target/linux/brcm2708/patches-3.10/003-bcm2708-watchdog-driver.patch

   1 --- /dev/null
   2 +++ b/drivers/watchdog/bcm2708_wdog.c
   3 @@ -0,0 +1,385 @@
   4 +/*
   5 + *     Broadcom BCM2708 watchdog driver.
   6 + *
   7 + *     (c) Copyright 2010 Broadcom Europe Ltd
   8 + *
   9 + *     This program is free software; you can redistribute it and/or
  10 + *     modify it under the terms of the GNU General Public License
  11 + *     as published by the Free Software Foundation; either version
  12 + *     2 of the License, or (at your option) any later version.
  13 + *
  14 + *      BCM2708 watchdog driver. Loosely based on wdt driver.
  15 + */
  16 +
  17 +#include <linux/interrupt.h>
  18 +#include <linux/module.h>
  19 +#include <linux/moduleparam.h>
  20 +#include <linux/types.h>
  21 +#include <linux/miscdevice.h>
  22 +#include <linux/watchdog.h>
  23 +#include <linux/fs.h>
  24 +#include <linux/ioport.h>
  25 +#include <linux/notifier.h>
  26 +#include <linux/reboot.h>
  27 +#include <linux/init.h>
  28 +#include <linux/io.h>
  29 +#include <linux/uaccess.h>
  30 +#include <mach/platform.h>
  31 +
  32 +#include <asm/system.h>
  33 +
  34 +#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
  35 +#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
  36 +
  37 +static unsigned long wdog_is_open;
  38 +static uint32_t wdog_ticks;           /* Ticks to load into wdog timer */
  39 +static char expect_close;
  40 +
  41 +/*
  42 + *     Module parameters
  43 + */
  44 +
  45 +#define WD_TIMO 10                    /* Default heartbeat = 60 seconds */
  46 +static int heartbeat = WD_TIMO;               /* Heartbeat in seconds */
  47 +
  48 +module_param(heartbeat, int, 0);
  49 +MODULE_PARM_DESC(heartbeat,
  50 +       "Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default="
  51 +                               __MODULE_STRING(WD_TIMO) ")");
  52 +
  53 +static int nowayout = WATCHDOG_NOWAYOUT;
  54 +module_param(nowayout, int, 0);
  55 +MODULE_PARM_DESC(nowayout,
  56 +       "Watchdog cannot be stopped once started (default="
  57 +                               __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  58 +
  59 +static DEFINE_SPINLOCK(wdog_lock);
  60 +
  61 +/**
  62 + *     Start the watchdog driver.
  63 + */
  64 +
  65 +static int wdog_start(unsigned long timeout)
  66 +{
  67 +       uint32_t cur;
  68 +       unsigned long flags;
  69 +       spin_lock_irqsave(&wdog_lock, flags);
  70 +
  71 +       /* enable the watchdog */
  72 +       iowrite32(PM_PASSWORD | (timeout & PM_WDOG_TIME_SET),
  73 +                 __io_address(PM_WDOG));
  74 +       cur = ioread32(__io_address(PM_RSTC));
  75 +       iowrite32(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) |
  76 +                 PM_RSTC_WRCFG_FULL_RESET, __io_address(PM_RSTC));
  77 +
  78 +       spin_unlock_irqrestore(&wdog_lock, flags);
  79 +       return 0;
  80 +}
  81 +
  82 +/**
  83 + *     Stop the watchdog driver.
  84 + */
  85 +
  86 +static int wdog_stop(void)
  87 +{
  88 +       iowrite32(PM_PASSWORD | PM_RSTC_RESET, __io_address(PM_RSTC));
  89 +       printk(KERN_INFO "watchdog stopped\n");
  90 +       return 0;
  91 +}
  92 +
  93 +/**
  94 + *     Reload counter one with the watchdog heartbeat. We don't bother
  95 + *     reloading the cascade counter.
