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#include <linux/bitops.h>
  14#include <linux/errno.h>
  15#include <linux/fs.h>
  16#include <linux/init.h>
  17#include <linux/kernel.h>
  18#include <linux/miscdevice.h>
  19#include <linux/module.h>
  20#include <linux/moduleparam.h>
  21#include <linux/types.h>
  22#include <linux/uaccess.h>
  23#include <linux/watchdog.h>
  24#include <linux/timer.h>
  25#include <linux/jiffies.h>
  26#include <linux/interrupt.h>
  27#include <linux/ptrace.h>
  28#include <linux/resource.h>
  29#include <linux/platform_device.h>
  30
  31#include <bcm63xx_cpu.h>
  32#include <bcm63xx_io.h>
  33#include <bcm63xx_regs.h>
  34#include <bcm63xx_timer.h>
  35
  36#define PFX KBUILD_MODNAME
  37
  38#define WDT_HZ          50000000 /* Fclk */
  39#define WDT_DEFAULT_TIME        30      /* seconds */
  40#define WDT_MAX_TIME            256     /* seconds */
  41
  42static struct {
  43        void __iomem *regs;
  44        struct timer_list timer;
  45        int default_ticks;
  46        unsigned long inuse;
  47        atomic_t ticks;
  48} bcm63xx_wdt_device;
  49
  50static int expect_close;
  51
  52static int wdt_time = WDT_DEFAULT_TIME;
  53static int nowayout = WATCHDOG_NOWAYOUT;
  54module_param(nowayout, int, 0);
  55MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  56        __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  57
  58/* HW functions */
  59static void bcm63xx_wdt_hw_start(void)
  60{
  61        bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
  62        bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  63        bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  64}
  65
  66static void bcm63xx_wdt_hw_stop(void)
  67{
  68        bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  69        bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
  70}
  71
  72static void bcm63xx_wdt_isr(void *data)
  73{
  74        struct pt_regs *regs = get_irq_regs();
  75
  76        die(PFX " fire", regs);
  77}
  78
  79static void bcm63xx_timer_tick(unsigned long unused)
  80{
  81        if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
  82                bcm63xx_wdt_hw_start();
  83                mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
  84        } else
  85                printk(KERN_CRIT PFX ": watchdog will restart system\n");
  86}
  87
  88static void bcm63xx_wdt_pet(void)
  89{
  90        atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
  91}
  92
  93static void bcm63xx_wdt_start(void)
  94{
  95        bcm63xx_wdt_pet();
  96        bcm63xx_timer_tick(0);
  97}
  98
  99static void bcm63xx_wdt_pause(void)
 100{
 101        del_timer_sync(&bcm63xx_wdt_device.timer);
 102        bcm63xx_wdt_hw_stop();
 103}
 104
 105static int bcm63xx_wdt_settimeout(int new_time)
 106{
 107        if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
 108                return -EINVAL;
 109
 110        wdt_time = new_time;
 111
 112        return 0;
 113}
 114
 115static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
 116{
 117        if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
 118                return -EBUSY;
 119
 120        bcm63xx_wdt_start();
 121        return nonseekable_open(inode, file);
 122}
 123
 124static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
 125{
 126        if (expect_close == 42)
 127                bcm63xx_wdt_pause();
 128        else {
 129                printk(KERN_CRIT PFX
 130                        ": Unexpected close, not stopping watchdog!\n");
 131                bcm63xx_wdt_start();
 132        }
 133        clear_bit(0, &bcm63xx_wdt_device.inuse);
 134        expect_close = 0;
 135        return 0;
 136}
 137
 138static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
 139                                size_t len, loff_t *ppos)
 140{
 141        if (len) {
 142                if (!nowayout) {
 143                        size_t i;
 144
 145                        /* In case it was set long ago */
 146                        expect_close = 0;
 147
 148                        for (i = 0; i != len; i++) {
 149                                char c;
 150                                if (get_user(c, data + i))
 151                                        return -EFAULT;
 152                                if (c == 'V')
 153                                        expect_close = 42;
 154                        }
 155                }
 156                bcm63xx_wdt_pet();
 157        }
 158        return len;
 159}
 160
 161static struct watchdog_info bcm63xx_wdt_info = {
 162        .identity       = PFX,
 163        .options        = WDIOF_SETTIMEOUT |
 164                                WDIOF_KEEPALIVEPING |
 165                                WDIOF_MAGICCLOSE,
 166};
 167
 168
 169static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
 170                                unsigned long arg)
 171{
 172        void __user *argp = (void __user *)arg;
 173        int __user *p = argp;
