drivers/watchdog/rc32434_wdt.c

   1 /*
   2  *  IDT Interprise 79RC32434 watchdog driver
   3  *
   4  *  Copyright (C) 2006, Ondrej Zajicek <santiago@crfreenet.org>
   5  *  Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
   6  *
   7  *  based on
   8  *  SoftDog 0.05:       A Software Watchdog Device
   9  *
  10  *  (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
  11  *                                      All Rights Reserved.
  12  *
  13  *  This program is free software; you can redistribute it and/or
  14  *  modify it under the terms of the GNU General Public License
  15  *  as published by the Free Software Foundation; either version
  16  *  2 of the License, or (at your option) any later version.
  17  *
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/types.h>
  22 #include <linux/kernel.h>
  23 #include <linux/fs.h>
  24 #include <linux/mm.h>
  25 #include <linux/miscdevice.h>
  26 #include <linux/watchdog.h>
  27 #include <linux/reboot.h>
  28 #include <linux/smp_lock.h>
  29 #include <linux/init.h>
  30 #include <linux/platform_device.h>
  31 #include <linux/uaccess.h>
  32
  33 #include <asm/bootinfo.h>
  34 #include <asm/time.h>
  35 #include <asm/mach-rc32434/integ.h>
  36
  37 #define VERSION "0.4"
  38
  39 static struct {
  40         unsigned long inuse;
  41 } rc32434_wdt_device;
  42
  43 static struct integ __iomem *wdt_reg;
  44
  45 static int expect_close;
  46
  47 /* Board internal clock speed in Hz,
  48  * the watchdog timer ticks at. */
  49 extern unsigned int idt_cpu_freq;
  50
  51 /* translate wtcompare value to seconds and vice versa */
  52 #define WTCOMP2SEC(x)   (x / idt_cpu_freq)
  53 #define SEC2WTCOMP(x)   (x * idt_cpu_freq)
  54
  55 /* Use a default timeout of 20s. This should be
  56  * safe for CPU clock speeds up to 400MHz, as
  57  * ((2 ^ 32) - 1) / (400MHz / 2) = 21s.  */
  58 #define WATCHDOG_TIMEOUT 20
  59
  60 static int timeout = WATCHDOG_TIMEOUT;
  61
  62 static int nowayout = WATCHDOG_NOWAYOUT;
  63 module_param(nowayout, int, 0);
  64 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  65         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  66
  67 /* apply or and nand masks to data read from addr and write back */
  68 #define SET_BITS(addr, or, nand) \
  69         writel((readl(&addr) | or) & ~nand, &addr)
  70
  71 static void rc32434_wdt_start(void)
  72 {
  73         u32 or, nand;
  74
  75         /* zero the counter before enabling */
  76         writel(0, &wdt_reg->wtcount);
  77
  78         /* don't generate a non-maskable interrupt,
  79          * do a warm reset instead */
  80         nand = 1 << RC32434_ERR_WNE;
  81         or = 1 << RC32434_ERR_WRE;
  82
  83         /* reset the ERRCS timeout bit in case it's set */
  84         nand |= 1 << RC32434_ERR_WTO;
  85
  86         SET_BITS(wdt_reg->errcs, or, nand);
  87
  88         /* reset WTC timeout bit and enable WDT */
  89         nand = 1 << RC32434_WTC_TO;
  90         or = 1 << RC32434_WTC_EN;
  91
  92         SET_BITS(wdt_reg->wtc, or, nand);
  93 }
  94
  95 static void rc32434_wdt_stop(void)
  96 {
  97         /* Disable WDT */
  98         SET_BITS(wdt_reg->wtc, 0, 1 << RC32434_WTC_EN);
  99 }
 100
 101 static int rc32434_wdt_set(int new_timeout)
 102 {
 103         int max_to = WTCOMP2SEC((u32)-1);
 104
 105         if (new_timeout < 0 || new_timeout > max_to) {
 106                 printk(KERN_ERR KBUILD_MODNAME
 107                         ": timeout value must be between 0 and %d",
 108                         max_to);
 109                 return -EINVAL;
 110         }
 111         timeout = new_timeout;
 112         writel(SEC2WTCOMP(timeout), &wdt_reg->wtcompare);
 113
 114         return 0;
 115 }
 116
 117 static void rc32434_wdt_ping(void)
 118 {
 119         writel(0, &wdt_reg->wtcount);
 120 }
 121
 122 static int rc32434_wdt_open(struct inode *inode, struct file *file)
 123 {
 124         if (test_and_set_bit(0, &rc32434_wdt_device.inuse))
 125                 return -EBUSY;
 126
 127         if (nowayout)
 128                 __module_get(THIS_MODULE);
 129
 130         rc32434_wdt_start();
 131         rc32434_wdt_ping();
 132
 133         return nonseekable_open(inode, file);
 134 }
 135
 136 static int rc32434_wdt_release(struct inode *inode, struct file *file)
 137 {
 138         if (expect_close == 42) {
 139                 rc32434_wdt_stop();
 140                 printk(KERN_INFO KBUILD_MODNAME ": disabling watchdog timer\n");
 141                 module_put(THIS_MODULE);
 142         } else {
 143                 printk(KERN_CRIT KBUILD_MODNAME
 144                         ": device closed unexpectedly. WDT will not stop !\n");
 145                 rc32434_wdt_ping();
 146         }
 147         clear_bit(0, &rc32434_wdt_device.inuse);
 148         return 0;
 149 }
 150
 151 static ssize_t rc32434_wdt_write(struct file *file, const char *data,
 152                                 size_t len, loff_t *ppos)
 153 {
 154         if (len) {
 155                 if (!nowayout) {
 156                         size_t i;
 157
 158                         /* In case it was set long ago */
 159                         expect_close = 0;
 160
 161                         for (i = 0; i != len; i++) {
 162                                 char c;
 163                                 if (get_user(c, data + i))
