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Linux/drivers/watchdog/sch311x_wdt.c

  1 /*
  2  *      sch311x_wdt.c - Driver for the SCH311x Super-I/O chips
  3  *                      integrated watchdog.
  4  *
  5  *      (c) Copyright 2008 Wim Van Sebroeck <wim@iguana.be>.
  6  *
  7  *      This program is free software; you can redistribute it and/or
  8  *      modify it under the terms of the GNU General Public License
  9  *      as published by the Free Software Foundation; either version
 10  *      2 of the License, or (at your option) any later version.
 11  *
 12  *      Neither Wim Van Sebroeck nor Iguana vzw. admit liability nor
 13  *      provide warranty for any of this software. This material is
 14  *      provided "AS-IS" and at no charge.
 15  */
 16 
 17 /*
 18  *      Includes, defines, variables, module parameters, ...
 19  */
 20 
 21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 22 
 23 /* Includes */
 24 #include <linux/module.h>               /* For module specific items */
 25 #include <linux/moduleparam.h>          /* For new moduleparam's */
 26 #include <linux/types.h>                /* For standard types (like size_t) */
 27 #include <linux/errno.h>                /* For the -ENODEV/... values */
 28 #include <linux/kernel.h>               /* For printk/... */
 29 #include <linux/miscdevice.h>           /* For struct miscdevice */
 30 #include <linux/watchdog.h>             /* For the watchdog specific items */
 31 #include <linux/init.h>                 /* For __init/__exit/... */
 32 #include <linux/fs.h>                   /* For file operations */
 33 #include <linux/platform_device.h>      /* For platform_driver framework */
 34 #include <linux/ioport.h>               /* For io-port access */
 35 #include <linux/spinlock.h>             /* For spin_lock/spin_unlock/... */
 36 #include <linux/uaccess.h>              /* For copy_to_user/put_user/... */
 37 #include <linux/io.h>                   /* For inb/outb/... */
 38 
 39 /* Module and version information */
 40 #define DRV_NAME        "sch311x_wdt"
 41 
 42 /* Runtime registers */
 43 #define GP60                    0x47
 44 #define WDT_TIME_OUT            0x65
 45 #define WDT_VAL                 0x66
 46 #define WDT_CFG                 0x67
 47 #define WDT_CTRL                0x68
 48 
 49 /* internal variables */
 50 static unsigned long sch311x_wdt_is_open;
 51 static char sch311x_wdt_expect_close;
 52 static struct platform_device *sch311x_wdt_pdev;
 53 
 54 static int sch311x_ioports[] = { 0x2e, 0x4e, 0x162e, 0x164e, 0x00 };
 55 
 56 static struct { /* The devices private data */
 57         /* the Runtime Register base address */
 58         unsigned short runtime_reg;
 59         /* The card's boot status */
 60         int boot_status;
 61         /* the lock for io operations */
 62         spinlock_t io_lock;
 63 } sch311x_wdt_data;
 64 
 65 /* Module load parameters */
 66 static unsigned short force_id;
 67 module_param(force_id, ushort, 0);
 68 MODULE_PARM_DESC(force_id, "Override the detected device ID");
 69 
 70 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
 71 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
 72 module_param(timeout, int, 0);
 73 MODULE_PARM_DESC(timeout,
 74         "Watchdog timeout in seconds. 1<= timeout <=15300, default="
 75                 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
 76 
 77 static bool nowayout = WATCHDOG_NOWAYOUT;
 78 module_param(nowayout, bool, 0);
 79 MODULE_PARM_DESC(nowayout,
 80         "Watchdog cannot be stopped once started (default="
 81                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 82 
 83 /*
 84  *      Super-IO functions
 85  */
 86 
 87 static inline void sch311x_sio_enter(int sio_config_port)
 88 {
 89         outb(0x55, sio_config_port);
 90 }
 91 
 92 static inline void sch311x_sio_exit(int sio_config_port)
