diff options
Diffstat (limited to 'drivers/watchdog/of_xilinx_wdt.c')
-rw-r--r-- | drivers/watchdog/of_xilinx_wdt.c | 433 |
1 files changed, 433 insertions, 0 deletions
diff --git a/drivers/watchdog/of_xilinx_wdt.c b/drivers/watchdog/of_xilinx_wdt.c new file mode 100644 index 000000000000..4ec741ac952c --- /dev/null +++ b/drivers/watchdog/of_xilinx_wdt.c | |||
@@ -0,0 +1,433 @@ | |||
1 | /* | ||
2 | * of_xilinx_wdt.c 1.01 A Watchdog Device Driver for Xilinx xps_timebase_wdt | ||
3 | * | ||
4 | * (C) Copyright 2011 (Alejandro Cabrera <aldaya@gmail.com>) | ||
5 | * | ||
6 | * ----------------------- | ||
7 | * | ||
8 | * This program is free software; you can redistribute it and/or | ||
9 | * modify it under the terms of the GNU General Public License | ||
10 | * as published by the Free Software Foundation; either version | ||
11 | * 2 of the License, or (at your option) any later version. | ||
12 | * | ||
13 | * ----------------------- | ||
14 | * 30-May-2011 Alejandro Cabrera <aldaya@gmail.com> | ||
15 | * - If "xlnx,wdt-enable-once" wasn't found on device tree the | ||
16 | * module will use CONFIG_WATCHDOG_NOWAYOUT | ||
17 | * - If the device tree parameters ("clock-frequency" and | ||
18 | * "xlnx,wdt-interval") wasn't found the driver won't | ||
19 | * know the wdt reset interval | ||
20 | */ | ||
21 | |||
22 | #include <linux/module.h> | ||
23 | #include <linux/types.h> | ||
24 | #include <linux/kernel.h> | ||
25 | #include <linux/fs.h> | ||
26 | #include <linux/miscdevice.h> | ||
27 | #include <linux/init.h> | ||
28 | #include <linux/ioport.h> | ||
29 | #include <linux/watchdog.h> | ||
30 | #include <linux/io.h> | ||
31 | #include <linux/uaccess.h> | ||
32 | #include <linux/of.h> | ||
33 | #include <linux/of_device.h> | ||
34 | #include <linux/of_address.h> | ||
35 | |||
36 | /* Register offsets for the Wdt device */ | ||
37 | #define XWT_TWCSR0_OFFSET 0x0 /* Control/Status Register0 */ | ||
38 | #define XWT_TWCSR1_OFFSET 0x4 /* Control/Status Register1 */ | ||
39 | #define XWT_TBR_OFFSET 0x8 /* Timebase Register Offset */ | ||
40 | |||
41 | /* Control/Status Register Masks */ | ||
42 | #define XWT_CSR0_WRS_MASK 0x00000008 /* Reset status */ | ||
43 | #define XWT_CSR0_WDS_MASK 0x00000004 /* Timer state */ | ||
44 | #define XWT_CSR0_EWDT1_MASK 0x00000002 /* Enable bit 1 */ | ||
45 | |||
46 | /* Control/Status Register 0/1 bits */ | ||
47 | #define XWT_CSRX_EWDT2_MASK 0x00000001 /* Enable bit 2 */ | ||
48 | |||
49 | /* SelfTest constants */ | ||
50 | #define XWT_MAX_SELFTEST_LOOP_COUNT 0x00010000 | ||
51 | #define XWT_TIMER_FAILED 0xFFFFFFFF | ||
52 | |||
53 | #define WATCHDOG_NAME "Xilinx Watchdog" | ||
54 | #define PFX WATCHDOG_NAME ": " | ||
55 | |||
56 | struct xwdt_device { | ||
57 | struct resource res; | ||
58 | void __iomem *base; | ||
59 | u32 nowayout; | ||
60 | u32 wdt_interval; | ||
61 | u32 boot_status; | ||
62 | }; | ||
63 | |||
64 | static struct xwdt_device xdev; | ||
