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, IT8613, IT8620, IT8622, IT8625, IT8628, IT8655, IT8659,
  17  *      IT8665, IT8686, IT8702, IT8712, IT8716, IT8718, IT8720, IT8721,
  18  *      IT8726, IT8728, IT8772, IT8783, IT8784 and IT8786.
  19  */
  20
  21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  22
  23 #include <linux/bits.h>
  24 #include <linux/dmi.h>
  25 #include <linux/init.h>
  26 #include <linux/io.h>
  27 #include <linux/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/moduleparam.h>
  30 #include <linux/types.h>
  31 #include <linux/watchdog.h>
  32
  33 #define WATCHDOG_NAME           "IT87 WDT"
  34
  35 /* Defaults for Module Parameter */
  36 #define DEFAULT_TIMEOUT         60
  37 #define DEFAULT_TESTMODE        0
  38 #define DEFAULT_NOWAYOUT        WATCHDOG_NOWAYOUT
  39
  40 /* IO Ports */
  41 #define REG             0x2e
  42 #define VAL             0x2f
  43
  44 /* Logical device Numbers LDN */
  45 #define EC              0x04
  46 #define GPIO            0x07
  47
  48 /* Configuration Registers and Functions */
  49 #define LDNREG          0x07
  50 #define CHIPID          0x20
  51 #define CHIPREV         0x22
  52
  53 /* Chip Id numbers */
  54 #define NO_DEV_ID       0xffff
  55 #define IT8607_ID       0x8607
  56 #define IT8613_ID       0x8613
  57 #define IT8620_ID       0x8620
  58 #define IT8622_ID       0x8622
  59 #define IT8625_ID       0x8625
  60 #define IT8628_ID       0x8628
  61 #define IT8655_ID       0x8655
  62 #define IT8659_ID       0x8659
  63 #define IT8665_ID       0x8665
  64 #define IT8686_ID       0x8686
  65 #define IT8702_ID       0x8702
  66 #define IT8705_ID       0x8705
  67 #define IT8712_ID       0x8712
  68 #define IT8716_ID       0x8716
  69 #define IT8718_ID       0x8718
  70 #define IT8720_ID       0x8720
  71 #define IT8721_ID       0x8721
  72 #define IT8726_ID       0x8726  /* the data sheet suggest wrongly 0x8716 */
  73 #define IT8728_ID       0x8728
  74 #define IT8772_ID       0x8772
  75 #define IT8783_ID       0x8783
  76 #define IT8784_ID       0x8784
  77 #define IT8786_ID       0x8786
  78
  79 /* Environment Controller Configuration Registers LDN=0x04 */
  80 #define SCR1            0xfa
  81
  82 /* Environment Controller Bits SCR1 */
  83 #define WDT_PWRGD       0x20
  84
  85 /* GPIO Configuration Registers LDN=0x07 */
  86 #define WDTCTRL         0x71
  87 #define WDTCFG          0x72
  88 #define WDTVALLSB       0x73
  89 #define WDTVALMSB       0x74
  90
  91 /* GPIO Bits WDTCFG */
  92 #define WDT_TOV1        0x80
  93 #define WDT_KRST        0x40
  94 #define WDT_TOVE        0x20
  95 #define WDT_PWROK       0x10 /* not in it8721 */
  96 #define WDT_INT_MASK    0x0f
  97
  98 static unsigned int max_units, chip_type;
  99
 100 static unsigned int timeout = DEFAULT_TIMEOUT;
 101 static int testmode = DEFAULT_TESTMODE;
 102 static bool nowayout = DEFAULT_NOWAYOUT;
 103
 104 module_param(timeout, int, 0);
 105 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default="
 106                 __MODULE_STRING(DEFAULT_TIMEOUT));
 107 module_param(testmode, int, 0);
 108 MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default="
 109                 __MODULE_STRING(DEFAULT_TESTMODE));
 110 module_param(nowayout, bool, 0);
 111 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
 112                 __MODULE_STRING(WATCHDOG_NOWAYOUT));
 113
 114 /* Superio Chip */
 115
 116 static inline int superio_enter(void)
 117 {
 118         /*
 119          * Try to reserve REG and REG + 1 for exclusive access.
 120          */
 121         if (!request_muxed_region(REG, 2, WATCHDOG_NAME))
 122                 return -EBUSY;
 123
 124         outb(0x87, REG);
 125         outb(0x01, REG);
 126         outb(0x55, REG);
 127         outb(0x55, REG);
 128         return 0;
 129 }
 130
 131 static inline void superio_exit(void)
 132 {
 133         outb(0x02, REG);
 134         outb(0x02, VAL);
 135         release_region(REG, 2);
 136 }
 137
 138 static inline void superio_select(int ldn)
 139 {
 140         outb(LDNREG, REG);
 141         outb(ldn, VAL);
 142 }
 143
 144 static inline int superio_inb(int reg)
 145 {
 146         outb(reg, REG);
 147         return inb(VAL);
 148 }
 149
 150 static inline void superio_outb(int val, int reg)
 151 {
 152         outb(reg, REG);
 153         outb(val, VAL);
 154 }
 155
 156 static inline int superio_inw(int reg)
 157 {
 158         int val;
 159
 160         outb(reg++, REG);
 161         val = inb(VAL) << 8;
 162         outb(reg, REG);
 163         val |= inb(VAL);
 164         return val;
 165 }
 166
 167 /* Internal function, should be called after superio_select(GPIO) */
 168 static void _wdt_update_timeout(unsigned int t)
 169 {
 170         unsigned char cfg = WDT_KRST;
 171
 172         if (testmode)
 173                 cfg = 0;
 174
 175         if (t <= max_units)
 176                 cfg |= WDT_TOV1;
 177         else
 178                 t /= 60;
 179
 180         if (chip_type != IT8721_ID)
 181                 cfg |= WDT_PWROK;
 182
 183         superio_outb(cfg, WDTCFG);
 184         superio_outb(t, WDTVALLSB);
 185         if (max_units > 255)
 186                 superio_outb(t >> 8, WDTVALMSB);
 187 }
 188
 189 static int wdt_update_timeout(unsigned int t)
 190 {
 191         int ret;
 192
 193         ret = superio_enter();
 194         if (ret)
 195                 return ret;
 196
 197         superio_select(GPIO);
 198         _wdt_update_timeout(t);
 199         superio_exit();
 200
 201         return 0;
 202 }
 203
 204 static int wdt_round_time(int t)
 205 {
 206         t += 59;
 207         t -= t % 60;
 208         return t;
 209 }
 210
 211 /* watchdog timer handling */
 212
 213 static int wdt_start(struct watchdog_device *wdd)
 214 {
 215         return wdt_update_timeout(wdd->timeout);
 216 }
 217
 218 static int wdt_stop(struct watchdog_device *wdd)
 219 {
 220         return wdt_update_timeout(0);
 221 }
 222
 223 /**
 224  *      wdt_set_timeout - set a new timeout value with watchdog ioctl
 225  *      @wdd: pointer to the watchdog_device structure
 226  *      @t: timeout value in seconds
 227  *
 228  *      The hardware device has a 8 or 16 bit watchdog timer (depends on
 229  *      chip version) that can be configured to count seconds or minutes.
 230  *
 231  *      Used within WDIOC_SETTIMEOUT watchdog device ioctl.
 232  *
 233  *      Return: 0 if the timeout was set successfully, or a negative error code on
 234  *      failure.
 235  */
 236
 237 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
 238 {
 239         int ret = 0;
 240
 241         if (t > max_units)
 242                 t = wdt_round_time(t);
 243
 244         wdd->timeout = t;
 245
 246         if (watchdog_hw_running(wdd))
 247                 ret = wdt_update_timeout(t);
 248
 249         return ret;
 250 }
 251
 252 enum {
 253         IT87_WDT_OUTPUT_THROUGH_PWRGD   = BIT(0),
 254 };
 255
 256 static const struct dmi_system_id it87_quirks[] = {
 257         {
 258                 /* Qotom Q30900P (IT8786) */
 259                 .matches = {
 260                         DMI_EXACT_MATCH(DMI_BOARD_NAME, "QCML04"),
 261                 },
 262                 .driver_data = (void *)IT87_WDT_OUTPUT_THROUGH_PWRGD,
 263         },
 264         {}
 265 };
 266
 267 static const struct watchdog_info ident = {
 268         .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 269         .firmware_version = 1,
 270         .identity = WATCHDOG_NAME,
 271 };
 272
 273 static const struct watchdog_ops wdt_ops = {
 274         .owner = THIS_MODULE,
 275         .start = wdt_start,
 276         .stop = wdt_stop,
 277         .set_timeout = wdt_set_timeout,
 278 };
 279
 280 static struct watchdog_device wdt_dev = {
 281         .info = &ident,
 282         .ops = &wdt_ops,
 283         .min_timeout = 1,
 284 };
 285
 286 static int __init it87_wdt_init(void)
 287 {
 288         const struct dmi_system_id *dmi_id;
 289         u8  chip_rev;
 290         u8 ctrl;
 291         int quirks = 0;
 292         int rc;
 293
 294         rc = superio_enter();
 295         if (rc)
 296                 return rc;
 297
 298         chip_type = superio_inw(CHIPID);
 299         chip_rev  = superio_inb(CHIPREV) & 0x0f;
 300         superio_exit();
 301
 302         dmi_id = dmi_first_match(it87_quirks);
 303         if (dmi_id)
 304                 quirks = (long)dmi_id->driver_data;
 305
 306         switch (chip_type) {
 307         case IT8702_ID:
 308                 max_units = 255;
 309                 break;
 310         case IT8712_ID:
 311                 max_units = (chip_rev < 8) ? 255 : 65535;
 312                 break;
 313         case IT8607_ID:
 314         case IT8613_ID:
 315         case IT8620_ID:
 316         case IT8622_ID:
 317         case IT8625_ID:
 318         case IT8628_ID:
 319         case IT8655_ID:
 320         case IT8659_ID:
 321         case IT8665_ID:
 322         case IT8686_ID:
 323         case IT8716_ID:
 324         case IT8718_ID:
 325         case IT8720_ID:
 326         case IT8721_ID:
 327         case IT8726_ID:
 328         case IT8728_ID:
 329         case IT8772_ID:
 330         case IT8783_ID:
 331         case IT8784_ID:
 332         case IT8786_ID:
 333                 max_units = 65535;
 334                 break;
 335         case IT8705_ID:
 336                 pr_err("Unsupported Chip found, Chip %04x Revision %02x\n",
 337                        chip_type, chip_rev);
 338                 return -ENODEV;
 339         case NO_DEV_ID:
 340                 pr_err("no device\n");
 341                 return -ENODEV;
 342         default:
 343                 pr_err("Unknown Chip found, Chip %04x Revision %04x\n",
 344                        chip_type, chip_rev);
 345                 return -ENODEV;
 346         }
 347
 348         rc = superio_enter();
 349         if (rc)
 350                 return rc;
 351
 352         superio_select(GPIO);
 353         superio_outb(WDT_TOV1, WDTCFG);
 354
 355         switch (chip_type) {
 356         case IT8784_ID:
 357         case IT8786_ID:
 358                 ctrl = superio_inb(WDTCTRL);
 359                 ctrl &= 0x08;
 360                 superio_outb(ctrl, WDTCTRL);
 361                 break;
 362         default:
 363                 superio_outb(0x00, WDTCTRL);
 364         }
 365
 366         if (quirks & IT87_WDT_OUTPUT_THROUGH_PWRGD) {
 367                 superio_select(EC);
 368                 ctrl = superio_inb(SCR1);
 369                 if (!(ctrl & WDT_PWRGD)) {
 370                         ctrl |= WDT_PWRGD;
 371                         superio_outb(ctrl, SCR1);
 372                 }
 373         }
 374
 375         superio_exit();
 376
 377         if (timeout < 1 || timeout > max_units * 60) {
 378                 timeout = DEFAULT_TIMEOUT;
 379                 pr_warn("Timeout value out of range, use default %d sec\n",
 380                         DEFAULT_TIMEOUT);
 381         }
 382
 383         if (timeout > max_units)
 384                 timeout = wdt_round_time(timeout);
 385
 386         wdt_dev.timeout = timeout;
 387         wdt_dev.max_timeout = max_units * 60;
 388
 389         watchdog_stop_on_reboot(&wdt_dev);
 390         rc = watchdog_register_device(&wdt_dev);
 391         if (rc)
 392                 return rc;
 393
 394         pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
 395                 chip_type, chip_rev, timeout, nowayout, testmode);
 396
 397         return 0;
 398 }
 399
 400 static void __exit it87_wdt_exit(void)
 401 {
 402         watchdog_unregister_device(&wdt_dev);
 403 }
 404
 405 module_init(it87_wdt_init);
 406 module_exit(it87_wdt_exit);
 407
 408 MODULE_AUTHOR("Oliver Schuster");
 409 MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
 410 MODULE_LICENSE("GPL");