 93 {
 94         outb(0xaa, sio_config_port);
 95 }
 96 
 97 static inline int sch311x_sio_inb(int sio_config_port, int reg)
 98 {
 99         outb(reg, sio_config_port);
100         return inb(sio_config_port + 1);
101 }
102 
103 static inline void sch311x_sio_outb(int sio_config_port, int reg, int val)
104 {
105         outb(reg, sio_config_port);
106         outb(val, sio_config_port + 1);
107 }
108 
109 /*
110  *      Watchdog Operations
111  */
112 
113 static void sch311x_wdt_set_timeout(int t)
114 {
115         unsigned char timeout_unit = 0x80;
116 
117         /* When new timeout is bigger then 255 seconds, we will use minutes */
118         if (t > 255) {
119                 timeout_unit = 0;
120                 t /= 60;
121         }
122 
123         /* -- Watchdog Timeout --
124          * Bit 0-6 (Reserved)
125          * Bit 7   WDT Time-out Value Units Select
126          *         (0 = Minutes, 1 = Seconds)
127          */
128         outb(timeout_unit, sch311x_wdt_data.runtime_reg + WDT_TIME_OUT);
129 
130         /* -- Watchdog Timer Time-out Value --
131          * Bit 0-7 Binary coded units (0=Disabled, 1..255)
132          */
133         outb(t, sch311x_wdt_data.runtime_reg + WDT_VAL);
134 }
135 
136 static void sch311x_wdt_start(void)
137 {
138         unsigned char t;
139 
140         spin_lock(&sch311x_wdt_data.io_lock);
141 
142         /* set watchdog's timeout */
143         sch311x_wdt_set_timeout(timeout);
144         /* enable the watchdog */
145         /* -- General Purpose I/O Bit 6.0 --
146          * Bit 0,   In/Out: 0 = Output, 1 = Input
147          * Bit 1,   Polarity: 0 = No Invert, 1 = Invert
148          * Bit 2-3, Function select: 00 = GPI/O, 01 = LED1, 11 = WDT,
149          *                           10 = Either Edge Triggered Intr.4
150          * Bit 4-6  (Reserved)
151          * Bit 7,   Output Type: 0 = Push Pull Bit, 1 = Open Drain
152          */
153         t = inb(sch311x_wdt_data.runtime_reg + GP60);
154         outb((t & ~0x0d) | 0x0c, sch311x_wdt_data.runtime_reg + GP60);
155 
156         spin_unlock(&sch311x_wdt_data.io_lock);
157 
158 }
159 
160 static void sch311x_wdt_stop(void)
161 {
162         unsigned char t;
163 
164         spin_lock(&sch311x_wdt_data.io_lock);
165 
166         /* stop the watchdog */
167         t = inb(sch311x_wdt_data.runtime_reg + GP60);
168         outb((t & ~0x0d) | 0x01, sch311x_wdt_data.runtime_reg + GP60);
169         /* disable timeout by setting it to 0 */
170         sch311x_wdt_set_timeout(0);
171 
172         spin_unlock(&sch311x_wdt_data.io_lock);
173 }
174 
175 static void sch311x_wdt_keepalive(void)
176 {
177         spin_lock(&sch311x_wdt_data.io_lock);
178         sch311x_wdt_set_timeout(timeout);
179         spin_unlock(&sch311x_wdt_data.io_lock);
180 }
181 
182 static int sch311x_wdt_set_heartbeat(int t)
183 {
184         if (t < 1 || t > (255*60))
185                 return -EINVAL;
186 
187         /* When new timeout is bigger then 255 seconds,
188          * we will round up to minutes (with a max of 255) */
189         if (t > 255)
190                 t = (((t - 1) / 60) + 1) * 60;
191 
192         timeout = t;
193         return 0;
194 }
195 
196 static void sch311x_wdt_get_status(int *status)
197 {
198         unsigned char new_status;
199 
200         *status = 0;
201 
202         spin_lock(&sch311x_wdt_data.io_lock);
203 
204         /* -- Watchdog timer control --
205          * Bit 0   Status Bit: 0 = Timer counting, 1 = Timeout occurred
206          * Bit 1   Reserved
207          * Bit 2   Force Timeout: 1 = Forces WD timeout event (self-cleaning)
208          * Bit 3   P20 Force Timeout enabled:
209          *          0 = P20 activity does not generate the WD timeout event
210          *          1 = P20 Allows rising edge of P20, from the keyboard
211          *              controller, to force the WD timeout event.
