drivers/watchdog/it87_wdt.c

   1 /*
   2  *      Watchdog Timer Driver
   3  *         for ITE IT87xx Environment Control - Low Pin Count Input / Output
   4  *
   5  *      (c) Copyright 2007  Oliver Schuster <olivers137@aol.com>
   6  *
   7  *      Based on softdog.c      by Alan Cox,
   8  *               83977f_wdt.c   by Jose Goncalves,
   9  *               it87.c         by Chris Gauthron, Jean Delvare
  10  *
  11  *      Data-sheets: Publicly available at the ITE website
  12  *                  http://www.ite.com.tw/
  13  *
  14  *      Support of the watchdog timers, which are available on
  15  *      IT8607, IT8620, IT8622, IT8625, IT8628, IT8655, IT8665, IT8686,
  16  *      IT8702, IT8712, IT8716, IT8718, IT8720, IT8721, IT8726, IT8728,
  17  *      and IT8783.
  18  *
  19  *      This program is free software; you can redistribute it and/or
  20  *      modify it under the terms of the GNU General Public License
  21  *      as published by the Free Software Foundation; either version
  22  *      2 of the License, or (at your option) any later version.
  23  *
  24  *      This program is distributed in the hope that it will be useful,
  25  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  26  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  27  *      GNU General Public License for more details.
  28  */
  29
  30 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  31
  32 #include <linux/init.h>
  33 #include <linux/io.h>
  34 #include <linux/kernel.h>
  35 #include <linux/module.h>
  36 #include <linux/moduleparam.h>
  37 #include <linux/types.h>
  38 #include <linux/watchdog.h>
  39
  40 #define WATCHDOG_NAME           "IT87 WDT"
  41
  42 /* Defaults for Module Parameter */
  43 #define DEFAULT_TIMEOUT         60
  44 #define DEFAULT_TESTMODE        0
  45 #define DEFAULT_NOWAYOUT        WATCHDOG_NOWAYOUT
  46
  47 /* IO Ports */
  48 #define REG             0x2e
  49 #define VAL             0x2f
  50
  51 /* Logical device Numbers LDN */
  52 #define GPIO            0x07
  53
  54 /* Configuration Registers and Functions */
  55 #define LDNREG          0x07
  56 #define CHIPID          0x20
  57 #define CHIPREV         0x22
  58
  59 /* Chip Id numbers */
  60 #define NO_DEV_ID       0xffff
  61 #define IT8607_ID       0x8607
  62 #define IT8620_ID       0x8620
  63 #define IT8622_ID       0x8622
  64 #define IT8625_ID       0x8625
  65 #define IT8628_ID       0x8628
  66 #define IT8655_ID       0x8655
  67 #define IT8665_ID       0x8665
  68 #define IT8686_ID       0x8686
  69 #define IT8702_ID       0x8702
  70 #define IT8705_ID       0x8705
  71 #define IT8712_ID       0x8712
  72 #define IT8716_ID       0x8716
  73 #define IT8718_ID       0x8718
  74 #define IT8720_ID       0x8720
  75 #define IT8721_ID       0x8721
  76 #define IT8726_ID       0x8726  /* the data sheet suggest wrongly 0x8716 */
  77 #define IT8728_ID       0x8728
  78 #define IT8783_ID       0x8783
  79
  80 /* GPIO Configuration Registers LDN=0x07 */
  81 #define WDTCTRL         0x71
  82 #define WDTCFG          0x72
  83 #define WDTVALLSB       0x73
  84 #define WDTVALMSB       0x74
  85
  86 /* GPIO Bits WDTCFG */
  87 #define WDT_TOV1        0x80
  88 #define WDT_KRST        0x40
  89 #define WDT_TOVE        0x20
  90 #define WDT_PWROK       0x10 /* not in it8721 */
  91 #define WDT_INT_MASK    0x0f
  92
  93 static unsigned int max_units, chip_type;
  94
  95 static unsigned int timeout = DEFAULT_TIMEOUT;
  96 static int testmode = DEFAULT_TESTMODE;
  97 static bool nowayout = DEFAULT_NOWAYOUT;
  98
  99 module_param(timeout, int, 0);
 100 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default="
 101                 __MODULE_STRING(DEFAULT_TIMEOUT));
 102 module_param(testmode, int, 0);
 103 MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default="
 104                 __MODULE_STRING(DEFAULT_TESTMODE));
 105 module_param(nowayout, bool, 0);
 106 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
 107                 __MODULE_STRING(WATCHDOG_NOWAYOUT));
 108
 109 /* Superio Chip */
 110
 111 static inline int superio_enter(void)
 112 {
 113         /*
 114          * Try to reserve REG and REG + 1 for exclusive access.
