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/of_device.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/types.h>
  28 #include <linux/watchdog.h>
  29
  30 #define WDT_MAX_TIMEOUT         16
  31 #define WDT_MIN_TIMEOUT         1
  32 #define WDT_TIMEOUT_MASK        0x0F
  33
  34 #define WDT_CTRL_RELOAD         ((1 << 0) | (0x0a57 << 1))
  35
  36 #define WDT_MODE_EN             (1 << 0)
  37
  38 #define DRV_NAME                "sunxi-wdt"
  39 #define DRV_VERSION             "1.0"
  40
  41 static bool nowayout = WATCHDOG_NOWAYOUT;
  42 static unsigned int timeout = WDT_MAX_TIMEOUT;
  43
  44 /*
  45  * This structure stores the register offsets for different variants
  46  * of Allwinner's watchdog hardware.
  47  */
  48 struct sunxi_wdt_reg {
  49         u8 wdt_ctrl;
  50         u8 wdt_cfg;
  51         u8 wdt_mode;
  52         u8 wdt_timeout_shift;
  53         u8 wdt_reset_mask;
  54         u8 wdt_reset_val;
  55 };
  56
  57 struct sunxi_wdt_dev {
  58         struct watchdog_device wdt_dev;
  59         void __iomem *wdt_base;
  60         const struct sunxi_wdt_reg *wdt_regs;
  61 };
  62
  63 /*
  64  * wdt_timeout_map maps the watchdog timer interval value in seconds to
  65  * the value of the register WDT_MODE at bits .wdt_timeout_shift ~ +3
  66  *
  67  * [timeout seconds] = register value
  68  *
  69  */
  70
  71 static const int wdt_timeout_map[] = {
  72         [1] = 0x1,  /* 1s  */
  73         [2] = 0x2,  /* 2s  */
  74         [3] = 0x3,  /* 3s  */
  75         [4] = 0x4,  /* 4s  */
  76         [5] = 0x5,  /* 5s  */
  77         [6] = 0x6,  /* 6s  */
  78         [8] = 0x7,  /* 8s  */
  79         [10] = 0x8, /* 10s */
  80         [12] = 0x9, /* 12s */
  81         [14] = 0xA, /* 14s */
  82         [16] = 0xB, /* 16s */
  83 };
  84
  85
  86 static int sunxi_wdt_restart(struct watchdog_device *wdt_dev,
  87                              unsigned long action, void *data)
  88 {
  89         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
  90         void __iomem *wdt_base = sunxi_wdt->wdt_base;
  91         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
  92         u32 val;
  93
  94         /* Set system reset function */
  95         val = readl(wdt_base + regs->wdt_cfg);
  96         val &= ~(regs->wdt_reset_mask);
  97         val |= regs->wdt_reset_val;
  98         writel(val, wdt_base + regs->wdt_cfg);
  99
 100         /* Set lowest timeout and enable watchdog */
 101         val = readl(wdt_base + regs->wdt_mode);
 102         val &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
 103         val |= WDT_MODE_EN;
 104         writel(val, wdt_base + regs->wdt_mode);
 105
 106         /*
 107          * Restart the watchdog. The default (and lowest) interval
 108          * value for the watchdog is 0.5s.
 109          */
 110         writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
 111
 112         while (1) {
 113                 mdelay(5);
 114                 val = readl(wdt_base + regs->wdt_mode);
 115                 val |= WDT_MODE_EN;
 116                 writel(val, wdt_base + regs->wdt_mode);
 117         }
 118         return 0;
 119 }
 120
 121 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev)
 122 {
 123         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 124         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 125         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
 126
 127         writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
 128
 129         return 0;
 130 }
 131
 132 static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev,
 133                 unsigned int timeout)
 134 {
 135         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 136         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 137         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
 138         u32 reg;
 139
 140         if (wdt_timeout_map[timeout] == 0)
 141                 timeout++;
 142
 143         sunxi_wdt->wdt_dev.timeout = timeout;
 144
 145         reg = readl(wdt_base + regs->wdt_mode);
 146         reg &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
 147         reg |= wdt_timeout_map[timeout] << regs->wdt_timeout_shift;
 148         writel(reg, wdt_base + regs->wdt_mode);
 149
 150         sunxi_wdt_ping(wdt_dev);
 151
 152         return 0;
 153 }
 154
 155 static int sunxi_wdt_stop(struct watchdog_device *wdt_dev)
 156 {
 157         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 158         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 159         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
 160
 161         writel(0, wdt_base + regs->wdt_mode);
 162
 163         return 0;
 164 }
 165
 166 static int sunxi_wdt_start(struct watchdog_device *wdt_dev)
 167 {
 168         u32 reg;
 169         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 170         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 171         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
 172         int ret;
 173
 174         ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev,
 175                         sunxi_wdt->wdt_dev.timeout);
 176         if (ret < 0)
 177                 return ret;
 178
 179         /* Set system reset function */
