1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27#include <linux/kernel.h>
28#include <linux/compiler.h>
29#include <linux/init.h>
30#include <linux/module.h>
31#include <linux/miscdevice.h>
32#include <linux/watchdog.h>
33#include <linux/fs.h>
34#include <linux/of.h>
35#include <linux/of_platform.h>
36#include <linux/io.h>
37#include <linux/uaccess.h>
38
39#include <sysdev/fsl_soc.h>
40
41
42
43
44
45
46
47
48
49
50
51
52#define GEF_WDC_ENABLE_SHIFT 24
53#define GEF_WDC_SERVICE_SHIFT 26
54#define GEF_WDC_ENABLED_SHIFT 31
55
56#define GEF_WDC_ENABLED_TRUE 1
57#define GEF_WDC_ENABLED_FALSE 0
58
59
60#define GEF_WDOG_FLAG_OPENED 0
61
62static unsigned long wdt_flags;
63static int wdt_status;
64static void __iomem *gef_wdt_regs;
65static int gef_wdt_timeout;
66static int gef_wdt_count;
67static unsigned int bus_clk;
68static char expect_close;
69static DEFINE_SPINLOCK(gef_wdt_spinlock);
70
71static int nowayout = WATCHDOG_NOWAYOUT;
72module_param(nowayout, int, 0);
73MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
74 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
75
76
77static int gef_wdt_toggle_wdc(int enabled_predicate, int field_shift)
78{
79 u32 data;
80 u32 enabled;
81 int ret = 0;
82
83 spin_lock(&gef_wdt_spinlock);
84 data = ioread32be(gef_wdt_regs);
85 enabled = (data >> GEF_WDC_ENABLED_SHIFT) & 1;
86
87
88 if ((enabled ^ enabled_predicate) == 0) {
89
90 data = (1 << field_shift) | gef_wdt_count;
91 iowrite32be(data, gef_wdt_regs);
92
93 data = (2 << field_shift) | gef_wdt_count;
94 iowrite32be(data, gef_wdt_regs);
95 ret = 1;
96 }
97 spin_unlock(&gef_wdt_spinlock);
98
99 return ret;
100}
101
102static void gef_wdt_service(void)
103{
104 gef_wdt_toggle_wdc(GEF_WDC_ENABLED_TRUE,
105 GEF_WDC_SERVICE_SHIFT);
106}
107
108static void gef_wdt_handler_enable(void)
109{
110 if (gef_wdt_toggle_wdc(GEF_WDC_ENABLED_FALSE,
111 GEF_WDC_ENABLE_SHIFT)) {
112 gef_wdt_service();
113 printk(KERN_NOTICE "gef_wdt: watchdog activated\n");
114 }
115}
116
117static void gef_wdt_handler_disable(void)
118{
119 if (gef_wdt_toggle_wdc(GEF_WDC_ENABLED_TRUE,
120 GEF_WDC_ENABLE_SHIFT))
121 printk(KERN_NOTICE "gef_wdt: watchdog deactivated\n");
122}
123
124static void gef_wdt_set_timeout(unsigned int timeout)
125{
126
127 if (timeout > 0xFFFFFFFF / bus_clk)
128 timeout = 0xFFFFFFFF / bus_clk;
129
130
131 gef_wdt_count = (timeout * bus_clk) >> 8;
132 gef_wdt_timeout = timeout;
133}
134
135
136static ssize_t gef_wdt_write(struct file *file, const char __user *data,
137 size_t len, loff_t *ppos)
138{
139 if (len) {
140 if (!nowayout) {
141 size_t i;
142
143 expect_close = 0;
144
145 for (i = 0; i != len; i++) {
146 char c;
147 if (get_user(c, data + i))
148 return -EFAULT;
149 if (c == 'V')
150 expect_close = 42;
151 }
152 }
153 gef_wdt_service();
154 }
155
156 return len;
157}
158
159static long gef_wdt_ioctl(struct file *file, unsigned int cmd,
160 unsigned long arg)
161{
162 int timeout;
163 int options;
164 void __user *argp = (void __user *)arg;
165 static const struct watchdog_info info = {
166 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
167 WDIOF_KEEPALIVEPING,
168 .firmware_version = 0,
169 .identity = "GE watchdog",
170 };
171
172 switch (cmd) {
173 case WDIOC_GETSUPPORT:
174 if (copy_to_user(argp, &info, sizeof(info)))
175 return -EFAULT;
176 break;
177
178 case WDIOC_GETSTATUS:
