target/linux/easygate-2.6/files/arch/mips/bcm963xx/wdt.c

   1 /*
   2  * Watchdog driver for the BCM963xx devices
   3  *
   4  * Copyright (C) 2007 OpenWrt.org
   5  *                      Florian Fainelli <florian@openwrt.org>
   6  *
   7  * This program is free software; you can redistribute  it and/or modify it
   8  * under  the terms of  the GNU General  Public License as published by the
   9  * Free Software Foundation;  either version 2 of the  License, or (at your
  10  * option) any later version.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/types.h>
  15 #include <linux/errno.h>
  16 #include <linux/miscdevice.h>
  17 #include <linux/fs.h>
  18 #include <linux/init.h>
  19 #include <linux/notifier.h>
  20 #include <linux/watchdog.h>
  21 #include <linux/timer.h>
  22 #include <linux/jiffies.h>
  23 #include <linux/completion.h>
  24 #include <linux/ioport.h>
  25
  26 typedef struct bcm963xx_timer {
  27         unsigned short unused0;
  28         unsigned char  timer_mask;
  29 #define TIMER0EN        0x01
  30 #define TIMER1EN        0x02
  31 #define TIMER2EN        0x04
  32         unsigned char  timer_ints;
  33 #define TIMER0          0x01
  34 #define TIMER1          0x02
  35 #define TIMER2          0x04
  36 #define WATCHDOG        0x08
  37         unsigned long   timer_ctl0;
  38         unsigned long   timer_ctl1;
  39         unsigned long   timer_ctl2;
  40 #define TIMERENABLE     0x80000000
  41 #define RSTCNTCLR       0x40000000
  42         unsigned long   timer_cnt0;
  43         unsigned long   timer_cnt1;
  44         unsigned long   timer_cnt2;
  45         unsigned long   wdt_def_count;
  46
  47         /* Write 0xff00 0x00ff to Start timer
  48         * Write 0xee00 0x00ee to Stop and re-load default count
  49         * Read from this register returns current watch dog count
  50         */
  51         unsigned long   wdt_ctl;
  52
  53         /* Number of 40-MHz ticks for WD Reset pulse to last */
  54         unsigned long   wdt_rst_count;
  55 } bcm963xx_timer;
  56
  57 static struct bcm963xx_wdt_device {
  58         struct completion stop;
  59         volatile int running;
  60         struct timer_list timer;
  61         volatile int queue;
  62         int default_ticks;
  63         unsigned long inuse;
  64 } bcm963xx_wdt_device;
  65
  66 static int ticks = 1000;
  67
  68 #define WDT_BASE        0xfffe0200
  69 #define WDT             ((volatile bcm963xx_timer * const) WDT_BASE)
  70
  71 #define BCM963XX_INTERVAL        (HZ/10+1)
  72
  73 static void bcm963xx_wdt_trigger(unsigned long unused)
  74 {
  75         if (bcm963xx_wdt_device.running)
  76                 ticks--;
  77
  78         /* Load the default ticking value into the reset counter register */
  79         WDT->wdt_rst_count = bcm963xx_wdt_device.default_ticks;
  80
  81         if (bcm963xx_wdt_device.queue && ticks) {
  82                 bcm963xx_wdt_device.timer.expires = jiffies + BCM963XX_INTERVAL;
  83                 add_timer(&bcm963xx_wdt_device.timer);
  84         }
  85         else {
  86                 complete(&bcm963xx_wdt_device.stop);
  87         }
  88 }
  89
  90 static void bcm963xx_wdt_reset(void)
  91 {
  92         ticks = bcm963xx_wdt_device.default_ticks;
  93 }
  94
  95 static void bcm963xx_wdt_start(void)
  96 {
  97         if (!bcm963xx_wdt_device.queue) {
  98                 bcm963xx_wdt_device.queue;
  99                 /* Enable the watchdog by writing 0xff00 ,then 0x00ff to the control register */
 100                 WDT->wdt_ctl = 0xff00;
 101                 WDT->wdt_ctl = 0x00ff;
 102                 bcm963xx_wdt_device.timer.expires = jiffies + BCM963XX_INTERVAL;
 103                 add_timer(&bcm963xx_wdt_device.timer);
 104         }
 105         bcm963xx_wdt_device.running++;
 106 }
 107
 108 static int bcm963xx_wdt_stop(void)
 109 {
 110         if (bcm963xx_wdt_device.running)
 111                 bcm963xx_wdt_device.running = 0;
 112
 113         ticks = bcm963xx_wdt_device.default_ticks;
 114
 115         /* Stop the watchdog by writing 0xee00 then 0x00ee to the control register */
 116         WDT->wdt_ctl = 0xee00;
 117         WDT->wdt_ctl = 0x00ee;
 118
 119         return -EIO;
 120 }
 121
 122 static int bcm963xx_wdt_open(struct inode *inode, struct file *file)
 123 {
 124         if (test_and_set_bit(0, &bcm963xx_wdt_device.inuse))
