drivers/watchdog/wdat_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ACPI Hardware Watchdog (WDAT) driver.
   4  *
   5  * Copyright (C) 2016, Intel Corporation
   6  * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
   7  */
   8
   9 #include <linux/acpi.h>
  10 #include <linux/ioport.h>
  11 #include <linux/module.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/pm.h>
  14 #include <linux/watchdog.h>
  15
  16 #define MAX_WDAT_ACTIONS ACPI_WDAT_ACTION_RESERVED
  17
  18 /**
  19  * struct wdat_instruction - Single ACPI WDAT instruction
  20  * @entry: Copy of the ACPI table instruction
  21  * @reg: Register the instruction is accessing
  22  * @node: Next instruction in action sequence
  23  */
  24 struct wdat_instruction {
  25         struct acpi_wdat_entry entry;
  26         void __iomem *reg;
  27         struct list_head node;
  28 };
  29
  30 /**
  31  * struct wdat_wdt - ACPI WDAT watchdog device
  32  * @pdev: Parent platform device
  33  * @wdd: Watchdog core device
  34  * @period: How long is one watchdog period in ms
  35  * @stopped_in_sleep: Is this watchdog stopped by the firmware in S1-S5
  36  * @stopped: Was the watchdog stopped by the driver in suspend
  37  * @actions: An array of instruction lists indexed by an action number from
  38  *           the WDAT table. There can be %NULL entries for not implemented
  39  *           actions.
  40  */
  41 struct wdat_wdt {
  42         struct platform_device *pdev;
  43         struct watchdog_device wdd;
  44         unsigned int period;
  45         bool stopped_in_sleep;
  46         bool stopped;
  47         struct list_head *instructions[MAX_WDAT_ACTIONS];
  48 };
  49
  50 #define to_wdat_wdt(wdd) container_of(wdd, struct wdat_wdt, wdd)
  51
  52 static bool nowayout = WATCHDOG_NOWAYOUT;
  53 module_param(nowayout, bool, 0);
  54 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  55                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  56
  57 static int wdat_wdt_read(struct wdat_wdt *wdat,
  58          const struct wdat_instruction *instr, u32 *value)
  59 {
  60         const struct acpi_generic_address *gas = &instr->entry.register_region;
  61
  62         switch (gas->access_width) {
  63         case 1:
  64                 *value = ioread8(instr->reg);
  65                 break;
  66         case 2:
  67                 *value = ioread16(instr->reg);
  68                 break;
  69         case 3:
  70                 *value = ioread32(instr->reg);
  71                 break;
  72         default:
  73                 return -EINVAL;
  74         }
  75
  76         dev_dbg(&wdat->pdev->dev, "Read %#x from 0x%08llx\n", *value,
  77                 gas->address);
  78
  79         return 0;
  80 }
  81
  82 static int wdat_wdt_write(struct wdat_wdt *wdat,
  83         const struct wdat_instruction *instr, u32 value)
  84 {
  85         const struct acpi_generic_address *gas = &instr->entry.register_region;
  86
  87         switch (gas->access_width) {
  88         case 1:
  89                 iowrite8((u8)value, instr->reg);
  90                 break;
  91         case 2:
  92                 iowrite16((u16)value, instr->reg);
  93                 break;
  94         case 3:
  95                 iowrite32(value, instr->reg);
  96                 break;
  97         default:
  98                 return -EINVAL;
  99         }
 100
 101         dev_dbg(&wdat->pdev->dev, "Wrote %#x to 0x%08llx\n", value,
 102                 gas->address);
 103
 104         return 0;
 105 }
 106
 107 static int wdat_wdt_run_action(struct wdat_wdt *wdat, unsigned int action,
 108                                u32 param, u32 *retval)
 109 {
 110         struct wdat_instruction *instr;
 111
 112         if (action >= ARRAY_SIZE(wdat->instructions))
 113                 return -EINVAL;
 114
 115         if (!wdat->instructions[action])
