2 * Watchdog driver for Technologic Systems TS-72xx based SBCs
3 * (TS-7200, TS-7250 and TS-7260). These boards have external
4 * glue logic CPLD chip, which includes programmable watchdog
7 * Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi>
9 * This driver is based on ep93xx_wdt and wm831x_wdt drivers.
11 * This file is licensed under the terms of the GNU General Public
12 * License version 2. This program is licensed "as is" without any
13 * warranty of any kind, whether express or implied.
18 #include <linux/module.h>
19 #include <linux/moduleparam.h>
20 #include <linux/miscdevice.h>
21 #include <linux/mutex.h>
22 #include <linux/platform_device.h>
23 #include <linux/watchdog.h>
24 #include <linux/uaccess.h>
26 #define TS72XX_WDT_FEED_VAL 0x05
27 #define TS72XX_WDT_DEFAULT_TIMEOUT 8
29 static int timeout
= TS72XX_WDT_DEFAULT_TIMEOUT
;
30 module_param(timeout
, int, 0);
31 MODULE_PARM_DESC(timeout
, "Watchdog timeout in seconds. "
32 "(1 <= timeout <= 8, default="
33 __MODULE_STRING(TS72XX_WDT_DEFAULT_TIMEOUT
)
36 static int nowayout
= WATCHDOG_NOWAYOUT
;
37 module_param(nowayout
, int, 0);
38 MODULE_PARM_DESC(nowayout
, "Disable watchdog shutdown on close");
41 * struct ts72xx_wdt - watchdog control structure
42 * @lock: lock that protects this structure
43 * @regval: watchdog timeout value suitable for control register
44 * @flags: flags controlling watchdog device state
45 * @control_reg: watchdog control register
46 * @feed_reg: watchdog feed register
47 * @pdev: back pointer to platform dev
53 #define TS72XX_WDT_BUSY_FLAG 1
54 #define TS72XX_WDT_EXPECT_CLOSE_FLAG 2
57 void __iomem
*control_reg
;
58 void __iomem
*feed_reg
;
60 struct platform_device
*pdev
;
63 struct platform_device
*ts72xx_wdt_pdev
;
66 * TS-72xx Watchdog supports following timeouts (value written
67 * to control register):
69 * -------------------------
70 * 0x00 watchdog disabled
79 * Timeouts below 1s are not very usable so we don't
82 * We provide two functions that convert between these:
83 * timeout_to_regval() and regval_to_timeout().
88 } ts72xx_wdt_map
[] = {
96 * timeout_to_regval() - converts given timeout to control register value
97 * @new_timeout: timeout in seconds to be converted
99 * Function converts given @new_timeout into valid value that can
100 * be programmed into watchdog control register. When conversion is
101 * not possible, function returns %-EINVAL.
103 static int timeout_to_regval(int new_timeout
)
107 /* first limit it to 1 - 8 seconds */
108 new_timeout
= clamp_val(new_timeout
, 1, 8);
110 for (i
= 0; i
< ARRAY_SIZE(ts72xx_wdt_map
); i
++) {
111 if (ts72xx_wdt_map
[i
].timeout
>= new_timeout
)
112 return ts72xx_wdt_map
[i
].regval
;
119 * regval_to_timeout() - converts control register value to timeout
120 * @regval: control register value to be converted
122 * Function converts given @regval to timeout in seconds (1, 2, 4 or 8).
123 * If @regval cannot be converted, function returns %-EINVAL.
125 static int regval_to_timeout(int regval
)
129 for (i
= 0; i
< ARRAY_SIZE(ts72xx_wdt_map
); i
++) {
130 if (ts72xx_wdt_map
[i
].regval
== regval
)
131 return ts72xx_wdt_map
[i
].timeout
;
138 * ts72xx_wdt_kick() - kick the watchdog
139 * @wdt: watchdog to be kicked
141 * Called with @wdt->lock held.
143 static inline void ts72xx_wdt_kick(struct ts72xx_wdt
*wdt
)
145 __raw_writeb(TS72XX_WDT_FEED_VAL
, wdt
->feed_reg
);
149 * ts72xx_wdt_start() - starts the watchdog timer
150 * @wdt: watchdog to be started
152 * This function programs timeout to watchdog timer
155 * Called with @wdt->lock held.
