1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright 2010-2011 Picochip Ltd., Jamie Iles 4 * https://www.picochip.com 5 * 6 * This file implements a driver for the Synopsys DesignWare watchdog device 7 * in the many subsystems. The watchdog has 16 different timeout periods 8 * and these are a function of the input clock frequency. 9 * 10 * The DesignWare watchdog cannot be stopped once it has been started so we 11 * do not implement a stop function. The watchdog core will continue to send 12 * heartbeat requests after the watchdog device has been closed. 13 */ 14 15 #include <linux/bitops.h> 16 #include <linux/limits.h> 17 #include <linux/kernel.h> 18 #include <linux/clk.h> 19 #include <linux/delay.h> 20 #include <linux/err.h> 21 #include <linux/io.h> 22 #include <linux/kernel.h> 23 #include <linux/module.h> 24 #include <linux/moduleparam.h> 25 #include <linux/interrupt.h> 26 #include <linux/of.h> 27 #include <linux/pm.h> 28 #include <linux/platform_device.h> 29 #include <linux/reset.h> 30 #include <linux/watchdog.h> 31 #include <linux/debugfs.h> 32 33 #define WDOG_CONTROL_REG_OFFSET 0x00 34 #define WDOG_CONTROL_REG_WDT_EN_MASK 0x01 35 #define WDOG_CONTROL_REG_RESP_MODE_MASK 0x02 36 #define WDOG_TIMEOUT_RANGE_REG_OFFSET 0x04 37 #define WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT 4 38 #define WDOG_CURRENT_COUNT_REG_OFFSET 0x08 39 #define WDOG_COUNTER_RESTART_REG_OFFSET 0x0c 40 #define WDOG_COUNTER_RESTART_KICK_VALUE 0x76 41 #define WDOG_INTERRUPT_STATUS_REG_OFFSET 0x10 42 #define WDOG_INTERRUPT_CLEAR_REG_OFFSET 0x14 43 #define WDOG_COMP_PARAMS_5_REG_OFFSET 0xe4 44 #define WDOG_COMP_PARAMS_4_REG_OFFSET 0xe8 45 #define WDOG_COMP_PARAMS_3_REG_OFFSET 0xec 46 #define WDOG_COMP_PARAMS_2_REG_OFFSET 0xf0 47 #define WDOG_COMP_PARAMS_1_REG_OFFSET 0xf4 48 #define WDOG_COMP_PARAMS_1_USE_FIX_TOP BIT(6) 49 #define WDOG_COMP_VERSION_REG_OFFSET 0xf8 50 #define WDOG_COMP_TYPE_REG_OFFSET 0xfc 51 52 /* There are sixteen TOPs (timeout periods) that can be set in the watchdog. */ 53 #define DW_WDT_NUM_TOPS 16 54 #define DW_WDT_FIX_TOP(_idx) (1U << (16 + _idx)) 55 56 #define DW_WDT_DEFAULT_SECONDS 30 57 58 static const u32 dw_wdt_fix_tops[DW_WDT_NUM_TOPS] = { 59 DW_WDT_FIX_TOP(0), DW_WDT_FIX_TOP(1), DW_WDT_FIX_TOP(2), 60 DW_WDT_FIX_TOP(3), DW_WDT_FIX_TOP(4), DW_WDT_FIX_TOP(5), 61 DW_WDT_FIX_TOP(6), DW_WDT_FIX_TOP(7), DW_WDT_FIX_TOP(8), 62 DW_WDT_FIX_TOP(9), DW_WDT_FIX_TOP(10), DW_WDT_FIX_TOP(11), 63 DW_WDT_FIX_TOP(12), DW_WDT_FIX_TOP(13), DW_WDT_FIX_TOP(14), 64 DW_WDT_FIX_TOP(15) 65 }; 66 67 static bool nowayout = WATCHDOG_NOWAYOUT; 68 module_param(nowayout, bool, 0); 69 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " 70 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 71 72 enum dw_wdt_rmod { 73 DW_WDT_RMOD_RESET = 1, 74 DW_WDT_RMOD_IRQ = 2 75 }; 76 77 struct dw_wdt_timeout { 78 u32 top_val; 79 unsigned int sec; 80 unsigned int msec; 81 }; 82 83 struct dw_wdt { 84 void __iomem *regs; 85 struct clk *clk; 86 struct clk *pclk; 87 unsigned long rate; 88 enum dw_wdt_rmod rmod; 89 struct dw_wdt_timeout timeouts[DW_WDT_NUM_TOPS]; 