drivers/watchdog/sch311x_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *      sch311x_wdt.c - Driver for the SCH311x Super-I/O chips
   4  *                      integrated watchdog.
   5  *
   6  *      (c) Copyright 2008 Wim Van Sebroeck <wim@iguana.be>.
   7  *
   8  *      Neither Wim Van Sebroeck nor Iguana vzw. admit liability nor
   9  *      provide warranty for any of this software. This material is
  10  *      provided "AS-IS" and at no charge.
  11  */
  12
  13 /*
  14  *      Includes, defines, variables, module parameters, ...
  15  */
  16
  17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  18
  19 /* Includes */
  20 #include <linux/module.h>               /* For module specific items */
  21 #include <linux/moduleparam.h>          /* For new moduleparam's */
  22 #include <linux/types.h>                /* For standard types (like size_t) */
  23 #include <linux/errno.h>                /* For the -ENODEV/... values */
  24 #include <linux/kernel.h>               /* For printk/... */
  25 #include <linux/miscdevice.h>           /* For struct miscdevice */
  26 #include <linux/watchdog.h>             /* For the watchdog specific items */
  27 #include <linux/init.h>                 /* For __init/__exit/... */
  28 #include <linux/fs.h>                   /* For file operations */
  29 #include <linux/platform_device.h>      /* For platform_driver framework */
  30 #include <linux/ioport.h>               /* For io-port access */
  31 #include <linux/spinlock.h>             /* For spin_lock/spin_unlock/... */
  32 #include <linux/uaccess.h>              /* For copy_to_user/put_user/... */
  33 #include <linux/io.h>                   /* For inb/outb/... */
  34
  35 /* Module and version information */
  36 #define DRV_NAME        "sch311x_wdt"
  37
  38 /* Runtime registers */
  39 #define GP60                    0x47
  40 #define WDT_TIME_OUT            0x65
  41 #define WDT_VAL                 0x66
  42 #define WDT_CFG                 0x67
  43 #define WDT_CTRL                0x68
  44
  45 /* internal variables */
  46 static unsigned long sch311x_wdt_is_open;
  47 static char sch311x_wdt_expect_close;
  48 static struct platform_device *sch311x_wdt_pdev;
  49
  50 static int sch311x_ioports[] = { 0x2e, 0x4e, 0x162e, 0x164e, 0x00 };
  51
  52 static struct { /* The devices private data */
  53         /* the Runtime Register base address */
  54         unsigned short runtime_reg;
  55         /* The card's boot status */
  56         int boot_status;
  57         /* the lock for io operations */
  58         spinlock_t io_lock;
  59 } sch311x_wdt_data;
  60
  61 /* Module load parameters */
  62 static unsigned short force_id;
  63 module_param(force_id, ushort, 0);
  64 MODULE_PARM_DESC(force_id, "Override the detected device ID");
  65
  66 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  67 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  68 module_param(timeout, int, 0);
  69 MODULE_PARM_DESC(timeout,
  70         "Watchdog timeout in seconds. 1<= timeout <=15300, default="
  71                 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
  72
  73 static bool nowayout = WATCHDOG_NOWAYOUT;
  74 module_param(nowayout, bool, 0);
  75 MODULE_PARM_DESC(nowayout,
  76         "Watchdog cannot be stopped once started (default="
  77                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  78
  79 /*
  80  *      Super-IO functions
  81  */
  82
  83 static inline void sch311x_sio_enter(int sio_config_port)
  84 {
  85         outb(0x55, sio_config_port);
  86 }
  87
  88 static inline void sch311x_sio_exit(int sio_config_port)
  89 {
  90         outb(0xaa, sio_config_port);
  91 }
  92
  93 static inline int sch311x_sio_inb(int sio_config_port, int reg)
  94 {
  95         outb(reg, sio_config_port);
