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/delay.h> 32 33 #define WDT_MAX_TIMEOUT 31 34 #define WDT_MIN_TIMEOUT 1 35 #define WDT_LENGTH_TIMEOUT(n) ((n) << 5) 36 37 #define WDT_LENGTH 0x04 38 #define WDT_LENGTH_KEY 0x8 39 40 #define WDT_RST 0x08 41 #define WDT_RST_RELOAD 0x1971 42 43 #define WDT_MODE 0x00 44 #define WDT_MODE_EN (1 << 0) 45 #define WDT_MODE_EXT_POL_LOW (0 << 1) 46 #define WDT_MODE_EXT_POL_HIGH (1 << 1) 47 #define WDT_MODE_EXRST_EN (1 << 2) 48 #define WDT_MODE_IRQ_EN (1 << 3) 49 #define WDT_MODE_AUTO_START (1 << 4) 50 #define WDT_MODE_DUAL_EN (1 << 6) 51 #define WDT_MODE_KEY 0x22000000 52 53 #define WDT_SWRST 0x14 54 #define WDT_SWRST_KEY 0x1209 55 56 #define DRV_NAME "mtk-wdt" 57 #define DRV_VERSION "1.0" 58 59 static bool nowayout = WATCHDOG_NOWAYOUT; 60 static unsigned int timeout = WDT_MAX_TIMEOUT; 61 62 struct mtk_wdt_dev { 63 struct watchdog_device wdt_dev; 64 void __iomem *wdt_base; 65 }; 66 67 static int mtk_wdt_restart(struct watchdog_device *wdt_dev, 68 unsigned long action, void *data) 69 { 70 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); 71 void __iomem *wdt_base; 72 73 wdt_base = mtk_wdt->wdt_base; 74 75 while (1) { 76 writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST); 77 mdelay(5); 78 } 79 80 return 0; 81 } 82 83 static int mtk_wdt_ping(struct watchdog_device *wdt_dev) 84 { 85 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); 86 void __iomem *wdt_base = mtk_wdt->wdt_base; 87 88 iowrite32(WDT_RST_RELOAD, wdt_base + WDT_RST); 89 90 return 0; 91 } 92 93 static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev, 94 unsigned int timeout) 95 { 96 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); 97 void __iomem *wdt_base = mtk_wdt->wdt_base; 98 u32 reg; 99 100 wdt_dev->timeout = timeout; 101 102 /* 103 * One bit is the value of 512 ticks 104 * The clock has 32 KHz 105 */ 106 reg = WDT_LENGTH_TIMEOUT(timeout << 6) | WDT_LENGTH_KEY; 107 iowrite32(reg, wdt_base + WDT_LENGTH); 108 109 mtk_wdt_ping(wdt_dev); 110 111 return 0; 112 } 113 114 static int mtk_wdt_stop(struct watchdog_device *wdt_dev) 115 { 116 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); 117 void __iomem *wdt_base = mtk_wdt->wdt_base; 118 u32 reg; 119 120 reg = readl(wdt_base + WDT_MODE); 121 reg &= ~WDT_MODE_EN; 122 reg |= WDT_MODE_KEY; 123 iowrite32(reg, wdt_base + WDT_MODE); 124 125 return 0; 126 } 127 128 static int mtk_wdt_start(struct watchdog_device *wdt_dev) 129 { 130 u32 reg; 131 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); 132 void __iomem *wdt_base = mtk_wdt->wdt_base; 133 int ret; 134 135 ret = mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout); 136 if (ret < 0) 137 return ret; 138 139 reg = ioread32(wdt_base + WDT_MODE); 140 reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN); 141 reg |= (WDT_MODE_EN | WDT_MODE_KEY); 142 iowrite32(reg, wdt_base + WDT_MODE); 143 144 return 0; 145 } 146 147 static const struct watchdog_info mtk_wdt_info = { 148 .identity = DRV_NAME, 149 .options = WDIOF_SETTIMEOUT | 150 WDIOF_KEEPALIVEPING | 151 WDIOF_MAGICCLOSE, 152 }; 153 154 static const struct watchdog_ops mtk_wdt_ops = { 155 .owner = THIS_MODULE, 156 .start = mtk_wdt_start, 157 .stop = mtk_wdt_stop, 158 .ping = mtk_wdt_ping, 159 .set_timeout = mtk_wdt_set_timeout, 160 .restart = mtk_wdt_restart, 161 }; 162 163 static