90 struct watchdog_device wdd; 91 struct reset_control *rst; 92 /* Save/restore */ 93 u32 control; 94 u32 timeout; 95 96 #ifdef CONFIG_DEBUG_FS 97 struct dentry *dbgfs_dir; 98 #endif 99 }; 100 101 #define to_dw_wdt(wdd) container_of(wdd, struct dw_wdt, wdd) 102 103 static inline int dw_wdt_is_enabled(struct dw_wdt *dw_wdt) 104 { 105 return readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET) & 106 WDOG_CONTROL_REG_WDT_EN_MASK; 107 } 108 109 static void dw_wdt_update_mode(struct dw_wdt *dw_wdt, enum dw_wdt_rmod rmod) 110 { 111 u32 val; 112 113 val = readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET); 114 if (rmod == DW_WDT_RMOD_IRQ) 115 val |= WDOG_CONTROL_REG_RESP_MODE_MASK; 116 else 117 val &= ~WDOG_CONTROL_REG_RESP_MODE_MASK; 118 writel(val, dw_wdt->regs + WDOG_CONTROL_REG_OFFSET); 119 120 dw_wdt->rmod = rmod; 121 } 122 123 static unsigned int dw_wdt_find_best_top(struct dw_wdt *dw_wdt, 124 unsigned int timeout, u32 *top_val) 125 { 126 int idx; 127 128 /* 129 * Find a TOP with timeout greater or equal to the requested number. 130 * Note we'll select a TOP with maximum timeout if the requested 131 * timeout couldn't be reached. 132 */ 133 for (idx = 0; idx < DW_WDT_NUM_TOPS; ++idx) { 134 if (dw_wdt->timeouts[idx].sec >= timeout) 135 break; 136 } 137 138 if (idx == DW_WDT_NUM_TOPS) 139 --idx; 140 141 *top_val = dw_wdt->timeouts[idx].top_val; 142 143 return dw_wdt->timeouts[idx].sec; 144 } 145 146 static unsigned int dw_wdt_get_min_timeout(struct dw_wdt *dw_wdt) 147 { 148 int idx; 149 150 /* 151 * We'll find a timeout greater or equal to one second anyway because 152 * the driver probe would have failed if there was none. 153 */ 154 for (idx = 0; idx < DW_WDT_NUM_TOPS; ++idx) { 155 if (dw_wdt->timeouts[idx].sec) 156 break; 157 } 158 159 return dw_wdt->timeouts[idx].sec; 160 } 161 162 static unsigned int dw_wdt_get_max_timeout_ms(struct dw_wdt *dw_wdt) 163 { 164 struct dw_wdt_timeout *timeout = &dw_wdt->timeouts[DW_WDT_NUM_TOPS - 1]; 165 u64 msec; 166 167 msec = (u64)timeout->sec * MSEC_PER_SEC + timeout->msec; 168 169 return msec < UINT_MAX ? msec : UINT_MAX; 170 } 171 172 static unsigned int dw_wdt_get_timeout(struct dw_wdt *dw_wdt) 173 { 174 int top_val = readl(dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET) & 0xF; 175 int idx; 176 177 for (idx = 0; idx < DW_WDT_NUM_TOPS; ++idx) { 178 if (dw_wdt->timeouts[idx].top_val == top_val) 179 break; 180 } 181 182 /* 183 * In IRQ mode due to the two stages counter, the actual timeout is 184 * twice greater than the TOP setting. 185 */ 186 return dw_wdt->timeouts[idx].sec * dw_wdt->rmod; 187 } 188 189 static int dw_wdt_ping(struct watchdog_device *wdd) 190 { 191 struct dw_wdt *dw_wdt = to_dw_wdt(wdd); 192 193 writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt->regs + 194 WDOG_COUNTER_RESTART_REG_OFFSET); 195 196 return 0; 197 } 198 199 static int dw_wdt_set_timeout(struct watchdog_device *wdd, unsigned int top_s) 200 { 201 struct dw_wdt *dw_wdt = to_dw_wdt(wdd); 202 unsigned int timeout; 203 u32 top_val; 204 205 /* 206 * Note IRQ mode being enabled means having a non-zero pre-timeout 207 * setup. In this case we try to find a TOP as close to the half of the 208 * requested timeout as possible since DW Watchdog IRQ mode is designed 209 * in two stages way - first timeout rises the pre-timeout interrupt, 210 * second timeout performs the system reset. So basically the effective 211 * watchdog-caused reset happens after two watchdog TOPs elapsed. 