65 | |||
66 | static u32 timeout; | ||
67 | static u32 control_status_reg; | ||
68 | static u8 expect_close; | ||
69 | static u8 no_timeout; | ||
70 | static unsigned long driver_open; | ||
71 | |||
72 | static DEFINE_SPINLOCK(spinlock); | ||
73 | |||
74 | static void xwdt_start(void) | ||
75 | { | ||
76 | spin_lock(&spinlock); | ||
77 | |||
78 | /* Clean previous status and enable the watchdog timer */ | ||
79 | control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET); | ||
80 | control_status_reg |= (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK); | ||
81 | |||
82 | iowrite32((control_status_reg | XWT_CSR0_EWDT1_MASK), | ||
83 | xdev.base + XWT_TWCSR0_OFFSET); | ||
84 | |||
85 | iowrite32(XWT_CSRX_EWDT2_MASK, xdev.base + XWT_TWCSR1_OFFSET); | ||
86 | |||
87 | spin_unlock(&spinlock); | ||
88 | } | ||
89 | |||
90 | static void xwdt_stop(void) | ||
91 | { | ||
92 | spin_lock(&spinlock); | ||
93 | |||
94 | control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET); | ||
95 | |||
96 | iowrite32((control_status_reg & ~XWT_CSR0_EWDT1_MASK), | ||
97 | xdev.base + XWT_TWCSR0_OFFSET); | ||
98 | |||
99 | iowrite32(0, xdev.base + XWT_TWCSR1_OFFSET); | ||
100 | |||
101 | spin_unlock(&spinlock); | ||
102 | printk(KERN_INFO PFX "Stopped!\n"); | ||
103 | } | ||
104 | |||
105 | static void xwdt_keepalive(void) | ||
106 | { | ||
107 | spin_lock(&spinlock); | ||
108 | |||
109 | control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET); | ||
110 | control_status_reg |= (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK); | ||
111 | iowrite32(control_status_reg, xdev.base + XWT_TWCSR0_OFFSET); | ||
112 | |||
113 | spin_unlock(&spinlock); | ||
114 | } | ||
115 | |||
116 | static void xwdt_get_status(int *status) | ||
117 | { | ||
118 | int new_status; | ||
119 | |||
120 | spin_lock(&spinlock); | ||
121 | |||
122 | control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET); | ||
123 | new_status = ((control_status_reg & | ||
124 | (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK)) != 0); | ||
125 | spin_unlock(&spinlock); | ||
126 | |||
127 | *status = 0; | ||
128 | if (new_status & 1) | ||
129 | *status |= WDIOF_CARDRESET; | ||
130 | } | ||
131 | |||
132 | static u32 xwdt_selftest(void) | ||
133 | { | ||
134 | int i; | ||
135 | u32 timer_value1; | ||
136 | u32 timer_value2; | ||
137 | |||
138 | spin_lock(&spinlock); | ||
139 | |||
140 | timer_value1 = ioread32(xdev.base + XWT_TBR_OFFSET); | ||
141 | timer_value2 = ioread32(xdev.base + XWT_TBR_OFFSET); | ||
142 | |||
143 | for (i = 0; | ||
144 | ((i <= XWT_MAX_SELFTEST_LOOP_COUNT) && | ||
145 | (timer_value2 == timer_value1)); i++) { | ||
146 | timer_value2 = ioread32(xdev.base + XWT_TBR_OFFSET); | ||
147 | } | ||
148 | |||
149 | spin_unlock(&spinlock); | ||
150 | |||
151 | if (timer_value2 != timer_value1) | ||
152 | return ~XWT_TIMER_FAILED; | ||
153 | else | ||
