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26#include <linux/module.h>
27#include <linux/moduleparam.h>
28#include <linux/errno.h>
29#include <linux/init.h>
30#include <linux/miscdevice.h>
31#include <linux/platform_device.h>
32#include <linux/watchdog.h>
33#include <linux/fs.h>
34#include <linux/ioport.h>
35#include <linux/io.h>
36#include <linux/uaccess.h>
37#include <linux/clk.h>
38
39#include <asm/addrspace.h>
40#include <asm/mach-ar7/ar7.h>
41
42#define DRVNAME "ar7_wdt"
43#define LONGNAME "TI AR7 Watchdog Timer"
44
45MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>");
46MODULE_DESCRIPTION(LONGNAME);
47MODULE_LICENSE("GPL");
48MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
49
50static int margin = 60;
51module_param(margin, int, 0);
52MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
53
54static int nowayout = WATCHDOG_NOWAYOUT;
55module_param(nowayout, int, 0);
56MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
57
58#define READ_REG(x) readl((void __iomem *)&(x))
59#define WRITE_REG(x, v) writel((v), (void __iomem *)&(x))
60
61struct ar7_wdt {
62 u32 kick_lock;
63 u32 kick;
64 u32 change_lock;
65 u32 change;
66 u32 disable_lock;
67 u32 disable;
68 u32 prescale_lock;
69 u32 prescale;
70};
71
72static unsigned long wdt_is_open;
73static unsigned expect_close;
74static DEFINE_SPINLOCK(wdt_lock);
75
76
77#define prescale_value 0xffff
78
79
80static struct resource *ar7_regs_wdt;
81
82static struct ar7_wdt *ar7_wdt;
83
84static struct clk *vbus_clk;
85
86static void ar7_wdt_kick(u32 value)
87{
88 WRITE_REG(ar7_wdt->kick_lock, 0x5555);
89 if ((READ_REG(ar7_wdt->kick_lock) & 3) == 1) {
90 WRITE_REG(ar7_wdt->kick_lock, 0xaaaa);
91 if ((READ_REG(ar7_wdt->kick_lock) & 3) == 3) {
92 WRITE_REG(ar7_wdt->kick, value);
93 return;
94 }
95 }
96 printk(KERN_ERR DRVNAME ": failed to unlock WDT kick reg\n");
97}
98
99static void ar7_wdt_prescale(u32 value)
100{
101 WRITE_REG(ar7_wdt->prescale_lock, 0x5a5a);
102 if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 1) {
103 WRITE_REG(ar7_wdt->prescale_lock, 0xa5a5);
104 if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 3) {
105 WRITE_REG(ar7_wdt->prescale, value);
106 return;
107 }
108 }
109 printk(KERN_ERR DRVNAME ": failed to unlock WDT prescale reg\n");
110}
111
112static void ar7_wdt_change(u32 value)
113{
114 WRITE_REG(ar7_wdt->change_lock, 0x6666);
115 if ((READ_REG(ar7_wdt->change_lock) & 3) == 1) {
116 WRITE_REG(ar7_wdt->change_lock, 0xbbbb);
117 if ((READ_REG(ar7_wdt->change_lock) & 3) == 3) {
118 WRITE_REG(ar7_wdt->change, value);
119 return;
120 }
121 }
122 printk(KERN_ERR DRVNAME ": failed to unlock WDT change reg\n");
123}
124
125static void ar7_wdt_disable(u32 value)
126{
127 WRITE_REG(ar7_wdt->disable_lock, 0x7777);
128 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 1) {
129 WRITE_REG(ar7_wdt->disable_lock, 0xcccc);
130 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 2) {
131 WRITE_REG(ar7_wdt->disable_lock, 0xdddd);
132 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 3) {
133 WRITE_REG(ar7_wdt->disable, value);
134 return;
135 }
136 }
137 }
138 printk(KERN_ERR DRVNAME ": failed to unlock WDT disable reg\n");
139}
140
141static void ar7_wdt_update_margin(int new_margin)
142{
143 u32 change;
144 u32 vbus_rate;
145
146 vbus_rate = clk_get_rate(vbus_clk);
147 change = new_margin * (vbus_rate / prescale_value);
148 if (change < 1)
149 change = 1;
150 if (change > 0xffff)
151 change = 0xffff;
152 ar7_wdt_change(change);
153 margin = change * prescale_value / vbus_rate;
154 printk(KERN_INFO DRVNAME
155 ": timer margin %d seconds (prescale %d, change %d, freq %d)\n",
156 margin, prescale_value, change, vbus_rate);
157}
158
159static void ar7_wdt_enable_wdt(void)
160{
161 printk(KERN_DEBUG DRVNAME ": enabling watchdog timer\n");
162 ar7_wdt_disable(1);
163 ar7_wdt_kick(1);
164}
165
166static void ar7_wdt_disable_wdt(void)
167{
168 printk(KERN_DEBUG DRVNAME ": disabling watchdog timer\n");
169 ar7_wdt_disable(0);
170}
171
172static int ar7_wdt_open(struct inode *inode, struct file *file)
173{
174
175 if (test_and_set_bit(0, &wdt_is_open))
176 return -EBUSY;
177 ar7_wdt_enable_wdt();
178 expect_close = 0;
179