  96         return inb(sio_config_port + 1);
  97 }
  98
  99 static inline void sch311x_sio_outb(int sio_config_port, int reg, int val)
 100 {
 101         outb(reg, sio_config_port);
 102         outb(val, sio_config_port + 1);
 103 }
 104
 105 /*
 106  *      Watchdog Operations
 107  */
 108
 109 static void sch311x_wdt_set_timeout(int t)
 110 {
 111         unsigned char timeout_unit = 0x80;
 112
 113         /* When new timeout is bigger then 255 seconds, we will use minutes */
 114         if (t > 255) {
 115                 timeout_unit = 0;
 116                 t /= 60;
 117         }
 118
 119         /* -- Watchdog Timeout --
 120          * Bit 0-6 (Reserved)
 121          * Bit 7   WDT Time-out Value Units Select
 122          *         (0 = Minutes, 1 = Seconds)
 123          */
 124         outb(timeout_unit, sch311x_wdt_data.runtime_reg + WDT_TIME_OUT);
 125
 126         /* -- Watchdog Timer Time-out Value --
 127          * Bit 0-7 Binary coded units (0=Disabled, 1..255)
 128          */
 129         outb(t, sch311x_wdt_data.runtime_reg + WDT_VAL);
 130 }
 131
 132 static void sch311x_wdt_start(void)
 133 {
 134         unsigned char t;
 135
 136         spin_lock(&sch311x_wdt_data.io_lock);
 137
 138         /* set watchdog's timeout */
 139         sch311x_wdt_set_timeout(timeout);
 140         /* enable the watchdog */
 141         /* -- General Purpose I/O Bit 6.0 --
 142          * Bit 0,   In/Out: 0 = Output, 1 = Input
 143          * Bit 1,   Polarity: 0 = No Invert, 1 = Invert
 144          * Bit 2-3, Function select: 00 = GPI/O, 01 = LED1, 11 = WDT,
 145          *                           10 = Either Edge Triggered Intr.4
 146          * Bit 4-6  (Reserved)
 147          * Bit 7,   Output Type: 0 = Push Pull Bit, 1 = Open Drain
 148          */
 149         t = inb(sch311x_wdt_data.runtime_reg + GP60);
 150         outb((t & ~0x0d) | 0x0c, sch311x_wdt_data.runtime_reg + GP60);
 151
 152         spin_unlock(&sch311x_wdt_data.io_lock);
 153
 154 }
 155
 156 static void sch311x_wdt_stop(void)
 157 {
 158         unsigned char t;
 159
 160         spin_lock(&sch311x_wdt_data.io_lock);
 161
 162         /* stop the watchdog */
 163         t = inb(sch311x_wdt_data.runtime_reg + GP60);
 164         outb((t & ~0x0d) | 0x01, sch311x_wdt_data.runtime_reg + GP60);
 165         /* disable timeout by setting it to 0 */
 166         sch311x_wdt_set_timeout(0);
 167
 168         spin_unlock(&sch311x_wdt_data.io_lock);
 169 }
 170
 171 static void sch311x_wdt_keepalive(void)
 172 {
 173         spin_lock(&sch311x_wdt_data.io_lock);
 174         sch311x_wdt_set_timeout(timeout);
 175         spin_unlock(&sch311x_wdt_data.io_lock);
 176 }
 177
 178 static int sch311x_wdt_set_heartbeat(int t)
 179 {
 180         if (t < 1 || t > (255*60))
 181                 return -EINVAL;
 182
 183         /* When new timeout is bigger then 255 seconds,
 184          * we will round up to minutes (with a max of 255) */
 185         if (t > 255)
 186                 t = (((t - 1) / 60) + 1) * 60;
 187
 188         timeout = t;
 189         return 0;
 190 }
 191
 192 static void sch311x_wdt_get_status(int *status)
 193 {
 194         unsigned char new_status;
 195
 196         *status = 0;
 197
 198         spin_lock(&sch311x_wdt_data.io_lock);
 199
 200         /* -- Watchdog timer control --
 201          * Bit 0   Status Bit: 0 = Timer counting, 1 = Timeout occurred
 202          * Bit 1   Reserved
 203          * Bit 2   Force Timeout: 1 = Forces WD timeout event (self-cleaning)
 204          * Bit 3   P20 Force Timeout enabled:
 205          *          0 = P20 activity does not generate the WD timeout event
 206          *          1 = P20 Allows rising edge of P20, from the keyboard
 207          *              controller, to force the WD timeout event.