 180         reg = readl(wdt_base + regs->wdt_cfg);
 181         reg &= ~(regs->wdt_reset_mask);
 182         reg |= regs->wdt_reset_val;
 183         writel(reg, wdt_base + regs->wdt_cfg);
 184
 185         /* Enable watchdog */
 186         reg = readl(wdt_base + regs->wdt_mode);
 187         reg |= WDT_MODE_EN;
 188         writel(reg, wdt_base + regs->wdt_mode);
 189
 190         return 0;
 191 }
 192
 193 static const struct watchdog_info sunxi_wdt_info = {
 194         .identity       = DRV_NAME,
 195         .options        = WDIOF_SETTIMEOUT |
 196                           WDIOF_KEEPALIVEPING |
 197                           WDIOF_MAGICCLOSE,
 198 };
 199
 200 static const struct watchdog_ops sunxi_wdt_ops = {
 201         .owner          = THIS_MODULE,
 202         .start          = sunxi_wdt_start,
 203         .stop           = sunxi_wdt_stop,
 204         .ping           = sunxi_wdt_ping,
 205         .set_timeout    = sunxi_wdt_set_timeout,
 206         .restart        = sunxi_wdt_restart,
 207 };
 208
 209 static const struct sunxi_wdt_reg sun4i_wdt_reg = {
 210         .wdt_ctrl = 0x00,
 211         .wdt_cfg = 0x04,
 212         .wdt_mode = 0x04,
 213         .wdt_timeout_shift = 3,
 214         .wdt_reset_mask = 0x02,
 215         .wdt_reset_val = 0x02,
 216 };
 217
 218 static const struct sunxi_wdt_reg sun6i_wdt_reg = {
 219         .wdt_ctrl = 0x10,
 220         .wdt_cfg = 0x14,
 221         .wdt_mode = 0x18,
 222         .wdt_timeout_shift = 4,
 223         .wdt_reset_mask = 0x03,
 224         .wdt_reset_val = 0x01,
 225 };
 226
 227 static const struct of_device_id sunxi_wdt_dt_ids[] = {
 228         { .compatible = "allwinner,sun4i-a10-wdt", .data = &sun4i_wdt_reg },
 229         { .compatible = "allwinner,sun6i-a31-wdt", .data = &sun6i_wdt_reg },
 230         { /* sentinel */ }
 231 };
 232 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
 233
 234 static int sunxi_wdt_probe(struct platform_device *pdev)
 235 {
 236         struct sunxi_wdt_dev *sunxi_wdt;
 237         const struct of_device_id *device;
 238         struct resource *res;
 239         int err;
 240
 241         sunxi_wdt = devm_kzalloc(&pdev->dev, sizeof(*sunxi_wdt), GFP_KERNEL);
 242         if (!sunxi_wdt)
 243                 return -EINVAL;
 244
 245         platform_set_drvdata(pdev, sunxi_wdt);
 246
 247         device = of_match_device(sunxi_wdt_dt_ids, &pdev->dev);
 248         if (!device)
 249                 return -ENODEV;
 250
 251         sunxi_wdt->wdt_regs = device->data;
 252
 253         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 254         sunxi_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
 255         if (IS_ERR(sunxi_wdt->wdt_base))
 256                 return PTR_ERR(sunxi_wdt->wdt_base);
 257
 258         sunxi_wdt->wdt_dev.info = &sunxi_wdt_info;
 259         sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops;
 260         sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
 261         sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
 262         sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
 263         sunxi_wdt->wdt_dev.parent = &pdev->dev;
 264
 265         watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, &pdev->dev);
 266         watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout);
 267         watchdog_set_restart_priority(&sunxi_wdt->wdt_dev, 128);
 268
 269         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt);
 270
 271         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
 272
 273         err = watchdog_register_device(&sunxi_wdt->wdt_dev);
 274         if (unlikely(err))
 275                 return err;
 276
 277         dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
 278                         sunxi_wdt->wdt_dev.timeout, nowayout);
 279
 280         return 0;
 281 }
 282
 283 static int sunxi_wdt_remove(struct platform_device *pdev)
 284 {
 285         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
 286
 287         watchdog_unregister_device(&sunxi_wdt->wdt_dev);
 288         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, NULL);
 289
 290         return 0;
 291 }
 292
 293 static void sunxi_wdt_shutdown(struct platform_device *pdev)
 294 {
 295         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
 296
 297         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
 298 }
 299
 300 static struct platform_driver sunxi_wdt_driver = {
 301         .probe          = sunxi_wdt_probe,
 302         .remove         = sunxi_wdt_remove,
 303         .shutdown       = sunxi_wdt_shutdown,
 304         .driver         = {
 305                 .name           = DRV_NAME,
 306                 .of_match_table = sunxi_wdt_dt_ids,
 307         },
 308 };
 309
 310 module_platform_driver(sunxi_wdt_driver);
 311
 312 module_param(timeout, uint, 0);
 313 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
 314
 315 module_param(nowayout, bool, 0);
 316 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
 317                 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 318
 319 MODULE_LICENSE("GPL");
 320 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
 321 MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
 322 MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
 323 MODULE_VERSION(DRV_VERSION);