LXR linux/drivers/watchdog/it87

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