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Linux/drivers/watchdog/i6300esb.c

  1 /*
  2  *      i6300esb:       Watchdog timer driver for Intel 6300ESB chipset
  3  *
  4  *      (c) Copyright 2004 Google Inc.
  5  *      (c) Copyright 2005 David Härdeman <david@2gen.com>
  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  *      based on i810-tco.c which is in turn based on softdog.c
 13  *
 14  *      The timer is implemented in the following I/O controller hubs:
 15  *      (See the intel documentation on http://developer.intel.com.)
 16  *      6300ESB chip : document number 300641-004
 17  *
 18  *  2004YYZZ Ross Biro
 19  *      Initial version 0.01
 20  *  2004YYZZ Ross Biro
 21  *      Version 0.02
 22  *  20050210 David Härdeman <david@2gen.com>
 23  *      Ported driver to kernel 2.6
 24  */
 25 
 26 /*
 27  *      Includes, defines, variables, module parameters, ...
 28  */
 29 
 30 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 31 
 32 #include <linux/module.h>
 33 #include <linux/types.h>
 34 #include <linux/kernel.h>
 35 #include <linux/fs.h>
 36 #include <linux/mm.h>
 37 #include <linux/miscdevice.h>
 38 #include <linux/watchdog.h>
 39 #include <linux/init.h>
 40 #include <linux/pci.h>
 41 #include <linux/ioport.h>
 42 #include <linux/uaccess.h>
 43 #include <linux/io.h>
 44 
 45 /* Module and version information */
 46 #define ESB_VERSION "0.05"
 47 #define ESB_MODULE_NAME "i6300ESB timer"
 48 #define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION
 49 
 50 /* PCI configuration registers */
 51 #define ESB_CONFIG_REG  0x60            /* Config register                   */
 52 #define ESB_LOCK_REG    0x68            /* WDT lock register                 */
 53 
 54 /* Memory mapped registers */
 55 #define ESB_TIMER1_REG (BASEADDR + 0x00)/* Timer1 value after each reset     */
 56 #define ESB_TIMER2_REG (BASEADDR + 0x04)/* Timer2 value after each reset     */
 57 #define ESB_GINTSR_REG (BASEADDR + 0x08)/* General Interrupt Status Register */
 58 #define ESB_RELOAD_REG (BASEADDR + 0x0c)/* Reload register                   */
 59 
 60 /* Lock register bits */
 61 #define ESB_WDT_FUNC    (0x01 << 2)   /* Watchdog functionality            */
 62 #define ESB_WDT_ENABLE  (0x01 << 1)   /* Enable WDT                        */
 63 #define ESB_WDT_LOCK    (0x01 << 0)   /* Lock (nowayout)                   */
 64 
 65 /* Config register bits */
 66 #define ESB_WDT_REBOOT  (0x01 << 5)   /* Enable reboot on timeout          */
 67 #define ESB_WDT_FREQ    (0x01 << 2)   /* Decrement frequency               */
 68 #define ESB_WDT_INTTYPE (0x03 << 0)   /* Interrupt type on timer1 timeout  */
 69 
 70 /* Reload register bits */
 71 #define ESB_WDT_TIMEOUT (0x01 << 9)    /* Watchdog timed out                */
 72 #define ESB_WDT_RELOAD  (0x01 << 8)    /* prevent timeout                   */
 73 
 74 /* Magic constants */
 75 #define ESB_UNLOCK1     0x80            /* Step 1 to unlock reset registers  */
 76 #define ESB_UNLOCK2     0x86            /* Step 2 to unlock reset registers  */
 77 
 78 /* internal variables */
 79 static void __iomem *BASEADDR;
 80 static DEFINE_SPINLOCK(esb_lock); /* Guards the hardware */
 81 static unsigned long timer_alive;
 82 static struct pci_dev *esb_pci;
 83 static unsigned short triggered; /* The status of the watchdog upon boot */
 84 static char esb_expect_close;
 85 
 86 /* We can only use 1 card due to the /dev/watchdog restriction */
 87 static int cards_found;
 88 
 89 /* module parameters */
 90 /* 30 sec default heartbeat (1 < heartbeat < 2*1023) */
 91 #define WATCHDOG_HEARTBEAT 30
 92 static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
 93 module_param(heartbeat, int, 0);
 94 MODULE_PARM_DESC(heartbeat,
 95                 "Watchdog heartbeat in seconds. (1<heartbeat<2046, default="
 96                                 __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
 97 
 98 static bool nowayout = WATCHDOG_NOWAYOUT;
 99 module_param(nowayout, bool, 0);
100 MODULE_PARM_DESC(nowayout,
101                 "Watchdog cannot be stopped once started (default="
102                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
103 
104 /*
105  * Some i6300ESB specific functions
106  */
107 
108 /*
109  * Prepare for reloading the timer by unlocking the proper registers.
