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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)
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
39
40
41
42
43
44
45
46
47
48
49#define WDT_HW_TIMEOUT 0x02
50#define WDT_TIMEOUT (HZ/2)
51#define WDT_HEARTBEAT 15
52
53static int heartbeat = WDT_HEARTBEAT;
54module_param(heartbeat, int, 0);
55MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
56 "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
57
58static bool nowayout = WATCHDOG_NOWAYOUT;
59module_param(nowayout, bool, 0);
60MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
61 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
62
63struct 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
74static unsigned long nuc900wdt_busy;
75static struct nuc900_wdt *nuc900_wdt;
76
77static 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
90static 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
108static 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
123static inline void nuc900_wdt_ping(void)
124{
125 nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ;
126}
127
128static 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
139static 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
154static const struct watchdog_info nuc900_wdt_info = {
155 .identity = "nuc900 watchdog",
156 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
157 WDIOF_MAGICCLOSE,
158};
159
160static 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
194static 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
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
221static 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
230static 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
239static struct miscdevice nuc900wdt_miscdev = {
240 .minor = WATCHDOG_MINOR,
241 .name = "watchdog",
242 .fops = &nuc900wdt_fops,
243};
244
245static 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 ret = misc_register(&nuc900wdt_miscdev);
291 if (ret) {
292 dev_err(&pdev->dev, "err register miscdev on minor=%d (%d)\n",
293 WATCHDOG_MINOR, ret);
294 goto err_clk;
295 }
296
297 return 0;
298
299err_clk:
300 clk_disable(nuc900_wdt->wdt_clock);
301 clk_put(nuc900_wdt->wdt_clock);
302err_map:
303 iounmap(nuc900_wdt->wdt_base);
304err_req:
305 release_mem_region(nuc900_wdt->res->start,
306 resource_size(nuc900_wdt->res));
307err_get:
308 kfree(nuc900_wdt);
309 return ret;
310}
311
312static int __devexit nuc900wdt_remove(struct platform_device *pdev)
313{
314 misc_deregister(&nuc900wdt_miscdev);
315
316 clk_disable(nuc900_wdt->wdt_clock);
317 clk_put(nuc900_wdt->wdt_clock);
318
319 iounmap(nuc900_wdt->wdt_base);
320
321 release_mem_region(nuc900_wdt->res->start,
322 resource_size(nuc900_wdt->res));
323
324 kfree(nuc900_wdt);
325
326 return 0;
327}
328
329static struct platform_driver nuc900wdt_driver = {
330 .probe = nuc900wdt_probe,
331 .remove = __devexit_p(nuc900wdt_remove),
332 .driver = {
333 .name = "nuc900-wdt",
334 .owner = THIS_MODULE,
335 },
336};
337
338module_platform_driver(nuc900wdt_driver);
339
340MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
341MODULE_DESCRIPTION("Watchdog driver for NUC900");
342MODULE_LICENSE("GPL");
343MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
344MODULE_ALIAS("platform:nuc900-wdt");
345
