1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
4 * (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>,
5 * All Rights Reserved.
6 * Based on wdt.c and wdt977.c by Alan Cox and Woody Suwalski respectively.
7 *
8 * The author(s) of this software shall not be held liable for damages
9 * of any nature resulting due to the use of this software. This
10 * software is provided AS-IS with no warranties.
11 *
12 * Changelog:
13 * 20020220 Zwane Mwaikambo Code based on datasheet, no hardware.
14 * 20020221 Zwane Mwaikambo Cleanups as suggested by Jeff Garzik
15 * and Alan Cox.
16 * 20020222 Zwane Mwaikambo Added probing.
17 * 20020225 Zwane Mwaikambo Added ISAPNP support.
18 * 20020412 Rob Radez Broke out start/stop functions
19 * <rob@osinvestor.com> Return proper status instead of
20 * temperature warning
21 * Add WDIOC_GETBOOTSTATUS and
22 * WDIOC_SETOPTIONS ioctls
23 * Fix CONFIG_WATCHDOG_NOWAYOUT
24 * 20020530 Joel Becker Add Matt Domsch's nowayout module
25 * option
26 * 20030116 Adam Belay Updated to the latest pnp code
27 */
28
29#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
30
31#include <linux/module.h>
32#include <linux/moduleparam.h>
33#include <linux/miscdevice.h>
34#include <linux/watchdog.h>
35#include <linux/ioport.h>
36#include <linux/spinlock.h>
37#include <linux/notifier.h>
38#include <linux/reboot.h>
39#include <linux/init.h>
40#include <linux/pnp.h>
41#include <linux/fs.h>
42#include <linux/semaphore.h>
43#include <linux/io.h>
44#include <linux/uaccess.h>
45
46#define SC1200_MODULE_VER "build 20020303"
47#define SC1200_MODULE_NAME "sc1200wdt"
48
49#define MAX_TIMEOUT 255 /* 255 minutes */
50#define PMIR (io) /* Power Management Index Register */
51#define PMDR (io+1) /* Power Management Data Register */
52
53/* Data Register indexes */
54#define FER1 0x00 /* Function enable register 1 */
55#define FER2 0x01 /* Function enable register 2 */
56#define PMC1 0x02 /* Power Management Ctrl 1 */
57#define PMC2 0x03 /* Power Management Ctrl 2 */
58#define PMC3 0x04 /* Power Management Ctrl 3 */
59#define WDTO 0x05 /* Watchdog timeout register */
60#define WDCF 0x06 /* Watchdog config register */
61#define WDST 0x07 /* Watchdog status register */
62
63/* WDCF bitfields - which devices assert WDO */
64#define KBC_IRQ 0x01 /* Keyboard Controller */
65#define MSE_IRQ 0x02 /* Mouse */
66#define UART1_IRQ 0x03 /* Serial0 */
67#define UART2_IRQ 0x04 /* Serial1 */
68/* 5 -7 are reserved */
69
70static int timeout = 1;
71static int io = -1;
72static int io_len = 2; /* for non plug and play */
73static unsigned long open_flag;
74static char expect_close;
75static DEFINE_SPINLOCK(sc1200wdt_lock); /* io port access serialisation */
76
77#if defined CONFIG_PNP
78static int isapnp = 1;
79static struct pnp_dev *wdt_dev;
80
81module_param(isapnp, int, 0);
82MODULE_PARM_DESC(isapnp,
83 "When set to 0 driver ISA PnP support will be disabled");
84#endif
85
86module_param_hw(io, int, ioport, 0);
87MODULE_PARM_DESC(io, "io port");
88module_param(timeout, int, 0);
89MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1");
90
91static bool nowayout = WATCHDOG_NOWAYOUT;
92module_param(nowayout, bool, 0);
93MODULE_PARM_DESC(nowayout,
94 "Watchdog cannot be stopped once started (default="
95 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
96
97
98
99/* Read from Data Register */
100static inline void __sc1200wdt_read_data(unsigned char index,
101 unsigned char *data)
102{
103 outb_p(value: index, PMIR);
104 *data = inb(PMDR);
105}
106
107static void sc1200wdt_read_data(unsigned char index, unsigned char *data)
108{
109 spin_lock(lock: &sc1200wdt_lock);
110 __sc1200wdt_read_data(index, data);
111 spin_unlock(lock: &sc1200wdt_lock);
112}
113
114/* Write to Data Register */
115static inline void __sc1200wdt_write_data(unsigned char index,
116 unsigned char data)
117{
118 outb_p(value: index, PMIR);
119 outb(value: data, PMDR);
120}
121
122static inline void sc1200wdt_write_data(unsigned char index,
123 unsigned char data)
124{
125 spin_lock(lock: &sc1200wdt_lock);
126 __sc1200wdt_write_data(index, data);
127 spin_unlock(lock: &sc1200wdt_lock);
128}
129
130
131static void sc1200wdt_start(void)
132{
133 unsigned char reg;
134 spin_lock(lock: &sc1200wdt_lock);
135
136 __sc1200wdt_read_data(WDCF, data: &reg);
137 /* assert WDO when any of the following interrupts are triggered too */
138 reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ);
139 __sc1200wdt_write_data(WDCF, data: reg);
