linux/drivers/watchdog/sunxi_wdt.c
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   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
  43static bool nowayout = WATCHDOG_NOWAYOUT;
  44static unsigned int timeout = WDT_MAX_TIMEOUT;
  45
  46struct 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
  59static 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
  73static 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
  83static 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
 105static 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
 115static 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
 134static const struct watchdog_info sunxi_wdt_info = {
 135        .identity       = DRV_NAME,
 136        .options        = WDIOF_SETTIMEOUT |
 137                          WDIOF_KEEPALIVEPING |
 138                          WDIOF_MAGICCLOSE,
 139};
 140
 141static 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
 149static int 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
 190static int 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
 200static 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
 207static const struct of_device_id sunxi_wdt_dt_ids[] = {
 208        { .compatible = "allwinner,sun4i-wdt" },
 209        { /* sentinel */ }
 210};
 211MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
 212
 213static 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
 224module_platform_driver(sunxi_wdt_driver);
 225
 226module_param(timeout, uint, 0);
 227MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
 228
 229module_param(nowayout, bool, 0);
 230MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
 231                "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 232
 233MODULE_LICENSE("GPL");
 234MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
 235MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
 236MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
 237MODULE_VERSION(DRV_VERSION);
 238
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