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/kernel.h>
  20#include <linux/miscdevice.h>
  21#include <linux/module.h>
  22#include <linux/moduleparam.h>
  23#include <linux/types.h>
  24#include <linux/uaccess.h>
  25#include <linux/watchdog.h>
  26#include <linux/timer.h>
  27#include <linux/jiffies.h>
  28#include <linux/interrupt.h>
  29#include <linux/ptrace.h>
  30#include <linux/resource.h>
  31#include <linux/platform_device.h>
  32
  33#include <bcm63xx_cpu.h>
  34#include <bcm63xx_io.h>
  35#include <bcm63xx_regs.h>
  36#include <bcm63xx_timer.h>
  37
  38#define PFX KBUILD_MODNAME
  39
  40#define WDT_HZ          50000000 /* Fclk */
  41#define WDT_DEFAULT_TIME        30      /* seconds */
  42#define WDT_MAX_TIME            256     /* seconds */
  43
  44static struct {
  45        void __iomem *regs;
  46        struct timer_list timer;
  47        int default_ticks;
  48        unsigned long inuse;
  49        atomic_t ticks;
  50} bcm63xx_wdt_device;
  51
  52static int expect_close;
  53
  54static int wdt_time = WDT_DEFAULT_TIME;
  55static bool nowayout = WATCHDOG_NOWAYOUT;
  56module_param(nowayout, bool, 0);
  57MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  58        __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  59
  60/* HW functions */
  61static void bcm63xx_wdt_hw_start(void)
  62{
  63        bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
  64        bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  65        bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  66}
  67
  68static void bcm63xx_wdt_hw_stop(void)
  69{
  70        bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  71        bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  72}
  73
  74static void bcm63xx_wdt_isr(void *data)
  75{
  76        struct pt_regs *regs = get_irq_regs();
  77
  78        die(PFX " fire", regs);
  79}
  80
  81static void bcm63xx_timer_tick(unsigned long unused)
  82{
  83        if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
  84                bcm63xx_wdt_hw_start();
  85                mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
  86        } else
  87                pr_crit("watchdog will restart system\n");
  88}
  89
  90static void bcm63xx_wdt_pet(void)
  91{
  92        atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
  93}
  94
  95static void bcm63xx_wdt_start(void)
  96{
  97        bcm63xx_wdt_pet();
  98        bcm63xx_timer_tick(0);
  99}
 100
 101static void bcm63xx_wdt_pause(void)
 102{
 103        del_timer_sync(&bcm63xx_wdt_device.timer);
 104        bcm63xx_wdt_hw_stop();
 105}
 106
 107static int bcm63xx_wdt_settimeout(int new_time)
 108{
 109        if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
 110                return -EINVAL;
 111
 112        wdt_time = new_time;
 113
 114        return 0;
 115}
 116
 117static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
 118{
 119        if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
 120                return -EBUSY;
 121
 122        bcm63xx_wdt_start();
 123        return nonseekable_open(inode, file);
 124}
 125
 126static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
 127{
 128        if (expect_close == 42)
 129                bcm63xx_wdt_pause();
 130        else {
 131                pr_crit("Unexpected close, not stopping watchdog!\n");
 132                bcm63xx_wdt_start();
 133        }
 134        clear_bit(0, &bcm63xx_wdt_device.inuse);
 135        expect_close = 0;
 136        return 0;
 137}
 138
 139static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
 140                                size_t len, loff_t *ppos)
 141{
 142        if (len) {
 143                if (!nowayout) {
 144                        size_t i;
 145
 146                        /* In case it was set long ago */
 147                        expect_close = 0;
 148
 149                        for (i = 0; i != len; i++) {
 150                                char c;
 151                                if (get_user(c, data + i))
 152                                        return -EFAULT;
 153                                if (c == 'V')
 154                                        expect_close = 42;
 155                        }
 156                }
 157                bcm63xx_wdt_pet();
 158        }
 159        return len;
 160}
 161
 162static struct watchdog_info bcm63xx_wdt_info = {
 163        .identity       = PFX,
 164        .options        = WDIOF_SETTIMEOUT |
 165                                WDIOF_KEEPALIVEPING |
 166                                WDIOF_MAGICCLOSE,
 167};
 168
 169
 170static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
 171                                unsigned long arg)
 172{
 173        void __user *argp = (void __user *)arg;
