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/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);