1 /* 2 * Mediatek Watchdog Driver 3 * 4 * Copyright (C) 2014 Matthias Brugger 5 * 6 * Matthias Brugger <matthias.bgg@gmail.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * Based on sunxi_wdt.c 19 */ 20 21 #include <linux/err.h> 22 #include <linux/init.h> 23 #include <linux/io.h> 24 #include <linux/kernel.h> 25 #include <linux/module.h> 26 #include <linux/moduleparam.h> 27 #include <linux/of.h> 28 #include <linux/platform_device.h> 29 #include <linux/types.h> 30 #include <linux/watchdog.h> 31 #include <linux/notifier.h> 32 #include <linux/reboot.h> 33 #include <linux/delay.h> 34 35 #define WDT_MAX_TIMEOUT 31 36 #define WDT_MIN_TIMEOUT 1 37 #define WDT_LENGTH_TIMEOUT(n) ((n) << 5) 38 39 #define WDT_LENGTH 0x04 40 #define WDT_LENGTH_KEY 0x8 41 42 #define WDT_RST 0x08 43 #define WDT_RST_RELOAD 0x1971 44 45 #define WDT_MODE 0x00 46 #define WDT_MODE_EN (1 << 0) 47 #define WDT_MODE_EXT_POL_LOW (0 << 1) 48 #define WDT_MODE_EXT_POL_HIGH (1 << 1) 49 #define WDT_MODE_EXRST_EN (1 << 2) 50 #define WDT_MODE_IRQ_EN (1 << 3) 51 #define WDT_MODE_AUTO_START (1 << 4) 52 #define WDT_MODE_DUAL_EN (1 << 6) 53 #define WDT_MODE_KEY 0x22000000 54 55 #define WDT_SWRST 0x14 56 #define WDT_SWRST_KEY 0x1209 57 58 #define DRV_NAME "mtk-wdt" 59 #define DRV_VERSION "1.0" 60 61 static bool nowayout = WATCHDOG_NOWAYOUT; 62 static unsigned int timeout = WDT_MAX_TIMEOUT; 63 64 struct mtk_wdt_dev { 65 struct watchdog_device wdt_dev; 66 void __iomem *wdt_base; 67 struct notifier_block restart_handler; 68 }; 69 70 static int mtk_reset_handler(struct notifier_block *this, unsigned long mode, 71 void *cmd) 72 { 73 struct mtk_wdt_dev *mtk_wdt; 74 void __iomem *wdt_base; 75 76 mtk_wdt = container_of(this, struct mtk_wdt_dev, restart_handler); 77 wdt_base = mtk_wdt->wdt_base; 78 79 while (1) { 80 writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST); 81 mdelay(5); 82 } 83 84 return NOTIFY_DONE; 85 } 86 87 static int mtk_wdt_ping(struct watchdog_device *wdt_dev) 88 { 89 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); 90 void __iomem *wdt_base = mtk_wdt->wdt_base; 91 92 iowrite32(WDT_RST_RELOAD, wdt_base + WDT_RST); 93 94 return 0; 95 } 96 97 static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev, 98 unsigned int timeout) 99 { 100 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); 101 void __iomem *wdt_base = mtk_wdt->wdt_base; 102 u32 reg; 103 104 wdt_dev->timeout = timeout; 105 106 /* 107 * One bit is the value of 512 ticks 108 * The clock has 32 KHz 109 */ 110 reg = WDT_LENGTH_TIMEOUT(timeout << 6) | WDT_LENGTH_KEY; 111 iowrite32(reg, wdt_base + WDT_LENGTH); 112 113 mtk_wdt_ping(wdt_dev); 114 115 return 0; 116 } 117 118 static int mtk_wdt_stop(struct watchdog_device *wdt_dev) 119 { 120 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); 121 void __iomem *wdt_base = mtk_wdt->wdt_base; 122 u32 reg; 123 124 reg = readl(wdt_base + WDT_MODE); 125 reg &= ~WDT_MODE_EN; 126 iowrite32(reg, wdt_base + WDT_MODE); 127 128 return 0; 129 } 130 131 static int mtk_wdt_start(struct watchdog_device *wdt_dev) 132 { 133 u32 reg; 134 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); 135 void __iomem *wdt_base = mtk_wdt->wdt_base; 136 int ret; 137 138 ret = mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout); 139 if (ret < 0) 140 return ret; 141 142 reg = ioread32(wdt_base + WDT_MODE); 143 reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN); 144 reg |= (WDT_MODE_EN | WDT_MODE_KEY); 145 iowrite32(reg, wdt_base + WDT_MODE); 146 147 return 0; 148 } 149 150 static const struct watchdog_info mtk_wdt_info = { 151 .identity = DRV_NAME, 152 .options = WDIOF_SETTIMEOUT | 153 WDIOF_KEEPALIVEPING | 154 WDIOF_MAGICCLOSE, 155 }; 156 157 static const struct watchdog_ops mtk_wdt_ops = { 158 .owner = THIS_MODULE, 159 .start = mtk_wdt_start, 160 .stop = mtk_wdt_stop, 