linux/drivers/watchdog/bcm63xx_wdt.c
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   1/*
   2 *  Broadcom BCM63xx SoC watchdog driver
   3 *
   4 *  Copyright (C) 2007, Miguel Gaio <miguel.gaio@efixo.com>
   5 *  Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
   6 *
   7 *  This program is free software; you can redistribute it and/or
   8 *  modify it under the terms of the GNU General Public License
   9 *  as published by the Free Software Foundation; either version
  10 *  2 of the License, or (at your option) any later version.
  11 */
  12
  13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15#include <linux/bitops.h>
  16#include <linux/errno.h>
  17#include <linux/fs.h>
  18#include <linux/init.h>
  19#include <linux/io.h>
  20#include <linux/kernel.h>
  21#include <linux/miscdevice.h>
  22#include <linux/module.h>
  23#include <linux/moduleparam.h>
  24#include <linux/types.h>
  25#include <linux/uaccess.h>
  26#include <linux/watchdog.h>
  27#include <linux/timer.h>
  28#include <linux/jiffies.h>
  29#include <linux/interrupt.h>
  30#include <linux/ptrace.h>
  31#include <linux/resource.h>
  32#include <linux/platform_device.h>
  33
  34#include <bcm63xx_cpu.h>
  35#include <bcm63xx_io.h>
  36#include <bcm63xx_regs.h>
  37#include <bcm63xx_timer.h>
  38
  39#define PFX KBUILD_MODNAME
  40
  41#define WDT_HZ          50000000 /* Fclk */
  42#define WDT_DEFAULT_TIME        30      /* seconds */
  43#define WDT_MAX_TIME            256     /* seconds */
  44
  45static struct {
  46        void __iomem *regs;
  47        struct timer_list timer;
  48        int default_ticks;
  49        unsigned long inuse;
  50        atomic_t ticks;
  51} bcm63xx_wdt_device;
  52
  53static int expect_close;
  54
  55static int wdt_time = WDT_DEFAULT_TIME;
  56static bool nowayout = WATCHDOG_NOWAYOUT;
  57module_param(nowayout, bool, 0);
  58MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  59        __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  60
  61/* HW functions */
  62static void bcm63xx_wdt_hw_start(void)
  63{
  64        bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
  65        bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  66        bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  67}
  68
  69static void bcm63xx_wdt_hw_stop(void)
  70{
  71        bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  72        bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  73}
  74
  75static void bcm63xx_wdt_isr(void *data)
  76{
  77        struct pt_regs *regs = get_irq_regs();
  78
  79        die(PFX " fire", regs);
  80}
  81
  82static void bcm63xx_timer_tick(unsigned long unused)
  83{
  84        if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
  85                bcm63xx_wdt_hw_start();
  86                mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
  87        } else
  88                pr_crit("watchdog will restart system\n");
  89}
  90
  91static void bcm63xx_wdt_pet(void)
  92{
  93        atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
  94}
  95
  96static void bcm63xx_wdt_start(void)
  97{
  98        bcm63xx_wdt_pet();
  99        bcm63xx_timer_tick(0);
 100}
 101
 102static void bcm63xx_wdt_pause(void)
 103{
 104        del_timer_sync(&bcm63xx_wdt_device.timer);
 105        bcm63xx_wdt_hw_stop();
 106}
 107
 108static int bcm63xx_wdt_settimeout(int new_time)
 109{
 110        if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
 111                return -EINVAL;
 112
 113        wdt_time = new_time;
 114
 115        return 0;
 116}
 117
 118static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
 119{
 120        if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
 121                return -EBUSY;
 122
 123        bcm63xx_wdt_start();
 124        return nonseekable_open(inode, file);
 125}
 126
 127static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
 128{
 129        if (expect_close == 42)
 130                bcm63xx_wdt_pause();
 131        else {
 132                pr_crit("Unexpected close, not stopping watchdog!\n");
 133                bcm63xx_wdt_start();
 134        }
 135        clear_bit(0, &bcm63xx_wdt_device.inuse);
 136        expect_close = 0;
 137        return 0;
 138}
 139
 140static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
 141                                size_t len, loff_t *ppos)
 142{
 143        if (len) {
 144                if (!nowayout) {
 145                        size_t i;
 146
 147                        /* In case it was set long ago */
 148                        expect_close = 0;
 149
 150                        for (i = 0; i != len; i++) {
 151                                char c;
 152                                if (get_user(c, data + i))
 153                                        return -EFAULT;
 154                                if (c == 'V')
 155                                        expect_close = 42;
 156                        }
 157                }
 158                bcm63xx_wdt_pet();
 159        }
 160        return len;
 161}
 162
 163static struct watchdog_info bcm63xx_wdt_info = {
 164        .identity       = PFX,
 165        .options        = WDIOF_SETTIMEOUT |