212          * Bit 4-7 Reserved
213          */
214         new_status = inb(sch311x_wdt_data.runtime_reg + WDT_CTRL);
215         if (new_status & 0x01)
216                 *status |= WDIOF_CARDRESET;
217 
218         spin_unlock(&sch311x_wdt_data.io_lock);
219 }
220 
221 /*
222  *      /dev/watchdog handling
223  */
224 
225 static ssize_t sch311x_wdt_write(struct file *file, const char __user *buf,
226                                                 size_t count, loff_t *ppos)
227 {
228         if (count) {
229                 if (!nowayout) {
230                         size_t i;
231 
232                         sch311x_wdt_expect_close = 0;
233 
234                         for (i = 0; i != count; i++) {
235                                 char c;
236                                 if (get_user(c, buf + i))
237                                         return -EFAULT;
238                                 if (c == 'V')
239                                         sch311x_wdt_expect_close = 42;
240                         }
241                 }
242                 sch311x_wdt_keepalive();
243         }
244         return count;
245 }
246 
247 static long sch311x_wdt_ioctl(struct file *file, unsigned int cmd,
248                                                         unsigned long arg)
249 {
250         int status;
251         int new_timeout;
252         void __user *argp = (void __user *)arg;
253         int __user *p = argp;
254         static const struct watchdog_info ident = {
255                 .options                = WDIOF_KEEPALIVEPING |
256                                           WDIOF_SETTIMEOUT |
257                                           WDIOF_MAGICCLOSE,
258                 .firmware_version       = 1,
259                 .identity               = DRV_NAME,
260         };
261 
262         switch (cmd) {
263         case WDIOC_GETSUPPORT:
264                 if (copy_to_user(argp, &ident, sizeof(ident)))
265                         return -EFAULT;
266                 break;
267 
268         case WDIOC_GETSTATUS:
269         {
270                 sch311x_wdt_get_status(&status);
271                 return put_user(status, p);
272         }
273         case WDIOC_GETBOOTSTATUS:
274                 return put_user(sch311x_wdt_data.boot_status, p);
275 
276         case WDIOC_SETOPTIONS:
277         {
278                 int options, retval = -EINVAL;
279 
280                 if (get_user(options, p))
281                         return -EFAULT;
282                 if (options & WDIOS_DISABLECARD) {
283                         sch311x_wdt_stop();
284                         retval = 0;
285                 }
286                 if (options & WDIOS_ENABLECARD) {
287                         sch311x_wdt_start();
288                         retval = 0;
289                 }
290                 return retval;
291         }
292         case WDIOC_KEEPALIVE:
293                 sch311x_wdt_keepalive();
294                 break;
295 
296         case WDIOC_SETTIMEOUT:
297                 if (get_user(new_timeout, p))
298                         return -EFAULT;
299                 if (sch311x_wdt_set_heartbeat(new_timeout))
300                         return -EINVAL;
301                 sch311x_wdt_keepalive();
302                 /* Fall */
303         case WDIOC_GETTIMEOUT:
304                 return put_user(timeout, p);
305         default:
306                 return -ENOTTY;
307         }
308         return 0;
309 }
310 
311 static int sch311x_wdt_open(struct inode *inode, struct file *file)
312 {
313         if (test_and_set_bit(0, &sch311x_wdt_is_open))
314                 return -EBUSY;
315         /*
316          *      Activate
317          */
318         sch311x_wdt_start();
319         return nonseekable_open(inode, file);
320 }
321 
322 static int sch311x_wdt_close(struct inode *inode, struct file *file)
323 {
324         if (sch311x_wdt_expect_close == 42) {
325                 sch311x_wdt_stop();
326         } else {
