1 /* 2 * omap_wdt.c 3 * 4 * Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog 5 * 6 * Author: MontaVista Software, Inc. 7 * <gdavis@mvista.com> or <source@mvista.com> 8 * 9 * 2003 (c) MontaVista Software, Inc. This file is licensed under the 10 * terms of the GNU General Public License version 2. This program is 11 * licensed "as is" without any warranty of any kind, whether express 12 * or implied. 13 * 14 * History: 15 * 16 * 20030527: George G. Davis <gdavis@mvista.com> 17 * Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c 18 * (c) Copyright 2000 Oleg Drokin <green@crimea.edu> 19 * Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk> 20 * 21 * Copyright (c) 2004 Texas Instruments. 22 * 1. Modified to support OMAP1610 32-KHz watchdog timer 23 * 2. Ported to 2.6 kernel 24 * 25 * Copyright (c) 2005 David Brownell 26 * Use the driver model and standard identifiers; handle bigger timeouts. 27 */ 28 29 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 30 31 #include <linux/module.h> 32 #include <linux/types.h> 33 #include <linux/kernel.h> 34 #include <linux/mm.h> 35 #include <linux/watchdog.h> 36 #include <linux/reboot.h> 37 #include <linux/err.h> 38 #include <linux/platform_device.h> 39 #include <linux/moduleparam.h> 40 #include <linux/io.h> 41 #include <linux/slab.h> 42 #include <linux/pm_runtime.h> 43 #include <linux/platform_data/omap-wd-timer.h> 44 45 #include "omap_wdt.h" 46 47 static bool nowayout = WATCHDOG_NOWAYOUT; 48 module_param(nowayout, bool, 0); 49 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " 50 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 51 52 static unsigned timer_margin; 53 module_param(timer_margin, uint, 0); 54 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)"); 55 56 #define to_omap_wdt_dev(_wdog) container_of(_wdog, struct omap_wdt_dev, wdog) 57 58 static bool early_enable; 59 module_param(early_enable, bool, 0); 60 MODULE_PARM_DESC(early_enable, 61 "Watchdog is started on module insertion (default=0)"); 62 63 struct omap_wdt_dev { 64 struct watchdog_device wdog; 65 void __iomem *base; /* physical */ 66 struct device *dev; 67 bool omap_wdt_users; 68 int wdt_trgr_pattern; 69 struct mutex lock; /* to avoid races with PM */ 70 }; 71 72 static void omap_wdt_reload(struct omap_wdt_dev *wdev) 73 { 74 void __iomem *base = wdev->base; 75 76 /* wait for posted write to complete */ 77 while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x08) 78 cpu_relax(); 79 80 wdev->wdt_trgr_pattern = ~wdev->wdt_trgr_pattern; 81 writel_relaxed(wdev->wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR)); 82 83 /* wait for posted write to complete */ 84 while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x08) 85 cpu_relax(); 86 /* reloaded WCRR from WLDR */ 87 } 88 89 static void omap_wdt_enable(struct omap_wdt_dev *wdev) 90 { 91 void __iomem *base = wdev->base; 92 93 /* Sequence to enable the watchdog */ 94 writel_relaxed(0xBBBB, base + OMAP_WATCHDOG_SPR); 95 while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x10) 96 cpu_relax(); 97 98 writel_relaxed(0x4444, base + OMAP_WATCHDOG_SPR); 99 while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x10) 100 cpu_relax(); 101 } 102 103 static void omap_wdt_disable(struct omap_wdt_dev *wdev) 104 { 105 void __iomem *base = wdev->base; 106 107 /* sequence required to disable watchdog */ 108 writel_relaxed(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */ 109 while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x10) 110 cpu_relax(); 111 112 writel_relaxed(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */ 113 while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x10) 