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 { 69 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); 70 void __iomem *wdt_base; 71 72 wdt_base = mtk_wdt->wdt_base; 73 74 while (1) { 75 writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST); 76 mdelay(5); 77 } 78 79 return 0; 80 } 81 82 static int mtk_wdt_ping(struct watchdog_device *wdt_dev) 83 { 84 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); 85 void __iomem *wdt_base = mtk_wdt->wdt_base; 86 87 iowrite32(WDT_RST_RELOAD, wdt_base + WDT_RST); 88 89 return 0; 90 } 91 92 static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev, 93 unsigned int timeout) 94 { 95 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); 96 void __iomem *wdt_base = mtk_wdt->wdt_base; 97 u32 reg; 98 99 wdt_dev->timeout = timeout; 100 101 /* 102 * One bit is the value of 512 ticks 103 * The clock has 32 KHz 104 */ 105 reg = WDT_LENGTH_TIMEOUT(timeout << 6) | WDT_LENGTH_KEY; 106 iowrite32(reg, wdt_base + WDT_LENGTH); 107 108 mtk_wdt_ping(wdt_dev); 109 110 return 0; 111 } 112 113 static int mtk_wdt_stop(struct watchdog_device *wdt_dev) 114 { 115 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); 116 void __iomem *wdt_base = mtk_wdt->wdt_base; 117 u32 reg; 118 119 reg = readl(wdt_base + WDT_MODE); 120 reg &= ~WDT_MODE_EN; 121 reg |= WDT_MODE_KEY; 122 iowrite32(reg, wdt_base + WDT_MODE); 123 124 return 0; 125 } 126 127 static int mtk_wdt_start(struct watchdog_device *wdt_dev) 128 { 129 u32 reg; 130 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); 131 void __iomem *wdt_base = mtk_wdt->wdt_base; 132 int ret; 133 134 ret = mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout); 135 if (ret < 0) 136 return ret; 137 138 reg = ioread32(wdt_base + WDT_MODE); 139 reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN); 140 reg |= (WDT_MODE_EN | WDT_MODE_KEY); 141 iowrite32(reg, wdt_base + WDT_MODE); 142 143 return 0; 144 } 145 146 static const struct watchdog_info mtk_wdt_info = { 147 .identity = DRV_NAME, 148 .options = WDIOF_SETTIMEOUT | 149 WDIOF_KEEPALIVEPING | 150 WDIOF_MAGICCLOSE, 151 }; 152 153 static const struct watchdog_ops mtk_wdt_ops = { 154 .owner = THIS_MODULE, 155 .start = mtk_wdt_start, 156 .stop = mtk_wdt_stop, 157 .ping = mtk_wdt_ping, 158 .set_timeout = mtk_wdt_set_timeout, 159 .restart = mtk_wdt_restart, 160 }; 161 162 static int mtk_wdt_probe(struct platform_device *pdev) 163 { 164 struct mtk_wdt_dev *mtk_wdt; 165 struct resource *res; 166 int err; 167 168 mtk_wdt = devm_kzalloc(&pdev->dev, sizeof(*mtk_wdt), GFP_KERNEL); 169 if (!mtk_wdt) 170 return -ENOMEM; 171 172 platform_set_drvdata(pdev, mtk_wdt); 173 174 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 175 mtk_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res); 176 if (IS_ERR(mtk_wdt->wdt_base)) 177 return PTR_ERR(mtk_wdt->wdt_base); 178 179 mtk_wdt->wdt_dev.info = &mtk_wdt_info; 180 mtk_wdt->wdt_dev.ops = &mtk_wdt_ops; 181 mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT; 182 mtk_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT; 183 mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT; 184 mtk_wdt->wdt_dev.parent = &pdev->dev; 185 186 watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, &pdev->dev); 187 watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout); 188 watchdog_set_restart_priority(&mtk_wdt->wdt_dev, 128); 189 190 watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt); 191 192 mtk_wdt_stop(&mtk_wdt->wdt_dev); 193 194 err = watchdog_register_device(&mtk_wdt->wdt_dev); 195 if (unlikely(err)) 196 return err; 197 198 dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n", 199 mtk_wdt->wdt_dev.timeout, nowayout); 200 201 return 0; 202 } 203 204 static void mtk_wdt_shutdown(struct platform_device *pdev) 205 { 206 struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev); 207 208 if (watchdog_active(&mtk_wdt->wdt_dev)) 209 mtk_wdt_stop(&mtk_wdt->wdt_dev); 210 } 211 212 static int mtk_wdt_remove(struct platform_device *pdev) 213 { 214 struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev); 215 216 watchdog_unregister_device(&mtk_wdt->wdt_dev); 217 218 return 0; 219 } 220 221 #ifdef CONFIG_PM_SLEEP 222 static int mtk_wdt_suspend(struct device *dev) 223 { 224 struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev); 225 226 if (watchdog_active(&mtk_wdt->wdt_dev)) 227 mtk_wdt_stop(&mtk_wdt->wdt_dev); 228 229 return 0; 230 } 231 232 static int mtk_wdt_resume(struct device *dev) 233 { 234 struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev); 235 236 if (watchdog_active(&mtk_wdt->wdt_dev)) { 237 mtk_wdt_start(&mtk_wdt->wdt_dev); 238 mtk_wdt_ping(&mtk_wdt->wdt_dev); 239 } 240 241 return 0; 242 } 243 #endif 244 245 static const struct of_device_id mtk_wdt_dt_ids[] = { 246 { .compatible = "mediatek,mt6589-wdt" }, 247 { /* sentinel */ } 248 }; 249 MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids); 250 251 static const struct dev_pm_ops mtk_wdt_pm_ops = { 252 SET_SYSTEM_SLEEP_PM_OPS(mtk_wdt_suspend, 253 mtk_wdt_resume) 254 }; 255 256 static struct platform_driver mtk_wdt_driver = { 257 .probe = mtk_wdt_probe, 258 .remove = mtk_wdt_remove, 259 .shutdown = mtk_wdt_shutdown, 260 .driver = { 261 .name = DRV_NAME, 262 .pm = &mtk_wdt_pm_ops, 263 .of_match_table = mtk_wdt_dt_ids, 264 }, 265 }; 266 267 module_platform_driver(mtk_wdt_driver); 268 269 module_param(timeout, uint, 0); 270 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); 271 272 module_param(nowayout, bool, 0); 273 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 274 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 275 276 MODULE_LICENSE("GPL"); 277 MODULE_AUTHOR("Matthias Brugger <matthias.bgg@gmail.com>"); 278 MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver"); 279 MODULE_VERSION(DRV_VERSION); 280