327                 pr_crit("Unexpected close, not stopping watchdog!\n");
328                 sch311x_wdt_keepalive();
329         }
330         clear_bit(0, &sch311x_wdt_is_open);
331         sch311x_wdt_expect_close = 0;
332         return 0;
333 }
334 
335 /*
336  *      Kernel Interfaces
337  */
338 
339 static const struct file_operations sch311x_wdt_fops = {
340         .owner          = THIS_MODULE,
341         .llseek         = no_llseek,
342         .write          = sch311x_wdt_write,
343         .unlocked_ioctl = sch311x_wdt_ioctl,
344         .open           = sch311x_wdt_open,
345         .release        = sch311x_wdt_close,
346 };
347 
348 static struct miscdevice sch311x_wdt_miscdev = {
349         .minor  = WATCHDOG_MINOR,
350         .name   = "watchdog",
351         .fops   = &sch311x_wdt_fops,
352 };
353 
354 /*
355  *      Init & exit routines
356  */
357 
358 static int sch311x_wdt_probe(struct platform_device *pdev)
359 {
360         struct device *dev = &pdev->dev;
361         int err;
362 
363         spin_lock_init(&sch311x_wdt_data.io_lock);
364 
365         if (!request_region(sch311x_wdt_data.runtime_reg + GP60, 1, DRV_NAME)) {
366                 dev_err(dev, "Failed to request region 0x%04x-0x%04x.\n",
367                         sch311x_wdt_data.runtime_reg + GP60,
368                         sch311x_wdt_data.runtime_reg + GP60);
369                 err = -EBUSY;
370                 goto exit;
371         }
372 
373         if (!request_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4,
374                                                                 DRV_NAME)) {
375                 dev_err(dev, "Failed to request region 0x%04x-0x%04x.\n",
376                         sch311x_wdt_data.runtime_reg + WDT_TIME_OUT,
377                         sch311x_wdt_data.runtime_reg + WDT_CTRL);
378                 err = -EBUSY;
379                 goto exit_release_region;
380         }
381 
382         /* Make sure that the watchdog is not running */
383         sch311x_wdt_stop();
384 
385         /* Disable keyboard and mouse interaction and interrupt */
386         /* -- Watchdog timer configuration --
387          * Bit 0   Reserved
388          * Bit 1   Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr.
389          * Bit 2   Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr
390          * Bit 3   Reserved
391          * Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled,
392          *            0001=IRQ1, 0010=(Invalid), 0011=IRQ3 to 1111=IRQ15)
393          */
394         outb(0, sch311x_wdt_data.runtime_reg + WDT_CFG);
395 
396         /* Check that the heartbeat value is within it's range ;
397          * if not reset to the default */
398         if (sch311x_wdt_set_heartbeat(timeout)) {
399                 sch311x_wdt_set_heartbeat(WATCHDOG_TIMEOUT);
400                 dev_info(dev, "timeout value must be 1<=x<=15300, using %d\n",
401                         timeout);
402         }
403 
404         /* Get status at boot */
405         sch311x_wdt_get_status(&sch311x_wdt_data.boot_status);
406 
407         sch311x_wdt_miscdev.parent = dev;
408 
409         err = misc_register(&sch311x_wdt_miscdev);
410         if (err != 0) {
411                 dev_err(dev, "cannot register miscdev on minor=%d (err=%d)\n",
412                                                         WATCHDOG_MINOR, err);
413                 goto exit_release_region2;
414         }
415 
416         dev_info(dev,
417                 "SMSC SCH311x WDT initialized. timeout=%d sec (nowayout=%d)\n",
418                 timeout, nowayout);
419 
420         return 0;
421 
422 exit_release_region2:
423         release_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4);
424 exit_release_region:
425         release_region(sch311x_wdt_data.runtime_reg + GP60, 1);
426         sch311x_wdt_data.runtime_reg = 0;
427 exit:
428         return err;
429 }
430 
431 static int sch311x_wdt_remove(struct platform_device *pdev)
432 {
