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Bryan Wu1e6d3202007-07-15 02:50:02 +08001/*
2 * Blackfin On-Chip Watchdog Driver
Bryan Wu1e6d3202007-07-15 02:50:02 +08003 *
4 * Originally based on softdog.c
Mike Frysinger3dae93e2010-02-15 19:32:25 -05005 * Copyright 2006-2010 Analog Devices Inc.
Bryan Wu1e6d3202007-07-15 02:50:02 +08006 * Copyright 2006-2007 Michele d'Amico
Alan Cox29fa0582008-10-27 15:17:56 +00007 * Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>
Bryan Wu1e6d3202007-07-15 02:50:02 +08008 *
9 * Enter bugs at http://blackfin.uclinux.org/
10 *
11 * Licensed under the GPL-2 or later.
12 */
13
Joe Perches27c766a2012-02-15 15:06:19 -080014#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
Bryan Wu1e6d3202007-07-15 02:50:02 +080016#include <linux/platform_device.h>
17#include <linux/module.h>
18#include <linux/moduleparam.h>
19#include <linux/types.h>
20#include <linux/timer.h>
21#include <linux/miscdevice.h>
22#include <linux/watchdog.h>
23#include <linux/fs.h>
Bryan Wu1e6d3202007-07-15 02:50:02 +080024#include <linux/init.h>
25#include <linux/interrupt.h>
Alan Cox9a5f50d2008-05-19 14:06:30 +010026#include <linux/uaccess.h>
Wim Van Sebroeck089ab072008-07-15 11:46:11 +000027#include <asm/blackfin.h>
Mike Frysinger42bd5d42010-03-09 11:07:40 -050028#include <asm/bfin_watchdog.h>
Bryan Wu1e6d3202007-07-15 02:50:02 +080029
Wim Van Sebroecka77dba72009-04-14 20:20:07 +000030#define stamp(fmt, args...) \
31 pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
Bryan Wu1e6d3202007-07-15 02:50:02 +080032#define stampit() stamp("here i am")
33
34#define WATCHDOG_NAME "bfin-wdt"
Bryan Wu1e6d3202007-07-15 02:50:02 +080035
36/* The BF561 has two watchdogs (one per core), but since Linux
37 * only runs on core A, we'll just work with that one.
38 */
39#ifdef BF561_FAMILY
40# define bfin_read_WDOG_CTL() bfin_read_WDOGA_CTL()
41# define bfin_read_WDOG_CNT() bfin_read_WDOGA_CNT()
42# define bfin_read_WDOG_STAT() bfin_read_WDOGA_STAT()
43# define bfin_write_WDOG_CTL(x) bfin_write_WDOGA_CTL(x)
44# define bfin_write_WDOG_CNT(x) bfin_write_WDOGA_CNT(x)
45# define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x)
46#endif
47
Bryan Wu1e6d3202007-07-15 02:50:02 +080048/* some defaults */
49#define WATCHDOG_TIMEOUT 20
50
51static unsigned int timeout = WATCHDOG_TIMEOUT;
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010052static bool nowayout = WATCHDOG_NOWAYOUT;
Wim Van Sebroeck42747d72009-12-26 18:55:22 +000053static const struct watchdog_info bfin_wdt_info;
Bryan Wu1e6d3202007-07-15 02:50:02 +080054static unsigned long open_check;
55static char expect_close;
Jiri Slabybf6350a2007-11-10 05:58:44 +010056static DEFINE_SPINLOCK(bfin_wdt_spinlock);
Bryan Wu1e6d3202007-07-15 02:50:02 +080057
58/**
59 * bfin_wdt_keepalive - Keep the Userspace Watchdog Alive
60 *
Wim Van Sebroeck5f3b2752011-02-23 20:04:38 +000061 * The Userspace watchdog got a KeepAlive: schedule the next timeout.
Bryan Wu1e6d3202007-07-15 02:50:02 +080062 */
63static int bfin_wdt_keepalive(void)
64{
65 stampit();
66 bfin_write_WDOG_STAT(0);
67 return 0;
68}
69
70/**
71 * bfin_wdt_stop - Stop the Watchdog
72 *
73 * Stops the on-chip watchdog.