154 | return XWT_TIMER_FAILED; | ||
155 | } | ||
156 | |||
157 | static int xwdt_open(struct inode *inode, struct file *file) | ||
158 | { | ||
159 | /* Only one process can handle the wdt at a time */ | ||
160 | if (test_and_set_bit(0, &driver_open)) | ||
161 | return -EBUSY; | ||
162 | |||
163 | /* Make sure that the module are always loaded...*/ | ||
164 | if (xdev.nowayout) | ||
165 | __module_get(THIS_MODULE); | ||
166 | |||
167 | xwdt_start(); | ||
168 | printk(KERN_INFO PFX "Started...\n"); | ||
169 | |||
170 | return nonseekable_open(inode, file); | ||
171 | } | ||
172 | |||
173 | static int xwdt_release(struct inode *inode, struct file *file) | ||
174 | { | ||
175 | if (expect_close == 42) { | ||
176 | xwdt_stop(); | ||
177 | } else { | ||
178 | printk(KERN_CRIT PFX | ||
179 | "Unexpected close, not stopping watchdog!\n"); | ||
180 | xwdt_keepalive(); | ||
181 | } | ||
182 | |||
183 | clear_bit(0, &driver_open); | ||
184 | expect_close = 0; | ||
185 | return 0; | ||
186 | } | ||
187 | |||
188 | /* | ||
189 | * xwdt_write: | ||
190 | * @file: file handle to the watchdog | ||
191 | * @buf: buffer to write (unused as data does not matter here | ||
192 | * @count: count of bytes | ||
193 | * @ppos: pointer to the position to write. No seeks allowed | ||
194 | * | ||
195 | * A write to a watchdog device is defined as a keepalive signal. Any | ||
196 | * write of data will do, as we don't define content meaning. | ||
197 | */ | ||
198 | static ssize_t xwdt_write(struct file *file, const char __user *buf, | ||
199 | size_t len, loff_t *ppos) | ||
200 | { | ||
201 | if (len) { | ||
202 | if (!xdev.nowayout) { | ||
203 | size_t i; | ||
204 | |||
205 | /* In case it was set long ago */ | ||
206 | expect_close = 0; | ||
207 | |||
208 | for (i = 0; i != len; i++) { | ||
209 | char c; | ||
210 | |||
211 | if (get_user(c, buf + i)) | ||
212 | return -EFAULT; | ||
213 | if (c == 'V') | ||
214 | expect_close = 42; | ||
215 | } | ||
216 | } | ||
217 | xwdt_keepalive(); | ||
218 | } | ||
219 | return len; | ||
220 | } | ||
221 | |||
222 | static const struct watchdog_info ident = { | ||
223 | .options = WDIOF_MAGICCLOSE | | ||
224 | WDIOF_KEEPALIVEPING, | ||
225 | .firmware_version = 1, | ||
226 | .identity = WATCHDOG_NAME, | ||
227 | }; | ||
228 | |||
229 | /* | ||
230 | * xwdt_ioctl: | ||
231 | * @file: file handle to the device | ||
232 | * @cmd: watchdog command | ||
233 | * @arg: argument pointer | ||
234 | * | ||
235 | * The watchdog API defines a common set of functions for all watchdogs | ||
236 | * according to their available features. | ||
237 | */ | ||
238 | static long xwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | ||
239 | { | ||
240 | int status; | ||
241 | |||
242 | union { | ||
243 | struct watchdog_info __user *ident; | ||
244 | int __user *i; | ||
245 | } uarg; | ||
246 | |||
247 | uarg.i = (int __user *)arg; | ||
248 | |||
249 | switch (cmd) { | ||
250 | case WDIOC_GETSUPPORT: | ||