180 return nonseekable_open(inode, file);
181}
182
183static int ar7_wdt_release(struct inode *inode, struct file *file)
184{
185 if (!expect_close)
186 printk(KERN_WARNING DRVNAME
187 ": watchdog device closed unexpectedly,"
188 "will not disable the watchdog timer\n");
189 else if (!nowayout)
190 ar7_wdt_disable_wdt();
191 clear_bit(0, &wdt_is_open);
192 return 0;
193}
194
195static ssize_t ar7_wdt_write(struct file *file, const char *data,
196 size_t len, loff_t *ppos)
197{
198
199 if (len) {
200 size_t i;
201
202 spin_lock(&wdt_lock);
203 ar7_wdt_kick(1);
204 spin_unlock(&wdt_lock);
205
206 expect_close = 0;
207 for (i = 0; i < len; ++i) {
208 char c;
209 if (get_user(c, data + i))
210 return -EFAULT;
211 if (c == 'V')
212 expect_close = 1;
213 }
214
215 }
216 return len;
217}
218
219static long ar7_wdt_ioctl(struct file *file,
220 unsigned int cmd, unsigned long arg)
221{
222 static const struct watchdog_info ident = {
223 .identity = LONGNAME,
224 .firmware_version = 1,
225 .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
226 WDIOF_MAGICCLOSE),
227 };
228 int new_margin;
229
230 switch (cmd) {
231 case WDIOC_GETSUPPORT:
232 if (copy_to_user((struct watchdog_info *)arg, &ident,
233 sizeof(ident)))
234 return -EFAULT;
235 return 0;
236 case WDIOC_GETSTATUS:
237 case WDIOC_GETBOOTSTATUS:
238 if (put_user(0, (int *)arg))
239 return -EFAULT;
240 return 0;
241 case WDIOC_KEEPALIVE:
242 ar7_wdt_kick(1);
243 return 0;
244 case WDIOC_SETTIMEOUT:
245 if (get_user(new_margin, (int *)arg))
246 return -EFAULT;
247 if (new_margin < 1)
248 return -EINVAL;
249
250 spin_lock(&wdt_lock);
251 ar7_wdt_update_margin(new_margin);
252 ar7_wdt_kick(1);
253 spin_unlock(&wdt_lock);
254
255 case WDIOC_GETTIMEOUT:
256 if (put_user(margin, (int *)arg))
257 return -EFAULT;
258 return 0;
259 default:
260 return -ENOTTY;
261 }
262}
263
264static const struct file_operations ar7_wdt_fops = {
265 .owner = THIS_MODULE,
266 .write = ar7_wdt_write,
267 .unlocked_ioctl = ar7_wdt_ioctl,
268 .open = ar7_wdt_open,
269 .release = ar7_wdt_release,
270 .llseek = no_llseek,
271};
272
273static struct miscdevice ar7_wdt_miscdev = {
274 .minor = WATCHDOG_MINOR,
275 .name = "watchdog",
276 .fops = &ar7_wdt_fops,
277};
278
279static int __devinit ar7_wdt_probe(struct platform_device *pdev)
280{
281 int rc;
282
283 ar7_regs_wdt =
284 platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
285 if (!ar7_regs_wdt) {
286 printk(KERN_ERR DRVNAME ": could not get registers resource\n");
287 rc = -ENODEV;
288 goto out;
289 }
290
291 if (!request_mem_region(ar7_regs_wdt->start,
292 resource_size(ar7_regs_wdt), LONGNAME)) {
293 printk(KERN_WARNING DRVNAME ": watchdog I/O region busy\n");
294 rc = -EBUSY;
295 goto out;
296 }
297
298 ar7_wdt = ioremap(ar7_regs_wdt->start, resource_size(ar7_regs_wdt));
299 if (!ar7_wdt) {
300 printk(KERN_ERR DRVNAME ": could not ioremap registers\n");
301 rc = -ENXIO;
302 goto out_mem_region;
303 }
304
305 vbus_clk = clk_get(NULL, "vbus");
306 if (IS_ERR(vbus_clk)) {
307 printk(KERN_ERR DRVNAME ": could not get vbus clock\n");
308 rc = PTR_ERR(vbus_clk);
309 goto out_mem_region;
310 }
311
312 ar7_wdt_disable_wdt();
313 ar7_wdt_prescale(prescale_value);
314 ar7_wdt_update_margin(margin);
315
316 rc = misc_register(&ar7_wdt_miscdev);
317 if (rc) {
318 printk(KERN_ERR DRVNAME ": unable to register misc device\n");
319 goto out_alloc;
320 }
321 goto out;
322
323out_alloc:
324 iounmap(ar7_wdt);
325out_mem_region:
326 release_mem_region(ar7_regs_wdt->start, resource_size(ar7_regs_wdt));
327out:
328 return rc;
329}
330
331static int __devexit ar7_wdt_remove(struct platform_device *pdev)
332{
333 misc_deregister(&ar7_wdt_miscdev);
334 iounmap(ar7_wdt);
335 release_mem_region(ar7_regs_wdt->start, resource_size(ar7_regs_wdt));
336
337 return 0;
338}
339
340static void ar7_wdt_shutdown(struct platform_device *pdev)
341{
342 if (!nowayout)
343 ar7_wdt_disable_wdt();
344}
345
346static struct platform_driver ar7_wdt_driver = {
347 .probe = ar7_wdt_probe,
348 .remove = __devexit_p(ar7_wdt_remove),
349 .shutdown = ar7_wdt_shutdown,
350 .driver = {
351 .owner = THIS_MODULE,
352 .name = "ar7_wdt",
353 },
354};
355
356module_platform_driver(ar7_wdt_driver);
357
