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 {
  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);