 116                 return -EOPNOTSUPP;
 117
 118         dev_dbg(&wdat->pdev->dev, "Running action %#x\n", action);
 119
 120         /* Run each instruction sequentially */
 121         list_for_each_entry(instr, wdat->instructions[action], node) {
 122                 const struct acpi_wdat_entry *entry = &instr->entry;
 123                 const struct acpi_generic_address *gas;
 124                 u32 flags, value, mask, x, y;
 125                 bool preserve;
 126                 int ret;
 127
 128                 gas = &entry->register_region;
 129
 130                 preserve = entry->instruction & ACPI_WDAT_PRESERVE_REGISTER;
 131                 flags = entry->instruction & ~ACPI_WDAT_PRESERVE_REGISTER;
 132                 value = entry->value;
 133                 mask = entry->mask;
 134
 135                 switch (flags) {
 136                 case ACPI_WDAT_READ_VALUE:
 137                         ret = wdat_wdt_read(wdat, instr, &x);
 138                         if (ret)
 139                                 return ret;
 140                         x >>= gas->bit_offset;
 141                         x &= mask;
 142                         if (retval)
 143                                 *retval = x == value;
 144                         break;
 145
 146                 case ACPI_WDAT_READ_COUNTDOWN:
 147                         ret = wdat_wdt_read(wdat, instr, &x);
 148                         if (ret)
 149                                 return ret;
 150                         x >>= gas->bit_offset;
 151                         x &= mask;
 152                         if (retval)
 153                                 *retval = x;
 154                         break;
 155
 156                 case ACPI_WDAT_WRITE_VALUE:
 157                         x = value & mask;
 158                         x <<= gas->bit_offset;
 159                         if (preserve) {
 160                                 ret = wdat_wdt_read(wdat, instr, &y);
 161                                 if (ret)
 162                                         return ret;
 163                                 y = y & ~(mask << gas->bit_offset);
 164                                 x |= y;
 165                         }
 166                         ret = wdat_wdt_write(wdat, instr, x);
 167                         if (ret)
 168                                 return ret;
 169                         break;
 170
 171                 case ACPI_WDAT_WRITE_COUNTDOWN:
 172                         x = param;
 173                         x &= mask;
 174                         x <<= gas->bit_offset;
 175                         if (preserve) {
 176                                 ret = wdat_wdt_read(wdat, instr, &y);
 177                                 if (ret)
 178                                         return ret;
 179                                 y = y & ~(mask << gas->bit_offset);
 180                                 x |= y;
 181                         }
 182                         ret = wdat_wdt_write(wdat, instr, x);
 183                         if (ret)
 184                                 return ret;
 185                         break;
 186
 187                 default:
 188                         dev_err(&wdat->pdev->dev, "Unknown instruction: %u\n",
 189                                 flags);
 190                         return -EINVAL;
 191                 }
 192         }
 193
 194         return 0;
 195 }
 196
 197 static int wdat_wdt_enable_reboot(struct wdat_wdt *wdat)
 198 {
 199         int ret;
 200
 201         /*
 202          * WDAT specification says that the watchdog is required to reboot
 203          * the system when it fires. However, it also states that it is
 204          * recommeded to make it configurable through hardware register. We
 205          * enable reboot now if it is configrable, just in case.
