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/notifier.h>
  25 #include <linux/of.h>
  26 #include <linux/of_device.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/reboot.h>
  29 #include <linux/types.h>
  30 #include <linux/watchdog.h>
  31
  32 #define WDT_MAX_TIMEOUT         16
  33 #define WDT_MIN_TIMEOUT         1
  34 #define WDT_TIMEOUT_MASK        0x0F
  35
  36 #define WDT_CTRL_RELOAD         ((1 << 0) | (0x0a57 << 1))
  37
  38 #define WDT_MODE_EN             (1 << 0)
  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 /*
  47  * This structure stores the register offsets for different variants
  48  * of Allwinner's watchdog hardware.
  49  */
  50 struct sunxi_wdt_reg {
  51         u8 wdt_ctrl;
  52         u8 wdt_cfg;
  53         u8 wdt_mode;
  54         u8 wdt_timeout_shift;
  55         u8 wdt_reset_mask;
  56         u8 wdt_reset_val;
  57 };
  58
  59 struct sunxi_wdt_dev {
  60         struct watchdog_device wdt_dev;
  61         void __iomem *wdt_base;
  62         const struct sunxi_wdt_reg *wdt_regs;
  63         struct notifier_block restart_handler;
  64 };
  65
  66 /*
  67  * wdt_timeout_map maps the watchdog timer interval value in seconds to
  68  * the value of the register WDT_MODE at bits .wdt_timeout_shift ~ +3
  69  *
  70  * [timeout seconds] = register value
  71  *
  72  */
  73
  74 static const int wdt_timeout_map[] = {
  75         [1] = 0x1,  /* 1s  */
  76         [2] = 0x2,  /* 2s  */
  77         [3] = 0x3,  /* 3s  */
  78         [4] = 0x4,  /* 4s  */
  79         [5] = 0x5,  /* 5s  */
  80         [6] = 0x6,  /* 6s  */
  81         [8] = 0x7,  /* 8s  */
  82         [10] = 0x8, /* 10s */
  83         [12] = 0x9, /* 12s */
  84         [14] = 0xA, /* 14s */
  85         [16] = 0xB, /* 16s */
  86 };
  87
  88
  89 static int sunxi_restart_handle(struct notifier_block *this, unsigned long mode,
  90                                 void *cmd)
  91 {
  92         struct sunxi_wdt_dev *sunxi_wdt = container_of(this,
  93                                                        struct sunxi_wdt_dev,
  94                                                        restart_handler);
  95         void __iomem *wdt_base = sunxi_wdt->wdt_base;
  96         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
  97         u32 val;
  98
  99         /* Set system reset function */
 100         val = readl(wdt_base + regs->wdt_cfg);
 101         val &= ~(regs->wdt_reset_mask);
 102         val |= regs->wdt_reset_val;
 103         writel(val, wdt_base + regs->wdt_cfg);
 104
 105         /* Set lowest timeout and enable watchdog */
 106         val = readl(wdt_base + regs->wdt_mode);
 107         val &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
 108         val |= WDT_MODE_EN;
 109         writel(val, wdt_base + regs->wdt_mode);
 110
 111         /*
 112          * Restart the watchdog. The default (and lowest) interval
 113          * value for the watchdog is 0.5s.
 114          */
 115         writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
 116
 117         while (1) {
 118                 mdelay(5);
 119                 val = readl(wdt_base + regs->wdt_mode);
 120                 val |= WDT_MODE_EN;
 121                 writel(val, wdt_base + regs->wdt_mode);
 122         }
 123         return NOTIFY_DONE;
 124 }
 125
 126 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev)
 127 {
 128         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 129         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 130         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
 131
 132         writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
 133
 134         return 0;
 135 }
 136
 137 static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev,
 138                 unsigned int timeout)
 139 {
 140         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 141         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 142         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
 143         u32 reg;
 144
 145         if (wdt_timeout_map[timeout] == 0)
 146                 timeout++;
 147
 148         sunxi_wdt->wdt_dev.timeout = timeout;
 149
 150         reg = readl(wdt_base + regs->wdt_mode);
 151         reg &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
 152         reg |= wdt_timeout_map[timeout] << regs->wdt_timeout_shift;
 153         writel(reg, wdt_base + regs->wdt_mode);
 154
 155         sunxi_wdt_ping(wdt_dev);
 156
 157         return 0;
 158 }
 159
 160 static int sunxi_wdt_stop(struct watchdog_device *wdt_dev)
 161 {
 162         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 163         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 164         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
 165
 166         writel(0, wdt_base + regs->wdt_mode);
 167
 168         return 0;
 169 }
 170
 171 static int sunxi_wdt_start(struct watchdog_device *wdt_dev)
 172 {
 173         u32 reg;
 174         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 175         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 176         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
 177         int ret;
 178
 179         ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev,
 180                         sunxi_wdt->wdt_dev.timeout);
 181         if (ret < 0)
 182                 return ret;
 183
 184         /* Set system reset function */
 185         reg = readl(wdt_base + regs->wdt_cfg);
 186         reg &= ~(regs->wdt_reset_mask);