251 | return copy_to_user(uarg.ident, &ident, | ||
252 | sizeof(ident)) ? -EFAULT : 0; | ||
253 | |||
254 | case WDIOC_GETBOOTSTATUS: | ||
255 | return put_user(xdev.boot_status, uarg.i); | ||
256 | |||
257 | case WDIOC_GETSTATUS: | ||
258 | xwdt_get_status(&status); | ||
259 | return put_user(status, uarg.i); | ||
260 | |||
261 | case WDIOC_KEEPALIVE: | ||
262 | xwdt_keepalive(); | ||
263 | return 0; | ||
264 | |||
265 | case WDIOC_GETTIMEOUT: | ||
266 | if (no_timeout) | ||
267 | return -ENOTTY; | ||
268 | else | ||
269 | return put_user(timeout, uarg.i); | ||
270 | |||
271 | default: | ||
272 | return -ENOTTY; | ||
273 | } | ||
274 | } | ||
275 | |||
276 | static const struct file_operations xwdt_fops = { | ||
277 | .owner = THIS_MODULE, | ||
278 | .llseek = no_llseek, | ||
279 | .write = xwdt_write, | ||
280 | .open = xwdt_open, | ||
281 | .release = xwdt_release, | ||
282 | .unlocked_ioctl = xwdt_ioctl, | ||
283 | }; | ||
284 | |||
285 | static struct miscdevice xwdt_miscdev = { | ||
286 | .minor = WATCHDOG_MINOR, | ||
287 | .name = "watchdog", | ||
288 | .fops = &xwdt_fops, | ||
289 | }; | ||
290 | |||
291 | static int __devinit xwdt_probe(struct platform_device *pdev) | ||
292 | { | ||
293 | int rc; | ||
294 | u32 *tmptr; | ||
295 | u32 *pfreq; | ||
296 | |||
297 | no_timeout = 0; | ||
298 | |||
299 | pfreq = (u32 *)of_get_property(pdev->dev.of_node->parent, | ||
300 | "clock-frequency", NULL); | ||
301 | |||
302 | if (pfreq == NULL) { | ||
303 | printk(KERN_WARNING PFX | ||
304 | "The watchdog clock frequency cannot be obtained!\n"); | ||
305 | no_timeout = 1; | ||
306 | } | ||
307 | |||
308 | rc = of_address_to_resource(pdev->dev.of_node, 0, &xdev.res); | ||
309 | if (rc) { | ||
310 | printk(KERN_WARNING PFX "invalid address!\n"); | ||
311 | return rc; | ||
312 | } | ||
313 | |||
314 | tmptr = (u32 *)of_get_property(pdev->dev.of_node, | ||
315 | "xlnx,wdt-interval", NULL); | ||
316 | if (tmptr == NULL) { | ||
317 | printk(KERN_WARNING PFX "Parameter \"xlnx,wdt-interval\"" | ||
318 | " not found in device tree!\n"); | ||
319 | no_timeout = 1; | ||
320 | } else { | ||
321 | xdev.wdt_interval = *tmptr; | ||
322 | } | ||
323 | |||
324 | tmptr = (u32 *)of_get_property(pdev->dev.of_node, | ||
325 | "xlnx,wdt-enable-once", NULL); | ||
326 | if (tmptr == NULL) { | ||
327 | printk(KERN_WARNING PFX "Parameter \"xlnx,wdt-enable-once\"" | ||
328 | " not found in device tree!\n"); | ||
329 | xdev.nowayout = WATCHDOG_NOWAYOUT; | ||
330 | } | ||
331 | |||
332 | /* | ||
333 | * Twice of the 2^wdt_interval / freq because the first wdt overflow is | ||
334 | * ignored (interrupt), reset is only generated at second wdt overflow | ||
335 | */ | ||
336 | if (!no_timeout) | ||
337 | timeout = 2 * ((1<<xdev.wdt_interval) / *pfreq); | ||
338 | |||
339 | if (!request_mem_region(xdev.res.start, | ||
340 | xdev.res.end - xdev.res.start + 1, WATCHDOG_NAME)) { | ||
