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