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/err.h>
  18 #include <linux/init.h>
  19 #include <linux/io.h>
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/moduleparam.h>
  23 #include <linux/of.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/types.h>
  26 #include <linux/watchdog.h>
  27
  28 #define WDT_MAX_TIMEOUT         16
  29 #define WDT_MIN_TIMEOUT         1
  30 #define WDT_MODE_TIMEOUT(n)     ((n) << 3)
  31 #define WDT_TIMEOUT_MASK        WDT_MODE_TIMEOUT(0x0F)
  32
  33 #define WDT_CTRL                0x00
  34 #define WDT_CTRL_RELOAD         ((1 << 0) | (0x0a57 << 1))
  35
  36 #define WDT_MODE                0x04
  37 #define WDT_MODE_EN             (1 << 0)
  38 #define WDT_MODE_RST_EN         (1 << 1)
  39
  40 #define DRV_NAME                "sunxi-wdt"
  41 #define DRV_VERSION             "1.0"
  42
  43 static bool nowayout = WATCHDOG_NOWAYOUT;
  44 static unsigned int timeout = WDT_MAX_TIMEOUT;
  45
  46 struct sunxi_wdt_dev {
  47         struct watchdog_device wdt_dev;
  48         void __iomem *wdt_base;
  49 };
  50
  51 /*
  52  * wdt_timeout_map maps the watchdog timer interval value in seconds to
  53  * the value of the register WDT_MODE bit 3:6
  54  *
  55  * [timeout seconds] = register value
  56  *
  57  */
  58
  59 static const int wdt_timeout_map[] = {
  60         [1] = 0b0001,  /* 1s  */
  61         [2] = 0b0010,  /* 2s  */
  62         [3] = 0b0011,  /* 3s  */
  63         [4] = 0b0100,  /* 4s  */
  64         [5] = 0b0101,  /* 5s  */
  65         [6] = 0b0110,  /* 6s  */
  66         [8] = 0b0111,  /* 8s  */
  67         [10] = 0b1000, /* 10s */
  68         [12] = 0b1001, /* 12s */
  69         [14] = 0b1010, /* 14s */
  70         [16] = 0b1011, /* 16s */
  71 };
  72
  73 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev)
  74 {
  75         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
  76         void __iomem *wdt_base = sunxi_wdt->wdt_base;
  77
  78         iowrite32(WDT_CTRL_RELOAD, wdt_base + WDT_CTRL);
  79
  80         return 0;
  81 }
  82
  83 static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev,
  84                 unsigned int timeout)
  85 {
  86         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
  87         void __iomem *wdt_base = sunxi_wdt->wdt_base;
  88         u32 reg;
  89
  90         if (wdt_timeout_map[timeout] == 0)
  91                 timeout++;
  92
  93         sunxi_wdt->wdt_dev.timeout = timeout;
  94
  95         reg = ioread32(wdt_base + WDT_MODE);
  96         reg &= ~WDT_TIMEOUT_MASK;
  97         reg |= WDT_MODE_TIMEOUT(wdt_timeout_map[timeout]);
  98         iowrite32(reg, wdt_base + WDT_MODE);
  99
 100         sunxi_wdt_ping(wdt_dev);
 101
 102         return 0;
 103 }
 104
 105 static int sunxi_wdt_stop(struct watchdog_device *wdt_dev)
 106 {
 107         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 108         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 109
 110         iowrite32(0, wdt_base + WDT_MODE);
 111
 112         return 0;
 113 }
 114
 115 static int sunxi_wdt_start(struct watchdog_device *wdt_dev)
 116 {
 117         u32 reg;
 118         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 119         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 120         int ret;
 121
 122         ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev,
 123                         sunxi_wdt->wdt_dev.timeout);
 124         if (ret < 0)
 125                 return ret;
 126
 127         reg = ioread32(wdt_base + WDT_MODE);
 128         reg |= (WDT_MODE_RST_EN | WDT_MODE_EN);
 129         iowrite32(reg, wdt_base + WDT_MODE);
 130
 131         return 0;
 132 }
 133
 134 static const struct watchdog_info sunxi_wdt_info = {
 135         .identity       = DRV_NAME,
 136         .options        = WDIOF_SETTIMEOUT |
 137                           WDIOF_KEEPALIVEPING |
 138                           WDIOF_MAGICCLOSE,
 139 };
 140
 141 static const struct watchdog_ops sunxi_wdt_ops = {
 142         .owner          = THIS_MODULE,
 143         .start          = sunxi_wdt_start,
 144         .stop           = sunxi_wdt_stop,
 145         .ping           = sunxi_wdt_ping,
 146         .set_timeout    = sunxi_wdt_set_timeout,
 147 };
 148
 149 static int __init sunxi_wdt_probe(struct platform_device *pdev)
 150 {
 151         struct sunxi_wdt_dev *sunxi_wdt;
 152         struct resource *res;
 153         int err;
 154
 155         sunxi_wdt = devm_kzalloc(&pdev->dev, sizeof(*sunxi_wdt), GFP_KERNEL);
 156         if (!sunxi_wdt)
 157                 return -EINVAL;
 158
 159         platform_set_drvdata(pdev, sunxi_wdt);
 160
 161         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 162         sunxi_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
 163         if (IS_ERR(sunxi_wdt->wdt_base))
 164                 return PTR_ERR(sunxi_wdt->wdt_base);
 165
 166         sunxi_wdt->wdt_dev.info = &sunxi_wdt_info;
 167         sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops;
 168         sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
 169         sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
 170         sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
 171         sunxi_wdt->wdt_dev.parent = &pdev->dev;
 172
 173         watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, &pdev->dev);
 174         watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout);
 175
 176         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt);
 177
 178         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
 179
 180         err = watchdog_register_device(&sunxi_wdt->wdt_dev);
 181         if (unlikely(err))
 182                 return err;
 183
 184         dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
 185                         sunxi_wdt->wdt_dev.timeout, nowayout);
 186
 187         return 0;
 188 }
 189
 190 static int __exit sunxi_wdt_remove(struct platform_device *pdev)
 191 {
 192         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
 193
 194         watchdog_unregister_device(&sunxi_wdt->wdt_dev);
 195         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, NULL);
 196
 197         return 0;
 198 }
 199
 200 static void sunxi_wdt_shutdown(struct platform_device *pdev)
 201 {
 202         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
 203
 204         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
 205 }
 206
 207 static const struct of_device_id sunxi_wdt_dt_ids[] = {
 208         { .compatible = "allwinner,sun4i-wdt" },
 209         { /* sentinel */ }
 210 };
 211 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
 212
 213 static struct platform_driver sunxi_wdt_driver = {
 214         .probe          = sunxi_wdt_probe,
 215         .remove         = sunxi_wdt_remove,
 216         .shutdown       = sunxi_wdt_shutdown,
 217         .driver         = {
 218                 .owner          = THIS_MODULE,
 219                 .name           = DRV_NAME,
 220                 .of_match_table = of_match_ptr(sunxi_wdt_dt_ids)
 221         },
 222 };
 223
 224 module_platform_driver(sunxi_wdt_driver);
 225
 226 module_param(timeout, uint, 0);
 227 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
 228
 229 module_param(nowayout, bool, 0);
 230 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
 231                 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 232
 233 MODULE_LICENSE("GPL");
 234 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
 235 MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
 236 MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
 237 MODULE_VERSION(DRV_VERSION);