LXR linux/drivers/watchdog/pnx833x

   1/*
   2 *  PNX833x Hardware Watchdog Driver
   3 *  Copyright 2008 NXP Semiconductors
   4 *  Daniel Laird <daniel.j.laird@nxp.com>
   5 *  Andre McCurdy <andre.mccurdy@nxp.com>
   6 *
   7 *  Heavily based upon - IndyDog        0.3
   8 *  A Hardware Watchdog Device for SGI IP22
   9 *
  10 * (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>, 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 * based on softdog.c by Alan Cox <alan@redhat.com>
  18 */
  19
  20#include <linux/module.h>
  21#include <linux/moduleparam.h>
  22#include <linux/types.h>
  23#include <linux/kernel.h>
  24#include <linux/fs.h>
  25#include <linux/mm.h>
  26#include <linux/miscdevice.h>
  27#include <linux/watchdog.h>
  28#include <linux/notifier.h>
  29#include <linux/reboot.h>
  30#include <linux/init.h>
  31#include <asm/mach-pnx833x/pnx833x.h>
  32
  33#define PFX "pnx833x: "
  34#define WATCHDOG_TIMEOUT 30             /* 30 sec Maximum timeout */
  35#define WATCHDOG_COUNT_FREQUENCY 68000000U /* Watchdog counts at 68MHZ. */
  36
  37/** CONFIG block */
  38#define PNX833X_CONFIG                      (0x07000U)
  39#define PNX833X_CONFIG_CPU_WATCHDOG         (0x54)
  40#define PNX833X_CONFIG_CPU_WATCHDOG_COMPARE (0x58)
  41#define PNX833X_CONFIG_CPU_COUNTERS_CONTROL (0x1c)
  42
  43/** RESET block */
  44#define PNX833X_RESET                       (0x08000U)
  45#define PNX833X_RESET_CONFIG                (0x08)
  46
  47static int pnx833x_wdt_alive;
  48
  49/* Set default timeout in MHZ.*/
  50static int pnx833x_wdt_timeout = (WATCHDOG_TIMEOUT * WATCHDOG_COUNT_FREQUENCY);
  51module_param(pnx833x_wdt_timeout, int, 0);
  52MODULE_PARM_DESC(timeout, "Watchdog timeout in Mhz. (68Mhz clock), default="
  53                        __MODULE_STRING(pnx833x_wdt_timeout) "(30 seconds).");
  54
  55static int nowayout = WATCHDOG_NOWAYOUT;
  56module_param(nowayout, int, 0);
  57MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  58                                        __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  59
  60static int start_enabled = 1;
  61module_param(start_enabled, int, 0);
  62MODULE_PARM_DESC(start_enabled, "Watchdog is started on module insertion "
  63                                "(default=" __MODULE_STRING(start_enabled) ")");
  64
  65static void pnx833x_wdt_start(void)
  66{
  67        /* Enable watchdog causing reset. */
  68        PNX833X_REG(PNX833X_RESET + PNX833X_RESET_CONFIG) |= 0x1;
  69        /* Set timeout.*/
  70        PNX833X_REG(PNX833X_CONFIG +
  71                PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = pnx833x_wdt_timeout;
  72        /* Enable watchdog. */
  73        PNX833X_REG(PNX833X_CONFIG +
  74                                PNX833X_CONFIG_CPU_COUNTERS_CONTROL) |= 0x1;
  75
  76        printk(KERN_INFO PFX "Started watchdog timer.\n");
  77}
  78
  79static void pnx833x_wdt_stop(void)
  80{
  81        /* Disable watchdog causing reset. */
  82        PNX833X_REG(PNX833X_RESET + PNX833X_CONFIG) &= 0xFFFFFFFE;
  83        /* Disable watchdog.*/
  84        PNX833X_REG(PNX833X_CONFIG +
  85                        PNX833X_CONFIG_CPU_COUNTERS_CONTROL) &= 0xFFFFFFFE;
  86
  87        printk(KERN_INFO PFX "Stopped watchdog timer.\n");
  88}
  89
  90static void pnx833x_wdt_ping(void)
  91{
  92        PNX833X_REG(PNX833X_CONFIG +
  93                PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = pnx833x_wdt_timeout;
  94}
  95
  96/*
  97 *      Allow only one person to hold it open
  98 */
  99static int pnx833x_wdt_open(struct inode *inode, struct file *file)
 100{
 101        if (test_and_set_bit(0, &pnx833x_wdt_alive))
 102                return -EBUSY;
 103
 104        if (nowayout)
 105                __module_get(THIS_MODULE);
 106
 107        /* Activate timer */
 108        if (!start_enabled)
 109                pnx833x_wdt_start();
 110
 111        pnx833x_wdt_ping();
 112
 113        printk(KERN_INFO "Started watchdog timer.\n");
 114
 115        return nonseekable_open(inode, file);
 116}
 117
 118static int pnx833x_wdt_release(struct inode *inode, struct file *file)
 119{
 120        /* Shut off the timer.
