drivers/watchdog/bcm63xx_wdt.c

   1 /*
   2  *  Broadcom BCM63xx SoC watchdog driver
   3  *
   4  *  Copyright (C) 2007, Miguel Gaio <miguel.gaio@efixo.com>
   5  *  Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
   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
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/bitops.h>
  16 #include <linux/errno.h>
  17 #include <linux/fs.h>
  18 #include <linux/io.h>
  19 #include <linux/kernel.h>
  20 #include <linux/miscdevice.h>
  21 #include <linux/module.h>
  22 #include <linux/moduleparam.h>
  23 #include <linux/types.h>
  24 #include <linux/uaccess.h>
  25 #include <linux/watchdog.h>
  26 #include <linux/timer.h>
  27 #include <linux/jiffies.h>
  28 #include <linux/interrupt.h>
  29 #include <linux/ptrace.h>
  30 #include <linux/resource.h>
  31 #include <linux/platform_device.h>
  32
  33 #include <bcm63xx_cpu.h>
  34 #include <bcm63xx_io.h>
  35 #include <bcm63xx_regs.h>
  36 #include <bcm63xx_timer.h>
  37
  38 #define PFX KBUILD_MODNAME
  39
  40 #define WDT_HZ          50000000 /* Fclk */
  41 #define WDT_DEFAULT_TIME        30      /* seconds */
  42 #define WDT_MAX_TIME            256     /* seconds */
  43
  44 static struct {
  45         void __iomem *regs;
  46         struct timer_list timer;
  47         unsigned long inuse;
  48         atomic_t ticks;
  49 } bcm63xx_wdt_device;
  50
  51 static int expect_close;
  52
  53 static int wdt_time = WDT_DEFAULT_TIME;
  54 static bool nowayout = WATCHDOG_NOWAYOUT;
  55 module_param(nowayout, bool, 0);
  56 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  57         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  58
  59 /* HW functions */
  60 static void bcm63xx_wdt_hw_start(void)
  61 {
  62         bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
  63         bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  64         bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  65 }
  66
  67 static void bcm63xx_wdt_hw_stop(void)
  68 {
  69         bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  70         bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  71 }
  72
  73 static void bcm63xx_wdt_isr(void *data)
  74 {
  75         struct pt_regs *regs = get_irq_regs();
  76
  77         die(PFX " fire", regs);
  78 }
  79
  80 static void bcm63xx_timer_tick(unsigned long unused)
  81 {
  82         if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
  83                 bcm63xx_wdt_hw_start();
  84                 mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
  85         } else
  86                 pr_crit("watchdog will restart system\n");
  87 }
  88
  89 static void bcm63xx_wdt_pet(void)
  90 {
  91         atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
  92 }
  93
  94 static void bcm63xx_wdt_start(void)
  95 {
  96         bcm63xx_wdt_pet();
  97         bcm63xx_timer_tick(0);
  98 }
  99
 100 static void bcm63xx_wdt_pause(void)
 101 {
 102         del_timer_sync(&bcm63xx_wdt_device.timer);
 103         bcm63xx_wdt_hw_stop();
 104 }
 105
 106 static int bcm63xx_wdt_settimeout(int new_time)
 107 {
 108         if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
 109                 return -EINVAL;
 110
 111         wdt_time = new_time;
 112
 113         return 0;
 114 }
 115
 116 static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
 117 {
 118         if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
 119                 return -EBUSY;
 120
 121         bcm63xx_wdt_start();
 122         return nonseekable_open(inode, file);
 123 }
 124
 125 static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
 126 {
 127         if (expect_close == 42)
 128                 bcm63xx_wdt_pause();
 129         else {
 130                 pr_crit("Unexpected close, not stopping watchdog!\n");
 131                 bcm63xx_wdt_start();
 132         }
 133         clear_bit(0, &bcm63xx_wdt_device.inuse);
 134         expect_close = 0;
 135         return 0;
 136 }
 137
 138 static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
 139                                 size_t len, loff_t *ppos)
 140 {
 141         if (len) {
 142                 if (!nowayout) {
 143                         size_t i;
 144
 145                         /* In case it was set long ago */
 146                         expect_close = 0;
 147
 148                         for (i = 0; i != len; i++) {
 149                                 char c;
 150                                 if (get_user(c, data + i))
 151                                         return -EFAULT;
 152                                 if (c == 'V')
 153                                         expect_close = 42;
 154                         }
 155                 }
 156                 bcm63xx_wdt_pet();
 157         }
 158         return len;
 159 }
 160
 161 static struct watchdog_info bcm63xx_wdt_info = {
 162         .identity       = PFX,
 163         .options        = WDIOF_SETTIMEOUT |
 164                                 WDIOF_KEEPALIVEPING |
 165                                 WDIOF_MAGICCLOSE,
