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