1 /* 2 * Watchdog driver for IMX2 and later processors 3 * 4 * Copyright (C) 2010 Wolfram Sang, Pengutronix e.K. <w.sang@pengutronix.de> 5 * Copyright (C) 2014 Freescale Semiconductor, Inc. 6 * 7 * some parts adapted by similar drivers from Darius Augulis and Vladimir 8 * Zapolskiy, additional improvements by Wim Van Sebroeck. 9 * 10 * This program is free software; you can redistribute it and/or modify it 11 * under the terms of the GNU General Public License version 2 as published by 12 * the Free Software Foundation. 13 * 14 * NOTE: MX1 has a slightly different Watchdog than MX2 and later: 15 * 16 * MX1: MX2+: 17 * ---- ----- 18 * Registers: 32-bit 16-bit 19 * Stopable timer: Yes No 20 * Need to enable clk: No Yes 21 * Halt on suspend: Manual Can be automatic 22 */ 23 24 #include <linux/clk.h> 25 #include <linux/delay.h> 26 #include <linux/init.h> 27 #include <linux/interrupt.h> 28 #include <linux/io.h> 29 #include <linux/kernel.h> 30 #include <linux/module.h> 31 #include <linux/moduleparam.h> 32 #include <linux/of_address.h> 33 #include <linux/platform_device.h> 34 #include <linux/regmap.h> 35 #include <linux/watchdog.h> 36 37 #define DRIVER_NAME "imx2-wdt" 38 39 #define IMX2_WDT_WCR 0x00 /* Control Register */ 40 #define IMX2_WDT_WCR_WT (0xFF << 8) /* -> Watchdog Timeout Field */ 41 #define IMX2_WDT_WCR_WDA BIT(5) /* -> External Reset WDOG_B */ 42 #define IMX2_WDT_WCR_SRS BIT(4) /* -> Software Reset Signal */ 43 #define IMX2_WDT_WCR_WRE BIT(3) /* -> WDOG Reset Enable */ 44 #define IMX2_WDT_WCR_WDE BIT(2) /* -> Watchdog Enable */ 45 #define IMX2_WDT_WCR_WDZST BIT(0) /* -> Watchdog timer Suspend */ 46 47 #define IMX2_WDT_WSR 0x02 /* Service Register */ 48 #define IMX2_WDT_SEQ1 0x5555 /* -> service sequence 1 */ 49 #define IMX2_WDT_SEQ2 0xAAAA /* -> service sequence 2 */ 50 51 #define IMX2_WDT_WRSR 0x04 /* Reset Status Register */ 52 #define IMX2_WDT_WRSR_TOUT BIT(1) /* -> Reset due to Timeout */ 53 54 #define IMX2_WDT_WICR 0x06 /* Interrupt Control Register */ 55 #define IMX2_WDT_WICR_WIE BIT(15) /* -> Interrupt Enable */ 56 #define IMX2_WDT_WICR_WTIS BIT(14) /* -> Interrupt Status */ 57 #define IMX2_WDT_WICR_WICT 0xFF /* -> Interrupt Count Timeout */ 58 59 #define IMX2_WDT_WMCR 0x08 /* Misc Register */ 60 61 #define IMX2_WDT_MAX_TIME 128 62 #define IMX2_WDT_DEFAULT_TIME 60 /* in seconds */ 63 64 #define WDOG_SEC_TO_COUNT(s) ((s * 2 - 1) << 8) 65 66 struct imx2_wdt_device { 67 struct clk *clk; 68 struct regmap *regmap; 69 struct watchdog_device wdog; 70 bool ext_reset; 71 }; 72 73 static bool nowayout = WATCHDOG_NOWAYOUT; 74 module_param(nowayout, bool, 0); 75 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 76 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 77 78 79 static unsigned timeout; 80 module_param(timeout, uint, 0); 81 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" 82 __MODULE_STRING(IMX2_WDT_DEFAULT_TIME) ")"); 83 84 static const struct watchdog_info imx2_wdt_info = { 85 .identity = "imx2+ watchdog", 86 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, 87 }; 88 89 static const struct watchdog_info imx2_wdt_pretimeout_info = { 90 .identity = "imx2+ watchdog", 91 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | 92 WDIOF_PRETIMEOUT, 93 }; 94 95 static int imx2_wdt_restart(struct watchdog_device *wdog, unsigned long action, 96 