target/linux/aruba-2.6/files/drivers/char/watchdog/wdt_merlot.c

   1 #include <linux/autoconf.h>
   2 #include <linux/module.h>
   3 #include <linux/types.h>
   4 #include <linux/miscdevice.h>
   5 #include <linux/watchdog.h>
   6 #include <linux/fs.h>
   7 #include <linux/jiffies.h>
   8 #include <linux/timer.h>
   9
  10 #include <asm/io.h>
  11 #include <asm/uaccess.h>
  12 #include <asm/system.h>
  13 #include <asm/bootinfo.h>
  14
  15 extern unsigned long mips_machtype;
  16
  17 static unsigned long wdt_is_open;
  18 static struct timer_list wdt_timer;
  19
  20 static void wdt_merlot_refresh(void)
  21 {
  22     volatile __u32 *wdt;
  23     switch (mips_machtype) {
  24     case MACH_ARUBA_AP70:
  25         wdt = (__u32 *) 0xb8030034;
  26         *wdt = 0x10000000;
  27         break;
  28     default:
  29         wdt = (__u32 *) 0xbc00300c;
  30         *wdt = 0x40000000;
  31         break;
  32     }
  33 }
  34
  35 static void wdt_merlot_timer_fn(unsigned long data)
  36 {
  37     wdt_merlot_refresh();
  38     if (!test_bit(1, &wdt_is_open))
  39         mod_timer(&wdt_timer, jiffies + HZ);
  40 }
  41
  42 static int wdt_merlot_setup_timer(void)
  43 {
  44
  45     init_timer(&wdt_timer);
  46     wdt_timer.function = wdt_merlot_timer_fn;
  47     wdt_timer.data = 0;
  48     wdt_timer.expires = jiffies + HZ;
  49     add_timer(&wdt_timer);
  50     return 0;
  51 }
  52
  53 static int wdt_open(struct inode *inode, struct file *file)
  54 {
  55     if (test_and_set_bit(0, &wdt_is_open))
  56         return -EBUSY;
  57     set_bit(1, &wdt_is_open);
  58     return nonseekable_open(inode, file);
  59 }
  60
  61 static ssize_t wdt_write(struct file *file, const char __user * buf, size_t count, loff_t * ppos)
  62 {
  63     if (count)  /* something was written */
  64         wdt_merlot_refresh();
  65     return count;
  66 }
  67
  68 static int wdt_release(struct inode *inode, struct file *file)
  69 {
  70     clear_bit(0, &wdt_is_open);
  71     return 0;
  72 }
  73
  74 static struct file_operations wdt_fops = {
  75     .owner = THIS_MODULE,
  76     .llseek = no_llseek,
  77     .write = wdt_write,
  78     .open = wdt_open,
  79     .release = wdt_release,
  80 };
  81
  82 static struct miscdevice wdt_miscdev = {
  83     .minor = WATCHDOG_MINOR,
  84     .name = "watchdog",
  85     .fops = &wdt_fops,
  86 };
  87
  88 static void __exit wdt_exit(void)
  89 {
  90     misc_deregister(&wdt_miscdev);
  91 }
  92
  93 static int __init wdt_init(void)
  94 {
  95     int ret;
  96     ret = misc_register(&wdt_miscdev);
  97     if (ret) {
  98         printk(KERN_ERR
  99                "wdt: cannot register miscdev on minor=%d (err=%d)\n",
 100                WATCHDOG_MINOR, ret);
 101         misc_deregister(&wdt_miscdev);
 102         goto out;
 103     }
 104     printk("wdt: registered with refresh\n");
 105     wdt_merlot_refresh();
 106     wdt_merlot_setup_timer();
 107   out:
 108     return ret;
 109 }
 110
 111 module_init(wdt_init);
 112 module_exit(wdt_exit);