212 */ 213 timeout = dw_wdt_find_best_top(dw_wdt, DIV_ROUND_UP(top_s, dw_wdt->rmod), 214 &top_val); 215 if (dw_wdt->rmod == DW_WDT_RMOD_IRQ) 216 wdd->pretimeout = timeout; 217 else 218 wdd->pretimeout = 0; 219 220 /* 221 * Set the new value in the watchdog. Some versions of dw_wdt 222 * have have TOPINIT in the TIMEOUT_RANGE register (as per 223 * CP_WDT_DUAL_TOP in WDT_COMP_PARAMS_1). On those we 224 * effectively get a pat of the watchdog right here. 225 */ 226 writel(top_val | top_val << WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT, 227 dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET); 228 229 /* Kick new TOP value into the watchdog counter if activated. */ 230 if (watchdog_active(wdd)) 231 dw_wdt_ping(wdd); 232 233 /* 234 * In case users set bigger timeout value than HW can support, 235 * kernel(watchdog_dev.c) helps to feed watchdog before 236 * wdd->max_hw_heartbeat_ms 237 */ 238 if (top_s * 1000 <= wdd->max_hw_heartbeat_ms) 239 wdd->timeout = timeout * dw_wdt->rmod; 240 else 241 wdd->timeout = top_s; 242 243 return 0; 244 } 245 246 static int dw_wdt_set_pretimeout(struct watchdog_device *wdd, unsigned int req) 247 { 248 struct dw_wdt *dw_wdt = to_dw_wdt(wdd); 249 250 /* 251 * We ignore actual value of the timeout passed from user-space 252 * using it as a flag whether the pretimeout functionality is intended 253 * to be activated. 254 */ 255 dw_wdt_update_mode(dw_wdt, req ? DW_WDT_RMOD_IRQ : DW_WDT_RMOD_RESET); 256 dw_wdt_set_timeout(wdd, wdd->timeout); 257 258 return 0; 259 } 260 261 static void dw_wdt_arm_system_reset(struct dw_wdt *dw_wdt) 262 { 263 u32 val = readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET); 264 265 /* Disable/enable interrupt mode depending on the RMOD flag. */ 266 if (dw_wdt->rmod == DW_WDT_RMOD_IRQ) 267 val |= WDOG_CONTROL_REG_RESP_MODE_MASK; 268 else 269 val &= ~WDOG_CONTROL_REG_RESP_MODE_MASK; 270 /* Enable watchdog. */ 271 val |= WDOG_CONTROL_REG_WDT_EN_MASK; 272 writel(val, dw_wdt->regs + WDOG_CONTROL_REG_OFFSET); 273 } 274 275 static int dw_wdt_start(struct watchdog_device *wdd) 276 { 277 struct dw_wdt *dw_wdt = to_dw_wdt(wdd); 278 279 dw_wdt_set_timeout(wdd, wdd->timeout); 280 dw_wdt_ping(&dw_wdt->wdd); 281 dw_wdt_arm_system_reset(dw_wdt); 282 283 return 0; 284 } 285 286 static int dw_wdt_stop(struct watchdog_device *wdd) 287 { 288 struct dw_wdt *dw_wdt = to_dw_wdt(wdd); 289 290 if (!dw_wdt->rst) { 291 set_bit(WDOG_HW_RUNNING, &wdd->status); 292 return 0; 293 } 294 295 reset_control_assert(dw_wdt->rst); 296 reset_control_deassert(dw_wdt->rst); 297 298 return 0; 299 } 300 301 static int dw_wdt_restart(struct watchdog_device *wdd, 302 unsigned long action, void *data) 303 { 304 struct dw_wdt *dw_wdt = to_dw_wdt(wdd); 305 306 writel(0, dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET); 307 dw_wdt_update_mode(dw_wdt, DW_WDT_RMOD_RESET); 308 if (dw_wdt_is_enabled(dw_wdt)) 309 writel(WDOG_COUNTER_RESTART_KICK_VALUE, 310 dw_wdt->regs + WDOG_COUNTER_RESTART_REG_OFFSET); 311 else 312 dw_wdt_arm_system_reset(dw_wdt); 313 314 /* wait for reset to assert... */ 315 mdelay(500); 316 317 return 0; 318 } 319 320 static unsigned int dw_wdt_get_timeleft(struct watchdog_device *wdd) 321 { 322 struct dw_wdt *dw_wdt = to_dw_wdt(wdd); 323 unsigned int sec; 324 u32 val; 325 326 val = readl(dw_wdt->regs + WDOG_CURRENT_COUNT_REG_OFFSET); 327 sec = val / dw_wdt->rate; 328 329 if (dw_wdt->rmod == DW_WDT_RMOD_IRQ) { 330 val = readl(dw_wdt->regs + WDOG_INTERRUPT_STATUS_REG_OFFSET); 331 if (!val) 332 sec += wdd->pretimeout; 333 } 334 335 return sec; 336 } 337 338 static const struct watchdog_info dw_wdt_ident = { 339 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | 340 WDIOF_MAGICCLOSE, 341 .identity = "Synopsys DesignWare Watchdog", 342 }; 343 344 static const struct watchdog_info dw_wdt_pt_ident = { 345 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | 346 WDIOF_PRETIMEOUT | WDIOF_MAGICCLOSE, 347 .identity = "Synopsys DesignWare Watchdog", 348 }; 349 350 static const struct watchdog_ops dw_wdt_ops = { 351 .owner = THIS_MODULE, 352 .start = dw_wdt_start, 353 .stop = dw_wdt_stop, 354 .ping = dw_wdt_ping, 355 .set_timeout = dw_wdt_set_timeout, 356 .set_pretimeout = dw_wdt_set_pretimeout, 357 .get_timeleft = dw_wdt_get_timeleft, 358 .restart = dw_wdt_restart, 359 }; 360 361 static irqreturn_t dw_wdt_irq(int irq, void *devid) 362 { 363 struct dw_wdt *dw_wdt = devid; 364 u32 val; 365 366 /* 367 * We don't clear the IRQ status. It's supposed to be done by the 368 * following ping operations. 369 */ 370 val = readl(dw_wdt->regs + WDOG_INTERRUPT_STATUS_REG_OFFSET); 371 if (!val) 372 return IRQ_NONE; 373 374 watchdog_notify_pretimeout(&dw_wdt->wdd); 375 376 return IRQ_HANDLED; 377 } 378 379 #ifdef CONFIG_PM_SLEEP 380 static int dw_wdt_suspend(struct device *dev) 381 { 382 struct dw_wdt *dw_wdt = dev_get_drvdata(dev); 383 384 dw_wdt->control = readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET); 385 dw_wdt->timeout = readl(dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET); 386 387 clk_disable_unprepare(dw_wdt->pclk); 388 clk_disable_unprepare(dw_wdt->clk); 389 390 return 0; 391 } 392 393 static int dw_wdt_resume(struct device *dev) 394 { 395 struct dw_wdt *dw_wdt = dev_get_drvdata(dev); 396 int err = clk_prepare_enable(dw_wdt->clk); 397 398 if (err) 399 return err; 400 401 err = clk_prepare_enable(dw_wdt->pclk); 402 if (err) { 403 clk_disable_unprepare(dw_wdt->clk); 404 return err; 405 } 406 407 writel(dw_wdt->timeout, dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET); 408 writel(dw_wdt->control, dw_wdt->regs + WDOG_CONTROL_REG_OFFSET); 409 410 dw_wdt_ping(&dw_wdt->wdd); 411 412 return 0; 413 } 414 #endif /* CONFIG_PM_SLEEP */ 415 416 static SIMPLE_DEV_PM_OPS(dw_wdt_pm_ops, dw_wdt_suspend, dw_wdt_resume); 417 418 /* 419 * In case if DW WDT IP core is synthesized with fixed TOP feature disabled the 420 * TOPs array can be arbitrary ordered with nearly any sixteen uint numbers 421 * depending on the system engineer imagination. The next method handles the 422 * passed TOPs array to pre-calculate the effective timeouts and to sort the 423 * TOP items out in the ascending order with respect to the timeouts. 