 115          */
 116         if (!request_muxed_region(REG, 2, WATCHDOG_NAME))
 117                 return -EBUSY;
 118
 119         outb(0x87, REG);
 120         outb(0x01, REG);
 121         outb(0x55, REG);
 122         outb(0x55, REG);
 123         return 0;
 124 }
 125
 126 static inline void superio_exit(void)
 127 {
 128         outb(0x02, REG);
 129         outb(0x02, VAL);
 130         release_region(REG, 2);
 131 }
 132
 133 static inline void superio_select(int ldn)
 134 {
 135         outb(LDNREG, REG);
 136         outb(ldn, VAL);
 137 }
 138
 139 static inline int superio_inb(int reg)
 140 {
 141         outb(reg, REG);
 142         return inb(VAL);
 143 }
 144
 145 static inline void superio_outb(int val, int reg)
 146 {
 147         outb(reg, REG);
 148         outb(val, VAL);
 149 }
 150
 151 static inline int superio_inw(int reg)
 152 {
 153         int val;
 154         outb(reg++, REG);
 155         val = inb(VAL) << 8;
 156         outb(reg, REG);
 157         val |= inb(VAL);
 158         return val;
 159 }
 160
 161 static inline void superio_outw(int val, int reg)
 162 {
 163         outb(reg++, REG);
 164         outb(val >> 8, VAL);
 165         outb(reg, REG);
 166         outb(val, VAL);
 167 }
 168
 169 /* Internal function, should be called after superio_select(GPIO) */
 170 static void _wdt_update_timeout(unsigned int t)
 171 {
 172         unsigned char cfg = WDT_KRST;
 173
 174         if (testmode)
 175                 cfg = 0;
 176
 177         if (t <= max_units)
 178                 cfg |= WDT_TOV1;
 179         else
 180                 t /= 60;
 181
 182         if (chip_type != IT8721_ID)
 183                 cfg |= WDT_PWROK;
 184
 185         superio_outb(cfg, WDTCFG);
 186         superio_outb(t, WDTVALLSB);
 187         if (max_units > 255)
 188                 superio_outb(t >> 8, WDTVALMSB);
 189 }
 190
 191 static int wdt_update_timeout(unsigned int t)
 192 {
 193         int ret;
 194
 195         ret = superio_enter();
 196         if (ret)
 197                 return ret;
 198
 199         superio_select(GPIO);
 200         _wdt_update_timeout(t);
 201         superio_exit();
 202
 203         return 0;
 204 }
 205
 206 static int wdt_round_time(int t)
 207 {
 208         t += 59;
 209         t -= t % 60;
 210         return t;
 211 }
 212
 213 /* watchdog timer handling */
 214
 215 static int wdt_start(struct watchdog_device *wdd)
 216 {
 217         return wdt_update_timeout(wdd->timeout);
 218 }
 219
 220 static int wdt_stop(struct watchdog_device *wdd)
 221 {
 222         return wdt_update_timeout(0);
 223 }
 224
 225 /**
 226  *      wdt_set_timeout - set a new timeout value with watchdog ioctl
 227  *      @t: timeout value in seconds
 228  *
 229  *      The hardware device has a 8 or 16 bit watchdog timer (depends on
 230  *      chip version) that can be configured to count seconds or minutes.
 231  *
 232  *      Used within WDIOC_SETTIMEOUT watchdog device ioctl.