 166 };
 167
 168
 169 static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
 170                                 unsigned long arg)
 171 {
 172         void __user *argp = (void __user *)arg;
 173         int __user *p = argp;
 174         int new_value, retval = -EINVAL;
 175
 176         switch (cmd) {
 177         case WDIOC_GETSUPPORT:
 178                 return copy_to_user(argp, &bcm63xx_wdt_info,
 179                         sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
 180
 181         case WDIOC_GETSTATUS:
 182         case WDIOC_GETBOOTSTATUS:
 183                 return put_user(0, p);
 184
 185         case WDIOC_SETOPTIONS:
 186                 if (get_user(new_value, p))
 187                         return -EFAULT;
 188
 189                 if (new_value & WDIOS_DISABLECARD) {
 190                         bcm63xx_wdt_pause();
 191                         retval = 0;
 192                 }
 193                 if (new_value & WDIOS_ENABLECARD) {
 194                         bcm63xx_wdt_start();
 195                         retval = 0;
 196                 }
 197
 198                 return retval;
 199
 200         case WDIOC_KEEPALIVE:
 201                 bcm63xx_wdt_pet();
 202                 return 0;
 203
 204         case WDIOC_SETTIMEOUT:
 205                 if (get_user(new_value, p))
 206                         return -EFAULT;
 207
 208                 if (bcm63xx_wdt_settimeout(new_value))
 209                         return -EINVAL;
 210
 211                 bcm63xx_wdt_pet();
 212
 213         case WDIOC_GETTIMEOUT:
 214                 return put_user(wdt_time, p);
 215
 216         default:
 217                 return -ENOTTY;
 218
 219         }
 220 }
 221
 222 static const struct file_operations bcm63xx_wdt_fops = {
 223         .owner          = THIS_MODULE,
 224         .llseek         = no_llseek,
 225         .write          = bcm63xx_wdt_write,
 226         .unlocked_ioctl = bcm63xx_wdt_ioctl,
 227         .open           = bcm63xx_wdt_open,
 228         .release        = bcm63xx_wdt_release,
 229 };
 230
 231 static struct miscdevice bcm63xx_wdt_miscdev = {
 232         .minor  = WATCHDOG_MINOR,
 233         .name   = "watchdog",
 234         .fops   = &bcm63xx_wdt_fops,
 235 };
 236
 237
 238 static int bcm63xx_wdt_probe(struct platform_device *pdev)
 239 {
 240         int ret;
 241         struct resource *r;
 242
 243         setup_timer(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0L);
 244
 245         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 246         if (!r) {
 247                 dev_err(&pdev->dev, "failed to get resources\n");
 248                 return -ENODEV;
 249         }
 250
 251         bcm63xx_wdt_device.regs = devm_ioremap_nocache(&pdev->dev, r->start,
 252                                                         resource_size(r));
 253         if (!bcm63xx_wdt_device.regs) {
 254                 dev_err(&pdev->dev, "failed to remap I/O resources\n");
 255                 return -ENXIO;
 256         }
 257
 258         ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL);
 259         if (ret < 0) {
 260                 dev_err(&pdev->dev, "failed to register wdt timer isr\n");
 261                 return ret;
 262         }
 263
 264         if (bcm63xx_wdt_settimeout(wdt_time)) {
 265                 bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
 266                 dev_info(&pdev->dev,
 267                         ": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
 268                         wdt_time);
 269         }
 270
 271         ret = misc_register(&bcm63xx_wdt_miscdev);
 272         if (ret < 0) {
 273                 dev_err(&pdev->dev, "failed to register watchdog device\n");
 274                 goto unregister_timer;
 275         }
 276
 277         dev_info(&pdev->dev, " started, timer margin: %d sec\n",
 278                                                 WDT_DEFAULT_TIME);
 279
 280         return 0;
 281
 282 unregister_timer:
 283         bcm63xx_timer_unregister(TIMER_WDT_ID);
 284         return ret;
 285 }
 286
 287 static int bcm63xx_wdt_remove(struct platform_device *pdev)
 288 {
 289         if (!nowayout)
 290                 bcm63xx_wdt_pause();
 291
 292         misc_deregister(&bcm63xx_wdt_miscdev);
 293         bcm63xx_timer_unregister(TIMER_WDT_ID);
 294         return 0;
 295 }
 296
 297 static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
 298 {
 299         bcm63xx_wdt_pause();
 300 }
 301
 302 static struct platform_driver bcm63xx_wdt_driver = {
 303         .probe  = bcm63xx_wdt_probe,
 304         .remove = bcm63xx_wdt_remove,
 305         .shutdown = bcm63xx_wdt_shutdown,
 306         .driver = {
 307                 .name = "bcm63xx-wdt",
 308         }
 309 };
 310
 311 module_platform_driver(bcm63xx_wdt_driver);
 312
 313 MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
 314 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 315 MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
 316 MODULE_LICENSE("GPL");
 317 MODULE_ALIAS("platform:bcm63xx-wdt");