target/linux/ar71xx/files/drivers/watchdog/ar71xx_wdt.c

   1 /*
   2  * Driver for the Atheros AR71xx SoC's built-in hardware watchdog timer.
   3  *
   4  * Copyright (C) 2008 Gabor Juhos <juhosg@openwrt.org>
   5  * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
   6  *
   7  * This driver was based on: drivers/watchdog/ixp4xx_wdt.c
   8  *      Author: Deepak Saxena <dsaxena@plexity.net>
   9  *      Copyright 2004 (c) MontaVista, Software, Inc.
  10  *
  11  * which again was based on sa1100 driver,
  12  *      Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
  13  *
  14  * This program is free software; you can redistribute it and/or modify it
  15  * under the terms of the GNU General Public License version 2 as published
  16  * by the Free Software Foundation.
  17  *
  18  */
  19
  20 #include <linux/bitops.h>
  21 #include <linux/errno.h>
  22 #include <linux/fs.h>
  23 #include <linux/init.h>
  24 #include <linux/kernel.h>
  25 #include <linux/miscdevice.h>
  26 #include <linux/module.h>
  27 #include <linux/moduleparam.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/types.h>
  30 #include <linux/watchdog.h>
  31
  32 #include <asm/mach-ar71xx/ar71xx.h>
  33
  34 #define DRV_NAME        "ar71xx-wdt"
  35 #define DRV_DESC        "Atheros AR71xx hardware watchdog driver"
  36 #define DRV_VERSION     "0.1.0"
  37
  38 #define WDT_TIMEOUT     15      /* seconds */
  39
  40 static int nowayout = WATCHDOG_NOWAYOUT;
  41
  42 #ifdef CONFIG_WATCHDOG_NOWAYOUT
  43 module_param(nowayout, int, 0);
  44 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
  45                            "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  46 #endif
  47
  48 static unsigned long wdt_flags;
  49
  50 #define WDT_FLAGS_BUSY          0
  51 #define WDT_FLAGS_EXPECT_CLOSE  1
  52
  53 static int wdt_timeout = WDT_TIMEOUT;
  54 static int boot_status;
  55 static int max_timeout;
  56
  57 static void inline ar71xx_wdt_keepalive(void)
  58 {
  59         ar71xx_reset_wr(AR71XX_RESET_REG_WDOG, ar71xx_ahb_freq * wdt_timeout);
  60 }
  61
  62 static void inline ar71xx_wdt_enable(void)
  63 {
  64         printk(KERN_DEBUG DRV_NAME ": enabling watchdog timer\n");
  65         ar71xx_wdt_keepalive();
  66         ar71xx_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_FCR);
  67 }
  68
  69 static void inline ar71xx_wdt_disable(void)
  70 {
  71         printk(KERN_DEBUG DRV_NAME ": disabling watchdog timer\n");
  72         ar71xx_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_NONE);
  73 }
  74
  75 static int ar71xx_wdt_set_timeout(int val)
  76 {
  77         if (val < 1 || val > max_timeout)
  78                 return -EINVAL;
  79
  80         wdt_timeout = val;
  81         ar71xx_wdt_keepalive();
  82
  83         printk(KERN_DEBUG DRV_NAME ": timeout=%d secs\n", wdt_timeout);
  84
  85         return 0;
  86 }
  87
  88 static int ar71xx_wdt_open(struct inode *inode, struct file *file)
  89 {
  90         if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags))
  91                 return -EBUSY;
  92
  93         clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
  94
  95         ar71xx_wdt_enable();
  96
  97         return nonseekable_open(inode, file);
  98 }
  99
 100 static int ar71xx_wdt_release(struct inode *inode, struct file *file)
 101 {
 102         if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags)) {
 103                 ar71xx_wdt_disable();
 104         } else {
 105                 printk(KERN_CRIT DRV_NAME ": device closed unexpectedly, "
 106                                         "watchdog timer will not stop!\n");
 107         }
 108
 109         clear_bit(WDT_FLAGS_BUSY, &wdt_flags);
 110         clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
 111
 112         return 0;
 113 }
 114
 115 static ssize_t ar71xx_wdt_write(struct file *file, const char *data,
 116                                 size_t len, loff_t *ppos)
 117 {
 118         if (len) {
 119                 if (!nowayout) {
 120                         size_t i;
 121
 122                         clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
 123
 124                         for (i = 0; i != len; i++) {
 125                                 char c;
 126
 127                                 if (get_user(c, data + i))
 128                                         return -EFAULT;
 129
 130                                 if (c == 'V')
 131                                         set_bit(WDT_FLAGS_EXPECT_CLOSE,
