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/init.h> 26 #include <linux/io.h> 27 #include <linux/jiffies.h> 28 #include <linux/kernel.h> 29 #include <linux/module.h> 30 #include <linux/moduleparam.h> 31 #include <linux/platform_device.h> 32 #include <linux/regmap.h> 33 #include <linux/timer.h> 34 #include <linux/watchdog.h> 35 36 #define DRIVER_NAME "imx2-wdt" 37 38 #define IMX2_WDT_WCR 0x00 /* Control Register */ 39 #define IMX2_WDT_WCR_WT (0xFF << 8) /* -> Watchdog Timeout Field */ 40 #define IMX2_WDT_WCR_WRE (1 << 3) /* -> WDOG Reset Enable */ 41 #define IMX2_WDT_WCR_WDE (1 << 2) /* -> Watchdog Enable */ 42 #define IMX2_WDT_WCR_WDZST (1 << 0) /* -> Watchdog timer Suspend */ 43 44 #define IMX2_WDT_WSR 0x02 /* Service Register */ 45 #define IMX2_WDT_SEQ1 0x5555 /* -> service sequence 1 */ 46 #define IMX2_WDT_SEQ2 0xAAAA /* -> service sequence 2 */ 47 48 #define IMX2_WDT_WRSR 0x04 /* Reset Status Register */ 49 #define IMX2_WDT_WRSR_TOUT (1 << 1) /* -> Reset due to Timeout */ 50 51 #define IMX2_WDT_MAX_TIME 128 52 #define IMX2_WDT_DEFAULT_TIME 60 /* in seconds */ 53 54 #define WDOG_SEC_TO_COUNT(s) ((s * 2 - 1) << 8) 55 56 struct imx2_wdt_device { 57 struct clk *clk; 58 struct regmap *regmap; 59 struct timer_list timer; /* Pings the watchdog when closed */ 60 struct watchdog_device wdog; 61 }; 62 63 static bool nowayout = WATCHDOG_NOWAYOUT; 64 module_param(nowayout, bool, 0); 65 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 66 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 67 68 69 static unsigned timeout = IMX2_WDT_DEFAULT_TIME; 70 module_param(timeout, uint, 0); 71 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" 72 __MODULE_STRING(IMX2_WDT_DEFAULT_TIME) ")"); 73 74 static const struct watchdog_info imx2_wdt_info = { 75 .identity = "imx2+ watchdog", 76 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, 77 }; 78 79 static inline void imx2_wdt_setup(struct watchdog_device *wdog) 80 { 81 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 82 u32 val; 83 84 regmap_read(wdev->regmap, IMX2_WDT_WCR, &val); 85 86 /* Suspend timer in low power mode, write once-only */ 87 val |= IMX2_WDT_WCR_WDZST; 88 /* Strip the old watchdog Time-Out value */ 89 val &= ~IMX2_WDT_WCR_WT; 90 /* Generate reset if WDOG times out */ 91 val &= ~IMX2_WDT_WCR_WRE; 92 /* Keep Watchdog Disabled */ 93 val &= ~IMX2_WDT_WCR_WDE; 94 /* Set the watchdog's Time-Out value */ 95 val |= WDOG_SEC_TO_COUNT(wdog->timeout); 96 97 regmap_write(wdev->regmap, IMX2_WDT_WCR, val); 98 99 /* enable the watchdog */ 100 val |= IMX2_WDT_WCR_WDE; 101 regmap_write(wdev->regmap, IMX2_WDT_WCR, val); 102 } 103 104 static inline bool imx2_wdt_is_running(struct imx2_wdt_device *wdev) 105 { 106 u32 val; 107 108 regmap_read(wdev->regmap, IMX2_WDT_WCR, &val); 109 110 return val & IMX2_WDT_WCR_WDE; 111 } 112 113 static int imx2_wdt_ping(struct watchdog_device *wdog) 114 { 115 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 116 117 regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ1); 118 regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ2); 119 return 0; 120 } 121 122 static void imx2_wdt_timer_ping(unsigned long arg) 123 { 124 struct watchdog_device *wdog = (struct watchdog_device *)arg; 125 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 126 127 /* ping it every wdog->timeout / 2 seconds to prevent reboot */ 128 imx2_wdt_ping(wdog); 129 mod_timer(&wdev->timer, jiffies + wdog->timeout * HZ / 2); 130 } 131 132 static int imx2_wdt_set_timeout(struct watchdog_device *wdog, 133 unsigned int new_timeout) 134 { 135 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 136 137 regmap_update_bits(wdev->regmap, IMX2_WDT_WCR, IMX2_WDT_WCR_WT, 138 WDOG_SEC_TO_COUNT(new_timeout)); 139 return 0; 140 } 141 142 static int imx2_wdt_start(struct watchdog_device *wdog) 143 { 144 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 145 146 if (imx2_wdt_is_running(wdev)) { 147 /* delete the timer that pings the watchdog after close */ 148 del_timer_sync(&wdev->timer); 149 imx2_wdt_set_timeout(wdog, wdog->timeout); 150 } else 151 imx2_wdt_setup(wdog); 152 153 return imx2_wdt_ping(wdog); 154 } 155 156 static int imx2_wdt_stop(struct watchdog_device *wdog) 157 { 158 /* 159 * We don't need a clk_disable, it cannot be disabled once started. 