110  * This is performed by first writing 0x80 followed by 0x86 to the
111  * reload register. After this the appropriate registers can be written
112  * to once before they need to be unlocked again.
113  */
114 static inline void esb_unlock_registers(void)
115 {
116         writew(ESB_UNLOCK1, ESB_RELOAD_REG);
117         writew(ESB_UNLOCK2, ESB_RELOAD_REG);
118 }
119 
120 static int esb_timer_start(void)
121 {
122         u8 val;
123 
124         spin_lock(&esb_lock);
125         esb_unlock_registers();
126         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
127         /* Enable or Enable + Lock? */
128         val = ESB_WDT_ENABLE | (nowayout ? ESB_WDT_LOCK : 0x00);
129         pci_write_config_byte(esb_pci, ESB_LOCK_REG, val);
130         spin_unlock(&esb_lock);
131         return 0;
132 }
133 
134 static int esb_timer_stop(void)
135 {
136         u8 val;
137 
138         spin_lock(&esb_lock);
139         /* First, reset timers as suggested by the docs */
140         esb_unlock_registers();
141         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
142         /* Then disable the WDT */
143         pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0);
144         pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val);
145         spin_unlock(&esb_lock);
146 
147         /* Returns 0 if the timer was disabled, non-zero otherwise */
148         return val & ESB_WDT_ENABLE;
149 }
150 
151 static void esb_timer_keepalive(void)
152 {
153         spin_lock(&esb_lock);
154         esb_unlock_registers();
155         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
156         /* FIXME: Do we need to flush anything here? */
157         spin_unlock(&esb_lock);
158 }
159 
160 static int esb_timer_set_heartbeat(int time)
161 {
162         u32 val;
163 
164         if (time < 0x1 || time > (2 * 0x03ff))
165                 return -EINVAL;
166 
167         spin_lock(&esb_lock);
168 
169         /* We shift by 9, so if we are passed a value of 1 sec,
170          * val will be 1 << 9 = 512, then write that to two
171          * timers => 2 * 512 = 1024 (which is decremented at 1KHz)
172          */
173         val = time << 9;
174 
175         /* Write timer 1 */
176         esb_unlock_registers();
177         writel(val, ESB_TIMER1_REG);
178 
179         /* Write timer 2 */
180         esb_unlock_registers();
181         writel(val, ESB_TIMER2_REG);
182 
183         /* Reload */
184         esb_unlock_registers();
185         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
186 
187         /* FIXME: Do we need to flush everything out? */
188 
189         /* Done */
190         heartbeat = time;
191         spin_unlock(&esb_lock);
192         return 0;
193 }
194 
195 /*
196  *      /dev/watchdog handling
197  */
198 
199 static int esb_open(struct inode *inode, struct file *file)
200 {
201         /* /dev/watchdog can only be opened once */
202         if (test_and_set_bit(0, &timer_alive))
203                 return -EBUSY;
204 
205         /* Reload and activate timer */
206         esb_timer_start();
207 
208         return nonseekable_open(inode, file);
209 }
210 
211 static int esb_release(struct inode *inode, struct file *file)
212 {
213         /* Shut off the timer. */
214         if (esb_expect_close == 42)
215                 esb_timer_stop();
216         else {
217                 pr_crit("Unexpected close, not stopping watchdog!\n");
218                 esb_timer_keepalive();
219         }
220         clear_bit(0, &timer_alive);
221         esb_expect_close = 0;
222         return 0;
223 }
224 
225 static ssize_t esb_write(struct file *file, const char __user *data,
226                           size_t len, loff_t *ppos)
227 {
228         /* See if we got the magic character 'V' and reload the timer */
229         if (len) {
230                 if (!nowayout) {
231                         size_t i;
232 
233                         /* note: just in case someone wrote the magic character
234                          * five months ago... */
235                         esb_expect_close = 0;
236 
237                         /* scan to see whether or not we got the
238                          * magic character */
239                         for (i = 0; i != len; i++) {
240                                 char c;
241                                 if (get_user(c, data + i))
242                                         return -EFAULT;
243                                 if (c == 'V')