424 */ 425 426 static void dw_wdt_handle_tops(struct dw_wdt *dw_wdt, const u32 *tops) 427 { 428 struct dw_wdt_timeout tout, *dst; 429 int val, tidx; 430 u64 msec; 431 432 /* 433 * We walk over the passed TOPs array and calculate corresponding 434 * timeouts in seconds and milliseconds. The milliseconds granularity 435 * is needed to distinguish the TOPs with very close timeouts and to 436 * set the watchdog max heartbeat setting further. 437 */ 438 for (val = 0; val < DW_WDT_NUM_TOPS; ++val) { 439 tout.top_val = val; 440 tout.sec = tops[val] / dw_wdt->rate; 441 msec = (u64)tops[val] * MSEC_PER_SEC; 442 do_div(msec, dw_wdt->rate); 443 tout.msec = msec - ((u64)tout.sec * MSEC_PER_SEC); 444 445 /* 446 * Find a suitable place for the current TOP in the timeouts 447 * array so that the list is remained in the ascending order. 448 */ 449 for (tidx = 0; tidx < val; ++tidx) { 450 dst = &dw_wdt->timeouts[tidx]; 451 if (tout.sec > dst->sec || (tout.sec == dst->sec && 452 tout.msec >= dst->msec)) 453 continue; 454 else 455 swap(*dst, tout); 456 } 457 458 dw_wdt->timeouts[val] = tout; 459 } 460 } 461 462 static int dw_wdt_init_timeouts(struct dw_wdt *dw_wdt, struct device *dev) 463 { 464 u32 data, of_tops[DW_WDT_NUM_TOPS]; 465 const u32 *tops; 466 int ret; 467 468 /* 469 * Retrieve custom or fixed counter values depending on the 470 * WDT_USE_FIX_TOP flag found in the component specific parameters 471 * #1 register. 472 */ 473 data = readl(dw_wdt->regs + WDOG_COMP_PARAMS_1_REG_OFFSET); 474 if (data & WDOG_COMP_PARAMS_1_USE_FIX_TOP) { 475 tops = dw_wdt_fix_tops; 476 } else { 477 ret = of_property_read_variable_u32_array(dev_of_node(dev), 478 "snps,watchdog-tops", of_tops, DW_WDT_NUM_TOPS, 479 DW_WDT_NUM_TOPS); 480 if (ret < 0) { 481 dev_warn(dev, "No valid TOPs array specified\n"); 482 tops = dw_wdt_fix_tops; 483 } else { 484 tops = of_tops; 485 } 486 } 487 488 /* Convert the specified TOPs into an array of watchdog timeouts. */ 489 dw_wdt_handle_tops(dw_wdt, tops); 490 if (!dw_wdt->timeouts[DW_WDT_NUM_TOPS - 1].sec) { 491 dev_err(dev, "No any valid TOP detected\n"); 492 return -EINVAL; 493 } 494 495 return 0; 496 } 497 498 #ifdef CONFIG_DEBUG_FS 499 500 #define DW_WDT_DBGFS_REG(_name, _off) \ 501 { \ 502 .name = _name, \ 503 .offset = _off \ 504 } 505 506 static const struct debugfs_reg32 dw_wdt_dbgfs_regs[] = { 507 DW_WDT_DBGFS_REG("cr", WDOG_CONTROL_REG_OFFSET), 508 DW_WDT_DBGFS_REG("torr", WDOG_TIMEOUT_RANGE_REG_OFFSET), 509 DW_WDT_DBGFS_REG("ccvr", WDOG_CURRENT_COUNT_REG_OFFSET), 510 DW_WDT_DBGFS_REG("crr", WDOG_COUNTER_RESTART_REG_OFFSET), 511 DW_WDT_DBGFS_REG("stat", WDOG_INTERRUPT_STATUS_REG_OFFSET), 512 