target/linux/brcm63xx/files/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/resource.h>
  28 #include <linux/platform_device.h>
  29
  30 #include <bcm63xx_cpu.h>
  31 #include <bcm63xx_io.h>
  32 #include <bcm63xx_regs.h>
  33
  34 #define PFX KBUILD_MODNAME
  35
  36 #define WDT_HZ          50000000 /* Fclk */
  37 #define WDT_DEFAULT_TIME        30      /* seconds */
  38 #define WDT_MAX_TIME            256     /* seconds */
  39
  40 static struct {
  41         void __iomem *regs;
  42         struct timer_list timer;
  43         int default_ticks;
  44         unsigned long inuse;
  45         atomic_t ticks;
  46 } bcm63xx_wdt_device;
  47
  48 static int expect_close;
  49 static int timeout;
  50
  51 static int wdt_time = WDT_DEFAULT_TIME;
  52 static int nowayout = WATCHDOG_NOWAYOUT;
  53 module_param(nowayout, int, 0);
  54 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  55         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  56
  57 /* HW functions */
  58 static void bcm63xx_wdt_hw_start(void)
  59 {
  60         bcm_writel(0xffffffff, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
  61         bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  62         bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  63 }
  64
  65 static void bcm63xx_wdt_hw_stop(void)
  66 {
  67         bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  68         bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  69 }
  70
  71 static void bcm63xx_timer_tick(unsigned long unused)
  72 {
  73         if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
  74                 bcm63xx_wdt_hw_start();
  75                 mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
  76         } else
  77                 printk(KERN_CRIT PFX "watchdog will restart system\n");
  78 }
  79
  80 static void bcm63xx_wdt_pet(void)
  81 {
  82         atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
  83 }
  84
  85 static void bcm63xx_wdt_start(void)
  86 {
  87         bcm63xx_wdt_pet();
  88         bcm63xx_timer_tick(0);
  89 }
  90
  91 static void bcm63xx_wdt_pause(void)
  92 {
  93         del_timer_sync(&bcm63xx_wdt_device.timer);
  94         bcm63xx_wdt_hw_stop();
  95 }
  96
  97 static int bcm63xx_wdt_settimeout(int new_time)
  98 {
  99         if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
 100                 return -EINVAL;
 101
 102         wdt_time = new_time;
 103
 104         return 0;
 105 }
 106
 107 static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
 108 {
 109         if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
 110                 return -EBUSY;
 111
 112         bcm63xx_wdt_start();
 113         return nonseekable_open(inode, file);
 114 }
 115
 116 static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
 117 {
 118         if (expect_close == 42)
 119                 bcm63xx_wdt_pause();
 120         else {
 121                 printk(KERN_CRIT PFX
 122                         ": Unexpected close, not stopping watchdog!\n");
 123                 bcm63xx_wdt_start();
 124         }
 125         clear_bit(0, &bcm63xx_wdt_device.inuse);
 126         expect_close = 0;
 127         return 0;
 128 }
 129
 130 static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
 131                                 size_t len, loff_t *ppos)
 132 {
 133         if (len) {
 134                 if (!nowayout) {
 135                         size_t i;
 136
 137                         /* In case it was set long ago */
 138                         expect_close = 0;
 139
 140                         for (i = 0; i != len; i++) {
 141                                 char c;
 142                                 if (get_user(c, data + i))
 143                                         return -EFAULT;
 144                                 if (c == 'V')
 145                                         expect_close = 42;
 146                         }
 147                 }
 148                 bcm63xx_wdt_pet();
 149         }
 150         return len;
 151 }
 152
 153 static struct watchdog_info bcm63xx_wdt_info = {
 154         .identity       = PFX,
 155         .options        = WDIOF_SETTIMEOUT |
 156                                 WDIOF_KEEPALIVEPING |
 157                                 WDIOF_MAGICCLOSE,
 158 };
 159
 160
 161 static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
 162                                 unsigned long arg)
 163 {
 164         void __user *argp = (void __user *)arg;
 165         int __user *p = argp;
 166         int new_value, retval = -EINVAL;
 167
 168         switch (cmd) {
 169         case WDIOC_GETSUPPORT:
 170                 return copy_to_user(argp, &bcm63xx_wdt_info,
 171                         sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