179 case WDIOC_GETBOOTSTATUS:
180 if (put_user(wdt_status, (int __user *)argp))
181 return -EFAULT;
182 wdt_status &= ~WDIOF_KEEPALIVEPING;
183 break;
184
185 case WDIOC_SETOPTIONS:
186 if (get_user(options, (int __user *)argp))
187 return -EFAULT;
188
189 if (options & WDIOS_DISABLECARD)
190 gef_wdt_handler_disable();
191
192 if (options & WDIOS_ENABLECARD)
193 gef_wdt_handler_enable();
194 break;
195
196 case WDIOC_KEEPALIVE:
197 gef_wdt_service();
198 wdt_status |= WDIOF_KEEPALIVEPING;
199 break;
200
201 case WDIOC_SETTIMEOUT:
202 if (get_user(timeout, (int __user *)argp))
203 return -EFAULT;
204 gef_wdt_set_timeout(timeout);
205
206
207 case WDIOC_GETTIMEOUT:
208 if (put_user(gef_wdt_timeout, (int __user *)argp))
209 return -EFAULT;
210 break;
211
212 default:
213 return -ENOTTY;
214 }
215
216 return 0;
217}
218
219static int gef_wdt_open(struct inode *inode, struct file *file)
220{
221 if (test_and_set_bit(GEF_WDOG_FLAG_OPENED, &wdt_flags))
222 return -EBUSY;
223
224 if (nowayout)
225 __module_get(THIS_MODULE);
226
227 gef_wdt_handler_enable();
228
229 return nonseekable_open(inode, file);
230}
231
232static int gef_wdt_release(struct inode *inode, struct file *file)
233{
234 if (expect_close == 42)
235 gef_wdt_handler_disable();
236 else {
237 printk(KERN_CRIT
238 "gef_wdt: unexpected close, not stopping timer!\n");
239 gef_wdt_service();
240 }
241 expect_close = 0;
242
243 clear_bit(GEF_WDOG_FLAG_OPENED, &wdt_flags);
244
245 return 0;
246}
247
248static const struct file_operations gef_wdt_fops = {
249 .owner = THIS_MODULE,
250 .llseek = no_llseek,
251 .write = gef_wdt_write,
252 .unlocked_ioctl = gef_wdt_ioctl,
253 .open = gef_wdt_open,
254 .release = gef_wdt_release,
255};
256
257static struct miscdevice gef_wdt_miscdev = {
258 .minor = WATCHDOG_MINOR,
259 .name = "watchdog",
260 .fops = &gef_wdt_fops,
261};
262
263
264static int __devinit gef_wdt_probe(struct platform_device *dev)
265{
266 int timeout = 10;
267 u32 freq;
268
269 bus_clk = 133;
270
271 freq = fsl_get_sys_freq();
272 if (freq != -1)
273 bus_clk = freq;
274
275
276 gef_wdt_regs = of_iomap(dev->dev.of_node, 0);
277 if (gef_wdt_regs == NULL)
278 return -ENOMEM;
279
280 gef_wdt_set_timeout(timeout);
281
282 gef_wdt_handler_disable();
283
284 return misc_register(&gef_wdt_miscdev);
285}
286
287static int __devexit gef_wdt_remove(struct platform_device *dev)
288{
289 misc_deregister(&gef_wdt_miscdev);
290
291 gef_wdt_handler_disable();
292
293 iounmap(gef_wdt_regs);
294
295 return 0;
296}
297
298static const struct of_device_id gef_wdt_ids[] = {
299 {
300 .compatible = "gef,fpga-wdt",
301 },
302 {},
303};
304
305static struct platform_driver gef_wdt_driver = {
306 .driver = {
307 .name = "gef_wdt",
308 .owner = THIS_MODULE,
309 .of_match_table = gef_wdt_ids,
310 },
311 .probe = gef_wdt_probe,
312};
313
314static int __init gef_wdt_init(void)
315{
316 printk(KERN_INFO "GE watchdog driver\n");
317 return platform_driver_register(&gef_wdt_driver);
318}
319
320static void __exit gef_wdt_exit(void)
321{
322 platform_driver_unregister(&gef_wdt_driver);
323}
324
325module_init(gef_wdt_init);
326module_exit(gef_wdt_exit);
327
328MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
329MODULE_DESCRIPTION("GE watchdog driver");
330MODULE_LICENSE("GPL");
331MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
332MODULE_ALIAS("platform:gef_wdt");
333