 125                 return -EBUSY;
 126         return nonseekable_open(inode, file);
 127 }
 128
 129 static int bcm963xx_wdt_release(struct inode *inode, struct file *file)
 130 {
 131         clear_bit(0, &bcm963xx_wdt_device.inuse);
 132         return 0;
 133 }
 134
 135 static int bcm963xx_wdt_ioctl(struct inode *inode, struct file *file,
 136                                 unsigned int cmd, unsigned long arg)
 137 {
 138         void __user *argp = (void __user *)arg;
 139         unsigned int value;
 140
 141         static struct watchdog_info ident = {
 142                 .options = WDIOF_CARDRESET,
 143                 .identity = "BCM963xx WDT",
 144         };
 145
 146         switch (cmd) {
 147                 case WDIOC_KEEPALIVE:
 148                         bcm963xx_wdt_reset();
 149                         break;
 150                 case WDIOC_GETSTATUS:
 151                         /* Reading from the control register will return the current value */
 152                         value = WDT->wdt_ctl;
 153                         if ( copy_to_user(argp, &value, sizeof(int)) )
 154                                 return -EFAULT;
 155                         break;
 156                 case WDIOC_GETSUPPORT:
 157                         if ( copy_to_user(argp, &ident, sizeof(ident)) )
 158                                 return -EFAULT;
 159                         break;
 160                 case WDIOC_SETOPTIONS:
 161                         if ( copy_from_user(&value, argp, sizeof(int)) )
 162                                 return -EFAULT;
 163                         switch(value) {
 164                                 case WDIOS_ENABLECARD:
 165                                         bcm963xx_wdt_start();
 166                                         break;
 167                                 case WDIOS_DISABLECARD:
 168                                         bcm963xx_wdt_stop();
 169                                         break;
 170                                 default:
 171                                         return -EINVAL;
 172                         }
 173                         break;
 174                 default:
 175                         return -ENOTTY;
 176         }
 177         return 0;
 178 }
 179
 180 static int bcm963xx_wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 181 {
 182         if (!count)
 183                 return -EIO;
 184         bcm963xx_wdt_reset();
 185         return count;
 186 }
 187
 188 static const struct file_operations bcm963xx_wdt_fops = {
 189         .owner          = THIS_MODULE,
 190         .llseek         = no_llseek,
 191         .write          = bcm963xx_wdt_write,
 192         .ioctl          = bcm963xx_wdt_ioctl,
 193         .open           = bcm963xx_wdt_open,
 194         .release        = bcm963xx_wdt_release,
 195 };
 196
 197 static struct miscdevice bcm963xx_wdt_miscdev = {
 198         .minor  = WATCHDOG_MINOR,
 199         .name   = "watchdog",
 200         .fops   = &bcm963xx_wdt_fops,
 201 };
 202
 203 static void __exit bcm963xx_wdt_exit(void)
 204 {
 205         if (bcm963xx_wdt_device.queue ){
 206                 bcm963xx_wdt_device.queue = 0;
 207                 wait_for_completion(&bcm963xx_wdt_device.stop);
 208         }
 209         misc_deregister(&bcm963xx_wdt_miscdev);
 210 }
 211
 212 static int __init bcm963xx_wdt_init(void)
 213 {
 214         int ret = 0;
 215
 216         printk("Broadcom BCM963xx Watchdog timer\n");
 217
 218         ret = misc_register(&bcm963xx_wdt_miscdev);
 219         if (ret) {
 220                 printk(KERN_CRIT "Cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, ret);
 221                 return ret;
 222         }
 223         init_completion(&bcm963xx_wdt_device.stop);
 224         bcm963xx_wdt_device.queue = 0;
 225
 226         clear_bit(0, &bcm963xx_wdt_device.inuse);
 227
 228         init_timer(&bcm963xx_wdt_device.timer);
 229         bcm963xx_wdt_device.timer.function = bcm963xx_wdt_trigger;
 230         bcm963xx_wdt_device.timer.data = 0;
 231
 232         bcm963xx_wdt_device.default_ticks = ticks;
 233         return ret;
 234 }
 235
 236
 237 module_init(bcm963xx_wdt_init);
 238 module_exit(bcm963xx_wdt_exit);
 239
 240 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 241 MODULE_DESCRIPTION("Broadcom BCM963xx Watchdog driver");
 242 MODULE_LICENSE("GPL");