arch/x86/mach-rdc321x/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 #include <linux/io.h>
  38 #include <linux/uaccess.h>
  39
  40 #include <asm/mach-rdc321x/rdc321x_defs.h>
  41
  42 #define RDC_WDT_MASK    0x80000000 /* Mask */
  43 #define RDC_WDT_EN      0x00800000 /* Enable bit */
  44 #define RDC_WDT_WTI     0x00200000 /* Generate CPU reset/NMI/WDT on timeout */
  45 #define RDC_WDT_RST     0x00100000 /* Reset bit */
  46 #define RDC_WDT_WIF     0x00040000 /* WDT IRQ Flag */
  47 #define RDC_WDT_IRT     0x00000100 /* IRQ Routing table */
  48 #define RDC_WDT_CNT     0x00000001 /* WDT count */
  49
  50 #define RDC_CLS_TMR     0x80003844 /* Clear timer */
  51
  52 #define RDC_WDT_INTERVAL        (HZ/10+1)
  53
  54 int nowayout = WATCHDOG_NOWAYOUT;
  55 module_param(nowayout, int, 0);
  56 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  57
  58 static int ticks = 1000;
  59
  60 /* some device data */
  61
  62 static struct {
  63         struct completion stop;
  64         volatile int running;
  65         struct timer_list timer;
  66         volatile int queue;
  67         int default_ticks;
  68         unsigned long inuse;
  69 } rdc321x_wdt_device;
  70
  71 /* generic helper functions */
  72
  73 static void rdc321x_wdt_trigger(unsigned long unused)
  74 {
  75         if (rdc321x_wdt_device.running)
  76                 ticks--;
  77
  78         /* keep watchdog alive */
  79         outl(RDC_WDT_EN|inl(RDC3210_CFGREG_DATA), RDC3210_CFGREG_DATA);
  80
  81         /* requeue?? */
  82         if (rdc321x_wdt_device.queue && ticks)
  83                 mod_timer(&rdc321x_wdt_device.timer,
  84                                 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,
 109                                 jiffies + RDC_WDT_INTERVAL);
 110         }
 111
 112         /* if process dies, counter is not decremented */
 113         rdc321x_wdt_device.running++;
 114 }
 115
 116 static int rdc321x_wdt_stop(void)
 117 {
 118         if (rdc321x_wdt_device.running)
 119                 rdc321x_wdt_device.running = 0;
 120
 121         ticks = rdc321x_wdt_device.default_ticks;
 122
 123         return -EIO;
 124 }
 125
 126 /* filesystem operations */
 127
 128 static int rdc321x_wdt_open(struct inode *inode, struct file *file)
 129 {
 130         if (test_and_set_bit(0, &rdc321x_wdt_device.inuse))
 131                 return -EBUSY;
 132
 133         return nonseekable_open(inode, file);
 134 }
 135
 136 static int rdc321x_wdt_release(struct inode *inode, struct file *file)
 137 {
 138         clear_bit(0, &rdc321x_wdt_device.inuse);
 139         return 0;
 140 }
 141
 142 static int rdc321x_wdt_ioctl(struct inode *inode, struct file *file,
 143                                 unsigned int cmd, unsigned long arg)
 144 {
 145         void __user *argp = (void __user *)arg;
 146         unsigned int value;
 147         static struct watchdog_info ident = {
 148                 .options = WDIOF_CARDRESET,
 149                 .identity = "RDC321x WDT",
 150         };
 151
 152         switch (cmd) {
 153         case WDIOC_KEEPALIVE:
 154                 rdc321x_wdt_reset();
 155                 break;
 156         case WDIOC_GETSTATUS:
 157                 /* Read the value from the DATA register */
 158                 value = inl(RDC3210_CFGREG_DATA);
 159                 if (copy_to_user(argp, &value, sizeof(int)))
 160                         return -EFAULT;
 161                 break;
 162         case WDIOC_GETSUPPORT:
 163                 if (copy_to_user(argp, &ident, sizeof(ident)))
