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 reg |= WDT_MODE_KEY; 127 iowrite32(reg, wdt_base + WDT_MODE); 128 129 return 0; 130 } 131 132 static int mtk_wdt_start(struct watchdog_device *wdt_dev) 133 { 134 u32 reg; 135 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); 136 void __iomem *wdt_base = mtk_wdt->wdt_base; 137 int ret; 138 139 ret = mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout); 140 if (ret < 0) 141 return ret; 142 143 reg = ioread32(wdt_base + WDT_MODE); 144 reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN); 145 reg |= (WDT_MODE_EN | WDT_MODE_KEY); 146 iowrite32(reg, wdt_base + WDT_MODE); 147 148 return 0; 149 } 150 151 static const struct watchdog_info mtk_wdt_info = { 152 .identity = DRV_NAME, 153 .options = WDIOF_SETTIMEOUT | 154 WDIOF_KEEPALIVEPING | 155 WDIOF_MAGICCLOSE, 156 }; 157 158 static const struct watchdog_ops mtk_wdt_ops = { 159 .owner = THIS_MODULE, 160 .start = mtk_wdt_start, 161 .stop = mtk_wdt_stop, 162 .ping = mtk_wdt_ping, 163 .set_timeout = mtk_wdt_set_timeout, 164 }; 165 166 static int mtk_wdt_probe(struct platform_device *pdev) 167 { 168 struct mtk_wdt_dev *mtk_wdt; 169 struct resource *res; 170 int err; 171 172 mtk_wdt = devm_kzalloc(&pdev->dev, sizeof(*mtk_wdt), GFP_KERNEL); 173 if (!mtk_wdt) 174 return -ENOMEM; 175 176 platform_set_drvdata(pdev, mtk_wdt); 177 178 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 179 mtk_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res); 180 if (IS_ERR(mtk_wdt->wdt_base)) 181 return PTR_ERR(mtk_wdt->wdt_base); 182 183 mtk_wdt->wdt_dev.info = &mtk_wdt_info; 184 mtk_wdt->wdt_dev.ops = &mtk_wdt_ops; 185 mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT; 186 mtk_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT; 187 mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT; 188 mtk_wdt->wdt_dev.parent = &pdev->dev; 189 190 watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, &pdev->dev); 191 watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout); 192 193 watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt); 194 195 mtk_wdt_stop(&mtk_wdt->wdt_dev); 196 197 err = watchdog_register_device(&mtk_wdt->wdt_dev); 198 if (unlikely(err)) 199 return err; 200 201 mtk_wdt->restart_handler.notifier_call = mtk_reset_handler; 202 mtk_wdt->restart_handler.priority = 128; 203 err = register_restart_handler(&mtk_wdt->restart_handler); 204 if (err) 205 dev_warn(&pdev->dev, 206 "cannot register restart handler (err=%d)\n", err); 207 208 dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n", 209 mtk_wdt->wdt_dev.timeout, nowayout); 210 211 return 0; 212 } 213 214 static void mtk_wdt_shutdown(struct platform_device *pdev) 215 { 216 struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev); 217 218 if (watchdog_active(&mtk_wdt->wdt_dev)) 219 mtk_wdt_stop(&mtk_wdt->wdt_dev); 220 } 221 222 static int mtk_wdt_remove(struct platform_device *pdev) 223 { 224 struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev); 225 226 unregister_restart_handler(&mtk_wdt->restart_handler); 227 228 watchdog_unregister_device(&mtk_wdt->wdt_dev); 229 230 return 0; 231 } 232 233 #ifdef CONFIG_PM_SLEEP 234 static int mtk_wdt_suspend(struct device *dev) 235 { 236 struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev); 237 238 if (watchdog_active(&mtk_wdt->wdt_dev)) 239 mtk_wdt_stop(&mtk_wdt->wdt_dev); 240 241 return 0; 242 } 243 244 static int mtk_wdt_resume(struct device *dev) 245 { 246 struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev); 247 248 if (watchdog_active(&mtk_wdt->wdt_dev)) { 249 mtk_wdt_start(&mtk_wdt->wdt_dev); 250 mtk_wdt_ping(&mtk_wdt->wdt_dev); 251 } 252 253 return 0; 254 } 255 #endif 256 257 static const struct of_device_id mtk_wdt_dt_ids[] = { 258 { .compatible = "mediatek,mt6589-wdt" }, 259 { /* sentinel */ } 260 }; 261 MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids); 262 263 static const struct dev_pm_ops mtk_wdt_pm_ops = { 264 SET_SYSTEM_SLEEP_PM_OPS(mtk_wdt_suspend, 265 mtk_wdt_resume) 266 }; 267 268 static struct platform_driver mtk_wdt_driver = { 269 .probe = mtk_wdt_probe, 270 .remove = mtk_wdt_remove, 271 .shutdown = mtk_wdt_shutdown, 272 .driver = { 273 .name = DRV_NAME, 274 .pm = &mtk_wdt_pm_ops, 275 .of_match_table = mtk_wdt_dt_ids, 276 }, 277 }; 278 279 module_platform_driver(mtk_wdt_driver); 280 281 module_param(timeout, uint, 0); 282 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); 283 284 module_param(nowayout, bool, 0); 285 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 286 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 287 288 MODULE_LICENSE("GPL"); 289 MODULE_AUTHOR("Matthias Brugger <matthias.bgg@gmail.com>"); 290 MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver"); 291 MODULE_VERSION(DRV_VERSION); 292