void *data) 97 { 98 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 99 unsigned int wcr_enable = IMX2_WDT_WCR_WDE; 100 101 /* Use internal reset or external - not both */ 102 if (wdev->ext_reset) 103 wcr_enable |= IMX2_WDT_WCR_SRS; /* do not assert int reset */ 104 else 105 wcr_enable |= IMX2_WDT_WCR_WDA; /* do not assert ext-reset */ 106 107 /* Assert SRS signal */ 108 regmap_write(wdev->regmap, IMX2_WDT_WCR, wcr_enable); 109 /* 110 * Due to imx6q errata ERR004346 (WDOG: WDOG SRS bit requires to be 111 * written twice), we add another two writes to ensure there must be at 112 * least two writes happen in the same one 32kHz clock period. We save 113 * the target check here, since the writes shouldn't be a huge burden 114 * for other platforms. 115 */ 116 regmap_write(wdev->regmap, IMX2_WDT_WCR, wcr_enable); 117 regmap_write(wdev->regmap, IMX2_WDT_WCR, wcr_enable); 118 119 /* wait for reset to assert... */ 120 mdelay(500); 121 122 return 0; 123 } 124 125 static inline void imx2_wdt_setup(struct watchdog_device *wdog) 126 { 127 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 128 u32 val; 129 130 regmap_read(wdev->regmap, IMX2_WDT_WCR, &val); 131 132 /* Suspend timer in low power mode, write once-only */ 133 val |= IMX2_WDT_WCR_WDZST; 134 /* Strip the old watchdog Time-Out value */ 135 val &= ~IMX2_WDT_WCR_WT; 136 /* Generate internal chip-level reset if WDOG times out */ 137 if (!wdev->ext_reset) 138 val &= ~IMX2_WDT_WCR_WRE; 139 /* Or if external-reset assert WDOG_B reset only on time-out */ 140 else 141 val |= IMX2_WDT_WCR_WRE; 142 /* Keep Watchdog Disabled */ 143 val &= ~IMX2_WDT_WCR_WDE; 144 /* Set the watchdog's Time-Out value */ 145 val |= WDOG_SEC_TO_COUNT(wdog->timeout); 146 147 regmap_write(wdev->regmap, IMX2_WDT_WCR, val); 148 149 /* enable the watchdog */ 150 val |= IMX2_WDT_WCR_WDE; 151 regmap_write(wdev->regmap, IMX2_WDT_WCR, val); 152 } 153 154 static inline bool imx2_wdt_is_running(struct imx2_wdt_device *wdev) 155 { 156 u32 val; 157 158 regmap_read(wdev->regmap, IMX2_WDT_WCR, &val); 159 160 return val & IMX2_WDT_WCR_WDE; 161 } 162 163 static int imx2_wdt_ping(struct watchdog_device *wdog) 164 { 165 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 166 167 regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ1); 168 regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ2); 169 return 0; 170 } 171 172 static void __imx2_wdt_set_timeout(struct watchdog_device *wdog, 173 unsigned int new_timeout) 174 { 175 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 176 177 regmap_update_bits(wdev->regmap, IMX2_WDT_WCR, IMX2_WDT_WCR_WT, 178 WDOG_SEC_TO_COUNT(new_timeout)); 179 } 180 181 static int imx2_wdt_set_timeout(struct watchdog_device *wdog, 182 unsigned int new_timeout) 183 { 184 __imx2_wdt_set_timeout(wdog, new_timeout); 185 186 wdog->timeout = new_timeout; 187 return 0; 188 } 189 190 static int imx2_wdt_set_pretimeout(struct watchdog_device *wdog, 191 unsigned int new_pretimeout) 192 { 193 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 194 195 if (new_pretimeout >= IMX2_WDT_MAX_TIME) 196 return -EINVAL; 197 198 wdog->pretimeout = new_pretimeout; 199 200 regmap_update_bits(wdev->regmap, IMX2_WDT_WICR, 201 IMX2_WDT_WICR_WIE | IMX2_WDT_WICR_WICT, 202 IMX2_WDT_WICR_WIE | (new_pretimeout << 1)); 203 return 0; 204 } 205 206 static