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 *      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
  87static unsigned int max_units, chip_type;
  88
  89static unsigned int timeout = DEFAULT_TIMEOUT;
  90static int testmode = DEFAULT_TESTMODE;
  91static bool nowayout = DEFAULT_NOWAYOUT;
  92
  93module_param(timeout, int, 0);
  94MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default="
  95                __MODULE_STRING(DEFAULT_TIMEOUT));
  96module_param(testmode, int, 0);
  97MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default="
  98                __MODULE_STRING(DEFAULT_TESTMODE));
  99module_param(nowayout, bool, 0);
 100MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
 101                __MODULE_STRING(WATCHDOG_NOWAYOUT));
 102
 103/* Superio Chip */
 104
 105static 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
 120static inline void superio_exit(void)
 121{
 122        outb(0x02, REG);
 123        outb(0x02, VAL);
 124        release_region(REG, 2);
 125}
 126
 127static inline void superio_select(int ldn)
 128{
 129        outb(LDNREG, REG);
 130        outb(ldn, VAL);
 131}
 132
 133static inline int superio_inb(int reg)
 134{
 135        outb(reg, REG);
 136        return inb(VAL);
 137}
 138
 139static inline void superio_outb(int val, int reg)
 140{
 141        outb(reg, REG);
 142        outb(val, VAL);
 143}
 144
 145static 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/* Internal function, should be called after superio_select(GPIO) */
 156static void _wdt_update_timeout(unsigned int t)
 157{
 158        unsigned char cfg = WDT_KRST;
 159
 160        if (testmode)
 161                cfg = 0;
 162
 163        if (t <= max_units)
 164                cfg |= WDT_TOV1;
 165        else
 166                t /= 60;
 167
 168        if (chip_type != IT8721_ID)
 169                cfg |= WDT_PWROK;
 170
 171        superio_outb(cfg, WDTCFG);
 172        superio_outb(t, WDTVALLSB);
 173        if (max_units > 255)
 174                superio_outb(t >> 8, WDTVALMSB);
 175}
 176
 177static int wdt_update_timeout(unsigned int t)
 178{
 179        int ret;
 180
 181        ret = superio_enter();
 182        if (ret)
 183                return ret;
 184
 185        superio_select(GPIO);
 186        _wdt_update_timeout(t);
 187        superio_exit();
 188
 189        return 0;
 190}
 191
 192static int wdt_round_time(int t)
 193{
 194        t += 59;
 195        t -= t % 60;
 196        return t;
 197}
 198
 199/* watchdog timer handling */
 200
 201static int wdt_start(struct watchdog_device *wdd)
 202{
 203        return wdt_update_timeout(wdd->timeout);
 204}
 205
 206static int wdt_stop(struct watchdog_device *wdd)
 207{
 208        return wdt_update_timeout(0);
 209}
 210
 211/**
 212 *      wdt_set_timeout - set a new timeout value with watchdog ioctl
 213 *      @t: timeout value in seconds
 214 *
 215 *      The hardware device has a 8 or 16 bit watchdog timer (depends on
 216 *      chip version) that can be configured to count seconds or minutes.
 217 *
 218 *      Used within WDIOC_SETTIMEOUT watchdog device ioctl.
 219 */
 220
 221static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
 222{
 223        int ret = 0;
 224
 225        if (t > max_units)
 226                t = wdt_round_time(t);
 227
 228        wdd->timeout = t;
 229
 230        if (watchdog_hw_running(wdd))
 231                ret = wdt_update_timeout(t);
 232
 233        return ret;
 234}
 235
 236static const struct watchdog_info ident = {
 237        .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 238        .firmware_version = 1,
 239        .identity = WATCHDOG_NAME,
 240};
 241
 242static const struct watchdog_ops wdt_ops = {
 243        .owner = THIS_MODULE,
 244        .start = wdt_start,
 245        .stop = wdt_stop,
 246        .set_timeout = wdt_set_timeout,
 247};
 248
 249static struct watchdog_device wdt_dev = {
 250        .info = &ident,
 251        .ops = &wdt_ops,
 252        .min_timeout = 1,
 253};
 254
 255static int __init it87_wdt_init(void)
 256{
 257        u8  chip_rev;
 258        int rc;
 259
 260        rc = superio_enter();
 261        if (rc)
 262                return rc;
 263
 264        chip_type = superio_inw(CHIPID);
 265        chip_rev  = superio_inb(CHIPREV) & 0x0f;
 266        superio_exit();
 267
 268        switch (chip_type) {
 269        case IT8702_ID:
 270                max_units = 255;
 271                break;
 272        case IT8712_ID:
 273                max_units = (chip_rev < 8) ? 255 : 65535;
 274                break;
 275        case IT8716_ID:
 276        case IT8726_ID:
 277                max_units = 65535;
 278                break;
 279        case IT8607_ID:
 280        case IT8620_ID:
 281        case IT8622_ID:
 282        case IT8625_ID:
 283        case IT8628_ID:
 284        case IT8655_ID:
 285        case IT8665_ID:
 286        case IT8686_ID:
 287        case IT8718_ID:
 288        case IT8720_ID:
 289        case IT8721_ID:
 290        case IT8728_ID:
 291        case IT8772_ID:
 292        case IT8783_ID:
 293        case IT8784_ID:
 294        case IT8786_ID:
 295                max_units = 65535;
 296                break;
 297        case IT8705_ID:
 298                pr_err("Unsupported Chip found, Chip %04x Revision %02x\n",
 299                       chip_type, chip_rev);
 300                return -ENODEV;
 301        case NO_DEV_ID:
 302                pr_err("no device\n");
 303                return -ENODEV;
 304        default:
 305                pr_err("Unknown Chip found, Chip %04x Revision %04x\n",
 306                       chip_type, chip_rev);
 307                return -ENODEV;
 308        }
 309
 310        rc = superio_enter();
 311        if (rc)
 312                return rc;
 313
 314        superio_select(GPIO);
 315        superio_outb(WDT_TOV1, WDTCFG);
 316        superio_outb(0x00, WDTCTRL);
 317        superio_exit();
 318
 319        if (timeout < 1 || timeout > max_units * 60) {
 320                timeout = DEFAULT_TIMEOUT;
 321                pr_warn("Timeout value out of range, use default %d sec\n",
 322                        DEFAULT_TIMEOUT);
 323        }
 324
 325        if (timeout > max_units)
 326                timeout = wdt_round_time(timeout);
 327
 328        wdt_dev.timeout = timeout;
 329        wdt_dev.max_timeout = max_units * 60;
 330
 331        watchdog_stop_on_reboot(&wdt_dev);
 332        rc = watchdog_register_device(&wdt_dev);
 333        if (rc) {
 334                pr_err("Cannot register watchdog device (err=%d)\n", rc);
 335                return rc;
 336        }
 337
 338        pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
 339                chip_type, chip_rev, timeout, nowayout, testmode);
 340
 341        return 0;
 342}
 343
 344static void __exit it87_wdt_exit(void)
 345{
 346        watchdog_unregister_device(&wdt_dev);
 347}
 348
 349module_init(it87_wdt_init);
 350module_exit(it87_wdt_exit);
 351
 352MODULE_AUTHOR("Oliver Schuster");
 353MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
 354MODULE_LICENSE("GPL");
 355