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1 | /* |
2 | * Copyright (c) 2009 Nuvoton technology corporation. |
3 | * |
4 | * Wan ZongShun <mcuos.com@gmail.com> |
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 as published by |
8 | * the Free Software Foundation;version 2 of the License. |
9 | * |
10 | */ |
11 | |
12 | #include <linux/bitops.h> |
13 | #include <linux/errno.h> |
14 | #include <linux/fs.h> |
15 | #include <linux/init.h> |
16 | #include <linux/io.h> |
17 | #include <linux/clk.h> |
18 | #include <linux/kernel.h> |
19 | #include <linux/miscdevice.h> |
20 | #include <linux/module.h> |
21 | #include <linux/moduleparam.h> |
22 | #include <linux/platform_device.h> |
23 | #include <linux/slab.h> |
24 | #include <linux/interrupt.h> |
25 | #include <linux/types.h> |
26 | #include <linux/watchdog.h> |
27 | #include <linux/uaccess.h> |
28 | |
29 | #define REG_WTCR 0x1c |
30 | #define WTCLK (0x01 << 10) |
31 | #define WTE (0x01 << 7) /*wdt enable*/ |
32 | #define WTIS (0x03 << 4) |
33 | #define WTIF (0x01 << 3) |
34 | #define WTRF (0x01 << 2) |
35 | #define WTRE (0x01 << 1) |
36 | #define WTR (0x01 << 0) |
37 | /* |
38 | * The watchdog time interval can be calculated via following formula: |
39 | * WTIS real time interval (formula) |
40 | * 0x00 ((2^ 14 ) * ((external crystal freq) / 256))seconds |
41 | * 0x01 ((2^ 16 ) * ((external crystal freq) / 256))seconds |
42 | * 0x02 ((2^ 18 ) * ((external crystal freq) / 256))seconds |
43 | * 0x03 ((2^ 20 ) * ((external crystal freq) / 256))seconds |
44 | * |
45 | * The external crystal freq is 15Mhz in the nuc900 evaluation board. |
46 | * So 0x00 = +-0.28 seconds, 0x01 = +-1.12 seconds, 0x02 = +-4.48 seconds, |
47 | * 0x03 = +- 16.92 seconds.. |
48 | */ |
49 | #define WDT_HW_TIMEOUT 0x02 |
50 | #define WDT_TIMEOUT (HZ/2) |
51 | #define WDT_HEARTBEAT 15 |
52 | |
53 | static int heartbeat = WDT_HEARTBEAT; |
54 | module_param(heartbeat, int, 0); |
55 | MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. " |
56 | "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")"); |
57 | |
58 | static int nowayout = WATCHDOG_NOWAYOUT; |
59 | module_param(nowayout, int, 0); |
60 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " |
61 | "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
62 | |
63 | struct nuc900_wdt { |
64 | struct resource *res; |
65 | struct clk *wdt_clock; |
66 | struct platform_device *pdev; |
67 | void __iomem *wdt_base; |
68 | char expect_close; |
69 | struct timer_list timer; |
70 | spinlock_t wdt_lock; |
71 | unsigned long next_heartbeat; |
72 | }; |
73 | |
74 | static unsigned long nuc900wdt_busy; |
75 | struct nuc900_wdt *nuc900_wdt; |
76 | |
77 | static inline void nuc900_wdt_keepalive(void) |
78 | { |
79 | unsigned int val; |
80 | |
81 | spin_lock(&nuc900_wdt->wdt_lock); |
82 | |
83 | val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); |
84 | val |= (WTR | WTIF); |
85 | __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); |
86 | |
87 | spin_unlock(&nuc900_wdt->wdt_lock); |
88 | } |
89 | |
90 | static inline void nuc900_wdt_start(void) |
91 | { |
92 | unsigned int val; |
93 | |
94 | spin_lock(&nuc900_wdt->wdt_lock); |
95 | |
96 | val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); |
97 | val |= (WTRE | WTE | WTR | WTCLK | WTIF); |
98 | val &= ~WTIS; |
99 | val |= (WDT_HW_TIMEOUT << 0x04); |
100 | __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); |
101 | |
102 | spin_unlock(&nuc900_wdt->wdt_lock); |
103 | |
104 | nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ; |
105 | mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT); |