 233  */
 234
 235 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
 236 {
 237         int ret = 0;
 238
 239         if (t > max_units)
 240                 t = wdt_round_time(t);
 241
 242         wdd->timeout = t;
 243
 244         if (watchdog_hw_running(wdd))
 245                 ret = wdt_update_timeout(t);
 246
 247         return ret;
 248 }
 249
 250 static const struct watchdog_info ident = {
 251         .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 252         .firmware_version = 1,
 253         .identity = WATCHDOG_NAME,
 254 };
 255
 256 static const struct watchdog_ops wdt_ops = {
 257         .owner = THIS_MODULE,
 258         .start = wdt_start,
 259         .stop = wdt_stop,
 260         .set_timeout = wdt_set_timeout,
 261 };
 262
 263 static struct watchdog_device wdt_dev = {
 264         .info = &ident,
 265         .ops = &wdt_ops,
 266         .min_timeout = 1,
 267 };
 268
 269 static int __init it87_wdt_init(void)
 270 {
 271         u8  chip_rev;
 272         int rc;
 273
 274         rc = superio_enter();
 275         if (rc)
 276                 return rc;
 277
 278         chip_type = superio_inw(CHIPID);
 279         chip_rev  = superio_inb(CHIPREV) & 0x0f;
 280         superio_exit();
 281
 282         switch (chip_type) {
 283         case IT8702_ID:
 284                 max_units = 255;
 285                 break;
 286         case IT8712_ID:
 287                 max_units = (chip_rev < 8) ? 255 : 65535;
 288                 break;
 289         case IT8716_ID:
 290         case IT8726_ID:
 291                 max_units = 65535;
 292                 break;
 293         case IT8607_ID:
 294         case IT8620_ID:
 295         case IT8622_ID:
 296         case IT8625_ID:
 297         case IT8628_ID:
 298         case IT8655_ID:
 299         case IT8665_ID:
 300         case IT8686_ID:
 301         case IT8718_ID:
 302         case IT8720_ID:
 303         case IT8721_ID:
 304         case IT8728_ID:
 305         case IT8783_ID:
 306                 max_units = 65535;
 307                 break;
 308         case IT8705_ID:
 309                 pr_err("Unsupported Chip found, Chip %04x Revision %02x\n",
 310                        chip_type, chip_rev);
 311                 return -ENODEV;
 312         case NO_DEV_ID:
 313                 pr_err("no device\n");
 314                 return -ENODEV;
 315         default:
 316                 pr_err("Unknown Chip found, Chip %04x Revision %04x\n",
 317                        chip_type, chip_rev);
 318                 return -ENODEV;
 319         }
 320
 321         rc = superio_enter();
 322         if (rc)
 323                 return rc;
 324
 325         superio_select(GPIO);
 326         superio_outb(WDT_TOV1, WDTCFG);
 327         superio_outb(0x00, WDTCTRL);
 328         superio_exit();
 329
 330         if (timeout < 1 || timeout > max_units * 60) {
 331                 timeout = DEFAULT_TIMEOUT;
 332                 pr_warn("Timeout value out of range, use default %d sec\n",
 333                         DEFAULT_TIMEOUT);
 334         }
 335
 336         if (timeout > max_units)
 337                 timeout = wdt_round_time(timeout);
 338
 339         wdt_dev.timeout = timeout;
 340         wdt_dev.max_timeout = max_units * 60;
 341
 342         watchdog_stop_on_reboot(&wdt_dev);
 343         rc = watchdog_register_device(&wdt_dev);
 344         if (rc) {
 345                 pr_err("Cannot register watchdog device (err=%d)\n", rc);
 346                 return rc;
 347         }
 348
 349         pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
 350                 chip_type, chip_rev, timeout, nowayout, testmode);
 351
 352         return 0;
 353 }
 354
 355 static void __exit it87_wdt_exit(void)
 356 {
 357         watchdog_unregister_device(&wdt_dev);
 358 }
 359
 360 module_init(it87_wdt_init);
 361 module_exit(it87_wdt_exit);
 362
 363 MODULE_AUTHOR("Oliver Schuster");
 364 MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
 365 MODULE_LICENSE("GPL");