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) 2010-2011 Jaiganesh Narayanan <jnarayanan@atheros.com>
   5  * Copyright (C) 2008 Gabor Juhos <juhosg@openwrt.org>
   6  * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
   7  *
   8  * Parts of this file are based on Atheros 2.6.31 BSP
   9  *
  10  * This driver was based on: drivers/watchdog/ixp4xx_wdt.c
  11  *      Author: Deepak Saxena <dsaxena@plexity.net>
  12  *      Copyright 2004 (c) MontaVista, Software, Inc.
  13  *
  14  * which again was based on sa1100 driver,
  15  *      Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
  16  *
  17  * This program is free software; you can redistribute it and/or modify it
  18  * under the terms of the GNU General Public License version 2 as published
  19  * by the Free Software Foundation.
  20  *
  21  */
  22
  23 #include <linux/bitops.h>
  24 #include <linux/errno.h>
  25 #include <linux/fs.h>
  26 #include <linux/init.h>
  27 #include <linux/kernel.h>
  28 #include <linux/miscdevice.h>
  29 #include <linux/module.h>
  30 #include <linux/moduleparam.h>
  31 #include <linux/platform_device.h>
  32 #include <linux/types.h>
  33 #include <linux/watchdog.h>
  34 #include <linux/delay.h>
  35
  36 #include <asm/mach-ar71xx/ar71xx.h>
  37
  38 #define DRV_NAME        "ar71xx-wdt"
  39 #define DRV_DESC        "Atheros AR71xx hardware watchdog driver"
  40 #define DRV_VERSION     "0.1.0"
  41
  42 #define WDT_TIMEOUT     15      /* seconds */
  43
  44 static int nowayout = WATCHDOG_NOWAYOUT;
  45
  46 #ifdef CONFIG_WATCHDOG_NOWAYOUT
  47 module_param(nowayout, int, 0);
  48 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
  49                            "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  50 #endif
  51
  52 static unsigned long wdt_flags;
  53
  54 #define WDT_FLAGS_BUSY          0
  55 #define WDT_FLAGS_EXPECT_CLOSE  1
  56
  57 static int wdt_timeout = WDT_TIMEOUT;
  58 static int boot_status;
  59 static int max_timeout;
  60 static u32 wdt_clk_freq;
  61
  62 static inline void ar71xx_wdt_keepalive(void)
  63 {
  64         ar71xx_reset_wr(AR71XX_RESET_REG_WDOG, wdt_clk_freq * wdt_timeout);
  65 }
  66
  67 static inline void ar71xx_wdt_enable(void)
  68 {
  69         printk(KERN_DEBUG DRV_NAME ": enabling watchdog timer\n");
  70         ar71xx_wdt_keepalive();
  71         udelay(2);
  72         ar71xx_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_FCR);
  73 }
  74
  75 static inline void ar71xx_wdt_disable(void)
  76 {
  77         printk(KERN_DEBUG DRV_NAME ": disabling watchdog timer\n");
  78         ar71xx_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_NONE);
  79 }
  80
  81 static int ar71xx_wdt_set_timeout(int val)
  82 {
  83         if (val < 1 || val > max_timeout)
  84                 return -EINVAL;
  85
  86         wdt_timeout = val;
  87         ar71xx_wdt_keepalive();
  88
  89         printk(KERN_DEBUG DRV_NAME ": timeout=%d secs\n", wdt_timeout);
  90
  91         return 0;
  92 }
  93
  94 static int ar71xx_wdt_open(struct inode *inode, struct file *file)
  95 {
  96         if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags))
  97                 return -EBUSY;
  98
  99         clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
 100
 101         ar71xx_wdt_enable();
 102
 103         return nonseekable_open(inode, file);
 104 }
 105
 106 static int ar71xx_wdt_release(struct inode *inode, struct file *file)
 107 {
 108         if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags)) {
 109                 ar71xx_wdt_disable();
 110         } else {
 111                 printk(KERN_CRIT DRV_NAME ": device closed unexpectedly, "
 112                                         "watchdog timer will not stop!\n");
 113         }
 114
 115         clear_bit(WDT_FLAGS_BUSY, &wdt_flags);
 116         clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
 117
 118         return 0;
 119 }
 120
 121 static ssize_t ar71xx_wdt_write(struct file *file, const char *data,
 122                                 size_t len, loff_t *ppos)
 123 {
 124         if (len) {
 125                 if (!nowayout) {
 126                         size_t i;
 127
 128                         clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
 129
 130                         for (i = 0; i != len; i++) {
 131                                 char c;
 132
 133                                 if (get_user(c, data + i))
 134                                         return -EFAULT;
 135
 136                                 if (c == 'V')
 137                                         set_bit(WDT_FLAGS_EXPECT_CLOSE,
 138                                                 &wdt_flags);
 139                         }
 140                 }
