drivers/watchdog/bcm63xx_wdt.c

   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
  45 static 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
  53 static int expect_close;
  54
  55 static int wdt_time = WDT_DEFAULT_TIME;
  56 static bool nowayout = WATCHDOG_NOWAYOUT;
  57 module_param(nowayout, bool, 0);
  58 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  59         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  60
  61 /* HW functions */
  62 static 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
  69 static 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
  75 static void bcm63xx_wdt_isr(void *data)
  76 {
  77         struct pt_regs *regs = get_irq_regs();
  78
  79         die(PFX " fire", regs);
  80 }
  81
  82 static 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
  91 static void bcm63xx_wdt_pet(void)
  92 {
  93         atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
  94 }
  95
  96 static void bcm63xx_wdt_start(void)
  97 {
  98         bcm63xx_wdt_pet();
  99         bcm63xx_timer_tick(0);
 100 }
 101
 102 static void bcm63xx_wdt_pause(void)
 103 {
 104         del_timer_sync(&bcm63xx_wdt_device.timer);
 105         bcm63xx_wdt_hw_stop();
 106 }
 107
 108 static 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
 118 static 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
 127 static 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
 140 static 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
 163 static struct watchdog_info bcm63xx_wdt_info = {
 164         .identity       = PFX,
 165         .options        = WDIOF_SETTIMEOUT |
 166                                 WDIOF_KEEPALIVEPING |
 167                                 WDIOF_MAGICCLOSE,
 168 };
 169
 170
 171 static 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
 224 static 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
 233 static struct miscdevice bcm63xx_wdt_miscdev = {
 234         .minor  = WATCHDOG_MINOR,
 235         .name   = "watchdog",
 236         .fops   = &bcm63xx_wdt_fops,
 237 };
 238
 239
 240 static 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
 284 unregister_timer:
 285         bcm63xx_timer_unregister(TIMER_WDT_ID);
 286         return ret;
 287 }
 288
 289 static 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
 299 static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
 300 {
 301         bcm63xx_wdt_pause();
 302 }
 303
 304 static 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
 314 module_platform_driver(bcm63xx_wdt_driver);
 315
 316 MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
 317 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 318 MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
 319 MODULE_LICENSE("GPL");
 320 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 321 MODULE_ALIAS("platform:bcm63xx-wdt");