target/linux/rdc/files-2.6.24/arch/i386/mach-rdc/wdt.c

   1 /*
   2  * RDC321x watchdog driver
   3  *
   4  * Copyright (C) 2007 Florian Fainelli <florian@openwrt.org>
   5  *
   6  * This driver is highly inspired from the cpu5_wdt driver
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21  *
  22  */
  23
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/types.h>
  27 #include <linux/errno.h>
  28 #include <linux/miscdevice.h>
  29 #include <linux/fs.h>
  30 #include <linux/init.h>
  31 #include <linux/ioport.h>
  32 #include <linux/timer.h>
  33 #include <linux/completion.h>
  34 #include <linux/jiffies.h>
  35 #include <linux/platform_device.h>
  36 #include <linux/watchdog.h>
  37
  38 #include <asm/io.h>
  39 #include <asm/uaccess.h>
  40
  41 #include <asm/mach-rdc/rdc321x_defs.h>
  42
  43 #define RDC_WDT_MASK            0x80000000      /* Mask */
  44 #define RDC_WDT_EN              0x00800000      /* Enable bit */
  45 #define RDC_WDT_WTI             0x00200000      /* Generate a CPU reset/NMI/WDT irq when WDT timeout is reached */
  46 #define RDC_WDT_RST             0x00100000      /* Reset bit */
  47 #define RDC_WDT_WIF             0x00040000      /* WDT IRQ Flag */
  48 #define RDC_WDT_IRT             0x00000100      /* IRQ Routing table */
  49 #define RDC_WDT_CNT             0x00000001      /* WDT count */
  50
  51 #define RDC_CLS_TMR             0x80003844      /* Clear timer */
  52
  53 #define RDC_WDT_INTERVAL        (HZ/10+1)
  54
  55 int nowayout = WATCHDOG_NOWAYOUT;
  56 module_param(nowayout, int, 0);
  57 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  58
  59 static int ticks = 1000;
  60
  61 /* some device data */
  62
  63 static struct {
  64         struct completion stop;
  65         volatile int running;
  66         struct timer_list timer;
  67         volatile int queue;
  68         int default_ticks;
  69         unsigned long inuse;
  70 } rdc321x_wdt_device;
  71
  72 /* generic helper functions */
  73
  74 static void rdc321x_wdt_trigger(unsigned long unused)
  75 {
  76         if( rdc321x_wdt_device.running )
  77                 ticks--;
  78
  79         /* keep watchdog alive */
  80         outl(RDC_WDT_EN|inl(RDC3210_CFGREG_DATA), RDC3210_CFGREG_DATA);
  81
  82         /* requeue?? */
  83         if (rdc321x_wdt_device.queue && ticks)
  84                 mod_timer(&rdc321x_wdt_device.timer, jiffies + RDC_WDT_INTERVAL);
  85         else {
  86                 /* ticks doesn't matter anyway */
  87                 complete(&rdc321x_wdt_device.stop);
  88         }
  89
  90 }
  91
  92 static void rdc321x_wdt_reset(void)
  93 {
  94         ticks = rdc321x_wdt_device.default_ticks;
  95 }
  96
  97 static void rdc321x_wdt_start(void)
  98 {
  99         if (!rdc321x_wdt_device.queue) {
 100                 rdc321x_wdt_device.queue = 1;
 101
 102                 /* Clear the timer */
 103                 outl(RDC_CLS_TMR, RDC3210_CFGREG_ADDR);
 104
 105                 /* Enable watchdog and set the timeout to 81.92 us */
 106                 outl(RDC_WDT_EN|RDC_WDT_CNT, RDC3210_CFGREG_DATA);
 107
 108                 mod_timer(&rdc321x_wdt_device.timer, jiffies + RDC_WDT_INTERVAL);
 109         }
 110
 111         /* if process dies, counter is not decremented */
 112         rdc321x_wdt_device.running++;
 113 }
 114
 115 static int rdc321x_wdt_stop(void)
 116 {
 117         if (rdc321x_wdt_device.running)
 118                 rdc321x_wdt_device.running = 0;
 119
 120         ticks = rdc321x_wdt_device.default_ticks;
 121
 122         return -EIO;
 123 }
 124
 125 /* filesystem operations */
 126
 127 static int rdc321x_wdt_open(struct inode *inode, struct file *file)
 128 {
 129         if (test_and_set_bit(0, &rdc321x_wdt_device.inuse))
 130                 return -EBUSY;
 131
 132         return nonseekable_open(inode, file);
 133 }
 134
 135 static int rdc321x_wdt_release(struct inode *inode, struct file *file)
 136 {
 137         clear_bit(0, &rdc321x_wdt_device.inuse);
 138         return 0;
 139 }
 140
 141 static int rdc321x_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 142 {
 143         void __user *argp = (void __user *)arg;
 144         unsigned int value;
 145         static struct watchdog_info ident =
 146         {
 147                 .options = WDIOF_CARDRESET,