341 | rc = -ENXIO; | ||
342 | printk(KERN_ERR PFX "memory request failure!\n"); | ||
343 | goto err_out; | ||
344 | } | ||
345 | |||
346 | xdev.base = ioremap(xdev.res.start, xdev.res.end - xdev.res.start + 1); | ||
347 | if (xdev.base == NULL) { | ||
348 | rc = -ENOMEM; | ||
349 | printk(KERN_ERR PFX "ioremap failure!\n"); | ||
350 | goto release_mem; | ||
351 | } | ||
352 | |||
353 | rc = xwdt_selftest(); | ||
354 | if (rc == XWT_TIMER_FAILED) { | ||
355 | printk(KERN_ERR PFX "SelfTest routine error!\n"); | ||
356 | goto unmap_io; | ||
357 | } | ||
358 | |||
359 | xwdt_get_status(&xdev.boot_status); | ||
360 | |||
361 | rc = misc_register(&xwdt_miscdev); | ||
362 | if (rc) { | ||
363 | printk(KERN_ERR PFX | ||
364 | "cannot register miscdev on minor=%d (err=%d)\n", | ||
365 | xwdt_miscdev.minor, rc); | ||
366 | goto unmap_io; | ||
367 | } | ||
368 | |||
369 | if (no_timeout) | ||
370 | printk(KERN_INFO PFX | ||
371 | "driver loaded (timeout=? sec, nowayout=%d)\n", | ||
372 | xdev.nowayout); | ||
373 | else | ||
374 | printk(KERN_INFO PFX | ||
375 | "driver loaded (timeout=%d sec, nowayout=%d)\n", | ||
376 | timeout, xdev.nowayout); | ||
377 | |||
378 | expect_close = 0; | ||
379 | clear_bit(0, &driver_open); | ||
380 | |||
381 | return 0; | ||
382 | |||
383 | unmap_io: | ||
384 | iounmap(xdev.base); | ||
385 | release_mem: | ||
386 | release_mem_region(xdev.res.start, resource_size(&xdev.res)); | ||
387 | err_out: | ||
388 | return rc; | ||
389 | } | ||
390 | |||
391 | static int __devexit xwdt_remove(struct platform_device *dev) | ||
392 | { | ||
393 | misc_deregister(&xwdt_miscdev); | ||
394 | iounmap(xdev.base); | ||
395 | release_mem_region(xdev.res.start, resource_size(&xdev.res)); | ||
396 | |||
397 | return 0; | ||
398 | } | ||
399 | |||
400 | /* Match table for of_platform binding */ | ||
401 | static struct of_device_id __devinitdata xwdt_of_match[] = { | ||
402 | { .compatible = "xlnx,xps-timebase-wdt-1.01.a", }, | ||
403 | {}, | ||
404 | }; | ||
405 | MODULE_DEVICE_TABLE(of, xwdt_of_match); | ||
406 | |||
407 | static struct platform_driver xwdt_driver = { | ||
408 | .probe = xwdt_probe, | ||
409 | .remove = __devexit_p(xwdt_remove), | ||
410 | .driver = { | ||
411 | .owner = THIS_MODULE, | ||
412 | .name = WATCHDOG_NAME, | ||
413 | .of_match_table = xwdt_of_match, | ||
414 | }, | ||
415 | }; | ||
416 | |||
417 | static int __init xwdt_init(void) | ||
418 | { | ||
419 | return platform_driver_register(&xwdt_driver); | ||
420 | } | ||
421 | |||
422 | static void __exit xwdt_exit(void) | ||
423 | { | ||
424 | platform_driver_unregister(&xwdt_driver); | ||
425 | } | ||
426 | |||
427 | module_init(xwdt_init); | ||
428 | module_exit(xwdt_exit); | ||
429 | |||
430 | MODULE_AUTHOR("Alejandro Cabrera <aldaya@gmail.com>"); | ||
431 | MODULE_DESCRIPTION("Xilinx Watchdog driver"); | ||
432 | MODULE_LICENSE("GPL"); | ||
433 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | ||