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  *      and IT8783.
  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 IT8783_ID       0x8783
  70 #define IT8786_ID       0x8786
  71
  72 /* GPIO Configuration Registers LDN=0x07 */
  73 #define WDTCTRL         0x71
  74 #define WDTCFG          0x72
  75 #define WDTVALLSB       0x73
  76 #define WDTVALMSB       0x74
  77
  78 /* GPIO Bits WDTCFG */
  79 #define WDT_TOV1        0x80
  80 #define WDT_KRST        0x40
  81 #define WDT_TOVE        0x20
  82 #define WDT_PWROK       0x10 /* not in it8721 */
  83 #define WDT_INT_MASK    0x0f
  84
  85 static unsigned int max_units, chip_type;
  86
  87 static unsigned int timeout = DEFAULT_TIMEOUT;
  88 static int testmode = DEFAULT_TESTMODE;
  89 static bool nowayout = DEFAULT_NOWAYOUT;
  90
  91 module_param(timeout, int, 0);
  92 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default="
  93                 __MODULE_STRING(DEFAULT_TIMEOUT));
  94 module_param(testmode, int, 0);
  95 MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default="
  96                 __MODULE_STRING(DEFAULT_TESTMODE));
  97 module_param(nowayout, bool, 0);
  98 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
  99                 __MODULE_STRING(WATCHDOG_NOWAYOUT));
 100
 101 /* Superio Chip */
 102
 103 static inline int superio_enter(void)
 104 {
 105         /*
 106          * Try to reserve REG and REG + 1 for exclusive access.
 107          */
 108         if (!request_muxed_region(REG, 2, WATCHDOG_NAME))
 109                 return -EBUSY;
 110
 111         outb(0x87, REG);
 112         outb(0x01, REG);
 113         outb(0x55, REG);
 114         outb(0x55, REG);
 115         return 0;
 116 }
 117
 118 static inline void superio_exit(void)
 119 {
 120         outb(0x02, REG);
 121         outb(0x02, VAL);
 122         release_region(REG, 2);
 123 }
 124
 125 static inline void superio_select(int ldn)
 126 {
 127         outb(LDNREG, REG);
 128         outb(ldn, VAL);
 129 }
 130
 131 static inline int superio_inb(int reg)
 132 {
 133         outb(reg, REG);
 134         return inb(VAL);
 135 }
 136
 137 static inline void superio_outb(int val, int reg)
 138 {
 139         outb(reg, REG);
 140         outb(val, VAL);
 141 }
 142
 143 static inline int superio_inw(int reg)
 144 {
 145         int val;
 146         outb(reg++, REG);
 147         val = inb(VAL) << 8;
 148         outb(reg, REG);
 149         val |= inb(VAL);
 150         return val;
 151 }
 152
 153 static inline void superio_outw(int val, int reg)
 154 {
 155         outb(reg++, REG);
 156         outb(val >> 8, VAL);
 157         outb(reg, REG);
 158         outb(val, VAL);
 159 }
 160
 161 /* Internal function, should be called after superio_select(GPIO) */
 162 static void _wdt_update_timeout(unsigned int t)
 163 {
 164         unsigned char cfg = WDT_KRST;
 165
 166         if (testmode)
 167                 cfg = 0;
 168
 169         if (t <= max_units)
 170                 cfg |= WDT_TOV1;
 171         else
 172                 t /= 60;
 173
 174         if (chip_type != IT8721_ID)
 175                 cfg |= WDT_PWROK;
 176
 177         superio_outb(cfg, WDTCFG);
 178         superio_outb(t, WDTVALLSB);
 179         if (max_units > 255)
 180                 superio_outb(t >> 8, WDTVALMSB);
 181 }
 182
 183 static int wdt_update_timeout(unsigned int t)
 184 {
 185         int ret;
 186
 187         ret = superio_enter();
 188         if (ret)
 189                 return ret;
 190
 191         superio_select(GPIO);
 192         _wdt_update_timeout(t);
 193         superio_exit();
 194
 195         return 0;
 196 }
 197
 198 static int wdt_round_time(int t)
 199 {
 200         t += 59;
 201         t -= t % 60;
 202         return t;
 203 }
 204
 205 /* watchdog timer handling */
 206
 207 static int wdt_start(struct watchdog_device *wdd)
 208 {
 209         return wdt_update_timeout(wdd->timeout);
 210 }
 211
 212 static int wdt_stop(struct watchdog_device *wdd)
 213 {
 214         return wdt_update_timeout(0);
 215 }
 216
 217 /**
 218  *      wdt_set_timeout - set a new timeout value with watchdog ioctl
 219  *      @t: timeout value in seconds
 220  *
 221  *      The hardware device has a 8 or 16 bit watchdog timer (depends on
 222  *      chip version) that can be configured to count seconds or minutes.
 223  *
 224  *      Used within WDIOC_SETTIMEOUT watchdog device ioctl.
 225  */
 226
 227 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
 228 {
 229         int ret = 0;
 230
 231         if (t > max_units)
 232                 t = wdt_round_time(t);
 233
 234         wdd->timeout = t;
 235
 236         if (watchdog_hw_running(wdd))
 237                 ret = wdt_update_timeout(t);
 238
 239         return ret;
 240 }
 241
 242 static const struct watchdog_info ident = {
 243         .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 244         .firmware_version = 1,
 245         .identity = WATCHDOG_NAME,
 246 };
 247
 248 static const struct watchdog_ops wdt_ops = {
 249         .owner = THIS_MODULE,
 250         .start = wdt_start,
 251         .stop = wdt_stop,
 252         .set_timeout = wdt_set_timeout,
 253 };
 254
 255 static struct watchdog_device wdt_dev = {
 256         .info = &ident,
 257         .ops = &wdt_ops,
 258         .min_timeout = 1,
 259 };
 260
 261 static int __init it87_wdt_init(void)
 262 {
 263         u8  chip_rev;
 264         int rc;
 265
 266         rc = superio_enter();
 267         if (rc)
 268                 return rc;
 269
 270         chip_type = superio_inw(CHIPID);
 271         chip_rev  = superio_inb(CHIPREV) & 0x0f;
 272         superio_exit();
 273
 274         switch (chip_type) {
 275         case IT8702_ID:
 276                 max_units = 255;
 277                 break;
 278         case IT8712_ID:
 279                 max_units = (chip_rev < 8) ? 255 : 65535;
 280                 break;
 281         case IT8716_ID:
 282         case IT8726_ID:
 283                 max_units = 65535;
 284                 break;
 285         case IT8607_ID:
 286         case IT8620_ID:
 287         case IT8622_ID:
 288         case IT8625_ID:
 289         case IT8628_ID:
 290         case IT8655_ID:
 291         case IT8665_ID:
 292         case IT8686_ID:
 293         case IT8718_ID:
 294         case IT8720_ID:
 295         case IT8721_ID:
 296         case IT8728_ID:
 297         case IT8783_ID:
 298         case IT8786_ID:
 299                 max_units = 65535;
 300                 break;
 301         case IT8705_ID:
 302                 pr_err("Unsupported Chip found, Chip %04x Revision %02x\n",
 303                        chip_type, chip_rev);
 304                 return -ENODEV;
 305         case NO_DEV_ID:
 306                 pr_err("no device\n");
 307                 return -ENODEV;
 308         default:
 309                 pr_err("Unknown Chip found, Chip %04x Revision %04x\n",
 310                        chip_type, chip_rev);
 311                 return -ENODEV;
 312         }
 313
 314         rc = superio_enter();
 315         if (rc)
 316                 return rc;
 317
 318         superio_select(GPIO);
 319         superio_outb(WDT_TOV1, WDTCFG);
 320         superio_outb(0x00, WDTCTRL);
 321         superio_exit();
 322
 323         if (timeout < 1 || timeout > max_units * 60) {
 324                 timeout = DEFAULT_TIMEOUT;
 325                 pr_warn("Timeout value out of range, use default %d sec\n",
 326                         DEFAULT_TIMEOUT);
 327         }
 328
 329         if (timeout > max_units)
 330                 timeout = wdt_round_time(timeout);
 331
 332         wdt_dev.timeout = timeout;
 333         wdt_dev.max_timeout = max_units * 60;
 334
 335         watchdog_stop_on_reboot(&wdt_dev);
 336         rc = watchdog_register_device(&wdt_dev);
 337         if (rc) {
 338                 pr_err("Cannot register watchdog device (err=%d)\n", rc);
 339                 return rc;
 340         }
 341
 342         pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
 343                 chip_type, chip_rev, timeout, nowayout, testmode);
 344
 345         return 0;
 346 }
 347
 348 static void __exit it87_wdt_exit(void)
 349 {
 350         watchdog_unregister_device(&wdt_dev);
 351 }
 352
 353 module_init(it87_wdt_init);
 354 module_exit(it87_wdt_exit);
 355
 356 MODULE_AUTHOR("Oliver Schuster");
 357 MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
 358 MODULE_LICENSE("GPL");