DW_WDT_DBGFS_REG("param5", WDOG_COMP_PARAMS_5_REG_OFFSET), 513 DW_WDT_DBGFS_REG("param4", WDOG_COMP_PARAMS_4_REG_OFFSET), 514 DW_WDT_DBGFS_REG("param3", WDOG_COMP_PARAMS_3_REG_OFFSET), 515 DW_WDT_DBGFS_REG("param2", WDOG_COMP_PARAMS_2_REG_OFFSET), 516 DW_WDT_DBGFS_REG("param1", WDOG_COMP_PARAMS_1_REG_OFFSET), 517 DW_WDT_DBGFS_REG("version", WDOG_COMP_VERSION_REG_OFFSET), 518 DW_WDT_DBGFS_REG("type", WDOG_COMP_TYPE_REG_OFFSET) 519 }; 520 521 static void dw_wdt_dbgfs_init(struct dw_wdt *dw_wdt) 522 { 523 struct device *dev = dw_wdt->wdd.parent; 524 struct debugfs_regset32 *regset; 525 526 regset = devm_kzalloc(dev, sizeof(*regset), GFP_KERNEL); 527 if (!regset) 528 return; 529 530 regset->regs = dw_wdt_dbgfs_regs; 531 regset->nregs = ARRAY_SIZE(dw_wdt_dbgfs_regs); 532 regset->base = dw_wdt->regs; 533 534 dw_wdt->dbgfs_dir = debugfs_create_dir(dev_name(dev), NULL); 535 536 debugfs_create_regset32("registers", 0444, dw_wdt->dbgfs_dir, regset); 537 } 538 539 static void dw_wdt_dbgfs_clear(struct dw_wdt *dw_wdt) 540 { 541 debugfs_remove_recursive(dw_wdt->dbgfs_dir); 542 } 543 544 #else /* !CONFIG_DEBUG_FS */ 545 546 static void dw_wdt_dbgfs_init(struct dw_wdt *dw_wdt) {} 547 static void dw_wdt_dbgfs_clear(struct dw_wdt *dw_wdt) {} 548 549 #endif /* !CONFIG_DEBUG_FS */ 550 551 static int dw_wdt_drv_probe(struct platform_device *pdev) 552 { 553 struct device *dev = &pdev->dev; 554 struct watchdog_device *wdd; 555 struct dw_wdt *dw_wdt; 556 int ret; 557 558 dw_wdt = devm_kzalloc(dev, sizeof(*dw_wdt), GFP_KERNEL); 559 if (!dw_wdt) 560 return -ENOMEM; 561 562 dw_wdt->regs = devm_platform_ioremap_resource(pdev, 0); 563 if (IS_ERR(dw_wdt->regs)) 564 return PTR_ERR(dw_wdt->regs); 565 566 /* 567 * Try to request the watchdog dedicated timer clock source. It must 568 * be supplied if asynchronous mode is enabled. Otherwise fallback 569 * to the common timer/bus clocks configuration, in which the very 570 * first found clock supply both timer and APB signals. 571 */ 572 dw_wdt->clk = devm_clk_get(dev, "tclk"); 573 if (IS_ERR(dw_wdt->clk)) { 574 dw_wdt->clk = devm_clk_get(dev, NULL); 575 if (IS_ERR(dw_wdt->clk)) 576 return PTR_ERR(dw_wdt->clk); 577 } 578 579 ret = clk_prepare_enable(dw_wdt->clk); 580 if (ret) 581 return ret; 582 583 dw_wdt->rate = clk_get_rate(dw_wdt->clk); 584 if (dw_wdt->rate == 0) { 585 ret = -EINVAL; 586 goto out_disable_clk; 587 } 588 589 /* 590 * Request APB clock if device is configured with async clocks mode. 591 * In this case both tclk and pclk clocks are supposed to be specified. 592 * Alas we can't know for sure whether async mode was really activated, 593 * so the pclk phandle reference is left optional. If it couldn't be 594 * found we consider the device configured in synchronous clocks mode. 595 */ 596 dw_wdt->pclk = devm_clk_get_optional(dev, "pclk"); 597 if (IS_ERR(dw_wdt->pclk)) { 598 ret = PTR_ERR(dw_wdt->pclk); 599 goto out_disable_clk; 600 } 601 602 ret = clk_prepare_enable(dw_wdt->pclk); 603 if (ret) 604 goto out_disable_clk; 605 606 dw_wdt->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL); 607 if (IS_ERR(dw_wdt->rst)) { 608 ret = PTR_ERR(dw_wdt->rst); 609 goto out_disable_pclk; 610 } 611 612 /* Enable normal reset without pre-timeout by default. */ 613 dw_wdt_update_mode(dw_wdt, DW_WDT_RMOD_RESET); 614 615 /* 616 * Pre-timeout IRQ is optional, since some hardware may lack support 617 * of it. Note we must request rising-edge IRQ, since the lane is left 618 * pending either until the next watchdog kick event or up to the 619 * system reset. 