  96 + */
  97 +
  98 +static void wdog_ping(void)
  99 +{
 100 +       wdog_start(wdog_ticks);
 101 +}
 102 +
 103 +/**
 104 + *     @t:             the new heartbeat value that needs to be set.
 105 + *
 106 + *     Set a new heartbeat value for the watchdog device. If the heartbeat
 107 + *     value is incorrect we keep the old value and return -EINVAL. If
 108 + *     successful we return 0.
 109 + */
 110 +
 111 +static int wdog_set_heartbeat(int t)
 112 +{
 113 +       if (t < 1 || t > WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET))
 114 +               return -EINVAL;
 115 +
 116 +       heartbeat = t;
 117 +       wdog_ticks = SECS_TO_WDOG_TICKS(t);
 118 +       return 0;
 119 +}
 120 +
 121 +/**
 122 + *     @file: file handle to the watchdog
 123 + *     @buf: buffer to write (unused as data does not matter here
 124 + *     @count: count of bytes
 125 + *     @ppos: pointer to the position to write. No seeks allowed
 126 + *
 127 + *     A write to a watchdog device is defined as a keepalive signal.
 128 + *
 129 + *      if 'nowayout' is set then normally a close() is ignored. But
 130 + *      if you write 'V' first then the close() will stop the timer.
 131 + */
 132 +
 133 +static ssize_t wdog_write(struct file *file, const char __user *buf,
 134 +                                               size_t count, loff_t *ppos)
 135 +{
 136 +       if (count) {
 137 +               if (!nowayout) {
 138 +                       size_t i;
 139 +
 140 +                       /* In case it was set long ago */
 141 +                       expect_close = 0;
 142 +
 143 +                       for (i = 0; i != count; i++) {
 144 +                               char c;
 145 +                               if (get_user(c, buf + i))
 146 +                                       return -EFAULT;
 147 +                               if (c == 'V')
 148 +                                       expect_close = 42;
 149 +                       }
 150 +               }
 151 +               wdog_ping();
 152 +       }
 153 +       return count;
 154 +}
 155 +
 156 +static int wdog_get_status(void)
 157 +{
 158 +       unsigned long flags;
 159 +       int status = 0;
 160 +       spin_lock_irqsave(&wdog_lock, flags);
 161 +       /* FIXME: readback reset reason */
 162 +       spin_unlock_irqrestore(&wdog_lock, flags);
 163 +       return status;
 164 +}
 165 +
 166 +static uint32_t wdog_get_remaining(void)
 167 +{
 168 +       uint32_t ret = ioread32(__io_address(PM_WDOG));
 169 +       return ret & PM_WDOG_TIME_SET;
 170 +}
 171 +
 172 +/**
 173 + *     @file: file handle to the device
 174 + *     @cmd: watchdog command
 175 + *     @arg: argument pointer
 176 + *
 177 + *     The watchdog API defines a common set of functions for all watchdogs
 178 + *     according to their available features. We only actually usefully support
 179 + *     querying capabilities and current status.