 174        int new_value, retval = -EINVAL;
 175
 176        switch (cmd) {
 177        case WDIOC_GETSUPPORT:
 178                return copy_to_user(argp, &bcm63xx_wdt_info,
 179                        sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
 180
 181        case WDIOC_GETSTATUS:
 182        case WDIOC_GETBOOTSTATUS:
 183                return put_user(0, p);
 184
 185        case WDIOC_SETOPTIONS:
 186                if (get_user(new_value, p))
 187                        return -EFAULT;
 188
 189                if (new_value & WDIOS_DISABLECARD) {
 190                        bcm63xx_wdt_pause();
 191                        retval = 0;
 192                }
 193                if (new_value & WDIOS_ENABLECARD) {
 194                        bcm63xx_wdt_start();
 195                        retval = 0;
 196                }
 197
 198                return retval;
 199
 200        case WDIOC_KEEPALIVE:
 201                bcm63xx_wdt_pet();
 202                return 0;
 203
 204        case WDIOC_SETTIMEOUT:
 205                if (get_user(new_value, p))
 206                        return -EFAULT;
 207
 208                if (bcm63xx_wdt_settimeout(new_value))
 209                        return -EINVAL;
 210
 211                bcm63xx_wdt_pet();
 212
 213        case WDIOC_GETTIMEOUT:
 214                return put_user(wdt_time, p);
 215
 216        default:
 217                return -ENOTTY;
 218
 219        }
 220}
 221
 222static const struct file_operations bcm63xx_wdt_fops = {
 223        .owner          = THIS_MODULE,
 224        .llseek         = no_llseek,
 225        .write          = bcm63xx_wdt_write,
 226        .unlocked_ioctl = bcm63xx_wdt_ioctl,
 227        .open           = bcm63xx_wdt_open,
 228        .release        = bcm63xx_wdt_release,
 229};
 230
 231static struct miscdevice bcm63xx_wdt_miscdev = {
 232        .minor  = WATCHDOG_MINOR,
 233        .name   = "watchdog",
 234        .fops   = &bcm63xx_wdt_fops,
 235};
 236
 237
 238static int __devinit bcm63xx_wdt_probe(struct platform_device *pdev)
 239{
 240        int ret;
 241        struct resource *r;
 242
 243        setup_timer(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0L);
 244
 245        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 246        if (!r) {
 247                dev_err(&pdev->dev, "failed to get resources\n");
 248                return -ENODEV;
 249        }
 250
 251        bcm63xx_wdt_device.regs = ioremap_nocache(r->start, r->end - r->start);
 252        if (!bcm63xx_wdt_device.regs) {
 253                dev_err(&pdev->dev, "failed to remap I/O resources\n");
 254                return -ENXIO;
 255        }
 256
 257        ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL);
 258        if (ret < 0) {
 259                dev_err(&pdev->dev, "failed to register wdt timer isr\n");
 260                goto unmap;
 261        }
 262
 263        if (bcm63xx_wdt_settimeout(wdt_time)) {
 264                bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
 265                dev_info(&pdev->dev,
 266                        ": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
 267                        wdt_time);
 268        }
 269
 270        ret = misc_register(&bcm63xx_wdt_miscdev);
 271        if (ret < 0) {
 272                dev_err(&pdev->dev, "failed to register watchdog device\n");
 273                goto unregister_timer;
 274        }
 275
 276        dev_info(&pdev->dev, " started, timer margin: %d sec\n",
 277                                                WDT_DEFAULT_TIME);
 278
 279        return 0;
 280
 281unregister_timer:
 282        bcm63xx_timer_unregister(TIMER_WDT_ID);
 283unmap:
 284        iounmap(bcm63xx_wdt_device.regs);
 285        return ret;
 286}
 287
 288static int __devexit bcm63xx_wdt_remove(struct platform_device *pdev)
 289{
 290        if (!nowayout)
 291                bcm63xx_wdt_pause();
 292
 293        misc_deregister(&bcm63xx_wdt_miscdev);
 294        bcm63xx_timer_unregister(TIMER_WDT_ID);
 295        iounmap(bcm63xx_wdt_device.regs);
 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 = {
 305        .probe  = bcm63xx_wdt_probe,
 306        .remove = __devexit_p(bcm63xx_wdt_remove),
 307        .shutdown = bcm63xx_wdt_shutdown,
 308        .driver = {
 309                .owner = THIS_MODULE,
 310                .name = "bcm63xx-wdt",
 311        }
 312};
 313
 314static int __init bcm63xx_wdt_init(void)
 315{
 316        return platform_driver_register(&bcm63xx_wdt);
 317}
 318
 319static void __exit bcm63xx_wdt_exit(void)
 320{
 321        platform_driver_unregister(&bcm63xx_wdt);
 322}
 323
 324module_init(bcm63xx_wdt_init);
 325module_exit(bcm63xx_wdt_exit);
 326
 327MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
 328MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 329MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
 330MODULE_LICENSE("GPL");
 331MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 332MODULE_ALIAS("platform:bcm63xx-wdt");
 333