 132                                                 &wdt_flags);
 133                         }
 134                 }
 135
 136                 ar71xx_wdt_keepalive();
 137         }
 138
 139         return len;
 140 }
 141
 142 static struct watchdog_info ar71xx_wdt_info = {
 143         .options                = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 144                                   WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
 145         .firmware_version       = 0,
 146         .identity               = "AR71XX watchdog",
 147 };
 148
 149 static int ar71xx_wdt_ioctl(struct inode *inode, struct file *file,
 150                             unsigned int cmd, unsigned long arg)
 151 {
 152         int t;
 153         int ret;
 154
 155         switch (cmd) {
 156         case WDIOC_GETSUPPORT:
 157                 ret = copy_to_user((struct watchdog_info *)arg,
 158                                    &ar71xx_wdt_info,
 159                                    sizeof(&ar71xx_wdt_info)) ? -EFAULT : 0;
 160                 break;
 161
 162         case WDIOC_GETSTATUS:
 163                 ret = put_user(0, (int *)arg) ? -EFAULT : 0;
 164                 break;
 165
 166         case WDIOC_GETBOOTSTATUS:
 167                 ret = put_user(boot_status, (int *)arg) ? -EFAULT : 0;
 168                 break;
 169
 170         case WDIOC_KEEPALIVE:
 171                 ar71xx_wdt_keepalive();
 172                 ret = 0;
 173                 break;
 174
 175         case WDIOC_SETTIMEOUT:
 176                 ret = get_user(t, (int *)arg) ? -EFAULT : 0;
 177                 if (ret)
 178                         break;
 179
 180                 ret = ar71xx_wdt_set_timeout(t);
 181                 if (ret)
 182                         break;
 183
 184                 /* fallthrough */
 185         case WDIOC_GETTIMEOUT:
 186                 ret = put_user(wdt_timeout, (int *)arg) ? -EFAULT : 0;
 187                 break;
 188
 189         default:
 190                 ret = -ENOTTY;
 191                 break;
 192         }
 193
 194         return ret;
 195 }
 196
 197 static const struct file_operations ar71xx_wdt_fops = {
 198         .owner          = THIS_MODULE,
 199         .write          = ar71xx_wdt_write,
 200         .ioctl          = ar71xx_wdt_ioctl,
 201         .open           = ar71xx_wdt_open,
 202         .release        = ar71xx_wdt_release,
 203 };
 204
 205 static struct miscdevice ar71xx_wdt_miscdev = {
 206         .minor = WATCHDOG_MINOR,
 207         .name = "watchdog",
 208         .fops = &ar71xx_wdt_fops,
 209 };
 210
 211 static int __devinit ar71xx_wdt_probe(struct platform_device *pdev)
 212 {
 213         int ret;
 214
 215         max_timeout = (0xfffffffful / ar71xx_ahb_freq);
 216         wdt_timeout = (max_timeout < WDT_TIMEOUT) ? max_timeout : WDT_TIMEOUT;
 217
 218         boot_status =
 219                 (ar71xx_reset_rr(AR71XX_RESET_REG_WDOG_CTRL) & WDOG_CTRL_LAST_RESET) ?
 220                 WDIOF_CARDRESET : 0;
 221
 222         ret = misc_register(&ar71xx_wdt_miscdev);
 223         if (ret)
 224                 goto err_out;
 225
 226         printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
 227
 228         printk(KERN_DEBUG DRV_NAME ": timeout=%d secs (max=%d)\n",
 229                                         wdt_timeout, max_timeout);
 230
 231         return 0;
 232
 233 err_out:
 234         return ret;
 235 }
 236
 237 static int __devexit ar71xx_wdt_remove(struct platform_device *pdev)
 238 {
 239         misc_deregister(&ar71xx_wdt_miscdev);
 240         return 0;
 241 }
 242
 243 static struct platform_driver ar71xx_wdt_driver = {
 244         .probe          = ar71xx_wdt_probe,
 245         .remove         = __devexit_p(ar71xx_wdt_remove),
 246         .driver         = {
 247                 .name   = DRV_NAME,
 248                 .owner  = THIS_MODULE,
 249         },
 250 };
 251
 252 static int __init ar71xx_wdt_init(void)
 253 {
 254         return platform_driver_register(&ar71xx_wdt_driver);
 255 }
 256 module_init(ar71xx_wdt_init);
 257
 258 static void __exit ar71xx_wdt_exit(void)
 259 {
 260         platform_driver_unregister(&ar71xx_wdt_driver);
 261 }
 262 module_exit(ar71xx_wdt_exit);
 263
 264 MODULE_DESCRIPTION(DRV_DESC);
 265 MODULE_VERSION(DRV_VERSION);
 266 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
 267 MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org");
 268 MODULE_LICENSE("GPL v2");
 269 MODULE_ALIAS("platform:" DRV_NAME);
 270 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);