drivers/char/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/config.h>
  13 #include <linux/fs.h>
  14 #include <linux/init.h>
  15 #include <linux/kernel.h>
  16 #include <linux/miscdevice.h>
  17 #include <linux/module.h>
  18 #include <linux/watchdog.h>
  19 #include <asm/8xx_immap.h>
  20 #include <asm/uaccess.h>
  21 #include <asm/io.h>
  22 #include <syslib/m8xx_wdt.h>
  23
  24 static unsigned long wdt_opened;
  25 static int wdt_status;
  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
  37         printk(KERN_NOTICE "mpc8xx_wdt: keep-alive handler deactivated\n");
  38 }
  39
  40 static void mpc8xx_wdt_handler_enable(void)
  41 {
  42         volatile uint __iomem *piscr;
  43         piscr = (uint *)&((immap_t*)IMAP_ADDR)->im_sit.sit_piscr;
  44
  45         if (!m8xx_has_internal_rtc)
  46                 m8xx_wdt_install_timer();
  47         else
  48                 out_be32(piscr, in_be32(piscr) | PISCR_PIE | PISCR_PTE);
  49
  50         printk(KERN_NOTICE "mpc8xx_wdt: keep-alive handler activated\n");
  51 }
  52
  53 static int mpc8xx_wdt_open(struct inode *inode, struct file *file)
  54 {
  55         if (test_and_set_bit(0, &wdt_opened))
  56                 return -EBUSY;
  57
  58         m8xx_wdt_reset();
  59         mpc8xx_wdt_handler_disable();
  60
  61         return 0;
  62 }
  63
  64 static int mpc8xx_wdt_release(struct inode *inode, struct file *file)
  65 {
  66         m8xx_wdt_reset();
  67
  68 #if !defined(CONFIG_WATCHDOG_NOWAYOUT)
  69         mpc8xx_wdt_handler_enable();
  70 #endif
  71
  72         clear_bit(0, &wdt_opened);
  73
  74         return 0;
  75 }
  76
  77 static ssize_t mpc8xx_wdt_write(struct file *file, const char *data, size_t len,
  78                                 loff_t * ppos)
  79 {
  80         if (len)
  81                 m8xx_wdt_reset();
  82
  83         return len;
  84 }
  85
  86 static int mpc8xx_wdt_ioctl(struct inode *inode, struct file *file,
  87                             unsigned int cmd, unsigned long arg)
  88 {
  89         int timeout;
  90         static struct watchdog_info info = {
  91                 .options = WDIOF_KEEPALIVEPING,
  92                 .firmware_version = 0,
  93                 .identity = "MPC8xx watchdog",
  94         };
  95
  96         switch (cmd) {
  97         case WDIOC_GETSUPPORT:
  98                 if (copy_to_user((void *)arg, &info, sizeof(info)))
  99                         return -EFAULT;
 100                 break;
 101
 102         case WDIOC_GETSTATUS:
 103         case WDIOC_GETBOOTSTATUS:
 104                 if (put_user(wdt_status, (int *)arg))
 105                         return -EFAULT;
 106                 wdt_status &= ~WDIOF_KEEPALIVEPING;
 107                 break;
 108
 109         case WDIOC_GETTEMP:
 110                 return -EOPNOTSUPP;
 111
 112         case WDIOC_SETOPTIONS:
 113                 return -EOPNOTSUPP;
 114
 115         case WDIOC_KEEPALIVE:
 116                 m8xx_wdt_reset();
 117                 wdt_status |= WDIOF_KEEPALIVEPING;
 118                 break;
 119
 120         case WDIOC_SETTIMEOUT:
 121                 return -EOPNOTSUPP;
 122
 123         case WDIOC_GETTIMEOUT:
 124                 timeout = m8xx_wdt_get_timeout();
 125                 if (put_user(timeout, (int *)arg))
 126                         return -EFAULT;
 127                 break;
 128
 129         default:
 130                 return -ENOIOCTLCMD;
 131         }
 132
 133         return 0;
 134 }
 135
 136 static struct file_operations mpc8xx_wdt_fops = {
 137         .owner = THIS_MODULE,
 138         .llseek = no_llseek,
 139         .write = mpc8xx_wdt_write,
 140         .ioctl = mpc8xx_wdt_ioctl,
 141         .open = mpc8xx_wdt_open,
 142         .release = mpc8xx_wdt_release,
 143 };
 144
 145 static struct miscdevice mpc8xx_wdt_miscdev = {
 146         .minor = WATCHDOG_MINOR,
 147         .name = "watchdog",
 148         .fops = &mpc8xx_wdt_fops,
 149 };
 150
 151 static int __init mpc8xx_wdt_init(void)
 152 {
 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);