 164                                         return -EFAULT;
 165                                 if (c == 'V')
 166                                         expect_close = 42;
 167                         }
 168                 }
 169                 rc32434_wdt_ping();
 170                 return len;
 171         }
 172         return 0;
 173 }
 174
 175 static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd,
 176                                 unsigned long arg)
 177 {
 178         void __user *argp = (void __user *)arg;
 179         int new_timeout;
 180         unsigned int value;
 181         static struct watchdog_info ident = {
 182                 .options =              WDIOF_SETTIMEOUT |
 183                                         WDIOF_KEEPALIVEPING |
 184                                         WDIOF_MAGICCLOSE,
 185                 .identity =             "RC32434_WDT Watchdog",
 186         };
 187         switch (cmd) {
 188         case WDIOC_KEEPALIVE:
 189                 rc32434_wdt_ping();
 190                 break;
 191         case WDIOC_GETSTATUS:
 192         case WDIOC_GETBOOTSTATUS:
 193                 value = 0;
 194                 if (copy_to_user(argp, &value, sizeof(int)))
 195                         return -EFAULT;
 196                 break;
 197         case WDIOC_GETSUPPORT:
 198                 if (copy_to_user(argp, &ident, sizeof(ident)))
 199                         return -EFAULT;
 200                 break;
 201         case WDIOC_SETOPTIONS:
 202                 if (copy_from_user(&value, argp, sizeof(int)))
 203                         return -EFAULT;
 204                 switch (value) {
 205                 case WDIOS_ENABLECARD:
 206                         rc32434_wdt_start();
 207                         break;
 208                 case WDIOS_DISABLECARD:
 209                         rc32434_wdt_stop();
 210                         break;
 211                 default:
 212                         return -EINVAL;
 213                 }
 214                 break;
 215         case WDIOC_SETTIMEOUT:
 216                 if (copy_from_user(&new_timeout, argp, sizeof(int)))
 217                         return -EFAULT;
 218                 if (rc32434_wdt_set(new_timeout))
 219                         return -EINVAL;
 220                 /* Fall through */
 221         case WDIOC_GETTIMEOUT:
 222                 return copy_to_user(argp, &timeout, sizeof(int));
 223         default:
 224                 return -ENOTTY;
 225         }
 226
 227         return 0;
 228 }
 229
 230 static struct file_operations rc32434_wdt_fops = {
 231         .owner          = THIS_MODULE,
 232         .llseek         = no_llseek,
 233         .write          = rc32434_wdt_write,
 234         .unlocked_ioctl = rc32434_wdt_ioctl,
 235         .open           = rc32434_wdt_open,
 236         .release        = rc32434_wdt_release,
 237 };
 238
 239 static struct miscdevice rc32434_wdt_miscdev = {
 240         .minor  = WATCHDOG_MINOR,
 241         .name   = "watchdog",
 242         .fops   = &rc32434_wdt_fops,
 243 };
 244
 245 static char banner[] __devinitdata = KERN_INFO KBUILD_MODNAME
 246                 ": Watchdog Timer version " VERSION ", timer margin: %d sec\n";
 247
 248 static int __devinit rc32434_wdt_probe(struct platform_device *pdev)
 249 {
 250         int ret;
 251         struct resource *r;
 252
 253         r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rb532_wdt_res");
 254         if (!r) {
 255                 printk(KERN_ERR KBUILD_MODNAME
 256                         "failed to retrieve resources\n");
 257                 return -ENODEV;
 258         }
 259
 260         wdt_reg = ioremap_nocache(r->start, r->end - r->start);
 261         if (!wdt_reg) {
 262                 printk(KERN_ERR KBUILD_MODNAME
 263                         "failed to remap I/O resources\n");
 264                 return -ENXIO;
 265         }
 266
 267         ret = misc_register(&rc32434_wdt_miscdev);
 268         if (ret < 0) {
 269                 printk(KERN_ERR KBUILD_MODNAME
 270                         "failed to register watchdog device\n");
 271                 goto unmap;
 272         }
 273
 274         printk(banner, timeout);
 275
 276         return 0;
 277
 278 unmap:
 279         iounmap(wdt_reg);
 280         return ret;
 281 }
 282
 283 static int __devexit rc32434_wdt_remove(struct platform_device *pdev)
 284 {
 285         misc_deregister(&rc32434_wdt_miscdev);
 286         iounmap(wdt_reg);
 287         return 0;
 288 }
 289
 290 static struct platform_driver rc32434_wdt = {
 291         .probe  = rc32434_wdt_probe,
 292         .remove = __devexit_p(rc32434_wdt_remove),
 293         .driver = {
 294                 .name = "rc32434_wdt",
 295         }
 296 };
 297
 298 static int __init rc32434_wdt_init(void)
 299 {
 300         return platform_driver_register(&rc32434_wdt);
 301 }
 302
 303 static void __exit rc32434_wdt_exit(void)
 304 {
 305         platform_driver_unregister(&rc32434_wdt);
 306 }
 307
 308 module_init(rc32434_wdt_init);
 309 module_exit(rc32434_wdt_exit);
 310
 311 MODULE_AUTHOR("Ondrej Zajicek <santiago@crfreenet.org>,"
 312                 "Florian Fainelli <florian@openwrt.org>");
 313 MODULE_DESCRIPTION("Driver for the IDT RC32434 SoC watchdog");
 314 MODULE_LICENSE("GPL");
 315 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);