drivers/watchdog/sunxi_wdt.c

   1 /*
   2  *      sunxi Watchdog Driver
   3  *
   4  *      Copyright (c) 2013 Carlo Caione
   5  *                    2012 Henrik Nordstrom
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License
   9  *      as published by the Free Software Foundation; either version
  10  *      2 of the License, or (at your option) any later version.
  11  *
  12  *      Based on xen_wdt.c
  13  *      (c) Copyright 2010 Novell, Inc.
  14  */
  15
  16 #include <linux/clk.h>
  17 #include <linux/delay.h>
  18 #include <linux/err.h>
  19 #include <linux/init.h>
  20 #include <linux/io.h>
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/moduleparam.h>
  24 #include <linux/of.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/reboot.h>
  27 #include <linux/types.h>
  28 #include <linux/watchdog.h>
  29
  30 #include <asm/system_misc.h>
  31
  32 #define WDT_MAX_TIMEOUT         16
  33 #define WDT_MIN_TIMEOUT         1
  34 #define WDT_MODE_TIMEOUT(n)     ((n) << 3)
  35 #define WDT_TIMEOUT_MASK        WDT_MODE_TIMEOUT(0x0F)
  36
  37 #define WDT_CTRL                0x00
  38 #define WDT_CTRL_RELOAD         ((1 << 0) | (0x0a57 << 1))
  39
  40 #define WDT_MODE                0x04
  41 #define WDT_MODE_EN             (1 << 0)
  42 #define WDT_MODE_RST_EN         (1 << 1)
  43
  44 #define DRV_NAME                "sunxi-wdt"
  45 #define DRV_VERSION             "1.0"
  46
  47 static bool nowayout = WATCHDOG_NOWAYOUT;
  48 static unsigned int timeout = WDT_MAX_TIMEOUT;
  49
  50 struct sunxi_wdt_dev {
  51         struct watchdog_device wdt_dev;
  52         void __iomem *wdt_base;
  53 };
  54
  55 /*
  56  * wdt_timeout_map maps the watchdog timer interval value in seconds to
  57  * the value of the register WDT_MODE bit 3:6
  58  *
  59  * [timeout seconds] = register value
  60  *
  61  */
  62
  63 static const int wdt_timeout_map[] = {
  64         [1] = 0x1,  /* 1s  */
  65         [2] = 0x2,  /* 2s  */
  66         [3] = 0x3,  /* 3s  */
  67         [4] = 0x4,  /* 4s  */
  68         [5] = 0x5,  /* 5s  */
  69         [6] = 0x6,  /* 6s  */
  70         [8] = 0x7,  /* 8s  */
  71         [10] = 0x8, /* 10s */
  72         [12] = 0x9, /* 12s */
  73         [14] = 0xA, /* 14s */
  74         [16] = 0xB, /* 16s */
  75 };
  76
  77 static void __iomem *reboot_wdt_base;
  78
  79 static void sun4i_wdt_restart(enum reboot_mode mode, const char *cmd)
  80 {
  81         /* Enable timer and set reset bit in the watchdog */
  82         writel(WDT_MODE_EN | WDT_MODE_RST_EN, reboot_wdt_base + WDT_MODE);
  83
  84         /*
  85          * Restart the watchdog. The default (and lowest) interval
  86          * value for the watchdog is 0.5s.