106 | } |
107 | |
108 | static inline void nuc900_wdt_stop(void) |
109 | { |
110 | unsigned int val; |
111 | |
112 | del_timer(&nuc900_wdt->timer); |
113 | |
114 | spin_lock(&nuc900_wdt->wdt_lock); |
115 | |
116 | val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); |
117 | val &= ~WTE; |
118 | __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); |
119 | |
120 | spin_unlock(&nuc900_wdt->wdt_lock); |
121 | } |
122 | |
123 | static inline void nuc900_wdt_ping(void) |
124 | { |
125 | nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ; |
126 | } |
127 | |
128 | static int nuc900_wdt_open(struct inode *inode, struct file *file) |
129 | { |
130 | |
131 | if (test_and_set_bit(0, &nuc900wdt_busy)) |
132 | return -EBUSY; |
133 | |
134 | nuc900_wdt_start(); |
135 | |
136 | return nonseekable_open(inode, file); |
137 | } |
138 | |
139 | static int nuc900_wdt_close(struct inode *inode, struct file *file) |
140 | { |
141 | if (nuc900_wdt->expect_close == 42) |
142 | nuc900_wdt_stop(); |
143 | else { |
144 | dev_crit(&nuc900_wdt->pdev->dev, |
145 | "Unexpected close, not stopping watchdog!\n"); |
146 | nuc900_wdt_ping(); |
147 | } |
148 | |
149 | nuc900_wdt->expect_close = 0; |
150 | clear_bit(0, &nuc900wdt_busy); |
151 | return 0; |
152 | } |
153 | |
154 | static const struct watchdog_info nuc900_wdt_info = { |
155 | .identity = "nuc900 watchdog", |
156 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | |
157 | WDIOF_MAGICCLOSE, |
158 | }; |
159 | |
160 | static long nuc900_wdt_ioctl(struct file *file, |
161 | unsigned int cmd, unsigned long arg) |
162 | { |
163 | void __user *argp = (void __user *)arg; |
164 | int __user *p = argp; |
165 | int new_value; |
166 | |
167 | switch (cmd) { |
168 | case WDIOC_GETSUPPORT: |
169 | return copy_to_user(argp, &nuc900_wdt_info, |
170 | sizeof(nuc900_wdt_info)) ? -EFAULT : 0; |
171 | case WDIOC_GETSTATUS: |
172 | case WDIOC_GETBOOTSTATUS: |
173 | return put_user(0, p); |
174 | |
175 | case WDIOC_KEEPALIVE: |
176 | nuc900_wdt_ping(); |
177 | return 0; |
178 | |
179 | case WDIOC_SETTIMEOUT: |
180 | if (get_user(new_value, p)) |
181 | return -EFAULT; |
182 | |
183 | heartbeat = new_value; |
184 | nuc900_wdt_ping(); |
185 | |
186 | return put_user(new_value, p); |
187 | case WDIOC_GETTIMEOUT: |
188 | return put_user(heartbeat, p); |
189 | default: |
190 | return -ENOTTY; |
191 | } |
192 | } |
193 | |
194 | static ssize_t nuc900_wdt_write(struct file *file, const char __user *data, |
195 | size_t len, loff_t *ppos) |
196 | { |
197 | if (!len) |
198 | return 0; |
199 | |
200 | /* Scan for magic character */ |
201 | if (!nowayout) { |
202 | size_t i; |
203 | |
204 | nuc900_wdt->expect_close = 0; |
205 | |
206 | for (i = 0; i < len; i++) { |
207 | char c; |
208 | if (get_user(c, data + i)) |
209 | return -EFAULT; |
210 | if (c == 'V') { |
211 | nuc900_wdt->expect_close = 42; |
212 | break; |
213 | } |
214 | } |
215 | } |
216 | |
217 | nuc900_wdt_ping(); |
218 | return len; |
219 | } |
220 | |
221 | static void nuc900_wdt_timer_ping(unsigned long data) |
222 | { |
223 | if (time_before(jiffies, nuc900_wdt->next_heartbeat)) { |
224 | nuc900_wdt_keepalive(); |
225 | mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT); |
226 | } else |
227 | dev_warn(&nuc900_wdt->pdev->dev, "Will reset the machine !\n"); |
228 | } |
229 | |
230 | static const struct file_operations nuc900wdt_fops = { |
231 | .owner = THIS_MODULE, |
232 | .llseek = no_llseek, |
233 | .unlocked_ioctl = nuc900_wdt_ioctl, |
234 | .open = nuc900_wdt_open, |
235 | .release = nuc900_wdt_close, |
236 | .write = nuc900_wdt_write, |
