target/linux/brcm2708/patches-3.10/0003-bcm2708-watchdog-driver.patch

   1 From dd611b3364087514ef5fc59c6106d8924d2a2a30 Mon Sep 17 00:00:00 2001
   2 From: popcornmix <popcornmix@gmail.com>
   3 Date: Wed, 1 May 2013 19:54:32 +0100
   4 Subject: [PATCH 003/174] bcm2708 watchdog driver
   5
   6 Signed-off-by: popcornmix <popcornmix@gmail.com>
   7 ---
   8  drivers/watchdog/Kconfig        |   6 +
   9  drivers/watchdog/Makefile       |   1 +
  10  drivers/watchdog/bcm2708_wdog.c | 385 ++++++++++++++++++++++++++++++++++++++++
  11  3 files changed, 392 insertions(+)
  12  create mode 100644 drivers/watchdog/bcm2708_wdog.c
  13
  14 --- a/drivers/watchdog/Kconfig
  15 +++ b/drivers/watchdog/Kconfig
  16 @@ -391,6 +391,12 @@ config RETU_WATCHDOG
  17           To compile this driver as a module, choose M here: the
  18           module will be called retu_wdt.
  19
  20 +config BCM2708_WDT
  21 +       tristate "BCM2708 Watchdog"
  22 +       depends on ARCH_BCM2708
  23 +       help
  24 +         Enables BCM2708 watchdog support.
  25 +
  26  # AVR32 Architecture
  27
  28  config AT32AP700X_WDT
  29 --- a/drivers/watchdog/Makefile
  30 +++ b/drivers/watchdog/Makefile
  31 @@ -54,6 +54,7 @@ obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_
  32  obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
  33  obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
  34  obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
  35 +obj-$(CONFIG_BCM2708_WDT) += bcm2708_wdog.o
  36
  37  # AVR32 Architecture
  38  obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
  39 --- /dev/null
  40 +++ b/drivers/watchdog/bcm2708_wdog.c
  41 @@ -0,0 +1,385 @@
  42 +/*
  43 + *     Broadcom BCM2708 watchdog driver.
  44 + *
  45 + *     (c) Copyright 2010 Broadcom Europe Ltd
  46 + *
  47 + *     This program is free software; you can redistribute it and/or
  48 + *     modify it under the terms of the GNU General Public License
  49 + *     as published by the Free Software Foundation; either version
  50 + *     2 of the License, or (at your option) any later version.
  51 + *
  52 + *      BCM2708 watchdog driver. Loosely based on wdt driver.
  53 + */
  54 +
  55 +#include <linux/interrupt.h>
  56 +#include <linux/module.h>
  57 +#include <linux/moduleparam.h>
  58 +#include <linux/types.h>
  59 +#include <linux/miscdevice.h>
  60 +#include <linux/watchdog.h>
  61 +#include <linux/fs.h>
  62 +#include <linux/ioport.h>
  63 +#include <linux/notifier.h>
  64 +#include <linux/reboot.h>
  65 +#include <linux/init.h>
  66 +#include <linux/io.h>
  67 +#include <linux/uaccess.h>
  68 +#include <mach/platform.h>
  69 +
  70 +#include <asm/system.h>
  71 +
  72 +#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
  73 +#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
  74 +
  75 +static unsigned long wdog_is_open;
  76 +static uint32_t wdog_ticks;           /* Ticks to load into wdog timer */
  77 +static char expect_close;
  78 +
  79 +/*
  80 + *     Module parameters
  81 + */
  82 +
  83 +#define WD_TIMO 10                    /* Default heartbeat = 60 seconds */
  84 +static int heartbeat = WD_TIMO;               /* Heartbeat in seconds */
  85 +
  86 +module_param(heartbeat, int, 0);
  87 +MODULE_PARM_DESC(heartbeat,
  88 +       "Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default="
  89 +                               __MODULE_STRING(WD_TIMO) ")");
  90 +
  91 +static int nowayout = WATCHDOG_NOWAYOUT;
  92 +module_param(nowayout, int, 0);
  93 +MODULE_PARM_DESC(nowayout,
  94 +       "Watchdog cannot be stopped once started (default="
  95 +                               __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  96 +
  97 +static DEFINE_SPINLOCK(wdog_lock);
  98 +
  99 +/**
 100 + *     Start the watchdog driver.
