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 | |
70 | static int timeout = 1; |
71 | static int io = -1; |
72 | static int io_len = 2; /* for non plug and play */ |
73 | static unsigned long open_flag; |
74 | static char expect_close; |
75 | static DEFINE_SPINLOCK(sc1200wdt_lock); /* io port access serialisation */ |
76 | |
77 | #if defined CONFIG_PNP |
78 | static int isapnp = 1; |
79 | static struct pnp_dev *wdt_dev; |
80 | |
81 | module_param(isapnp, int, 0); |
82 | MODULE_PARM_DESC(isapnp, |
83 | "When set to 0 driver ISA PnP support will be disabled" ); |
84 | #endif |
85 | |
86 | module_param_hw(io, int, ioport, 0); |
87 | MODULE_PARM_DESC(io, "io port" ); |
88 | module_param(timeout, int, 0); |
89 | MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1" ); |
90 | |
91 | static bool nowayout = WATCHDOG_NOWAYOUT; |
92 | module_param(nowayout, bool, 0); |
93 | MODULE_PARM_DESC(nowayout, |
94 | "Watchdog cannot be stopped once started (default=" |
95 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")" ); |
96 | |
97 | |
98 | |
99 | /* Read from Data Register */ |
100 | static 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 | |
107 | static 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 */ |
115 | static 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 | |
122 | static 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 | |
131 | static void sc1200wdt_start(void) |
132 | { |
133 | unsigned char reg; |
134 | spin_lock(lock: &sc1200wdt_lock); |
135 | |
136 | __sc1200wdt_read_data(WDCF, data: ®); |
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 | |
146 | static 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. */ |
152 | static 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 | |
164 | static 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 | |
180 | static 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 | |
248 | static 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 | |
264 | static 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 | |
291 | static 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 | |
301 | static struct notifier_block sc1200wdt_notifier = { |
302 | .notifier_call = sc1200wdt_notify_sys, |
303 | }; |
304 | |
305 | static 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 | |
315 | static struct miscdevice sc1200wdt_miscdev = { |
316 | .minor = WATCHDOG_MINOR, |
317 | .name = "watchdog" , |
318 | .fops = &sc1200wdt_fops, |
319 | }; |
320 | |
321 | |
322 | static 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: ®); |
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 | |
341 | static 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 | |
347 | static 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 | |
367 | static 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 | |
375 | static 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 | |
385 | static 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 | |
438 | out_clean: |
439 | return ret; |
440 | |
441 | out_rbt: |
442 | unregister_reboot_notifier(&sc1200wdt_notifier); |
443 | |
444 | out_io: |
445 | release_region(io, io_len); |
446 | |
447 | out_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 | |
456 | static 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 | |
469 | module_init(sc1200wdt_init); |
470 | module_exit(sc1200wdt_exit); |
471 | |
472 | MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>" ); |
473 | MODULE_DESCRIPTION( |
474 | "Driver for National Semiconductor PC87307/PC97307 watchdog component" ); |
475 | MODULE_LICENSE("GPL" ); |
476 | |