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18#include <linux/fs.h>
19#include <linux/init.h>
20#include <linux/kernel.h>
21#include <linux/miscdevice.h>
22#include <linux/module.h>
23#include <linux/watchdog.h>
24#include <linux/platform_device.h>
25#include <linux/mv643xx.h>
26#include <linux/uaccess.h>
27#include <linux/io.h>
28
29#define MV64x60_WDT_WDC_OFFSET 0
30
31
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40
41
42#define MV64x60_WDC_ENABLE_SHIFT 24
43#define MV64x60_WDC_SERVICE_SHIFT 26
44#define MV64x60_WDC_ENABLED_SHIFT 31
45
46#define MV64x60_WDC_ENABLED_TRUE 1
47#define MV64x60_WDC_ENABLED_FALSE 0
48
49
50#define MV64x60_WDOG_FLAG_OPENED 0
51
52static unsigned long wdt_flags;
53static int wdt_status;
54static void __iomem *mv64x60_wdt_regs;
55static int mv64x60_wdt_timeout;
56static int mv64x60_wdt_count;
57static unsigned int bus_clk;
58static char expect_close;
59static DEFINE_SPINLOCK(mv64x60_wdt_spinlock);
60
61static int nowayout = WATCHDOG_NOWAYOUT;
62module_param(nowayout, int, 0);
63MODULE_PARM_DESC(nowayout,
64 "Watchdog cannot be stopped once started (default="
65 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
66
67static int mv64x60_wdt_toggle_wdc(int enabled_predicate, int field_shift)
68{
69 u32 data;
70 u32 enabled;
71 int ret = 0;
72
73 spin_lock(&mv64x60_wdt_spinlock);
74 data = readl(mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
75 enabled = (data >> MV64x60_WDC_ENABLED_SHIFT) & 1;
76
77
78 if ((enabled ^ enabled_predicate) == 0) {
79
80 data = (1 << field_shift) | mv64x60_wdt_count;
81 writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
82
83 data = (2 << field_shift) | mv64x60_wdt_count;
84 writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
85 ret = 1;
86 }
87 spin_unlock(&mv64x60_wdt_spinlock);
88
89 return ret;
90}
91
92static void mv64x60_wdt_service(void)
93{
94 mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
95 MV64x60_WDC_SERVICE_SHIFT);
96}
97
98static void mv64x60_wdt_handler_enable(void)
99{
100 if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_FALSE,
101 MV64x60_WDC_ENABLE_SHIFT)) {
102 mv64x60_wdt_service();
103 printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
104 }
105}
106
107static void mv64x60_wdt_handler_disable(void)
108{
109 if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
110 MV64x60_WDC_ENABLE_SHIFT))
111 printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");
112}
113
114static void mv64x60_wdt_set_timeout(unsigned int timeout)
115{
116
117 if (timeout > 0xFFFFFFFF / bus_clk)
118 timeout = 0xFFFFFFFF / bus_clk;
119
120 mv64x60_wdt_count = timeout * bus_clk >> 8;
121 mv64x60_wdt_timeout = timeout;
122}
123
124static int mv64x60_wdt_open(struct inode *inode, struct file *file)
125{
126 if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
127 return -EBUSY;
128
129 if (nowayout)
130 __module_get(THIS_MODULE);
131
132 mv64x60_wdt_handler_enable();
133
134 return nonseekable_open(inode, file);
135}
136
137static int mv64x60_wdt_release(struct inode *inode, struct file *file)
138{
139 if (expect_close == 42)
140 mv64x60_wdt_handler_disable();
141 else {
142 printk(KERN_CRIT
143 "mv64x60_wdt: unexpected close, not stopping timer!\n");
144 mv64x60_wdt_service();
145 }
146 expect_close = 0;
147
148 clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);
149
150 return 0;
151}
152
153static ssize_t mv64x60_wdt_write(struct file *file, const char __user *data,
154 size_t len, loff_t *ppos)
155{
156 if (len) {
157 if (!nowayout) {
158 size_t i;
159
160 expect_close = 0;
161
162 for (i = 0; i != len; i++) {
163 char c;
164 if (get_user(c, data + i))
165 return -EFAULT;
166 if (c == 'V')