433         /* Stop the timer before we leave */
434         if (!nowayout)
435                 sch311x_wdt_stop();
436 
437         /* Deregister */
438         misc_deregister(&sch311x_wdt_miscdev);
439         release_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4);
440         release_region(sch311x_wdt_data.runtime_reg + GP60, 1);
441         sch311x_wdt_data.runtime_reg = 0;
442         return 0;
443 }
444 
445 static void sch311x_wdt_shutdown(struct platform_device *dev)
446 {
447         /* Turn the WDT off if we have a soft shutdown */
448         sch311x_wdt_stop();
449 }
450 
451 static struct platform_driver sch311x_wdt_driver = {
452         .probe          = sch311x_wdt_probe,
453         .remove         = sch311x_wdt_remove,
454         .shutdown       = sch311x_wdt_shutdown,
455         .driver         = {
456                 .owner = THIS_MODULE,
457                 .name = DRV_NAME,
458         },
459 };
460 
461 static int __init sch311x_detect(int sio_config_port, unsigned short *addr)
462 {
463         int err = 0, reg;
464         unsigned short base_addr;
465         unsigned char dev_id;
466 
467         sch311x_sio_enter(sio_config_port);
468 
469         /* Check device ID. We currently know about:
470          * SCH3112 (0x7c), SCH3114 (0x7d), and SCH3116 (0x7f). */
471         reg = force_id ? force_id : sch311x_sio_inb(sio_config_port, 0x20);
472         if (!(reg == 0x7c || reg == 0x7d || reg == 0x7f)) {
473                 err = -ENODEV;
474                 goto exit;
475         }
476         dev_id = reg == 0x7c ? 2 : reg == 0x7d ? 4 : 6;
477 
478         /* Select logical device A (runtime registers) */
479         sch311x_sio_outb(sio_config_port, 0x07, 0x0a);
480 
481         /* Check if Logical Device Register is currently active */
482         if ((sch311x_sio_inb(sio_config_port, 0x30) & 0x01) == 0)
483                 pr_info("Seems that LDN 0x0a is not active...\n");
484 
485         /* Get the base address of the runtime registers */
486         base_addr = (sch311x_sio_inb(sio_config_port, 0x60) << 8) |
487                            sch311x_sio_inb(sio_config_port, 0x61);
488         if (!base_addr) {
489                 pr_err("Base address not set\n");
490                 err = -ENODEV;
491                 goto exit;
492         }
493         *addr = base_addr;
494 
495         pr_info("Found an SMSC SCH311%d chip at 0x%04x\n", dev_id, base_addr);
496 
497 exit:
498         sch311x_sio_exit(sio_config_port);
499         return err;
500 }
501 
502 static int __init sch311x_wdt_init(void)
503 {
504         int err, i, found = 0;
505         unsigned short addr = 0;
506 
507         for (i = 0; !found && sch311x_ioports[i]; i++)
508                 if (sch311x_detect(sch311x_ioports[i], &addr) == 0)
509                         found++;
510 
511         if (!found)
512                 return -ENODEV;
513 
514         sch311x_wdt_data.runtime_reg = addr;
515 
516         err = platform_driver_register(&sch311x_wdt_driver);
517         if (err)
518                 return err;
519 
520         sch311x_wdt_pdev = platform_device_register_simple(DRV_NAME, addr,
521                                                                 NULL, 0);
522 
523         if (IS_ERR(sch311x_wdt_pdev)) {
524                 err = PTR_ERR(sch311x_wdt_pdev);
525                 goto unreg_platform_driver;
526         }
527 
528         return 0;
529 
530 unreg_platform_driver:
531         platform_driver_unregister(&sch311x_wdt_driver);
532         return err;
533 }
534 
535 static void __exit sch311x_wdt_exit(void)
536 {
537         platform_device_unregister(sch311x_wdt_pdev);
538         platform_driver_unregister(&sch311x_wdt_driver);
539 }
540 
541 module_init(sch311x_wdt_init);
542 module_exit(sch311x_wdt_exit);
543 
544 MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>");
545 MODULE_DESCRIPTION("SMSC SCH311x WatchDog Timer Driver");
546 MODULE_LICENSE("GPL");
547 

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