drivers/watchdog/mtk_wdt.c

   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);