237 | }; |
238 | |
239 | static struct miscdevice nuc900wdt_miscdev = { |
240 | .minor = WATCHDOG_MINOR, |
241 | .name = "watchdog", |
242 | .fops = &nuc900wdt_fops, |
243 | }; |
244 | |
245 | static int __devinit nuc900wdt_probe(struct platform_device *pdev) |
246 | { |
247 | int ret = 0; |
248 | |
249 | nuc900_wdt = kzalloc(sizeof(struct nuc900_wdt), GFP_KERNEL); |
250 | if (!nuc900_wdt) |
251 | return -ENOMEM; |
252 | |
253 | nuc900_wdt->pdev = pdev; |
254 | |
255 | spin_lock_init(&nuc900_wdt->wdt_lock); |
256 | |
257 | nuc900_wdt->res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
258 | if (nuc900_wdt->res == NULL) { |
259 | dev_err(&pdev->dev, "no memory resource specified\n"); |
260 | ret = -ENOENT; |
261 | goto err_get; |
262 | } |
263 | |
264 | if (!request_mem_region(nuc900_wdt->res->start, |
265 | resource_size(nuc900_wdt->res), pdev->name)) { |
266 | dev_err(&pdev->dev, "failed to get memory region\n"); |
267 | ret = -ENOENT; |
268 | goto err_get; |
269 | } |
270 | |
271 | nuc900_wdt->wdt_base = ioremap(nuc900_wdt->res->start, |
272 | resource_size(nuc900_wdt->res)); |
273 | if (nuc900_wdt->wdt_base == NULL) { |
274 | dev_err(&pdev->dev, "failed to ioremap() region\n"); |
275 | ret = -EINVAL; |
276 | goto err_req; |
277 | } |
278 | |
279 | nuc900_wdt->wdt_clock = clk_get(&pdev->dev, NULL); |
280 | if (IS_ERR(nuc900_wdt->wdt_clock)) { |
281 | dev_err(&pdev->dev, "failed to find watchdog clock source\n"); |
282 | ret = PTR_ERR(nuc900_wdt->wdt_clock); |
283 | goto err_map; |
284 | } |
285 | |
286 | clk_enable(nuc900_wdt->wdt_clock); |
287 | |
288 | setup_timer(&nuc900_wdt->timer, nuc900_wdt_timer_ping, 0); |
289 | |
290 | if (misc_register(&nuc900wdt_miscdev)) { |
291 | dev_err(&pdev->dev, "err register miscdev on minor=%d (%d)\n", |
292 | WATCHDOG_MINOR, ret); |
293 | goto err_clk; |
294 | } |
295 | |
296 | return 0; |
297 | |
298 | err_clk: |
299 | clk_disable(nuc900_wdt->wdt_clock); |
300 | clk_put(nuc900_wdt->wdt_clock); |
301 | err_map: |
302 | iounmap(nuc900_wdt->wdt_base); |
303 | err_req: |
304 | release_mem_region(nuc900_wdt->res->start, |
305 | resource_size(nuc900_wdt->res)); |
306 | err_get: |
307 | kfree(nuc900_wdt); |
308 | return ret; |
309 | } |
310 | |
311 | static int __devexit nuc900wdt_remove(struct platform_device *pdev) |
312 | { |
313 | misc_deregister(&nuc900wdt_miscdev); |
314 | |
315 | clk_disable(nuc900_wdt->wdt_clock); |
316 | clk_put(nuc900_wdt->wdt_clock); |
317 | |
318 | iounmap(nuc900_wdt->wdt_base); |
319 | |
320 | release_mem_region(nuc900_wdt->res->start, |
321 | resource_size(nuc900_wdt->res)); |
322 | |
323 | kfree(nuc900_wdt); |
324 | |
325 | return 0; |
326 | } |
327 | |
328 | static struct platform_driver nuc900wdt_driver = { |
329 | .probe = nuc900wdt_probe, |
330 | .remove = __devexit_p(nuc900wdt_remove), |
331 | .driver = { |
332 | .name = "nuc900-wdt", |
333 | .owner = THIS_MODULE, |
334 | }, |
335 | }; |
336 | |
337 | static int __init nuc900_wdt_init(void) |
338 | { |
339 | return platform_driver_register(&nuc900wdt_driver); |
340 | } |
341 | |
342 | static void __exit nuc900_wdt_exit(void) |
343 | { |
344 | platform_driver_unregister(&nuc900wdt_driver); |
345 | } |
346 | |
347 | module_init(nuc900_wdt_init); |
348 | module_exit(nuc900_wdt_exit); |
349 | |
350 | MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>"); |
351 | MODULE_DESCRIPTION("Watchdog driver for NUC900"); |
352 | MODULE_LICENSE("GPL"); |
353 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
354 | MODULE_ALIAS("platform:nuc900-wdt"); |
355 |
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