 101 + */
 102 +
 103 +static int wdog_start(unsigned long timeout)
 104 +{
 105 +       uint32_t cur;
 106 +       unsigned long flags;
 107 +       spin_lock_irqsave(&wdog_lock, flags);
 108 +
 109 +       /* enable the watchdog */
 110 +       iowrite32(PM_PASSWORD | (timeout & PM_WDOG_TIME_SET),
 111 +                 __io_address(PM_WDOG));
 112 +       cur = ioread32(__io_address(PM_RSTC));
 113 +       iowrite32(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) |
 114 +                 PM_RSTC_WRCFG_FULL_RESET, __io_address(PM_RSTC));
 115 +
 116 +       spin_unlock_irqrestore(&wdog_lock, flags);
 117 +       return 0;
 118 +}
 119 +
 120 +/**
 121 + *     Stop the watchdog driver.
 122 + */
 123 +
 124 +static int wdog_stop(void)
 125 +{
 126 +       iowrite32(PM_PASSWORD | PM_RSTC_RESET, __io_address(PM_RSTC));
 127 +       printk(KERN_INFO "watchdog stopped\n");
 128 +       return 0;
 129 +}
 130 +
 131 +/**
 132 + *     Reload counter one with the watchdog heartbeat. We don't bother
 133 + *     reloading the cascade counter.
 134 + */
 135 +
 136 +static void wdog_ping(void)
 137 +{
 138 +       wdog_start(wdog_ticks);
 139 +}
 140 +
 141 +/**
 142 + *     @t:             the new heartbeat value that needs to be set.
 143 + *
 144 + *     Set a new heartbeat value for the watchdog device. If the heartbeat
 145 + *     value is incorrect we keep the old value and return -EINVAL. If
 146 + *     successful we return 0.
 147 + */
 148 +
 149 +static int wdog_set_heartbeat(int t)
 150 +{
 151 +       if (t < 1 || t > WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET))
 152 +               return -EINVAL;
 153 +
 154 +       heartbeat = t;
 155 +       wdog_ticks = SECS_TO_WDOG_TICKS(t);
 156 +       return 0;
 157 +}
 158 +
 159 +/**
 160 + *     @file: file handle to the watchdog
 161 + *     @buf: buffer to write (unused as data does not matter here
 162 + *     @count: count of bytes
 163 + *     @ppos: pointer to the position to write. No seeks allowed
 164 + *
 165 + *     A write to a watchdog device is defined as a keepalive signal.
 166 + *
 167 + *      if 'nowayout' is set then normally a close() is ignored. But
 168 + *      if you write 'V' first then the close() will stop the timer.
 169 + */
 170 +
 171 +static ssize_t wdog_write(struct file *file, const char __user *buf,
 172 +                                               size_t count, loff_t *ppos)
 173 +{
 174 +       if (count) {
 175 +               if (!nowayout) {
 176 +                       size_t i;
 177 +
 178 +                       /* In case it was set long ago */
 179 +                       expect_close = 0;
 180 +
 181 +                       for (i = 0; i != count; i++) {
 182 +                               char c;
 183 +                               if (get_user(c, buf + i))
 184 +                                       return -EFAULT;
 185 +                               if (c == 'V')
 186 +                                       expect_close = 42;
 187 +                       }
 188 +               }
 189 +               wdog_ping();
 190 +       }
 191 +       return count;
 192 +}
 193 +
 194 +static int wdog_get_status(void)
 195 +{
 196 +       unsigned long flags;
 197 +       int status = 0;
 198 +       spin_lock_irqsave(&wdog_lock, flags);
 199 +       /* FIXME: readback reset reason */
 200 +       spin_unlock_irqrestore(&wdog_lock, flags);
 201 +       return status;
 202 +}
 203 +
 204 +static uint32_t wdog_get_remaining(void)
 205 +{
 206 +       uint32_t ret = ioread32(__io_address(PM_WDOG));
 207 +       return ret & PM_WDOG_TIME_SET;
 208 +}
 209 +
 210 +/**
 211 + *     @file: file handle to the device
 212 + *     @cmd: watchdog command
 213 + *     @arg: argument pointer
 214 + *
 215 + *     The watchdog API defines a common set of functions for all watchdogs
 216 + *     according to their available features. We only actually usefully support
 217 + *     querying capabilities and current status.