74 */
75static int bfin_wdt_stop(void)
76{
77 stampit();
78 bfin_write_WDOG_CTL(WDEN_DISABLE);
79 return 0;
80}
81
82/**
83 * bfin_wdt_start - Start the Watchdog
84 *
85 * Starts the on-chip watchdog. Automatically loads WDOG_CNT
86 * into WDOG_STAT for us.
87 */
88static int bfin_wdt_start(void)
89{
90 stampit();
91 bfin_write_WDOG_CTL(WDEN_ENABLE | ICTL_RESET);
92 return 0;
93}
94
95/**
96 * bfin_wdt_running - Check Watchdog status
97 *
98 * See if the watchdog is running.
99 */
100static int bfin_wdt_running(void)
101{
102 stampit();
103 return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE);
104}
105
106/**
107 * bfin_wdt_set_timeout - Set the Userspace Watchdog timeout
108 * @t: new timeout value (in seconds)
109 *
110 * Translate the specified timeout in seconds into System Clock
111 * terms which is what the on-chip Watchdog requires.
112 */
113static int bfin_wdt_set_timeout(unsigned long t)
114{
Mike Frysinger3dae93e2010-02-15 19:32:25 -0500115 u32 cnt, max_t, sclk;
Bryan Wu1e6d3202007-07-15 02:50:02 +0800116 unsigned long flags;
117
Mike Frysinger3dae93e2010-02-15 19:32:25 -0500118 sclk = get_sclk();
119 max_t = -1 / sclk;
120 cnt = t * sclk;
121 stamp("maxtimeout=%us newtimeout=%lus (cnt=%#x)", max_t, t, cnt);
Bryan Wu1e6d3202007-07-15 02:50:02 +0800122
Mike Frysinger3dae93e2010-02-15 19:32:25 -0500123 if (t > max_t) {
Joe Perches27c766a2012-02-15 15:06:19 -0800124 pr_warn("timeout value is too large\n");
Bryan Wu1e6d3202007-07-15 02:50:02 +0800125 return -EINVAL;
126 }
127
128 spin_lock_irqsave(&bfin_wdt_spinlock, flags);
129 {
130 int run = bfin_wdt_running();
131 bfin_wdt_stop();
132 bfin_write_WDOG_CNT(cnt);
Alan Cox9a5f50d2008-05-19 14:06:30 +0100133 if (run)
134 bfin_wdt_start();
Bryan Wu1e6d3202007-07-15 02:50:02 +0800135 }
136 spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
137
138 timeout = t;
139
140 return 0;
141}
142
143/**
144 * bfin_wdt_open - Open the Device
145 * @inode: inode of device
146 * @file: file handle of device
147 *
148 * Watchdog device is opened and started.
149 */
150static int bfin_wdt_open(struct inode *inode, struct file *file)
151{
152 stampit();
153
154 if (test_and_set_bit(0, &open_check))
155 return -EBUSY;
156
157 if (nowayout)
158 __module_get(THIS_MODULE);
159
160 bfin_wdt_keepalive();
161 bfin_wdt_start();
162
163 return nonseekable_open(inode, file);
164}
165
166/**
167 * bfin_wdt_close - Close the Device
168 * @inode: inode of device
169 * @file: file handle of device
170 *
171 * Watchdog device is closed and stopped.
172 */
173static int bfin_wdt_release(struct inode *inode, struct file *file)
174{
175 stampit();
176
Alan Cox9a5f50d2008-05-19 14:06:30 +0100177 if (expect_close == 42)
Bryan Wu1e6d3202007-07-15 02:50:02 +0800178 bfin_wdt_stop();
Alan Cox9a5f50d2008-05-19 14:06:30 +0100179 else {
Joe Perches27c766a2012-02-15 15:06:19 -0800180 pr_crit("Unexpected close, not stopping watchdog!\n");
Bryan Wu1e6d3202007-07-15 02:50:02 +0800181 bfin_wdt_keepalive();
182 }
Bryan Wu1e6d3202007-07-15 02:50:02 +0800183 expect_close = 0;
184 clear_bit(0, &open_check);
Bryan Wu1e6d3202007-07-15 02:50:02 +0800185 return 0;
186}
187
188/**
189 * bfin_wdt_write - Write to Device
190 * @file: file handle of device
191 * @buf: buffer to write
192 * @count: length of buffer
193 * @ppos: offset
194 *
195 * Pings the watchdog on write.