irqreturn_t imx2_wdt_isr(int irq, void *wdog_arg) 207 { 208 struct watchdog_device *wdog = wdog_arg; 209 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 210 211 regmap_write_bits(wdev->regmap, IMX2_WDT_WICR, 212 IMX2_WDT_WICR_WTIS, IMX2_WDT_WICR_WTIS); 213 214 watchdog_notify_pretimeout(wdog); 215 216 return IRQ_HANDLED; 217 } 218 219 static int imx2_wdt_start(struct watchdog_device *wdog) 220 { 221 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 222 223 if (imx2_wdt_is_running(wdev)) 224 imx2_wdt_set_timeout(wdog, wdog->timeout); 225 else 226 imx2_wdt_setup(wdog); 227 228 set_bit(WDOG_HW_RUNNING, &wdog->status); 229 230 return imx2_wdt_ping(wdog); 231 } 232 233 static const struct watchdog_ops imx2_wdt_ops = { 234 .owner = THIS_MODULE, 235 .start = imx2_wdt_start, 236 .ping = imx2_wdt_ping, 237 .set_timeout = imx2_wdt_set_timeout, 238 .set_pretimeout = imx2_wdt_set_pretimeout, 239 .restart = imx2_wdt_restart, 240 }; 241 242 static const struct regmap_config imx2_wdt_regmap_config = { 243 .reg_bits = 16, 244 .reg_stride = 2, 245 .val_bits = 16, 246 .max_register = 0x8, 247 }; 248 249 static int __init imx2_wdt_probe(struct platform_device *pdev) 250 { 251 struct imx2_wdt_device *wdev; 252 struct watchdog_device *wdog; 253 struct resource *res; 254 void __iomem *base; 255 int ret; 256 u32 val; 257 258 wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL); 259 if (!wdev) 260 return -ENOMEM; 261 262 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 263 base = devm_ioremap_resource(&pdev->dev, res); 264 if (IS_ERR(base)) 265 return PTR_ERR(base); 266 267 wdev->regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base, 268 &imx2_wdt_regmap_config); 269 if (IS_ERR(wdev->regmap)) { 270 dev_err(&pdev->dev, "regmap init failed\n"); 271 return PTR_ERR(wdev->regmap); 272 } 273 274 wdev->clk = devm_clk_get(&pdev->dev, NULL); 275 if (IS_ERR(wdev->clk)) { 276 dev_err(&pdev->dev, "can't get Watchdog clock\n"); 277 return PTR_ERR(wdev->clk); 278 } 279 280 wdog = &wdev->wdog; 281 wdog->info = &imx2_wdt_info; 282 wdog->ops = &imx2_wdt_ops; 283 wdog->min_timeout = 1; 284 wdog->timeout = IMX2_WDT_DEFAULT_TIME; 285 wdog->max_hw_heartbeat_ms = IMX2_WDT_MAX_TIME * 1000; 286 wdog->parent = &pdev->dev; 287 288 ret = platform_get_irq(pdev, 0); 289 if (ret > 0) 290 if (!devm_request_irq(&pdev->dev, ret, imx2_wdt_isr, 0, 291 dev_name(&pdev->dev), wdog)) 292 wdog->info = &imx2_wdt_pretimeout_info; 293 294 ret = clk_prepare_enable(wdev->clk); 295 if (ret) 296 return ret; 297 298 regmap_read(wdev->regmap, IMX2_WDT_WRSR, &val); 299 wdog->bootstatus = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0; 300 301 wdev->ext_reset = of_property_read_bool(pdev->dev.of_node, 302 "fsl,ext-reset-output"); 303 platform_set_drvdata(pdev, wdog); 304 watchdog_set_drvdata(wdog, wdev); 305 watchdog_set_nowayout(wdog, nowayout); 306 watchdog_set_restart_priority(wdog, 128); 307 watchdog_init_timeout(wdog, timeout, &pdev->dev); 308 309 if (imx2_wdt_is_running(wdev)) { 310 imx2_wdt_set_timeout(wdog, wdog->timeout); 311 set_bit(WDOG_HW_RUNNING, &wdog->status); 312 } 313 314 /* 315 * Disable the watchdog power down counter at boot. Otherwise the power 316 * down counter will pull down the #WDOG interrupt line for one clock 317 * cycle. 