drivers/sbus/char/riowatchdog.c

   1 /* $Id: riowatchdog.c,v 1.3.2.2 2002/01/23 18:48:02 davem Exp $
   2  * riowatchdog.c - driver for hw watchdog inside Super I/O of RIO
   3  *
   4  * Copyright (C) 2001 David S. Miller (davem@redhat.com)
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/module.h>
   9 #include <linux/types.h>
  10 #include <linux/fs.h>
  11 #include <linux/errno.h>
  12 #include <linux/init.h>
  13 #include <linux/miscdevice.h>
  14
  15 #include <asm/io.h>
  16 #include <asm/ebus.h>
  17 #include <asm/bbc.h>
  18 #include <asm/oplib.h>
  19 #include <asm/uaccess.h>
  20
  21 #include <asm/watchdog.h>
  22
  23 /* RIO uses the NatSemi Super I/O power management logical device
  24  * as its' watchdog.
  25  *
  26  * When the watchdog triggers, it asserts a line to the BBC (Boot Bus
  27  * Controller) of the machine.  The BBC can only be configured to
  28  * trigger a power-on reset when the signal is asserted.  The BBC
  29  * can be configured to ignore the signal entirely as well.
  30  *
  31  * The only Super I/O device register we care about is at index
  32  * 0x05 (WDTO_INDEX) which is the watchdog time-out in minutes (1-255).
  33  * If set to zero, this disables the watchdog.  When set, the system
  34  * must periodically (before watchdog expires) clear (set to zero) and
  35  * re-set the watchdog else it will trigger.
  36  *
  37  * There are two other indexed watchdog registers inside this Super I/O
  38  * logical device, but they are unused.  The first, at index 0x06 is
  39  * the watchdog control and can be used to make the watchdog timer re-set
  40  * when the PS/2 mouse or serial lines show activity.  The second, at
  41  * index 0x07 is merely a sampling of the line from the watchdog to the
  42  * BBC.
  43  *
  44  * The watchdog device generates no interrupts.
  45  */
  46
  47 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  48 MODULE_DESCRIPTION("Hardware watchdog driver for Sun RIO");
  49 MODULE_SUPPORTED_DEVICE("watchdog");
  50 MODULE_LICENSE("GPL");
  51
  52 #define RIOWD_NAME      "pmc"
  53 #define RIOWD_MINOR     215
  54
  55 static DEFINE_SPINLOCK(riowd_lock);
  56
  57 static void __iomem *bbc_regs;
  58 static void __iomem *riowd_regs;
  59 #define WDTO_INDEX      0x05
  60
  61 static int riowd_timeout = 1;           /* in minutes */
  62 module_param(riowd_timeout, int, 0);
  63 MODULE_PARM_DESC(riowd_timeout, "Watchdog timeout in minutes");
  64
  65 #if 0 /* Currently unused. */
  66 static u8 riowd_readreg(int index)
  67 {
  68         unsigned long flags;
  69         u8 ret;
  70
  71         spin_lock_irqsave(&riowd_lock, flags);
  72         writeb(index, riowd_regs + 0);
  73         ret = readb(riowd_regs + 1);
  74         spin_unlock_irqrestore(&riowd_lock, flags);
  75
  76         return ret;
  77 }
  78 #endif
  79
  80 static void riowd_writereg(u8 val, int index)
  81 {
  82         unsigned long flags;
  83
  84         spin_lock_irqsave(&riowd_lock, flags);
  85         writeb(index, riowd_regs + 0);
  86         writeb(val, riowd_regs + 1);
  87         spin_unlock_irqrestore(&riowd_lock, flags);
  88 }
  89
  90 static void riowd_pingtimer(void)
  91 {
  92         riowd_writereg(riowd_timeout, WDTO_INDEX);
  93 }
  94
  95 static void riowd_stoptimer(void)
  96 {
  97         u8 val;
  98
  99         riowd_writereg(0, WDTO_INDEX);
 100
 101         val = readb(bbc_regs + BBC_WDACTION);
 102         val &= ~BBC_WDACTION_RST;
 103         writeb(val, bbc_regs + BBC_WDACTION);
 104 }
 105
 106 static void riowd_starttimer(void)
 107 {
 108         u8 val;
 109
 110         riowd_writereg(riowd_timeout, WDTO_INDEX);
 111
 112         val = readb(bbc_regs + BBC_WDACTION);
 113         val |= BBC_WDACTION_RST;
 114         writeb(val, bbc_regs + BBC_WDACTION);
 115 }
 116
 117 static int riowd_open(struct inode *inode, struct file *filp)
 118 {
 119         nonseekable_open(inode, filp);
 120         return 0;
 121 }
 122
 123 static int riowd_release(struct inode *inode, struct file *filp)
 124 {
 125         return 0;
 126 }
 127
 128 static int riowd_ioctl(struct inode *inode, struct file *filp,
 129                        unsigned int cmd, unsigned long arg)
 130 {
 131         static struct watchdog_info info = {
 132                 WDIOF_SETTIMEOUT, 0, "Natl. Semiconductor PC97317"
 133         };
 134         void __user *argp = (void __user *)arg;
 135         unsigned int options;
 136         int new_margin;
 137
 138         switch (cmd) {
 139         case WDIOC_GETSUPPORT:
 140                 if (copy_to_user(argp, &info, sizeof(info)))
 141                         return -EFAULT;
 142                 break;
 143
 144         case WDIOC_GETSTATUS:
 145         case WDIOC_GETBOOTSTATUS:
 146                 if (put_user(0, (int __user *)argp))
 147                         return -EFAULT;
 148                 break;
 149
 150         case WDIOC_KEEPALIVE:
 151                 riowd_pingtimer();
 152                 break;
 153
 154         case WDIOC_SETOPTIONS:
 155                 if (copy_from_user(&options, argp, sizeof(options)))
 156                         return -EFAULT;
 157
 158                 if (options & WDIOS_DISABLECARD)
 159                         riowd_stoptimer();
 160                 else if (options & WDIOS_ENABLECARD)
 161                         riowd_starttimer();
 162                 else
 163                         return -EINVAL;
 164
 165                 break;
 166
 167         case WDIOC_SETTIMEOUT:
 168                 if (get_user(new_margin, (int __user *)argp))
 169                         return -EFAULT;
 170                 if ((new_margin < 60) || (new_margin > (255 * 60)))
 171                     return -EINVAL;
 172                 riowd_timeout = (new_margin + 59) / 60;
 173                 riowd_pingtimer();
 174                 /* Fall */
 175
 176         case WDIOC_GETTIMEOUT:
 177                 return put_user(riowd_timeout * 60, (int __user *)argp);
 178
 179         default:
 180                 return -EINVAL;
 181         };
 182
 183         return 0;
 184 }
 185
 186 static ssize_t riowd_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 187 {
 188         if (count) {
 189                 riowd_pingtimer();
 190                 return 1;
 191         }
 192
 193         return 0;
 194 }
 195
 196 static const struct file_operations riowd_fops = {
 197         .owner =        THIS_MODULE,
 198         .ioctl =        riowd_ioctl,
 199         .open =         riowd_open,
 200         .write =        riowd_write,
 201         .release =      riowd_release,
 202 };
 203
 204 static struct miscdevice riowd_miscdev = { RIOWD_MINOR, RIOWD_NAME, &riowd_fops };
 205
 206 static int __init riowd_bbc_init(void)
 207 {
 208         struct  linux_ebus *ebus = NULL;
 209         struct  linux_ebus_device *edev = NULL;
 210         u8 val;
 211
 212         for_each_ebus(ebus) {
 213                 for_each_ebusdev(edev, ebus) {
 214                         if (!strcmp(edev->ofdev.node->name, "bbc"))
 215                                 goto found_bbc;
 216                 }
 217         }
 218
 219 found_bbc:
 220         if (!edev)
 221                 return -ENODEV;
 222         bbc_regs = ioremap(edev->resource[0].start, BBC_REGS_SIZE);
 223         if (!bbc_regs)
 224                 return -ENODEV;
 225
 226         /* Turn it off. */
 227         val = readb(bbc_regs + BBC_WDACTION);
 228         val &= ~BBC_WDACTION_RST;
 229         writeb(val, bbc_regs + BBC_WDACTION);
 230
 231         return 0;
 232 }
 233
 234 static int __init riowd_init(void)
 235 {
 236         struct  linux_ebus *ebus = NULL;
 237         struct  linux_ebus_device *edev = NULL;
 238
 239         for_each_ebus(ebus) {
 240                 for_each_ebusdev(edev, ebus) {
 241                         if (!strcmp(edev->ofdev.node->name, RIOWD_NAME))
 242                                 goto ebus_done;
 243                 }
 244         }
 245
 246 ebus_done:
 247         if (!edev)
 248                 goto fail;
 249
 250         riowd_regs = ioremap(edev->resource[0].start, 2);
 251         if (riowd_regs == NULL) {
 252                 printk(KERN_ERR "pmc: Cannot map registers.\n");
 253                 return -ENODEV;
 254         }
 255
 256         if (riowd_bbc_init()) {
 257                 printk(KERN_ERR "pmc: Failure initializing BBC config.\n");
 258                 goto fail;
 259         }
 260
 261         if (misc_register(&riowd_miscdev)) {
 262                 printk(KERN_ERR "pmc: Cannot register watchdog misc device.\n");
 263                 goto fail;
 264         }
 265
 266         printk(KERN_INFO "pmc: Hardware watchdog [%i minutes], "
 267                "regs at %p\n", riowd_timeout, riowd_regs);
 268
 269         return 0;
 270
 271 fail:
 272         if (riowd_regs) {
 273                 iounmap(riowd_regs);
 274                 riowd_regs = NULL;
 275         }
 276         if (bbc_regs) {
 277                 iounmap(bbc_regs);
 278                 bbc_regs = NULL;
 279         }
 280         return -ENODEV;
 281 }
 282
 283 static void __exit riowd_cleanup(void)
 284 {
 285         misc_deregister(&riowd_miscdev);
 286         iounmap(riowd_regs);
 287         riowd_regs = NULL;
 288         iounmap(bbc_regs);
 289         bbc_regs = NULL;
 290 }
 291
 292 module_init(riowd_init);
 293 module_exit(riowd_cleanup);