 174        int __user *p = argp;
 175        int new_value, retval = -EINVAL;
 176
 177        switch (cmd) {
 178        case WDIOC_GETSUPPORT:
 179                return copy_to_user(argp, &bcm63xx_wdt_info,
 180                        sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
 181
 182        case WDIOC_GETSTATUS:
 183        case WDIOC_GETBOOTSTATUS:
 184                return put_user(0, p);
 185
 186        case WDIOC_SETOPTIONS:
 187                if (get_user(new_value, p))
 188                        return -EFAULT;
 189
 190                if (new_value & WDIOS_DISABLECARD) {
 191                        bcm63xx_wdt_pause();
 192                        retval = 0;
 193                }
 194                if (new_value & WDIOS_ENABLECARD) {
 195                        bcm63xx_wdt_start();
 196                        retval = 0;
 197                }
 198
 199                return retval;
 200
 201        case WDIOC_KEEPALIVE:
 202                bcm63xx_wdt_pet();
 203                return 0;
 204
 205        case WDIOC_SETTIMEOUT:
 206                if (get_user(new_value, p))
 207                        return -EFAULT;
 208
 209                if (bcm63xx_wdt_settimeout(new_value))
 210                        return -EINVAL;
 211
 212                bcm63xx_wdt_pet();
 213
 214        case WDIOC_GETTIMEOUT:
 215                return put_user(wdt_time, p);
 216
 217        default:
 218                return -ENOTTY;
 219
 220        }
 221}
 222
 223static const struct file_operations bcm63xx_wdt_fops = {
 224        .owner          = THIS_MODULE,
 225        .llseek         = no_llseek,
 226        .write          = bcm63xx_wdt_write,
 227        .unlocked_ioctl = bcm63xx_wdt_ioctl,
 228        .open           = bcm63xx_wdt_open,
 229        .release        = bcm63xx_wdt_release,
 230};
 231
 232static struct miscdevice bcm63xx_wdt_miscdev = {
 233        .minor  = WATCHDOG_MINOR,
 234        .name   = "watchdog",
 235        .fops   = &bcm63xx_wdt_fops,
 236};
 237
 238
 239static int __devinit bcm63xx_wdt_probe(struct platform_device *pdev)
 240{
 241        int ret;
 242        struct resource *r;
 243
 244        setup_timer(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0L);
 245
 246        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 247        if (!r) {
 248                dev_err(&pdev->dev, "failed to get resources\n");
 249                return -ENODEV;
 250        }
 251
 252        bcm63xx_wdt_device.regs = ioremap_nocache(r->start, resource_size(r));
 253        if (!bcm63xx_wdt_device.regs) {
 254                dev_err(&pdev->dev, "failed to remap I/O resources\n");
 255                return -ENXIO;
 256        }
 257
 258        ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL);
 259        if (ret < 0) {
 260                dev_err(&pdev->dev, "failed to register wdt timer isr\n");
 261                goto unmap;
 262        }
 263
 264        if (bcm63xx_wdt_settimeout(wdt_time)) {
 265                bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
 266                dev_info(&pdev->dev,
 267                        ": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
 268                        wdt_time);
 269        }
 270
 271        ret = misc_register(&bcm63xx_wdt_miscdev);
 272        if (ret < 0) {
 273                dev_err(&pdev->dev, "failed to register watchdog device\n");
 274                goto unregister_timer;
 275        }
 276
 277        dev_info(&pdev->dev, " started, timer margin: %d sec\n",
 278                                                WDT_DEFAULT_TIME);
 279
 280        return 0;
 281
 282unregister_timer:
 283        bcm63xx_timer_unregister(TIMER_WDT_ID);
 284unmap:
 285        iounmap(bcm63xx_wdt_device.regs);
 286        return ret;
 287}
 288
 289static int __devexit 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        iounmap(bcm63xx_wdt_device.regs);
 297        return 0;
 298}
 299
 300static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
 301{
 302        bcm63xx_wdt_pause();
 303}
 304
 305static struct platform_driver bcm63xx_wdt_driver = {
 306        .probe  = bcm63xx_wdt_probe,
 307        .remove = __devexit_p(bcm63xx_wdt_remove),
 308        .shutdown = bcm63xx_wdt_shutdown,
 309        .driver = {
 310                .owner = THIS_MODULE,
 311                .name = "bcm63xx-wdt",
 312        }
 313};
 314
 315module_platform_driver(bcm63xx_wdt_driver);
 316
 317MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
 318MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 319MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
 320MODULE_LICENSE("GPL");
 321MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 322MODULE_ALIAS("platform:bcm63xx-wdt");
 323
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