114 cpu_relax(); 115 } 116 117 static void omap_wdt_set_timer(struct omap_wdt_dev *wdev, 118 unsigned int timeout) 119 { 120 u32 pre_margin = GET_WLDR_VAL(timeout); 121 void __iomem *base = wdev->base; 122 123 /* just count up at 32 KHz */ 124 while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x04) 125 cpu_relax(); 126 127 writel_relaxed(pre_margin, base + OMAP_WATCHDOG_LDR); 128 while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x04) 129 cpu_relax(); 130 } 131 132 static int omap_wdt_start(struct watchdog_device *wdog) 133 { 134 struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog); 135 void __iomem *base = wdev->base; 136 137 mutex_lock(&wdev->lock); 138 139 wdev->omap_wdt_users = true; 140 141 pm_runtime_get_sync(wdev->dev); 142 143 /* 144 * Make sure the watchdog is disabled. This is unfortunately required 145 * because writing to various registers with the watchdog running has no 146 * effect. 147 */ 148 omap_wdt_disable(wdev); 149 150 /* initialize prescaler */ 151 while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x01) 152 cpu_relax(); 153 154 writel_relaxed((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL); 155 while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x01) 156 cpu_relax(); 157 158 omap_wdt_set_timer(wdev, wdog->timeout); 159 omap_wdt_reload(wdev); /* trigger loading of new timeout value */ 160 omap_wdt_enable(wdev); 161 162 mutex_unlock(&wdev->lock); 163 164 return 0; 165 } 166 167 static int omap_wdt_stop(struct watchdog_device *wdog) 168 { 169 struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog); 170 171 mutex_lock(&wdev->lock); 172 omap_wdt_disable(wdev); 173 pm_runtime_put_sync(wdev->dev); 174 wdev->omap_wdt_users = false; 175 mutex_unlock(&wdev->lock); 176 return 0; 177 } 178 179 static int omap_wdt_ping(struct watchdog_device *wdog) 180 { 181 struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog); 182 183 mutex_lock(&wdev->lock); 184 omap_wdt_reload(wdev); 185 mutex_unlock(&wdev->lock); 186 187 return 0; 188 } 189 190 static int omap_wdt_set_timeout(struct watchdog_device *wdog, 191 unsigned int timeout) 192 { 193 struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog); 194 195 mutex_lock(&wdev->lock); 196 omap_wdt_disable(wdev); 197 omap_wdt_set_timer(wdev, timeout); 198 omap_wdt_enable(wdev); 199 omap_wdt_reload(wdev); 200 wdog->timeout = timeout; 201 mutex_unlock(&wdev->lock); 202 203 return 0; 204 } 205 206 static unsigned int omap_wdt_get_timeleft(struct watchdog_device *wdog) 207 { 208 struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog); 209 void __iomem *base = wdev->base; 210 u32 value; 211 212 value = readl_relaxed(base + OMAP_WATCHDOG_CRR); 213 return GET_WCCR_SECS(value); 214 } 215 216 static const struct watchdog_info omap_wdt_info = { 217 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, 218 .identity = "OMAP Watchdog", 219 }; 220 221 static const struct watchdog_ops omap_wdt_ops = { 222 .owner = THIS_MODULE, 223 .start = omap_wdt_start, 224 .stop = omap_wdt_stop, 225 .ping = omap_wdt_ping, 226 .set_timeout = omap_wdt_set_timeout, 227 .get_timeleft = omap_wdt_get_timeleft, 228 }; 229 230 static int omap_wdt_probe(struct platform_device *pdev) 231 { 232 struct omap_wd_timer_platform_data *pdata = dev_get_platdata(&pdev->dev); 233 struct resource *res; 234 struct omap_wdt_dev *wdev; 235 int ret; 236 237 wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL); 238 if (!wdev) 239 return -ENOMEM; 240 241 wdev->omap_wdt_users = false; 242 wdev->dev = &pdev->dev; 243 wdev->wdt_trgr_pattern = 0x1234; 244 mutex_init(&wdev->lock); 