 180 + */
 181 +
 182 +static long wdog_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 183 +{
 184 +       void __user *argp = (void __user *)arg;
 185 +       int __user *p = argp;
 186 +       int new_heartbeat;
 187 +       int status;
 188 +       int options;
 189 +       uint32_t remaining;
 190 +
 191 +       struct watchdog_info ident = {
 192 +               .options =              WDIOF_SETTIMEOUT|
 193 +                                       WDIOF_MAGICCLOSE|
 194 +                                       WDIOF_KEEPALIVEPING,
 195 +               .firmware_version =     1,
 196 +               .identity =             "BCM2708",
 197 +       };
 198 +
 199 +       switch (cmd) {
 200 +       case WDIOC_GETSUPPORT:
 201 +               return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 202 +       case WDIOC_GETSTATUS:
 203 +               status = wdog_get_status();
 204 +               return put_user(status, p);
 205 +       case WDIOC_GETBOOTSTATUS:
 206 +               return put_user(0, p);
 207 +       case WDIOC_KEEPALIVE:
 208 +               wdog_ping();
 209 +               return 0;
 210 +       case WDIOC_SETTIMEOUT:
 211 +               if (get_user(new_heartbeat, p))
 212 +                       return -EFAULT;
 213 +               if (wdog_set_heartbeat(new_heartbeat))
 214 +                       return -EINVAL;
 215 +               wdog_ping();
 216 +               /* Fall */
 217 +       case WDIOC_GETTIMEOUT:
 218 +               return put_user(heartbeat, p);
 219 +       case WDIOC_GETTIMELEFT:
 220 +               remaining = WDOG_TICKS_TO_SECS(wdog_get_remaining());
 221 +               return put_user(remaining, p);
 222 +       case WDIOC_SETOPTIONS:
 223 +               if (get_user(options, p))
 224 +                       return -EFAULT;
 225 +               if (options & WDIOS_DISABLECARD)
 226 +                       wdog_stop();
 227 +               if (options & WDIOS_ENABLECARD)
 228 +                       wdog_start(wdog_ticks);
 229 +               return 0;
 230 +       default:
 231 +               return -ENOTTY;
 232 +       }
 233 +}
 234 +
 235 +/**
 236 + *     @inode: inode of device
 237 + *     @file: file handle to device
 238 + *
 239 + *     The watchdog device has been opened. The watchdog device is single
 240 + *     open and on opening we load the counters.
 241 + */
 242 +
 243 +static int wdog_open(struct inode *inode, struct file *file)
 244 +{
 245 +       if (test_and_set_bit(0, &wdog_is_open))
 246 +               return -EBUSY;
 247 +       /*
 248 +        *      Activate
 249 +        */
 250 +       wdog_start(wdog_ticks);
 251 +       return nonseekable_open(inode, file);
 252 +}
 253 +
 254 +/**
 255 + *     @inode: inode to board
 256 + *     @file: file handle to board
 257 + *
 258 + *     The watchdog has a configurable API. There is a religious dispute
 259 + *     between people who want their watchdog to be able to shut down and
 260 + *     those who want to be sure if the watchdog manager dies the machine
 261 + *     reboots. In the former case we disable the counters, in the latter
 262 + *     case you have to open it again very soon.
 263 + */
 264 +
 265 +static int wdog_release(struct inode *inode, struct file *file)
 266 +{
 267 +       if (expect_close == 42) {
 268 +               wdog_stop();
 269 +       } else {
 270 +               printk(KERN_CRIT
 271 +                "wdt: WDT device closed unexpectedly.  WDT will not stop!\n");
 272 +               wdog_ping();
 273 +       }
 274 +       clear_bit(0, &wdog_is_open);
 275 +       expect_close = 0;
 276 +       return 0;
 277 +}
 278 +
 279 +/**
 280 + *     @this: our notifier block
 281 + *     @code: the event being reported
 282 + *     @unused: unused
 283 + *
 284 + *     Our notifier is called on system shutdowns. Turn the watchdog
 285 + *     off so that it does not fire during the next reboot.
 286 + */
 287 +
 288 +static int wdog_notify_sys(struct notifier_block *this, unsigned long code,
 289 +       void *unused)
 290 +{
 291 +       if (code == SYS_DOWN || code == SYS_HALT)
 292 +               wdog_stop();
 293 +       return NOTIFY_DONE;
 294 +}
 295 +
 296 +/*
 297 + *     Kernel Interfaces
 298 + */
 299 +
 300 +
 301 +static const struct file_operations wdog_fops = {
 302 +       .owner          = THIS_MODULE,
 303 +       .llseek         = no_llseek,
 304 +       .write          = wdog_write,
 305 +       .unlocked_ioctl = wdog_ioctl,
 306 +       .open           = wdog_open,
 307 +       .release        = wdog_release,
 308 +};
 309 +
 310 +static struct miscdevice wdog_miscdev = {
 311 +       .minor  = WATCHDOG_MINOR,
 312 +       .name   = "watchdog",
 313 +       .fops   = &wdog_fops,
 314 +};
 315 +
 316 +/*
 317 + *     The WDT card needs to learn about soft shutdowns in order to
 318 + *     turn the timebomb registers off.