 141
 142                 ar71xx_wdt_keepalive();
 143         }
 144
 145         return len;
 146 }
 147
 148 static struct watchdog_info ar71xx_wdt_info = {
 149         .options                = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 150                                   WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
 151         .firmware_version       = 0,
 152         .identity               = "AR71XX watchdog",
 153 };
 154
 155 static long ar71xx_wdt_ioctl(struct file *file,
 156                             unsigned int cmd, unsigned long arg)
 157 {
 158         int t;
 159         int ret;
 160
 161         switch (cmd) {
 162         case WDIOC_GETSUPPORT:
 163                 ret = copy_to_user((struct watchdog_info *)arg,
 164                                    &ar71xx_wdt_info,
 165                                    sizeof(ar71xx_wdt_info)) ? -EFAULT : 0;
 166                 break;
 167
 168         case WDIOC_GETSTATUS:
 169                 ret = put_user(0, (int *)arg) ? -EFAULT : 0;
 170                 break;
 171
 172         case WDIOC_GETBOOTSTATUS:
 173                 ret = put_user(boot_status, (int *)arg) ? -EFAULT : 0;
 174                 break;
 175
 176         case WDIOC_KEEPALIVE:
 177                 ar71xx_wdt_keepalive();
 178                 ret = 0;
 179                 break;
 180
 181         case WDIOC_SETTIMEOUT:
 182                 ret = get_user(t, (int *)arg) ? -EFAULT : 0;
 183                 if (ret)
 184                         break;
 185
 186                 ret = ar71xx_wdt_set_timeout(t);
 187                 if (ret)
 188                         break;
 189
 190                 /* fallthrough */
 191         case WDIOC_GETTIMEOUT:
 192                 ret = put_user(wdt_timeout, (int *)arg) ? -EFAULT : 0;
 193                 break;
 194
 195         default:
 196                 ret = -ENOTTY;
 197                 break;
 198         }
 199
 200         return ret;
 201 }
 202
 203 static const struct file_operations ar71xx_wdt_fops = {
 204         .owner          = THIS_MODULE,
 205         .write          = ar71xx_wdt_write,
 206         .unlocked_ioctl = ar71xx_wdt_ioctl,
 207         .open           = ar71xx_wdt_open,
 208         .release        = ar71xx_wdt_release,
 209 };
 210
 211 static struct miscdevice ar71xx_wdt_miscdev = {
 212         .minor = WATCHDOG_MINOR,
 213         .name = "watchdog",
 214         .fops = &ar71xx_wdt_fops,
 215 };
 216
 217 static int __devinit ar71xx_wdt_probe(struct platform_device *pdev)
 218 {
 219         int ret;
 220
 221         switch (ar71xx_soc) {
 222         case AR71XX_SOC_AR9341:
 223         case AR71XX_SOC_AR9342:
 224         case AR71XX_SOC_AR9344:
 225                 wdt_clk_freq = ar71xx_ref_freq;
 226                 break;
 227
 228         default:
 229                 wdt_clk_freq = ar71xx_ahb_freq;
 230                 break;
 231         }
 232
 233         max_timeout = (0xfffffffful / wdt_clk_freq);
 234         wdt_timeout = (max_timeout < WDT_TIMEOUT) ? max_timeout : WDT_TIMEOUT;
 235
 236         if (ar71xx_reset_rr(AR71XX_RESET_REG_WDOG_CTRL) & WDOG_CTRL_LAST_RESET)
 237                 boot_status = WDIOF_CARDRESET;
 238
 239         ret = misc_register(&ar71xx_wdt_miscdev);
 240         if (ret)
 241                 goto err_out;
 242
 243         printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
 244
 245         printk(KERN_DEBUG DRV_NAME ": timeout=%d secs (max=%d)\n",
 246                                         wdt_timeout, max_timeout);
 247
 248         return 0;
 249
 250 err_out:
 251         return ret;
 252 }
 253
 254 static int __devexit ar71xx_wdt_remove(struct platform_device *pdev)
 255 {
 256         misc_deregister(&ar71xx_wdt_miscdev);
 257         return 0;
 258 }
 259
 260 static struct platform_driver ar71xx_wdt_driver = {
 261         .probe          = ar71xx_wdt_probe,
 262         .remove         = __devexit_p(ar71xx_wdt_remove),
 263         .driver         = {
 264                 .name   = DRV_NAME,
 265                 .owner  = THIS_MODULE,
 266         },
 267 };
 268
 269 static int __init ar71xx_wdt_init(void)
 270 {
 271         return platform_driver_register(&ar71xx_wdt_driver);
 272 }
 273 module_init(ar71xx_wdt_init);
 274
 275 static void __exit ar71xx_wdt_exit(void)
 276 {
 277         platform_driver_unregister(&ar71xx_wdt_driver);
 278 }
 279 module_exit(ar71xx_wdt_exit);
 280
 281 MODULE_DESCRIPTION(DRV_DESC);
 282 MODULE_VERSION(DRV_VERSION);
 283 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
 284 MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org");
 285 MODULE_LICENSE("GPL v2");
 286 MODULE_ALIAS("platform:" DRV_NAME);
 287 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);