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 #include <linux/bitops.h>
  14 #include <linux/errno.h>
  15 #include <linux/fs.h>
  16 #include <linux/init.h>
  17 #include <linux/kernel.h>
  18 #include <linux/miscdevice.h>
  19 #include <linux/module.h>
  20 #include <linux/moduleparam.h>
  21 #include <linux/reboot.h>
  22 #include <linux/types.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/watchdog.h>
  25 #include <linux/timer.h>
  26 #include <linux/jiffies.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/ptrace.h>
  29 #include <linux/resource.h>
  30 #include <linux/platform_device.h>
  31
  32 #include <bcm63xx_cpu.h>
  33 #include <bcm63xx_io.h>
  34 #include <bcm63xx_regs.h>
  35 #include <bcm63xx_timer.h>
  36
  37 #define PFX KBUILD_MODNAME
  38
  39 #define WDT_HZ          50000000 /* Fclk */
  40 #define WDT_DEFAULT_TIME        30      /* seconds */
  41 #define WDT_MAX_TIME            256     /* seconds */
  42
  43 static struct {
  44         void __iomem *regs;
  45         struct timer_list timer;
  46         int default_ticks;
  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 int nowayout = WATCHDOG_NOWAYOUT;
  55 module_param(nowayout, int, 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                 printk(KERN_CRIT PFX ": 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                 printk(KERN_CRIT PFX
 131                         ": Unexpected close, not stopping watchdog!\n");
 132                 bcm63xx_wdt_start();
 133         }
 134         clear_bit(0, &bcm63xx_wdt_device.inuse);
 135         expect_close = 0;
 136         return 0;
 137 }
 138
 139 static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
 140                                 size_t len, loff_t *ppos)
 141 {
 142         if (len) {
 143                 if (!nowayout) {
 144                         size_t i;
 145
 146                         /* In case it was set long ago */
 147                         expect_close = 0;
 148
 149                         for (i = 0; i != len; i++) {
 150                                 char c;
 151                                 if (get_user(c, data + i))
 152                                         return -EFAULT;
 153                                 if (c == 'V')
 154                                         expect_close = 42;
 155                         }
 156                 }
 157                 bcm63xx_wdt_pet();
 158         }
 159         return len;
 160 }
 161
 162 static struct watchdog_info bcm63xx_wdt_info = {
 163         .identity       = PFX,
 164         .options        = WDIOF_SETTIMEOUT |
 165                                 WDIOF_KEEPALIVEPING |
 166                                 WDIOF_MAGICCLOSE,
 167 };
 168
 169
 170 static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
 171                                 unsigned long arg)
 172 {
 173         void __user *argp = (void __user *)arg;
 174         int __user *p = argp;
 175         int new_value, retval = -EINVAL;
 176
 177         switch (cmd) {
 178         case WDIOC_GETSUPPORT:
 179                 return copy_to_user(argp, &bcm63xx_wdt_info,
 180                         sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
 181
 182         case WDIOC_GETSTATUS:
 183         case WDIOC_GETBOOTSTATUS:
 184                 return put_user(0, p);
 185
 186         case WDIOC_SETOPTIONS:
 187                 if (get_user(new_value, p))
 188                         return -EFAULT;
 189
 190                 if (new_value & WDIOS_DISABLECARD) {
 191                         bcm63xx_wdt_pause();
 192                         retval = 0;
 193                 }
 194                 if (new_value & WDIOS_ENABLECARD) {
 195                         bcm63xx_wdt_start();
 196                         retval = 0;
 197                 }
 198
 199                 return retval;
 200
 201         case WDIOC_KEEPALIVE:
 202                 bcm63xx_wdt_pet();
 203                 return 0;
 204
 205         case WDIOC_SETTIMEOUT:
 206                 if (get_user(new_value, p))
 207                         return -EFAULT;
 208
 209                 if (bcm63xx_wdt_settimeout(new_value))
 210                         return -EINVAL;
 211
 212                 bcm63xx_wdt_pet();
 213
 214         case WDIOC_GETTIMEOUT:
 215                 return put_user(wdt_time, p);
 216
 217         default:
 218                 return -ENOTTY;