196 */
197static ssize_t bfin_wdt_write(struct file *file, const char __user *data,
Alan Cox9a5f50d2008-05-19 14:06:30 +0100198 size_t len, loff_t *ppos)
Bryan Wu1e6d3202007-07-15 02:50:02 +0800199{
200 stampit();
201
202 if (len) {
203 if (!nowayout) {
204 size_t i;
205
206 /* In case it was set long ago */
207 expect_close = 0;
208
209 for (i = 0; i != len; i++) {
210 char c;
211 if (get_user(c, data + i))
212 return -EFAULT;
213 if (c == 'V')
214 expect_close = 42;
215 }
216 }
217 bfin_wdt_keepalive();
218 }
219
220 return len;
221}
222
223/**
224 * bfin_wdt_ioctl - Query Device
Bryan Wu1e6d3202007-07-15 02:50:02 +0800225 * @file: file handle of device
226 * @cmd: watchdog command
227 * @arg: argument
228 *
229 * Query basic information from the device or ping it, as outlined by the
230 * watchdog API.
231 */
Alan Cox9a5f50d2008-05-19 14:06:30 +0100232static long bfin_wdt_ioctl(struct file *file,
233 unsigned int cmd, unsigned long arg)
Bryan Wu1e6d3202007-07-15 02:50:02 +0800234{
235 void __user *argp = (void __user *)arg;
236 int __user *p = argp;
237
238 stampit();
239
240 switch (cmd) {
Alan Cox9a5f50d2008-05-19 14:06:30 +0100241 case WDIOC_GETSUPPORT:
242 if (copy_to_user(argp, &bfin_wdt_info, sizeof(bfin_wdt_info)))
243 return -EFAULT;
244 else
Bryan Wu1e6d3202007-07-15 02:50:02 +0800245 return 0;
Alan Cox9a5f50d2008-05-19 14:06:30 +0100246 case WDIOC_GETSTATUS:
247 case WDIOC_GETBOOTSTATUS:
248 return put_user(!!(_bfin_swrst & SWRST_RESET_WDOG), p);
Alan Cox9a5f50d2008-05-19 14:06:30 +0100249 case WDIOC_SETOPTIONS: {
250 unsigned long flags;
251 int options, ret = -EINVAL;
Bryan Wu1e6d3202007-07-15 02:50:02 +0800252
Alan Cox9a5f50d2008-05-19 14:06:30 +0100253 if (get_user(options, p))
254 return -EFAULT;
Bryan Wu1e6d3202007-07-15 02:50:02 +0800255
Alan Cox9a5f50d2008-05-19 14:06:30 +0100256 spin_lock_irqsave(&bfin_wdt_spinlock, flags);
257 if (options & WDIOS_DISABLECARD) {
258 bfin_wdt_stop();
259 ret = 0;
Bryan Wu1e6d3202007-07-15 02:50:02 +0800260 }
Alan Cox9a5f50d2008-05-19 14:06:30 +0100261 if (options & WDIOS_ENABLECARD) {
262 bfin_wdt_start();
263 ret = 0;
Bryan Wu1e6d3202007-07-15 02:50:02 +0800264 }
Alan Cox9a5f50d2008-05-19 14:06:30 +0100265 spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
266 return ret;
267 }
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000268 case WDIOC_KEEPALIVE:
269 bfin_wdt_keepalive();
270 return 0;
271 case WDIOC_SETTIMEOUT: {
272 int new_timeout;
273
274 if (get_user(new_timeout, p))
275 return -EFAULT;
276 if (bfin_wdt_set_timeout(new_timeout))
277 return -EINVAL;
278 }
279 /* Fall */
280 case WDIOC_GETTIMEOUT:
281 return put_user(timeout, p);
Alan Cox9a5f50d2008-05-19 14:06:30 +0100282 default:
283 return -ENOTTY;
Bryan Wu1e6d3202007-07-15 02:50:02 +0800284 }
285}
286
Bryan Wu1e6d3202007-07-15 02:50:02 +0800287#ifdef CONFIG_PM
288static int state_before_suspend;
289
290/**
291 * bfin_wdt_suspend - suspend the watchdog
292 * @pdev: device being suspended
293 * @state: requested suspend state
294 *
295 * Remember if the watchdog was running and stop it.
296 * TODO: is this even right? Doesn't seem to be any
297 * standard in the watchdog world ...
