expect_close = 42; | |
155 | } | |
156 | } | |
157 | bcm63xx_wdt_pet(); | |
158 | } | |
159 | return len; | |
160 | } | |
161 | ||
162 | static struct watchdog_info bcm63xx_wdt_info = { | |
163 | .identity = PFX, | |
164 | .options = WDIOF_SETTIMEOUT | | |
165 | WDIOF_KEEPALIVEPING | | |
166 | WDIOF_MAGICCLOSE, | |
167 | }; | |
168 | ||
169 | ||
170 | static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd, | |
171 | unsigned long arg) | |
172 | { | |
173 | void __user *argp = (void __user *)arg; | |
174 | int __user *p = argp; | |
175 | int new_value, retval = -EINVAL; | |
176 | ||
177 | switch (cmd) { | |
178 | case WDIOC_GETSUPPORT: | |
179 | return copy_to_user(argp, &bcm63xx_wdt_info, | |
180 | sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0; | |
181 | ||
182 | case WDIOC_GETSTATUS: | |
183 | case WDIOC_GETBOOTSTATUS: | |
184 | return put_user(0, p); | |
185 | ||
186 | case WDIOC_SETOPTIONS: | |
187 | if (get_user(new_value, p)) | |
188 | return -EFAULT; | |
189 | ||
190 | if (new_value & WDIOS_DISABLECARD) { | |
191 | bcm63xx_wdt_pause(); | |
192 | retval = 0; | |
193 | } | |
194 | if (new_value & WDIOS_ENABLECARD) { | |
195 | bcm63xx_wdt_start(); | |
196 | retval = 0; | |
197 | } | |
198 | ||
199 | return retval; | |
200 | ||
201 | case WDIOC_KEEPALIVE: | |
202 | bcm63xx_wdt_pet(); | |
203 | return 0; | |
204 | ||
205 | case WDIOC_SETTIMEOUT: | |
206 | if (get_user(new_value, p)) | |
207 | return -EFAULT; | |
208 | ||
209 | if (bcm63xx_wdt_settimeout(new_value)) | |
210 | return -EINVAL; | |
211 | ||
212 | bcm63xx_wdt_pet(); | |
213 | ||
214 | case WDIOC_GETTIMEOUT: | |
215 | return put_user(wdt_time, p); | |
216 | ||
217 | default: | |
218 | return -ENOTTY; | |
219 | ||
220 | } | |
221 | } | |
222 | ||
223 | static int bcm63xx_wdt_notify_sys(struct notifier_block *this, | |
224 | unsigned long code, void *unused) | |
225 | { | |
226 | if (code == SYS_DOWN || code == SYS_HALT) | |
227 | bcm63xx_wdt_pause(); | |
228 | return NOTIFY_DONE; | |
229 | } | |
230 | ||
231 | static const struct file_operations bcm63xx_wdt_fops = { | |
232 | .owner = THIS_MODULE, | |
233 | .llseek = no_llseek, | |
234 | .write = bcm63xx_wdt_write, | |
235 | .unlocked_ioctl = bcm63xx_wdt_ioctl, | |
236 | .open = bcm63xx_wdt_open, | |
237 | .release = bcm63xx_wdt_release, | |
238 | }; | |
239 | ||
240 | static struct miscdevice bcm63xx_wdt_miscdev = { | |
241 | .minor = WATCHDOG_MINOR, | |
242 | .name = "watchdog", | |
243 | .fops = &bcm63xx_wdt_fops, | |
244 | }; | |
245 | ||
246 | static struct notifier_block bcm63xx_wdt_notifier = { | |
247 | .notifier_call = bcm63xx_wdt_notify_sys, | |
248 | }; | |
249 | ||
250 | ||
251 | static int bcm63xx_wdt_probe(struct platform_device *pdev) | |
252 | { | |
253 | int ret; | |
254 | struct resource *r; | |
255 | ||
256 | setup_timer(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0L); | |
257 | ||
258 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
259 | if (!r) { | |
