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