 121         * Lock it in if it's a module and we defined ...NOWAYOUT */
 122        if (!nowayout)
 123                pnx833x_wdt_stop(); /* Turn the WDT off */
 124
 125        clear_bit(0, &pnx833x_wdt_alive);
 126        return 0;
 127}
 128
 129static ssize_t pnx833x_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
 130{
 131        /* Refresh the timer. */
 132        if (len)
 133                pnx833x_wdt_ping();
 134
 135        return len;
 136}
 137
 138static long pnx833x_wdt_ioctl(struct file *file, unsigned int cmd,
 139                                                        unsigned long arg)
 140{
 141        int options, new_timeout = 0;
 142        uint32_t timeout, timeout_left = 0;
 143
 144        static struct watchdog_info ident = {
 145                .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
 146                .firmware_version = 0,
 147                .identity = "Hardware Watchdog for PNX833x",
 148        };
 149
 150        switch (cmd) {
 151        default:
 152                return -ENOTTY;
 153
 154        case WDIOC_GETSUPPORT:
 155                if (copy_to_user((struct watchdog_info *)arg,
 156                                 &ident, sizeof(ident)))
 157                        return -EFAULT;
 158                return 0;
 159
 160        case WDIOC_GETSTATUS:
 161        case WDIOC_GETBOOTSTATUS:
 162                return put_user(0, (int *)arg);
 163
 164        case WDIOC_SETOPTIONS:
 165                if (get_user(options, (int *)arg))
 166                        return -EFAULT;
 167
 168                if (options & WDIOS_DISABLECARD)
 169                        pnx833x_wdt_stop();
 170
 171                if (options & WDIOS_ENABLECARD)
 172                        pnx833x_wdt_start();
 173
 174                return 0;
 175
 176        case WDIOC_KEEPALIVE:
 177                pnx833x_wdt_ping();
 178                return 0;
 179
 180        case WDIOC_SETTIMEOUT:
 181        {
 182                if (get_user(new_timeout, (int *)arg))
 183                        return -EFAULT;
 184
 185                pnx833x_wdt_timeout = new_timeout;
 186                PNX833X_REG(PNX833X_CONFIG +
 187                        PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = new_timeout;
 188                return put_user(new_timeout, (int *)arg);
 189        }
 190
 191        case WDIOC_GETTIMEOUT:
 192                timeout = PNX833X_REG(PNX833X_CONFIG +
 193                                        PNX833X_CONFIG_CPU_WATCHDOG_COMPARE);
 194                return put_user(timeout, (int *)arg);
 195
 196        case WDIOC_GETTIMELEFT:
 197                timeout_left = PNX833X_REG(PNX833X_CONFIG +
 198                                                PNX833X_CONFIG_CPU_WATCHDOG);
 199                return put_user(timeout_left, (int *)arg);
 200
 201        }
 202}
 203
 204static int pnx833x_wdt_notify_sys(struct notifier_block *this,
 205                                        unsigned long code, void *unused)
 206{
 207        if (code == SYS_DOWN || code == SYS_HALT)
 208                pnx833x_wdt_stop(); /* Turn the WDT off */
 209
 210        return NOTIFY_DONE;
 211}
 212
 213static const struct file_operations pnx833x_wdt_fops = {
 214        .owner          = THIS_MODULE,
 215        .llseek         = no_llseek,
 216        .write          = pnx833x_wdt_write,
 217        .unlocked_ioctl = pnx833x_wdt_ioctl,
 218        .open           = pnx833x_wdt_open,
 219        .release        = pnx833x_wdt_release,
 220};
 221
 222static struct miscdevice pnx833x_wdt_miscdev = {
 223        .minor          = WATCHDOG_MINOR,
 224        .name           = "watchdog",
 225        .fops           = &pnx833x_wdt_fops,
 226};
 227
 228static struct notifier_block pnx833x_wdt_notifier = {
 229        .notifier_call = pnx833x_wdt_notify_sys,
 230};
 231
 232static char banner[] __initdata =
 233        KERN_INFO PFX "Hardware Watchdog Timer for PNX833x: Version 0.1\n";
 234
 235static int __init watchdog_init(void)
 236{
 237        int ret, cause;
 238
 239        /* Lets check the reason for the reset.*/
 240        cause = PNX833X_REG(PNX833X_RESET);
 241        /*If bit 31 is set then watchdog was cause of reset.*/
 242        if (cause & 0x80000000) {
 243                printk(KERN_INFO PFX "The system was previously reset due to "
 244                        "the watchdog firing - please investigate...\n");
 245        }
 246
 247        ret = register_reboot_notifier(&pnx833x_wdt_notifier);
 248        if (ret) {
 249                printk(KERN_ERR PFX
 250                        "cannot register reboot notifier (err=%d)\n", ret);
 251                return ret;
 252        }
 253
 254        ret = misc_register(&pnx833x_wdt_miscdev);
 255        if (ret) {
 256                printk(KERN_ERR PFX
 257                        "cannot register miscdev on minor=%d (err=%d)\n",
 258                        WATCHDOG_MINOR, ret);
 259                unregister_reboot_notifier(&pnx833x_wdt_notifier);
 260                return ret;
 261        }
 262
 263        printk(banner);
 264        if (start_enabled)
 265                pnx833x_wdt_start();
 266
 267        return 0;
 268}
 269
 270static void __exit watchdog_exit(void)
 271{
 272        misc_deregister(&pnx833x_wdt_miscdev);
 273        unregister_reboot_notifier(&pnx833x_wdt_notifier);
 274}
 275
 276module_init(watchdog_init);
 277module_exit(watchdog_exit);
 278
 279MODULE_AUTHOR("Daniel Laird/Andre McCurdy");
 280MODULE_DESCRIPTION("Hardware Watchdog Device for PNX833x");
 281MODULE_LICENSE("GPL");
 282MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 283