git.oblomov.eu Git - linux-2.6/blob - drivers/watchdog/rc32434_wdt.c

   1 /*
   2  *  IDT Interprise 79RC32434 watchdog driver
   3  *
   4  *  Copyright (C) 2006, Ondrej Zajicek <santiago@crfreenet.org>
   5  *  Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
   6  *
   7  *  based on
   8  *  SoftDog 0.05:       A Software Watchdog Device
   9  *
  10  *  (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
  11  *                                      All Rights Reserved.
  12  *
  13  *  This program is free software; you can redistribute it and/or
  14  *  modify it under the terms of the GNU General Public License
  15  *  as published by the Free Software Foundation; either version
  16  *  2 of the License, or (at your option) any later version.
  17  *
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/types.h>
  22 #include <linux/kernel.h>
  23 #include <linux/fs.h>
  24 #include <linux/mm.h>
  25 #include <linux/miscdevice.h>
  26 #include <linux/watchdog.h>
  27 #include <linux/reboot.h>
  28 #include <linux/smp_lock.h>
  29 #include <linux/init.h>
  30 #include <linux/platform_device.h>
  31 #include <linux/uaccess.h>
  32
  33 #include <asm/bootinfo.h>
  34 #include <asm/time.h>
  35 #include <asm/mach-rc32434/integ.h>
  36
  37 #define MAX_TIMEOUT                     20
  38 #define RC32434_WDT_INTERVAL            (15 * HZ)
  39
  40 #define VERSION "0.2"
  41
  42 static struct {
  43         struct completion stop;
  44         int running;
  45         struct timer_list timer;
  46         int queue;
  47         int default_ticks;
  48         unsigned long inuse;
  49 } rc32434_wdt_device;
  50
  51 static struct integ __iomem *wdt_reg;
  52 static int ticks = 100 * HZ;
  53
  54 static int expect_close;
  55 static int timeout;
  56
  57 static int nowayout = WATCHDOG_NOWAYOUT;
  58 module_param(nowayout, int, 0);
  59 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  60         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  61
  62
  63 static void rc32434_wdt_start(void)
  64 {
  65         u32 val;
  66
  67         if (!rc32434_wdt_device.inuse) {
  68                 writel(0, &wdt_reg->wtcount);
  69
  70                 val = RC32434_ERR_WRE;
  71                 writel(readl(&wdt_reg->errcs) | val, &wdt_reg->errcs);
  72
  73                 val = RC32434_WTC_EN;
  74                 writel(readl(&wdt_reg->wtc) | val, &wdt_reg->wtc);
  75         }
  76         rc32434_wdt_device.running++;
  77 }
  78
  79 static void rc32434_wdt_stop(void)
  80 {
  81         u32 val;
  82
  83         if (rc32434_wdt_device.running) {
  84
  85                 val = ~RC32434_WTC_EN;
  86                 writel(readl(&wdt_reg->wtc) & val, &wdt_reg->wtc);
  87
  88                 val = ~RC32434_ERR_WRE;
  89                 writel(readl(&wdt_reg->errcs) & val, &wdt_reg->errcs);
  90
  91                 rc32434_wdt_device.running = 0;
  92         }
  93 }
  94
  95 static void rc32434_wdt_set(int new_timeout)
  96 {
  97         u32 cmp = new_timeout * HZ;
  98         u32 state, val;
  99
 100         timeout = new_timeout;
 101         /*
 102          * store and disable WTC
 103          */
 104         state = (u32)(readl(&wdt_reg->wtc) & RC32434_WTC_EN);
 105         val = ~RC32434_WTC_EN;
 106         writel(readl(&wdt_reg->wtc) & val, &wdt_reg->wtc);
 107
 108         writel(0, &wdt_reg->wtcount);
 109         writel(cmp, &wdt_reg->wtcompare);
 110
 111         /*
 112          * restore WTC
 113          */
 114
 115         writel(readl(&wdt_reg->wtc) | state, &wdt_reg);
 116 }
 117
 118 static void rc32434_wdt_reset(void)
 119 {
 120         ticks = rc32434_wdt_device.default_ticks;
 121 }
 122
 123 static void rc32434_wdt_update(unsigned long unused)
 124 {
 125         if (rc32434_wdt_device.running)
 126                 ticks--;
 127
