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 = IMX2_WDT_DEFAULT_TIME; 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 int 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 wdog->timeout = new_timeout; 178 179 regmap_update_bits(wdev->regmap, IMX2_WDT_WCR, IMX2_WDT_WCR_WT, 180 WDOG_SEC_TO_COUNT(new_timeout)); 181 return 0; 182 } 183 184 static int imx2_wdt_set_pretimeout(struct watchdog_device *wdog, 185 unsigned int new_pretimeout) 186 { 187 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 188 189 if (new_pretimeout >= IMX2_WDT_MAX_TIME) 190 return -EINVAL; 191 192 wdog->pretimeout = new_pretimeout; 193 194 regmap_update_bits(wdev->regmap, IMX2_WDT_WICR, 195 IMX2_WDT_WICR_WIE | IMX2_WDT_WICR_WICT, 196 IMX2_WDT_WICR_WIE | (new_pretimeout << 1)); 197 return 0; 198 } 199 200 static irqreturn_t imx2_wdt_isr(int irq, void *wdog_arg) 201 { 202 struct watchdog_device *wdog = wdog_arg; 203 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 204 205 regmap_write_bits(wdev->regmap, IMX2_WDT_WICR, 206 IMX2_WDT_WICR_WTIS, IMX2_WDT_WICR_WTIS); 207 208 watchdog_notify_pretimeout(wdog); 209 210 return IRQ_HANDLED; 211 } 212 213 static int imx2_wdt_start(struct watchdog_device *wdog) 214 { 215 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 216 217 if (imx2_wdt_is_running(wdev)) 218 imx2_wdt_set_timeout(wdog, wdog->timeout); 219 else 220 imx2_wdt_setup(wdog); 221 222 set_bit(WDOG_HW_RUNNING, &wdog->status); 223 224 return imx2_wdt_ping(wdog); 225 } 226 227 static const struct watchdog_ops imx2_wdt_ops = { 228 .owner = THIS_MODULE, 229 .start = imx2_wdt_start, 230 .ping = imx2_wdt_ping, 231 .set_timeout = imx2_wdt_set_timeout, 232 .set_pretimeout = imx2_wdt_set_pretimeout, 233 .restart = imx2_wdt_restart, 234 }; 235 236 static const struct regmap_config imx2_wdt_regmap_config = { 237 .reg_bits = 16, 238 .reg_stride = 2, 239 .val_bits = 16, 240 .max_register = 0x8, 241 }; 242 243 static int __init imx2_wdt_probe(struct platform_device *pdev) 244 { 245 struct imx2_wdt_device *wdev; 246 struct watchdog_device *wdog; 247 struct resource *res; 248 void __iomem *base; 249 int ret; 250 u32 val; 251 252 wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL); 253 if (!wdev) 254 return -ENOMEM; 255 256 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 257 base = devm_ioremap_resource(&pdev->dev, res); 258 if (IS_ERR(base)) 259 return PTR_ERR(base); 260 261 wdev->regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base, 262 &imx2_wdt_regmap_config); 263 if (IS_ERR(wdev->regmap)) { 264 dev_err(&pdev->dev, "regmap init failed\n"); 265 return PTR_ERR(wdev->regmap); 266 } 267 268 wdev->clk = devm_clk_get(&pdev->dev, NULL); 269 if (IS_ERR(wdev->clk)) { 270 dev_err(&pdev->dev, "can't get Watchdog clock\n"); 271 return PTR_ERR(wdev->clk); 272 } 273 274 wdog = &wdev->wdog; 275 wdog->info = &imx2_wdt_info; 276 wdog->ops = &imx2_wdt_ops; 277 wdog->min_timeout = 1; 278 wdog->max_hw_heartbeat_ms = IMX2_WDT_MAX_TIME * 1000; 279 wdog->parent = &pdev->dev; 280 281 ret = platform_get_irq(pdev, 0); 282 if (ret > 0) 283 if (!devm_request_irq(&pdev->dev, ret, imx2_wdt_isr, 0, 284 dev_name(&pdev->dev), wdog)) 285 wdog->info = &imx2_wdt_pretimeout_info; 286 287 ret = clk_prepare_enable(wdev->clk); 288 if (ret) 289 return ret; 290 291 regmap_read(wdev->regmap, IMX2_WDT_WRSR, &val); 292 wdog->bootstatus = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0; 293 294 wdev->ext_reset = of_property_read_bool(pdev->dev.of_node, 295 "fsl,ext-reset-output"); 296 wdog->timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME); 297 if (wdog->timeout != timeout) 298 dev_warn(&pdev->dev, "Initial timeout out of range! Clamped from %u to %u\n", 299 timeout, wdog->timeout); 300 301 platform_set_drvdata(pdev, wdog); 302 watchdog_set_drvdata(wdog, wdev); 303 watchdog_set_nowayout(wdog, nowayout); 304 watchdog_set_restart_priority(wdog, 128); 305 watchdog_init_timeout(wdog, timeout, &pdev->dev); 306 307 if (imx2_wdt_is_running(wdev)) { 308 imx2_wdt_set_timeout(wdog, wdog->timeout); 309 set_bit(WDOG_HW_RUNNING, &wdog->status); 310 } 311 312 /* 313 * Disable the watchdog power down counter at boot. Otherwise the power 314 * down counter will pull down the #WDOG interrupt line for one clock 315 * cycle. 