 219
 220         }
 221 }
 222
 223 static int bcm63xx_wdt_notify_sys(struct notifier_block *this,
 224                                 unsigned long code, void *unused)
 225 {
 226         if (code == SYS_DOWN || code == SYS_HALT)
 227                 bcm63xx_wdt_pause();
 228         return NOTIFY_DONE;
 229 }
 230
 231 static const struct file_operations bcm63xx_wdt_fops = {
 232         .owner          = THIS_MODULE,
 233         .llseek         = no_llseek,
 234         .write          = bcm63xx_wdt_write,
 235         .unlocked_ioctl = bcm63xx_wdt_ioctl,
 236         .open           = bcm63xx_wdt_open,
 237         .release        = bcm63xx_wdt_release,
 238 };
 239
 240 static struct miscdevice bcm63xx_wdt_miscdev = {
 241         .minor  = WATCHDOG_MINOR,
 242         .name   = "watchdog",
 243         .fops   = &bcm63xx_wdt_fops,
 244 };
 245
 246 static struct notifier_block bcm63xx_wdt_notifier = {
 247         .notifier_call = bcm63xx_wdt_notify_sys,
 248 };
 249
 250
 251 static int bcm63xx_wdt_probe(struct platform_device *pdev)
 252 {
 253         int ret;
 254         struct resource *r;
 255
 256         setup_timer(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0L);
 257
 258         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 259         if (!r) {
 260                 dev_err(&pdev->dev, "failed to get resources\n");
 261                 return -ENODEV;
 262         }
 263
 264         bcm63xx_wdt_device.regs = ioremap_nocache(r->start, r->end - r->start);
 265         if (!bcm63xx_wdt_device.regs) {
 266                 dev_err(&pdev->dev, "failed to remap I/O resources\n");
 267                 return -ENXIO;
 268         }
 269
 270         ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL);
 271         if (ret < 0) {
 272                 dev_err(&pdev->dev, "failed to register wdt timer isr\n");
 273                 goto unmap;
 274         }
 275
 276         if (bcm63xx_wdt_settimeout(wdt_time)) {
 277                 bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
 278                 dev_info(&pdev->dev,
 279                         ": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
 280                         wdt_time);
 281         }
 282
 283         ret = register_reboot_notifier(&bcm63xx_wdt_notifier);
 284         if (ret) {
 285                 dev_err(&pdev->dev, "failed to register reboot_notifier\n");
 286                 goto unregister_timer;
 287         }
 288
 289         ret = misc_register(&bcm63xx_wdt_miscdev);
 290         if (ret < 0) {
 291                 dev_err(&pdev->dev, "failed to register watchdog device\n");
 292                 goto unregister_reboot_notifier;
 293         }
 294
 295         dev_info(&pdev->dev, " started, timer margin: %d sec\n",
 296                                                 WDT_DEFAULT_TIME);
 297
 298         return 0;
 299
 300 unregister_reboot_notifier:
 301         unregister_reboot_notifier(&bcm63xx_wdt_notifier);
 302 unregister_timer:
 303         bcm63xx_timer_unregister(TIMER_WDT_ID);
 304 unmap:
 305         iounmap(bcm63xx_wdt_device.regs);
 306         return ret;
 307 }
 308
 309 static int bcm63xx_wdt_remove(struct platform_device *pdev)
 310 {
 311         if (!nowayout)
 312                 bcm63xx_wdt_pause();
 313
 314         misc_deregister(&bcm63xx_wdt_miscdev);
 315
 316         iounmap(bcm63xx_wdt_device.regs);
 317
 318         unregister_reboot_notifier(&bcm63xx_wdt_notifier);
 319         bcm63xx_timer_unregister(TIMER_WDT_ID);
 320
 321         return 0;
 322 }
 323
 324 static struct platform_driver bcm63xx_wdt = {
 325         .probe  = bcm63xx_wdt_probe,
 326         .remove = bcm63xx_wdt_remove,
 327         .driver = {
 328                 .name = "bcm63xx-wdt",
 329         }
 330 };
 331
 332 static int __init bcm63xx_wdt_init(void)
 333 {
 334         return platform_driver_register(&bcm63xx_wdt);
 335 }
 336
 337 static void __exit bcm63xx_wdt_exit(void)
 338 {
 339         platform_driver_unregister(&bcm63xx_wdt);
 340 }
 341
 342 module_init(bcm63xx_wdt_init);
 343 module_exit(bcm63xx_wdt_exit);
 344
 345 MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
 346 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 347 MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
 348 MODULE_LICENSE("GPL");
 349 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 350 MODULE_ALIAS("platform:bcm63xx-wdt");