drivers/watchdog/it87_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      Watchdog Timer Driver
   4  *         for ITE IT87xx Environment Control - Low Pin Count Input / Output
   5  *
   6  *      (c) Copyright 2007  Oliver Schuster <olivers137@aol.com>
   7  *
   8  *      Based on softdog.c      by Alan Cox,
   9  *               83977f_wdt.c   by Jose Goncalves,
  10  *               it87.c         by Chris Gauthron, Jean Delvare
  11  *
  12  *      Data-sheets: Publicly available at the ITE website
  13  *                  http://www.ite.com.tw/
  14  *
  15  *      Support of the watchdog timers, which are available on
  16  *      IT8607, IT8620, IT8622, IT8625, IT8628, IT8655, IT8665, IT8686,
  17  *      IT8702, IT8712, IT8716, IT8718, IT8720, IT8721, IT8726, IT8728,
  18  *      IT8772, IT8783 and IT8784.
  19  */
  20
  21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  22
  23 #include <linux/init.h>
  24 #include <linux/io.h>
  25 #include <linux/kernel.h>
  26 #include <linux/module.h>
  27 #include <linux/moduleparam.h>
  28 #include <linux/types.h>
  29 #include <linux/watchdog.h>
  30
  31 #define WATCHDOG_NAME           "IT87 WDT"
  32
  33 /* Defaults for Module Parameter */
  34 #define DEFAULT_TIMEOUT         60
  35 #define DEFAULT_TESTMODE        0
  36 #define DEFAULT_NOWAYOUT        WATCHDOG_NOWAYOUT
  37
  38 /* IO Ports */
  39 #define REG             0x2e
  40 #define VAL             0x2f
  41
  42 /* Logical device Numbers LDN */
  43 #define GPIO            0x07
  44
  45 /* Configuration Registers and Functions */
  46 #define LDNREG          0x07
  47 #define CHIPID          0x20
  48 #define CHIPREV         0x22
  49
  50 /* Chip Id numbers */
  51 #define NO_DEV_ID       0xffff
  52 #define IT8607_ID       0x8607
  53 #define IT8620_ID       0x8620
  54 #define IT8622_ID       0x8622
  55 #define IT8625_ID       0x8625
  56 #define IT8628_ID       0x8628
  57 #define IT8655_ID       0x8655
  58 #define IT8665_ID       0x8665
  59 #define IT8686_ID       0x8686
  60 #define IT8702_ID       0x8702
  61 #define IT8705_ID       0x8705
  62 #define IT8712_ID       0x8712
  63 #define IT8716_ID       0x8716
  64 #define IT8718_ID       0x8718
  65 #define IT8720_ID       0x8720
  66 #define IT8721_ID       0x8721
  67 #define IT8726_ID       0x8726  /* the data sheet suggest wrongly 0x8716 */
  68 #define IT8728_ID       0x8728
  69 #define IT8772_ID       0x8772
  70 #define IT8783_ID       0x8783
  71 #define IT8784_ID       0x8784
  72 #define IT8786_ID       0x8786
  73
  74 /* GPIO Configuration Registers LDN=0x07 */
  75 #define WDTCTRL         0x71
  76 #define WDTCFG          0x72
  77 #define WDTVALLSB       0x73
  78 #define WDTVALMSB       0x74
  79
  80 /* GPIO Bits WDTCFG */
  81 #define WDT_TOV1        0x80
  82 #define WDT_KRST        0x40
  83 #define WDT_TOVE        0x20
  84 #define WDT_PWROK       0x10 /* not in it8721 */
  85 #define WDT_INT_MASK    0x0f
  86
  87 static unsigned int max_units, chip_type;
  88
  89 static unsigned int timeout = DEFAULT_TIMEOUT;
  90 static int testmode = DEFAULT_TESTMODE;
  91 static bool nowayout = DEFAULT_NOWAYOUT;
  92
  93 module_param(timeout, int, 0);
  94 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default="
  95                 __MODULE_STRING(DEFAULT_TIMEOUT));
  96 module_param(testmode, int, 0);
  97 MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default="
  98                 __MODULE_STRING(DEFAULT_TESTMODE));
  99 module_param(nowayout, bool, 0);
 100 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
 101                 __MODULE_STRING(WATCHDOG_NOWAYOUT));
 102
 103 /* Superio Chip */
 104
 105 static inline int superio_enter(void)
 106 {
 107         /*
 108          * Try to reserve REG and REG + 1 for exclusive access.
 109          */
 110         if (!request_muxed_region(REG, 2, WATCHDOG_NAME))
 111                 return -EBUSY;
 112
 113         outb(0x87, REG);
 114         outb(0x01, REG);
 115         outb(0x55, REG);
 116         outb(0x55, REG);
 117         return 0;
 118 }
 119
 120 static inline void superio_exit(void)
 121 {
 122         outb(0x02, REG);
 123         outb(0x02, VAL);
 124         release_region(REG, 2);
 125 }
 126
 127 static inline void superio_select(int ldn)
 128 {
 129         outb(LDNREG, REG);
 130         outb(ldn, VAL);
 131 }
 132
 133 static inline int superio_inb(int reg)
 134 {
 135         outb(reg, REG);
 136         return inb(VAL);
 137 }
 138
 139 static inline void superio_outb(int val, int reg)
 140 {
 141         outb(reg, REG);
 142         outb(val, VAL);
 143 }
 144
 145 static inline int superio_inw(int reg)
 146 {
 147         int val;
 148         outb(reg++, REG);
 149         val = inb(VAL) << 8;
 150         outb(reg, REG);
 151         val |= inb(VAL);
 152         return val;
 153 }
 154
 155 static inline void superio_outw(int val, int reg)
 156 {
 157         outb(reg++, REG);
 158         outb(val >> 8, VAL);
 159         outb(reg, REG);
 160         outb(val, VAL);
 161 }
 162
 163 /* Internal function, should be called after superio_select(GPIO) */
 164 static void _wdt_update_timeout(unsigned int t)
 165 {
 166         unsigned char cfg = WDT_KRST;
 167
 168         if (testmode)
 169                 cfg = 0;
 170
 171         if (t <= max_units)
 172                 cfg |= WDT_TOV1;
 173         else
 174                 t /= 60;
 175
 176         if (chip_type != IT8721_ID)
 177                 cfg |= WDT_PWROK;
 178
 179         superio_outb(cfg, WDTCFG);
 180         superio_outb(t, WDTVALLSB);
 181         if (max_units > 255)
 182                 superio_outb(t >> 8, WDTVALMSB);
 183 }
 184
 185 static int wdt_update_timeout(unsigned int t)
 186 {
 187         int ret;
 188
 189         ret = superio_enter();
 190         if (ret)
 191                 return ret;
 192
 193         superio_select(GPIO);
 194         _wdt_update_timeout(t);
 195         superio_exit();
 196
 197         return 0;
 198 }
 199
 200 static int wdt_round_time(int t)
 201 {
 202         t += 59;
 203         t -= t % 60;
 204         return t;
 205 }
 206
 207 /* watchdog timer handling */
 208
 209 static int wdt_start(struct watchdog_device *wdd)
 210 {
 211         return wdt_update_timeout(wdd->timeout);
 212 }
 213
 214 static int wdt_stop(struct watchdog_device *wdd)
 215 {
 216         return wdt_update_timeout(0);
 217 }
 218
 219 /**
 220  *      wdt_set_timeout - set a new timeout value with watchdog ioctl
 221  *      @t: timeout value in seconds
 222  *
 223  *      The hardware device has a 8 or 16 bit watchdog timer (depends on
 224  *      chip version) that can be configured to count seconds or minutes.
 225  *
 226  *      Used within WDIOC_SETTIMEOUT watchdog device ioctl.
 227  */
 228
 229 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
 230 {
 231         int ret = 0;
 232
 233         if (t > max_units)
 234                 t = wdt_round_time(t);
 235
 236         wdd->timeout = t;
 237
 238         if (watchdog_hw_running(wdd))
 239                 ret = wdt_update_timeout(t);
 240
 241         return ret;
 242 }
 243
 244 static const struct watchdog_info ident = {
 245         .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 246         .firmware_version = 1,
 247         .identity = WATCHDOG_NAME,
 248 };
 249
 250 static const struct watchdog_ops wdt_ops = {
 251         .owner = THIS_MODULE,
 252         .start = wdt_start,
 253         .stop = wdt_stop,
 254         .set_timeout = wdt_set_timeout,
 255 };
 256
 257 static struct watchdog_device wdt_dev = {
 258         .info = &ident,
 259         .ops = &wdt_ops,
 260         .min_timeout = 1,
 261 };
 262
 263 static int __init it87_wdt_init(void)
 264 {
 265         u8  chip_rev;
 266         int rc;
 267
 268         rc = superio_enter();
 269         if (rc)
 270                 return rc;
 271
 272         chip_type = superio_inw(CHIPID);
 273         chip_rev  = superio_inb(CHIPREV) & 0x0f;
 274         superio_exit();
 275
 276         switch (chip_type) {
 277         case IT8702_ID:
 278                 max_units = 255;
 279                 break;
 280         case IT8712_ID:
 281                 max_units = (chip_rev < 8) ? 255 : 65535;
 282                 break;
 283         case IT8716_ID:
 284         case IT8726_ID:
 285                 max_units = 65535;
 286                 break;
 287         case IT8607_ID:
 288         case IT8620_ID:
 289         case IT8622_ID:
 290         case IT8625_ID:
 291         case IT8628_ID:
 292         case IT8655_ID:
 293         case IT8665_ID:
 294         case IT8686_ID:
 295         case IT8718_ID:
 296         case IT8720_ID:
 297         case IT8721_ID:
 298         case IT8728_ID:
 299         case IT8772_ID:
 300         case IT8783_ID:
 301         case IT8784_ID:
 302         case IT8786_ID:
 303                 max_units = 65535;
 304                 break;
 305         case IT8705_ID:
 306                 pr_err("Unsupported Chip found, Chip %04x Revision %02x\n",
 307                        chip_type, chip_rev);
 308                 return -ENODEV;
 309         case NO_DEV_ID:
 310                 pr_err("no device\n");
 311                 return -ENODEV;
 312         default:
 313                 pr_err("Unknown Chip found, Chip %04x Revision %04x\n",
 314                        chip_type, chip_rev);
 315                 return -ENODEV;
 316         }
 317
 318         rc = superio_enter();
 319         if (rc)
 320                 return rc;
 321
 322         superio_select(GPIO);
 323         superio_outb(WDT_TOV1, WDTCFG);
 324         superio_outb(0x00, WDTCTRL);
 325         superio_exit();
 326
 327         if (timeout < 1 || timeout > max_units * 60) {
 328                 timeout = DEFAULT_TIMEOUT;
 329                 pr_warn("Timeout value out of range, use default %d sec\n",
 330                         DEFAULT_TIMEOUT);
 331         }
 332
 333         if (timeout > max_units)
 334                 timeout = wdt_round_time(timeout);
 335
 336         wdt_dev.timeout = timeout;
 337         wdt_dev.max_timeout = max_units * 60;
 338
 339         watchdog_stop_on_reboot(&wdt_dev);
 340         rc = watchdog_register_device(&wdt_dev);
 341         if (rc) {
 342                 pr_err("Cannot register watchdog device (err=%d)\n", rc);
 343                 return rc;
 344         }
 345
 346         pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
 347                 chip_type, chip_rev, timeout, nowayout, testmode);
 348
 349         return 0;
 350 }
 351
 352 static void __exit it87_wdt_exit(void)
 353 {
 354         watchdog_unregister_device(&wdt_dev);
 355 }
 356
 357 module_init(it87_wdt_init);
 358 module_exit(it87_wdt_exit);
 359
 360 MODULE_AUTHOR("Oliver Schuster");
 361 MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
 362 MODULE_LICENSE("GPL");