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/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
  44 static 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
  52 static int expect_close;
  53
  54 static int wdt_time = WDT_DEFAULT_TIME;
  55 static bool nowayout = WATCHDOG_NOWAYOUT;
  56 module_param(nowayout, bool, 0);
  57 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  58         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  59
  60 /* HW functions */
  61 static 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
  68 static 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
  74 static void bcm63xx_wdt_isr(void *data)
  75 {
  76         struct pt_regs *regs = get_irq_regs();
  77
  78         die(PFX " fire", regs);
  79 }
  80
  81 static 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
  90 static void bcm63xx_wdt_pet(void)
  91 {
  92         atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
  93 }
  94
  95 static void bcm63xx_wdt_start(void)
  96 {
  97         bcm63xx_wdt_pet();
  98         bcm63xx_timer_tick(0);
  99 }
 100
 101 static void bcm63xx_wdt_pause(void)
 102 {
 103         del_timer_sync(&bcm63xx_wdt_device.timer);
 104         bcm63xx_wdt_hw_stop();
 105 }
 106
 107 static 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
 117 static 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
 126 static 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
 139 static 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
 162 static struct watchdog_info bcm63xx_wdt_info = {
 163         .identity       = PFX,
 164         .options        = WDIOF_SETTIMEOUT |
 165                                 WDIOF_KEEPALIVEPING |
 166                                 WDIOF_MAGICCLOSE,
 167 };
 168
 169
 170 static 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
 223 static 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
 232 static struct miscdevice bcm63xx_wdt_miscdev = {
 233         .minor  = WATCHDOG_MINOR,
 234         .name   = "watchdog",
 235         .fops   = &bcm63xx_wdt_fops,
 236 };
 237
 238
 239 static int 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
 282 unregister_timer:
 283         bcm63xx_timer_unregister(TIMER_WDT_ID);
 284 unmap:
 285         iounmap(bcm63xx_wdt_device.regs);
 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         iounmap(bcm63xx_wdt_device.regs);
 297         return 0;
 298 }
 299
 300 static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
 301 {
 302         bcm63xx_wdt_pause();
 303 }
 304
 305 static struct platform_driver bcm63xx_wdt_driver = {
 306         .probe  = bcm63xx_wdt_probe,
 307         .remove = bcm63xx_wdt_remove,
 308         .shutdown = bcm63xx_wdt_shutdown,
 309         .driver = {
 310                 .owner = THIS_MODULE,
 311                 .name = "bcm63xx-wdt",
 312         }
 313 };
 314
 315 module_platform_driver(bcm63xx_wdt_driver);
 316
 317 MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
 318 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 319 MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
 320 MODULE_LICENSE("GPL");
 321 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 322 MODULE_ALIAS("platform:bcm63xx-wdt");