140 /* set the timeout and get the ball rolling */
141 __sc1200wdt_write_data(WDTO, data: timeout);
142
143 spin_unlock(lock: &sc1200wdt_lock);
144}
145
146static void sc1200wdt_stop(void)
147{
148 sc1200wdt_write_data(WDTO, data: 0);
149}
150
151/* This returns the status of the WDO signal, inactive high. */
152static inline int sc1200wdt_status(void)
153{
154 unsigned char ret;
155
156 sc1200wdt_read_data(WDST, data: &ret);
157 /* If the bit is inactive, the watchdog is enabled, so return
158 * KEEPALIVEPING which is a bit of a kludge because there's nothing
159 * else for enabled/disabled status
160 */
161 return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING;
162}
163
164static int sc1200wdt_open(struct inode *inode, struct file *file)
165{
166 /* allow one at a time */
167 if (test_and_set_bit(nr: 0, addr: &open_flag))
168 return -EBUSY;
169
170 if (timeout > MAX_TIMEOUT)
171 timeout = MAX_TIMEOUT;
172
173 sc1200wdt_start();
174 pr_info("Watchdog enabled, timeout = %d min(s)", timeout);
175
176 return stream_open(inode, filp: file);
177}
178
179
180static long sc1200wdt_ioctl(struct file *file, unsigned int cmd,
181 unsigned long arg)
182{
183 int new_timeout;
184 void __user *argp = (void __user *)arg;
185 int __user *p = argp;
186 static const struct watchdog_info ident = {
187 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
188 WDIOF_MAGICCLOSE,
189 .firmware_version = 0,
190 .identity = "PC87307/PC97307",
191 };
192
193 switch (cmd) {
194 case WDIOC_GETSUPPORT:
195 if (copy_to_user(to: argp, from: &ident, n: sizeof(ident)))
196 return -EFAULT;
197 return 0;
198
199 case WDIOC_GETSTATUS:
200 return put_user(sc1200wdt_status(), p);
201
202 case WDIOC_GETBOOTSTATUS:
203 return put_user(0, p);
204
205 case WDIOC_SETOPTIONS:
206 {
207 int options, retval = -EINVAL;
208
209 if (get_user(options, p))
210 return -EFAULT;
211
212 if (options & WDIOS_DISABLECARD) {
213 sc1200wdt_stop();
214 retval = 0;
215 }
216
217 if (options & WDIOS_ENABLECARD) {
218 sc1200wdt_start();
219 retval = 0;
220 }
221
222 return retval;
223 }
224 case WDIOC_KEEPALIVE:
225 sc1200wdt_write_data(WDTO, data: timeout);
226 return 0;
227
228 case WDIOC_SETTIMEOUT:
229 if (get_user(new_timeout, p))
230 return -EFAULT;
231 /* the API states this is given in secs */
232 new_timeout /= 60;
233 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
234 return -EINVAL;
235 timeout = new_timeout;
236 sc1200wdt_write_data(WDTO, data: timeout);
237 fallthrough; /* and return the new timeout */
238
239 case WDIOC_GETTIMEOUT:
240 return put_user(timeout * 60, p);
241
242 default:
243 return -ENOTTY;
244 }
245}
246
247
248static int sc1200wdt_release(struct inode *inode, struct file *file)
249{
250 if (expect_close == 42) {
251 sc1200wdt_stop();
252 pr_info("Watchdog disabled\n");
253 } else {
254 sc1200wdt_write_data(WDTO, data: timeout);
255 pr_crit("Unexpected close!, timeout = %d min(s)\n", timeout);
256 }
257 clear_bit(nr: 0, addr: &open_flag);
258 expect_close = 0;
259
260 return 0;
261}
262
263
264static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
265 size_t len, loff_t *ppos)
266{
267 if (len) {
268 if (!nowayout) {
269 size_t i;
270
271 expect_close = 0;
272
273 for (i = 0; i != len; i++) {
274 char c;
275
276 if (get_user(c, data + i))
277 return -EFAULT;
278 if (c == 'V')
279 expect_close = 42;
280 }
281 }
282
283 sc1200wdt_write_data(WDTO, data: timeout);
284 return len;
285 }
286
287 return 0;
288}
289
290
291static int sc1200wdt_notify_sys(struct notifier_block *this,
292 unsigned long code, void *unused)
293{
294 if (code == SYS_DOWN || code == SYS_HALT)
295 sc1200wdt_stop();
296
297 return NOTIFY_DONE;
298}
299
300
301static struct notifier_block sc1200wdt_notifier = {
302 .notifier_call = sc1200wdt_notify_sys,
303};
304
305static const struct file_operations sc1200wdt_fops = {
306 .owner = THIS_MODULE,
307 .llseek = no_llseek,
308 .write = sc1200wdt_write,
309 .unlocked_ioctl = sc1200wdt_ioctl,
310 .compat_ioctl = compat_ptr_ioctl,
311 .open = sc1200wdt_open,
312 .release = sc1200wdt_release,
313};
314
315static struct miscdevice sc1200wdt_miscdev = {
316 .minor = WATCHDOG_MINOR,
317 .name = "watchdog",
318 .fops = &sc1200wdt_fops,
319};
320
321
322static int __init sc1200wdt_probe(void)
323{
324 /* The probe works by reading the PMC3 register's default value of 0x0e
325 * there is one caveat, if the device disables the parallel port or any
326 * of the UARTs we won't be able to detect it.
