1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Starfive Watchdog driver 4 * 5 * Copyright (C) 2022 StarFive Technology Co., Ltd. 6 */ 7 8 #include <linux/clk.h> 9 #include <linux/iopoll.h> 10 #include <linux/module.h> 11 #include <linux/of.h> 12 #include <linux/platform_device.h> 13 #include <linux/pm_runtime.h> 14 #include <linux/reset.h> 15 #include <linux/watchdog.h> 16 17 /* JH7100 Watchdog register define */ 18 #define STARFIVE_WDT_JH7100_INTSTAUS 0x000 19 #define STARFIVE_WDT_JH7100_CONTROL 0x104 20 #define STARFIVE_WDT_JH7100_LOAD 0x108 21 #define STARFIVE_WDT_JH7100_EN 0x110 22 #define STARFIVE_WDT_JH7100_RELOAD 0x114 /* Write 0 or 1 to reload preset value */ 23 #define STARFIVE_WDT_JH7100_VALUE 0x118 24 #define STARFIVE_WDT_JH7100_INTCLR 0x120 /* 25 * [0]: Write 1 to clear interrupt 26 * [1]: 1 mean clearing and 0 mean complete 27 * [31:2]: reserved. 28 */ 29 #define STARFIVE_WDT_JH7100_LOCK 0x13c /* write 0x378f0765 to unlock */ 30 31 /* JH7110 Watchdog register define */ 32 #define STARFIVE_WDT_JH7110_LOAD 0x000 33 #define STARFIVE_WDT_JH7110_VALUE 0x004 34 #define STARFIVE_WDT_JH7110_CONTROL 0x008 /* 35 * [0]: reset enable; 36 * [1]: interrupt enable && watchdog enable 37 * [31:2]: reserved. 38 */ 39 #define STARFIVE_WDT_JH7110_INTCLR 0x00c /* clear intterupt and reload the counter */ 40 #define STARFIVE_WDT_JH7110_IMS 0x014 41 #define STARFIVE_WDT_JH7110_LOCK 0xc00 /* write 0x1ACCE551 to unlock */ 42 43 /* WDOGCONTROL */ 44 #define STARFIVE_WDT_ENABLE 0x1 45 #define STARFIVE_WDT_EN_SHIFT 0 46 #define STARFIVE_WDT_RESET_EN 0x1 47 #define STARFIVE_WDT_JH7100_RST_EN_SHIFT 0 48 #define STARFIVE_WDT_JH7110_RST_EN_SHIFT 1 49 50 /* WDOGLOCK */ 51 #define STARFIVE_WDT_JH7100_UNLOCK_KEY 0x378f0765 52 #define STARFIVE_WDT_JH7110_UNLOCK_KEY 0x1acce551 53 54 /* WDOGINTCLR */ 55 #define STARFIVE_WDT_INTCLR 0x1 56 #define STARFIVE_WDT_JH7100_INTCLR_AVA_SHIFT 1 /* Watchdog can clear interrupt when 0 */ 57 58 #define STARFIVE_WDT_MAXCNT 0xffffffff 59 #define STARFIVE_WDT_DEFAULT_TIME (15) 60 #define STARFIVE_WDT_DELAY_US 0 61 #define STARFIVE_WDT_TIMEOUT_US 10000 62 63 /* module parameter */ 64 #define STARFIVE_WDT_EARLY_ENA 0 65 66 static bool nowayout = WATCHDOG_NOWAYOUT; 67 static int heartbeat; 68 static bool early_enable = STARFIVE_WDT_EARLY_ENA; 69 70 module_param(heartbeat, int, 0); 71 module_param(early_enable, bool, 0); 72 module_param(nowayout, bool, 0); 73 74 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (default=" 75 __MODULE_STRING(STARFIVE_WDT_DEFAULT_TIME) ")"); 76 MODULE_PARM_DESC(early_enable, 77 "Watchdog is started at boot time if set to 1, default=" 78 __MODULE_STRING(STARFIVE_WDT_EARLY_ENA)); 79 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 80 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 81 82 struct starfive_wdt_variant { 83 unsigned int control; /* Watchdog Control Resgister for reset enable */ 84 unsigned int load; /* Watchdog Load register */ 85 unsigned int reload; /* Watchdog Reload Control register */ 86 unsigned int enable; /* Watchdog