drivers/watchdog/pnx833x_wdt.c

   1 /*
   2  *  PNX833x Hardware Watchdog Driver
   3  *  Copyright 2008 NXP Semiconductors
   4  *  Daniel Laird <daniel.j.laird@nxp.com>
   5  *  Andre McCurdy <andre.mccurdy@nxp.com>
   6  *
   7  *  Heavily based upon - IndyDog        0.3
   8  *  A Hardware Watchdog Device for SGI IP22
   9  *
  10  * (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>, All Rights Reserved.
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version
  15  * 2 of the License, or (at your option) any later version.
  16  *
  17  * based on softdog.c by Alan Cox <alan@redhat.com>
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/moduleparam.h>
  22 #include <linux/types.h>
  23 #include <linux/kernel.h>
  24 #include <linux/fs.h>
  25 #include <linux/mm.h>
  26 #include <linux/miscdevice.h>
  27 #include <linux/watchdog.h>
  28 #include <linux/notifier.h>
  29 #include <linux/reboot.h>
  30 #include <linux/init.h>
  31 #include <asm/mach-pnx833x/pnx833x.h>
  32
  33 #define PFX "pnx833x: "
  34 #define WATCHDOG_TIMEOUT 30             /* 30 sec Maximum timeout */
  35 #define WATCHDOG_COUNT_FREQUENCY 68000000U /* Watchdog counts at 68MHZ. */
  36 #define PNX_WATCHDOG_TIMEOUT    (WATCHDOG_TIMEOUT * WATCHDOG_COUNT_FREQUENCY)
  37 #define PNX_TIMEOUT_VALUE       2040000000U
  38
  39 /** CONFIG block */
  40 #define PNX833X_CONFIG                      (0x07000U)
  41 #define PNX833X_CONFIG_CPU_WATCHDOG         (0x54)
  42 #define PNX833X_CONFIG_CPU_WATCHDOG_COMPARE (0x58)
  43 #define PNX833X_CONFIG_CPU_COUNTERS_CONTROL (0x1c)
  44
  45 /** RESET block */
  46 #define PNX833X_RESET                       (0x08000U)
  47 #define PNX833X_RESET_CONFIG                (0x08)
  48
  49 static int pnx833x_wdt_alive;
  50
  51 /* Set default timeout in MHZ.*/
  52 static int pnx833x_wdt_timeout = PNX_WATCHDOG_TIMEOUT;
  53 module_param(pnx833x_wdt_timeout, int, 0);
  54 MODULE_PARM_DESC(timeout, "Watchdog timeout in Mhz. (68Mhz clock), default="
  55                         __MODULE_STRING(PNX_TIMEOUT_VALUE) "(30 seconds).");
  56
  57 static int nowayout = WATCHDOG_NOWAYOUT;
  58 module_param(nowayout, int, 0);
  59 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  60                                         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  61
  62 #define START_DEFAULT   1
  63 static int start_enabled = START_DEFAULT;
  64 module_param(start_enabled, int, 0);
  65 MODULE_PARM_DESC(start_enabled, "Watchdog is started on module insertion "
  66                                 "(default=" __MODULE_STRING(START_DEFAULT) ")");
  67
  68 static void pnx833x_wdt_start(void)
  69 {
  70         /* Enable watchdog causing reset. */
  71         PNX833X_REG(PNX833X_RESET + PNX833X_RESET_CONFIG) |= 0x1;
  72         /* Set timeout.*/
  73         PNX833X_REG(PNX833X_CONFIG +
  74                 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = pnx833x_wdt_timeout;
  75         /* Enable watchdog. */
  76         PNX833X_REG(PNX833X_CONFIG +
  77                                 PNX833X_CONFIG_CPU_COUNTERS_CONTROL) |= 0x1;
  78
  79         printk(KERN_INFO PFX "Started watchdog timer.\n");
  80 }
  81
  82 static void pnx833x_wdt_stop(void)
  83 {
  84         /* Disable watchdog causing reset. */
  85         PNX833X_REG(PNX833X_RESET + PNX833X_CONFIG) &= 0xFFFFFFFE;
  86         /* Disable watchdog.*/
  87         PNX833X_REG(PNX833X_CONFIG +
  88                         PNX833X_CONFIG_CPU_COUNTERS_CONTROL) &= 0xFFFFFFFE;
  89
  90         printk(KERN_INFO PFX "Stopped watchdog timer.\n");
  91 }
  92
  93 static void pnx833x_wdt_ping(void)
  94 {
  95         PNX833X_REG(PNX833X_CONFIG +
  96                 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = pnx833x_wdt_timeout;
  97 }
  98
  99 /*
 100  *      Allow only one person to hold it open
 101  */
 102 static int pnx833x_wdt_open(struct inode *inode, struct file *file)
 103 {
 104         if (test_and_set_bit(0, &pnx833x_wdt_alive))
 105                 return -EBUSY;
 106
 107         if (nowayout)
 108                 __module_get(THIS_MODULE);
 109
 110         /* Activate timer */
 111         if (!start_enabled)
 112                 pnx833x_wdt_start();
 113
 114         pnx833x_wdt_ping();
 115
 116         printk(KERN_INFO "Started watchdog timer.\n");
 117
 118         return nonseekable_open(inode, file);
 119 }
 120
 121 static int pnx833x_wdt_release(struct inode *inode, struct file *file)
 122 {
 123         /* Shut off the timer.