244                                         esb_expect_close = 42;
245                         }
246                 }
247 
248                 /* someone wrote to us, we should reload the timer */
249                 esb_timer_keepalive();
250         }
251         return len;
252 }
253 
254 static long esb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
255 {
256         int new_options, retval = -EINVAL;
257         int new_heartbeat;
258         void __user *argp = (void __user *)arg;
259         int __user *p = argp;
260         static const struct watchdog_info ident = {
261                 .options =              WDIOF_SETTIMEOUT |
262                                         WDIOF_KEEPALIVEPING |
263                                         WDIOF_MAGICCLOSE,
264                 .firmware_version =     0,
265                 .identity =             ESB_MODULE_NAME,
266         };
267 
268         switch (cmd) {
269         case WDIOC_GETSUPPORT:
270                 return copy_to_user(argp, &ident,
271                                         sizeof(ident)) ? -EFAULT : 0;
272 
273         case WDIOC_GETSTATUS:
274                 return put_user(0, p);
275 
276         case WDIOC_GETBOOTSTATUS:
277                 return put_user(triggered, p);
278 
279         case WDIOC_SETOPTIONS:
280         {
281                 if (get_user(new_options, p))
282                         return -EFAULT;
283 
284                 if (new_options & WDIOS_DISABLECARD) {
285                         esb_timer_stop();
286                         retval = 0;
287                 }
288 
289                 if (new_options & WDIOS_ENABLECARD) {
290                         esb_timer_start();
291                         retval = 0;
292                 }
293                 return retval;
294         }
295         case WDIOC_KEEPALIVE:
296                 esb_timer_keepalive();
297                 return 0;
298 
299         case WDIOC_SETTIMEOUT:
300         {
301                 if (get_user(new_heartbeat, p))
302                         return -EFAULT;
303                 if (esb_timer_set_heartbeat(new_heartbeat))
304                         return -EINVAL;
305                 esb_timer_keepalive();
306                 /* Fall */
307         }
308         case WDIOC_GETTIMEOUT:
309                 return put_user(heartbeat, p);
310         default:
311                 return -ENOTTY;
312         }
313 }
314 
315 /*
316  *      Kernel Interfaces
317  */
318 
319 static const struct file_operations esb_fops = {
320         .owner = THIS_MODULE,
321         .llseek = no_llseek,
322         .write = esb_write,
323         .unlocked_ioctl = esb_ioctl,
324         .open = esb_open,
325         .release = esb_release,
326 };
327 
328 static struct miscdevice esb_miscdev = {
329         .minor = WATCHDOG_MINOR,
330         .name = "watchdog",
331         .fops = &esb_fops,
332 };
333 
334 /*
335  * Data for PCI driver interface
336  */
337 static const struct pci_device_id esb_pci_tbl[] = {
338         { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9), },
339         { 0, },                 /* End of list */
340 };
341 MODULE_DEVICE_TABLE(pci, esb_pci_tbl);
342 
343 /*
344  *      Init & exit routines
345  */
346 
347 static unsigned char esb_getdevice(struct pci_dev *pdev)
348 {
349         if (pci_enable_device(pdev)) {
350                 pr_err("failed to enable device\n");
351                 goto err_devput;
352         }
353 
354         if (pci_request_region(pdev, 0, ESB_MODULE_NAME)) {
355                 pr_err("failed to request region\n");
356                 goto err_disable;
357         }
358 
359         BASEADDR = pci_ioremap_bar(pdev, 0);
360         if (BASEADDR == NULL) {
361                 /* Something's wrong here, BASEADDR has to be set */
362                 pr_err("failed to get BASEADDR\n");
363                 goto err_release;
364         }
365 
366         /* Done */
367         esb_pci = pdev;
368         return 1;
369 
370 err_release:
371         pci_release_region(pdev, 0);
372 err_disable:
373         pci_disable_device(pdev);
374 err_devput:
375         return 0;
376 }
377 
378 static void esb_initdevice(void)
379 {
380         u8 val1;
381         u16 val2;
382 
383         /*
384          * Config register:
385          * Bit    5 : 0 = Enable WDT_OUTPUT
386          * Bit    2 : 0 = set the timer frequency to the PCI clock
387          * divided by 2^15 (approx 1KHz).