 166                                WDIOF_KEEPALIVEPING |
 167                                WDIOF_MAGICCLOSE,
 168};
 169
 170
 171static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
 172                                unsigned long arg)
 173{
 174        void __user *argp = (void __user *)arg;
 175        int __user *p = argp;
 176        int new_value, retval = -EINVAL;
 177
 178        switch (cmd) {
 179        case WDIOC_GETSUPPORT:
 180                return copy_to_user(argp, &bcm63xx_wdt_info,
 181                        sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
 182
 183        case WDIOC_GETSTATUS:
 184        case WDIOC_GETBOOTSTATUS:
 185                return put_user(0, p);
 186
 187        case WDIOC_SETOPTIONS:
 188                if (get_user(new_value, p))
 189                        return -EFAULT;
 190
 191                if (new_value & WDIOS_DISABLECARD) {
 192                        bcm63xx_wdt_pause();
 193                        retval = 0;
 194                }
 195                if (new_value & WDIOS_ENABLECARD) {
 196                        bcm63xx_wdt_start();
 197                        retval = 0;
 198                }
 199
 200                return retval;
 201
 202        case WDIOC_KEEPALIVE:
 203                bcm63xx_wdt_pet();
 204                return 0;
 205
 206        case WDIOC_SETTIMEOUT:
 207                if (get_user(new_value, p))
 208                        return -EFAULT;
 209
 210                if (bcm63xx_wdt_settimeout(new_value))
 211                        return -EINVAL;
 212
 213                bcm63xx_wdt_pet();
 214
 215        case WDIOC_GETTIMEOUT:
 216                return put_user(wdt_time, p);
 217
 218        default:
 219                return -ENOTTY;
 220
 221        }
 222}
 223
 224static const struct file_operations bcm63xx_wdt_fops = {
 225        .owner          = THIS_MODULE,
 226        .llseek         = no_llseek,
 227        .write          = bcm63xx_wdt_write,
 228        .unlocked_ioctl = bcm63xx_wdt_ioctl,
 229        .open           = bcm63xx_wdt_open,
 230        .release        = bcm63xx_wdt_release,
 231};
 232
 233static struct miscdevice bcm63xx_wdt_miscdev = {
 234        .minor  = WATCHDOG_MINOR,
 235        .name   = "watchdog",
 236        .fops   = &bcm63xx_wdt_fops,
 237};
 238
 239
 240static int bcm63xx_wdt_probe(struct platform_device *pdev)
 241{
 242        int ret;
 243        struct resource *r;
 244
 245        setup_timer(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0L);
 246
 247        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 248        if (!r) {
 249                dev_err(&pdev->dev, "failed to get resources\n");
 250                return -ENODEV;
 251        }
 252
 253        bcm63xx_wdt_device.regs = devm_ioremap_nocache(&pdev->dev, r->start,
 254                                                        resource_size(r));
 255        if (!bcm63xx_wdt_device.regs) {
 256                dev_err(&pdev->dev, "failed to remap I/O resources\n");
 257                return -ENXIO;
 258        }
 259
 260        ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL);
 261        if (ret < 0) {
 262                dev_err(&pdev->dev, "failed to register wdt timer isr\n");
 263                return ret;
 264        }
 265
 266        if (bcm63xx_wdt_settimeout(wdt_time)) {
 267                bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
 268                dev_info(&pdev->dev,
 269                        ": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
 270                        wdt_time);
 271        }
 272
 273        ret = misc_register(&bcm63xx_wdt_miscdev);
 274        if (ret < 0) {
 275                dev_err(&pdev->dev, "failed to register watchdog device\n");
 276                goto unregister_timer;
 277        }
 278
 279        dev_info(&pdev->dev, " started, timer margin: %d sec\n",
 280                                                WDT_DEFAULT_TIME);
 281
 282        return 0;
 283
 284unregister_timer:
 285        bcm63xx_timer_unregister(TIMER_WDT_ID);
 286        return ret;
 287}
 288
 289static int bcm63xx_wdt_remove(struct platform_device *pdev)
 290{
 291        if (!nowayout)
 292                bcm63xx_wdt_pause();
 293
 294        misc_deregister(&bcm63xx_wdt_miscdev);
 295        bcm63xx_timer_unregister(TIMER_WDT_ID);
 296        return 0;
 297}
 298
 299static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
 300{
 301        bcm63xx_wdt_pause();
 302}
 303
 304static struct platform_driver bcm63xx_wdt_driver = {
 305        .probe  = bcm63xx_wdt_probe,
 306        .remove = bcm63xx_wdt_remove,
 307        .shutdown = bcm63xx_wdt_shutdown,
 308        .driver = {
 309                .owner = THIS_MODULE,
 310                .name = "bcm63xx-wdt",
 311        }
 312};
 313
 314module_platform_driver(bcm63xx_wdt_driver);
 315
 316MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
 317MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 318MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
 319MODULE_LICENSE("GPL");
 320MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 321MODULE_ALIAS("platform:bcm63xx-wdt");
 322
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