 208          * Bit 4-7 Reserved
 209          */
 210         new_status = inb(sch311x_wdt_data.runtime_reg + WDT_CTRL);
 211         if (new_status & 0x01)
 212                 *status |= WDIOF_CARDRESET;
 213
 214         spin_unlock(&sch311x_wdt_data.io_lock);
 215 }
 216
 217 /*
 218  *      /dev/watchdog handling
 219  */
 220
 221 static ssize_t sch311x_wdt_write(struct file *file, const char __user *buf,
 222                                                 size_t count, loff_t *ppos)
 223 {
 224         if (count) {
 225                 if (!nowayout) {
 226                         size_t i;
 227
 228                         sch311x_wdt_expect_close = 0;
 229
 230                         for (i = 0; i != count; i++) {
 231                                 char c;
 232                                 if (get_user(c, buf + i))
 233                                         return -EFAULT;
 234                                 if (c == 'V')
 235                                         sch311x_wdt_expect_close = 42;
 236                         }
 237                 }
 238                 sch311x_wdt_keepalive();
 239         }
 240         return count;
 241 }
 242
 243 static long sch311x_wdt_ioctl(struct file *file, unsigned int cmd,
 244                                                         unsigned long arg)
 245 {
 246         int status;
 247         int new_timeout;
 248         void __user *argp = (void __user *)arg;
 249         int __user *p = argp;
 250         static const struct watchdog_info ident = {
 251                 .options                = WDIOF_KEEPALIVEPING |
 252                                           WDIOF_SETTIMEOUT |
 253                                           WDIOF_MAGICCLOSE,
 254                 .firmware_version       = 1,
 255                 .identity               = DRV_NAME,
 256         };
 257
 258         switch (cmd) {
 259         case WDIOC_GETSUPPORT:
 260                 if (copy_to_user(argp, &ident, sizeof(ident)))
 261                         return -EFAULT;
 262                 break;
 263
 264         case WDIOC_GETSTATUS:
 265         {
 266                 sch311x_wdt_get_status(&status);
 267                 return put_user(status, p);
 268         }
 269         case WDIOC_GETBOOTSTATUS:
 270                 return put_user(sch311x_wdt_data.boot_status, p);
 271
 272         case WDIOC_SETOPTIONS:
 273         {
 274                 int options, retval = -EINVAL;
 275
 276                 if (get_user(options, p))
 277                         return -EFAULT;
 278                 if (options & WDIOS_DISABLECARD) {
 279                         sch311x_wdt_stop();
 280                         retval = 0;
 281                 }
 282                 if (options & WDIOS_ENABLECARD) {
 283                         sch311x_wdt_start();
 284                         retval = 0;
 285                 }
 286                 return retval;
 287         }
 288         case WDIOC_KEEPALIVE:
 289                 sch311x_wdt_keepalive();
 290                 break;
 291
 292         case WDIOC_SETTIMEOUT:
 293                 if (get_user(new_timeout, p))
 294                         return -EFAULT;
 295                 if (sch311x_wdt_set_heartbeat(new_timeout))
 296                         return -EINVAL;
 297                 sch311x_wdt_keepalive();
 298                 fallthrough;
 299         case WDIOC_GETTIMEOUT:
 300                 return put_user(timeout, p);
 301         default:
 302                 return -ENOTTY;
 303         }
 304         return 0;
 305 }
 306
 307 static int sch311x_wdt_open(struct inode *inode, struct file *file)
 308 {
 309         if (test_and_set_bit(0, &sch311x_wdt_is_open))
 310                 return -EBUSY;
 311         /*
 312          *      Activate
 313          */
 314         sch311x_wdt_start();
 315         return stream_open(inode, file);
 316 }
 317
 318 static int sch311x_wdt_close(struct inode *inode, struct file *file)
 319 {
 320         if (sch311x_wdt_expect_close == 42) {
 321                 sch311x_wdt_stop();