327 * NB. This could be done with accuracy by reading the SID registers,
328 * but we don't have access to those io regions.
329 */
330
331 unsigned char reg;
332
333 sc1200wdt_read_data(PMC3, data: &reg);
334 reg &= 0x0f; /* we don't want the UART busy bits */
335 return (reg == 0x0e) ? 0 : -ENODEV;
336}
337
338
339#if defined CONFIG_PNP
340
341static const struct pnp_device_id scl200wdt_pnp_devices[] = {
342 /* National Semiconductor PC87307/PC97307 watchdog component */
343 {.id = "NSC0800", .driver_data = 0},
344 {.id = ""},
345};
346
347static int scl200wdt_pnp_probe(struct pnp_dev *dev,
348 const struct pnp_device_id *dev_id)
349{
350 /* this driver only supports one card at a time */
351 if (wdt_dev || !isapnp)
352 return -EBUSY;
353
354 wdt_dev = dev;
355 io = pnp_port_start(dev: wdt_dev, bar: 0);
356 io_len = pnp_port_len(dev: wdt_dev, bar: 0);
357
358 if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
359 pr_err("Unable to register IO port %#x\n", io);
360 return -EBUSY;
361 }
362
363 pr_info("PnP device found at io port %#x/%d\n", io, io_len);
364 return 0;
365}
366
367static void scl200wdt_pnp_remove(struct pnp_dev *dev)
368{
369 if (wdt_dev) {
370 release_region(io, io_len);
371 wdt_dev = NULL;
372 }
373}
374
375static struct pnp_driver scl200wdt_pnp_driver = {
376 .name = "scl200wdt",
377 .id_table = scl200wdt_pnp_devices,
378 .probe = scl200wdt_pnp_probe,
379 .remove = scl200wdt_pnp_remove,
380};
381
382#endif /* CONFIG_PNP */
383
384
385static int __init sc1200wdt_init(void)
386{
387 int ret;
388
389 pr_info("%s\n", SC1200_MODULE_VER);
390
391#if defined CONFIG_PNP
392 if (isapnp) {
393 ret = pnp_register_driver(drv: &scl200wdt_pnp_driver);
394 if (ret)
395 goto out_clean;
396 }
397#endif
398
399 if (io == -1) {
400 pr_err("io parameter must be specified\n");
401 ret = -EINVAL;
402 goto out_pnp;
403 }
404
405#if defined CONFIG_PNP
406 /* now that the user has specified an IO port and we haven't detected
407 * any devices, disable pnp support */
408 if (isapnp)
409 pnp_unregister_driver(drv: &scl200wdt_pnp_driver);
410 isapnp = 0;
411#endif
412
413 if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
414 pr_err("Unable to register IO port %#x\n", io);
415 ret = -EBUSY;
416 goto out_pnp;
417 }
418
419 ret = sc1200wdt_probe();
420 if (ret)
421 goto out_io;
422
423 ret = register_reboot_notifier(&sc1200wdt_notifier);
424 if (ret) {
425 pr_err("Unable to register reboot notifier err = %d\n", ret);
426 goto out_io;
427 }
428
429 ret = misc_register(misc: &sc1200wdt_miscdev);
430 if (ret) {
431 pr_err("Unable to register miscdev on minor %d\n",
432 WATCHDOG_MINOR);
433 goto out_rbt;
434 }
435
436 /* ret = 0 */
437
438out_clean:
439 return ret;
440
441out_rbt:
442 unregister_reboot_notifier(&sc1200wdt_notifier);
443
444out_io:
445 release_region(io, io_len);
446
447out_pnp:
448#if defined CONFIG_PNP
449 if (isapnp)
450 pnp_unregister_driver(drv: &scl200wdt_pnp_driver);
451#endif
452 goto out_clean;
453}
454
455
456static void __exit sc1200wdt_exit(void)
457{
458 misc_deregister(misc: &sc1200wdt_miscdev);
459 unregister_reboot_notifier(&sc1200wdt_notifier);
460
461#if defined CONFIG_PNP
462 if (isapnp)
463 pnp_unregister_driver(drv: &scl200wdt_pnp_driver);
464 else
465#endif
466 release_region(io, io_len);
467}
468
469module_init(sc1200wdt_init);
470module_exit(sc1200wdt_exit);
471
472MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
473MODULE_DESCRIPTION(
474 "Driver for National Semiconductor PC87307/PC97307 watchdog component");
475MODULE_LICENSE("GPL");
476

source code of linux/drivers/watchdog/sc1200wdt.c