 128         writel(0, &wdt_reg->wtcount);
 129
 130         if (rc32434_wdt_device.queue && ticks)
 131                 mod_timer(&rc32434_wdt_device.timer,
 132                         jiffies + RC32434_WDT_INTERVAL);
 133         else
 134                 complete(&rc32434_wdt_device.stop);
 135 }
 136
 137 static int rc32434_wdt_open(struct inode *inode, struct file *file)
 138 {
 139         if (test_and_set_bit(0, &rc32434_wdt_device.inuse))
 140                 return -EBUSY;
 141
 142         if (nowayout)
 143                 __module_get(THIS_MODULE);
 144
 145         return nonseekable_open(inode, file);
 146 }
 147
 148 static int rc32434_wdt_release(struct inode *inode, struct file *file)
 149 {
 150         if (expect_close && nowayout == 0) {
 151                 rc32434_wdt_stop();
 152                 printk(KERN_INFO KBUILD_MODNAME ": disabling watchdog timer\n");
 153                 module_put(THIS_MODULE);
 154         } else
 155                 printk(KERN_CRIT KBUILD_MODNAME
 156                         ": device closed unexpectedly. WDT will not stop !\n");
 157
 158         clear_bit(0, &rc32434_wdt_device.inuse);
 159         return 0;
 160 }
 161
 162 static ssize_t rc32434_wdt_write(struct file *file, const char *data,
 163                                 size_t len, loff_t *ppos)
 164 {
 165         if (len) {
 166                 if (!nowayout) {
 167                         size_t i;
 168
 169                         /* In case it was set long ago */
 170                         expect_close = 0;
 171
 172                         for (i = 0; i != len; i++) {
 173                                 char c;
 174                                 if (get_user(c, data + i))
 175                                         return -EFAULT;
 176                                 if (c == 'V')
 177                                         expect_close = 1;
 178                         }
 179                 }
 180                 rc32434_wdt_update(0);
 181                 return len;
 182         }
 183         return 0;
 184 }
 185
 186 static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd,
 187                                 unsigned long arg)
 188 {
 189         void __user *argp = (void __user *)arg;
 190         int new_timeout;
 191         unsigned int value;
 192         static struct watchdog_info ident = {
 193                 .options =              WDIOF_SETTIMEOUT |
 194                                         WDIOF_KEEPALIVEPING |
 195                                         WDIOF_MAGICCLOSE,
 196                 .identity =             "RC32434_WDT Watchdog",
 197         };
 198         switch (cmd) {
 199         case WDIOC_KEEPALIVE:
 200                 rc32434_wdt_reset();
 201                 break;
 202         case WDIOC_GETSTATUS:
 203         case WDIOC_GETBOOTSTATUS:
 204                 value = readl(&wdt_reg->wtcount);
 205                 if (copy_to_user(argp, &value, sizeof(int)))
 206                         return -EFAULT;
 207                 break;
 208         case WDIOC_GETSUPPORT:
 209                 if (copy_to_user(argp, &ident, sizeof(ident)))
 210                         return -EFAULT;
 211                 break;
 212         case WDIOC_SETOPTIONS:
 213                 if (copy_from_user(&value, argp, sizeof(int)))
 214                         return -EFAULT;
 215                 switch (value) {
 216                 case WDIOS_ENABLECARD:
 217                         rc32434_wdt_start();
 218                         break;
 219                 case WDIOS_DISABLECARD:
 220                         rc32434_wdt_stop();
 221                 default:
 222                         return -EINVAL;
 223                 }
 224                 break;
 225         case WDIOC_SETTIMEOUT:
 226                 if (copy_from_user(&new_timeout, argp, sizeof(int)))
