1 /* linux/drivers/char/watchdog/s3c2410_wdt.c 2 * 3 * Copyright (c) 2004 Simtec Electronics 4 * Ben Dooks <ben@simtec.co.uk> 5 * 6 * S3C2410 Watchdog Timer Support 7 * 8 * Based on, softdog.c by Alan Cox, 9 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk> 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License as published by 13 * the Free Software Foundation; either version 2 of the License, or 14 * (at your option) any later version. 15 * 16 * This program is distributed in the hope that it will be useful, 17 * but WITHOUT ANY WARRANTY; without even the implied warranty of 18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 19 * GNU General Public License for more details. 20 * 21 * You should have received a copy of the GNU General Public License 22 * along with this program; if not, write to the Free Software 23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 24 */ 25 26 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 27 28 #include <linux/module.h> 29 #include <linux/moduleparam.h> 30 #include <linux/types.h> 31 #include <linux/timer.h> 32 #include <linux/miscdevice.h> /* for MODULE_ALIAS_MISCDEV */ 33 #include <linux/watchdog.h> 34 #include <linux/init.h> 35 #include <linux/platform_device.h> 36 #include <linux/interrupt.h> 37 #include <linux/clk.h> 38 #include <linux/uaccess.h> 39 #include <linux/io.h> 40 #include <linux/cpufreq.h> 41 #include <linux/slab.h> 42 #include <linux/err.h> 43 #include <linux/of.h> 44 45 #include <mach/map.h> 46 47 #undef S3C_VA_WATCHDOG 48 #define S3C_VA_WATCHDOG (0) 49 50 #include <plat/regs-watchdog.h> 51 52 #define CONFIG_S3C2410_WATCHDOG_ATBOOT (0) 53 #define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME (15) 54 55 static bool nowayout = WATCHDOG_NOWAYOUT; 56 static int tmr_margin = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME; 57 static int tmr_atboot = CONFIG_S3C2410_WATCHDOG_ATBOOT; 58 static int soft_noboot; 59 static int debug; 60 61 module_param(tmr_margin, int, 0); 62 module_param(tmr_atboot, int, 0); 63 module_param(nowayout, bool, 0); 64 module_param(soft_noboot, int, 0); 65 module_param(debug, int, 0); 66 67 MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. (default=" 68 __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")"); 69 MODULE_PARM_DESC(tmr_atboot, 70 "Watchdog is started at boot time if set to 1, default=" 71 __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT)); 72 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 73 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 74 MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, " 75 "0 to reboot (default 0)"); 76 MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug (default 0)"); 77 78 static struct device *wdt_dev; /* platform device attached to */ 79 static struct resource *wdt_mem; 80 static struct resource *wdt_irq; 81 static struct clk *wdt_clock; 82 static void __iomem *wdt_base; 83 static unsigned int wdt_count; 84 static DEFINE_SPINLOCK(wdt_lock); 85 86 /* watchdog control routines */ 87 88 #define DBG(fmt, ...) \ 89 do { \ 90 if (debug) \ 91 pr_info(fmt, ##__VA_ARGS__); \ 92 } while (0) 93 94 /* functions */ 95 96 static int s3c2410wdt_keepalive(struct watchdog_device *wdd) 97 { 98 spin_lock(&wdt_lock); 99 writel(wdt_count, wdt_base + S3C2410_WTCNT); 100 spin_unlock(&wdt_lock); 101 102 return 0; 103 } 104 105 static void __s3c2410wdt_stop(void) 106 { 107 unsigned long wtcon; 108 109 wtcon = readl(wdt_base + S3C2410_WTCON); 110 wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN); 111 writel(wtcon, wdt_base + S3C2410_WTCON); 112 } 113 114 static int s3c2410wdt_stop(struct watchdog_device *wdd) 115 { 116 spin_lock(&wdt_lock); 117 __s3c2410wdt_stop(); 118 spin_unlock(&wdt_lock); 119 120 return 0; 121 } 122 123 static int s3c2410wdt_start(struct watchdog_device *wdd) 124 { 125 unsigned long wtcon; 126 127 spin_lock(&wdt_lock); 128 129 __s3c2410wdt_stop(); 130 131 wtcon = readl(wdt_base + S3C2410_WTCON); 132 wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128; 133 134 if (soft_noboot) { 135 wtcon |= S3C2410_WTCON_INTEN; 136 wtcon &= ~S3C2410_WTCON_RSTEN; 137 } else { 138 wtcon &= ~S3C2410_WTCON_INTEN; 139 wtcon |= S3C2410_WTCON_RSTEN; 140 } 141 142 DBG("%s: wdt_count=0x%08x, wtcon=%08lx\n", 143 __func__, wdt_count, wtcon); 144 145 writel(wdt_count, wdt_base + S3C2410_WTDAT); 146 writel(wdt_count, wdt_base + S3C2410_WTCNT); 147 writel(wtcon, wdt_base + S3C2410_WTCON); 148 spin_unlock(&wdt_lock); 149 150 return 0; 151 } 152 153 static inline int s3c2410wdt_is_running(void) 154 { 155 return readl(wdt_base + S3C2410_WTCON) & S3C2410_WTCON_ENABLE; 156 } 157 158 static int s3c2410wdt_set_heartbeat(struct watchdog_device *wdd, unsigned timeout) 159 { 160 unsigned long freq = clk_get_rate(wdt_clock); 161 unsigned int count; 162 unsigned int divisor = 1; 163 unsigned long wtcon; 164 165 if (timeout < 1) 166 return -EINVAL; 167 168 freq /= 128; 169 count = timeout * freq; 170 171 DBG("%s: count=%d, timeout=%d, freq=%lu\n", 172 __func__, count, timeout, freq); 173 174 /* if the count is bigger than the watchdog register, 175 then work out what we need to do (and if) we can 176 actually make this value 177 */ 178 179 if (count >= 0x10000) { 180 for (divisor = 1; divisor <= 0x100; divisor++) { 181 if ((count / divisor) < 0x10000) 182 break; 183 } 184 185 if ((count / divisor) >= 0x10000) { 186 dev_err(wdt_dev, "timeout %d too big\n", timeout); 187 return -EINVAL; 188 } 189 } 190 191 DBG("%s: timeout=%d, divisor=%d, count=%d (%08x)\n", 192 __func__, timeout, divisor, count, count/divisor); 193 194 count /= divisor; 195 wdt_count = count; 196 197 /* update the pre-scaler */ 198 wtcon = readl(wdt_base + S3C2410_WTCON); 199 wtcon &= ~S3C2410_WTCON_PRESCALE_MASK; 200 wtcon |= S3C2410_WTCON_PRESCALE(divisor-1); 201 202 writel(count, wdt_base + S3C2410_WTDAT); 203 writel(wtcon, wdt_base + S3C2410_WTCON); 204 205 wdd->timeout = (count * divisor) / freq; 206 207 return 0; 208 } 209 210 #define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE) 211 212 static const struct watchdog_info s3c2410_wdt_ident = { 213 .options = OPTIONS, 214 .firmware_version = 0, 215 .identity = "S3C2410 Watchdog", 216 }; 217 218 static struct watchdog_ops s3c2410wdt_ops = { 219 .owner = THIS_MODULE, 220 .start = s3c2410wdt_start, 221 .stop = s3c2410wdt_stop, 222 .ping = s3c2410wdt_keepalive, 223 .set_timeout = s3c2410wdt_set_heartbeat, 224 }; 225 226 static struct watchdog_device s3c2410_wdd = { 227 .info = &s3c2410_wdt_ident, 228 .ops = &s3c2410wdt_ops, 229 }; 230 231 /* interrupt handler code */ 232 233 static irqreturn_t s3c2410wdt_irq(int irqno, void *param) 234 { 235 dev_info(wdt_dev, "watchdog timer expired (irq)\n"); 236 237 s3c2410wdt_keepalive(&s3c2410_wdd); 238 return IRQ_HANDLED; 239 } 240 241 242 #ifdef CONFIG_CPU_FREQ 243 244 static int s3c2410wdt_cpufreq_transition(struct notifier_block *nb, 245 unsigned long val, void *data) 246 { 247 int ret; 248 249 if (!s3c2410wdt_is_running()) 250 goto done; 251 252 if (val == CPUFREQ_PRECHANGE) { 253 /* To ensure that over the change we don't cause the 254 * watchdog to trigger, we perform an keep-alive if 255 * the watchdog is running. 