245 246 /* reserve static register mappings */ 247 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 248 wdev->base = devm_ioremap_resource(&pdev->dev, res); 249 if (IS_ERR(wdev->base)) 250 return PTR_ERR(wdev->base); 251 252 wdev->wdog.info = &omap_wdt_info; 253 wdev->wdog.ops = &omap_wdt_ops; 254 wdev->wdog.min_timeout = TIMER_MARGIN_MIN; 255 wdev->wdog.max_timeout = TIMER_MARGIN_MAX; 256 wdev->wdog.parent = &pdev->dev; 257 258 if (watchdog_init_timeout(&wdev->wdog, timer_margin, &pdev->dev) < 0) 259 wdev->wdog.timeout = TIMER_MARGIN_DEFAULT; 260 261 watchdog_set_nowayout(&wdev->wdog, nowayout); 262 263 platform_set_drvdata(pdev, wdev); 264 265 pm_runtime_enable(wdev->dev); 266 pm_runtime_get_sync(wdev->dev); 267 268 if (pdata && pdata->read_reset_sources) { 269 u32 rs = pdata->read_reset_sources(); 270 if (rs & (1 << OMAP_MPU_WD_RST_SRC_ID_SHIFT)) 271 wdev->wdog.bootstatus = WDIOF_CARDRESET; 272 } 273 274 omap_wdt_disable(wdev); 275 276 ret = watchdog_register_device(&wdev->wdog); 277 if (ret) { 278 pm_runtime_disable(wdev->dev); 279 return ret; 280 } 281 282 pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n", 283 readl_relaxed(wdev->base + OMAP_WATCHDOG_REV) & 0xFF, 284 wdev->wdog.timeout); 285 286 pm_runtime_put_sync(wdev->dev); 287 288 if (early_enable) 289 omap_wdt_start(&wdev->wdog); 290 291 return 0; 292 } 293 294 static void omap_wdt_shutdown(struct platform_device *pdev) 295 { 296 struct omap_wdt_dev *wdev = platform_get_drvdata(pdev); 297 298 mutex_lock(&wdev->lock); 299 if (wdev->omap_wdt_users) { 300 omap_wdt_disable(wdev); 301 pm_runtime_put_sync(wdev->dev); 302 } 303 mutex_unlock(&wdev->lock); 304 } 305 306 static int omap_wdt_remove(struct platform_device *pdev) 307 { 308 struct omap_wdt_dev *wdev = platform_get_drvdata(pdev); 309 310 pm_runtime_disable(wdev->dev); 311 watchdog_unregister_device(&wdev->wdog); 312 313 return 0; 314 } 315 316 #ifdef CONFIG_PM 317 318 /* REVISIT ... not clear this is the best way to handle system suspend; and 319 * it's very inappropriate for selective device suspend (e.g. suspending this 320 * through sysfs rather than by stopping the watchdog daemon). Also, this 321 * may not play well enough with NOWAYOUT... 322 */ 323 324 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state) 325 { 326 struct omap_wdt_dev *wdev = platform_get_drvdata(pdev); 327 328 mutex_lock(&wdev->lock); 329 if (wdev->omap_wdt_users) { 330 omap_wdt_disable(wdev); 331 pm_runtime_put_sync(wdev->dev); 332 } 333 mutex_unlock(&wdev->lock); 334 335 return 0; 336 } 337 338 static int omap_wdt_resume(struct platform_device *pdev) 339 { 340 struct omap_wdt_dev *wdev = platform_get_drvdata(pdev); 341 342 mutex_lock(&wdev->lock); 343 if (wdev->omap_wdt_users) { 344 pm_runtime_get_sync(wdev->dev); 345 omap_wdt_enable(wdev); 346 omap_wdt_reload(wdev); 347 } 348 mutex_unlock(&wdev->lock); 349 350 return 0; 351 } 352 353 #else 354 #define omap_wdt_suspend NULL 355 #define omap_wdt_resume NULL 356 #endif 357 358 static const struct of_device_id omap_wdt_of_match[] = { 359 { .compatible = "ti,omap3-wdt", }, 360 {}, 361 }; 362 MODULE_DEVICE_TABLE(of, omap_wdt_of_match); 363 364 static struct platform_driver omap_wdt_driver = { 365 .probe = omap_wdt_probe, 366 .remove = omap_wdt_remove, 367 .shutdown = omap_wdt_shutdown, 368 .suspend = omap_wdt_suspend, 369 .resume = omap_wdt_resume, 370 .driver = { 371 .name = "omap_wdt", 372 .of_match_table = omap_wdt_of_match, 373 }, 374 }; 375 376 module_platform_driver(omap_wdt_driver); 377 378 MODULE_AUTHOR("George G. Davis"); 379 MODULE_LICENSE("GPL"); 380 MODULE_ALIAS("platform:omap_wdt"); 381