Enable Register */ 87 unsigned int value; /* Watchdog Counter Value Register */ 88 unsigned int int_clr; /* Watchdog Interrupt Clear Register */ 89 unsigned int unlock; /* Watchdog Lock Register */ 90 unsigned int int_status; /* Watchdog Interrupt Status Register */ 91 92 u32 unlock_key; 93 char enrst_shift; 94 char en_shift; 95 bool intclr_check; /* whether need to check it before clearing interrupt */ 96 char intclr_ava_shift; 97 bool double_timeout; /* The watchdog need twice timeout to reboot */ 98 }; 99 100 struct starfive_wdt { 101 struct watchdog_device wdd; 102 spinlock_t lock; /* spinlock for register handling */ 103 void __iomem *base; 104 struct clk *core_clk; 105 struct clk *apb_clk; 106 const struct starfive_wdt_variant *variant; 107 unsigned long freq; 108 u32 count; /* count of timeout */ 109 u32 reload; /* restore the count */ 110 }; 111 112 /* Register layout and configuration for the JH7100 */ 113 static const struct starfive_wdt_variant starfive_wdt_jh7100_variant = { 114 .control = STARFIVE_WDT_JH7100_CONTROL, 115 .load = STARFIVE_WDT_JH7100_LOAD, 116 .reload = STARFIVE_WDT_JH7100_RELOAD, 117 .enable = STARFIVE_WDT_JH7100_EN, 118 .value = STARFIVE_WDT_JH7100_VALUE, 119 .int_clr = STARFIVE_WDT_JH7100_INTCLR, 120 .unlock = STARFIVE_WDT_JH7100_LOCK, 121 .unlock_key = STARFIVE_WDT_JH7100_UNLOCK_KEY, 122 .int_status = STARFIVE_WDT_JH7100_INTSTAUS, 123 .enrst_shift = STARFIVE_WDT_JH7100_RST_EN_SHIFT, 124 .en_shift = STARFIVE_WDT_EN_SHIFT, 125 .intclr_check = true, 126 .intclr_ava_shift = STARFIVE_WDT_JH7100_INTCLR_AVA_SHIFT, 127 .double_timeout = false, 128 }; 129 130 /* Register layout and configuration for the JH7110 */ 131 static const struct starfive_wdt_variant starfive_wdt_jh7110_variant = { 132 .control = STARFIVE_WDT_JH7110_CONTROL, 133 .load = STARFIVE_WDT_JH7110_LOAD, 134 .enable = STARFIVE_WDT_JH7110_CONTROL, 135 .value = STARFIVE_WDT_JH7110_VALUE, 136 .int_clr = STARFIVE_WDT_JH7110_INTCLR, 137 .unlock = STARFIVE_WDT_JH7110_LOCK, 138 .unlock_key = STARFIVE_WDT_JH7110_UNLOCK_KEY, 139 .int_status = STARFIVE_WDT_JH7110_IMS, 140 .enrst_shift = STARFIVE_WDT_JH7110_RST_EN_SHIFT, 141 .en_shift = STARFIVE_WDT_EN_SHIFT, 142 .intclr_check = false, 143 .double_timeout = true, 144 }; 145 146 static int starfive_wdt_enable_clock(struct starfive_wdt *wdt) 147 { 148 int ret; 149 150 ret = clk_prepare_enable(wdt->apb_clk); 151 if (ret) 152 return dev_err_probe(wdt->wdd.parent, ret, "failed to enable apb clock\n"); 153 154 ret = clk_prepare_enable(wdt->core_clk); 155 if (ret) 156 return dev_err_probe(wdt->wdd.parent, ret, "failed to enable core clock\n"); 157 158 return 0; 159 } 160 161 static void starfive_wdt_disable_clock(struct starfive_wdt *wdt) 162 { 163 clk_disable_unprepare(wdt->core_clk); 164 clk_disable_unprepare(wdt->apb_clk); 165 } 166 167 static inline int starfive_wdt_get_clock(struct starfive_wdt *wdt) 168 { 169 struct device *dev = wdt->wdd.parent; 170 171 wdt->apb_clk = devm_clk_get(dev, "apb"); 172 if (IS_ERR(wdt->apb_clk)) 173 return