 319 + */
 320 +
 321 +static struct notifier_block wdog_notifier = {
 322 +       .notifier_call = wdog_notify_sys,
 323 +};
 324 +
 325 +/**
 326 + *     cleanup_module:
 327 + *
 328 + *     Unload the watchdog. You cannot do this with any file handles open.
 329 + *     If your watchdog is set to continue ticking on close and you unload
 330 + *     it, well it keeps ticking. We won't get the interrupt but the board
 331 + *     will not touch PC memory so all is fine. You just have to load a new
 332 + *     module in 60 seconds or reboot.
 333 + */
 334 +
 335 +static void __exit wdog_exit(void)
 336 +{
 337 +       misc_deregister(&wdog_miscdev);
 338 +       unregister_reboot_notifier(&wdog_notifier);
 339 +}
 340 +
 341 +static int __init wdog_init(void)
 342 +{
 343 +       int ret;
 344 +
 345 +       /* Check that the heartbeat value is within it's range;
 346 +          if not reset to the default */
 347 +       if (wdog_set_heartbeat(heartbeat)) {
 348 +               wdog_set_heartbeat(WD_TIMO);
 349 +               printk(KERN_INFO "bcm2708_wdog: heartbeat value must be "
 350 +                       "0 < heartbeat < %d, using %d\n",
 351 +                               WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
 352 +                               WD_TIMO);
 353 +       }
 354 +
 355 +       ret = register_reboot_notifier(&wdog_notifier);
 356 +       if (ret) {
 357 +               printk(KERN_ERR
 358 +                     "wdt: cannot register reboot notifier (err=%d)\n", ret);
 359 +               goto out_reboot;
 360 +       }
 361 +
 362 +       ret = misc_register(&wdog_miscdev);
 363 +       if (ret) {
 364 +               printk(KERN_ERR
 365 +                       "wdt: cannot register miscdev on minor=%d (err=%d)\n",
 366 +                                                       WATCHDOG_MINOR, ret);
 367 +               goto out_misc;
 368 +       }
 369 +
 370 +       printk(KERN_INFO "bcm2708 watchdog, heartbeat=%d sec (nowayout=%d)\n",
 371 +               heartbeat, nowayout);
 372 +       return 0;
 373 +
 374 +out_misc:
 375 +       unregister_reboot_notifier(&wdog_notifier);
 376 +out_reboot:
 377 +       return ret;
 378 +}
 379 +
 380 +module_init(wdog_init);
 381 +module_exit(wdog_exit);
 382 +
 383 +MODULE_AUTHOR("Luke Diamand");
 384 +MODULE_DESCRIPTION("Driver for BCM2708 watchdog");
 385 +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 386 +MODULE_ALIAS_MISCDEV(TEMP_MINOR);
 387 +MODULE_LICENSE("GPL");
 388 +
 389 --- a/drivers/watchdog/Kconfig
 390 +++ b/drivers/watchdog/Kconfig
 391 @@ -391,6 +391,12 @@ config RETU_WATCHDOG
 392           To compile this driver as a module, choose M here: the
 393           module will be called retu_wdt.
 394
 395 +config BCM2708_WDT
 396 +       tristate "BCM2708 Watchdog"
 397 +       depends on ARCH_BCM2708
 398 +       help
 399 +         Enables BCM2708 watchdog support.
 400 +
 401  # AVR32 Architecture
 402
 403  config AT32AP700X_WDT
 404 --- a/drivers/watchdog/Makefile
 405 +++ b/drivers/watchdog/Makefile
 406 @@ -54,6 +54,7 @@ obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_
 407  obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
 408  obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
 409  obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
 410 +obj-$(CONFIG_BCM2708_WDT) += bcm2708_wdog.o
 411
 412  # AVR32 Architecture
 413  obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o