LXR linux/drivers/watchdog/pnx833x

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *  PNX833x Hardware Watchdog Driver
   4 *  Copyright 2008 NXP Semiconductors
   5 *  Daniel Laird <daniel.j.laird@nxp.com>
   6 *  Andre McCurdy <andre.mccurdy@nxp.com>
   7 *
   8 *  Heavily based upon - IndyDog        0.3
   9 *  A Hardware Watchdog Device for SGI IP22
  10 *
  11 * (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>, All Rights Reserved.
  12 *
  13 * based on softdog.c by Alan Cox <alan@redhat.com>
  14 */
  15
  16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  17
  18#include <linux/module.h>
  19#include <linux/moduleparam.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/notifier.h>
  27#include <linux/reboot.h>
  28#include <linux/init.h>
  29#include <asm/mach-pnx833x/pnx833x.h>
  30
  31#define WATCHDOG_TIMEOUT 30             /* 30 sec Maximum timeout */
  32#define WATCHDOG_COUNT_FREQUENCY 68000000U /* Watchdog counts at 68MHZ. */
  33#define PNX_WATCHDOG_TIMEOUT    (WATCHDOG_TIMEOUT * WATCHDOG_COUNT_FREQUENCY)
  34#define PNX_TIMEOUT_VALUE       2040000000U
  35
  36/** CONFIG block */
  37#define PNX833X_CONFIG                      (0x07000U)
  38#define PNX833X_CONFIG_CPU_WATCHDOG         (0x54)
  39#define PNX833X_CONFIG_CPU_WATCHDOG_COMPARE (0x58)
  40#define PNX833X_CONFIG_CPU_COUNTERS_CONTROL (0x1c)
  41
  42/** RESET block */
  43#define PNX833X_RESET                       (0x08000U)
  44#define PNX833X_RESET_CONFIG                (0x08)
  45
  46static int pnx833x_wdt_alive;
  47
  48/* Set default timeout in MHZ.*/
  49static int pnx833x_wdt_timeout = PNX_WATCHDOG_TIMEOUT;
  50module_param(pnx833x_wdt_timeout, int, 0);
  51MODULE_PARM_DESC(timeout, "Watchdog timeout in Mhz. (68Mhz clock), default="
  52                        __MODULE_STRING(PNX_TIMEOUT_VALUE) "(30 seconds).");
  53
  54static bool nowayout = WATCHDOG_NOWAYOUT;
  55module_param(nowayout, bool, 0);
  56MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  57                                        __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  58
  59#define START_DEFAULT   1
  60static int start_enabled = START_DEFAULT;
  61module_param(start_enabled, int, 0);
  62MODULE_PARM_DESC(start_enabled, "Watchdog is started on module insertion "
  63                                "(default=" __MODULE_STRING(START_DEFAULT) ")");
  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        pr_info("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        pr_info("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        pr_info("Started watchdog timer\n");
 114
 115        return stream_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 const 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 int __init watchdog_init(void)
 233{
 234        int ret, cause;
 235
 236        /* Lets check the reason for the reset.*/
 237        cause = PNX833X_REG(PNX833X_RESET);
 238        /*If bit 31 is set then watchdog was cause of reset.*/
 239        if (cause & 0x80000000) {
 240                pr_info("The system was previously reset due to the watchdog firing - please investigate...\n");
 241        }
 242
 243        ret = register_reboot_notifier(&pnx833x_wdt_notifier);
 244        if (ret) {
 245                pr_err("cannot register reboot notifier (err=%d)\n", ret);
 246                return ret;
 247        }
 248
 249        ret = misc_register(&pnx833x_wdt_miscdev);
 250        if (ret) {
 251                pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 252                       WATCHDOG_MINOR, ret);
 253                unregister_reboot_notifier(&pnx833x_wdt_notifier);
 254                return ret;
 255        }
 256
 257        pr_info("Hardware Watchdog Timer for PNX833x: Version 0.1\n");
 258
 259        if (start_enabled)
 260                pnx833x_wdt_start();
 261
 262        return 0;
 263}
 264
 265static void __exit watchdog_exit(void)
 266{
 267        misc_deregister(&pnx833x_wdt_miscdev);
 268        unregister_reboot_notifier(&pnx833x_wdt_notifier);
 269}
 270
 271module_init(watchdog_init);
 272module_exit(watchdog_exit);
 273
 274MODULE_AUTHOR("Daniel Laird/Andre McCurdy");
 275MODULE_DESCRIPTION("Hardware Watchdog Device for PNX833x");
 276MODULE_LICENSE("GPL");
 277