dev_err_probe(dev, PTR_ERR(wdt->apb_clk), "failed to get apb clock\n"); 174 175 wdt->core_clk = devm_clk_get(dev, "core"); 176 if (IS_ERR(wdt->core_clk)) 177 return dev_err_probe(dev, PTR_ERR(wdt->core_clk), "failed to get core clock\n"); 178 179 return 0; 180 } 181 182 static inline int starfive_wdt_reset_init(struct device *dev) 183 { 184 struct reset_control *rsts; 185 int ret; 186 187 rsts = devm_reset_control_array_get_exclusive(dev); 188 if (IS_ERR(rsts)) 189 return dev_err_probe(dev, PTR_ERR(rsts), "failed to get resets\n"); 190 191 ret = reset_control_deassert(rsts); 192 if (ret) 193 return dev_err_probe(dev, ret, "failed to deassert resets\n"); 194 195 return 0; 196 } 197 198 static u32 starfive_wdt_ticks_to_sec(struct starfive_wdt *wdt, u32 ticks) 199 { 200 return DIV_ROUND_CLOSEST(ticks, wdt->freq); 201 } 202 203 /* Write unlock-key to unlock. Write other value to lock. */ 204 static void starfive_wdt_unlock(struct starfive_wdt *wdt) 205 __acquires(&wdt->lock) 206 { 207 spin_lock(&wdt->lock); 208 writel(wdt->variant->unlock_key, wdt->base + wdt->variant->unlock); 209 } 210 211 static void starfive_wdt_lock(struct starfive_wdt *wdt) 212 __releases(&wdt->lock) 213 { 214 writel(~wdt->variant->unlock_key, wdt->base + wdt->variant->unlock); 215 spin_unlock(&wdt->lock); 216 } 217 218 /* enable watchdog interrupt to reset/reboot */ 219 static void starfive_wdt_enable_reset(struct starfive_wdt *wdt) 220 { 221 u32 val; 222 223 val = readl(wdt->base + wdt->variant->control); 224 val |= STARFIVE_WDT_RESET_EN << wdt->variant->enrst_shift; 225 writel(val, wdt->base + wdt->variant->control); 226 } 227 228 /* interrupt status whether has been raised from the counter */ 229 static bool starfive_wdt_raise_irq_status(struct starfive_wdt *wdt) 230 { 231 return !!readl(wdt->base + wdt->variant->int_status); 232 } 233 234 /* waiting interrupt can be free to clear */ 235 static int starfive_wdt_wait_int_free(struct starfive_wdt *wdt) 236 { 237 u32 value; 238 239 return readl_poll_timeout_atomic(wdt->base + wdt->variant->int_clr, value, 240 !(value & BIT(wdt->variant->intclr_ava_shift)), 241 STARFIVE_WDT_DELAY_US, STARFIVE_WDT_TIMEOUT_US); 242 } 243 244 /* clear interrupt signal before initialization or reload */ 245 static int starfive_wdt_int_clr(struct starfive_wdt *wdt) 246 { 247 int ret; 248 249 if (wdt->variant->intclr_check) { 250 ret = starfive_wdt_wait_int_free(wdt); 251 if (ret) 252 return dev_err_probe(wdt->wdd.parent, ret, 253 "watchdog is not ready to clear interrupt.\n"); 254 } 255 writel(STARFIVE_WDT_INTCLR, wdt->base + wdt->variant->int_clr); 256 257 return 0; 258 } 259 260 static inline void starfive_wdt_set_count(struct starfive_wdt *wdt, u32 val) 261 { 262 writel(val, wdt->base + wdt->variant->load); 263 } 264 265 static inline u32 starfive_wdt_get_count(struct starfive_wdt *wdt) 266 { 267 return readl(wdt->base + wdt->variant->value); 268 } 269 270 /* enable watchdog */ 271 static inline void starfive_wdt_enable(struct starfive_wdt *wdt) 272 { 273 u32 val; 274 275 val = readl(wdt->base + wdt->variant->enable); 