 187         reg |= regs->wdt_reset_val;
 188         writel(reg, wdt_base + regs->wdt_cfg);
 189
 190         /* Enable watchdog */
 191         reg = readl(wdt_base + regs->wdt_mode);
 192         reg |= WDT_MODE_EN;
 193         writel(reg, wdt_base + regs->wdt_mode);
 194
 195         return 0;
 196 }
 197
 198 static const struct watchdog_info sunxi_wdt_info = {
 199         .identity       = DRV_NAME,
 200         .options        = WDIOF_SETTIMEOUT |
 201                           WDIOF_KEEPALIVEPING |
 202                           WDIOF_MAGICCLOSE,
 203 };
 204
 205 static const struct watchdog_ops sunxi_wdt_ops = {
 206         .owner          = THIS_MODULE,
 207         .start          = sunxi_wdt_start,
 208         .stop           = sunxi_wdt_stop,
 209         .ping           = sunxi_wdt_ping,
 210         .set_timeout    = sunxi_wdt_set_timeout,
 211 };
 212
 213 static const struct sunxi_wdt_reg sun4i_wdt_reg = {
 214         .wdt_ctrl = 0x00,
 215         .wdt_cfg = 0x04,
 216         .wdt_mode = 0x04,
 217         .wdt_timeout_shift = 3,
 218         .wdt_reset_mask = 0x02,
 219         .wdt_reset_val = 0x02,
 220 };
 221
 222 static const struct sunxi_wdt_reg sun6i_wdt_reg = {
 223         .wdt_ctrl = 0x10,
 224         .wdt_cfg = 0x14,
 225         .wdt_mode = 0x18,
 226         .wdt_timeout_shift = 4,
 227         .wdt_reset_mask = 0x03,
 228         .wdt_reset_val = 0x01,
 229 };
 230
 231 static const struct of_device_id sunxi_wdt_dt_ids[] = {
 232         { .compatible = "allwinner,sun4i-a10-wdt", .data = &sun4i_wdt_reg },
 233         { .compatible = "allwinner,sun6i-a31-wdt", .data = &sun6i_wdt_reg },
 234         { /* sentinel */ }
 235 };
 236 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
 237
 238 static int sunxi_wdt_probe(struct platform_device *pdev)
 239 {
 240         struct sunxi_wdt_dev *sunxi_wdt;
 241         const struct of_device_id *device;
 242         struct resource *res;
 243         int err;
 244
 245         sunxi_wdt = devm_kzalloc(&pdev->dev, sizeof(*sunxi_wdt), GFP_KERNEL);
 246         if (!sunxi_wdt)
 247                 return -EINVAL;
 248
 249         platform_set_drvdata(pdev, sunxi_wdt);
 250
 251         device = of_match_device(sunxi_wdt_dt_ids, &pdev->dev);
 252         if (!device)
 253                 return -ENODEV;
 254
 255         sunxi_wdt->wdt_regs = device->data;
 256
 257         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 258         sunxi_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
 259         if (IS_ERR(sunxi_wdt->wdt_base))
 260                 return PTR_ERR(sunxi_wdt->wdt_base);
 261
 262         sunxi_wdt->wdt_dev.info = &sunxi_wdt_info;
 263         sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops;
 264         sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
 265         sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
 266         sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
 267         sunxi_wdt->wdt_dev.parent = &pdev->dev;
 268
 269         watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, &pdev->dev);
 270         watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout);
 271
 272         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt);
 273
 274         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
 275
 276         err = watchdog_register_device(&sunxi_wdt->wdt_dev);
 277         if (unlikely(err))
 278                 return err;
 279
 280         sunxi_wdt->restart_handler.notifier_call = sunxi_restart_handle;
 281         sunxi_wdt->restart_handler.priority = 128;
 282         err = register_restart_handler(&sunxi_wdt->restart_handler);
 283         if (err)
 284                 dev_err(&pdev->dev,
 285                         "cannot register restart handler (err=%d)\n", err);
 286
 287         dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
 288                         sunxi_wdt->wdt_dev.timeout, nowayout);
 289
 290         return 0;
 291 }
 292
 293 static int sunxi_wdt_remove(struct platform_device *pdev)
 294 {
 295         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
 296
 297         unregister_restart_handler(&sunxi_wdt->restart_handler);
 298
 299         watchdog_unregister_device(&sunxi_wdt->wdt_dev);
 300         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, NULL);
 301
 302         return 0;
 303 }
 304
 305 static void sunxi_wdt_shutdown(struct platform_device *pdev)
 306 {
 307         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
 308
 309         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
 310 }
 311
 312 static struct platform_driver sunxi_wdt_driver = {
 313         .probe          = sunxi_wdt_probe,
 314         .remove         = sunxi_wdt_remove,
 315         .shutdown       = sunxi_wdt_shutdown,
 316         .driver         = {
 317                 .name           = DRV_NAME,
 318                 .of_match_table = sunxi_wdt_dt_ids,
 319         },
 320 };
 321
 322 module_platform_driver(sunxi_wdt_driver);
 323
 324 module_param(timeout, uint, 0);
 325 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
 326
 327 module_param(nowayout, bool, 0);
 328 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
 329                 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 330
 331 MODULE_LICENSE("GPL");
 332 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
 333 MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
 334 MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
 335 MODULE_VERSION(DRV_VERSION);