167 expect_close = 42;
168 }
169 }
170 mv64x60_wdt_service();
171 }
172
173 return len;
174}
175
176static long mv64x60_wdt_ioctl(struct file *file,
177 unsigned int cmd, unsigned long arg)
178{
179 int timeout;
180 int options;
181 void __user *argp = (void __user *)arg;
182 static struct watchdog_info info = {
183 .options = WDIOF_SETTIMEOUT |
184 WDIOF_MAGICCLOSE |
185 WDIOF_KEEPALIVEPING,
186 .firmware_version = 0,
187 .identity = "MV64x60 watchdog",
188 };
189
190 switch (cmd) {
191 case WDIOC_GETSUPPORT:
192 if (copy_to_user(argp, &info, sizeof(info)))
193 return -EFAULT;
194 break;
195
196 case WDIOC_GETSTATUS:
197 case WDIOC_GETBOOTSTATUS:
198 if (put_user(wdt_status, (int __user *)argp))
199 return -EFAULT;
200 wdt_status &= ~WDIOF_KEEPALIVEPING;
201 break;
202
203 case WDIOC_GETTEMP:
204 return -EOPNOTSUPP;
205
206 case WDIOC_SETOPTIONS:
207 if (get_user(options, (int __user *)argp))
208 return -EFAULT;
209
210 if (options & WDIOS_DISABLECARD)
211 mv64x60_wdt_handler_disable();
212
213 if (options & WDIOS_ENABLECARD)
214 mv64x60_wdt_handler_enable();
215 break;
216
217 case WDIOC_KEEPALIVE:
218 mv64x60_wdt_service();
219 wdt_status |= WDIOF_KEEPALIVEPING;
220 break;
221
222 case WDIOC_SETTIMEOUT:
223 if (get_user(timeout, (int __user *)argp))
224 return -EFAULT;
225 mv64x60_wdt_set_timeout(timeout);
226
227
228 case WDIOC_GETTIMEOUT:
229 if (put_user(mv64x60_wdt_timeout, (int __user *)argp))
230 return -EFAULT;
231 break;
232
233 default:
234 return -ENOTTY;
235 }
236
237 return 0;
238}
239
240static const struct file_operations mv64x60_wdt_fops = {
241 .owner = THIS_MODULE,
242 .llseek = no_llseek,
243 .write = mv64x60_wdt_write,
244 .unlocked_ioctl = mv64x60_wdt_ioctl,
245 .open = mv64x60_wdt_open,
246 .release = mv64x60_wdt_release,
247};
248
249static struct miscdevice mv64x60_wdt_miscdev = {
250 .minor = WATCHDOG_MINOR,
251 .name = "watchdog",
252 .fops = &mv64x60_wdt_fops,
253};
254
255static int __devinit mv64x60_wdt_probe(struct platform_device *dev)
256{
257 struct mv64x60_wdt_pdata *pdata = dev->dev.platform_data;
258 struct resource *r;
259 int timeout = 10;
260
261 bus_clk = 133;
262 if (pdata) {
263 timeout = pdata->timeout;
264 bus_clk = pdata->bus_clk;
265 }
266
267
268
269
270
271 bus_clk++;
272 bus_clk *= 1000000;
273
274 r = platform_get_resource(dev, IORESOURCE_MEM, 0);
275 if (!r)
276 return -ENODEV;
277
278 mv64x60_wdt_regs = ioremap(r->start, r->end - r->start + 1);
279 if (mv64x60_wdt_regs == NULL)
280 return -ENOMEM;
281
282 mv64x60_wdt_set_timeout(timeout);
283
284 mv64x60_wdt_handler_disable();
285
286 return misc_register(&mv64x60_wdt_miscdev);
287}
288
289static int __devexit mv64x60_wdt_remove(struct platform_device *dev)
290{
291 misc_deregister(&mv64x60_wdt_miscdev);
292
293 mv64x60_wdt_handler_disable();
294
295 iounmap(mv64x60_wdt_regs);
296
297 return 0;
298}
299
300static struct platform_driver mv64x60_wdt_driver = {
301 .probe = mv64x60_wdt_probe,
302 .remove = __devexit_p(mv64x60_wdt_remove),
303 .driver = {
304 .owner = THIS_MODULE,
305 .name = MV64x60_WDT_NAME,
306 },
307};
308
309static int __init mv64x60_wdt_init(void)
310{
311 printk(KERN_INFO "MV64x60 watchdog driver\n");
312
313 return platform_driver_register(&mv64x60_wdt_driver);
314}
315
316static void __exit mv64x60_wdt_exit(void)
317{
318 platform_driver_unregister(&mv64x60_wdt_driver);
319}
320
321module_init(mv64x60_wdt_init);
322module_exit(mv64x60_wdt_exit);
323
324MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
325MODULE_DESCRIPTION("MV64x60 watchdog driver");
326MODULE_LICENSE("GPL");
327MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
328MODULE_ALIAS("platform:" MV64x60_WDT_NAME);
329