 322         } else {
 323                 pr_crit("Unexpected close, not stopping watchdog!\n");
 324                 sch311x_wdt_keepalive();
 325         }
 326         clear_bit(0, &sch311x_wdt_is_open);
 327         sch311x_wdt_expect_close = 0;
 328         return 0;
 329 }
 330
 331 /*
 332  *      Kernel Interfaces
 333  */
 334
 335 static const struct file_operations sch311x_wdt_fops = {
 336         .owner          = THIS_MODULE,
 337         .llseek         = no_llseek,
 338         .write          = sch311x_wdt_write,
 339         .unlocked_ioctl = sch311x_wdt_ioctl,
 340         .compat_ioctl   = compat_ptr_ioctl,
 341         .open           = sch311x_wdt_open,
 342         .release        = sch311x_wdt_close,
 343 };
 344
 345 static struct miscdevice sch311x_wdt_miscdev = {
 346         .minor  = WATCHDOG_MINOR,
 347         .name   = "watchdog",
 348         .fops   = &sch311x_wdt_fops,
 349 };
 350
 351 /*
 352  *      Init & exit routines
 353  */
 354
 355 static int sch311x_wdt_probe(struct platform_device *pdev)
 356 {
 357         struct device *dev = &pdev->dev;
 358         int err;
 359
 360         spin_lock_init(&sch311x_wdt_data.io_lock);
 361
 362         if (!request_region(sch311x_wdt_data.runtime_reg + GP60, 1, DRV_NAME)) {
 363                 dev_err(dev, "Failed to request region 0x%04x-0x%04x.\n",
 364                         sch311x_wdt_data.runtime_reg + GP60,
 365                         sch311x_wdt_data.runtime_reg + GP60);
 366                 err = -EBUSY;
 367                 goto exit;
 368         }
 369
 370         if (!request_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4,
 371                                                                 DRV_NAME)) {
 372                 dev_err(dev, "Failed to request region 0x%04x-0x%04x.\n",
 373                         sch311x_wdt_data.runtime_reg + WDT_TIME_OUT,
 374                         sch311x_wdt_data.runtime_reg + WDT_CTRL);
 375                 err = -EBUSY;
 376                 goto exit_release_region;
 377         }
 378
 379         /* Make sure that the watchdog is not running */
 380         sch311x_wdt_stop();
 381
 382         /* Disable keyboard and mouse interaction and interrupt */
 383         /* -- Watchdog timer configuration --
 384          * Bit 0   Reserved
 385          * Bit 1   Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr.
 386          * Bit 2   Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr
 387          * Bit 3   Reserved
 388          * Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled,
 389          *            0001=IRQ1, 0010=(Invalid), 0011=IRQ3 to 1111=IRQ15)
 390          */
 391         outb(0, sch311x_wdt_data.runtime_reg + WDT_CFG);
 392
 393         /* Check that the heartbeat value is within it's range ;
 394          * if not reset to the default */
 395         if (sch311x_wdt_set_heartbeat(timeout)) {
 396                 sch311x_wdt_set_heartbeat(WATCHDOG_TIMEOUT);
 397                 dev_info(dev, "timeout value must be 1<=x<=15300, using %d\n",
 398                         timeout);
 399         }
 400
 401         /* Get status at boot */
 402         sch311x_wdt_get_status(&sch311x_wdt_data.boot_status);
 403
 404         sch311x_wdt_miscdev.parent = dev;
 405
 406         err = misc_register(&sch311x_wdt_miscdev);
 407         if (err != 0) {
 408                 dev_err(dev, "cannot register miscdev on minor=%d (err=%d)\n",
 409                                                         WATCHDOG_MINOR, err);
 410                 goto exit_release_region2;
 411         }
 412
 413         dev_info(dev,
 414                 "SMSC SCH311x WDT initialized. timeout=%d sec (nowayout=%d)\n",
 415                 timeout, nowayout);
 416
 417         return 0;
 418
 419 exit_release_region2:
 420         release_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4);
 421 exit_release_region:
 422         release_region(sch311x_wdt_data.runtime_reg + GP60, 1);
 423         sch311x_wdt_data.runtime_reg = 0;
 424 exit:
 425         return err;
 426 }