 206          */
 207         ret = wdat_wdt_run_action(wdat, ACPI_WDAT_SET_REBOOT, 0, NULL);
 208         if (ret && ret != -EOPNOTSUPP) {
 209                 dev_err(&wdat->pdev->dev,
 210                         "Failed to enable reboot when watchdog triggers\n");
 211                 return ret;
 212         }
 213
 214         return 0;
 215 }
 216
 217 static void wdat_wdt_boot_status(struct wdat_wdt *wdat)
 218 {
 219         u32 boot_status = 0;
 220         int ret;
 221
 222         ret = wdat_wdt_run_action(wdat, ACPI_WDAT_GET_STATUS, 0, &boot_status);
 223         if (ret && ret != -EOPNOTSUPP) {
 224                 dev_err(&wdat->pdev->dev, "Failed to read boot status\n");
 225                 return;
 226         }
 227
 228         if (boot_status)
 229                 wdat->wdd.bootstatus = WDIOF_CARDRESET;
 230
 231         /* Clear the boot status in case BIOS did not do it */
 232         ret = wdat_wdt_run_action(wdat, ACPI_WDAT_SET_STATUS, 0, NULL);
 233         if (ret && ret != -EOPNOTSUPP)
 234                 dev_err(&wdat->pdev->dev, "Failed to clear boot status\n");
 235 }
 236
 237 static void wdat_wdt_set_running(struct wdat_wdt *wdat)
 238 {
 239         u32 running = 0;
 240         int ret;
 241
 242         ret = wdat_wdt_run_action(wdat, ACPI_WDAT_GET_RUNNING_STATE, 0,
 243                                   &running);
 244         if (ret && ret != -EOPNOTSUPP)
 245                 dev_err(&wdat->pdev->dev, "Failed to read running state\n");
 246
 247         if (running)
 248                 set_bit(WDOG_HW_RUNNING, &wdat->wdd.status);
 249 }
 250
 251 static int wdat_wdt_start(struct watchdog_device *wdd)
 252 {
 253         return wdat_wdt_run_action(to_wdat_wdt(wdd),
 254                                    ACPI_WDAT_SET_RUNNING_STATE, 0, NULL);
 255 }
 256
 257 static int wdat_wdt_stop(struct watchdog_device *wdd)
 258 {
 259         return wdat_wdt_run_action(to_wdat_wdt(wdd),
 260                                    ACPI_WDAT_SET_STOPPED_STATE, 0, NULL);
 261 }
 262
 263 static int wdat_wdt_ping(struct watchdog_device *wdd)
 264 {
 265         return wdat_wdt_run_action(to_wdat_wdt(wdd), ACPI_WDAT_RESET, 0, NULL);
 266 }
 267
 268 static int wdat_wdt_set_timeout(struct watchdog_device *wdd,
 269                                 unsigned int timeout)
 270 {
 271         struct wdat_wdt *wdat = to_wdat_wdt(wdd);
 272         unsigned int periods;
 273         int ret;
 274
 275         periods = timeout * 1000 / wdat->period;
 276         ret = wdat_wdt_run_action(wdat, ACPI_WDAT_SET_COUNTDOWN, periods, NULL);
 277         if (!ret)
 278                 wdd->timeout = timeout;
 279         return ret;
 280 }
 281
 282 static unsigned int wdat_wdt_get_timeleft(struct watchdog_device *wdd)
 283 {
 284         struct wdat_wdt *wdat = to_wdat_wdt(wdd);
 285         u32 periods = 0;
 286
 287         wdat_wdt_run_action(wdat, ACPI_WDAT_GET_CURRENT_COUNTDOWN, 0, &periods);
 288         return periods * wdat->period / 1000;
 289 }
 290
 291 static const struct watchdog_info wdat_wdt_info = {
 292         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 293         .firmware_version = 0,
 294         .identity = "wdat_wdt",
 295 };
 296
 297 static const struct watchdog_ops wdat_wdt_ops = {
 298         .owner = THIS_MODULE,
 299         .start = wdat_wdt_start,
 300         .stop = wdat_wdt_stop,
 301         .ping = wdat_wdt_ping,
 302         .set_timeout = wdat_wdt_set_timeout,
 303         .get_timeleft = wdat_wdt_get_timeleft,
 304 };
 305
 306 static int wdat_wdt_probe(struct platform_device *pdev)
 307 {
 308         struct device *dev = &pdev->dev;
 309         const struct acpi_wdat_entry *entries;
 310         const struct acpi_table_wdat *tbl;
 311         struct wdat_wdt *wdat;
 312         struct resource *res;
 313         void __iomem **regs;
 314         acpi_status status;
 315         int i, ret;
 316
 317         status = acpi_get_table(ACPI_SIG_WDAT, 0,
 318                                 (struct acpi_table_header **)&tbl);