298 */
299static int bfin_wdt_suspend(struct platform_device *pdev, pm_message_t state)
300{
301 stampit();
302
303 state_before_suspend = bfin_wdt_running();
304 bfin_wdt_stop();
305
306 return 0;
307}
308
309/**
310 * bfin_wdt_resume - resume the watchdog
311 * @pdev: device being resumed
312 *
313 * If the watchdog was running, turn it back on.
314 */
315static int bfin_wdt_resume(struct platform_device *pdev)
316{
317 stampit();
318
319 if (state_before_suspend) {
320 bfin_wdt_set_timeout(timeout);
321 bfin_wdt_start();
322 }
323
324 return 0;
325}
326#else
327# define bfin_wdt_suspend NULL
328# define bfin_wdt_resume NULL
329#endif
330
Jan Engelhardtb47a1662008-01-22 20:48:10 +0100331static const struct file_operations bfin_wdt_fops = {
Alan Cox9a5f50d2008-05-19 14:06:30 +0100332 .owner = THIS_MODULE,
333 .llseek = no_llseek,
Wim Van Sebroeck5f3b2752011-02-23 20:04:38 +0000334 .write = bfin_wdt_write,
Alan Cox9a5f50d2008-05-19 14:06:30 +0100335 .unlocked_ioctl = bfin_wdt_ioctl,
336 .open = bfin_wdt_open,
337 .release = bfin_wdt_release,
Bryan Wu1e6d3202007-07-15 02:50:02 +0800338};
339
340static struct miscdevice bfin_wdt_miscdev = {
341 .minor = WATCHDOG_MINOR,
342 .name = "watchdog",
343 .fops = &bfin_wdt_fops,
344};
345
Wim Van Sebroeck42747d72009-12-26 18:55:22 +0000346static const struct watchdog_info bfin_wdt_info = {
Bryan Wu1e6d3202007-07-15 02:50:02 +0800347 .identity = "Blackfin Watchdog",
348 .options = WDIOF_SETTIMEOUT |
Alan Cox9a5f50d2008-05-19 14:06:30 +0100349 WDIOF_KEEPALIVEPING |
350 WDIOF_MAGICCLOSE,
Bryan Wu1e6d3202007-07-15 02:50:02 +0800351};
352
Bryan Wu1e6d3202007-07-15 02:50:02 +0800353/**
Mike Frysinger93539b12008-03-27 11:53:32 -0700354 * bfin_wdt_probe - Initialize module
355 *
Wim Van Sebroeck168b5252009-12-26 19:13:00 +0000356 * Registers the misc device. Actual device
Mike Frysinger93539b12008-03-27 11:53:32 -0700357 * initialization is handled by bfin_wdt_open().
358 */
Bill Pemberton2d991a12012-11-19 13:21:41 -0500359static int bfin_wdt_probe(struct platform_device *pdev)
Mike Frysinger93539b12008-03-27 11:53:32 -0700360{
361 int ret;
362
Mike Frysinger93539b12008-03-27 11:53:32 -0700363 ret = misc_register(&bfin_wdt_miscdev);
364 if (ret) {
Joe Perches27c766a2012-02-15 15:06:19 -0800365 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
366 WATCHDOG_MINOR, ret);
Mike Frysinger93539b12008-03-27 11:53:32 -0700367 return ret;
368 }
369
Joe Perches27c766a2012-02-15 15:06:19 -0800370 pr_info("initialized: timeout=%d sec (nowayout=%d)\n",
371 timeout, nowayout);
Mike Frysinger93539b12008-03-27 11:53:32 -0700372
373 return 0;
374}
375
376/**
377 * bfin_wdt_remove - Initialize module
378 *
Wim Van Sebroeck168b5252009-12-26 19:13:00 +0000379 * Unregisters the misc device. Actual device
Mike Frysinger93539b12008-03-27 11:53:32 -0700380 * deinitialization is handled by bfin_wdt_close().
381 */
Bill Pemberton4b12b892012-11-19 13:26:24 -0500382static int bfin_wdt_remove(struct platform_device *pdev)
Mike Frysinger93539b12008-03-27 11:53:32 -0700383{
384 misc_deregister(&bfin_wdt_miscdev);
Mike Frysinger93539b12008-03-27 11:53:32 -0700385 return 0;
386}
387
Wim Van Sebroeck168b5252009-12-26 19:13:00 +0000388/**
389 * bfin_wdt_shutdown - Soft Shutdown Handler
390 *
391 * Handles the soft shutdown event.
