virtio-mem: simplify high-level unplug handling in Sub Block Mode
[linux-2.6-microblaze.git] / drivers / watchdog / sc1200wdt.c
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(index, PMIR);
104         *data = inb(PMDR);
105 }
106
107 static void sc1200wdt_read_data(unsigned char index, unsigned char *data)
108 {
109         spin_lock(&sc1200wdt_lock);
110         __sc1200wdt_read_data(index, data);
111         spin_unlock(&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(index, PMIR);
119         outb(data, PMDR);
120 }
121
122 static inline void sc1200wdt_write_data(unsigned char index,
123                                                 unsigned char data)
124 {
125         spin_lock(&sc1200wdt_lock);
126         __sc1200wdt_write_data(index, data);
127         spin_unlock(&sc1200wdt_lock);
128 }
129
130
131 static void sc1200wdt_start(void)
132 {
133         unsigned char reg;
134         spin_lock(&sc1200wdt_lock);
135
136         __sc1200wdt_read_data(WDCF, &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, reg);
140         /* set the timeout and get the ball rolling */
141         __sc1200wdt_write_data(WDTO, timeout);
142
143         spin_unlock(&sc1200wdt_lock);
144 }
145
146 static void sc1200wdt_stop(void)
147 {
148         sc1200wdt_write_data(WDTO, 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, &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(0, &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, 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(argp, &ident, 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, 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, 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, timeout);
255                 pr_crit("Unexpected close!, timeout = %d min(s)\n", timeout);
256         }
257         clear_bit(0, &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, 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, &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
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(wdt_dev, 0);
356         io_len = pnp_port_len(wdt_dev, 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(&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(&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(&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(&scl200wdt_pnp_driver);
451 #endif
452         goto out_clean;
453 }
454
455
456 static void __exit sc1200wdt_exit(void)
457 {
458         misc_deregister(&sc1200wdt_miscdev);
459         unregister_reboot_notifier(&sc1200wdt_notifier);
460
461 #if defined CONFIG_PNP
462         if (isapnp)
463                 pnp_unregister_driver(&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");