 319         if (ACPI_FAILURE(status))
 320                 return -ENODEV;
 321
 322         wdat = devm_kzalloc(dev, sizeof(*wdat), GFP_KERNEL);
 323         if (!wdat)
 324                 return -ENOMEM;
 325
 326         regs = devm_kcalloc(dev, pdev->num_resources, sizeof(*regs),
 327                             GFP_KERNEL);
 328         if (!regs)
 329                 return -ENOMEM;
 330
 331         /* WDAT specification wants to have >= 1ms period */
 332         if (tbl->timer_period < 1)
 333                 return -EINVAL;
 334         if (tbl->min_count > tbl->max_count)
 335                 return -EINVAL;
 336
 337         wdat->period = tbl->timer_period;
 338         wdat->wdd.min_hw_heartbeat_ms = wdat->period * tbl->min_count;
 339         wdat->wdd.max_hw_heartbeat_ms = wdat->period * tbl->max_count;
 340         wdat->stopped_in_sleep = tbl->flags & ACPI_WDAT_STOPPED;
 341         wdat->wdd.info = &wdat_wdt_info;
 342         wdat->wdd.ops = &wdat_wdt_ops;
 343         wdat->pdev = pdev;
 344
 345         /* Request and map all resources */
 346         for (i = 0; i < pdev->num_resources; i++) {
 347                 void __iomem *reg;
 348
 349                 res = &pdev->resource[i];
 350                 if (resource_type(res) == IORESOURCE_MEM) {
 351                         reg = devm_ioremap_resource(dev, res);
 352                         if (IS_ERR(reg))
 353                                 return PTR_ERR(reg);
 354                 } else if (resource_type(res) == IORESOURCE_IO) {
 355                         reg = devm_ioport_map(dev, res->start, 1);
 356                         if (!reg)
 357                                 return -ENOMEM;
 358                 } else {
 359                         dev_err(dev, "Unsupported resource\n");
 360                         return -EINVAL;
 361                 }
 362
 363                 regs[i] = reg;
 364         }
 365
 366         entries = (struct acpi_wdat_entry *)(tbl + 1);
 367         for (i = 0; i < tbl->entries; i++) {
 368                 const struct acpi_generic_address *gas;
 369                 struct wdat_instruction *instr;
 370                 struct list_head *instructions;
 371                 unsigned int action;
 372                 struct resource r;
 373                 int j;
 374
 375                 action = entries[i].action;
 376                 if (action >= MAX_WDAT_ACTIONS) {
 377                         dev_dbg(dev, "Skipping unknown action: %u\n", action);
 378                         continue;
 379                 }
 380
 381                 instr = devm_kzalloc(dev, sizeof(*instr), GFP_KERNEL);
 382                 if (!instr)
 383                         return -ENOMEM;
 384
 385                 INIT_LIST_HEAD(&instr->node);
 386                 instr->entry = entries[i];
 387
 388                 gas = &entries[i].register_region;
 389
 390                 memset(&r, 0, sizeof(r));
 391                 r.start = gas->address;
 392                 r.end = r.start + gas->access_width - 1;
 393                 if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
 394                         r.flags = IORESOURCE_MEM;
 395                 } else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
 396                         r.flags = IORESOURCE_IO;
 397                 } else {
 398                         dev_dbg(dev, "Unsupported address space: %d\n",
 399                                 gas->space_id);
 400                         continue;
 401                 }
 402
 403                 /* Find the matching resource */
 404                 for (j = 0; j < pdev->num_resources; j++) {
 405                         res = &pdev->resource[j];
 406                         if (resource_contains(res, &r)) {
 407                                 instr->reg = regs[j] + r.start - res->start;
 408                                 break;
 409                         }
 410                 }
 411
 412                 if (!instr->reg) {
