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14#include <linux/device.h>
15#include <linux/resource.h>
16#include <linux/amba/bus.h>
17#include <linux/bitops.h>
18#include <linux/clk.h>
19#include <linux/fs.h>
20#include <linux/init.h>
21#include <linux/io.h>
22#include <linux/ioport.h>
23#include <linux/kernel.h>
24#include <linux/math64.h>
25#include <linux/miscdevice.h>
26#include <linux/module.h>
27#include <linux/moduleparam.h>
28#include <linux/pm.h>
29#include <linux/slab.h>
30#include <linux/spinlock.h>
31#include <linux/types.h>
32#include <linux/uaccess.h>
33#include <linux/watchdog.h>
34
35
36#define DEFAULT_TIMEOUT 60
37
38#define MODULE_NAME "sp805-wdt"
39
40
41#define WDTLOAD 0x000
42 #define LOAD_MIN 0x00000001
43 #define LOAD_MAX 0xFFFFFFFF
44#define WDTVALUE 0x004
45#define WDTCONTROL 0x008
46
47 #define INT_ENABLE (1 << 0)
48 #define RESET_ENABLE (1 << 1)
49#define WDTINTCLR 0x00C
50#define WDTRIS 0x010
51#define WDTMIS 0x014
52 #define INT_MASK (1 << 0)
53#define WDTLOCK 0xC00
54 #define UNLOCK 0x1ACCE551
55 #define LOCK 0x00000001
56
57
58
59
60
61
62
63
64
65
66
67struct sp805_wdt {
68 spinlock_t lock;
69 void __iomem *base;
70 struct clk *clk;
71 struct amba_device *adev;
72 unsigned long status;
73 #define WDT_BUSY 0
74 #define WDT_CAN_BE_CLOSED 1
75 unsigned int load_val;
76 unsigned int timeout;
77};
78
79
80static struct sp805_wdt *wdt;
81static bool nowayout = WATCHDOG_NOWAYOUT;
82
83
84static void wdt_setload(unsigned int timeout)
85{
86 u64 load, rate;
87
88 rate = clk_get_rate(wdt->clk);
89
90
91
92
93
94
95
96 load = div_u64(rate, 2) * timeout - 1;
97
98 load = (load > LOAD_MAX) ? LOAD_MAX : load;
99 load = (load < LOAD_MIN) ? LOAD_MIN : load;
100
101 spin_lock(&wdt->lock);
102 wdt->load_val = load;
103
104 wdt->timeout = div_u64((load + 1) * 2 + (rate / 2), rate);
105 spin_unlock(&wdt->lock);
106}
107
108
109static u32 wdt_timeleft(void)
110{
111 u64 load, rate;
112
113 rate = clk_get_rate(wdt->clk);
114
115 spin_lock(&wdt->lock);
116 load = readl_relaxed(wdt->base + WDTVALUE);
117
118
119 if (!(readl_relaxed(wdt->base + WDTRIS) & INT_MASK))
120 load += wdt->load_val + 1;
121 spin_unlock(&wdt->lock);
122
123 return div_u64(load, rate);
124}
125
126
127static void wdt_enable(void)
128{
129 spin_lock(&wdt->lock);
130
131 writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
132 writel_relaxed(wdt->load_val, wdt->base + WDTLOAD);
133 writel_relaxed(INT_MASK, wdt->base + WDTINTCLR);
134 writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base + WDTCONTROL);
135 writel_relaxed(LOCK, wdt->base + WDTLOCK);
136
137
138 readl_relaxed(wdt->base + WDTLOCK);
139 spin_unlock(&wdt->lock);
140}
141
142
143static void wdt_disable(void)
144{
145 spin_lock(&wdt->lock);
146
147 writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
148 writel_relaxed(0, wdt->base + WDTCONTROL);
149 writel_relaxed(LOCK, wdt->base + WDTLOCK);
150
151
152 readl_relaxed(wdt->base + WDTLOCK);
153 spin_unlock(&wdt->lock);
154}
155
156static ssize_t sp805_wdt_write(struct file *file, const char *data,
157 size_t len, loff_t *ppos)
158{
159 if (len) {
160 if (!nowayout) {
161 size_t i;
162
163 clear_bit(WDT_CAN_BE_CLOSED, &wdt->status);
164
165 for (i = 0; i != len; i++) {
166 char c;
167
168 if (get_user(c, data + i))
169 return -EFAULT;
170
171 if (c == 'V') {
172 set_bit(WDT_CAN_BE_CLOSED,
173 &wdt->status);
174 break;
175 }
176 }
177 }
178 wdt_enable();
179 }
180 return len;
181}
182
183static const struct watchdog_info ident = {
184 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
185 .identity = MODULE_NAME,
186};
187
188static long sp805_wdt_ioctl(struct file *file, unsigned int cmd,
189 unsigned long arg)
190{
191 int ret = -ENOTTY;
192 unsigned int timeout;
193
194 switch (cmd) {
195 case WDIOC_GETSUPPORT:
196 ret = copy_to_user((struct watchdog_info *)arg, &ident,
197 sizeof(ident)) ? -EFAULT : 0;
198 break;
199
200 case WDIOC_GETSTATUS:
201 ret = put_user(0, (int *)arg);
202 break;
203
204 case WDIOC_KEEPALIVE:
205 wdt_enable();
206 ret = 0;
207 break;
208
209 case WDIOC_SETTIMEOUT:
210 ret = get_user(timeout, (unsigned int *)arg);
211 if (ret)
212 break;
213
214 wdt_setload(timeout);
215
216 wdt_enable();
217
218
219 case WDIOC_GETTIMEOUT:
220 ret = put_user(wdt->timeout, (unsigned int *)arg);
221 break;
222 case WDIOC_GETTIMELEFT:
223 ret = put_user(wdt_timeleft(), (unsigned int *)arg);
224 break;
225 }
226 return ret;
227}
228
229static int sp805_wdt_open(struct inode *inode, struct file *file)
230{
231 int ret = 0;
232
233 if (test_and_set_bit(WDT_BUSY, &wdt->status))
234 return -EBUSY;
235
236 ret = clk_enable(wdt->clk);
237 if (ret) {
238 dev_err(&wdt->adev->dev, "clock enable fail");
239 goto err;
240 }
241
242 wdt_enable();
243
244
245 clear_bit(WDT_CAN_BE_CLOSED, &wdt->status);
246 return nonseekable_open(inode, file);
247
248err:
249 clear_bit(WDT_BUSY, &wdt->status);
250 return ret;
251}
252
253static int sp805_wdt_release(struct inode *inode, struct file *file)
254{
255 if (!test_bit(WDT_CAN_BE_CLOSED, &wdt->status)) {
256 clear_bit(WDT_BUSY, &wdt->status);
257 dev_warn(&wdt->adev->dev, "Device closed unexpectedly\n");
258 return 0;
259 }
260
261 wdt_disable();
262 clk_disable(wdt->clk);
263 clear_bit(WDT_BUSY, &wdt->status);
264
265 return 0;
266}
267
268static const struct file_operations sp805_wdt_fops = {
269 .owner = THIS_MODULE,
270 .llseek = no_llseek,
271 .write = sp805_wdt_write,
272 .unlocked_ioctl = sp805_wdt_ioctl,
273 .open = sp805_wdt_open,
274 .release = sp805_wdt_release,
275};
276
277static struct miscdevice sp805_wdt_miscdev = {
278 .minor = WATCHDOG_MINOR,
279 .name = "watchdog",
280 .fops = &sp805_wdt_fops,
281};
282
283static int __devinit
284sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
285{
286 int ret = 0;
287
288 if (!devm_request_mem_region(&adev->dev, adev->res.start,
289 resource_size(&adev->res), "sp805_wdt")) {
290 dev_warn(&adev->dev, "Failed to get memory region resource\n");
291 ret = -ENOENT;
292 goto err;
293 }
294
295 wdt = devm_kzalloc(&adev->dev, sizeof(*wdt), GFP_KERNEL);
296 if (!wdt) {
297 dev_warn(&adev->dev, "Kzalloc failed\n");
298 ret = -ENOMEM;
299 goto err;
300 }
301
302 wdt->base = devm_ioremap(&adev->dev, adev->res.start,
303 resource_size(&adev->res));
304 if (!wdt->base) {
305 ret = -ENOMEM;
306 dev_warn(&adev->dev, "ioremap fail\n");
307 goto err;
308 }
309
310 wdt->clk = clk_get(&adev->dev, NULL);
311 if (IS_ERR(wdt->clk)) {
312 dev_warn(&adev->dev, "Clock not found\n");
313 ret = PTR_ERR(wdt->clk);
314 goto err;
315 }
316
317 wdt->adev = adev;
318 spin_lock_init(&wdt->lock);
319 wdt_setload(DEFAULT_TIMEOUT);
320
321 ret = misc_register(&sp805_wdt_miscdev);
322 if (ret < 0) {
323 dev_warn(&adev->dev, "cannot register misc device\n");
324 goto err_misc_register;
325 }
326
327 dev_info(&adev->dev, "registration successful\n");
328 return 0;
329
330err_misc_register:
331 clk_put(wdt->clk);
332err:
333 dev_err(&adev->dev, "Probe Failed!!!\n");
334 return ret;
335}
336
337static int __devexit sp805_wdt_remove(struct amba_device *adev)
338{
339 misc_deregister(&sp805_wdt_miscdev);
340 clk_put(wdt->clk);
341
342 return 0;
343}
344
345#ifdef CONFIG_PM
346static int sp805_wdt_suspend(struct device *dev)
347{
348 if (test_bit(WDT_BUSY, &wdt->status)) {
349 wdt_disable();
350 clk_disable(wdt->clk);
351 }
352
353 return 0;
354}
355
356static int sp805_wdt_resume(struct device *dev)
357{
358 int ret = 0;
359
360 if (test_bit(WDT_BUSY, &wdt->status)) {
361 ret = clk_enable(wdt->clk);
362 if (ret) {
363 dev_err(dev, "clock enable fail");
364 return ret;
365 }
366 wdt_enable();
367 }
368
369 return ret;
370}
371#endif
372
373static SIMPLE_DEV_PM_OPS(sp805_wdt_dev_pm_ops, sp805_wdt_suspend,
374 sp805_wdt_resume);
375
376static struct amba_id sp805_wdt_ids[] = {
377 {
378 .id = 0x00141805,
379 .mask = 0x00ffffff,
380 },
381 { 0, 0 },
382};
383
384MODULE_DEVICE_TABLE(amba, sp805_wdt_ids);
385
386static struct amba_driver sp805_wdt_driver = {
387 .drv = {
388 .name = MODULE_NAME,
389 .pm = &sp805_wdt_dev_pm_ops,
390 },
391 .id_table = sp805_wdt_ids,
392 .probe = sp805_wdt_probe,
393 .remove = __devexit_p(sp805_wdt_remove),
394};
395
396module_amba_driver(sp805_wdt_driver);
397
398module_param(nowayout, bool, 0);
399MODULE_PARM_DESC(nowayout,
400 "Set to 1 to keep watchdog running after device release");
401
402MODULE_AUTHOR("Viresh Kumar <viresh.kumar@st.com>");
403MODULE_DESCRIPTION("ARM SP805 Watchdog Driver");
404MODULE_LICENSE("GPL");
405MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
406
