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/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 <asm/uaccess.h>
  20 #include <asm/io.h>
  21 #include <syslib/m8xx_wdt.h>
  22
  23 static unsigned long wdt_opened;
  24 static int wdt_status;
  25
  26 static void mpc8xx_wdt_handler_disable(void)
  27 {
  28         volatile uint __iomem *piscr;
  29         piscr = (uint *)&((immap_t*)IMAP_ADDR)->im_sit.sit_piscr;
  30
  31         if (!m8xx_has_internal_rtc)
  32                 m8xx_wdt_stop_timer();
  33         else
  34                 out_be32(piscr, in_be32(piscr) & ~(PISCR_PIE | PISCR_PTE));
  35
  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
  49         printk(KERN_NOTICE "mpc8xx_wdt: keep-alive handler activated\n");
  50 }
  51
  52 static int mpc8xx_wdt_open(struct inode *inode, struct file *file)
  53 {
  54         if (test_and_set_bit(0, &wdt_opened))
  55                 return -EBUSY;
  56
  57         m8xx_wdt_reset();
  58         mpc8xx_wdt_handler_disable();
  59
  60         return 0;
  61 }
  62
  63 static int mpc8xx_wdt_release(struct inode *inode, struct file *file)
  64 {
  65         m8xx_wdt_reset();
  66
  67 #if !defined(CONFIG_WATCHDOG_NOWAYOUT)
  68         mpc8xx_wdt_handler_enable();
  69 #endif
  70
  71         clear_bit(0, &wdt_opened);
  72
  73         return 0;
  74 }
  75
  76 static ssize_t mpc8xx_wdt_write(struct file *file, const char *data, size_t len,
  77                                 loff_t * ppos)
  78 {
  79         if (len)
  80                 m8xx_wdt_reset();
  81
  82         return len;
  83 }
  84
  85 static int mpc8xx_wdt_ioctl(struct inode *inode, struct file *file,
  86                             unsigned int cmd, unsigned long arg)
  87 {
  88         int timeout;
  89         static struct watchdog_info info = {
  90                 .options = WDIOF_KEEPALIVEPING,
  91                 .firmware_version = 0,
  92                 .identity = "MPC8xx watchdog",
  93         };
  94
  95         switch (cmd) {
  96         case WDIOC_GETSUPPORT:
  97                 if (copy_to_user((void *)arg, &info, sizeof(info)))
  98                         return -EFAULT;
  99                 break;
 100
 101         case WDIOC_GETSTATUS:
 102         case WDIOC_GETBOOTSTATUS:
 103                 if (put_user(wdt_status, (int *)arg))
 104                         return -EFAULT;
 105                 wdt_status &= ~WDIOF_KEEPALIVEPING;
 106                 break;
 107
 108         case WDIOC_GETTEMP:
 109                 return -EOPNOTSUPP;
 110
 111         case WDIOC_SETOPTIONS:
 112                 return -EOPNOTSUPP;
 113
 114         case WDIOC_KEEPALIVE:
 115                 m8xx_wdt_reset();
 116                 wdt_status |= WDIOF_KEEPALIVEPING;
 117                 break;
 118
 119         case WDIOC_SETTIMEOUT:
 120                 return -EOPNOTSUPP;
 121
 122         case WDIOC_GETTIMEOUT:
 123                 timeout = m8xx_wdt_get_timeout();
 124                 if (put_user(timeout, (int *)arg))
 125                         return -EFAULT;
 126                 break;
 127
 128         default:
 129                 return -ENOIOCTLCMD;
 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         .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         return misc_register(&mpc8xx_wdt_miscdev);
 153 }
 154
 155 static void __exit mpc8xx_wdt_exit(void)
 156 {
 157         misc_deregister(&mpc8xx_wdt_miscdev);
 158
 159         m8xx_wdt_reset();
 160         mpc8xx_wdt_handler_enable();
 161 }
 162
 163 module_init(mpc8xx_wdt_init);
 164 module_exit(mpc8xx_wdt_exit);
 165
 166 MODULE_AUTHOR("Florian Schirmer <jolt@tuxbox.org>");
 167 MODULE_DESCRIPTION("MPC8xx watchdog driver");
 168 MODULE_LICENSE("GPL");
 169 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);