 172
 173         case WDIOC_GETSTATUS:
 174         case WDIOC_GETBOOTSTATUS:
 175                 return put_user(0, p);
 176
 177         case WDIOC_SETOPTIONS:
 178                 if (get_user(new_value, p))
 179                         return -EFAULT;
 180
 181                 if (new_value & WDIOS_DISABLECARD) {
 182                         bcm63xx_wdt_pause();
 183                         retval = 0;
 184                 }
 185                 if (new_value & WDIOS_ENABLECARD) {
 186                         bcm63xx_wdt_start();
 187                         retval = 0;
 188                 }
 189
 190                 return retval;
 191
 192         case WDIOC_KEEPALIVE:
 193                 bcm63xx_wdt_pet();
 194                 return 0;
 195
 196         case WDIOC_SETTIMEOUT:
 197                 if (get_user(new_value, p))
 198                         return -EFAULT;
 199
 200                 if (bcm63xx_wdt_settimeout(new_value))
 201                         return -EINVAL;
 202
 203                 bcm63xx_wdt_pet();
 204
 205         case WDIOC_GETTIMEOUT:
 206                 return put_user(wdt_time, p);
 207
 208         default:
 209                 return -ENOTTY;
 210
 211         }
 212 }
 213
 214 static int bcm63xx_wdt_notify_sys(struct notifier_block *this,
 215            unsigned long code, void *unused)
 216 {
 217         if (code == SYS_DOWN || code == SYS_HALT)
 218                 bcm63xx_wdt_pause();
 219         return NOTIFY_DONE;
 220 }
 221
 222 static 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 static struct notifier_block bcm63xx_wdt_notifier = {
 238         .notifier_call = bcm63xx_wdt_notify_sys,
 239 };
 240
 241
 242 static int bcm63xx_wdt_probe(struct platform_device *pdev)
 243 {
 244         int ret;
 245         struct resource *r;
 246
 247         setup_timer(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0L);
 248
 249         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 250         if (!r) {
 251                 printk(KERN_ERR PFX
 252                         "failed to retrieve resources\n");
 253                 return -ENODEV;
 254         }
 255
 256         bcm63xx_wdt_device.regs = ioremap_nocache(r->start, r->end - r->start);
 257         if (!bcm63xx_wdt_device.regs) {
 258                 printk(KERN_ERR PFX
 259                         "failed to remap I/O resources\n");
 260                 return -ENXIO;
 261         }
 262
 263         if (bcm63xx_wdt_settimeout(wdt_time)) {
 264                 bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
 265                 printk(KERN_INFO PFX
 266                         ": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
 267                         wdt_time);
 268         }
 269
 270         ret = register_reboot_notifier(&bcm63xx_wdt_notifier);
 271         if (ret) {
 272                 printk(KERN_ERR PFX
 273                         "failed to register reboot_notifier\n");
 274                 return ret;
 275         }
 276
 277         ret = misc_register(&bcm63xx_wdt_miscdev);
 278         if (ret < 0) {
 279                 printk(KERN_ERR PFX
 280                         "failed to register watchdog device\n");
 281                 goto unmap;
 282         }
 283
 284         printk(KERN_INFO PFX " started, timer margin: %d sec\n", WDT_DEFAULT_TIME);
 285
 286         return 0;
 287
 288 unmap:
 289         unregister_reboot_notifier(&bcm63xx_wdt_notifier);
 290         iounmap(bcm63xx_wdt_device.regs);
 291         return ret;
 292 }
 293
 294 static int bcm63xx_wdt_remove(struct platform_device *pdev)
 295 {
 296         if (!nowayout)
 297                 bcm63xx_wdt_pause();
 298
 299         misc_deregister(&bcm63xx_wdt_miscdev);
 300
 301         iounmap(bcm63xx_wdt_device.regs);
 302
 303         unregister_reboot_notifier(&bcm63xx_wdt_notifier);
 304
 305         return 0;
 306 }
 307
 308 static struct platform_driver bcm63xx_wdt = {
 309         .probe  = bcm63xx_wdt_probe,
 310         .remove = bcm63xx_wdt_remove,
 311         .driver = {
 312                 .name = "bcm63xx-wdt",
 313         }
 314 };
 315
 316 static int __init bcm63xx_wdt_init(void)
 317 {
 318         return platform_driver_register(&bcm63xx_wdt);
 319 }
 320
 321 static void __exit bcm63xx_wdt_exit(void)
 322 {
 323         platform_driver_unregister(&bcm63xx_wdt);
 324 }
 325
 326 module_init(bcm63xx_wdt_init);
 327 module_exit(bcm63xx_wdt_exit);
 328
 329 MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
 330 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 331 MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
 332 MODULE_LICENSE("GPL");
 333 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 334 MODULE_ALIAS("platform:bcm63xx-wdt");