 148                 .identity = "RDC321x WDT",
 149         };
 150
 151         switch(cmd) {
 152                 case WDIOC_KEEPALIVE:
 153                         rdc321x_wdt_reset();
 154                         break;
 155                 case WDIOC_GETSTATUS:
 156                         /* Read the value from the DATA register */
 157                         value = inl(RDC3210_CFGREG_DATA);
 158                         if ( copy_to_user(argp, &value, sizeof(int)) )
 159                                 return -EFAULT;
 160                         break;
 161                 case WDIOC_GETSUPPORT:
 162                         if ( copy_to_user(argp, &ident, sizeof(ident)) )
 163                                 return -EFAULT;
 164                         break;
 165                 case WDIOC_SETOPTIONS:
 166                         if ( copy_from_user(&value, argp, sizeof(int)) )
 167                                 return -EFAULT;
 168                         switch(value) {
 169                                 case WDIOS_ENABLECARD:
 170                                         rdc321x_wdt_start();
 171                                         break;
 172                                 case WDIOS_DISABLECARD:
 173                                         return rdc321x_wdt_stop();
 174                                 default:
 175                                         return -EINVAL;
 176                         }
 177                         break;
 178                 default:
 179                         return -ENOTTY;
 180         }
 181         return 0;
 182 }
 183
 184 static ssize_t rdc321x_wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 185 {
 186         if ( !count )
 187                 return -EIO;
 188
 189         rdc321x_wdt_reset();
 190
 191         return count;
 192 }
 193
 194 static const struct file_operations rdc321x_wdt_fops = {
 195         .owner          = THIS_MODULE,
 196         .llseek         = no_llseek,
 197         .ioctl          = rdc321x_wdt_ioctl,
 198         .open           = rdc321x_wdt_open,
 199         .write          = rdc321x_wdt_write,
 200         .release        = rdc321x_wdt_release,
 201 };
 202
 203 static struct miscdevice rdc321x_wdt_misc = {
 204         .minor  = WATCHDOG_MINOR,
 205         .name   = "watchdog",
 206         .fops   = &rdc321x_wdt_fops,
 207 };
 208
 209 static int __devinit rdc321x_wdt_probe(struct platform_device *pdev)
 210 {
 211         int err;
 212
 213         if ( (err = misc_register(&rdc321x_wdt_misc)) < 0 ) {
 214                 printk(KERN_ERR PFX "misc_register failed\n");
 215                 return err;
 216         }
 217
 218         /* Reset the watchdog */
 219         outl(RDC_WDT_RST, RDC3210_CFGREG_DATA);
 220
 221         init_completion(&rdc321x_wdt_device.stop);
 222         rdc321x_wdt_device.queue = 0;
 223
 224         clear_bit(0, &rdc321x_wdt_device.inuse);
 225
 226         setup_timer(&rdc321x_wdt_device.timer, rdc321x_wdt_trigger, 0);
 227
 228         rdc321x_wdt_device.default_ticks = ticks;
 229
 230         printk(KERN_INFO PFX "init success\n");
 231
 232         return 0;
 233 }
 234
 235 static int rdc321x_wdt_remove(struct platform_device *pdev)
 236 {
 237         if (rdc321x_wdt_device.queue) {
 238                 rdc321x_wdt_device.queue = 0;
 239                 wait_for_completion(&rdc321x_wdt_device.stop);
 240         }
 241
 242         misc_deregister(&rdc321x_wdt_misc);
 243
 244         return 0;
 245 }
 246
 247 static struct platform_driver rdc321x_wdt_driver = {
 248         .probe = rdc321x_wdt_probe,
 249         .remove = rdc321x_wdt_remove,
 250         .driver = {
 251                 .owner = THIS_MODULE,
 252                 .name = "rdc321x-wdt",
 253         },
 254 };
 255
 256 static int __init rdc321x_wdt_init(void)
 257 {
 258         return platform_driver_register(&rdc321x_wdt_driver);
 259 }
 260
 261 static void __exit rdc321x_wdt_exit(void)
 262 {
 263         platform_driver_unregister(&rdc321x_wdt_driver);
 264 }
 265
 266 module_init(rdc321x_wdt_init);
 267 module_exit(rdc321x_wdt_exit);
 268
 269 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 270 MODULE_DESCRIPTION("RDC321x watchdog driver");
 271 MODULE_LICENSE("GPL");
 272 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);