 227                         return -EFAULT;
 228                 if (new_timeout < 1)
 229                         return -EINVAL;
 230                 if (new_timeout > MAX_TIMEOUT)
 231                         return -EINVAL;
 232                 rc32434_wdt_set(new_timeout);
 233         case WDIOC_GETTIMEOUT:
 234                 return copy_to_user(argp, &timeout, sizeof(int));
 235         default:
 236                 return -ENOTTY;
 237         }
 238
 239         return 0;
 240 }
 241
 242 static struct file_operations rc32434_wdt_fops = {
 243         .owner          = THIS_MODULE,
 244         .llseek         = no_llseek,
 245         .write          = rc32434_wdt_write,
 246         .unlocked_ioctl = rc32434_wdt_ioctl,
 247         .open           = rc32434_wdt_open,
 248         .release        = rc32434_wdt_release,
 249 };
 250
 251 static struct miscdevice rc32434_wdt_miscdev = {
 252         .minor  = WATCHDOG_MINOR,
 253         .name   = "watchdog",
 254         .fops   = &rc32434_wdt_fops,
 255 };
 256
 257 static char banner[] = KERN_INFO KBUILD_MODNAME
 258                 ": Watchdog Timer version " VERSION ", timer margin: %d sec\n";
 259
 260 static int rc32434_wdt_probe(struct platform_device *pdev)
 261 {
 262         int ret;
 263         struct resource *r;
 264
 265         r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rb500_wdt_res");
 266         if (!r) {
 267                 printk(KERN_ERR KBUILD_MODNAME
 268                         "failed to retrieve resources\n");
 269                 return -ENODEV;
 270         }
 271
 272         wdt_reg = ioremap_nocache(r->start, r->end - r->start);
 273         if (!wdt_reg) {
 274                 printk(KERN_ERR KBUILD_MODNAME
 275                         "failed to remap I/O resources\n");
 276                 return -ENXIO;
 277         }
 278
 279         ret = misc_register(&rc32434_wdt_miscdev);
 280
 281         if (ret < 0) {
 282                 printk(KERN_ERR KBUILD_MODNAME
 283                         "failed to register watchdog device\n");
 284                 goto unmap;
 285         }
 286
 287         init_completion(&rc32434_wdt_device.stop);
 288         rc32434_wdt_device.queue = 0;
 289
 290         clear_bit(0, &rc32434_wdt_device.inuse);
 291
 292         setup_timer(&rc32434_wdt_device.timer, rc32434_wdt_update, 0L);
 293
 294         rc32434_wdt_device.default_ticks = ticks;
 295
 296         rc32434_wdt_start();
 297
 298         printk(banner, timeout);
 299
 300         return 0;
 301
 302 unmap:
 303         iounmap(wdt_reg);
 304         return ret;
 305 }
 306
 307 static int rc32434_wdt_remove(struct platform_device *pdev)
 308 {
 309         if (rc32434_wdt_device.queue) {
 310                 rc32434_wdt_device.queue = 0;
 311                 wait_for_completion(&rc32434_wdt_device.stop);
 312         }
 313         misc_deregister(&rc32434_wdt_miscdev);
 314
 315         iounmap(wdt_reg);
 316
 317         return 0;
 318 }
 319
 320 static struct platform_driver rc32434_wdt = {
 321         .probe  = rc32434_wdt_probe,
 322         .remove = rc32434_wdt_remove,
 323         .driver = {
 324                 .name = "rc32434_wdt",
 325         }
 326 };
 327
 328 static int __init rc32434_wdt_init(void)
 329 {
 330         return platform_driver_register(&rc32434_wdt);
 331 }
 332
 333 static void __exit rc32434_wdt_exit(void)
 334 {
 335         platform_driver_unregister(&rc32434_wdt);
 336 }
 337
 338 module_init(rc32434_wdt_init);
 339 module_exit(rc32434_wdt_exit);
 340
 341 MODULE_AUTHOR("Ondrej Zajicek <santiago@crfreenet.org>,"
 342                 "Florian Fainelli <florian@openwrt.org>");
 343 MODULE_DESCRIPTION("Driver for the IDT RC32434 SoC watchdog");
 344 MODULE_LICENSE("GPL");
 345 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);