drivers/watchdog/mpc8xx_wdt.c

   1 /*
   2  * mpc8xx_wdt.c - MPC8xx watchdog userspace interface
   3  *
   4  * Author: Florian Schirmer <jolt@tuxbox.org>
   5  *
   6  * 2002 (c) Florian Schirmer <jolt@tuxbox.org> This file is licensed under
   7  * the terms of the GNU General Public License version 2. This program
   8  * is licensed "as is" without any warranty of any kind, whether express
   9  * or implied.
  10  */
  11
  12 #include <linux/fs.h>
  13 #include <linux/init.h>
  14 #include <linux/kernel.h>
  15 #include <linux/miscdevice.h>
  16 #include <linux/module.h>
  17 #include <linux/watchdog.h>
  18 #include <asm/8xx_immap.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/io.h>
  21 #include <syslib/m8xx_wdt.h>
  22
  23 static unsigned long wdt_opened;
  24 static int wdt_status;
  25 static spinlock_t wdt_lock;
  26
  27 static void mpc8xx_wdt_handler_disable(void)
  28 {
  29         volatile uint __iomem *piscr;
  30         piscr = (uint *)&((immap_t *)IMAP_ADDR)->im_sit.sit_piscr;
  31
  32         if (!m8xx_has_internal_rtc)
  33                 m8xx_wdt_stop_timer();
  34         else
  35                 out_be32(piscr, in_be32(piscr) & ~(PISCR_PIE | PISCR_PTE));
  36         printk(KERN_NOTICE "mpc8xx_wdt: keep-alive handler deactivated\n");
  37 }
  38
  39 static void mpc8xx_wdt_handler_enable(void)
  40 {
  41         volatile uint __iomem *piscr;
  42         piscr = (uint *)&((immap_t *)IMAP_ADDR)->im_sit.sit_piscr;
  43
  44         if (!m8xx_has_internal_rtc)
  45                 m8xx_wdt_install_timer();
  46         else
  47                 out_be32(piscr, in_be32(piscr) | PISCR_PIE | PISCR_PTE);
  48         printk(KERN_NOTICE "mpc8xx_wdt: keep-alive handler activated\n");
  49 }
  50
  51 static int mpc8xx_wdt_open(struct inode *inode, struct file *file)
  52 {
  53         if (test_and_set_bit(0, &wdt_opened))
  54                 return -EBUSY;
  55         m8xx_wdt_reset();
  56         mpc8xx_wdt_handler_disable();
  57         return nonseekable_open(inode, file);
  58 }
  59
  60 static int mpc8xx_wdt_release(struct inode *inode, struct file *file)
  61 {
  62         m8xx_wdt_reset();
  63 #if !defined(CONFIG_WATCHDOG_NOWAYOUT)
  64         mpc8xx_wdt_handler_enable();
  65 #endif
  66         clear_bit(0, &wdt_opened);
  67         return 0;
  68 }
  69
  70 static ssize_t mpc8xx_wdt_write(struct file *file, const char *data,
  71                                                 size_t len, loff_t *ppos)
  72 {
  73         if (len) {
  74                 spin_lock(&wdt_lock);
  75                 m8xx_wdt_reset();
  76                 spin_unlock(&wdt_lock);
  77         }
  78         return len;
  79 }
  80
  81 static long mpc8xx_wdt_ioctl(struct file *file,
  82                                         unsigned int cmd, unsigned long arg)
  83 {
  84         int timeout;
  85         static struct watchdog_info info = {
  86                 .options = WDIOF_KEEPALIVEPING,
  87                 .firmware_version = 0,
  88                 .identity = "MPC8xx watchdog",
  89         };
  90
  91         switch (cmd) {
  92         case WDIOC_GETSUPPORT:
  93                 if (copy_to_user((void *)arg, &info, sizeof(info)))
  94                         return -EFAULT;
  95                 break;
  96
  97         case WDIOC_GETSTATUS:
  98         case WDIOC_GETBOOTSTATUS:
  99                 if (put_user(wdt_status, (int *)arg))
 100                         return -EFAULT;
 101                 wdt_status &= ~WDIOF_KEEPALIVEPING;
 102                 break;
 103
 104         case WDIOC_GETTEMP:
 105                 return -EOPNOTSUPP;
 106
 107         case WDIOC_SETOPTIONS:
 108                 return -EOPNOTSUPP;
 109
 110         case WDIOC_KEEPALIVE:
 111                 spin_lock(&wdt_lock);
 112                 m8xx_wdt_reset();
 113                 wdt_status |= WDIOF_KEEPALIVEPING;
 114                 spin_unlock(&wdt_lock);
 115                 break;
 116
 117         case WDIOC_SETTIMEOUT:
 118                 return -EOPNOTSUPP;
 119
 120         case WDIOC_GETTIMEOUT:
 121                 spin_lock(&wdt_lock);
 122                 timeout = m8xx_wdt_get_timeout();
 123                 spin_unlock(&wdt_lock);
 124                 if (put_user(timeout, (int *)arg))
 125                         return -EFAULT;
 126                 break;
 127
 128         default:
 129                 return -ENOTTY;
 130         }
 131
 132         return 0;
 133 }
 134
 135 static const struct file_operations mpc8xx_wdt_fops = {
 136         .owner = THIS_MODULE,
 137         .llseek = no_llseek,
 138         .write = mpc8xx_wdt_write,
 139         .unlocked_ioctl = mpc8xx_wdt_ioctl,
 140         .open = mpc8xx_wdt_open,
 141         .release = mpc8xx_wdt_release,
 142 };
 143
 144 static struct miscdevice mpc8xx_wdt_miscdev = {
 145         .minor = WATCHDOG_MINOR,
 146         .name = "watchdog",
 147         .fops = &mpc8xx_wdt_fops,
 148 };
 149
 150 static int __init mpc8xx_wdt_init(void)
 151 {
 152         spin_lock_init(&wdt_lock);
 153         return misc_register(&mpc8xx_wdt_miscdev);
 154 }
 155
 156 static void __exit mpc8xx_wdt_exit(void)
 157 {
 158         misc_deregister(&mpc8xx_wdt_miscdev);
 159
 160         m8xx_wdt_reset();
 161         mpc8xx_wdt_handler_enable();
 162 }
 163
 164 module_init(mpc8xx_wdt_init);
 165 module_exit(mpc8xx_wdt_exit);
 166
 167 MODULE_AUTHOR("Florian Schirmer <jolt@tuxbox.org>");
 168 MODULE_DESCRIPTION("MPC8xx watchdog driver");
 169 MODULE_LICENSE("GPL");
 170 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);