int mtk_wdt_probe(struct platform_device *pdev) 164 { 165 struct mtk_wdt_dev *mtk_wdt; 166 struct resource *res; 167 int err; 168 169 mtk_wdt = devm_kzalloc(&pdev->dev, sizeof(*mtk_wdt), GFP_KERNEL); 170 if (!mtk_wdt) 171 return -ENOMEM; 172 173 platform_set_drvdata(pdev, mtk_wdt); 174 175 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 176 mtk_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res); 177 if (IS_ERR(mtk_wdt->wdt_base)) 178 return PTR_ERR(mtk_wdt->wdt_base); 179 180 mtk_wdt->wdt_dev.info = &mtk_wdt_info; 181 mtk_wdt->wdt_dev.ops = &mtk_wdt_ops; 182 mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT; 183 mtk_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT; 184 mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT; 185 mtk_wdt->wdt_dev.parent = &pdev->dev; 186 187 watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, &pdev->dev); 188 watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout); 189 watchdog_set_restart_priority(&mtk_wdt->wdt_dev, 128); 190 191 watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt); 192 193 mtk_wdt_stop(&mtk_wdt->wdt_dev); 194 195 err = watchdog_register_device(&mtk_wdt->wdt_dev); 196 if (unlikely(err)) 197 return err; 198 199 dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n", 200 mtk_wdt->wdt_dev.timeout, nowayout); 201 202 return 0; 203 } 204 205 static void mtk_wdt_shutdown(struct platform_device *pdev) 206 { 207 struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev); 208 209 if (watchdog_active(&mtk_wdt->wdt_dev)) 210 mtk_wdt_stop(&mtk_wdt->wdt_dev); 211 } 212 213 static int mtk_wdt_remove(struct platform_device *pdev) 214 { 215 struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev); 216 217 watchdog_unregister_device(&mtk_wdt->wdt_dev); 218 219 return 0; 220 } 221 222 #ifdef CONFIG_PM_SLEEP 223 static int mtk_wdt_suspend(struct device *dev) 224 { 225 struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev); 226 227 if (watchdog_active(&mtk_wdt->wdt_dev)) 228 mtk_wdt_stop(&mtk_wdt->wdt_dev); 229 230 return 0; 231 } 232 233 static int mtk_wdt_resume(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_start(&mtk_wdt->wdt_dev); 239 mtk_wdt_ping(&mtk_wdt->wdt_dev); 240 } 241 242 return 0; 243 } 244 #endif 245 246 static const struct of_device_id mtk_wdt_dt_ids[] = { 247 { .compatible = "mediatek,mt6589-wdt" }, 248 { /* sentinel */ } 249 }; 250 MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids); 251 252 static const struct dev_pm_ops mtk_wdt_pm_ops = { 253 SET_SYSTEM_SLEEP_PM_OPS(mtk_wdt_suspend, 254 mtk_wdt_resume) 255 }; 256 257 static struct platform_driver mtk_wdt_driver = { 258 .probe = mtk_wdt_probe, 259 .remove = mtk_wdt_remove, 260 .shutdown = mtk_wdt_shutdown, 261 .driver = { 262 .name = DRV_NAME, 263 .pm = &mtk_wdt_pm_ops, 264 .of_match_table = mtk_wdt_dt_ids, 265 }, 266 }; 267 268 module_platform_driver(mtk_wdt_driver); 269 270 module_param(timeout, uint, 0); 271 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); 272 273 module_param(nowayout, bool, 0); 274 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 275 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 276 277 MODULE_LICENSE("GPL"); 278 MODULE_AUTHOR("Matthias Brugger <matthias.bgg@gmail.com>"); 279 MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver"); 280 MODULE_VERSION(DRV_VERSION); 281