160 * We use a timer to ping the watchdog while /dev/watchdog is closed 161 */ 162 imx2_wdt_timer_ping((unsigned long)wdog); 163 return 0; 164 } 165 166 static inline void imx2_wdt_ping_if_active(struct watchdog_device *wdog) 167 { 168 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 169 170 if (imx2_wdt_is_running(wdev)) { 171 imx2_wdt_set_timeout(wdog, wdog->timeout); 172 imx2_wdt_timer_ping((unsigned long)wdog); 173 } 174 } 175 176 static struct watchdog_ops imx2_wdt_ops = { 177 .owner = THIS_MODULE, 178 .start = imx2_wdt_start, 179 .stop = imx2_wdt_stop, 180 .ping = imx2_wdt_ping, 181 .set_timeout = imx2_wdt_set_timeout, 182 }; 183 184 static struct regmap_config imx2_wdt_regmap_config = { 185 .reg_bits = 16, 186 .reg_stride = 2, 187 .val_bits = 16, 188 .max_register = 0x8, 189 }; 190 191 static int __init imx2_wdt_probe(struct platform_device *pdev) 192 { 193 struct imx2_wdt_device *wdev; 194 struct watchdog_device *wdog; 195 struct resource *res; 196 void __iomem *base; 197 int ret; 198 u32 val; 199 200 wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL); 201 if (!wdev) 202 return -ENOMEM; 203 204 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 205 base = devm_ioremap_resource(&pdev->dev, res); 206 if (IS_ERR(base)) 207 return PTR_ERR(base); 208 209 wdev->regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base, 210 &imx2_wdt_regmap_config); 211 if (IS_ERR(wdev->regmap)) { 212 dev_err(&pdev->dev, "regmap init failed\n"); 213 return PTR_ERR(wdev->regmap); 214 } 215 216 wdev->clk = devm_clk_get(&pdev->dev, NULL); 217 if (IS_ERR(wdev->clk)) { 218 dev_err(&pdev->dev, "can't get Watchdog clock\n"); 219 return PTR_ERR(wdev->clk); 220 } 221 222 wdog = &wdev->wdog; 223 wdog->info = &imx2_wdt_info; 224 wdog->ops = &imx2_wdt_ops; 225 wdog->min_timeout = 1; 226 wdog->max_timeout = IMX2_WDT_MAX_TIME; 227 228 clk_prepare_enable(wdev->clk); 229 230 regmap_read(wdev->regmap, IMX2_WDT_WRSR, &val); 231 wdog->bootstatus = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0; 232 233 wdog->timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME); 234 if (wdog->timeout != timeout) 235 dev_warn(&pdev->dev, "Initial timeout out of range! Clamped from %u to %u\n", 236 timeout, wdog->timeout); 237 238 platform_set_drvdata(pdev, wdog); 239 watchdog_set_drvdata(wdog, wdev); 240 watchdog_set_nowayout(wdog, nowayout); 241 watchdog_init_timeout(wdog, timeout, &pdev->dev); 242 243 setup_timer(&wdev->timer, imx2_wdt_timer_ping, (unsigned long)wdog); 244 245 imx2_wdt_ping_if_active(wdog); 246 247 ret = watchdog_register_device(wdog); 248 if (ret) { 249 dev_err(&pdev->dev, "cannot register watchdog device\n"); 250 return ret; 251 } 252 253 dev_info(&pdev->dev, "timeout %d sec (nowayout=%d)\n", 254 wdog->timeout, nowayout); 255 256 return 0; 257 } 258 259 static int __exit imx2_wdt_remove(struct platform_device *pdev) 260 { 261 struct watchdog_device *wdog = platform_get_drvdata(pdev); 262 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 263 264 watchdog_unregister_device(wdog); 265 266 if (imx2_wdt_is_running(wdev)) { 267 del_timer_sync(&wdev->timer); 268 imx2_wdt_ping(wdog); 269 dev_crit(&pdev->dev, "Device removed: Expect reboot!\n"); 270 } 271 return 0; 272 } 273 274 static void imx2_wdt_shutdown(struct platform_device *pdev) 275 { 276 struct watchdog_device *wdog = platform_get_drvdata(pdev); 277 struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); 278 279 if (imx2_wdt_is_running(wdev)) { 280 /* 281 * We are running, we need to delete the timer but will 282 * give max timeout before reboot will take place 283 */ 284 del_timer_sync(&wdev->timer); 285 imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME); 286 imx2_wdt_ping(wdog); 287 dev_crit(&pdev->dev, "Device shutdown: Expect reboot!\n"); 288 } 289 } 290 291 static const struct of_device_id imx2_wdt_dt_ids[] = { 292 { .compatible = "fsl,imx21-wdt", }, 293 { /* sentinel */ } 294 }; 295 MODULE_DEVICE_TABLE(of, imx2_wdt_dt_ids); 296 297 static struct platform_driver imx2_wdt_driver = { 298 .remove = __exit_p(imx2_wdt_remove), 299 .shutdown = imx2_wdt_shutdown, 300 .driver = { 301 .name = DRIVER_NAME, 302 .owner = THIS_MODULE, 303 .of_match_table = imx2_wdt_dt_ids, 304 }, 305 }; 306 307 module_platform_driver_probe(imx2_wdt_driver, imx2_wdt_probe); 308 309 MODULE_AUTHOR("Wolfram Sang"); 310 MODULE_DESCRIPTION("Watchdog driver for IMX2 and later"); 311 MODULE_LICENSE("GPL v2"); 312 MODULE_ALIAS("platform:" DRIVER_NAME); 313