276 val |= STARFIVE_WDT_ENABLE << wdt->variant->en_shift; 277 writel(val, wdt->base + wdt->variant->enable); 278 } 279 280 /* disable watchdog */ 281 static inline void starfive_wdt_disable(struct starfive_wdt *wdt) 282 { 283 u32 val; 284 285 val = readl(wdt->base + wdt->variant->enable); 286 val &= ~(STARFIVE_WDT_ENABLE << wdt->variant->en_shift); 287 writel(val, wdt->base + wdt->variant->enable); 288 } 289 290 static inline void starfive_wdt_set_reload_count(struct starfive_wdt *wdt, u32 count) 291 { 292 starfive_wdt_set_count(wdt, count); 293 294 /* 7100 need set any value to reload register and could reload value to counter */ 295 if (wdt->variant->reload) 296 writel(0x1, wdt->base + wdt->variant->reload); 297 } 298 299 static unsigned int starfive_wdt_max_timeout(struct starfive_wdt *wdt) 300 { 301 if (wdt->variant->double_timeout) 302 return DIV_ROUND_UP(STARFIVE_WDT_MAXCNT, (wdt->freq / 2)) - 1; 303 304 return DIV_ROUND_UP(STARFIVE_WDT_MAXCNT, wdt->freq) - 1; 305 } 306 307 static unsigned int starfive_wdt_get_timeleft(struct watchdog_device *wdd) 308 { 309 struct starfive_wdt *wdt = watchdog_get_drvdata(wdd); 310 u32 count; 311 312 /* 313 * If the watchdog takes twice timeout and set half count value, 314 * timeleft value should add the count value before first timeout. 315 */ 316 count = starfive_wdt_get_count(wdt); 317 if (wdt->variant->double_timeout && !starfive_wdt_raise_irq_status(wdt)) 318 count += wdt->count; 319 320 return starfive_wdt_ticks_to_sec(wdt, count); 321 } 322 323 static int starfive_wdt_keepalive(struct watchdog_device *wdd) 324 { 325 struct starfive_wdt *wdt = watchdog_get_drvdata(wdd); 326 int ret; 327 328 starfive_wdt_unlock(wdt); 329 ret = starfive_wdt_int_clr(wdt); 330 if (ret) 331 goto exit; 332 333 starfive_wdt_set_reload_count(wdt, wdt->count); 334 335 exit: 336 /* exit with releasing spinlock and locking registers */ 337 starfive_wdt_lock(wdt); 338 return ret; 339 } 340 341 static int starfive_wdt_start(struct starfive_wdt *wdt) 342 { 343 int ret; 344 345 starfive_wdt_unlock(wdt); 346 /* disable watchdog, to be safe */ 347 starfive_wdt_disable(wdt); 348 349 starfive_wdt_enable_reset(wdt); 350 ret = starfive_wdt_int_clr(wdt); 351 if (ret) 352 goto exit; 353 354 starfive_wdt_set_count(wdt, wdt->count); 355 starfive_wdt_enable(wdt); 356 357 exit: 358 starfive_wdt_lock(wdt); 359 return ret; 360 } 361 362 static void starfive_wdt_stop(struct starfive_wdt *wdt) 363 { 364 starfive_wdt_unlock(wdt); 365 starfive_wdt_disable(wdt); 366 starfive_wdt_lock(wdt); 367 } 368 369 static int starfive_wdt_pm_start(struct watchdog_device *wdd) 370 { 371 struct starfive_wdt *wdt = watchdog_get_drvdata(wdd); 372 int ret = pm_runtime_get_sync(wdd->parent); 373 374 if (ret < 0) 375 return ret; 376 377 return starfive_wdt_start(wdt); 378 } 379 380 static int starfive_wdt_pm_stop(struct watchdog_device *wdd) 381 { 382 struct starfive_wdt *wdt = watchdog_get_drvdata(wdd); 383 384 starfive_wdt_stop(wdt); 385 return pm_runtime_put_sync(wdd->parent); 386 } 387 388 static