  87          */
  88         writel(WDT_CTRL_RELOAD, reboot_wdt_base + WDT_CTRL);
  89
  90         while (1) {
  91                 mdelay(5);
  92                 writel(WDT_MODE_EN | WDT_MODE_RST_EN,
  93                        reboot_wdt_base + WDT_MODE);
  94         }
  95 }
  96
  97 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev)
  98 {
  99         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 100         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 101
 102         iowrite32(WDT_CTRL_RELOAD, wdt_base + WDT_CTRL);
 103
 104         return 0;
 105 }
 106
 107 static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev,
 108                 unsigned int timeout)
 109 {
 110         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 111         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 112         u32 reg;
 113
 114         if (wdt_timeout_map[timeout] == 0)
 115                 timeout++;
 116
 117         sunxi_wdt->wdt_dev.timeout = timeout;
 118
 119         reg = ioread32(wdt_base + WDT_MODE);
 120         reg &= ~WDT_TIMEOUT_MASK;
 121         reg |= WDT_MODE_TIMEOUT(wdt_timeout_map[timeout]);
 122         iowrite32(reg, wdt_base + WDT_MODE);
 123
 124         sunxi_wdt_ping(wdt_dev);
 125
 126         return 0;
 127 }
 128
 129 static int sunxi_wdt_stop(struct watchdog_device *wdt_dev)
 130 {
 131         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 132         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 133
 134         iowrite32(0, wdt_base + WDT_MODE);
 135
 136         return 0;
 137 }
 138
 139 static int sunxi_wdt_start(struct watchdog_device *wdt_dev)
 140 {
 141         u32 reg;
 142         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 143         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 144         int ret;
 145
 146         ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev,
 147                         sunxi_wdt->wdt_dev.timeout);
 148         if (ret < 0)
 149                 return ret;
 150
 151         reg = ioread32(wdt_base + WDT_MODE);
 152         reg |= (WDT_MODE_RST_EN | WDT_MODE_EN);
 153         iowrite32(reg, wdt_base + WDT_MODE);
 154
 155         return 0;
 156 }
 157
 158 static const struct watchdog_info sunxi_wdt_info = {
 159         .identity       = DRV_NAME,
 160         .options        = WDIOF_SETTIMEOUT |
 161                           WDIOF_KEEPALIVEPING |
 162                           WDIOF_MAGICCLOSE,
 163 };
 164
 165 static const struct watchdog_ops sunxi_wdt_ops = {
 166         .owner          = THIS_MODULE,
 167         .start          = sunxi_wdt_start,
 168         .stop           = sunxi_wdt_stop,
 169         .ping           = sunxi_wdt_ping,
 170         .set_timeout    = sunxi_wdt_set_timeout,
 171 };
 172
 173 static int sunxi_wdt_probe(struct platform_device *pdev)
 174 {
 175         struct sunxi_wdt_dev *sunxi_wdt;
 176         struct resource *res;
 177         int err;
 178
 179         sunxi_wdt = devm_kzalloc(&pdev->dev, sizeof(*sunxi_wdt), GFP_KERNEL);
 180         if (!sunxi_wdt)
 181                 return -EINVAL;
 182
 183         platform_set_drvdata(pdev, sunxi_wdt);
 184
 185         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 186         sunxi_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
 187         if (IS_ERR(sunxi_wdt->wdt_base))
 188                 return PTR_ERR(sunxi_wdt->wdt_base);
 189
 190         sunxi_wdt->wdt_dev.info = &sunxi_wdt_info;
 191         sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops;
 192         sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
 193         sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
 194         sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
 195         sunxi_wdt->wdt_dev.parent = &pdev->dev;
 196
 197         watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, &pdev->dev);
 198         watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout);
 199
 200         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt);
 201
 202         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
 203
 204         err = watchdog_register_device(&sunxi_wdt->wdt_dev);
 205         if (unlikely(err))
 206                 return err;
 207
 208         reboot_wdt_base = sunxi_wdt->wdt_base;
 209         arm_pm_restart = sun4i_wdt_restart;
 210
 211         dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
 212                         sunxi_wdt->wdt_dev.timeout, nowayout);
 213
 214         return 0;
 215 }
 216
 217 static int sunxi_wdt_remove(struct platform_device *pdev)
 218 {
 219         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
 220
 221         arm_pm_restart = NULL;
 222
 223         watchdog_unregister_device(&sunxi_wdt->wdt_dev);
 224         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, NULL);
 225
 226         return 0;
 227 }
 228
 229 static void sunxi_wdt_shutdown(struct platform_device *pdev)
 230 {
 231         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
 232
 233         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
 234 }
 235
 236 static const struct of_device_id sunxi_wdt_dt_ids[] = {
 237         { .compatible = "allwinner,sun4i-a10-wdt" },
 238         { /* sentinel */ }
 239 };
 240 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
 241
 242 static struct platform_driver sunxi_wdt_driver = {
 243         .probe          = sunxi_wdt_probe,
 244         .remove         = sunxi_wdt_remove,
 245         .shutdown       = sunxi_wdt_shutdown,
 246         .driver         = {
 247                 .owner          = THIS_MODULE,
 248                 .name           = DRV_NAME,
 249                 .of_match_table = sunxi_wdt_dt_ids,
 250         },
 251 };
 252
 253 module_platform_driver(sunxi_wdt_driver);
 254
 255 module_param(timeout, uint, 0);
 256 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
 257
 258 module_param(nowayout, bool, 0);
 259 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
 260                 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 261
 262 MODULE_LICENSE("GPL");
 263 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
 264 MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
 265 MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
 266 MODULE_VERSION(DRV_VERSION);