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 #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
  42 static 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
  50 static int expect_close;
  51
  52 static int wdt_time = WDT_DEFAULT_TIME;
  53 static int nowayout = WATCHDOG_NOWAYOUT;
  54 module_param(nowayout, int, 0);
  55 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  56         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  57
  58 /* HW functions */
  59 static 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
  66 static 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
  72 static void bcm63xx_wdt_isr(void *data)
  73 {
  74         struct pt_regs *regs = get_irq_regs();
  75
  76         die(PFX " fire", regs);
  77 }
  78
  79 static 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
  88 static void bcm63xx_wdt_pet(void)
  89 {
  90         atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
  91 }
  92
  93 static void bcm63xx_wdt_start(void)
  94 {
  95         bcm63xx_wdt_pet();
  96         bcm63xx_timer_tick(0);
  97 }
  98
  99 static void bcm63xx_wdt_pause(void)
 100 {
 101         del_timer_sync(&bcm63xx_wdt_device.timer);
 102         bcm63xx_wdt_hw_stop();
 103 }
 104
 105 static 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
 115 static 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
 124 static 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
 138 static 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
 161 static struct watchdog_info bcm63xx_wdt_info = {
 162         .identity       = PFX,
 163         .options        = WDIOF_SETTIMEOUT |
 164                                 WDIOF_KEEPALIVEPING |
 165                                 WDIOF_MAGICCLOSE,
 166 };
 167
 168
 169 static 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
 222 static 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
 231 static struct miscdevice bcm63xx_wdt_miscdev = {
 232         .minor  = WATCHDOG_MINOR,
 233         .name   = "watchdog",
 234         .fops   = &bcm63xx_wdt_fops,
 235 };
 236
 237
 238 static 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, resource_size(r));
 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
 281 unregister_timer:
 282         bcm63xx_timer_unregister(TIMER_WDT_ID);
 283 unmap:
 284         iounmap(bcm63xx_wdt_device.regs);
 285         return ret;
 286 }
 287
 288 static 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
 299 static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
 300 {
 301         bcm63xx_wdt_pause();
 302 }
 303
 304 static 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
 314 module_platform_driver(bcm63xx_wdt);
 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");