parport_pc: show the detection of a 2 serial port ITE8874 chip
[linux-2.6.git] / drivers / watchdog / nuc900_wdt.c
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");