388          * Bits 1:0 : 11 = WDT_INT_TYPE Disabled.
389          * The watchdog has two timers, it can be setup so that the
390          * expiry of timer1 results in an interrupt and the expiry of
391          * timer2 results in a reboot. We set it to not generate
392          * any interrupts as there is not much we can do with it
393          * right now.
394          */
395         pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003);
396 
397         /* Check that the WDT isn't already locked */
398         pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1);
399         if (val1 & ESB_WDT_LOCK)
400                 pr_warn("nowayout already set\n");
401 
402         /* Set the timer to watchdog mode and disable it for now */
403         pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00);
404 
405         /* Check if the watchdog was previously triggered */
406         esb_unlock_registers();
407         val2 = readw(ESB_RELOAD_REG);
408         if (val2 & ESB_WDT_TIMEOUT)
409                 triggered = WDIOF_CARDRESET;
410 
411         /* Reset WDT_TIMEOUT flag and timers */
412         esb_unlock_registers();
413         writew((ESB_WDT_TIMEOUT | ESB_WDT_RELOAD), ESB_RELOAD_REG);
414 
415         /* And set the correct timeout value */
416         esb_timer_set_heartbeat(heartbeat);
417 }
418 
419 static int esb_probe(struct pci_dev *pdev,
420                 const struct pci_device_id *ent)
421 {
422         int ret;
423 
424         cards_found++;
425         if (cards_found == 1)
426                 pr_info("Intel 6300ESB WatchDog Timer Driver v%s\n",
427                         ESB_VERSION);
428 
429         if (cards_found > 1) {
430                 pr_err("This driver only supports 1 device\n");
431                 return -ENODEV;
432         }
433 
434         /* Check whether or not the hardware watchdog is there */
435         if (!esb_getdevice(pdev) || esb_pci == NULL)
436                 return -ENODEV;
437 
438         /* Check that the heartbeat value is within it's range;
439            if not reset to the default */
440         if (heartbeat < 0x1 || heartbeat > 2 * 0x03ff) {
441                 heartbeat = WATCHDOG_HEARTBEAT;
442                 pr_info("heartbeat value must be 1<heartbeat<2046, using %d\n",
443                         heartbeat);
444         }
445 
446         /* Initialize the watchdog and make sure it does not run */
447         esb_initdevice();
448 
449         /* Register the watchdog so that userspace has access to it */
450         ret = misc_register(&esb_miscdev);
451         if (ret != 0) {
452                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
453                        WATCHDOG_MINOR, ret);
454                 goto err_unmap;
455         }
456         pr_info("initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
457                 BASEADDR, heartbeat, nowayout);
458         return 0;
459 
460 err_unmap:
461         iounmap(BASEADDR);
462         pci_release_region(esb_pci, 0);
463         pci_disable_device(esb_pci);
464         esb_pci = NULL;
465         return ret;
466 }
467 
468 static void esb_remove(struct pci_dev *pdev)
469 {
470         /* Stop the timer before we leave */
471         if (!nowayout)
472                 esb_timer_stop();
473 
474         /* Deregister */
475         misc_deregister(&esb_miscdev);
476         iounmap(BASEADDR);
477         pci_release_region(esb_pci, 0);
478         pci_disable_device(esb_pci);
479         esb_pci = NULL;
480 }
481 
482 static void esb_shutdown(struct pci_dev *pdev)
483 {
484         esb_timer_stop();
485 }
486 
487 static struct pci_driver esb_driver = {
488         .name           = ESB_MODULE_NAME,
489         .id_table       = esb_pci_tbl,
490         .probe          = esb_probe,
491         .remove         = esb_remove,
492         .shutdown       = esb_shutdown,
493 };
494 
495 module_pci_driver(esb_driver);
496 
497 MODULE_AUTHOR("Ross Biro and David Härdeman");
498 MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
499 MODULE_LICENSE("GPL");
500 

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