161 .ping = mtk_wdt_ping, 162 .set_timeout = mtk_wdt_set_timeout, 163 }; 164 165 static int mtk_wdt_probe(struct platform_device *pdev) 166 { 167 struct mtk_wdt_dev *mtk_wdt; 168 struct resource *res; 169 int err; 170 171 mtk_wdt = devm_kzalloc(&pdev->dev, sizeof(*mtk_wdt), GFP_KERNEL); 172 if (!mtk_wdt) 173 return -ENOMEM; 174 175 platform_set_drvdata(pdev, mtk_wdt); 176 177 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 178 mtk_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res); 179 if (IS_ERR(mtk_wdt->wdt_base)) 180 return PTR_ERR(mtk_wdt->wdt_base); 181 182 mtk_wdt->wdt_dev.info = &mtk_wdt_info; 183 mtk_wdt->wdt_dev.ops = &mtk_wdt_ops; 184 mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT; 185 mtk_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT; 186 mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT; 187 mtk_wdt->wdt_dev.parent = &pdev->dev; 188 189 watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, &pdev->dev); 190 watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout); 191 192 watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt); 193 194 mtk_wdt_stop(&mtk_wdt->wdt_dev); 195 196 err = watchdog_register_device(&mtk_wdt->wdt_dev); 197 if (unlikely(err)) 198 return err; 199 200 mtk_wdt->restart_handler.notifier_call = mtk_reset_handler; 201 mtk_wdt->restart_handler.priority = 128; 202 err = register_restart_handler(&mtk_wdt->restart_handler); 203 if (err) 204 dev_warn(&pdev->dev, 205 "cannot register restart handler (err=%d)\n", err); 206 207 dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n", 208 mtk_wdt->wdt_dev.timeout, nowayout); 209 210 return 0; 211 } 212 213 static void mtk_wdt_shutdown(struct platform_device *pdev) 214 { 215 struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev); 216 217 if (watchdog_active(&mtk_wdt->wdt_dev)) 218 mtk_wdt_stop(&mtk_wdt->wdt_dev); 219 } 220 221 static int mtk_wdt_remove(struct platform_device *pdev) 222 { 223 struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev); 224 225 unregister_restart_handler(&mtk_wdt->restart_handler); 226 227 watchdog_unregister_device(&mtk_wdt->wdt_dev); 228 229 return 0; 230 } 231 232 #ifdef CONFIG_PM_SLEEP 233 static int mtk_wdt_suspend(struct device *dev) 234 { 235 struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev); 236 237 if (watchdog_active(&mtk_wdt->wdt_dev)) 238 mtk_wdt_stop(&mtk_wdt->wdt_dev); 239 240 return 0; 241 } 242 243 static int mtk_wdt_resume(struct device *dev) 244 { 245 struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev); 246 247 if (watchdog_active(&mtk_wdt->wdt_dev)) { 248 mtk_wdt_start(&mtk_wdt->wdt_dev); 249 mtk_wdt_ping(&mtk_wdt->wdt_dev); 250 } 251 252 return 0; 253 } 254 #endif 255 256 static const struct of_device_id mtk_wdt_dt_ids[] = { 257 { .compatible = "mediatek,mt6589-wdt" }, 258 { /* sentinel */ } 259 }; 260 MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids); 261 262 static const struct dev_pm_ops mtk_wdt_pm_ops = { 263 SET_SYSTEM_SLEEP_PM_OPS(mtk_wdt_suspend, 264 mtk_wdt_resume) 265 }; 266 267 static struct platform_driver mtk_wdt_driver = { 268 .probe = mtk_wdt_probe, 269 .remove = mtk_wdt_remove, 270 .shutdown = mtk_wdt_shutdown, 271 .driver = { 272 .name = DRV_NAME, 273 .pm = &mtk_wdt_pm_ops, 274 .of_match_table = mtk_wdt_dt_ids, 275 }, 276 }; 277 278 module_platform_driver(mtk_wdt_driver); 279 280 module_param(timeout, uint, 0); 281 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); 282 283 module_param(nowayout, bool, 0); 284 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 285 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 286 287 MODULE_LICENSE("GPL"); 288 MODULE_AUTHOR("Matthias Brugger <matthias.bgg@gmail.com>"); 289 MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver"); 290 MODULE_VERSION(DRV_VERSION); 291