256 */ 257 258 s3c2410wdt_keepalive(&s3c2410_wdd); 259 } else if (val == CPUFREQ_POSTCHANGE) { 260 s3c2410wdt_stop(&s3c2410_wdd); 261 262 ret = s3c2410wdt_set_heartbeat(&s3c2410_wdd, s3c2410_wdd.timeout); 263 264 if (ret >= 0) 265 s3c2410wdt_start(&s3c2410_wdd); 266 else 267 goto err; 268 } 269 270 done: 271 return 0; 272 273 err: 274 dev_err(wdt_dev, "cannot set new value for timeout %d\n", 275 s3c2410_wdd.timeout); 276 return ret; 277 } 278 279 static struct notifier_block s3c2410wdt_cpufreq_transition_nb = { 280 .notifier_call = s3c2410wdt_cpufreq_transition, 281 }; 282 283 static inline int s3c2410wdt_cpufreq_register(void) 284 { 285 return cpufreq_register_notifier(&s3c2410wdt_cpufreq_transition_nb, 286 CPUFREQ_TRANSITION_NOTIFIER); 287 } 288 289 static inline void s3c2410wdt_cpufreq_deregister(void) 290 { 291 cpufreq_unregister_notifier(&s3c2410wdt_cpufreq_transition_nb, 292 CPUFREQ_TRANSITION_NOTIFIER); 293 } 294 295 #else 296 static inline int s3c2410wdt_cpufreq_register(void) 297 { 298 return 0; 299 } 300 301 static inline void s3c2410wdt_cpufreq_deregister(void) 302 { 303 } 304 #endif 305 306 static int __devinit s3c2410wdt_probe(struct platform_device *pdev) 307 { 308 struct device *dev; 309 unsigned int wtcon; 310 int started = 0; 311 int ret; 312 int size; 313 314 DBG("%s: probe=%p\n", __func__, pdev); 315 316 dev = &pdev->dev; 317 wdt_dev = &pdev->dev; 318 319 wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); 320 if (wdt_mem == NULL) { 321 dev_err(dev, "no memory resource specified\n"); 322 return -ENOENT; 323 } 324 325 wdt_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 326 if (wdt_irq == NULL) { 327 dev_err(dev, "no irq resource specified\n"); 328 ret = -ENOENT; 329 goto err; 330 } 331 332 /* get the memory region for the watchdog timer */ 333 334 size = resource_size(wdt_mem); 335 if (!request_mem_region(wdt_mem->start, size, pdev->name)) { 336 dev_err(dev, "failed to get memory region\n"); 337 ret = -EBUSY; 338 goto err; 339 } 340 341 wdt_base = ioremap(wdt_mem->start, size); 342 if (wdt_base == NULL) { 343 dev_err(dev, "failed to ioremap() region\n"); 344 ret = -EINVAL; 345 goto err_req; 346 } 347 348 DBG("probe: mapped wdt_base=%p\n", wdt_base); 349 350 wdt_clock = clk_get(&pdev->dev, "watchdog"); 351 if (IS_ERR(wdt_clock)) { 352 dev_err(dev, "failed to find watchdog clock source\n"); 353 ret = PTR_ERR(wdt_clock); 354 goto err_map; 355 } 356 357 clk_enable(wdt_clock); 358 359 ret = s3c2410wdt_cpufreq_register(); 360 if (ret < 0) { 361 pr_err("failed to register cpufreq\n"); 362 goto err_clk; 363 } 364 365 /* see if we can actually set the requested timer margin, and if 366 * not, try the default value */ 367 368 if (s3c2410wdt_set_heartbeat(&s3c2410_wdd, tmr_margin)) { 369 started = s3c2410wdt_set_heartbeat(&s3c2410_wdd, 370 CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME); 371 372 if (started == 0) 373 dev_info(dev, 374 "tmr_margin value out of range, default %d used\n", 375 CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME); 376 else 377 dev_info(dev, "default timer value is out of range, " 378 "cannot start\n"); 379 } 380 381 ret = request_irq(wdt_irq->start, s3c2410wdt_irq, 0, pdev->name, pdev); 382 if (ret != 0) { 383 dev_err(dev, "failed to install irq (%d)\n", ret); 384 goto err_cpufreq; 385 } 386 387 watchdog_set_nowayout(&s3c2410_wdd, nowayout); 388 389 ret = watchdog_register_device(&s3c2410_wdd); 390 if (ret) { 391 dev_err(dev, "cannot register watchdog (%d)\n", ret); 392 goto