 164                         return -EFAULT;
 165                 break;
 166         case WDIOC_SETOPTIONS:
 167                 if (copy_from_user(&value, argp, sizeof(int)))
 168                         return -EFAULT;
 169                 switch (value) {
 170                 case WDIOS_ENABLECARD:
 171                         rdc321x_wdt_start();
 172                         break;
 173                 case WDIOS_DISABLECARD:
 174                         return rdc321x_wdt_stop();
 175                 default:
 176                         return -EINVAL;
 177                 }
 178                 break;
 179         default:
 180                 return -ENOTTY;
 181         }
 182         return 0;
 183 }
 184
 185 static ssize_t rdc321x_wdt_write(struct file *file, const char __user *buf,
 186                                 size_t count, loff_t *ppos)
 187 {
 188         if (!count)
 189                 return -EIO;
 190
 191         rdc321x_wdt_reset();
 192
 193         return count;
 194 }
 195
 196 static const struct file_operations rdc321x_wdt_fops = {
 197         .owner          = THIS_MODULE,
 198         .llseek         = no_llseek,
 199         .ioctl          = rdc321x_wdt_ioctl,
 200         .open           = rdc321x_wdt_open,
 201         .write          = rdc321x_wdt_write,
 202         .release        = rdc321x_wdt_release,
 203 };
 204
 205 static struct miscdevice rdc321x_wdt_misc = {
 206         .minor  = WATCHDOG_MINOR,
 207         .name   = "watchdog",
 208         .fops   = &rdc321x_wdt_fops,
 209 };
 210
 211 static int __devinit rdc321x_wdt_probe(struct platform_device *pdev)
 212 {
 213         int err;
 214
 215         err = misc_register(&rdc321x_wdt_misc);
 216         if (err < 0) {
 217                 printk(KERN_ERR PFX "watchdog misc_register failed\n");
 218                 return err;
 219         }
 220
 221         /* Reset the watchdog */
 222         outl(RDC_WDT_RST, RDC3210_CFGREG_DATA);
 223
 224         init_completion(&rdc321x_wdt_device.stop);
 225         rdc321x_wdt_device.queue = 0;
 226
 227         clear_bit(0, &rdc321x_wdt_device.inuse);
 228
 229         setup_timer(&rdc321x_wdt_device.timer, rdc321x_wdt_trigger, 0);
 230
 231         rdc321x_wdt_device.default_ticks = ticks;
 232
 233         printk(KERN_INFO PFX "watchdog init success\n");
 234
 235         return 0;
 236 }
 237
 238 static int rdc321x_wdt_remove(struct platform_device *pdev)
 239 {
 240         if (rdc321x_wdt_device.queue) {
 241                 rdc321x_wdt_device.queue = 0;
 242                 wait_for_completion(&rdc321x_wdt_device.stop);
 243         }
 244
 245         misc_deregister(&rdc321x_wdt_misc);
 246
 247         return 0;
 248 }
 249
 250 static struct platform_driver rdc321x_wdt_driver = {
 251         .probe = rdc321x_wdt_probe,
 252         .remove = rdc321x_wdt_remove,
 253         .driver = {
 254                 .owner = THIS_MODULE,
 255                 .name = "rdc321x-wdt",
 256         },
 257 };
 258
 259 static int __init rdc321x_wdt_init(void)
 260 {
 261         return platform_driver_register(&rdc321x_wdt_driver);
 262 }
 263
 264 static void __exit rdc321x_wdt_exit(void)
 265 {
 266         platform_driver_unregister(&rdc321x_wdt_driver);
 267 }
 268
 269 module_init(rdc321x_wdt_init);
 270 module_exit(rdc321x_wdt_exit);
 271
 272 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 273 MODULE_DESCRIPTION("RDC321x watchdog driver");
 274 MODULE_LICENSE("GPL");
 275 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);