int starfive_wdt_set_timeout(struct watchdog_device *wdd, 389 unsigned int timeout) 390 { 391 struct starfive_wdt *wdt = watchdog_get_drvdata(wdd); 392 unsigned long count = timeout * wdt->freq; 393 394 /* some watchdogs take two timeouts to reset */ 395 if (wdt->variant->double_timeout) 396 count /= 2; 397 398 wdt->count = count; 399 wdd->timeout = timeout; 400 401 starfive_wdt_unlock(wdt); 402 starfive_wdt_disable(wdt); 403 starfive_wdt_set_reload_count(wdt, wdt->count); 404 starfive_wdt_enable(wdt); 405 starfive_wdt_lock(wdt); 406 407 return 0; 408 } 409 410 #define STARFIVE_WDT_OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE) 411 412 static const struct watchdog_info starfive_wdt_info = { 413 .options = STARFIVE_WDT_OPTIONS, 414 .identity = "StarFive Watchdog", 415 }; 416 417 static const struct watchdog_ops starfive_wdt_ops = { 418 .owner = THIS_MODULE, 419 .start = starfive_wdt_pm_start, 420 .stop = starfive_wdt_pm_stop, 421 .ping = starfive_wdt_keepalive, 422 .set_timeout = starfive_wdt_set_timeout, 423 .get_timeleft = starfive_wdt_get_timeleft, 424 }; 425 426 static int starfive_wdt_probe(struct platform_device *pdev) 427 { 428 struct starfive_wdt *wdt; 429 int ret; 430 431 wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); 432 if (!wdt) 433 return -ENOMEM; 434 435 wdt->base = devm_platform_ioremap_resource(pdev, 0); 436 if (IS_ERR(wdt->base)) 437 return dev_err_probe(&pdev->dev, PTR_ERR(wdt->base), "error mapping registers\n"); 438 439 wdt->wdd.parent = &pdev->dev; 440 ret = starfive_wdt_get_clock(wdt); 441 if (ret) 442 return ret; 443 444 platform_set_drvdata(pdev, wdt); 445 pm_runtime_enable(&pdev->dev); 446 if (pm_runtime_enabled(&pdev->dev)) { 447 ret = pm_runtime_get_sync(&pdev->dev); 448 if (ret < 0) 449 return ret; 450 } else { 451 /* runtime PM is disabled but clocks need to be enabled */ 452 ret = starfive_wdt_enable_clock(wdt); 453 if (ret) 454 return ret; 455 } 456 457 ret = starfive_wdt_reset_init(&pdev->dev); 458 if (ret) 459 goto err_exit; 460 461 watchdog_set_drvdata(&wdt->wdd, wdt); 462 wdt->wdd.info = &starfive_wdt_info; 463 wdt->wdd.ops = &starfive_wdt_ops; 464 wdt->variant = of_device_get_match_data(&pdev->dev); 465 spin_lock_init(&wdt->lock); 466 467 wdt->freq = clk_get_rate(wdt->core_clk); 468 if (!wdt->freq) { 469 dev_err(&pdev->dev, "get clock rate failed.\n"); 470 ret = -EINVAL; 471 goto err_exit; 472 } 473 474 wdt->wdd.min_timeout = 1; 475 wdt->wdd.max_timeout = starfive_wdt_max_timeout(wdt); 476 wdt->wdd.timeout = STARFIVE_WDT_DEFAULT_TIME; 477 watchdog_init_timeout(&wdt->wdd, heartbeat, &pdev->dev); 478 starfive_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout); 479 480 watchdog_set_nowayout(&wdt->wdd, nowayout); 481 watchdog_stop_on_reboot(&wdt->wdd); 482 watchdog_stop_on_unregister(&wdt->wdd); 483 484 if (early_enable) { 485 ret = starfive_wdt_start(wdt); 486 if (ret) 487 goto err_exit; 488 set_bit(WDOG_HW_RUNNING, &wdt->wdd.status); 489 } else { 490 starfive_wdt_stop(wdt); 491 } 492 493 ret = watchdog_register_device(&wdt->wdd); 