err_irq; 393 } 394 395 if (tmr_atboot && started == 0) { 396 dev_info(dev, "starting watchdog timer\n"); 397 s3c2410wdt_start(&s3c2410_wdd); 398 } else if (!tmr_atboot) { 399 /* if we're not enabling the watchdog, then ensure it is 400 * disabled if it has been left running from the bootloader 401 * or other source */ 402 403 s3c2410wdt_stop(&s3c2410_wdd); 404 } 405 406 /* print out a statement of readiness */ 407 408 wtcon = readl(wdt_base + S3C2410_WTCON); 409 410 dev_info(dev, "watchdog %sactive, reset %sabled, irq %sabled\n", 411 (wtcon & S3C2410_WTCON_ENABLE) ? "" : "in", 412 (wtcon & S3C2410_WTCON_RSTEN) ? "en" : "dis", 413 (wtcon & S3C2410_WTCON_INTEN) ? "en" : "dis"); 414 415 return 0; 416 417 err_irq: 418 free_irq(wdt_irq->start, pdev); 419 420 err_cpufreq: 421 s3c2410wdt_cpufreq_deregister(); 422 423 err_clk: 424 clk_disable(wdt_clock); 425 clk_put(wdt_clock); 426 wdt_clock = NULL; 427 428 err_map: 429 iounmap(wdt_base); 430 431 err_req: 432 release_mem_region(wdt_mem->start, size); 433 434 err: 435 wdt_irq = NULL; 436 wdt_mem = NULL; 437 return ret; 438 } 439 440 static int __devexit s3c2410wdt_remove(struct platform_device *dev) 441 { 442 watchdog_unregister_device(&s3c2410_wdd); 443 444 free_irq(wdt_irq->start, dev); 445 446 s3c2410wdt_cpufreq_deregister(); 447 448 clk_disable(wdt_clock); 449 clk_put(wdt_clock); 450 wdt_clock = NULL; 451 452 iounmap(wdt_base); 453 454 release_mem_region(wdt_mem->start, resource_size(wdt_mem)); 455 wdt_irq = NULL; 456 wdt_mem = NULL; 457 return 0; 458 } 459 460 static void s3c2410wdt_shutdown(struct platform_device *dev) 461 { 462 s3c2410wdt_stop(&s3c2410_wdd); 463 } 464 465 #ifdef CONFIG_PM 466 467 static unsigned long wtcon_save; 468 static unsigned long wtdat_save; 469 470 static int s3c2410wdt_suspend(struct platform_device *dev, pm_message_t state) 471 { 472 /* Save watchdog state, and turn it off. */ 473 wtcon_save = readl(wdt_base + S3C2410_WTCON); 474 wtdat_save = readl(wdt_base + S3C2410_WTDAT); 475 476 /* Note that WTCNT doesn't need to be saved. */ 477 s3c2410wdt_stop(&s3c2410_wdd); 478 479 return 0; 480 } 481 482 static int s3c2410wdt_resume(struct platform_device *dev) 483 { 484 /* Restore watchdog state. */ 485 486 writel(wtdat_save, wdt_base + S3C2410_WTDAT); 487 writel(wtdat_save, wdt_base + S3C2410_WTCNT); /* Reset count */ 488 writel(wtcon_save, wdt_base + S3C2410_WTCON); 489 490 pr_info("watchdog %sabled\n", 491 (wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis"); 492 493 return 0; 494 } 495 496 #else 497 #define s3c2410wdt_suspend NULL 498 #define s3c2410wdt_resume NULL 499 #endif /* CONFIG_PM */ 500 501 #ifdef CONFIG_OF 502 static const struct of_device_id s3c2410_wdt_match[] = { 503 { .compatible = "samsung,s3c2410-wdt" }, 504 {}, 505 }; 506 MODULE_DEVICE_TABLE(of, s3c2410_wdt_match); 507 #endif 508 509 static struct platform_driver s3c2410wdt_driver = { 510 .probe = s3c2410wdt_probe, 511 .remove = __devexit_p(s3c2410wdt_remove), 512 .shutdown = s3c2410wdt_shutdown, 513 .suspend = s3c2410wdt_suspend, 514 .resume = s3c2410wdt_resume, 515 .driver = { 516 .owner = THIS_MODULE, 517 .name = "s3c2410-wdt", 518 .of_match_table = of_match_ptr(s3c2410_wdt_match), 519 }, 520 }; 521 522 module_platform_driver(s3c2410wdt_driver); 523 524 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, " 525 "Dimitry Andric <dimitry.andric@tomtom.com>"); 526 MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver"); 527 MODULE_LICENSE("GPL"); 528 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 529 MODULE_ALIAS("platform:s3c2410-wdt"); 530