 218 + */
 219 +
 220 +static long wdog_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 221 +{
 222 +       void __user *argp = (void __user *)arg;
 223 +       int __user *p = argp;
 224 +       int new_heartbeat;
 225 +       int status;
 226 +       int options;
 227 +       uint32_t remaining;
 228 +
 229 +       struct watchdog_info ident = {
 230 +               .options =              WDIOF_SETTIMEOUT|
 231 +                                       WDIOF_MAGICCLOSE|
 232 +                                       WDIOF_KEEPALIVEPING,
 233 +               .firmware_version =     1,
 234 +               .identity =             "BCM2708",
 235 +       };
 236 +
 237 +       switch (cmd) {
 238 +       case WDIOC_GETSUPPORT:
 239 +               return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 240 +       case WDIOC_GETSTATUS:
 241 +               status = wdog_get_status();
 242 +               return put_user(status, p);
 243 +       case WDIOC_GETBOOTSTATUS:
 244 +               return put_user(0, p);
 245 +       case WDIOC_KEEPALIVE:
 246 +               wdog_ping();
 247 +               return 0;
 248 +       case WDIOC_SETTIMEOUT:
 249 +               if (get_user(new_heartbeat, p))
 250 +                       return -EFAULT;
 251 +               if (wdog_set_heartbeat(new_heartbeat))
 252 +                       return -EINVAL;
 253 +               wdog_ping();
 254 +               /* Fall */
 255 +       case WDIOC_GETTIMEOUT:
 256 +               return put_user(heartbeat, p);
 257 +       case WDIOC_GETTIMELEFT:
 258 +               remaining = WDOG_TICKS_TO_SECS(wdog_get_remaining());
 259 +               return put_user(remaining, p);
 260 +       case WDIOC_SETOPTIONS:
 261 +               if (get_user(options, p))
 262 +                       return -EFAULT;
 263 +               if (options & WDIOS_DISABLECARD)
 264 +                       wdog_stop();
 265 +               if (options & WDIOS_ENABLECARD)
 266 +                       wdog_start(wdog_ticks);
 267 +               return 0;
 268 +       default:
 269 +               return -ENOTTY;
 270 +       }
 271 +}
 272 +
 273 +/**
 274 + *     @inode: inode of device
 275 + *     @file: file handle to device
 276 + *
 277 + *     The watchdog device has been opened. The watchdog device is single
 278 + *     open and on opening we load the counters.
 279 + */
 280 +
 281 +static int wdog_open(struct inode *inode, struct file *file)
 282 +{
 283 +       if (test_and_set_bit(0, &wdog_is_open))
 284 +               return -EBUSY;
 285 +       /*
 286 +        *      Activate
 287 +        */
 288 +       wdog_start(wdog_ticks);
 289 +       return nonseekable_open(inode, file);
 290 +}
 291 +
 292 +/**
 293 + *     @inode: inode to board
 294 + *     @file: file handle to board
 295 + *
 296 + *     The watchdog has a configurable API. There is a religious dispute
 297 + *     between people who want their watchdog to be able to shut down and
 298 + *     those who want to be sure if the watchdog manager dies the machine
 299 + *     reboots. In the former case we disable the counters, in the latter
 300 + *     case you have to open it again very soon.
 301 + */
 302 +
 303 +static int wdog_release(struct inode *inode, struct file *file)
 304 +{
 305 +       if (expect_close == 42) {
 306 +               wdog_stop();
 307 +       } else {
 308 +               printk(KERN_CRIT
 309 +                "wdt: WDT device closed unexpectedly.  WDT will not stop!\n");
 310 +               wdog_ping();
 311 +       }
 312 +       clear_bit(0, &wdog_is_open);
 313 +       expect_close = 0;
 314 +       return 0;
 315 +}
 316 +
 317 +/**
 318 + *     @this: our notifier block
 319 + *     @code: the event being reported
 320 + *     @unused: unused
 321 + *
 322 + *     Our notifier is called on system shutdowns. Turn the watchdog
 323 + *     off so that it does not fire during the next reboot.