620 */ 621 ret = platform_get_irq_optional(pdev, 0); 622 if (ret > 0) { 623 ret = devm_request_irq(dev, ret, dw_wdt_irq, 624 IRQF_SHARED | IRQF_TRIGGER_RISING, 625 pdev->name, dw_wdt); 626 if (ret) 627 goto out_disable_pclk; 628 629 dw_wdt->wdd.info = &dw_wdt_pt_ident; 630 } else { 631 if (ret == -EPROBE_DEFER) 632 goto out_disable_pclk; 633 634 dw_wdt->wdd.info = &dw_wdt_ident; 635 } 636 637 reset_control_deassert(dw_wdt->rst); 638 639 ret = dw_wdt_init_timeouts(dw_wdt, dev); 640 if (ret) 641 goto out_disable_clk; 642 643 wdd = &dw_wdt->wdd; 644 wdd->ops = &dw_wdt_ops; 645 wdd->min_timeout = dw_wdt_get_min_timeout(dw_wdt); 646 wdd->max_hw_heartbeat_ms = dw_wdt_get_max_timeout_ms(dw_wdt); 647 wdd->parent = dev; 648 649 watchdog_set_drvdata(wdd, dw_wdt); 650 watchdog_set_nowayout(wdd, nowayout); 651 watchdog_init_timeout(wdd, 0, dev); 652 653 /* 654 * If the watchdog is already running, use its already configured 655 * timeout. Otherwise use the default or the value provided through 656 * devicetree. 657 */ 658 if (dw_wdt_is_enabled(dw_wdt)) { 659 wdd->timeout = dw_wdt_get_timeout(dw_wdt); 660 set_bit(WDOG_HW_RUNNING, &wdd->status); 661 } else { 662 wdd->timeout = DW_WDT_DEFAULT_SECONDS; 663 watchdog_init_timeout(wdd, 0, dev); 664 } 665 666 platform_set_drvdata(pdev, dw_wdt); 667 668 watchdog_set_restart_priority(wdd, 128); 669 670 ret = watchdog_register_device(wdd); 671 if (ret) 672 goto out_disable_pclk; 673 674 dw_wdt_dbgfs_init(dw_wdt); 675 676 return 0; 677 678 out_disable_pclk: 679 clk_disable_unprepare(dw_wdt->pclk); 680 681 out_disable_clk: 682 clk_disable_unprepare(dw_wdt->clk); 683 return ret; 684 } 685 686 static int dw_wdt_drv_remove(struct platform_device *pdev) 687 { 688 struct dw_wdt *dw_wdt = platform_get_drvdata(pdev); 689 690 dw_wdt_dbgfs_clear(dw_wdt); 691 692 watchdog_unregister_device(&dw_wdt->wdd); 693 reset_control_assert(dw_wdt->rst); 694 clk_disable_unprepare(dw_wdt->pclk); 695 clk_disable_unprepare(dw_wdt->clk); 696 697 return 0; 698 } 699 700 #ifdef CONFIG_OF 701 static const struct of_device_id dw_wdt_of_match[] = { 702 { .compatible = "snps,dw-wdt", }, 703 { /* sentinel */ } 704 }; 705 MODULE_DEVICE_TABLE(of, dw_wdt_of_match); 706 #endif 707 708 static struct platform_driver dw_wdt_driver = { 709 .probe = dw_wdt_drv_probe, 710 .remove = dw_wdt_drv_remove, 711 .driver = { 712 .name = "dw_wdt", 713 .of_match_table = of_match_ptr(dw_wdt_of_match), 714 .pm = &dw_wdt_pm_ops, 715 }, 716 }; 717 718 module_platform_driver(dw_wdt_driver); 719 720 MODULE_AUTHOR("Jamie Iles"); 721 MODULE_DESCRIPTION("Synopsys DesignWare Watchdog Driver"); 722 MODULE_LICENSE("GPL"); 723