316 */ 317 regmap_write(wdev->regmap, IMX2_WDT_WMCR, 0); 318 319 ret = watchdog_register_device(wdog); 320 if (ret) { 321 dev_err(&pdev->dev, "cannot register watchdog device\n"); 322 goto disable_clk; 323 } 324 325 dev_info(&pdev->dev, "timeout %d sec (nowayout=%d)\n", 326 wdog->timeout, nowayout); 327 328 return 0; 329 330 disable_clk: 331 clk_disable_unprepare(wdev->clk); 332 return ret; 333 } 334 335 static int __exit imx2_wdt_remove(struct platform_device *pdev) 336 { 337 struct watchdog_device *wdog = platform_get_drvdata(pdev); 338 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 339 340 watchdog_unregister_device(wdog); 341 342 if (imx2_wdt_is_running(wdev)) { 343 imx2_wdt_ping(wdog); 344 dev_crit(&pdev->dev, "Device removed: Expect reboot!\n"); 345 } 346 return 0; 347 } 348 349 static void imx2_wdt_shutdown(struct platform_device *pdev) 350 { 351 struct watchdog_device *wdog = platform_get_drvdata(pdev); 352 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 353 354 if (imx2_wdt_is_running(wdev)) { 355 /* 356 * We are running, configure max timeout before reboot 357 * will take place. 358 */ 359 imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME); 360 imx2_wdt_ping(wdog); 361 dev_crit(&pdev->dev, "Device shutdown: Expect reboot!\n"); 362 } 363 } 364 365 #ifdef CONFIG_PM_SLEEP 366 /* Disable watchdog if it is active or non-active but still running */ 367 static int imx2_wdt_suspend(struct device *dev) 368 { 369 struct watchdog_device *wdog = dev_get_drvdata(dev); 370 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 371 372 /* The watchdog IP block is running */ 373 if (imx2_wdt_is_running(wdev)) { 374 imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME); 375 imx2_wdt_ping(wdog); 376 } 377 378 clk_disable_unprepare(wdev->clk); 379 380 return 0; 381 } 382 383 /* Enable watchdog and configure it if necessary */ 384 static int imx2_wdt_resume(struct device *dev) 385 { 386 struct watchdog_device *wdog = dev_get_drvdata(dev); 387 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 388 int ret; 389 390 ret = clk_prepare_enable(wdev->clk); 391 if (ret) 392 return ret; 393 394 if (watchdog_active(wdog) && !imx2_wdt_is_running(wdev)) { 395 /* 396 * If the watchdog is still active and resumes 397 * from deep sleep state, need to restart the 398 * watchdog again. 399 */ 400 imx2_wdt_setup(wdog); 401 } 402 if (imx2_wdt_is_running(wdev)) { 403 imx2_wdt_set_timeout(wdog, wdog->timeout); 404 imx2_wdt_ping(wdog); 405 } 406 407 return 0; 408 } 409 #endif 410 411 static SIMPLE_DEV_PM_OPS(imx2_wdt_pm_ops, imx2_wdt_suspend, 412 imx2_wdt_resume); 413 414 static const struct of_device_id imx2_wdt_dt_ids[] = { 415 { .compatible = "fsl,imx21-wdt", }, 416 { /* sentinel */ } 417 }; 418 MODULE_DEVICE_TABLE(of, imx2_wdt_dt_ids); 419 420 static struct platform_driver imx2_wdt_driver = { 421 .remove = __exit_p(imx2_wdt_remove), 422 .shutdown = imx2_wdt_shutdown, 423 .driver = { 424 .name = DRIVER_NAME, 425 .pm = &imx2_wdt_pm_ops, 426 .of_match_table = imx2_wdt_dt_ids, 427 }, 428 }; 429 430 module_platform_driver_probe(imx2_wdt_driver, imx2_wdt_probe); 431 432 MODULE_AUTHOR("Wolfram Sang"); 433 MODULE_DESCRIPTION("Watchdog driver for IMX2 and later"); 434 MODULE_LICENSE("GPL v2"); 435 MODULE_ALIAS("platform:" DRIVER_NAME); 436