260 | dev_err(&pdev->dev, "failed to get resources\n"); | |
261 | return -ENODEV; | |
262 | } | |
263 | ||
264 | bcm63xx_wdt_device.regs = ioremap_nocache(r->start, r->end - r->start); | |
265 | if (!bcm63xx_wdt_device.regs) { | |
266 | dev_err(&pdev->dev, "failed to remap I/O resources\n"); | |
267 | return -ENXIO; | |
268 | } | |
269 | ||
270 | ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL); | |
271 | if (ret < 0) { | |
272 | dev_err(&pdev->dev, "failed to register wdt timer isr\n"); | |
273 | goto unmap; | |
274 | } | |
275 | ||
276 | if (bcm63xx_wdt_settimeout(wdt_time)) { | |
277 | bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME); | |
278 | dev_info(&pdev->dev, | |
279 | ": wdt_time value must be 1 <= wdt_time <= 256, using %d\n", | |
280 | wdt_time); | |
281 | } | |
282 | ||
283 | ret = register_reboot_notifier(&bcm63xx_wdt_notifier); | |
284 | if (ret) { | |
285 | dev_err(&pdev->dev, "failed to register reboot_notifier\n"); | |
286 | goto unregister_timer; | |
287 | } | |
288 | ||
289 | ret = misc_register(&bcm63xx_wdt_miscdev); | |
290 | if (ret < 0) { | |
291 | dev_err(&pdev->dev, "failed to register watchdog device\n"); | |
292 | goto unregister_reboot_notifier; | |
293 | } | |
294 | ||
295 | dev_info(&pdev->dev, " started, timer margin: %d sec\n", | |
296 | WDT_DEFAULT_TIME); | |
297 | ||
298 | return 0; | |
299 | ||
300 | unregister_reboot_notifier: | |
301 | unregister_reboot_notifier(&bcm63xx_wdt_notifier); | |
302 | unregister_timer: | |
303 | bcm63xx_timer_unregister(TIMER_WDT_ID); | |
304 | unmap: | |
305 | iounmap(bcm63xx_wdt_device.regs); | |
306 | return ret; | |
307 | } | |
308 | ||
309 | static int bcm63xx_wdt_remove(struct platform_device *pdev) | |
310 | { | |
311 | if (!nowayout) | |
312 | bcm63xx_wdt_pause(); | |
313 | ||
314 | misc_deregister(&bcm63xx_wdt_miscdev); | |
315 | ||
316 | iounmap(bcm63xx_wdt_device.regs); | |
317 | ||
318 | unregister_reboot_notifier(&bcm63xx_wdt_notifier); | |
319 | bcm63xx_timer_unregister(TIMER_WDT_ID); | |
320 | ||
321 | return 0; | |
322 | } | |
323 | ||
324 | static struct platform_driver bcm63xx_wdt = { | |
325 | .probe = bcm63xx_wdt_probe, | |
326 | .remove = bcm63xx_wdt_remove, | |
327 | .driver = { | |
328 | .name = "bcm63xx-wdt", | |
329 | } | |
330 | }; | |
331 | ||
332 | static int __init bcm63xx_wdt_init(void) | |
333 | { | |
334 | return platform_driver_register(&bcm63xx_wdt); | |
335 | } | |
336 | ||
337 | static void __exit bcm63xx_wdt_exit(void) | |
338 | { | |
339 | platform_driver_unregister(&bcm63xx_wdt); | |
340 | } | |
341 | ||
342 | module_init(bcm63xx_wdt_init); | |
343 | module_exit(bcm63xx_wdt_exit); | |
344 | ||
345 | MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>"); | |
346 | MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>"); | |
347 | MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog"); | |
348 | MODULE_LICENSE("GPL"); | |
349 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
350 | MODULE_ALIAS("platform:bcm63xx-wdt"); |