 324 + */
 325 +
 326 +static int wdog_notify_sys(struct notifier_block *this, unsigned long code,
 327 +       void *unused)
 328 +{
 329 +       if (code == SYS_DOWN || code == SYS_HALT)
 330 +               wdog_stop();
 331 +       return NOTIFY_DONE;
 332 +}
 333 +
 334 +/*
 335 + *     Kernel Interfaces
 336 + */
 337 +
 338 +
 339 +static const struct file_operations wdog_fops = {
 340 +       .owner          = THIS_MODULE,
 341 +       .llseek         = no_llseek,
 342 +       .write          = wdog_write,
 343 +       .unlocked_ioctl = wdog_ioctl,
 344 +       .open           = wdog_open,
 345 +       .release        = wdog_release,
 346 +};
 347 +
 348 +static struct miscdevice wdog_miscdev = {
 349 +       .minor  = WATCHDOG_MINOR,
 350 +       .name   = "watchdog",
 351 +       .fops   = &wdog_fops,
 352 +};
 353 +
 354 +/*
 355 + *     The WDT card needs to learn about soft shutdowns in order to
 356 + *     turn the timebomb registers off.
 357 + */
 358 +
 359 +static struct notifier_block wdog_notifier = {
 360 +       .notifier_call = wdog_notify_sys,
 361 +};
 362 +
 363 +/**
 364 + *     cleanup_module:
 365 + *
 366 + *     Unload the watchdog. You cannot do this with any file handles open.
 367 + *     If your watchdog is set to continue ticking on close and you unload
 368 + *     it, well it keeps ticking. We won't get the interrupt but the board
 369 + *     will not touch PC memory so all is fine. You just have to load a new
 370 + *     module in 60 seconds or reboot.
 371 + */
 372 +
 373 +static void __exit wdog_exit(void)
 374 +{
 375 +       misc_deregister(&wdog_miscdev);
 376 +       unregister_reboot_notifier(&wdog_notifier);
 377 +}
 378 +
 379 +static int __init wdog_init(void)
 380 +{
 381 +       int ret;
 382 +
 383 +       /* Check that the heartbeat value is within it's range;
 384 +          if not reset to the default */
 385 +       if (wdog_set_heartbeat(heartbeat)) {
 386 +               wdog_set_heartbeat(WD_TIMO);
 387 +               printk(KERN_INFO "bcm2708_wdog: heartbeat value must be "
 388 +                       "0 < heartbeat < %d, using %d\n",
 389 +                               WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
 390 +                               WD_TIMO);
 391 +       }
 392 +
 393 +       ret = register_reboot_notifier(&wdog_notifier);
 394 +       if (ret) {
 395 +               printk(KERN_ERR
 396 +                     "wdt: cannot register reboot notifier (err=%d)\n", ret);
 397 +               goto out_reboot;
 398 +       }
 399 +
 400 +       ret = misc_register(&wdog_miscdev);
 401 +       if (ret) {
 402 +               printk(KERN_ERR
 403 +                       "wdt: cannot register miscdev on minor=%d (err=%d)\n",
 404 +                                                       WATCHDOG_MINOR, ret);
 405 +               goto out_misc;
 406 +       }
 407 +
 408 +       printk(KERN_INFO "bcm2708 watchdog, heartbeat=%d sec (nowayout=%d)\n",
 409 +               heartbeat, nowayout);
 410 +       return 0;
 411 +
 412 +out_misc:
 413 +       unregister_reboot_notifier(&wdog_notifier);
 414 +out_reboot:
 415 +       return ret;
 416 +}
 417 +
 418 +module_init(wdog_init);
 419 +module_exit(wdog_exit);
 420 +
 421 +MODULE_AUTHOR("Luke Diamand");
 422 +MODULE_DESCRIPTION("Driver for BCM2708 watchdog");
 423 +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 424 +MODULE_ALIAS_MISCDEV(TEMP_MINOR);
 425 +MODULE_LICENSE("GPL");
 426 +