157 static void ts72xx_wdt_start(struct ts72xx_wdt
*wdt
)
160 * To program the wdt, it first must be "fed" and
161 * only after that (within 30 usecs) the configuration
164 ts72xx_wdt_kick(wdt
);
165 __raw_writeb((u8
)wdt
->regval
, wdt
->control_reg
);
169 * ts72xx_wdt_stop() - stops the watchdog timer
170 * @wdt: watchdog to be stopped
172 * Called with @wdt->lock held.
174 static void ts72xx_wdt_stop(struct ts72xx_wdt
*wdt
)
176 ts72xx_wdt_kick(wdt
);
177 __raw_writeb(0, wdt
->control_reg
);
180 static int ts72xx_wdt_open(struct inode
*inode
, struct file
*file
)
182 struct ts72xx_wdt
*wdt
= platform_get_drvdata(ts72xx_wdt_pdev
);
186 * Try to convert default timeout to valid register
189 regval
= timeout_to_regval(timeout
);
191 dev_err(&wdt
->pdev
->dev
,
192 "failed to convert timeout (%d) to register value\n",
197 if (mutex_lock_interruptible(&wdt
->lock
))
200 if ((wdt
->flags
& TS72XX_WDT_BUSY_FLAG
) != 0) {
201 mutex_unlock(&wdt
->lock
);
205 wdt
->flags
= TS72XX_WDT_BUSY_FLAG
;
206 wdt
->regval
= regval
;
207 file
->private_data
= wdt
;
209 ts72xx_wdt_start(wdt
);
211 mutex_unlock(&wdt
->lock
);
212 return nonseekable_open(inode
, file
);
215 static int ts72xx_wdt_release(struct inode
*inode
, struct file
*file
)
217 struct ts72xx_wdt
*wdt
= file
->private_data
;
219 if (mutex_lock_interruptible(&wdt
->lock
))
222 if ((wdt
->flags
& TS72XX_WDT_EXPECT_CLOSE_FLAG
) != 0) {
223 ts72xx_wdt_stop(wdt
);
225 dev_warn(&wdt
->pdev
->dev
,
226 "TS-72XX WDT device closed unexpectly. "
227 "Watchdog timer will not stop!\n");
229 * Kick it one more time, to give userland some time
230 * to recover (for example, respawning the kicker
233 ts72xx_wdt_kick(wdt
);
238 mutex_unlock(&wdt
->lock
);
242 static ssize_t
ts72xx_wdt_write(struct file
*file
,
243 const char __user
*data
,
247 struct ts72xx_wdt
*wdt
= file
->private_data
;
252 if (mutex_lock_interruptible(&wdt
->lock
))
255 ts72xx_wdt_kick(wdt
);
258 * Support for magic character closing. User process
259 * writes 'V' into the device, just before it is closed.
260 * This means that we know that the wdt timer can be
261 * stopped after user closes the device.
266 for (i
= 0; i
< len
; i
++) {
269 /* In case it was set long ago */
270 wdt
->flags
&= ~TS72XX_WDT_EXPECT_CLOSE_FLAG
;
272 if (get_user(c
, data
+ i
)) {
273 mutex_unlock(&wdt
->lock
);
277 wdt
->flags
|= TS72XX_WDT_EXPECT_CLOSE_FLAG
;
283 mutex_unlock(&wdt
->lock
);
287 static const struct watchdog_info winfo
= {
288 .options
= WDIOF_KEEPALIVEPING
| WDIOF_SETTIMEOUT
|
290 .firmware_version
= 1,
291 .identity
= "TS-72XX WDT",
294 static long ts72xx_wdt_ioctl(struct file
*file
, unsigned int cmd
,
297 struct ts72xx_wdt
*wdt
= file
->private_data
;
298 void __user
*argp
= (void __user
*)arg
;
299 int __user
*p
= (int __user
*)argp
;
302 if (mutex_lock_interruptible(&wdt
->lock
))
306 case WDIOC_GETSUPPORT
:
307 error
= copy_to_user(argp
, &winfo
, sizeof(winfo
));
310 case WDIOC_GETSTATUS
:
311 case WDIOC_GETBOOTSTATUS
:
312 return put_user(0, p
);
314 case WDIOC_KEEPALIVE
:
315 ts72xx_wdt_kick(wdt
);
318 case WDIOC_SETOPTIONS
: {
321 if (get_user(options
, p
)) {
328 if ((options
& WDIOS_DISABLECARD
) != 0) {
329 ts72xx_wdt_stop(wdt
);
332 if ((options
& WDIOS_ENABLECARD
) != 0) {
333 ts72xx_wdt_start(wdt
);
340 case WDIOC_SETTIMEOUT
: {
343 if (get_user(new_timeout
, p
)) {
348 regval
= timeout_to_regval(new_timeout
);