318 */ 319 regmap_write(wdev->regmap, IMX2_WDT_WMCR, 0); 320 321 ret = watchdog_register_device(wdog); 322 if (ret) { 323 dev_err(&pdev->dev, "cannot register watchdog device\n"); 324 goto disable_clk; 325 } 326 327 dev_info(&pdev->dev, "timeout %d sec (nowayout=%d)\n", 328 wdog->timeout, nowayout); 329 330 return 0; 331 332 disable_clk: 333 clk_disable_unprepare(wdev->clk); 334 return ret; 335 } 336 337 static int __exit imx2_wdt_remove(struct platform_device *pdev) 338 { 339 struct watchdog_device *wdog = platform_get_drvdata(pdev); 340 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 341 342 watchdog_unregister_device(wdog); 343 344 if (imx2_wdt_is_running(wdev)) { 345 imx2_wdt_ping(wdog); 346 dev_crit(&pdev->dev, "Device removed: Expect reboot!\n"); 347 } 348 return 0; 349 } 350 351 static void imx2_wdt_shutdown(struct platform_device *pdev) 352 { 353 struct watchdog_device *wdog = platform_get_drvdata(pdev); 354 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 355 356 if (imx2_wdt_is_running(wdev)) { 357 /* 358 * We are running, configure max timeout before reboot 359 * will take place. 360 */ 361 imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME); 362 imx2_wdt_ping(wdog); 363 dev_crit(&pdev->dev, "Device shutdown: Expect reboot!\n"); 364 } 365 } 366 367 #ifdef CONFIG_PM_SLEEP 368 /* Disable watchdog if it is active or non-active but still running */ 369 static int imx2_wdt_suspend(struct device *dev) 370 { 371 struct watchdog_device *wdog = dev_get_drvdata(dev); 372 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 373 374 /* The watchdog IP block is running */ 375 if (imx2_wdt_is_running(wdev)) { 376 /* 377 * Don't update wdog->timeout, we'll restore the current value 378 * during resume. 379 */ 380 __imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME); 381 imx2_wdt_ping(wdog); 382 } 383 384 clk_disable_unprepare(wdev->clk); 385 386 return 0; 387 } 388 389 /* Enable watchdog and configure it if necessary */ 390 static int imx2_wdt_resume(struct device *dev) 391 { 392 struct watchdog_device *wdog = dev_get_drvdata(dev); 393 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 394 int ret; 395 396 ret = clk_prepare_enable(wdev->clk); 397 if (ret) 398 return ret; 399 400 if (watchdog_active(wdog) && !imx2_wdt_is_running(wdev)) { 401 /* 402 * If the watchdog is still active and resumes 403 * from deep sleep state, need to restart the 404 * watchdog again. 405 */ 406 imx2_wdt_setup(wdog); 407 } 408 if (imx2_wdt_is_running(wdev)) { 409 imx2_wdt_set_timeout(wdog, wdog->timeout); 410 imx2_wdt_ping(wdog); 411 } 412 413 return 0; 414 } 415 #endif 416 417 static SIMPLE_DEV_PM_OPS(imx2_wdt_pm_ops, imx2_wdt_suspend, 418 imx2_wdt_resume); 419 420 static const struct of_device_id imx2_wdt_dt_ids[] = { 421 { .compatible = "fsl,imx21-wdt", }, 422 { /* sentinel */ } 423 }; 424 MODULE_DEVICE_TABLE(of, imx2_wdt_dt_ids); 425 426 static struct platform_driver imx2_wdt_driver = { 427 .remove = __exit_p(imx2_wdt_remove), 428 .shutdown = imx2_wdt_shutdown, 429 .driver = { 430 .name = DRIVER_NAME, 431 .pm = &imx2_wdt_pm_ops, 432 .of_match_table = imx2_wdt_dt_ids, 433 }, 434 }; 435 436 module_platform_driver_probe(imx2_wdt_driver, imx2_wdt_probe); 437 438 MODULE_AUTHOR("Wolfram Sang"); 439 MODULE_DESCRIPTION("Watchdog driver for IMX2 and later"); 440 MODULE_LICENSE("GPL v2"); 441 MODULE_ALIAS("platform:" DRIVER_NAME); 442