 124          * Lock it in if it's a module and we defined ...NOWAYOUT */
 125         if (!nowayout)
 126                 pnx833x_wdt_stop(); /* Turn the WDT off */
 127
 128         clear_bit(0, &pnx833x_wdt_alive);
 129         return 0;
 130 }
 131
 132 static ssize_t pnx833x_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
 133 {
 134         /* Refresh the timer. */
 135         if (len)
 136                 pnx833x_wdt_ping();
 137
 138         return len;
 139 }
 140
 141 static long pnx833x_wdt_ioctl(struct file *file, unsigned int cmd,
 142                                                         unsigned long arg)
 143 {
 144         int options, new_timeout = 0;
 145         uint32_t timeout, timeout_left = 0;
 146
 147         static const struct watchdog_info ident = {
 148                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
 149                 .firmware_version = 0,
 150                 .identity = "Hardware Watchdog for PNX833x",
 151         };
 152
 153         switch (cmd) {
 154         default:
 155                 return -ENOTTY;
 156
 157         case WDIOC_GETSUPPORT:
 158                 if (copy_to_user((struct watchdog_info *)arg,
 159                                  &ident, sizeof(ident)))
 160                         return -EFAULT;
 161                 return 0;
 162
 163         case WDIOC_GETSTATUS:
 164         case WDIOC_GETBOOTSTATUS:
 165                 return put_user(0, (int *)arg);
 166
 167         case WDIOC_SETOPTIONS:
 168                 if (get_user(options, (int *)arg))
 169                         return -EFAULT;
 170
 171                 if (options & WDIOS_DISABLECARD)
 172                         pnx833x_wdt_stop();
 173
 174                 if (options & WDIOS_ENABLECARD)
 175                         pnx833x_wdt_start();
 176
 177                 return 0;
 178
 179         case WDIOC_KEEPALIVE:
 180                 pnx833x_wdt_ping();
 181                 return 0;
 182
 183         case WDIOC_SETTIMEOUT:
 184         {
 185                 if (get_user(new_timeout, (int *)arg))
 186                         return -EFAULT;
 187
 188                 pnx833x_wdt_timeout = new_timeout;
 189                 PNX833X_REG(PNX833X_CONFIG +
 190                         PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = new_timeout;
 191                 return put_user(new_timeout, (int *)arg);
 192         }
 193
 194         case WDIOC_GETTIMEOUT:
 195                 timeout = PNX833X_REG(PNX833X_CONFIG +
 196                                         PNX833X_CONFIG_CPU_WATCHDOG_COMPARE);
 197                 return put_user(timeout, (int *)arg);
 198
 199         case WDIOC_GETTIMELEFT:
 200                 timeout_left = PNX833X_REG(PNX833X_CONFIG +
 201                                                 PNX833X_CONFIG_CPU_WATCHDOG);
 202                 return put_user(timeout_left, (int *)arg);
 203
 204         }
 205 }
 206
 207 static int pnx833x_wdt_notify_sys(struct notifier_block *this,
 208                                         unsigned long code, void *unused)
 209 {
 210         if (code == SYS_DOWN || code == SYS_HALT)
 211                 pnx833x_wdt_stop(); /* Turn the WDT off */
 212
 213         return NOTIFY_DONE;
 214 }
 215
 216 static const struct file_operations pnx833x_wdt_fops = {
 217         .owner          = THIS_MODULE,
 218         .llseek         = no_llseek,
 219         .write          = pnx833x_wdt_write,
 220         .unlocked_ioctl = pnx833x_wdt_ioctl,
 221         .open           = pnx833x_wdt_open,
 222         .release        = pnx833x_wdt_release,
 223 };
 224
 225 static struct miscdevice pnx833x_wdt_miscdev = {
 226         .minor          = WATCHDOG_MINOR,
 227         .name           = "watchdog",
 228         .fops           = &pnx833x_wdt_fops,
 229 };
 230
 231 static struct notifier_block pnx833x_wdt_notifier = {
 232         .notifier_call = pnx833x_wdt_notify_sys,
 233 };
 234
 235 static char banner[] __initdata =
 236         KERN_INFO PFX "Hardware Watchdog Timer for PNX833x: Version 0.1\n";
 237
 238 static int __init watchdog_init(void)
 239 {
 240         int ret, cause;
 241
 242         /* Lets check the reason for the reset.*/
 243         cause = PNX833X_REG(PNX833X_RESET);
 244         /*If bit 31 is set then watchdog was cause of reset.*/
 245         if (cause & 0x80000000) {
 246                 printk(KERN_INFO PFX "The system was previously reset due to "
 247                         "the watchdog firing - please investigate...\n");
 248         }
 249
 250         ret = register_reboot_notifier(&pnx833x_wdt_notifier);
 251         if (ret) {
 252                 printk(KERN_ERR PFX
 253                         "cannot register reboot notifier (err=%d)\n", ret);
 254                 return ret;
 255         }
 256
 257         ret = misc_register(&pnx833x_wdt_miscdev);
 258         if (ret) {
 259                 printk(KERN_ERR PFX
 260                         "cannot register miscdev on minor=%d (err=%d)\n",
 261                         WATCHDOG_MINOR, ret);
 262                 unregister_reboot_notifier(&pnx833x_wdt_notifier);
 263                 return ret;
 264         }
 265
 266         printk(banner);
 267         if (start_enabled)
 268                 pnx833x_wdt_start();
 269
 270         return 0;
 271 }
 272
 273 static void __exit watchdog_exit(void)
 274 {
 275         misc_deregister(&pnx833x_wdt_miscdev);
 276         unregister_reboot_notifier(&pnx833x_wdt_notifier);
 277 }
 278
 279 module_init(watchdog_init);
 280 module_exit(watchdog_exit);
 281
 282 MODULE_AUTHOR("Daniel Laird/Andre McCurdy");
 283 MODULE_DESCRIPTION("Hardware Watchdog Device for PNX833x");
 284 MODULE_LICENSE("GPL");
 285 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);