352 ts72xx_wdt_stop(wdt
);
353 wdt
->regval
= regval
;
354 ts72xx_wdt_start(wdt
);
363 case WDIOC_GETTIMEOUT
:
364 if (put_user(regval_to_timeout(wdt
->regval
), p
))
373 mutex_unlock(&wdt
->lock
);
377 static const struct file_operations ts72xx_wdt_fops
= {
378 .owner
= THIS_MODULE
,
380 .open
= ts72xx_wdt_open
,
381 .release
= ts72xx_wdt_release
,
382 .write
= ts72xx_wdt_write
,
383 .unlocked_ioctl
= ts72xx_wdt_ioctl
,
386 static struct miscdevice ts72xx_wdt_miscdev
= {
387 .minor
= WATCHDOG_MINOR
,
389 .fops
= &ts72xx_wdt_fops
,
392 static __devinit
int ts72xx_wdt_probe(struct platform_device
*pdev
)
394 struct ts72xx_wdt
*wdt
;
395 struct resource
*r1
, *r2
;
398 wdt
= kzalloc(sizeof(struct ts72xx_wdt
), GFP_KERNEL
);
400 dev_err(&pdev
->dev
, "failed to allocate memory\n");
404 r1
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
406 dev_err(&pdev
->dev
, "failed to get memory resource\n");
411 r1
= request_mem_region(r1
->start
, resource_size(r1
), pdev
->name
);
413 dev_err(&pdev
->dev
, "cannot request memory region\n");
418 wdt
->control_reg
= ioremap(r1
->start
, resource_size(r1
));
419 if (!wdt
->control_reg
) {
420 dev_err(&pdev
->dev
, "failed to map memory\n");
422 goto fail_free_control
;
425 r2
= platform_get_resource(pdev
, IORESOURCE_MEM
, 1);
427 dev_err(&pdev
->dev
, "failed to get memory resource\n");
429 goto fail_unmap_control
;
432 r2
= request_mem_region(r2
->start
, resource_size(r2
), pdev
->name
);
434 dev_err(&pdev
->dev
, "cannot request memory region\n");
436 goto fail_unmap_control
;
439 wdt
->feed_reg
= ioremap(r2
->start
, resource_size(r2
));
440 if (!wdt
->feed_reg
) {
441 dev_err(&pdev
->dev
, "failed to map memory\n");
446 platform_set_drvdata(pdev
, wdt
);
447 ts72xx_wdt_pdev
= pdev
;
449 mutex_init(&wdt
->lock
);
451 error
= misc_register(&ts72xx_wdt_miscdev
);
453 dev_err(&pdev
->dev
, "failed to register miscdev\n");
454 goto fail_unmap_feed
;
457 dev_info(&pdev
->dev
, "TS-72xx Watchdog driver\n");
462 platform_set_drvdata(pdev
, NULL
);
463 iounmap(wdt
->feed_reg
);
465 release_mem_region(r2
->start
, resource_size(r2
));
467 iounmap(wdt
->control_reg
);
469 release_mem_region(r1
->start
, resource_size(r1
));
475 static __devexit
int ts72xx_wdt_remove(struct platform_device
*pdev
)
477 struct ts72xx_wdt
*wdt
= platform_get_drvdata(pdev
);
478 struct resource
*res
;
481 error
= misc_deregister(&ts72xx_wdt_miscdev
);
482 platform_set_drvdata(pdev
, NULL
);
484 iounmap(wdt
->feed_reg
);
485 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 1);
486 release_mem_region(res
->start
, resource_size(res
));
488 iounmap(wdt
->control_reg
);
489 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
490 release_mem_region(res
->start
, resource_size(res
));
496 static struct platform_driver ts72xx_wdt_driver
= {
497 .probe
= ts72xx_wdt_probe
,
498 .remove
= __devexit_p(ts72xx_wdt_remove
),
500 .name
= "ts72xx-wdt",
501 .owner
= THIS_MODULE
,
505 static __init
int ts72xx_wdt_init(void)
507 return platform_driver_register(&ts72xx_wdt_driver
);
509 module_init(ts72xx_wdt_init
);
511 static __exit
void ts72xx_wdt_exit(void)
513 platform_driver_unregister(&ts72xx_wdt_driver
);
515 module_exit(ts72xx_wdt_exit
);
517 MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
518 MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
519 MODULE_LICENSE("GPL");
520 MODULE_ALIAS("platform:ts72xx-wdt");