 413                         dev_err(dev, "I/O resource not found\n");
 414                         return -EINVAL;
 415                 }
 416
 417                 instructions = wdat->instructions[action];
 418                 if (!instructions) {
 419                         instructions = devm_kzalloc(dev,
 420                                                     sizeof(*instructions),
 421                                                     GFP_KERNEL);
 422                         if (!instructions)
 423                                 return -ENOMEM;
 424
 425                         INIT_LIST_HEAD(instructions);
 426                         wdat->instructions[action] = instructions;
 427                 }
 428
 429                 list_add_tail(&instr->node, instructions);
 430         }
 431
 432         wdat_wdt_boot_status(wdat);
 433         wdat_wdt_set_running(wdat);
 434
 435         ret = wdat_wdt_enable_reboot(wdat);
 436         if (ret)
 437                 return ret;
 438
 439         platform_set_drvdata(pdev, wdat);
 440
 441         watchdog_set_nowayout(&wdat->wdd, nowayout);
 442         return devm_watchdog_register_device(dev, &wdat->wdd);
 443 }
 444
 445 #ifdef CONFIG_PM_SLEEP
 446 static int wdat_wdt_suspend_noirq(struct device *dev)
 447 {
 448         struct wdat_wdt *wdat = dev_get_drvdata(dev);
 449         int ret;
 450
 451         if (!watchdog_active(&wdat->wdd))
 452                 return 0;
 453
 454         /*
 455          * We need to stop the watchdog if firmare is not doing it or if we
 456          * are going suspend to idle (where firmware is not involved). If
 457          * firmware is stopping the watchdog we kick it here one more time
 458          * to give it some time.
 459          */
 460         wdat->stopped = false;
 461         if (acpi_target_system_state() == ACPI_STATE_S0 ||
 462             !wdat->stopped_in_sleep) {
 463                 ret = wdat_wdt_stop(&wdat->wdd);
 464                 if (!ret)
 465                         wdat->stopped = true;
 466         } else {
 467                 ret = wdat_wdt_ping(&wdat->wdd);
 468         }
 469
 470         return ret;
 471 }
 472
 473 static int wdat_wdt_resume_noirq(struct device *dev)
 474 {
 475         struct wdat_wdt *wdat = dev_get_drvdata(dev);
 476         int ret;
 477
 478         if (!watchdog_active(&wdat->wdd))
 479                 return 0;
 480
 481         if (!wdat->stopped) {
 482                 /*
 483                  * Looks like the boot firmware reinitializes the watchdog
 484                  * before it hands off to the OS on resume from sleep so we
 485                  * stop and reprogram the watchdog here.
 486                  */
 487                 ret = wdat_wdt_stop(&wdat->wdd);
 488                 if (ret)
 489                         return ret;
 490
 491                 ret = wdat_wdt_set_timeout(&wdat->wdd, wdat->wdd.timeout);
 492                 if (ret)
 493                         return ret;
 494
 495                 ret = wdat_wdt_enable_reboot(wdat);
 496                 if (ret)
 497                         return ret;
 498
 499                 ret = wdat_wdt_ping(&wdat->wdd);
 500                 if (ret)
 501                         return ret;
 502         }
 503
 504         return wdat_wdt_start(&wdat->wdd);
 505 }
 506 #endif
 507
 508 static const struct dev_pm_ops wdat_wdt_pm_ops = {
 509         SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(wdat_wdt_suspend_noirq,
 510                                       wdat_wdt_resume_noirq)
 511 };
 512
 513 static struct platform_driver wdat_wdt_driver = {
 514         .probe = wdat_wdt_probe,
 515         .driver = {
 516                 .name = "wdat_wdt",
 517                 .pm = &wdat_wdt_pm_ops,
 518         },
 519 };
 520
 521 module_platform_driver(wdat_wdt_driver);
 522
 523 MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
 524 MODULE_DESCRIPTION("ACPI Hardware Watchdog (WDAT) driver");
 525 MODULE_LICENSE("GPL v2");
 526 MODULE_ALIAS("platform:wdat_wdt");