392 */
393static void bfin_wdt_shutdown(struct platform_device *pdev)
394{
395 stampit();
396
397 bfin_wdt_stop();
398}
399
Mike Frysinger93539b12008-03-27 11:53:32 -0700400static struct platform_device *bfin_wdt_device;
401
402static struct platform_driver bfin_wdt_driver = {
403 .probe = bfin_wdt_probe,
Bill Pemberton82268712012-11-19 13:21:12 -0500404 .remove = bfin_wdt_remove,
Wim Van Sebroeck168b5252009-12-26 19:13:00 +0000405 .shutdown = bfin_wdt_shutdown,
Mike Frysinger93539b12008-03-27 11:53:32 -0700406 .suspend = bfin_wdt_suspend,
407 .resume = bfin_wdt_resume,
408 .driver = {
409 .name = WATCHDOG_NAME,
410 .owner = THIS_MODULE,
411 },
412};
413
414/**
Bryan Wu1e6d3202007-07-15 02:50:02 +0800415 * bfin_wdt_init - Initialize module
416 *
Mike Frysinger93539b12008-03-27 11:53:32 -0700417 * Checks the module params and registers the platform device & driver.
418 * Real work is in the platform probe function.
Bryan Wu1e6d3202007-07-15 02:50:02 +0800419 */
420static int __init bfin_wdt_init(void)
421{
422 int ret;
423
424 stampit();
425
426 /* Check that the timeout value is within range */
427 if (bfin_wdt_set_timeout(timeout))
428 return -EINVAL;
429
430 /* Since this is an on-chip device and needs no board-specific
431 * resources, we'll handle all the platform device stuff here.
432 */
Mike Frysinger93539b12008-03-27 11:53:32 -0700433 ret = platform_driver_register(&bfin_wdt_driver);
Bryan Wu1e6d3202007-07-15 02:50:02 +0800434 if (ret) {
Joe Perches27c766a2012-02-15 15:06:19 -0800435 pr_err("unable to register driver\n");
Bryan Wu1e6d3202007-07-15 02:50:02 +0800436 return ret;
437 }
438
Wim Van Sebroecka77dba72009-04-14 20:20:07 +0000439 bfin_wdt_device = platform_device_register_simple(WATCHDOG_NAME,
440 -1, NULL, 0);
Mike Frysinger93539b12008-03-27 11:53:32 -0700441 if (IS_ERR(bfin_wdt_device)) {
Joe Perches27c766a2012-02-15 15:06:19 -0800442 pr_err("unable to register device\n");
Mike Frysinger93539b12008-03-27 11:53:32 -0700443 platform_driver_unregister(&bfin_wdt_driver);
444 return PTR_ERR(bfin_wdt_device);
Bryan Wu1e6d3202007-07-15 02:50:02 +0800445 }
446
Bryan Wu1e6d3202007-07-15 02:50:02 +0800447 return 0;
448}
449
450/**
451 * bfin_wdt_exit - Deinitialize module
452 *
Mike Frysinger93539b12008-03-27 11:53:32 -0700453 * Back out the platform device & driver steps. Real work is in the
454 * platform remove function.
Bryan Wu1e6d3202007-07-15 02:50:02 +0800455 */
456static void __exit bfin_wdt_exit(void)
457{
Mike Frysinger93539b12008-03-27 11:53:32 -0700458 platform_device_unregister(bfin_wdt_device);
459 platform_driver_unregister(&bfin_wdt_driver);
Bryan Wu1e6d3202007-07-15 02:50:02 +0800460}
461
462module_init(bfin_wdt_init);
463module_exit(bfin_wdt_exit);
464
465MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <vapier@gentoo.org>");
466MODULE_DESCRIPTION("Blackfin Watchdog Device Driver");
467MODULE_LICENSE("GPL");
468MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
469
470module_param(timeout, uint, 0);
Alan Cox9a5f50d2008-05-19 14:06:30 +0100471MODULE_PARM_DESC(timeout,
472 "Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default="
473 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
Bryan Wu1e6d3202007-07-15 02:50:02 +0800474
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +0100475module_param(nowayout, bool, 0);
Alan Cox9a5f50d2008-05-19 14:06:30 +0100476MODULE_PARM_DESC(nowayout,
477 "Watchdog cannot be stopped once started (default="
478 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");