 427
 428 static int sch311x_wdt_remove(struct platform_device *pdev)
 429 {
 430         /* Stop the timer before we leave */
 431         if (!nowayout)
 432                 sch311x_wdt_stop();
 433
 434         /* Deregister */
 435         misc_deregister(&sch311x_wdt_miscdev);
 436         release_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4);
 437         release_region(sch311x_wdt_data.runtime_reg + GP60, 1);
 438         sch311x_wdt_data.runtime_reg = 0;
 439         return 0;
 440 }
 441
 442 static void sch311x_wdt_shutdown(struct platform_device *dev)
 443 {
 444         /* Turn the WDT off if we have a soft shutdown */
 445         sch311x_wdt_stop();
 446 }
 447
 448 static struct platform_driver sch311x_wdt_driver = {
 449         .probe          = sch311x_wdt_probe,
 450         .remove         = sch311x_wdt_remove,
 451         .shutdown       = sch311x_wdt_shutdown,
 452         .driver         = {
 453                 .name = DRV_NAME,
 454         },
 455 };
 456
 457 static int __init sch311x_detect(int sio_config_port, unsigned short *addr)
 458 {
 459         int err = 0, reg;
 460         unsigned short base_addr;
 461         unsigned char dev_id;
 462
 463         sch311x_sio_enter(sio_config_port);
 464
 465         /* Check device ID. We currently know about:
 466          * SCH3112 (0x7c), SCH3114 (0x7d), and SCH3116 (0x7f). */
 467         reg = force_id ? force_id : sch311x_sio_inb(sio_config_port, 0x20);
 468         if (!(reg == 0x7c || reg == 0x7d || reg == 0x7f)) {
 469                 err = -ENODEV;
 470                 goto exit;
 471         }
 472         dev_id = reg == 0x7c ? 2 : reg == 0x7d ? 4 : 6;
 473
 474         /* Select logical device A (runtime registers) */
 475         sch311x_sio_outb(sio_config_port, 0x07, 0x0a);
 476
 477         /* Check if Logical Device Register is currently active */
 478         if ((sch311x_sio_inb(sio_config_port, 0x30) & 0x01) == 0)
 479                 pr_info("Seems that LDN 0x0a is not active...\n");
 480
 481         /* Get the base address of the runtime registers */
 482         base_addr = (sch311x_sio_inb(sio_config_port, 0x60) << 8) |
 483                            sch311x_sio_inb(sio_config_port, 0x61);
 484         if (!base_addr) {
 485                 pr_err("Base address not set\n");
 486                 err = -ENODEV;
 487                 goto exit;
 488         }
 489         *addr = base_addr;
 490
 491         pr_info("Found an SMSC SCH311%d chip at 0x%04x\n", dev_id, base_addr);
 492
 493 exit:
 494         sch311x_sio_exit(sio_config_port);
 495         return err;
 496 }
 497
 498 static int __init sch311x_wdt_init(void)
 499 {
 500         int err, i, found = 0;
 501         unsigned short addr = 0;
 502
 503         for (i = 0; !found && sch311x_ioports[i]; i++)
 504                 if (sch311x_detect(sch311x_ioports[i], &addr) == 0)
 505                         found++;
 506
 507         if (!found)
 508                 return -ENODEV;
 509
 510         sch311x_wdt_data.runtime_reg = addr;
 511
 512         err = platform_driver_register(&sch311x_wdt_driver);
 513         if (err)
 514                 return err;
 515
 516         sch311x_wdt_pdev = platform_device_register_simple(DRV_NAME, addr,
 517                                                                 NULL, 0);
 518
 519         if (IS_ERR(sch311x_wdt_pdev)) {
 520                 err = PTR_ERR(sch311x_wdt_pdev);
 521                 goto unreg_platform_driver;
 522         }
 523
 524         return 0;
 525
 526 unreg_platform_driver:
 527         platform_driver_unregister(&sch311x_wdt_driver);
 528         return err;
 529 }
 530
 531 static void __exit sch311x_wdt_exit(void)
 532 {
 533         platform_device_unregister(sch311x_wdt_pdev);
 534         platform_driver_unregister(&sch311x_wdt_driver);
 535 }
 536
 537 module_init(sch311x_wdt_init);
 538 module_exit(sch311x_wdt_exit);
 539
 540 MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>");
 541 MODULE_DESCRIPTION("SMSC SCH311x WatchDog Timer Driver");
 542 MODULE_LICENSE("GPL");