494 if (ret) 495 goto err_exit; 496 497 if (!early_enable) 498 pm_runtime_put_sync(&pdev->dev); 499 500 return 0; 501 502 err_exit: 503 starfive_wdt_disable_clock(wdt); 504 pm_runtime_disable(&pdev->dev); 505 506 return ret; 507 } 508 509 static int starfive_wdt_remove(struct platform_device *pdev) 510 { 511 struct starfive_wdt *wdt = platform_get_drvdata(pdev); 512 513 starfive_wdt_stop(wdt); 514 watchdog_unregister_device(&wdt->wdd); 515 516 if (pm_runtime_enabled(&pdev->dev)) 517 pm_runtime_disable(&pdev->dev); 518 else 519 /* disable clock without PM */ 520 starfive_wdt_disable_clock(wdt); 521 522 return 0; 523 } 524 525 static void starfive_wdt_shutdown(struct platform_device *pdev) 526 { 527 struct starfive_wdt *wdt = platform_get_drvdata(pdev); 528 529 starfive_wdt_pm_stop(&wdt->wdd); 530 } 531 532 static int starfive_wdt_suspend(struct device *dev) 533 { 534 struct starfive_wdt *wdt = dev_get_drvdata(dev); 535 536 /* Save watchdog state, and turn it off. */ 537 wdt->reload = starfive_wdt_get_count(wdt); 538 539 /* Note that WTCNT doesn't need to be saved. */ 540 starfive_wdt_stop(wdt); 541 542 return pm_runtime_force_suspend(dev); 543 } 544 545 static int starfive_wdt_resume(struct device *dev) 546 { 547 struct starfive_wdt *wdt = dev_get_drvdata(dev); 548 int ret; 549 550 ret = pm_runtime_force_resume(dev); 551 if (ret) 552 return ret; 553 554 starfive_wdt_unlock(wdt); 555 /* Restore watchdog state. */ 556 starfive_wdt_set_reload_count(wdt, wdt->reload); 557 starfive_wdt_lock(wdt); 558 559 return starfive_wdt_start(wdt); 560 } 561 562 static int starfive_wdt_runtime_suspend(struct device *dev) 563 { 564 struct starfive_wdt *wdt = dev_get_drvdata(dev); 565 566 starfive_wdt_disable_clock(wdt); 567 568 return 0; 569 } 570 571 static int starfive_wdt_runtime_resume(struct device *dev) 572 { 573 struct starfive_wdt *wdt = dev_get_drvdata(dev); 574 575 return starfive_wdt_enable_clock(wdt); 576 } 577 578 static const struct dev_pm_ops starfive_wdt_pm_ops = { 579 RUNTIME_PM_OPS(starfive_wdt_runtime_suspend, starfive_wdt_runtime_resume, NULL) 580 SYSTEM_SLEEP_PM_OPS(starfive_wdt_suspend, starfive_wdt_resume) 581 }; 582 583 static const struct of_device_id starfive_wdt_match[] = { 584 { .compatible = "starfive,jh7100-wdt", .data = &starfive_wdt_jh7100_variant }, 585 { .compatible = "starfive,jh7110-wdt", .data = &starfive_wdt_jh7110_variant }, 586 { /* sentinel */ } 587 }; 588 MODULE_DEVICE_TABLE(of, starfive_wdt_match); 589 590 static struct platform_driver starfive_wdt_driver = { 591 .probe = starfive_wdt_probe, 592 .remove = starfive_wdt_remove, 593 .shutdown = starfive_wdt_shutdown, 594 .driver = { 595 .name = "starfive-wdt", 596 .pm = pm_ptr(&starfive_wdt_pm_ops), 597 .of_match_table = starfive_wdt_match, 598 }, 599 }; 600 module_platform_driver(starfive_wdt_driver); 601 602 MODULE_AUTHOR("Xingyu Wu <xingyu.wu@starfivetech.com>"); 603 MODULE_AUTHOR("Samin Guo <samin.guo@starfivetech.com>"); 604 MODULE_DESCRIPTION("StarFive Watchdog Device Driver"); 605 MODULE_LICENSE("GPL"); 606